/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

Bug Summary

File:	lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
Warning:	line 1003, column 9 Called C++ object pointer is null

Annotated Source Code

1	//===- RewriteStatepointsForGC.cpp - Make GC relocations explicit ---------===//
2	//
3	// The LLVM Compiler Infrastructure
4	//
5	// This file is distributed under the University of Illinois Open Source
6	// License. See LICENSE.TXT for details.
7	//
8	//===----------------------------------------------------------------------===//
9	//
10	// Rewrite call/invoke instructions so as to make potential relocations
11	// performed by the garbage collector explicit in the IR.
12	//
13	//===----------------------------------------------------------------------===//
14
15	#include "llvm/ADT/DenseSet.h"
16	#include "llvm/ADT/MapVector.h"
17	#include "llvm/ADT/SetOperations.h"
18	#include "llvm/ADT/SetVector.h"
19	#include "llvm/ADT/Statistic.h"
20	#include "llvm/ADT/StringRef.h"
21	#include "llvm/Analysis/CFG.h"
22	#include "llvm/Analysis/TargetTransformInfo.h"
23	#include "llvm/IR/BasicBlock.h"
24	#include "llvm/IR/CallSite.h"
25	#include "llvm/IR/Dominators.h"
26	#include "llvm/IR/Function.h"
27	#include "llvm/IR/IRBuilder.h"
28	#include "llvm/IR/InstIterator.h"
29	#include "llvm/IR/Instructions.h"
30	#include "llvm/IR/IntrinsicInst.h"
31	#include "llvm/IR/Intrinsics.h"
32	#include "llvm/IR/MDBuilder.h"
33	#include "llvm/IR/Module.h"
34	#include "llvm/IR/Statepoint.h"
35	#include "llvm/IR/Value.h"
36	#include "llvm/IR/Verifier.h"
37	#include "llvm/Pass.h"
38	#include "llvm/Support/CommandLine.h"
39	#include "llvm/Support/Debug.h"
40	#include "llvm/Transforms/Scalar.h"
41	#include "llvm/Transforms/Utils/BasicBlockUtils.h"
42	#include "llvm/Transforms/Utils/Cloning.h"
43	#include "llvm/Transforms/Utils/Local.h"
44	#include "llvm/Transforms/Utils/PromoteMemToReg.h"
45
46	#define DEBUG_TYPE"rewrite-statepoints-for-gc" "rewrite-statepoints-for-gc"
47
48	using namespace llvm;
49
50	// Print the liveset found at the insert location
51	static cl::opt<bool> PrintLiveSet("spp-print-liveset", cl::Hidden,
52	cl::init(false));
53	static cl::opt<bool> PrintLiveSetSize("spp-print-liveset-size", cl::Hidden,
54	cl::init(false));
55	// Print out the base pointers for debugging
56	static cl::opt<bool> PrintBasePointers("spp-print-base-pointers", cl::Hidden,
57	cl::init(false));
58
59	// Cost threshold measuring when it is profitable to rematerialize value instead
60	// of relocating it
61	static cl::opt<unsigned>
62	RematerializationThreshold("spp-rematerialization-threshold", cl::Hidden,
63	cl::init(6));
64
65	#ifdef EXPENSIVE_CHECKS
66	static bool ClobberNonLive = true;
67	#else
68	static bool ClobberNonLive = false;
69	#endif
70	static cl::opt<bool, true> ClobberNonLiveOverride("rs4gc-clobber-non-live",
71	cl::location(ClobberNonLive),
72	cl::Hidden);
73
74	static cl::opt<bool>
75	AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info",
76	cl::Hidden, cl::init(true));
77
78	namespace {
79	struct RewriteStatepointsForGC : public ModulePass {
80	static char ID; // Pass identification, replacement for typeid
81
82	RewriteStatepointsForGC() : ModulePass(ID) {
83	initializeRewriteStatepointsForGCPass(*PassRegistry::getPassRegistry());
84	}
85	bool runOnFunction(Function &F);
86	bool runOnModule(Module &M) override {
87	bool Changed = false;
88	for (Function &F : M)
89	Changed \|= runOnFunction(F);
90
91	if (Changed) {
92	// stripNonValidAttributesAndMetadata asserts that shouldRewriteStatepointsIn
93	// returns true for at least one function in the module. Since at least
94	// one function changed, we know that the precondition is satisfied.
95	stripNonValidAttributesAndMetadata(M);
96	}
97
98	return Changed;
99	}
100
101	void getAnalysisUsage(AnalysisUsage &AU) const override {
102	// We add and rewrite a bunch of instructions, but don't really do much
103	// else. We could in theory preserve a lot more analyses here.
104	AU.addRequired<DominatorTreeWrapperPass>();
105	AU.addRequired<TargetTransformInfoWrapperPass>();
106	}
107
108	/// The IR fed into RewriteStatepointsForGC may have had attributes and
109	/// metadata implying dereferenceability that are no longer valid/correct after
110	/// RewriteStatepointsForGC has run. This is because semantically, after
111	/// RewriteStatepointsForGC runs, all calls to gc.statepoint "free" the entire
112	/// heap. stripNonValidAttributesAndMetadata (conservatively) restores
113	/// correctness by erasing all attributes in the module that externally imply
114	/// dereferenceability. Similar reasoning also applies to the noalias
115	/// attributes and metadata. gc.statepoint can touch the entire heap including
116	/// noalias objects.
117	void stripNonValidAttributesAndMetadata(Module &M);
118
119	// Helpers for stripNonValidAttributesAndMetadata
120	void stripNonValidAttributesAndMetadataFromBody(Function &F);
121	void stripNonValidAttributesFromPrototype(Function &F);
122	// Certain metadata on instructions are invalid after running RS4GC.
123	// Optimizations that run after RS4GC can incorrectly use this metadata to
124	// optimize functions. We drop such metadata on the instruction.
125	void stripInvalidMetadataFromInstruction(Instruction &I);
126	};
127	} // namespace
128
129	char RewriteStatepointsForGC::ID = 0;
130
131	ModulePass *llvm::createRewriteStatepointsForGCPass() {
132	return new RewriteStatepointsForGC();
133	}
134
135	INITIALIZE_PASS_BEGIN(RewriteStatepointsForGC, "rewrite-statepoints-for-gc",static void *initializeRewriteStatepointsForGCPassOnce(PassRegistry &Registry) {
136	"Make relocations explicit at statepoints", false, false)static void *initializeRewriteStatepointsForGCPassOnce(PassRegistry &Registry) {
137	INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
138	INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
139	INITIALIZE_PASS_END(RewriteStatepointsForGC, "rewrite-statepoints-for-gc",PassInfo PI = new PassInfo( "Make relocations explicit at statepoints" , "rewrite-statepoints-for-gc", &RewriteStatepointsForGC:: ID, PassInfo::NormalCtor_t(callDefaultCtor<RewriteStatepointsForGC >), false, false); Registry.registerPass(PI, true); return PI; } static llvm::once_flag InitializeRewriteStatepointsForGCPassFlag ; void llvm::initializeRewriteStatepointsForGCPass(PassRegistry &Registry) { llvm::call_once(InitializeRewriteStatepointsForGCPassFlag , initializeRewriteStatepointsForGCPassOnce, std::ref(Registry )); }
140	"Make relocations explicit at statepoints", false, false)PassInfo PI = new PassInfo( "Make relocations explicit at statepoints" , "rewrite-statepoints-for-gc", &RewriteStatepointsForGC:: ID, PassInfo::NormalCtor_t(callDefaultCtor<RewriteStatepointsForGC >), false, false); Registry.registerPass(PI, true); return PI; } static llvm::once_flag InitializeRewriteStatepointsForGCPassFlag ; void llvm::initializeRewriteStatepointsForGCPass(PassRegistry &Registry) { llvm::call_once(InitializeRewriteStatepointsForGCPassFlag , initializeRewriteStatepointsForGCPassOnce, std::ref(Registry )); }
141
142	namespace {
143	struct GCPtrLivenessData {
144	/// Values defined in this block.
145	MapVector<BasicBlock , SetVector<Value >> KillSet;
146	/// Values used in this block (and thus live); does not included values
147	/// killed within this block.
148	MapVector<BasicBlock , SetVector<Value >> LiveSet;
149
150	/// Values live into this basic block (i.e. used by any
151	/// instruction in this basic block or ones reachable from here)
152	MapVector<BasicBlock , SetVector<Value >> LiveIn;
153
154	/// Values live out of this basic block (i.e. live into
155	/// any successor block)
156	MapVector<BasicBlock , SetVector<Value >> LiveOut;
157	};
158
159	// The type of the internal cache used inside the findBasePointers family
160	// of functions. From the callers perspective, this is an opaque type and
161	// should not be inspected.
162	//
163	// In the actual implementation this caches two relations:
164	// - The base relation itself (i.e. this pointer is based on that one)
165	// - The base defining value relation (i.e. before base_phi insertion)
166	// Generally, after the execution of a full findBasePointer call, only the
167	// base relation will remain. Internally, we add a mixture of the two
168	// types, then update all the second type to the first type
169	typedef MapVector<Value , Value > DefiningValueMapTy;
170	typedef SetVector<Value *> StatepointLiveSetTy;
171	typedef MapVector<AssertingVH<Instruction>, AssertingVH<Value>>
172	RematerializedValueMapTy;
173
174	struct PartiallyConstructedSafepointRecord {
175	/// The set of values known to be live across this safepoint
176	StatepointLiveSetTy LiveSet;
177
178	/// Mapping from live pointers to a base-defining-value
179	MapVector<Value , Value > PointerToBase;
180
181	/// The new gc.statepoint instruction itself. This produces the token
182	/// that normal path gc.relocates and the gc.result are tied to.
183	Instruction *StatepointToken;
184
185	/// Instruction to which exceptional gc relocates are attached
186	/// Makes it easier to iterate through them during relocationViaAlloca.
187	Instruction *UnwindToken;
188
189	/// Record live values we are rematerialized instead of relocating.
190	/// They are not included into 'LiveSet' field.
191	/// Maps rematerialized copy to it's original value.
192	RematerializedValueMapTy RematerializedValues;
193	};
194	}
195
196	static ArrayRef<Use> GetDeoptBundleOperands(ImmutableCallSite CS) {
197	Optional<OperandBundleUse> DeoptBundle =
198	CS.getOperandBundle(LLVMContext::OB_deopt);
199
200	if (!DeoptBundle.hasValue()) {
201	assert(AllowStatepointWithNoDeoptInfo &&((AllowStatepointWithNoDeoptInfo && "Found non-leaf call without deopt info!" ) ? static_cast<void> (0) : __assert_fail ("AllowStatepointWithNoDeoptInfo && \"Found non-leaf call without deopt info!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 202, __PRETTY_FUNCTION__))
202	"Found non-leaf call without deopt info!")((AllowStatepointWithNoDeoptInfo && "Found non-leaf call without deopt info!" ) ? static_cast<void> (0) : __assert_fail ("AllowStatepointWithNoDeoptInfo && \"Found non-leaf call without deopt info!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 202, __PRETTY_FUNCTION__));
203	return None;
204	}
205
206	return DeoptBundle.getValue().Inputs;
207	}
208
209	/// Compute the live-in set for every basic block in the function
210	static void computeLiveInValues(DominatorTree &DT, Function &F,
211	GCPtrLivenessData &Data);
212
213	/// Given results from the dataflow liveness computation, find the set of live
214	/// Values at a particular instruction.
215	static void findLiveSetAtInst(Instruction *inst, GCPtrLivenessData &Data,
216	StatepointLiveSetTy &out);
217
218	// TODO: Once we can get to the GCStrategy, this becomes
219	// Optional<bool> isGCManagedPointer(const Type *Ty) const override {
220
221	static bool isGCPointerType(Type *T) {
222	if (auto *PT = dyn_cast<PointerType>(T))
223	// For the sake of this example GC, we arbitrarily pick addrspace(1) as our
224	// GC managed heap. We know that a pointer into this heap needs to be
225	// updated and that no other pointer does.
226	return PT->getAddressSpace() == 1;
227	return false;
228	}
229
230	// Return true if this type is one which a) is a gc pointer or contains a GC
231	// pointer and b) is of a type this code expects to encounter as a live value.
232	// (The insertion code will assert that a type which matches (a) and not (b)
233	// is not encountered.)
234	static bool isHandledGCPointerType(Type *T) {
235	// We fully support gc pointers
236	if (isGCPointerType(T))
237	return true;
238	// We partially support vectors of gc pointers. The code will assert if it
239	// can't handle something.
240	if (auto VT = dyn_cast<VectorType>(T))
241	if (isGCPointerType(VT->getElementType()))
242	return true;
243	return false;
244	}
245
246	#ifndef NDEBUG
247	/// Returns true if this type contains a gc pointer whether we know how to
248	/// handle that type or not.
249	static bool containsGCPtrType(Type *Ty) {
250	if (isGCPointerType(Ty))
251	return true;
252	if (VectorType *VT = dyn_cast<VectorType>(Ty))
253	return isGCPointerType(VT->getScalarType());
254	if (ArrayType *AT = dyn_cast<ArrayType>(Ty))
255	return containsGCPtrType(AT->getElementType());
256	if (StructType *ST = dyn_cast<StructType>(Ty))
257	return any_of(ST->subtypes(), containsGCPtrType);
258	return false;
259	}
260
261	// Returns true if this is a type which a) is a gc pointer or contains a GC
262	// pointer and b) is of a type which the code doesn't expect (i.e. first class
263	// aggregates). Used to trip assertions.
264	static bool isUnhandledGCPointerType(Type *Ty) {
265	return containsGCPtrType(Ty) && !isHandledGCPointerType(Ty);
266	}
267	#endif
268
269	// Return the name of the value suffixed with the provided value, or if the
270	// value didn't have a name, the default value specified.
271	static std::string suffixed_name_or(Value *V, StringRef Suffix,
272	StringRef DefaultName) {
273	return V->hasName() ? (V->getName() + Suffix).str() : DefaultName.str();
274	}
275
276	// Conservatively identifies any definitions which might be live at the
277	// given instruction. The analysis is performed immediately before the
278	// given instruction. Values defined by that instruction are not considered
279	// live. Values used by that instruction are considered live.
280	static void
281	analyzeParsePointLiveness(DominatorTree &DT,
282	GCPtrLivenessData &OriginalLivenessData, CallSite CS,
283	PartiallyConstructedSafepointRecord &Result) {
284	Instruction *Inst = CS.getInstruction();
285
286	StatepointLiveSetTy LiveSet;
287	findLiveSetAtInst(Inst, OriginalLivenessData, LiveSet);
288
289	if (PrintLiveSet) {
290	dbgs() << "Live Variables:\n";
291	for (Value *V : LiveSet)
292	dbgs() << " " << V->getName() << " " << *V << "\n";
293	}
294	if (PrintLiveSetSize) {
295	dbgs() << "Safepoint For: " << CS.getCalledValue()->getName() << "\n";
296	dbgs() << "Number live values: " << LiveSet.size() << "\n";
297	}
298	Result.LiveSet = LiveSet;
299	}
300
301	static bool isKnownBaseResult(Value *V);
302	namespace {
303	/// A single base defining value - An immediate base defining value for an
304	/// instruction 'Def' is an input to 'Def' whose base is also a base of 'Def'.
305	/// For instructions which have multiple pointer [vector] inputs or that
306	/// transition between vector and scalar types, there is no immediate base
307	/// defining value. The 'base defining value' for 'Def' is the transitive
308	/// closure of this relation stopping at the first instruction which has no
309	/// immediate base defining value. The b.d.v. might itself be a base pointer,
310	/// but it can also be an arbitrary derived pointer.
311	struct BaseDefiningValueResult {
312	/// Contains the value which is the base defining value.
313	Value * const BDV;
314	/// True if the base defining value is also known to be an actual base
315	/// pointer.
316	const bool IsKnownBase;
317	BaseDefiningValueResult(Value *BDV, bool IsKnownBase)
318	: BDV(BDV), IsKnownBase(IsKnownBase) {
319	#ifndef NDEBUG
320	// Check consistency between new and old means of checking whether a BDV is
321	// a base.
322	bool MustBeBase = isKnownBaseResult(BDV);
323	assert(!MustBeBase \|\| MustBeBase == IsKnownBase)((!MustBeBase \|\| MustBeBase == IsKnownBase) ? static_cast< void> (0) : __assert_fail ("!MustBeBase \|\| MustBeBase == IsKnownBase" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 323, __PRETTY_FUNCTION__));
324	#endif
325	}
326	};
327	}
328
329	static BaseDefiningValueResult findBaseDefiningValue(Value *I);
330
331	/// Return a base defining value for the 'Index' element of the given vector
332	/// instruction 'I'. If Index is null, returns a BDV for the entire vector
333	/// 'I'. As an optimization, this method will try to determine when the
334	/// element is known to already be a base pointer. If this can be established,
335	/// the second value in the returned pair will be true. Note that either a
336	/// vector or a pointer typed value can be returned. For the former, the
337	/// vector returned is a BDV (and possibly a base) of the entire vector 'I'.
338	/// If the later, the return pointer is a BDV (or possibly a base) for the
339	/// particular element in 'I'.
340	static BaseDefiningValueResult
341	findBaseDefiningValueOfVector(Value *I) {
342	// Each case parallels findBaseDefiningValue below, see that code for
343	// detailed motivation.
344
345	if (isa<Argument>(I))
346	// An incoming argument to the function is a base pointer
347	return BaseDefiningValueResult(I, true);
348
349	if (isa<Constant>(I))
350	// Base of constant vector consists only of constant null pointers.
351	// For reasoning see similar case inside 'findBaseDefiningValue' function.
352	return BaseDefiningValueResult(ConstantAggregateZero::get(I->getType()),
353	true);
354
355	if (isa<LoadInst>(I))
356	return BaseDefiningValueResult(I, true);
357
358	if (isa<InsertElementInst>(I))
359	// We don't know whether this vector contains entirely base pointers or
360	// not. To be conservatively correct, we treat it as a BDV and will
361	// duplicate code as needed to construct a parallel vector of bases.
362	return BaseDefiningValueResult(I, false);
363
364	if (isa<ShuffleVectorInst>(I))
365	// We don't know whether this vector contains entirely base pointers or
366	// not. To be conservatively correct, we treat it as a BDV and will
367	// duplicate code as needed to construct a parallel vector of bases.
368	// TODO: There a number of local optimizations which could be applied here
369	// for particular sufflevector patterns.
370	return BaseDefiningValueResult(I, false);
371
372	// The behavior of getelementptr instructions is the same for vector and
373	// non-vector data types.
374	if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
375	return findBaseDefiningValue(GEP->getPointerOperand());
376
377	// A PHI or Select is a base defining value. The outer findBasePointer
378	// algorithm is responsible for constructing a base value for this BDV.
379	assert((isa<SelectInst>(I) \|\| isa<PHINode>(I)) &&(((isa<SelectInst>(I) \|\| isa<PHINode>(I)) && "unknown vector instruction - no base found for vector element" ) ? static_cast<void> (0) : __assert_fail ("(isa<SelectInst>(I) \|\| isa<PHINode>(I)) && \"unknown vector instruction - no base found for vector element\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 380, __PRETTY_FUNCTION__))
380	"unknown vector instruction - no base found for vector element")(((isa<SelectInst>(I) \|\| isa<PHINode>(I)) && "unknown vector instruction - no base found for vector element" ) ? static_cast<void> (0) : __assert_fail ("(isa<SelectInst>(I) \|\| isa<PHINode>(I)) && \"unknown vector instruction - no base found for vector element\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 380, __PRETTY_FUNCTION__));
381	return BaseDefiningValueResult(I, false);
382	}
383
384	/// Helper function for findBasePointer - Will return a value which either a)
385	/// defines the base pointer for the input, b) blocks the simple search
386	/// (i.e. a PHI or Select of two derived pointers), or c) involves a change
387	/// from pointer to vector type or back.
388	static BaseDefiningValueResult findBaseDefiningValue(Value *I) {
389	assert(I->getType()->isPtrOrPtrVectorTy() &&((I->getType()->isPtrOrPtrVectorTy() && "Illegal to ask for the base pointer of a non-pointer type" ) ? static_cast<void> (0) : __assert_fail ("I->getType()->isPtrOrPtrVectorTy() && \"Illegal to ask for the base pointer of a non-pointer type\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 390, __PRETTY_FUNCTION__))
390	"Illegal to ask for the base pointer of a non-pointer type")((I->getType()->isPtrOrPtrVectorTy() && "Illegal to ask for the base pointer of a non-pointer type" ) ? static_cast<void> (0) : __assert_fail ("I->getType()->isPtrOrPtrVectorTy() && \"Illegal to ask for the base pointer of a non-pointer type\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 390, __PRETTY_FUNCTION__));
391
392	if (I->getType()->isVectorTy())
393	return findBaseDefiningValueOfVector(I);
394
395	if (isa<Argument>(I))
396	// An incoming argument to the function is a base pointer
397	// We should have never reached here if this argument isn't an gc value
398	return BaseDefiningValueResult(I, true);
399
400	if (isa<Constant>(I)) {
401	// We assume that objects with a constant base (e.g. a global) can't move
402	// and don't need to be reported to the collector because they are always
403	// live. Besides global references, all kinds of constants (e.g. undef,
404	// constant expressions, null pointers) can be introduced by the inliner or
405	// the optimizer, especially on dynamically dead paths.
406	// Here we treat all of them as having single null base. By doing this we
407	// trying to avoid problems reporting various conflicts in a form of
408	// "phi (const1, const2)" or "phi (const, regular gc ptr)".
409	// See constant.ll file for relevant test cases.
410
411	return BaseDefiningValueResult(
412	ConstantPointerNull::get(cast<PointerType>(I->getType())), true);
413	}
414
415	if (CastInst *CI = dyn_cast<CastInst>(I)) {
416	Value *Def = CI->stripPointerCasts();
417	// If stripping pointer casts changes the address space there is an
418	// addrspacecast in between.
419	assert(cast<PointerType>(Def->getType())->getAddressSpace() ==((cast<PointerType>(Def->getType())->getAddressSpace () == cast<PointerType>(CI->getType())->getAddressSpace () && "unsupported addrspacecast") ? static_cast<void > (0) : __assert_fail ("cast<PointerType>(Def->getType())->getAddressSpace() == cast<PointerType>(CI->getType())->getAddressSpace() && \"unsupported addrspacecast\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 421, __PRETTY_FUNCTION__))
420	cast<PointerType>(CI->getType())->getAddressSpace() &&((cast<PointerType>(Def->getType())->getAddressSpace () == cast<PointerType>(CI->getType())->getAddressSpace () && "unsupported addrspacecast") ? static_cast<void > (0) : __assert_fail ("cast<PointerType>(Def->getType())->getAddressSpace() == cast<PointerType>(CI->getType())->getAddressSpace() && \"unsupported addrspacecast\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 421, __PRETTY_FUNCTION__))
421	"unsupported addrspacecast")((cast<PointerType>(Def->getType())->getAddressSpace () == cast<PointerType>(CI->getType())->getAddressSpace () && "unsupported addrspacecast") ? static_cast<void > (0) : __assert_fail ("cast<PointerType>(Def->getType())->getAddressSpace() == cast<PointerType>(CI->getType())->getAddressSpace() && \"unsupported addrspacecast\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 421, __PRETTY_FUNCTION__));
422	// If we find a cast instruction here, it means we've found a cast which is
423	// not simply a pointer cast (i.e. an inttoptr). We don't know how to
424	// handle int->ptr conversion.
425	assert(!isa<CastInst>(Def) && "shouldn't find another cast here")((!isa<CastInst>(Def) && "shouldn't find another cast here" ) ? static_cast<void> (0) : __assert_fail ("!isa<CastInst>(Def) && \"shouldn't find another cast here\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 425, __PRETTY_FUNCTION__));
426	return findBaseDefiningValue(Def);
427	}
428
429	if (isa<LoadInst>(I))
430	// The value loaded is an gc base itself
431	return BaseDefiningValueResult(I, true);
432
433
434	if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
435	// The base of this GEP is the base
436	return findBaseDefiningValue(GEP->getPointerOperand());
437
438	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
439	switch (II->getIntrinsicID()) {
440	default:
441	// fall through to general call handling
442	break;
443	case Intrinsic::experimental_gc_statepoint:
444	llvm_unreachable("statepoints don't produce pointers")::llvm::llvm_unreachable_internal("statepoints don't produce pointers" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 444);
445	case Intrinsic::experimental_gc_relocate: {
446	// Rerunning safepoint insertion after safepoints are already
447	// inserted is not supported. It could probably be made to work,
448	// but why are you doing this? There's no good reason.
449	llvm_unreachable("repeat safepoint insertion is not supported")::llvm::llvm_unreachable_internal("repeat safepoint insertion is not supported" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 449);
450	}
451	case Intrinsic::gcroot:
452	// Currently, this mechanism hasn't been extended to work with gcroot.
453	// There's no reason it couldn't be, but I haven't thought about the
454	// implications much.
455	llvm_unreachable(::llvm::llvm_unreachable_internal("interaction with the gcroot mechanism is not supported" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 456)
456	"interaction with the gcroot mechanism is not supported")::llvm::llvm_unreachable_internal("interaction with the gcroot mechanism is not supported" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 456);
457	}
458	}
459	// We assume that functions in the source language only return base
460	// pointers. This should probably be generalized via attributes to support
461	// both source language and internal functions.
462	if (isa<CallInst>(I) \|\| isa<InvokeInst>(I))
463	return BaseDefiningValueResult(I, true);
464
465	// TODO: I have absolutely no idea how to implement this part yet. It's not
466	// necessarily hard, I just haven't really looked at it yet.
467	assert(!isa<LandingPadInst>(I) && "Landing Pad is unimplemented")((!isa<LandingPadInst>(I) && "Landing Pad is unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isa<LandingPadInst>(I) && \"Landing Pad is unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 467, __PRETTY_FUNCTION__));
468
469	if (isa<AtomicCmpXchgInst>(I))
470	// A CAS is effectively a atomic store and load combined under a
471	// predicate. From the perspective of base pointers, we just treat it
472	// like a load.
473	return BaseDefiningValueResult(I, true);
474
475	assert(!isa<AtomicRMWInst>(I) && "Xchg handled above, all others are "((!isa<AtomicRMWInst>(I) && "Xchg handled above, all others are " "binary ops which don't apply to pointers") ? static_cast< void> (0) : __assert_fail ("!isa<AtomicRMWInst>(I) && \"Xchg handled above, all others are \" \"binary ops which don't apply to pointers\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 476, __PRETTY_FUNCTION__))
476	"binary ops which don't apply to pointers")((!isa<AtomicRMWInst>(I) && "Xchg handled above, all others are " "binary ops which don't apply to pointers") ? static_cast< void> (0) : __assert_fail ("!isa<AtomicRMWInst>(I) && \"Xchg handled above, all others are \" \"binary ops which don't apply to pointers\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 476, __PRETTY_FUNCTION__));
477
478	// The aggregate ops. Aggregates can either be in the heap or on the
479	// stack, but in either case, this is simply a field load. As a result,
480	// this is a defining definition of the base just like a load is.
481	if (isa<ExtractValueInst>(I))
482	return BaseDefiningValueResult(I, true);
483
484	// We should never see an insert vector since that would require we be
485	// tracing back a struct value not a pointer value.
486	assert(!isa<InsertValueInst>(I) &&((!isa<InsertValueInst>(I) && "Base pointer for a struct is meaningless" ) ? static_cast<void> (0) : __assert_fail ("!isa<InsertValueInst>(I) && \"Base pointer for a struct is meaningless\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 487, __PRETTY_FUNCTION__))
487	"Base pointer for a struct is meaningless")((!isa<InsertValueInst>(I) && "Base pointer for a struct is meaningless" ) ? static_cast<void> (0) : __assert_fail ("!isa<InsertValueInst>(I) && \"Base pointer for a struct is meaningless\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 487, __PRETTY_FUNCTION__));
488
489	// An extractelement produces a base result exactly when it's input does.
490	// We may need to insert a parallel instruction to extract the appropriate
491	// element out of the base vector corresponding to the input. Given this,
492	// it's analogous to the phi and select case even though it's not a merge.
493	if (isa<ExtractElementInst>(I))
494	// Note: There a lot of obvious peephole cases here. This are deliberately
495	// handled after the main base pointer inference algorithm to make writing
496	// test cases to exercise that code easier.
497	return BaseDefiningValueResult(I, false);
498
499	// The last two cases here don't return a base pointer. Instead, they
500	// return a value which dynamically selects from among several base
501	// derived pointers (each with it's own base potentially). It's the job of
502	// the caller to resolve these.
503	assert((isa<SelectInst>(I) \|\| isa<PHINode>(I)) &&(((isa<SelectInst>(I) \|\| isa<PHINode>(I)) && "missing instruction case in findBaseDefiningValing") ? static_cast <void> (0) : __assert_fail ("(isa<SelectInst>(I) \|\| isa<PHINode>(I)) && \"missing instruction case in findBaseDefiningValing\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 504, __PRETTY_FUNCTION__))
504	"missing instruction case in findBaseDefiningValing")(((isa<SelectInst>(I) \|\| isa<PHINode>(I)) && "missing instruction case in findBaseDefiningValing") ? static_cast <void> (0) : __assert_fail ("(isa<SelectInst>(I) \|\| isa<PHINode>(I)) && \"missing instruction case in findBaseDefiningValing\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 504, __PRETTY_FUNCTION__));
505	return BaseDefiningValueResult(I, false);
506	}
507
508	/// Returns the base defining value for this value.
509	static Value findBaseDefiningValueCached(Value I, DefiningValueMapTy &Cache) {
510	Value *&Cached = Cache[I];
511	if (!Cached) {
512	Cached = findBaseDefiningValue(I).BDV;
513	DEBUG(dbgs() << "fBDV-cached: " << I->getName() << " -> "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "fBDV-cached: " << I->getName() << " -> " << Cached-> getName() << "\n"; } } while (false)
514	<< Cached->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "fBDV-cached: " << I->getName() << " -> " << Cached-> getName() << "\n"; } } while (false);
515	}
516	assert(Cache[I] != nullptr)((Cache[I] != nullptr) ? static_cast<void> (0) : __assert_fail ("Cache[I] != nullptr", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 516, __PRETTY_FUNCTION__));
517	return Cached;
518	}
519
520	/// Return a base pointer for this value if known. Otherwise, return it's
521	/// base defining value.
522	static Value findBaseOrBDV(Value I, DefiningValueMapTy &Cache) {
523	Value *Def = findBaseDefiningValueCached(I, Cache);
524	auto Found = Cache.find(Def);
525	if (Found != Cache.end()) {
526	// Either a base-of relation, or a self reference. Caller must check.
527	return Found->second;
528	}
529	// Only a BDV available
530	return Def;
531	}
532
533	/// Given the result of a call to findBaseDefiningValue, or findBaseOrBDV,
534	/// is it known to be a base pointer? Or do we need to continue searching.
535	static bool isKnownBaseResult(Value *V) {
536	if (!isa<PHINode>(V) && !isa<SelectInst>(V) &&
537	!isa<ExtractElementInst>(V) && !isa<InsertElementInst>(V) &&
538	!isa<ShuffleVectorInst>(V)) {
539	// no recursion possible
540	return true;
541	}
542	if (isa<Instruction>(V) &&
543	cast<Instruction>(V)->getMetadata("is_base_value")) {
544	// This is a previously inserted base phi or select. We know
545	// that this is a base value.
546	return true;
547	}
548
549	// We need to keep searching
550	return false;
551	}
552
553	namespace {
554	/// Models the state of a single base defining value in the findBasePointer
555	/// algorithm for determining where a new instruction is needed to propagate
556	/// the base of this BDV.
557	class BDVState {
558	public:
559	enum Status { Unknown, Base, Conflict };
560
561	BDVState() : Status(Unknown), BaseValue(nullptr) {}
562
563	explicit BDVState(Status Status, Value *BaseValue = nullptr)
564	: Status(Status), BaseValue(BaseValue) {
565	assert(Status != Base \|\| BaseValue)((Status != Base \|\| BaseValue) ? static_cast<void> (0) : __assert_fail ("Status != Base \|\| BaseValue", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 565, __PRETTY_FUNCTION__));
566	}
567
568	explicit BDVState(Value *BaseValue) : Status(Base), BaseValue(BaseValue) {}
569
570	Status getStatus() const { return Status; }
571	Value *getBaseValue() const { return BaseValue; }
572
573	bool isBase() const { return getStatus() == Base; }
574	bool isUnknown() const { return getStatus() == Unknown; }
575	bool isConflict() const { return getStatus() == Conflict; }
576
577	bool operator==(const BDVState &Other) const {
578	return BaseValue == Other.BaseValue && Status == Other.Status;
579	}
580
581	bool operator!=(const BDVState &other) const { return !(*this == other); }
582
583	LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__))
584	void dump() const {
585	print(dbgs());
586	dbgs() << '\n';
587	}
588
589	void print(raw_ostream &OS) const {
590	switch (getStatus()) {
591	case Unknown:
592	OS << "U";
593	break;
594	case Base:
595	OS << "B";
596	break;
597	case Conflict:
598	OS << "C";
599	break;
600	};
601	OS << " (" << getBaseValue() << " - "
602	<< (getBaseValue() ? getBaseValue()->getName() : "nullptr") << "): ";
603	}
604
605	private:
606	Status Status;
607	AssertingVH<Value> BaseValue; // Non-null only if Status == Base.
608	};
609	}
610
611	#ifndef NDEBUG
612	static raw_ostream &operator<<(raw_ostream &OS, const BDVState &State) {
613	State.print(OS);
614	return OS;
615	}
616	#endif
617
618	static BDVState meetBDVStateImpl(const BDVState &LHS, const BDVState &RHS) {
619	switch (LHS.getStatus()) {
620	case BDVState::Unknown:
621	return RHS;
622
623	case BDVState::Base:
624	assert(LHS.getBaseValue() && "can't be null")((LHS.getBaseValue() && "can't be null") ? static_cast <void> (0) : __assert_fail ("LHS.getBaseValue() && \"can't be null\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 624, __PRETTY_FUNCTION__));
625	if (RHS.isUnknown())
626	return LHS;
627
628	if (RHS.isBase()) {
629	if (LHS.getBaseValue() == RHS.getBaseValue()) {
630	assert(LHS == RHS && "equality broken!")((LHS == RHS && "equality broken!") ? static_cast< void> (0) : __assert_fail ("LHS == RHS && \"equality broken!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 630, __PRETTY_FUNCTION__));
631	return LHS;
632	}
633	return BDVState(BDVState::Conflict);
634	}
635	assert(RHS.isConflict() && "only three states!")((RHS.isConflict() && "only three states!") ? static_cast <void> (0) : __assert_fail ("RHS.isConflict() && \"only three states!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 635, __PRETTY_FUNCTION__));
636	return BDVState(BDVState::Conflict);
637
638	case BDVState::Conflict:
639	return LHS;
640	}
641	llvm_unreachable("only three states!")::llvm::llvm_unreachable_internal("only three states!", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 641);
642	}
643
644	// Values of type BDVState form a lattice, and this function implements the meet
645	// operation.
646	static BDVState meetBDVState(const BDVState &LHS, const BDVState &RHS) {
647	BDVState Result = meetBDVStateImpl(LHS, RHS);
648	assert(Result == meetBDVStateImpl(RHS, LHS) &&((Result == meetBDVStateImpl(RHS, LHS) && "Math is wrong: meet does not commute!" ) ? static_cast<void> (0) : __assert_fail ("Result == meetBDVStateImpl(RHS, LHS) && \"Math is wrong: meet does not commute!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 649, __PRETTY_FUNCTION__))
649	"Math is wrong: meet does not commute!")((Result == meetBDVStateImpl(RHS, LHS) && "Math is wrong: meet does not commute!" ) ? static_cast<void> (0) : __assert_fail ("Result == meetBDVStateImpl(RHS, LHS) && \"Math is wrong: meet does not commute!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 649, __PRETTY_FUNCTION__));
650	return Result;
651	}
652
653	/// For a given value or instruction, figure out what base ptr its derived from.
654	/// For gc objects, this is simply itself. On success, returns a value which is
655	/// the base pointer. (This is reliable and can be used for relocation.) On
656	/// failure, returns nullptr.
657	static Value findBasePointer(Value I, DefiningValueMapTy &Cache) {
658	Value *Def = findBaseOrBDV(I, Cache);
659
660	if (isKnownBaseResult(Def))
661	return Def;
662
663	// Here's the rough algorithm:
664	// - For every SSA value, construct a mapping to either an actual base
665	// pointer or a PHI which obscures the base pointer.
666	// - Construct a mapping from PHI to unknown TOP state. Use an
667	// optimistic algorithm to propagate base pointer information. Lattice
668	// looks like:
669	// UNKNOWN
670	// b1 b2 b3 b4
671	// CONFLICT
672	// When algorithm terminates, all PHIs will either have a single concrete
673	// base or be in a conflict state.
674	// - For every conflict, insert a dummy PHI node without arguments. Add
675	// these to the base[Instruction] = BasePtr mapping. For every
676	// non-conflict, add the actual base.
677	// - For every conflict, add arguments for the base[a] of each input
678	// arguments.
679	//
680	// Note: A simpler form of this would be to add the conflict form of all
681	// PHIs without running the optimistic algorithm. This would be
682	// analogous to pessimistic data flow and would likely lead to an
683	// overall worse solution.
684
685	#ifndef NDEBUG
686	auto isExpectedBDVType = [](Value *BDV) {
687	return isa<PHINode>(BDV) \|\| isa<SelectInst>(BDV) \|\|
688	isa<ExtractElementInst>(BDV) \|\| isa<InsertElementInst>(BDV) \|\|
689	isa<ShuffleVectorInst>(BDV);
690	};
691	#endif
692
693	// Once populated, will contain a mapping from each potentially non-base BDV
694	// to a lattice value (described above) which corresponds to that BDV.
695	// We use the order of insertion (DFS over the def/use graph) to provide a
696	// stable deterministic ordering for visiting DenseMaps (which are unordered)
697	// below. This is important for deterministic compilation.
698	MapVector<Value *, BDVState> States;
699
700	// Recursively fill in all base defining values reachable from the initial
701	// one for which we don't already know a definite base value for
702	/* scope */ {
703	SmallVector<Value*, 16> Worklist;
704	Worklist.push_back(Def);
705	States.insert({Def, BDVState()});
706	while (!Worklist.empty()) {
707	Value *Current = Worklist.pop_back_val();
708	assert(!isKnownBaseResult(Current) && "why did it get added?")((!isKnownBaseResult(Current) && "why did it get added?" ) ? static_cast<void> (0) : __assert_fail ("!isKnownBaseResult(Current) && \"why did it get added?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 708, __PRETTY_FUNCTION__));
709
710	auto visitIncomingValue = [&](Value *InVal) {
711	Value *Base = findBaseOrBDV(InVal, Cache);
712	if (isKnownBaseResult(Base))
713	// Known bases won't need new instructions introduced and can be
714	// ignored safely
715	return;
716	assert(isExpectedBDVType(Base) && "the only non-base values "((isExpectedBDVType(Base) && "the only non-base values " "we see should be base defining values") ? static_cast<void > (0) : __assert_fail ("isExpectedBDVType(Base) && \"the only non-base values \" \"we see should be base defining values\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 717, __PRETTY_FUNCTION__))
717	"we see should be base defining values")((isExpectedBDVType(Base) && "the only non-base values " "we see should be base defining values") ? static_cast<void > (0) : __assert_fail ("isExpectedBDVType(Base) && \"the only non-base values \" \"we see should be base defining values\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 717, __PRETTY_FUNCTION__));
718	if (States.insert(std::make_pair(Base, BDVState())).second)
719	Worklist.push_back(Base);
720	};
721	if (PHINode *PN = dyn_cast<PHINode>(Current)) {
722	for (Value *InVal : PN->incoming_values())
723	visitIncomingValue(InVal);
724	} else if (SelectInst *SI = dyn_cast<SelectInst>(Current)) {
725	visitIncomingValue(SI->getTrueValue());
726	visitIncomingValue(SI->getFalseValue());
727	} else if (auto *EE = dyn_cast<ExtractElementInst>(Current)) {
728	visitIncomingValue(EE->getVectorOperand());
729	} else if (auto *IE = dyn_cast<InsertElementInst>(Current)) {
730	visitIncomingValue(IE->getOperand(0)); // vector operand
731	visitIncomingValue(IE->getOperand(1)); // scalar operand
732	} else if (auto *SV = dyn_cast<ShuffleVectorInst>(Current)) {
733	visitIncomingValue(SV->getOperand(0));
734	visitIncomingValue(SV->getOperand(1));
735	}
736	else {
737	llvm_unreachable("Unimplemented instruction case")::llvm::llvm_unreachable_internal("Unimplemented instruction case" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 737);
738	}
739	}
740	}
741
742	#ifndef NDEBUG
743	DEBUG(dbgs() << "States after initialization:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "States after initialization:\n" ; } } while (false);
744	for (auto Pair : States) {
745	DEBUG(dbgs() << " " << Pair.second << " for " << Pair.first << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << " " << Pair.second << " for " << Pair.first << "\n" ; } } while (false);
746	}
747	#endif
748
749	// Return a phi state for a base defining value. We'll generate a new
750	// base state for known bases and expect to find a cached state otherwise.
751	auto getStateForBDV = [&](Value *baseValue) {
752	if (isKnownBaseResult(baseValue))
753	return BDVState(baseValue);
754	auto I = States.find(baseValue);
755	assert(I != States.end() && "lookup failed!")((I != States.end() && "lookup failed!") ? static_cast <void> (0) : __assert_fail ("I != States.end() && \"lookup failed!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 755, __PRETTY_FUNCTION__));
756	return I->second;
757	};
758
759	bool Progress = true;
760	while (Progress) {
761	#ifndef NDEBUG
762	const size_t OldSize = States.size();
763	#endif
764	Progress = false;
765	// We're only changing values in this loop, thus safe to keep iterators.
766	// Since this is computing a fixed point, the order of visit does not
767	// effect the result. TODO: We could use a worklist here and make this run
768	// much faster.
769	for (auto Pair : States) {
770	Value *BDV = Pair.first;
771	assert(!isKnownBaseResult(BDV) && "why did it get added?")((!isKnownBaseResult(BDV) && "why did it get added?") ? static_cast<void> (0) : __assert_fail ("!isKnownBaseResult(BDV) && \"why did it get added?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 771, __PRETTY_FUNCTION__));
772
773	// Given an input value for the current instruction, return a BDVState
774	// instance which represents the BDV of that value.
775	auto getStateForInput = [&](Value *V) mutable {
776	Value *BDV = findBaseOrBDV(V, Cache);
777	return getStateForBDV(BDV);
778	};
779
780	BDVState NewState;
781	if (SelectInst *SI = dyn_cast<SelectInst>(BDV)) {
782	NewState = meetBDVState(NewState, getStateForInput(SI->getTrueValue()));
783	NewState =
784	meetBDVState(NewState, getStateForInput(SI->getFalseValue()));
785	} else if (PHINode *PN = dyn_cast<PHINode>(BDV)) {
786	for (Value *Val : PN->incoming_values())
787	NewState = meetBDVState(NewState, getStateForInput(Val));
788	} else if (auto *EE = dyn_cast<ExtractElementInst>(BDV)) {
789	// The 'meet' for an extractelement is slightly trivial, but it's still
790	// useful in that it drives us to conflict if our input is.
791	NewState =
792	meetBDVState(NewState, getStateForInput(EE->getVectorOperand()));
793	} else if (auto *IE = dyn_cast<InsertElementInst>(BDV)){
794	// Given there's a inherent type mismatch between the operands, will
795	// always produce Conflict.
796	NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(0)));
797	NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(1)));
798	} else {
799	// The only instance this does not return a Conflict is when both the
800	// vector operands are the same vector.
801	auto *SV = cast<ShuffleVectorInst>(BDV);
802	NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(0)));
803	NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(1)));
804	}
805
806	BDVState OldState = States[BDV];
807	if (OldState != NewState) {
808	Progress = true;
809	States[BDV] = NewState;
810	}
811	}
812
813	assert(OldSize == States.size() &&((OldSize == States.size() && "fixed point shouldn't be adding any new nodes to state" ) ? static_cast<void> (0) : __assert_fail ("OldSize == States.size() && \"fixed point shouldn't be adding any new nodes to state\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 814, __PRETTY_FUNCTION__))
814	"fixed point shouldn't be adding any new nodes to state")((OldSize == States.size() && "fixed point shouldn't be adding any new nodes to state" ) ? static_cast<void> (0) : __assert_fail ("OldSize == States.size() && \"fixed point shouldn't be adding any new nodes to state\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 814, __PRETTY_FUNCTION__));
815	}
816
817	#ifndef NDEBUG
818	DEBUG(dbgs() << "States after meet iteration:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "States after meet iteration:\n" ; } } while (false);
819	for (auto Pair : States) {
820	DEBUG(dbgs() << " " << Pair.second << " for " << Pair.first << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << " " << Pair.second << " for " << Pair.first << "\n" ; } } while (false);
821	}
822	#endif
823
824	// Insert Phis for all conflicts
825	// TODO: adjust naming patterns to avoid this order of iteration dependency
826	for (auto Pair : States) {
827	Instruction *I = cast<Instruction>(Pair.first);
828	BDVState State = Pair.second;
829	assert(!isKnownBaseResult(I) && "why did it get added?")((!isKnownBaseResult(I) && "why did it get added?") ? static_cast<void> (0) : __assert_fail ("!isKnownBaseResult(I) && \"why did it get added?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 829, __PRETTY_FUNCTION__));
830	assert(!State.isUnknown() && "Optimistic algorithm didn't complete!")((!State.isUnknown() && "Optimistic algorithm didn't complete!" ) ? static_cast<void> (0) : __assert_fail ("!State.isUnknown() && \"Optimistic algorithm didn't complete!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 830, __PRETTY_FUNCTION__));
831
832	// extractelement instructions are a bit special in that we may need to
833	// insert an extract even when we know an exact base for the instruction.
834	// The problem is that we need to convert from a vector base to a scalar
835	// base for the particular indice we're interested in.
836	if (State.isBase() && isa<ExtractElementInst>(I) &&
837	isa<VectorType>(State.getBaseValue()->getType())) {
838	auto *EE = cast<ExtractElementInst>(I);
839	// TODO: In many cases, the new instruction is just EE itself. We should
840	// exploit this, but can't do it here since it would break the invariant
841	// about the BDV not being known to be a base.
842	auto *BaseInst = ExtractElementInst::Create(
843	State.getBaseValue(), EE->getIndexOperand(), "base_ee", EE);
844	BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
845	States[I] = BDVState(BDVState::Base, BaseInst);
846	}
847
848	// Since we're joining a vector and scalar base, they can never be the
849	// same. As a result, we should always see insert element having reached
850	// the conflict state.
851	assert(!isa<InsertElementInst>(I) \|\| State.isConflict())((!isa<InsertElementInst>(I) \|\| State.isConflict()) ? static_cast <void> (0) : __assert_fail ("!isa<InsertElementInst>(I) \|\| State.isConflict()" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 851, __PRETTY_FUNCTION__));
852
853	if (!State.isConflict())
854	continue;
855
856	/// Create and insert a new instruction which will represent the base of
857	/// the given instruction 'I'.
858	auto MakeBaseInstPlaceholder = [](Instruction I) -> Instruction {
859	if (isa<PHINode>(I)) {
860	BasicBlock *BB = I->getParent();
861	int NumPreds = std::distance(pred_begin(BB), pred_end(BB));
862	assert(NumPreds > 0 && "how did we reach here")((NumPreds > 0 && "how did we reach here") ? static_cast <void> (0) : __assert_fail ("NumPreds > 0 && \"how did we reach here\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 862, __PRETTY_FUNCTION__));
863	std::string Name = suffixed_name_or(I, ".base", "base_phi");
864	return PHINode::Create(I->getType(), NumPreds, Name, I);
865	} else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
866	// The undef will be replaced later
867	UndefValue *Undef = UndefValue::get(SI->getType());
868	std::string Name = suffixed_name_or(I, ".base", "base_select");
869	return SelectInst::Create(SI->getCondition(), Undef, Undef, Name, SI);
870	} else if (auto *EE = dyn_cast<ExtractElementInst>(I)) {
871	UndefValue *Undef = UndefValue::get(EE->getVectorOperand()->getType());
872	std::string Name = suffixed_name_or(I, ".base", "base_ee");
873	return ExtractElementInst::Create(Undef, EE->getIndexOperand(), Name,
874	EE);
875	} else if (auto *IE = dyn_cast<InsertElementInst>(I)) {
876	UndefValue *VecUndef = UndefValue::get(IE->getOperand(0)->getType());
877	UndefValue *ScalarUndef = UndefValue::get(IE->getOperand(1)->getType());
878	std::string Name = suffixed_name_or(I, ".base", "base_ie");
879	return InsertElementInst::Create(VecUndef, ScalarUndef,
880	IE->getOperand(2), Name, IE);
881	} else {
882	auto *SV = cast<ShuffleVectorInst>(I);
883	UndefValue *VecUndef = UndefValue::get(SV->getOperand(0)->getType());
884	std::string Name = suffixed_name_or(I, ".base", "base_sv");
885	return new ShuffleVectorInst(VecUndef, VecUndef, SV->getOperand(2),
886	Name, SV);
887	}
888	};
889	Instruction *BaseInst = MakeBaseInstPlaceholder(I);
890	// Add metadata marking this as a base value
891	BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
892	States[I] = BDVState(BDVState::Conflict, BaseInst);
893	}
894
895	// Returns a instruction which produces the base pointer for a given
896	// instruction. The instruction is assumed to be an input to one of the BDVs
897	// seen in the inference algorithm above. As such, we must either already
898	// know it's base defining value is a base, or have inserted a new
899	// instruction to propagate the base of it's BDV and have entered that newly
900	// introduced instruction into the state table. In either case, we are
901	// assured to be able to determine an instruction which produces it's base
902	// pointer.
903	auto getBaseForInput = [&](Value Input, Instruction InsertPt) {
904	Value *BDV = findBaseOrBDV(Input, Cache);
905	Value *Base = nullptr;
906	if (isKnownBaseResult(BDV)) {
907	Base = BDV;
908	} else {
909	// Either conflict or base.
910	assert(States.count(BDV))((States.count(BDV)) ? static_cast<void> (0) : __assert_fail ("States.count(BDV)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 910, __PRETTY_FUNCTION__));
911	Base = States[BDV].getBaseValue();
912	}
913	assert(Base && "Can't be null")((Base && "Can't be null") ? static_cast<void> ( 0) : __assert_fail ("Base && \"Can't be null\"", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 913, __PRETTY_FUNCTION__));
914	// The cast is needed since base traversal may strip away bitcasts
915	if (Base->getType() != Input->getType() && InsertPt)
916	Base = new BitCastInst(Base, Input->getType(), "cast", InsertPt);
917	return Base;
918	};
919
920	// Fixup all the inputs of the new PHIs. Visit order needs to be
921	// deterministic and predictable because we're naming newly created
922	// instructions.
923	for (auto Pair : States) {
924	Instruction *BDV = cast<Instruction>(Pair.first);
925	BDVState State = Pair.second;
926
927	assert(!isKnownBaseResult(BDV) && "why did it get added?")((!isKnownBaseResult(BDV) && "why did it get added?") ? static_cast<void> (0) : __assert_fail ("!isKnownBaseResult(BDV) && \"why did it get added?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 927, __PRETTY_FUNCTION__));
928	assert(!State.isUnknown() && "Optimistic algorithm didn't complete!")((!State.isUnknown() && "Optimistic algorithm didn't complete!" ) ? static_cast<void> (0) : __assert_fail ("!State.isUnknown() && \"Optimistic algorithm didn't complete!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 928, __PRETTY_FUNCTION__));
929	if (!State.isConflict())
930	continue;
931
932	if (PHINode *BasePHI = dyn_cast<PHINode>(State.getBaseValue())) {
933	PHINode *PN = cast<PHINode>(BDV);
934	unsigned NumPHIValues = PN->getNumIncomingValues();
935	for (unsigned i = 0; i < NumPHIValues; i++) {
936	Value *InVal = PN->getIncomingValue(i);
937	BasicBlock *InBB = PN->getIncomingBlock(i);
938
939	// If we've already seen InBB, add the same incoming value
940	// we added for it earlier. The IR verifier requires phi
941	// nodes with multiple entries from the same basic block
942	// to have the same incoming value for each of those
943	// entries. If we don't do this check here and basephi
944	// has a different type than base, we'll end up adding two
945	// bitcasts (and hence two distinct values) as incoming
946	// values for the same basic block.
947
948	int BlockIndex = BasePHI->getBasicBlockIndex(InBB);
949	if (BlockIndex != -1) {
950	Value *OldBase = BasePHI->getIncomingValue(BlockIndex);
951	BasePHI->addIncoming(OldBase, InBB);
952
953	#ifndef NDEBUG
954	Value *Base = getBaseForInput(InVal, nullptr);
955	// In essence this assert states: the only way two values
956	// incoming from the same basic block may be different is by
957	// being different bitcasts of the same value. A cleanup
958	// that remains TODO is changing findBaseOrBDV to return an
959	// llvm::Value of the correct type (and still remain pure).
960	// This will remove the need to add bitcasts.
961	assert(Base->stripPointerCasts() == OldBase->stripPointerCasts() &&((Base->stripPointerCasts() == OldBase->stripPointerCasts () && "Sanity -- findBaseOrBDV should be pure!") ? static_cast <void> (0) : __assert_fail ("Base->stripPointerCasts() == OldBase->stripPointerCasts() && \"Sanity -- findBaseOrBDV should be pure!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 962, __PRETTY_FUNCTION__))
962	"Sanity -- findBaseOrBDV should be pure!")((Base->stripPointerCasts() == OldBase->stripPointerCasts () && "Sanity -- findBaseOrBDV should be pure!") ? static_cast <void> (0) : __assert_fail ("Base->stripPointerCasts() == OldBase->stripPointerCasts() && \"Sanity -- findBaseOrBDV should be pure!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 962, __PRETTY_FUNCTION__));
963	#endif
964	continue;
965	}
966
967	// Find the instruction which produces the base for each input. We may
968	// need to insert a bitcast in the incoming block.
969	// TODO: Need to split critical edges if insertion is needed
970	Value *Base = getBaseForInput(InVal, InBB->getTerminator());
971	BasePHI->addIncoming(Base, InBB);
972	}
973	assert(BasePHI->getNumIncomingValues() == NumPHIValues)((BasePHI->getNumIncomingValues() == NumPHIValues) ? static_cast <void> (0) : __assert_fail ("BasePHI->getNumIncomingValues() == NumPHIValues" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 973, __PRETTY_FUNCTION__));
974	} else if (SelectInst *BaseSI =
975	dyn_cast<SelectInst>(State.getBaseValue())) {
976	SelectInst *SI = cast<SelectInst>(BDV);
977
978	// Find the instruction which produces the base for each input.
979	// We may need to insert a bitcast.
980	BaseSI->setTrueValue(getBaseForInput(SI->getTrueValue(), BaseSI));
981	BaseSI->setFalseValue(getBaseForInput(SI->getFalseValue(), BaseSI));
982	} else if (auto *BaseEE =
983	dyn_cast<ExtractElementInst>(State.getBaseValue())) {
984	Value *InVal = cast<ExtractElementInst>(BDV)->getVectorOperand();
985	// Find the instruction which produces the base for each input. We may
986	// need to insert a bitcast.
987	BaseEE->setOperand(0, getBaseForInput(InVal, BaseEE));
988	} else if (auto *BaseIE = dyn_cast<InsertElementInst>(State.getBaseValue())){
989	auto *BdvIE = cast<InsertElementInst>(BDV);
990	auto UpdateOperand = [&](int OperandIdx) {
991	Value *InVal = BdvIE->getOperand(OperandIdx);
992	Value *Base = getBaseForInput(InVal, BaseIE);
993	BaseIE->setOperand(OperandIdx, Base);
994	};
995	UpdateOperand(0); // vector operand
996	UpdateOperand(1); // scalar operand
997	} else {
998	auto *BaseSV = cast<ShuffleVectorInst>(State.getBaseValue());
999	auto *BdvSV = cast<ShuffleVectorInst>(BDV);
1000	auto UpdateOperand = [&](int OperandIdx) {
1001	Value *InVal = BdvSV->getOperand(OperandIdx);
1002	Value *Base = getBaseForInput(InVal, BaseSV);
1003	BaseSV->setOperand(OperandIdx, Base);
	Called C++ object pointer is null
1004	};
1005	UpdateOperand(0); // vector operand
1006	UpdateOperand(1); // vector operand
1007	}
1008	}
1009
1010	// Cache all of our results so we can cheaply reuse them
1011	// NOTE: This is actually two caches: one of the base defining value
1012	// relation and one of the base pointer relation! FIXME
1013	for (auto Pair : States) {
1014	auto *BDV = Pair.first;
1015	Value *Base = Pair.second.getBaseValue();
1016	assert(BDV && Base)((BDV && Base) ? static_cast<void> (0) : __assert_fail ("BDV && Base", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1016, __PRETTY_FUNCTION__));
1017	assert(!isKnownBaseResult(BDV) && "why did it get added?")((!isKnownBaseResult(BDV) && "why did it get added?") ? static_cast<void> (0) : __assert_fail ("!isKnownBaseResult(BDV) && \"why did it get added?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1017, __PRETTY_FUNCTION__));
1018
1019	DEBUG(dbgs() << "Updating base value cache"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "Updating base value cache" << " for: " << BDV->getName() << " from: " << (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none") << " to: " << Base->getName() << "\n"; } } while (false)
1020	<< " for: " << BDV->getName() << " from: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "Updating base value cache" << " for: " << BDV->getName() << " from: " << (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none") << " to: " << Base->getName() << "\n"; } } while (false)
1021	<< (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "Updating base value cache" << " for: " << BDV->getName() << " from: " << (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none") << " to: " << Base->getName() << "\n"; } } while (false)
1022	<< " to: " << Base->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("rewrite-statepoints-for-gc")) { dbgs() << "Updating base value cache" << " for: " << BDV->getName() << " from: " << (Cache.count(BDV) ? Cache[BDV]->getName().str() : "none") << " to: " << Base->getName() << "\n"; } } while (false);
1023
1024	if (Cache.count(BDV)) {
1025	assert(isKnownBaseResult(Base) &&((isKnownBaseResult(Base) && "must be something we 'know' is a base pointer" ) ? static_cast<void> (0) : __assert_fail ("isKnownBaseResult(Base) && \"must be something we 'know' is a base pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1026, __PRETTY_FUNCTION__))
1026	"must be something we 'know' is a base pointer")((isKnownBaseResult(Base) && "must be something we 'know' is a base pointer" ) ? static_cast<void> (0) : __assert_fail ("isKnownBaseResult(Base) && \"must be something we 'know' is a base pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1026, __PRETTY_FUNCTION__));
1027	// Once we transition from the BDV relation being store in the Cache to
1028	// the base relation being stored, it must be stable
1029	assert((!isKnownBaseResult(Cache[BDV]) \|\| Cache[BDV] == Base) &&(((!isKnownBaseResult(Cache[BDV]) \|\| Cache[BDV] == Base) && "base relation should be stable") ? static_cast<void> ( 0) : __assert_fail ("(!isKnownBaseResult(Cache[BDV]) \|\| Cache[BDV] == Base) && \"base relation should be stable\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1030, __PRETTY_FUNCTION__))
1030	"base relation should be stable")(((!isKnownBaseResult(Cache[BDV]) \|\| Cache[BDV] == Base) && "base relation should be stable") ? static_cast<void> ( 0) : __assert_fail ("(!isKnownBaseResult(Cache[BDV]) \|\| Cache[BDV] == Base) && \"base relation should be stable\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1030, __PRETTY_FUNCTION__));
1031	}
1032	Cache[BDV] = Base;
1033	}
1034	assert(Cache.count(Def))((Cache.count(Def)) ? static_cast<void> (0) : __assert_fail ("Cache.count(Def)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1034, __PRETTY_FUNCTION__));
1035	return Cache[Def];
1036	}
1037
1038	// For a set of live pointers (base and/or derived), identify the base
1039	// pointer of the object which they are derived from. This routine will
1040	// mutate the IR graph as needed to make the 'base' pointer live at the
1041	// definition site of 'derived'. This ensures that any use of 'derived' can
1042	// also use 'base'. This may involve the insertion of a number of
1043	// additional PHI nodes.
1044	//
1045	// preconditions: live is a set of pointer type Values
1046	//
1047	// side effects: may insert PHI nodes into the existing CFG, will preserve
1048	// CFG, will not remove or mutate any existing nodes
1049	//
1050	// post condition: PointerToBase contains one (derived, base) pair for every
1051	// pointer in live. Note that derived can be equal to base if the original
1052	// pointer was a base pointer.
1053	static void
1054	findBasePointers(const StatepointLiveSetTy &live,
1055	MapVector<Value , Value > &PointerToBase,
1056	DominatorTree *DT, DefiningValueMapTy &DVCache) {
1057	for (Value *ptr : live) {
1058	Value *base = findBasePointer(ptr, DVCache);
1059	assert(base && "failed to find base pointer")((base && "failed to find base pointer") ? static_cast <void> (0) : __assert_fail ("base && \"failed to find base pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1059, __PRETTY_FUNCTION__));
1060	PointerToBase[ptr] = base;
1061	assert((!isa<Instruction>(base) \|\| !isa<Instruction>(ptr) \|\|(((!isa<Instruction>(base) \|\| !isa<Instruction>(ptr ) \|\| DT->dominates(cast<Instruction>(base)->getParent (), cast<Instruction>(ptr)->getParent())) && "The base we found better dominate the derived pointer") ? static_cast <void> (0) : __assert_fail ("(!isa<Instruction>(base) \|\| !isa<Instruction>(ptr) \|\| DT->dominates(cast<Instruction>(base)->getParent(), cast<Instruction>(ptr)->getParent())) && \"The base we found better dominate the derived pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1064, __PRETTY_FUNCTION__))
1062	DT->dominates(cast<Instruction>(base)->getParent(),(((!isa<Instruction>(base) \|\| !isa<Instruction>(ptr ) \|\| DT->dominates(cast<Instruction>(base)->getParent (), cast<Instruction>(ptr)->getParent())) && "The base we found better dominate the derived pointer") ? static_cast <void> (0) : __assert_fail ("(!isa<Instruction>(base) \|\| !isa<Instruction>(ptr) \|\| DT->dominates(cast<Instruction>(base)->getParent(), cast<Instruction>(ptr)->getParent())) && \"The base we found better dominate the derived pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1064, __PRETTY_FUNCTION__))
1063	cast<Instruction>(ptr)->getParent())) &&(((!isa<Instruction>(base) \|\| !isa<Instruction>(ptr ) \|\| DT->dominates(cast<Instruction>(base)->getParent (), cast<Instruction>(ptr)->getParent())) && "The base we found better dominate the derived pointer") ? static_cast <void> (0) : __assert_fail ("(!isa<Instruction>(base) \|\| !isa<Instruction>(ptr) \|\| DT->dominates(cast<Instruction>(base)->getParent(), cast<Instruction>(ptr)->getParent())) && \"The base we found better dominate the derived pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1064, __PRETTY_FUNCTION__))
1064	"The base we found better dominate the derived pointer")(((!isa<Instruction>(base) \|\| !isa<Instruction>(ptr ) \|\| DT->dominates(cast<Instruction>(base)->getParent (), cast<Instruction>(ptr)->getParent())) && "The base we found better dominate the derived pointer") ? static_cast <void> (0) : __assert_fail ("(!isa<Instruction>(base) \|\| !isa<Instruction>(ptr) \|\| DT->dominates(cast<Instruction>(base)->getParent(), cast<Instruction>(ptr)->getParent())) && \"The base we found better dominate the derived pointer\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1064, __PRETTY_FUNCTION__));
1065	}
1066	}
1067
1068	/// Find the required based pointers (and adjust the live set) for the given
1069	/// parse point.
1070	static void findBasePointers(DominatorTree &DT, DefiningValueMapTy &DVCache,
1071	CallSite CS,
1072	PartiallyConstructedSafepointRecord &result) {
1073	MapVector<Value , Value > PointerToBase;
1074	findBasePointers(result.LiveSet, PointerToBase, &DT, DVCache);
1075
1076	if (PrintBasePointers) {
1077	errs() << "Base Pairs (w/o Relocation):\n";
1078	for (auto &Pair : PointerToBase) {
1079	errs() << " derived ";
1080	Pair.first->printAsOperand(errs(), false);
1081	errs() << " base ";
1082	Pair.second->printAsOperand(errs(), false);
1083	errs() << "\n";;
1084	}
1085	}
1086
1087	result.PointerToBase = PointerToBase;
1088	}
1089
1090	/// Given an updated version of the dataflow liveness results, update the
1091	/// liveset and base pointer maps for the call site CS.
1092	static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
1093	CallSite CS,
1094	PartiallyConstructedSafepointRecord &result);
1095
1096	static void recomputeLiveInValues(
1097	Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
1098	MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
1099	// TODO-PERF: reuse the original liveness, then simply run the dataflow
1100	// again. The old values are still live and will help it stabilize quickly.
1101	GCPtrLivenessData RevisedLivenessData;
1102	computeLiveInValues(DT, F, RevisedLivenessData);
1103	for (size_t i = 0; i < records.size(); i++) {
1104	struct PartiallyConstructedSafepointRecord &info = records[i];
1105	recomputeLiveInValues(RevisedLivenessData, toUpdate[i], info);
1106	}
1107	}
1108
1109	// When inserting gc.relocate and gc.result calls, we need to ensure there are
1110	// no uses of the original value / return value between the gc.statepoint and
1111	// the gc.relocate / gc.result call. One case which can arise is a phi node
1112	// starting one of the successor blocks. We also need to be able to insert the
1113	// gc.relocates only on the path which goes through the statepoint. We might
1114	// need to split an edge to make this possible.
1115	static BasicBlock *
1116	normalizeForInvokeSafepoint(BasicBlock BB, BasicBlock InvokeParent,
1117	DominatorTree &DT) {
1118	BasicBlock *Ret = BB;
1119	if (!BB->getUniquePredecessor())
1120	Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
1121
1122	// Now that 'Ret' has unique predecessor we can safely remove all phi nodes
1123	// from it
1124	FoldSingleEntryPHINodes(Ret);
1125	assert(!isa<PHINode>(Ret->begin()) &&((!isa<PHINode>(Ret->begin()) && "All PHI nodes should have been removed!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(Ret->begin()) && \"All PHI nodes should have been removed!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1126, __PRETTY_FUNCTION__))
1126	"All PHI nodes should have been removed!")((!isa<PHINode>(Ret->begin()) && "All PHI nodes should have been removed!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(Ret->begin()) && \"All PHI nodes should have been removed!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1126, __PRETTY_FUNCTION__));
1127
1128	// At this point, we can safely insert a gc.relocate or gc.result as the first
1129	// instruction in Ret if needed.
1130	return Ret;
1131	}
1132
1133	// Create new attribute set containing only attributes which can be transferred
1134	// from original call to the safepoint.
1135	static AttributeList legalizeCallAttributes(AttributeList AL) {
1136	if (AL.isEmpty())
1137	return AL;
1138
1139	// Remove the readonly, readnone, and statepoint function attributes.
1140	AttrBuilder FnAttrs = AL.getFnAttributes();
1141	FnAttrs.removeAttribute(Attribute::ReadNone);
1142	FnAttrs.removeAttribute(Attribute::ReadOnly);
1143	for (Attribute A : AL.getFnAttributes()) {
1144	if (isStatepointDirectiveAttr(A))
1145	FnAttrs.remove(A);
1146	}
1147
1148	// Just skip parameter and return attributes for now
1149	LLVMContext &Ctx = AL.getContext();
1150	return AttributeList::get(Ctx, AttributeList::FunctionIndex,
1151	AttributeSet::get(Ctx, FnAttrs));
1152	}
1153
1154	/// Helper function to place all gc relocates necessary for the given
1155	/// statepoint.
1156	/// Inputs:
1157	/// liveVariables - list of variables to be relocated.
1158	/// liveStart - index of the first live variable.
1159	/// basePtrs - base pointers.
1160	/// statepointToken - statepoint instruction to which relocates should be
1161	/// bound.
1162	/// Builder - Llvm IR builder to be used to construct new calls.
1163	static void CreateGCRelocates(ArrayRef<Value *> LiveVariables,
1164	const int LiveStart,
1165	ArrayRef<Value *> BasePtrs,
1166	Instruction *StatepointToken,
1167	IRBuilder<> Builder) {
1168	if (LiveVariables.empty())
1169	return;
1170
1171	auto FindIndex = [](ArrayRef<Value > LiveVec, Value Val) {
1172	auto ValIt = find(LiveVec, Val);
1173	assert(ValIt != LiveVec.end() && "Val not found in LiveVec!")((ValIt != LiveVec.end() && "Val not found in LiveVec!" ) ? static_cast<void> (0) : __assert_fail ("ValIt != LiveVec.end() && \"Val not found in LiveVec!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1173, __PRETTY_FUNCTION__));
1174	size_t Index = std::distance(LiveVec.begin(), ValIt);
1175	assert(Index < LiveVec.size() && "Bug in std::find?")((Index < LiveVec.size() && "Bug in std::find?") ? static_cast<void> (0) : __assert_fail ("Index < LiveVec.size() && \"Bug in std::find?\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1175, __PRETTY_FUNCTION__));
1176	return Index;
1177	};
1178	Module *M = StatepointToken->getModule();
1179
1180	// All gc_relocate are generated as i8 addrspace(1)* (or a vector type whose
1181	// element type is i8 addrspace(1)*). We originally generated unique
1182	// declarations for each pointer type, but this proved problematic because
1183	// the intrinsic mangling code is incomplete and fragile. Since we're moving
1184	// towards a single unified pointer type anyways, we can just cast everything
1185	// to an i8* of the right address space. A bitcast is added later to convert
1186	// gc_relocate to the actual value's type.
1187	auto getGCRelocateDecl = [&] (Type *Ty) {
1188	assert(isHandledGCPointerType(Ty))((isHandledGCPointerType(Ty)) ? static_cast<void> (0) : __assert_fail ("isHandledGCPointerType(Ty)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1188, __PRETTY_FUNCTION__));
1189	auto AS = Ty->getScalarType()->getPointerAddressSpace();
1190	Type *NewTy = Type::getInt8PtrTy(M->getContext(), AS);
1191	if (auto *VT = dyn_cast<VectorType>(Ty))
1192	NewTy = VectorType::get(NewTy, VT->getNumElements());
1193	return Intrinsic::getDeclaration(M, Intrinsic::experimental_gc_relocate,
1194	{NewTy});
1195	};
1196
1197	// Lazily populated map from input types to the canonicalized form mentioned
1198	// in the comment above. This should probably be cached somewhere more
1199	// broadly.
1200	DenseMap<Type, Value> TypeToDeclMap;
1201
1202	for (unsigned i = 0; i < LiveVariables.size(); i++) {
1203	// Generate the gc.relocate call and save the result
1204	Value *BaseIdx =
1205	Builder.getInt32(LiveStart + FindIndex(LiveVariables, BasePtrs[i]));
1206	Value *LiveIdx = Builder.getInt32(LiveStart + i);
1207
1208	Type *Ty = LiveVariables[i]->getType();
1209	if (!TypeToDeclMap.count(Ty))
1210	TypeToDeclMap[Ty] = getGCRelocateDecl(Ty);
1211	Value *GCRelocateDecl = TypeToDeclMap[Ty];
1212
1213	// only specify a debug name if we can give a useful one
1214	CallInst *Reloc = Builder.CreateCall(
1215	GCRelocateDecl, {StatepointToken, BaseIdx, LiveIdx},
1216	suffixed_name_or(LiveVariables[i], ".relocated", ""));
1217	// Trick CodeGen into thinking there are lots of free registers at this
1218	// fake call.
1219	Reloc->setCallingConv(CallingConv::Cold);
1220	}
1221	}
1222
1223	namespace {
1224
1225	/// This struct is used to defer RAUWs and `eraseFromParent` s. Using this
1226	/// avoids having to worry about keeping around dangling pointers to Values.
1227	class DeferredReplacement {
1228	AssertingVH<Instruction> Old;
1229	AssertingVH<Instruction> New;
1230	bool IsDeoptimize = false;
1231
1232	DeferredReplacement() {}
1233
1234	public:
1235	static DeferredReplacement createRAUW(Instruction Old, Instruction New) {
1236	assert(Old != New && Old && New &&((Old != New && Old && New && "Cannot RAUW equal values or to / from null!" ) ? static_cast<void> (0) : __assert_fail ("Old != New && Old && New && \"Cannot RAUW equal values or to / from null!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1237, __PRETTY_FUNCTION__))
1237	"Cannot RAUW equal values or to / from null!")((Old != New && Old && New && "Cannot RAUW equal values or to / from null!" ) ? static_cast<void> (0) : __assert_fail ("Old != New && Old && New && \"Cannot RAUW equal values or to / from null!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1237, __PRETTY_FUNCTION__));
1238
1239	DeferredReplacement D;
1240	D.Old = Old;
1241	D.New = New;
1242	return D;
1243	}
1244
1245	static DeferredReplacement createDelete(Instruction *ToErase) {
1246	DeferredReplacement D;
1247	D.Old = ToErase;
1248	return D;
1249	}
1250
1251	static DeferredReplacement createDeoptimizeReplacement(Instruction *Old) {
1252	#ifndef NDEBUG
1253	auto *F = cast<CallInst>(Old)->getCalledFunction();
1254	assert(F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize &&((F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize && "Only way to construct a deoptimize deferred replacement" ) ? static_cast<void> (0) : __assert_fail ("F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize && \"Only way to construct a deoptimize deferred replacement\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1255, __PRETTY_FUNCTION__))
1255	"Only way to construct a deoptimize deferred replacement")((F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize && "Only way to construct a deoptimize deferred replacement" ) ? static_cast<void> (0) : __assert_fail ("F && F->getIntrinsicID() == Intrinsic::experimental_deoptimize && \"Only way to construct a deoptimize deferred replacement\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1255, __PRETTY_FUNCTION__));
1256	#endif
1257	DeferredReplacement D;
1258	D.Old = Old;
1259	D.IsDeoptimize = true;
1260	return D;
1261	}
1262
1263	/// Does the task represented by this instance.
1264	void doReplacement() {
1265	Instruction *OldI = Old;
1266	Instruction *NewI = New;
1267
1268	assert(OldI != NewI && "Disallowed at construction?!")((OldI != NewI && "Disallowed at construction?!") ? static_cast <void> (0) : __assert_fail ("OldI != NewI && \"Disallowed at construction?!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1268, __PRETTY_FUNCTION__));
1269	assert((!IsDeoptimize \|\| !New) &&(((!IsDeoptimize \|\| !New) && "Deoptimize instrinsics are not replaced!" ) ? static_cast<void> (0) : __assert_fail ("(!IsDeoptimize \|\| !New) && \"Deoptimize instrinsics are not replaced!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1270, __PRETTY_FUNCTION__))
1270	"Deoptimize instrinsics are not replaced!")(((!IsDeoptimize \|\| !New) && "Deoptimize instrinsics are not replaced!" ) ? static_cast<void> (0) : __assert_fail ("(!IsDeoptimize \|\| !New) && \"Deoptimize instrinsics are not replaced!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1270, __PRETTY_FUNCTION__));
1271
1272	Old = nullptr;
1273	New = nullptr;
1274
1275	if (NewI)
1276	OldI->replaceAllUsesWith(NewI);
1277
1278	if (IsDeoptimize) {
1279	// Note: we've inserted instructions, so the call to llvm.deoptimize may
1280	// not necessarilly be followed by the matching return.
1281	auto *RI = cast<ReturnInst>(OldI->getParent()->getTerminator());
1282	new UnreachableInst(RI->getContext(), RI);
1283	RI->eraseFromParent();
1284	}
1285
1286	OldI->eraseFromParent();
1287	}
1288	};
1289	}
1290
1291	static StringRef getDeoptLowering(CallSite CS) {
1292	const char *DeoptLowering = "deopt-lowering";
1293	if (CS.hasFnAttr(DeoptLowering)) {
1294	// FIXME: CallSite has a really confusing interface around attributes
1295	// with values.
1296	const AttributeList &CSAS = CS.getAttributes();
1297	if (CSAS.hasAttribute(AttributeList::FunctionIndex, DeoptLowering))
1298	return CSAS.getAttribute(AttributeList::FunctionIndex, DeoptLowering)
1299	.getValueAsString();
1300	Function *F = CS.getCalledFunction();
1301	assert(F && F->hasFnAttribute(DeoptLowering))((F && F->hasFnAttribute(DeoptLowering)) ? static_cast <void> (0) : __assert_fail ("F && F->hasFnAttribute(DeoptLowering)" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1301, __PRETTY_FUNCTION__));
1302	return F->getFnAttribute(DeoptLowering).getValueAsString();
1303	}
1304	return "live-through";
1305	}
1306
1307
1308	static void
1309	makeStatepointExplicitImpl(const CallSite CS, /* to replace */
1310	const SmallVectorImpl<Value *> &BasePtrs,
1311	const SmallVectorImpl<Value *> &LiveVariables,
1312	PartiallyConstructedSafepointRecord &Result,
1313	std::vector<DeferredReplacement> &Replacements) {
1314	assert(BasePtrs.size() == LiveVariables.size())((BasePtrs.size() == LiveVariables.size()) ? static_cast<void > (0) : __assert_fail ("BasePtrs.size() == LiveVariables.size()" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1314, __PRETTY_FUNCTION__));
1315
1316	// Then go ahead and use the builder do actually do the inserts. We insert
1317	// immediately before the previous instruction under the assumption that all
1318	// arguments will be available here. We can't insert afterwards since we may
1319	// be replacing a terminator.
1320	Instruction *InsertBefore = CS.getInstruction();
1321	IRBuilder<> Builder(InsertBefore);
1322
1323	ArrayRef<Value *> GCArgs(LiveVariables);
1324	uint64_t StatepointID = StatepointDirectives::DefaultStatepointID;
1325	uint32_t NumPatchBytes = 0;
1326	uint32_t Flags = uint32_t(StatepointFlags::None);
1327
1328	ArrayRef<Use> CallArgs(CS.arg_begin(), CS.arg_end());
1329	ArrayRef<Use> DeoptArgs = GetDeoptBundleOperands(CS);
1330	ArrayRef<Use> TransitionArgs;
1331	if (auto TransitionBundle =
1332	CS.getOperandBundle(LLVMContext::OB_gc_transition)) {
1333	Flags \|= uint32_t(StatepointFlags::GCTransition);
1334	TransitionArgs = TransitionBundle->Inputs;
1335	}
1336
1337	// Instead of lowering calls to @llvm.experimental.deoptimize as normal calls
1338	// with a return value, we lower then as never returning calls to
1339	// __llvm_deoptimize that are followed by unreachable to get better codegen.
1340	bool IsDeoptimize = false;
1341
1342	StatepointDirectives SD =
1343	parseStatepointDirectivesFromAttrs(CS.getAttributes());
1344	if (SD.NumPatchBytes)
1345	NumPatchBytes = *SD.NumPatchBytes;
1346	if (SD.StatepointID)
1347	StatepointID = *SD.StatepointID;
1348
1349	// Pass through the requested lowering if any. The default is live-through.
1350	StringRef DeoptLowering = getDeoptLowering(CS);
1351	if (DeoptLowering.equals("live-in"))
1352	Flags \|= uint32_t(StatepointFlags::DeoptLiveIn);
1353	else {
1354	assert(DeoptLowering.equals("live-through") && "Unsupported value!")((DeoptLowering.equals("live-through") && "Unsupported value!" ) ? static_cast<void> (0) : __assert_fail ("DeoptLowering.equals(\"live-through\") && \"Unsupported value!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1354, __PRETTY_FUNCTION__));
1355	}
1356
1357	Value *CallTarget = CS.getCalledValue();
1358	if (Function *F = dyn_cast<Function>(CallTarget)) {
1359	if (F->getIntrinsicID() == Intrinsic::experimental_deoptimize) {
1360	// Calls to llvm.experimental.deoptimize are lowered to calls to the
1361	// __llvm_deoptimize symbol. We want to resolve this now, since the
1362	// verifier does not allow taking the address of an intrinsic function.
1363
1364	SmallVector<Type *, 8> DomainTy;
1365	for (Value *Arg : CallArgs)
1366	DomainTy.push_back(Arg->getType());
1367	auto *FTy = FunctionType::get(Type::getVoidTy(F->getContext()), DomainTy,
1368	/* isVarArg = */ false);
1369
1370	// Note: CallTarget can be a bitcast instruction of a symbol if there are
1371	// calls to @llvm.experimental.deoptimize with different argument types in
1372	// the same module. This is fine -- we assume the frontend knew what it
1373	// was doing when generating this kind of IR.
1374	CallTarget =
1375	F->getParent()->getOrInsertFunction("__llvm_deoptimize", FTy);
1376
1377	IsDeoptimize = true;
1378	}
1379	}
1380
1381	// Create the statepoint given all the arguments
1382	Instruction *Token = nullptr;
1383	if (CS.isCall()) {
1384	CallInst *ToReplace = cast<CallInst>(CS.getInstruction());
1385	CallInst *Call = Builder.CreateGCStatepointCall(
1386	StatepointID, NumPatchBytes, CallTarget, Flags, CallArgs,
1387	TransitionArgs, DeoptArgs, GCArgs, "safepoint_token");
1388
1389	Call->setTailCallKind(ToReplace->getTailCallKind());
1390	Call->setCallingConv(ToReplace->getCallingConv());
1391
1392	// Currently we will fail on parameter attributes and on certain
1393	// function attributes. In case if we can handle this set of attributes -
1394	// set up function attrs directly on statepoint and return attrs later for
1395	// gc_result intrinsic.
1396	Call->setAttributes(legalizeCallAttributes(ToReplace->getAttributes()));
1397
1398	Token = Call;
1399
1400	// Put the following gc_result and gc_relocate calls immediately after the
1401	// the old call (which we're about to delete)
1402	assert(ToReplace->getNextNode() && "Not a terminator, must have next!")((ToReplace->getNextNode() && "Not a terminator, must have next!" ) ? static_cast<void> (0) : __assert_fail ("ToReplace->getNextNode() && \"Not a terminator, must have next!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1402, __PRETTY_FUNCTION__));
1403	Builder.SetInsertPoint(ToReplace->getNextNode());
1404	Builder.SetCurrentDebugLocation(ToReplace->getNextNode()->getDebugLoc());
1405	} else {
1406	InvokeInst *ToReplace = cast<InvokeInst>(CS.getInstruction());
1407
1408	// Insert the new invoke into the old block. We'll remove the old one in a
1409	// moment at which point this will become the new terminator for the
1410	// original block.
1411	InvokeInst *Invoke = Builder.CreateGCStatepointInvoke(
1412	StatepointID, NumPatchBytes, CallTarget, ToReplace->getNormalDest(),
1413	ToReplace->getUnwindDest(), Flags, CallArgs, TransitionArgs, DeoptArgs,
1414	GCArgs, "statepoint_token");
1415
1416	Invoke->setCallingConv(ToReplace->getCallingConv());
1417
1418	// Currently we will fail on parameter attributes and on certain
1419	// function attributes. In case if we can handle this set of attributes -
1420	// set up function attrs directly on statepoint and return attrs later for
1421	// gc_result intrinsic.
1422	Invoke->setAttributes(legalizeCallAttributes(ToReplace->getAttributes()));
1423
1424	Token = Invoke;
1425
1426	// Generate gc relocates in exceptional path
1427	BasicBlock *UnwindBlock = ToReplace->getUnwindDest();
1428	assert(!isa<PHINode>(UnwindBlock->begin()) &&((!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1430, __PRETTY_FUNCTION__))
1429	UnwindBlock->getUniquePredecessor() &&((!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1430, __PRETTY_FUNCTION__))
1430	"can't safely insert in this block!")((!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(UnwindBlock->begin()) && UnwindBlock->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1430, __PRETTY_FUNCTION__));
1431
1432	Builder.SetInsertPoint(&*UnwindBlock->getFirstInsertionPt());
1433	Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
1434
1435	// Attach exceptional gc relocates to the landingpad.
1436	Instruction *ExceptionalToken = UnwindBlock->getLandingPadInst();
1437	Result.UnwindToken = ExceptionalToken;
1438
1439	const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1440	CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, ExceptionalToken,
1441	Builder);
1442
1443	// Generate gc relocates and returns for normal block
1444	BasicBlock *NormalDest = ToReplace->getNormalDest();
1445	assert(!isa<PHINode>(NormalDest->begin()) &&((!isa<PHINode>(NormalDest->begin()) && NormalDest ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(NormalDest->begin()) && NormalDest->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1447, __PRETTY_FUNCTION__))
1446	NormalDest->getUniquePredecessor() &&((!isa<PHINode>(NormalDest->begin()) && NormalDest ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(NormalDest->begin()) && NormalDest->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1447, __PRETTY_FUNCTION__))
1447	"can't safely insert in this block!")((!isa<PHINode>(NormalDest->begin()) && NormalDest ->getUniquePredecessor() && "can't safely insert in this block!" ) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(NormalDest->begin()) && NormalDest->getUniquePredecessor() && \"can't safely insert in this block!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1447, __PRETTY_FUNCTION__));
1448
1449	Builder.SetInsertPoint(&*NormalDest->getFirstInsertionPt());
1450
1451	// gc relocates will be generated later as if it were regular call
1452	// statepoint
1453	}
1454	assert(Token && "Should be set in one of the above branches!")((Token && "Should be set in one of the above branches!" ) ? static_cast<void> (0) : __assert_fail ("Token && \"Should be set in one of the above branches!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1454, __PRETTY_FUNCTION__));
1455
1456	if (IsDeoptimize) {
1457	// If we're wrapping an @llvm.experimental.deoptimize in a statepoint, we
1458	// transform the tail-call like structure to a call to a void function
1459	// followed by unreachable to get better codegen.
1460	Replacements.push_back(
1461	DeferredReplacement::createDeoptimizeReplacement(CS.getInstruction()));
1462	} else {
1463	Token->setName("statepoint_token");
1464	if (!CS.getType()->isVoidTy() && !CS.getInstruction()->use_empty()) {
1465	StringRef Name =
1466	CS.getInstruction()->hasName() ? CS.getInstruction()->getName() : "";
1467	CallInst *GCResult = Builder.CreateGCResult(Token, CS.getType(), Name);
1468	GCResult->setAttributes(
1469	AttributeList::get(GCResult->getContext(), AttributeList::ReturnIndex,
1470	CS.getAttributes().getRetAttributes()));
1471
1472	// We cannot RAUW or delete CS.getInstruction() because it could be in the
1473	// live set of some other safepoint, in which case that safepoint's
1474	// PartiallyConstructedSafepointRecord will hold a raw pointer to this
1475	// llvm::Instruction. Instead, we defer the replacement and deletion to
1476	// after the live sets have been made explicit in the IR, and we no longer
1477	// have raw pointers to worry about.
1478	Replacements.emplace_back(
1479	DeferredReplacement::createRAUW(CS.getInstruction(), GCResult));
1480	} else {
1481	Replacements.emplace_back(
1482	DeferredReplacement::createDelete(CS.getInstruction()));
1483	}
1484	}
1485
1486	Result.StatepointToken = Token;
1487
1488	// Second, create a gc.relocate for every live variable
1489	const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1490	CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, Token, Builder);
1491	}
1492
1493	// Replace an existing gc.statepoint with a new one and a set of gc.relocates
1494	// which make the relocations happening at this safepoint explicit.
1495	//
1496	// WARNING: Does not do any fixup to adjust users of the original live
1497	// values. That's the callers responsibility.
1498	static void
1499	makeStatepointExplicit(DominatorTree &DT, CallSite CS,
1500	PartiallyConstructedSafepointRecord &Result,
1501	std::vector<DeferredReplacement> &Replacements) {
1502	const auto &LiveSet = Result.LiveSet;
1503	const auto &PointerToBase = Result.PointerToBase;
1504
1505	// Convert to vector for efficient cross referencing.
1506	SmallVector<Value *, 64> BaseVec, LiveVec;
1507	LiveVec.reserve(LiveSet.size());
1508	BaseVec.reserve(LiveSet.size());
1509	for (Value *L : LiveSet) {
1510	LiveVec.push_back(L);
1511	assert(PointerToBase.count(L))((PointerToBase.count(L)) ? static_cast<void> (0) : __assert_fail ("PointerToBase.count(L)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1511, __PRETTY_FUNCTION__));
1512	Value *Base = PointerToBase.find(L)->second;
1513	BaseVec.push_back(Base);
1514	}
1515	assert(LiveVec.size() == BaseVec.size())((LiveVec.size() == BaseVec.size()) ? static_cast<void> (0) : __assert_fail ("LiveVec.size() == BaseVec.size()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1515, __PRETTY_FUNCTION__));
1516
1517	// Do the actual rewriting and delete the old statepoint
1518	makeStatepointExplicitImpl(CS, BaseVec, LiveVec, Result, Replacements);
1519	}
1520
1521	// Helper function for the relocationViaAlloca.
1522	//
1523	// It receives iterator to the statepoint gc relocates and emits a store to the
1524	// assigned location (via allocaMap) for the each one of them. It adds the
1525	// visited values into the visitedLiveValues set, which we will later use them
1526	// for sanity checking.
1527	static void
1528	insertRelocationStores(iterator_range<Value::user_iterator> GCRelocs,
1529	DenseMap<Value , Value > &AllocaMap,
1530	DenseSet<Value *> &VisitedLiveValues) {
1531
1532	for (User *U : GCRelocs) {
1533	GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U);
1534	if (!Relocate)
1535	continue;
1536
1537	Value *OriginalValue = Relocate->getDerivedPtr();
1538	assert(AllocaMap.count(OriginalValue))((AllocaMap.count(OriginalValue)) ? static_cast<void> ( 0) : __assert_fail ("AllocaMap.count(OriginalValue)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1538, __PRETTY_FUNCTION__));
1539	Value *Alloca = AllocaMap[OriginalValue];
1540
1541	// Emit store into the related alloca
1542	// All gc_relocates are i8 addrspace(1)* typed, and it must be bitcasted to
1543	// the correct type according to alloca.
1544	assert(Relocate->getNextNode() &&((Relocate->getNextNode() && "Should always have one since it's not a terminator" ) ? static_cast<void> (0) : __assert_fail ("Relocate->getNextNode() && \"Should always have one since it's not a terminator\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1545, __PRETTY_FUNCTION__))
1545	"Should always have one since it's not a terminator")((Relocate->getNextNode() && "Should always have one since it's not a terminator" ) ? static_cast<void> (0) : __assert_fail ("Relocate->getNextNode() && \"Should always have one since it's not a terminator\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1545, __PRETTY_FUNCTION__));
1546	IRBuilder<> Builder(Relocate->getNextNode());
1547	Value *CastedRelocatedValue =
1548	Builder.CreateBitCast(Relocate,
1549	cast<AllocaInst>(Alloca)->getAllocatedType(),
1550	suffixed_name_or(Relocate, ".casted", ""));
1551
1552	StoreInst *Store = new StoreInst(CastedRelocatedValue, Alloca);
1553	Store->insertAfter(cast<Instruction>(CastedRelocatedValue));
1554
1555	#ifndef NDEBUG
1556	VisitedLiveValues.insert(OriginalValue);
1557	#endif
1558	}
1559	}
1560
1561	// Helper function for the "relocationViaAlloca". Similar to the
1562	// "insertRelocationStores" but works for rematerialized values.
1563	static void insertRematerializationStores(
1564	const RematerializedValueMapTy &RematerializedValues,
1565	DenseMap<Value , Value > &AllocaMap,
1566	DenseSet<Value *> &VisitedLiveValues) {
1567
1568	for (auto RematerializedValuePair: RematerializedValues) {
1569	Instruction *RematerializedValue = RematerializedValuePair.first;
1570	Value *OriginalValue = RematerializedValuePair.second;
1571
1572	assert(AllocaMap.count(OriginalValue) &&((AllocaMap.count(OriginalValue) && "Can not find alloca for rematerialized value" ) ? static_cast<void> (0) : __assert_fail ("AllocaMap.count(OriginalValue) && \"Can not find alloca for rematerialized value\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1573, __PRETTY_FUNCTION__))
1573	"Can not find alloca for rematerialized value")((AllocaMap.count(OriginalValue) && "Can not find alloca for rematerialized value" ) ? static_cast<void> (0) : __assert_fail ("AllocaMap.count(OriginalValue) && \"Can not find alloca for rematerialized value\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1573, __PRETTY_FUNCTION__));
1574	Value *Alloca = AllocaMap[OriginalValue];
1575
1576	StoreInst *Store = new StoreInst(RematerializedValue, Alloca);
1577	Store->insertAfter(RematerializedValue);
1578
1579	#ifndef NDEBUG
1580	VisitedLiveValues.insert(OriginalValue);
1581	#endif
1582	}
1583	}
1584
1585	/// Do all the relocation update via allocas and mem2reg
1586	static void relocationViaAlloca(
1587	Function &F, DominatorTree &DT, ArrayRef<Value *> Live,
1588	ArrayRef<PartiallyConstructedSafepointRecord> Records) {
1589	#ifndef NDEBUG
1590	// record initial number of (static) allocas; we'll check we have the same
1591	// number when we get done.
1592	int InitialAllocaNum = 0;
1593	for (Instruction &I : F.getEntryBlock())
1594	if (isa<AllocaInst>(I))
1595	InitialAllocaNum++;
1596	#endif
1597
1598	// TODO-PERF: change data structures, reserve
1599	DenseMap<Value , Value > AllocaMap;
1600	SmallVector<AllocaInst *, 200> PromotableAllocas;
1601	// Used later to chack that we have enough allocas to store all values
1602	std::size_t NumRematerializedValues = 0;
1603	PromotableAllocas.reserve(Live.size());
1604
1605	// Emit alloca for "LiveValue" and record it in "allocaMap" and
1606	// "PromotableAllocas"
1607	const DataLayout &DL = F.getParent()->getDataLayout();
1608	auto emitAllocaFor = [&](Value *LiveValue) {
1609	AllocaInst *Alloca = new AllocaInst(LiveValue->getType(),
1610	DL.getAllocaAddrSpace(), "",
1611	F.getEntryBlock().getFirstNonPHI());
1612	AllocaMap[LiveValue] = Alloca;
1613	PromotableAllocas.push_back(Alloca);
1614	};
1615
1616	// Emit alloca for each live gc pointer
1617	for (Value *V : Live)
1618	emitAllocaFor(V);
1619
1620	// Emit allocas for rematerialized values
1621	for (const auto &Info : Records)
1622	for (auto RematerializedValuePair : Info.RematerializedValues) {
1623	Value *OriginalValue = RematerializedValuePair.second;
1624	if (AllocaMap.count(OriginalValue) != 0)
1625	continue;
1626
1627	emitAllocaFor(OriginalValue);
1628	++NumRematerializedValues;
1629	}
1630
1631	// The next two loops are part of the same conceptual operation. We need to
1632	// insert a store to the alloca after the original def and at each
1633	// redefinition. We need to insert a load before each use. These are split
1634	// into distinct loops for performance reasons.
1635
1636	// Update gc pointer after each statepoint: either store a relocated value or
1637	// null (if no relocated value was found for this gc pointer and it is not a
1638	// gc_result). This must happen before we update the statepoint with load of
1639	// alloca otherwise we lose the link between statepoint and old def.
1640	for (const auto &Info : Records) {
1641	Value *Statepoint = Info.StatepointToken;
1642
1643	// This will be used for consistency check
1644	DenseSet<Value *> VisitedLiveValues;
1645
1646	// Insert stores for normal statepoint gc relocates
1647	insertRelocationStores(Statepoint->users(), AllocaMap, VisitedLiveValues);
1648
1649	// In case if it was invoke statepoint
1650	// we will insert stores for exceptional path gc relocates.
1651	if (isa<InvokeInst>(Statepoint)) {
1652	insertRelocationStores(Info.UnwindToken->users(), AllocaMap,
1653	VisitedLiveValues);
1654	}
1655
1656	// Do similar thing with rematerialized values
1657	insertRematerializationStores(Info.RematerializedValues, AllocaMap,
1658	VisitedLiveValues);
1659
1660	if (ClobberNonLive) {
1661	// As a debugging aid, pretend that an unrelocated pointer becomes null at
1662	// the gc.statepoint. This will turn some subtle GC problems into
1663	// slightly easier to debug SEGVs. Note that on large IR files with
1664	// lots of gc.statepoints this is extremely costly both memory and time
1665	// wise.
1666	SmallVector<AllocaInst *, 64> ToClobber;
1667	for (auto Pair : AllocaMap) {
1668	Value *Def = Pair.first;
1669	AllocaInst *Alloca = cast<AllocaInst>(Pair.second);
1670
1671	// This value was relocated
1672	if (VisitedLiveValues.count(Def)) {
1673	continue;
1674	}
1675	ToClobber.push_back(Alloca);
1676	}
1677
1678	auto InsertClobbersAt = [&](Instruction *IP) {
1679	for (auto *AI : ToClobber) {
1680	auto PT = cast<PointerType>(AI->getAllocatedType());
1681	Constant *CPN = ConstantPointerNull::get(PT);
1682	StoreInst *Store = new StoreInst(CPN, AI);
1683	Store->insertBefore(IP);
1684	}
1685	};
1686
1687	// Insert the clobbering stores. These may get intermixed with the
1688	// gc.results and gc.relocates, but that's fine.
1689	if (auto II = dyn_cast<InvokeInst>(Statepoint)) {
1690	InsertClobbersAt(&*II->getNormalDest()->getFirstInsertionPt());
1691	InsertClobbersAt(&*II->getUnwindDest()->getFirstInsertionPt());
1692	} else {
1693	InsertClobbersAt(cast<Instruction>(Statepoint)->getNextNode());
1694	}
1695	}
1696	}
1697
1698	// Update use with load allocas and add store for gc_relocated.
1699	for (auto Pair : AllocaMap) {
1700	Value *Def = Pair.first;
1701	Value *Alloca = Pair.second;
1702
1703	// We pre-record the uses of allocas so that we dont have to worry about
1704	// later update that changes the user information..
1705
1706	SmallVector<Instruction *, 20> Uses;
1707	// PERF: trade a linear scan for repeated reallocation
1708	Uses.reserve(std::distance(Def->user_begin(), Def->user_end()));
1709	for (User *U : Def->users()) {
1710	if (!isa<ConstantExpr>(U)) {
1711	// If the def has a ConstantExpr use, then the def is either a
1712	// ConstantExpr use itself or null. In either case
1713	// (recursively in the first, directly in the second), the oop
1714	// it is ultimately dependent on is null and this particular
1715	// use does not need to be fixed up.
1716	Uses.push_back(cast<Instruction>(U));
1717	}
1718	}
1719
1720	std::sort(Uses.begin(), Uses.end());
1721	auto Last = std::unique(Uses.begin(), Uses.end());
1722	Uses.erase(Last, Uses.end());
1723
1724	for (Instruction *Use : Uses) {
1725	if (isa<PHINode>(Use)) {
1726	PHINode *Phi = cast<PHINode>(Use);
1727	for (unsigned i = 0; i < Phi->getNumIncomingValues(); i++) {
1728	if (Def == Phi->getIncomingValue(i)) {
1729	LoadInst *Load = new LoadInst(
1730	Alloca, "", Phi->getIncomingBlock(i)->getTerminator());
1731	Phi->setIncomingValue(i, Load);
1732	}
1733	}
1734	} else {
1735	LoadInst *Load = new LoadInst(Alloca, "", Use);
1736	Use->replaceUsesOfWith(Def, Load);
1737	}
1738	}
1739
1740	// Emit store for the initial gc value. Store must be inserted after load,
1741	// otherwise store will be in alloca's use list and an extra load will be
1742	// inserted before it.
1743	StoreInst *Store = new StoreInst(Def, Alloca);
1744	if (Instruction *Inst = dyn_cast<Instruction>(Def)) {
1745	if (InvokeInst *Invoke = dyn_cast<InvokeInst>(Inst)) {
1746	// InvokeInst is a TerminatorInst so the store need to be inserted
1747	// into its normal destination block.
1748	BasicBlock *NormalDest = Invoke->getNormalDest();
1749	Store->insertBefore(NormalDest->getFirstNonPHI());
1750	} else {
1751	assert(!Inst->isTerminator() &&((!Inst->isTerminator() && "The only TerminatorInst that can produce a value is " "InvokeInst which is handled above.") ? static_cast<void> (0) : __assert_fail ("!Inst->isTerminator() && \"The only TerminatorInst that can produce a value is \" \"InvokeInst which is handled above.\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1753, __PRETTY_FUNCTION__))
1752	"The only TerminatorInst that can produce a value is "((!Inst->isTerminator() && "The only TerminatorInst that can produce a value is " "InvokeInst which is handled above.") ? static_cast<void> (0) : __assert_fail ("!Inst->isTerminator() && \"The only TerminatorInst that can produce a value is \" \"InvokeInst which is handled above.\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1753, __PRETTY_FUNCTION__))
1753	"InvokeInst which is handled above.")((!Inst->isTerminator() && "The only TerminatorInst that can produce a value is " "InvokeInst which is handled above.") ? static_cast<void> (0) : __assert_fail ("!Inst->isTerminator() && \"The only TerminatorInst that can produce a value is \" \"InvokeInst which is handled above.\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1753, __PRETTY_FUNCTION__));
1754	Store->insertAfter(Inst);
1755	}
1756	} else {
1757	assert(isa<Argument>(Def))((isa<Argument>(Def)) ? static_cast<void> (0) : __assert_fail ("isa<Argument>(Def)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1757, __PRETTY_FUNCTION__));
1758	Store->insertAfter(cast<Instruction>(Alloca));
1759	}
1760	}
1761
1762	assert(PromotableAllocas.size() == Live.size() + NumRematerializedValues &&((PromotableAllocas.size() == Live.size() + NumRematerializedValues && "we must have the same allocas with lives") ? static_cast <void> (0) : __assert_fail ("PromotableAllocas.size() == Live.size() + NumRematerializedValues && \"we must have the same allocas with lives\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1763, __PRETTY_FUNCTION__))
1763	"we must have the same allocas with lives")((PromotableAllocas.size() == Live.size() + NumRematerializedValues && "we must have the same allocas with lives") ? static_cast <void> (0) : __assert_fail ("PromotableAllocas.size() == Live.size() + NumRematerializedValues && \"we must have the same allocas with lives\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1763, __PRETTY_FUNCTION__));
1764	if (!PromotableAllocas.empty()) {
1765	// Apply mem2reg to promote alloca to SSA
1766	PromoteMemToReg(PromotableAllocas, DT);
1767	}
1768
1769	#ifndef NDEBUG
1770	for (auto &I : F.getEntryBlock())
1771	if (isa<AllocaInst>(I))
1772	InitialAllocaNum--;
1773	assert(InitialAllocaNum == 0 && "We must not introduce any extra allocas")((InitialAllocaNum == 0 && "We must not introduce any extra allocas" ) ? static_cast<void> (0) : __assert_fail ("InitialAllocaNum == 0 && \"We must not introduce any extra allocas\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1773, __PRETTY_FUNCTION__));
1774	#endif
1775	}
1776
1777	/// Implement a unique function which doesn't require we sort the input
1778	/// vector. Doing so has the effect of changing the output of a couple of
1779	/// tests in ways which make them less useful in testing fused safepoints.
1780	template <typename T> static void unique_unsorted(SmallVectorImpl<T> &Vec) {
1781	SmallSet<T, 8> Seen;
1782	Vec.erase(remove_if(Vec, [&](const T &V) { return !Seen.insert(V).second; }),
1783	Vec.end());
1784	}
1785
1786	/// Insert holders so that each Value is obviously live through the entire
1787	/// lifetime of the call.
1788	static void insertUseHolderAfter(CallSite &CS, const ArrayRef<Value *> Values,
1789	SmallVectorImpl<CallInst *> &Holders) {
1790	if (Values.empty())
1791	// No values to hold live, might as well not insert the empty holder
1792	return;
1793
1794	Module *M = CS.getInstruction()->getModule();
1795	// Use a dummy vararg function to actually hold the values live
1796	Function *Func = cast<Function>(M->getOrInsertFunction(
1797	"__tmp_use", FunctionType::get(Type::getVoidTy(M->getContext()), true)));
1798	if (CS.isCall()) {
1799	// For call safepoints insert dummy calls right after safepoint
1800	Holders.push_back(CallInst::Create(Func, Values, "",
1801	&*++CS.getInstruction()->getIterator()));
1802	return;
1803	}
1804	// For invoke safepooints insert dummy calls both in normal and
1805	// exceptional destination blocks
1806	auto *II = cast<InvokeInst>(CS.getInstruction());
1807	Holders.push_back(CallInst::Create(
1808	Func, Values, "", &*II->getNormalDest()->getFirstInsertionPt()));
1809	Holders.push_back(CallInst::Create(
1810	Func, Values, "", &*II->getUnwindDest()->getFirstInsertionPt()));
1811	}
1812
1813	static void findLiveReferences(
1814	Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
1815	MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
1816	GCPtrLivenessData OriginalLivenessData;
1817	computeLiveInValues(DT, F, OriginalLivenessData);
1818	for (size_t i = 0; i < records.size(); i++) {
1819	struct PartiallyConstructedSafepointRecord &info = records[i];
1820	analyzeParsePointLiveness(DT, OriginalLivenessData, toUpdate[i], info);
1821	}
1822	}
1823
1824	// Helper function for the "rematerializeLiveValues". It walks use chain
1825	// starting from the "CurrentValue" until it reaches the root of the chain, i.e.
1826	// the base or a value it cannot process. Only "simple" values are processed
1827	// (currently it is GEP's and casts). The returned root is examined by the
1828	// callers of findRematerializableChainToBasePointer. Fills "ChainToBase" array
1829	// with all visited values.
1830	static Value* findRematerializableChainToBasePointer(
1831	SmallVectorImpl<Instruction*> &ChainToBase,
1832	Value *CurrentValue) {
1833
1834	if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(CurrentValue)) {
1835	ChainToBase.push_back(GEP);
1836	return findRematerializableChainToBasePointer(ChainToBase,
1837	GEP->getPointerOperand());
1838	}
1839
1840	if (CastInst *CI = dyn_cast<CastInst>(CurrentValue)) {
1841	if (!CI->isNoopCast(CI->getModule()->getDataLayout()))
1842	return CI;
1843
1844	ChainToBase.push_back(CI);
1845	return findRematerializableChainToBasePointer(ChainToBase,
1846	CI->getOperand(0));
1847	}
1848
1849	// We have reached the root of the chain, which is either equal to the base or
1850	// is the first unsupported value along the use chain.
1851	return CurrentValue;
1852	}
1853
1854	// Helper function for the "rematerializeLiveValues". Compute cost of the use
1855	// chain we are going to rematerialize.
1856	static unsigned
1857	chainToBasePointerCost(SmallVectorImpl<Instruction*> &Chain,
1858	TargetTransformInfo &TTI) {
1859	unsigned Cost = 0;
1860
1861	for (Instruction *Instr : Chain) {
1862	if (CastInst *CI = dyn_cast<CastInst>(Instr)) {
1863	assert(CI->isNoopCast(CI->getModule()->getDataLayout()) &&((CI->isNoopCast(CI->getModule()->getDataLayout()) && "non noop cast is found during rematerialization") ? static_cast <void> (0) : __assert_fail ("CI->isNoopCast(CI->getModule()->getDataLayout()) && \"non noop cast is found during rematerialization\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1864, __PRETTY_FUNCTION__))
1864	"non noop cast is found during rematerialization")((CI->isNoopCast(CI->getModule()->getDataLayout()) && "non noop cast is found during rematerialization") ? static_cast <void> (0) : __assert_fail ("CI->isNoopCast(CI->getModule()->getDataLayout()) && \"non noop cast is found during rematerialization\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1864, __PRETTY_FUNCTION__));
1865
1866	Type *SrcTy = CI->getOperand(0)->getType();
1867	Cost += TTI.getCastInstrCost(CI->getOpcode(), CI->getType(), SrcTy, CI);
1868
1869	} else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Instr)) {
1870	// Cost of the address calculation
1871	Type *ValTy = GEP->getSourceElementType();
1872	Cost += TTI.getAddressComputationCost(ValTy);
1873
1874	// And cost of the GEP itself
1875	// TODO: Use TTI->getGEPCost here (it exists, but appears to be not
1876	// allowed for the external usage)
1877	if (!GEP->hasAllConstantIndices())
1878	Cost += 2;
1879
1880	} else {
1881	llvm_unreachable("unsupported instruciton type during rematerialization")::llvm::llvm_unreachable_internal("unsupported instruciton type during rematerialization" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1881);
1882	}
1883	}
1884
1885	return Cost;
1886	}
1887
1888	static bool AreEquivalentPhiNodes(PHINode &OrigRootPhi, PHINode &AlternateRootPhi) {
1889
1890	unsigned PhiNum = OrigRootPhi.getNumIncomingValues();
1891	if (PhiNum != AlternateRootPhi.getNumIncomingValues() \|\|
1892	OrigRootPhi.getParent() != AlternateRootPhi.getParent())
1893	return false;
1894	// Map of incoming values and their corresponding basic blocks of
1895	// OrigRootPhi.
1896	SmallDenseMap<Value , BasicBlock , 8> CurrentIncomingValues;
1897	for (unsigned i = 0; i < PhiNum; i++)
1898	CurrentIncomingValues[OrigRootPhi.getIncomingValue(i)] =
1899	OrigRootPhi.getIncomingBlock(i);
1900
1901	// Both current and base PHIs should have same incoming values and
1902	// the same basic blocks corresponding to the incoming values.
1903	for (unsigned i = 0; i < PhiNum; i++) {
1904	auto CIVI =
1905	CurrentIncomingValues.find(AlternateRootPhi.getIncomingValue(i));
1906	if (CIVI == CurrentIncomingValues.end())
1907	return false;
1908	BasicBlock *CurrentIncomingBB = CIVI->second;
1909	if (CurrentIncomingBB != AlternateRootPhi.getIncomingBlock(i))
1910	return false;
1911	}
1912	return true;
1913
1914	}
1915
1916	// From the statepoint live set pick values that are cheaper to recompute then
1917	// to relocate. Remove this values from the live set, rematerialize them after
1918	// statepoint and record them in "Info" structure. Note that similar to
1919	// relocated values we don't do any user adjustments here.
1920	static void rematerializeLiveValues(CallSite CS,
1921	PartiallyConstructedSafepointRecord &Info,
1922	TargetTransformInfo &TTI) {
1923	const unsigned int ChainLengthThreshold = 10;
1924
1925	// Record values we are going to delete from this statepoint live set.
1926	// We can not di this in following loop due to iterator invalidation.
1927	SmallVector<Value *, 32> LiveValuesToBeDeleted;
1928
1929	for (Value *LiveValue: Info.LiveSet) {
1930	// For each live pointer find it's defining chain
1931	SmallVector<Instruction *, 3> ChainToBase;
1932	assert(Info.PointerToBase.count(LiveValue))((Info.PointerToBase.count(LiveValue)) ? static_cast<void> (0) : __assert_fail ("Info.PointerToBase.count(LiveValue)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1932, __PRETTY_FUNCTION__));
1933	Value *RootOfChain =
1934	findRematerializableChainToBasePointer(ChainToBase,
1935	LiveValue);
1936
1937	// Nothing to do, or chain is too long
1938	if ( ChainToBase.size() == 0 \|\|
1939	ChainToBase.size() > ChainLengthThreshold)
1940	continue;
1941
1942	// Handle the scenario where the RootOfChain is not equal to the
1943	// Base Value, but they are essentially the same phi values.
1944	if (RootOfChain != Info.PointerToBase[LiveValue]) {
1945	PHINode *OrigRootPhi = dyn_cast<PHINode>(RootOfChain);
1946	PHINode *AlternateRootPhi = dyn_cast<PHINode>(Info.PointerToBase[LiveValue]);
1947	if (!OrigRootPhi \|\| !AlternateRootPhi)
1948	continue;
1949	// PHI nodes that have the same incoming values, and belonging to the same
1950	// basic blocks are essentially the same SSA value. When the original phi
1951	// has incoming values with different base pointers, the original phi is
1952	// marked as conflict, and an additional `AlternateRootPhi` with the same
1953	// incoming values get generated by the findBasePointer function. We need
1954	// to identify the newly generated AlternateRootPhi (.base version of phi)
1955	// and RootOfChain (the original phi node itself) are the same, so that we
1956	// can rematerialize the gep and casts. This is a workaround for the
1957	// deficieny in the findBasePointer algorithm.
1958	if (!AreEquivalentPhiNodes(OrigRootPhi, AlternateRootPhi))
1959	continue;
1960	// Now that the phi nodes are proved to be the same, assert that
1961	// findBasePointer's newly generated AlternateRootPhi is present in the
1962	// liveset of the call.
1963	assert(Info.LiveSet.count(AlternateRootPhi))((Info.LiveSet.count(AlternateRootPhi)) ? static_cast<void > (0) : __assert_fail ("Info.LiveSet.count(AlternateRootPhi)" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 1963, __PRETTY_FUNCTION__));
1964	}
1965	// Compute cost of this chain
1966	unsigned Cost = chainToBasePointerCost(ChainToBase, TTI);
1967	// TODO: We can also account for cases when we will be able to remove some
1968	// of the rematerialized values by later optimization passes. I.e if
1969	// we rematerialized several intersecting chains. Or if original values
1970	// don't have any uses besides this statepoint.
1971
1972	// For invokes we need to rematerialize each chain twice - for normal and
1973	// for unwind basic blocks. Model this by multiplying cost by two.
1974	if (CS.isInvoke()) {
1975	Cost *= 2;
1976	}
1977	// If it's too expensive - skip it
1978	if (Cost >= RematerializationThreshold)
1979	continue;
1980
1981	// Remove value from the live set
1982	LiveValuesToBeDeleted.push_back(LiveValue);
1983
1984	// Clone instructions and record them inside "Info" structure
1985
1986	// Walk backwards to visit top-most instructions first
1987	std::reverse(ChainToBase.begin(), ChainToBase.end());
1988
1989	// Utility function which clones all instructions from "ChainToBase"
1990	// and inserts them before "InsertBefore". Returns rematerialized value
1991	// which should be used after statepoint.
1992	auto rematerializeChain = [&ChainToBase](
1993	Instruction InsertBefore, Value RootOfChain, Value *AlternateLiveBase) {
1994	Instruction *LastClonedValue = nullptr;
1995	Instruction *LastValue = nullptr;
1996	for (Instruction *Instr: ChainToBase) {
1997	// Only GEP's and casts are suported as we need to be careful to not
1998	// introduce any new uses of pointers not in the liveset.
1999	// Note that it's fine to introduce new uses of pointers which were
2000	// otherwise not used after this statepoint.
2001	assert(isa<GetElementPtrInst>(Instr) \|\| isa<CastInst>(Instr))((isa<GetElementPtrInst>(Instr) \|\| isa<CastInst>( Instr)) ? static_cast<void> (0) : __assert_fail ("isa<GetElementPtrInst>(Instr) \|\| isa<CastInst>(Instr)" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2001, __PRETTY_FUNCTION__));
2002
2003	Instruction *ClonedValue = Instr->clone();
2004	ClonedValue->insertBefore(InsertBefore);
2005	ClonedValue->setName(Instr->getName() + ".remat");
2006
2007	// If it is not first instruction in the chain then it uses previously
2008	// cloned value. We should update it to use cloned value.
2009	if (LastClonedValue) {
2010	assert(LastValue)((LastValue) ? static_cast<void> (0) : __assert_fail ("LastValue" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2010, __PRETTY_FUNCTION__));
2011	ClonedValue->replaceUsesOfWith(LastValue, LastClonedValue);
2012	#ifndef NDEBUG
2013	for (auto OpValue : ClonedValue->operand_values()) {
2014	// Assert that cloned instruction does not use any instructions from
2015	// this chain other than LastClonedValue
2016	assert(!is_contained(ChainToBase, OpValue) &&((!is_contained(ChainToBase, OpValue) && "incorrect use in rematerialization chain" ) ? static_cast<void> (0) : __assert_fail ("!is_contained(ChainToBase, OpValue) && \"incorrect use in rematerialization chain\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2017, __PRETTY_FUNCTION__))
2017	"incorrect use in rematerialization chain")((!is_contained(ChainToBase, OpValue) && "incorrect use in rematerialization chain" ) ? static_cast<void> (0) : __assert_fail ("!is_contained(ChainToBase, OpValue) && \"incorrect use in rematerialization chain\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2017, __PRETTY_FUNCTION__));
2018	// Assert that the cloned instruction does not use the RootOfChain
2019	// or the AlternateLiveBase.
2020	assert(OpValue != RootOfChain && OpValue != AlternateLiveBase)((OpValue != RootOfChain && OpValue != AlternateLiveBase ) ? static_cast<void> (0) : __assert_fail ("OpValue != RootOfChain && OpValue != AlternateLiveBase" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2020, __PRETTY_FUNCTION__));
2021	}
2022	#endif
2023	} else {
2024	// For the first instruction, replace the use of unrelocated base i.e.
2025	// RootOfChain/OrigRootPhi, with the corresponding PHI present in the
2026	// live set. They have been proved to be the same PHI nodes. Note
2027	// that the only use of the RootOfChain in the ChainToBase list is
2028	// the first Value in the list.
2029	if (RootOfChain != AlternateLiveBase)
2030	ClonedValue->replaceUsesOfWith(RootOfChain, AlternateLiveBase);
2031	}
2032
2033	LastClonedValue = ClonedValue;
2034	LastValue = Instr;
2035	}
2036	assert(LastClonedValue)((LastClonedValue) ? static_cast<void> (0) : __assert_fail ("LastClonedValue", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2036, __PRETTY_FUNCTION__));
2037	return LastClonedValue;
2038	};
2039
2040	// Different cases for calls and invokes. For invokes we need to clone
2041	// instructions both on normal and unwind path.
2042	if (CS.isCall()) {
2043	Instruction *InsertBefore = CS.getInstruction()->getNextNode();
2044	assert(InsertBefore)((InsertBefore) ? static_cast<void> (0) : __assert_fail ("InsertBefore", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2044, __PRETTY_FUNCTION__));
2045	Instruction *RematerializedValue = rematerializeChain(
2046	InsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2047	Info.RematerializedValues[RematerializedValue] = LiveValue;
2048	} else {
2049	InvokeInst *Invoke = cast<InvokeInst>(CS.getInstruction());
2050
2051	Instruction *NormalInsertBefore =
2052	&*Invoke->getNormalDest()->getFirstInsertionPt();
2053	Instruction *UnwindInsertBefore =
2054	&*Invoke->getUnwindDest()->getFirstInsertionPt();
2055
2056	Instruction *NormalRematerializedValue = rematerializeChain(
2057	NormalInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2058	Instruction *UnwindRematerializedValue = rematerializeChain(
2059	UnwindInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2060
2061	Info.RematerializedValues[NormalRematerializedValue] = LiveValue;
2062	Info.RematerializedValues[UnwindRematerializedValue] = LiveValue;
2063	}
2064	}
2065
2066	// Remove rematerializaed values from the live set
2067	for (auto LiveValue: LiveValuesToBeDeleted) {
2068	Info.LiveSet.remove(LiveValue);
2069	}
2070	}
2071
2072	static bool insertParsePoints(Function &F, DominatorTree &DT,
2073	TargetTransformInfo &TTI,
2074	SmallVectorImpl<CallSite> &ToUpdate) {
2075	#ifndef NDEBUG
2076	// sanity check the input
2077	std::set<CallSite> Uniqued;
2078	Uniqued.insert(ToUpdate.begin(), ToUpdate.end());
2079	assert(Uniqued.size() == ToUpdate.size() && "no duplicates please!")((Uniqued.size() == ToUpdate.size() && "no duplicates please!" ) ? static_cast<void> (0) : __assert_fail ("Uniqued.size() == ToUpdate.size() && \"no duplicates please!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2079, __PRETTY_FUNCTION__));
2080
2081	for (CallSite CS : ToUpdate)
2082	assert(CS.getInstruction()->getFunction() == &F)((CS.getInstruction()->getFunction() == &F) ? static_cast <void> (0) : __assert_fail ("CS.getInstruction()->getFunction() == &F" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2082, __PRETTY_FUNCTION__));
2083	#endif
2084
2085	// When inserting gc.relocates for invokes, we need to be able to insert at
2086	// the top of the successor blocks. See the comment on
2087	// normalForInvokeSafepoint on exactly what is needed. Note that this step
2088	// may restructure the CFG.
2089	for (CallSite CS : ToUpdate) {
2090	if (!CS.isInvoke())
2091	continue;
2092	auto *II = cast<InvokeInst>(CS.getInstruction());
2093	normalizeForInvokeSafepoint(II->getNormalDest(), II->getParent(), DT);
2094	normalizeForInvokeSafepoint(II->getUnwindDest(), II->getParent(), DT);
2095	}
2096
2097	// A list of dummy calls added to the IR to keep various values obviously
2098	// live in the IR. We'll remove all of these when done.
2099	SmallVector<CallInst *, 64> Holders;
2100
2101	// Insert a dummy call with all of the deopt operands we'll need for the
2102	// actual safepoint insertion as arguments. This ensures reference operands
2103	// in the deopt argument list are considered live through the safepoint (and
2104	// thus makes sure they get relocated.)
2105	for (CallSite CS : ToUpdate) {
2106	SmallVector<Value *, 64> DeoptValues;
2107
2108	for (Value *Arg : GetDeoptBundleOperands(CS)) {
2109	assert(!isUnhandledGCPointerType(Arg->getType()) &&((!isUnhandledGCPointerType(Arg->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(Arg->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2110, __PRETTY_FUNCTION__))
2110	"support for FCA unimplemented")((!isUnhandledGCPointerType(Arg->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(Arg->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2110, __PRETTY_FUNCTION__));
2111	if (isHandledGCPointerType(Arg->getType()))
2112	DeoptValues.push_back(Arg);
2113	}
2114
2115	insertUseHolderAfter(CS, DeoptValues, Holders);
2116	}
2117
2118	SmallVector<PartiallyConstructedSafepointRecord, 64> Records(ToUpdate.size());
2119
2120	// A) Identify all gc pointers which are statically live at the given call
2121	// site.
2122	findLiveReferences(F, DT, ToUpdate, Records);
2123
2124	// B) Find the base pointers for each live pointer
2125	/* scope for caching */ {
2126	// Cache the 'defining value' relation used in the computation and
2127	// insertion of base phis and selects. This ensures that we don't insert
2128	// large numbers of duplicate base_phis.
2129	DefiningValueMapTy DVCache;
2130
2131	for (size_t i = 0; i < Records.size(); i++) {
2132	PartiallyConstructedSafepointRecord &info = Records[i];
2133	findBasePointers(DT, DVCache, ToUpdate[i], info);
2134	}
2135	} // end of cache scope
2136
2137	// The base phi insertion logic (for any safepoint) may have inserted new
2138	// instructions which are now live at some safepoint. The simplest such
2139	// example is:
2140	// loop:
2141	// phi a <-- will be a new base_phi here
2142	// safepoint 1 <-- that needs to be live here
2143	// gep a + 1
2144	// safepoint 2
2145	// br loop
2146	// We insert some dummy calls after each safepoint to definitely hold live
2147	// the base pointers which were identified for that safepoint. We'll then
2148	// ask liveness for _every_ base inserted to see what is now live. Then we
2149	// remove the dummy calls.
2150	Holders.reserve(Holders.size() + Records.size());
2151	for (size_t i = 0; i < Records.size(); i++) {
2152	PartiallyConstructedSafepointRecord &Info = Records[i];
2153
2154	SmallVector<Value *, 128> Bases;
2155	for (auto Pair : Info.PointerToBase)
2156	Bases.push_back(Pair.second);
2157
2158	insertUseHolderAfter(ToUpdate[i], Bases, Holders);
2159	}
2160
2161	// By selecting base pointers, we've effectively inserted new uses. Thus, we
2162	// need to rerun liveness. We may also have inserted new defs, but that's
2163	// not the key issue.
2164	recomputeLiveInValues(F, DT, ToUpdate, Records);
2165
2166	if (PrintBasePointers) {
2167	for (auto &Info : Records) {
2168	errs() << "Base Pairs: (w/Relocation)\n";
2169	for (auto Pair : Info.PointerToBase) {
2170	errs() << " derived ";
2171	Pair.first->printAsOperand(errs(), false);
2172	errs() << " base ";
2173	Pair.second->printAsOperand(errs(), false);
2174	errs() << "\n";
2175	}
2176	}
2177	}
2178
2179	// It is possible that non-constant live variables have a constant base. For
2180	// example, a GEP with a variable offset from a global. In this case we can
2181	// remove it from the liveset. We already don't add constants to the liveset
2182	// because we assume they won't move at runtime and the GC doesn't need to be
2183	// informed about them. The same reasoning applies if the base is constant.
2184	// Note that the relocation placement code relies on this filtering for
2185	// correctness as it expects the base to be in the liveset, which isn't true
2186	// if the base is constant.
2187	for (auto &Info : Records)
2188	for (auto &BasePair : Info.PointerToBase)
2189	if (isa<Constant>(BasePair.second))
2190	Info.LiveSet.remove(BasePair.first);
2191
2192	for (CallInst *CI : Holders)
2193	CI->eraseFromParent();
2194
2195	Holders.clear();
2196
2197	// In order to reduce live set of statepoint we might choose to rematerialize
2198	// some values instead of relocating them. This is purely an optimization and
2199	// does not influence correctness.
2200	for (size_t i = 0; i < Records.size(); i++)
2201	rematerializeLiveValues(ToUpdate[i], Records[i], TTI);
2202
2203	// We need this to safely RAUW and delete call or invoke return values that
2204	// may themselves be live over a statepoint. For details, please see usage in
2205	// makeStatepointExplicitImpl.
2206	std::vector<DeferredReplacement> Replacements;
2207
2208	// Now run through and replace the existing statepoints with new ones with
2209	// the live variables listed. We do not yet update uses of the values being
2210	// relocated. We have references to live variables that need to
2211	// survive to the last iteration of this loop. (By construction, the
2212	// previous statepoint can not be a live variable, thus we can and remove
2213	// the old statepoint calls as we go.)
2214	for (size_t i = 0; i < Records.size(); i++)
2215	makeStatepointExplicit(DT, ToUpdate[i], Records[i], Replacements);
2216
2217	ToUpdate.clear(); // prevent accident use of invalid CallSites
2218
2219	for (auto &PR : Replacements)
2220	PR.doReplacement();
2221
2222	Replacements.clear();
2223
2224	for (auto &Info : Records) {
2225	// These live sets may contain state Value pointers, since we replaced calls
2226	// with operand bundles with calls wrapped in gc.statepoint, and some of
2227	// those calls may have been def'ing live gc pointers. Clear these out to
2228	// avoid accidentally using them.
2229	//
2230	// TODO: We should create a separate data structure that does not contain
2231	// these live sets, and migrate to using that data structure from this point
2232	// onward.
2233	Info.LiveSet.clear();
2234	Info.PointerToBase.clear();
2235	}
2236
2237	// Do all the fixups of the original live variables to their relocated selves
2238	SmallVector<Value *, 128> Live;
2239	for (size_t i = 0; i < Records.size(); i++) {
2240	PartiallyConstructedSafepointRecord &Info = Records[i];
2241
2242	// We can't simply save the live set from the original insertion. One of
2243	// the live values might be the result of a call which needs a safepoint.
2244	// That Value* no longer exists and we need to use the new gc_result.
2245	// Thankfully, the live set is embedded in the statepoint (and updated), so
2246	// we just grab that.
2247	Statepoint Statepoint(Info.StatepointToken);
2248	Live.insert(Live.end(), Statepoint.gc_args_begin(),
2249	Statepoint.gc_args_end());
2250	#ifndef NDEBUG
2251	// Do some basic sanity checks on our liveness results before performing
2252	// relocation. Relocation can and will turn mistakes in liveness results
2253	// into non-sensical code which is must harder to debug.
2254	// TODO: It would be nice to test consistency as well
2255	assert(DT.isReachableFromEntry(Info.StatepointToken->getParent()) &&((DT.isReachableFromEntry(Info.StatepointToken->getParent( )) && "statepoint must be reachable or liveness is meaningless" ) ? static_cast<void> (0) : __assert_fail ("DT.isReachableFromEntry(Info.StatepointToken->getParent()) && \"statepoint must be reachable or liveness is meaningless\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2256, __PRETTY_FUNCTION__))
2256	"statepoint must be reachable or liveness is meaningless")((DT.isReachableFromEntry(Info.StatepointToken->getParent( )) && "statepoint must be reachable or liveness is meaningless" ) ? static_cast<void> (0) : __assert_fail ("DT.isReachableFromEntry(Info.StatepointToken->getParent()) && \"statepoint must be reachable or liveness is meaningless\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2256, __PRETTY_FUNCTION__));
2257	for (Value *V : Statepoint.gc_args()) {
2258	if (!isa<Instruction>(V))
2259	// Non-instruction values trivial dominate all possible uses
2260	continue;
2261	auto *LiveInst = cast<Instruction>(V);
2262	assert(DT.isReachableFromEntry(LiveInst->getParent()) &&((DT.isReachableFromEntry(LiveInst->getParent()) && "unreachable values should never be live") ? static_cast< void> (0) : __assert_fail ("DT.isReachableFromEntry(LiveInst->getParent()) && \"unreachable values should never be live\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2263, __PRETTY_FUNCTION__))
2263	"unreachable values should never be live")((DT.isReachableFromEntry(LiveInst->getParent()) && "unreachable values should never be live") ? static_cast< void> (0) : __assert_fail ("DT.isReachableFromEntry(LiveInst->getParent()) && \"unreachable values should never be live\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2263, __PRETTY_FUNCTION__));
2264	assert(DT.dominates(LiveInst, Info.StatepointToken) &&((DT.dominates(LiveInst, Info.StatepointToken) && "basic SSA liveness expectation violated by liveness analysis" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(LiveInst, Info.StatepointToken) && \"basic SSA liveness expectation violated by liveness analysis\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2265, __PRETTY_FUNCTION__))
2265	"basic SSA liveness expectation violated by liveness analysis")((DT.dominates(LiveInst, Info.StatepointToken) && "basic SSA liveness expectation violated by liveness analysis" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(LiveInst, Info.StatepointToken) && \"basic SSA liveness expectation violated by liveness analysis\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2265, __PRETTY_FUNCTION__));
2266	}
2267	#endif
2268	}
2269	unique_unsorted(Live);
2270
2271	#ifndef NDEBUG
2272	// sanity check
2273	for (auto *Ptr : Live)
2274	assert(isHandledGCPointerType(Ptr->getType()) &&((isHandledGCPointerType(Ptr->getType()) && "must be a gc pointer type" ) ? static_cast<void> (0) : __assert_fail ("isHandledGCPointerType(Ptr->getType()) && \"must be a gc pointer type\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2275, __PRETTY_FUNCTION__))
2275	"must be a gc pointer type")((isHandledGCPointerType(Ptr->getType()) && "must be a gc pointer type" ) ? static_cast<void> (0) : __assert_fail ("isHandledGCPointerType(Ptr->getType()) && \"must be a gc pointer type\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2275, __PRETTY_FUNCTION__));
2276	#endif
2277
2278	relocationViaAlloca(F, DT, Live, Records);
2279	return !Records.empty();
2280	}
2281
2282	// Handles both return values and arguments for Functions and CallSites.
2283	template <typename AttrHolder>
2284	static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
2285	unsigned Index) {
2286	AttrBuilder R;
2287	if (AH.getDereferenceableBytes(Index))
2288	R.addAttribute(Attribute::get(Ctx, Attribute::Dereferenceable,
2289	AH.getDereferenceableBytes(Index)));
2290	if (AH.getDereferenceableOrNullBytes(Index))
2291	R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull,
2292	AH.getDereferenceableOrNullBytes(Index)));
2293	if (AH.getAttributes().hasAttribute(Index, Attribute::NoAlias))
2294	R.addAttribute(Attribute::NoAlias);
2295
2296	if (!R.empty())
2297	AH.setAttributes(AH.getAttributes().removeAttributes(Ctx, Index, R));
2298	}
2299
2300	void
2301	RewriteStatepointsForGC::stripNonValidAttributesFromPrototype(Function &F) {
2302	LLVMContext &Ctx = F.getContext();
2303
2304	for (Argument &A : F.args())
2305	if (isa<PointerType>(A.getType()))
2306	RemoveNonValidAttrAtIndex(Ctx, F,
2307	A.getArgNo() + AttributeList::FirstArgIndex);
2308
2309	if (isa<PointerType>(F.getReturnType()))
2310	RemoveNonValidAttrAtIndex(Ctx, F, AttributeList::ReturnIndex);
2311	}
2312
2313	void RewriteStatepointsForGC::stripInvalidMetadataFromInstruction(Instruction &I) {
2314
2315	if (!isa<LoadInst>(I) && !isa<StoreInst>(I))
2316	return;
2317	// These are the attributes that are still valid on loads and stores after
2318	// RS4GC.
2319	// The metadata implying dereferenceability and noalias are (conservatively)
2320	// dropped. This is because semantically, after RewriteStatepointsForGC runs,
2321	// all calls to gc.statepoint "free" the entire heap. Also, gc.statepoint can
2322	// touch the entire heap including noalias objects. Note: The reasoning is
2323	// same as stripping the dereferenceability and noalias attributes that are
2324	// analogous to the metadata counterparts.
2325	// We also drop the invariant.load metadata on the load because that metadata
2326	// implies the address operand to the load points to memory that is never
2327	// changed once it became dereferenceable. This is no longer true after RS4GC.
2328	// Similar reasoning applies to invariant.group metadata, which applies to
2329	// loads within a group.
2330	unsigned ValidMetadataAfterRS4GC[] = {LLVMContext::MD_tbaa,
2331	LLVMContext::MD_range,
2332	LLVMContext::MD_alias_scope,
2333	LLVMContext::MD_nontemporal,
2334	LLVMContext::MD_nonnull,
2335	LLVMContext::MD_align,
2336	LLVMContext::MD_type};
2337
2338	// Drops all metadata on the instruction other than ValidMetadataAfterRS4GC.
2339	I.dropUnknownNonDebugMetadata(ValidMetadataAfterRS4GC);
2340
2341	}
2342
2343	void RewriteStatepointsForGC::stripNonValidAttributesAndMetadataFromBody(Function &F) {
2344	if (F.empty())
2345	return;
2346
2347	LLVMContext &Ctx = F.getContext();
2348	MDBuilder Builder(Ctx);
2349
2350
2351	for (Instruction &I : instructions(F)) {
2352	if (const MDNode *MD = I.getMetadata(LLVMContext::MD_tbaa)) {
2353	assert(MD->getNumOperands() < 5 && "unrecognized metadata shape!")((MD->getNumOperands() < 5 && "unrecognized metadata shape!" ) ? static_cast<void> (0) : __assert_fail ("MD->getNumOperands() < 5 && \"unrecognized metadata shape!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2353, __PRETTY_FUNCTION__));
2354	bool IsImmutableTBAA =
2355	MD->getNumOperands() == 4 &&
2356	mdconst::extract<ConstantInt>(MD->getOperand(3))->getValue() == 1;
2357
2358	if (!IsImmutableTBAA)
2359	continue; // no work to do, MD_tbaa is already marked mutable
2360
2361	MDNode *Base = cast<MDNode>(MD->getOperand(0));
2362	MDNode *Access = cast<MDNode>(MD->getOperand(1));
2363	uint64_t Offset =
2364	mdconst::extract<ConstantInt>(MD->getOperand(2))->getZExtValue();
2365
2366	MDNode *MutableTBAA =
2367	Builder.createTBAAStructTagNode(Base, Access, Offset);
2368	I.setMetadata(LLVMContext::MD_tbaa, MutableTBAA);
2369	}
2370
2371	stripInvalidMetadataFromInstruction(I);
2372
2373	if (CallSite CS = CallSite(&I)) {
2374	for (int i = 0, e = CS.arg_size(); i != e; i++)
2375	if (isa<PointerType>(CS.getArgument(i)->getType()))
2376	RemoveNonValidAttrAtIndex(Ctx, CS, i + AttributeList::FirstArgIndex);
2377	if (isa<PointerType>(CS.getType()))
2378	RemoveNonValidAttrAtIndex(Ctx, CS, AttributeList::ReturnIndex);
2379	}
2380	}
2381	}
2382
2383	/// Returns true if this function should be rewritten by this pass. The main
2384	/// point of this function is as an extension point for custom logic.
2385	static bool shouldRewriteStatepointsIn(Function &F) {
2386	// TODO: This should check the GCStrategy
2387	if (F.hasGC()) {
2388	const auto &FunctionGCName = F.getGC();
2389	const StringRef StatepointExampleName("statepoint-example");
2390	const StringRef CoreCLRName("coreclr");
2391	return (StatepointExampleName == FunctionGCName) \|\|
2392	(CoreCLRName == FunctionGCName);
2393	} else
2394	return false;
2395	}
2396
2397	void RewriteStatepointsForGC::stripNonValidAttributesAndMetadata(Module &M) {
2398	#ifndef NDEBUG
2399	assert(any_of(M, shouldRewriteStatepointsIn) && "precondition!")((any_of(M, shouldRewriteStatepointsIn) && "precondition!" ) ? static_cast<void> (0) : __assert_fail ("any_of(M, shouldRewriteStatepointsIn) && \"precondition!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2399, __PRETTY_FUNCTION__));
2400	#endif
2401
2402	for (Function &F : M)
2403	stripNonValidAttributesFromPrototype(F);
2404
2405	for (Function &F : M)
2406	stripNonValidAttributesAndMetadataFromBody(F);
2407	}
2408
2409	bool RewriteStatepointsForGC::runOnFunction(Function &F) {
2410	// Nothing to do for declarations.
2411	if (F.isDeclaration() \|\| F.empty())
2412	return false;
2413
2414	// Policy choice says not to rewrite - the most common reason is that we're
2415	// compiling code without a GCStrategy.
2416	if (!shouldRewriteStatepointsIn(F))
2417	return false;
2418
2419	DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
2420	TargetTransformInfo &TTI =
2421	getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
2422
2423	auto NeedsRewrite = [](Instruction &I) {
2424	if (ImmutableCallSite CS = ImmutableCallSite(&I))
2425	return !callsGCLeafFunction(CS) && !isStatepoint(CS);
2426	return false;
2427	};
2428
2429	// Gather all the statepoints which need rewritten. Be careful to only
2430	// consider those in reachable code since we need to ask dominance queries
2431	// when rewriting. We'll delete the unreachable ones in a moment.
2432	SmallVector<CallSite, 64> ParsePointNeeded;
2433	bool HasUnreachableStatepoint = false;
2434	for (Instruction &I : instructions(F)) {
2435	// TODO: only the ones with the flag set!
2436	if (NeedsRewrite(I)) {
2437	if (DT.isReachableFromEntry(I.getParent()))
2438	ParsePointNeeded.push_back(CallSite(&I));
2439	else
2440	HasUnreachableStatepoint = true;
2441	}
2442	}
2443
2444	bool MadeChange = false;
2445
2446	// Delete any unreachable statepoints so that we don't have unrewritten
2447	// statepoints surviving this pass. This makes testing easier and the
2448	// resulting IR less confusing to human readers. Rather than be fancy, we
2449	// just reuse a utility function which removes the unreachable blocks.
2450	if (HasUnreachableStatepoint)
2451	MadeChange \|= removeUnreachableBlocks(F);
2452
2453	// Return early if no work to do.
2454	if (ParsePointNeeded.empty())
2455	return MadeChange;
2456
2457	// As a prepass, go ahead and aggressively destroy single entry phi nodes.
2458	// These are created by LCSSA. They have the effect of increasing the size
2459	// of liveness sets for no good reason. It may be harder to do this post
2460	// insertion since relocations and base phis can confuse things.
2461	for (BasicBlock &BB : F)
2462	if (BB.getUniquePredecessor()) {
2463	MadeChange = true;
2464	FoldSingleEntryPHINodes(&BB);
2465	}
2466
2467	// Before we start introducing relocations, we want to tweak the IR a bit to
2468	// avoid unfortunate code generation effects. The main example is that we
2469	// want to try to make sure the comparison feeding a branch is after any
2470	// safepoints. Otherwise, we end up with a comparison of pre-relocation
2471	// values feeding a branch after relocation. This is semantically correct,
2472	// but results in extra register pressure since both the pre-relocation and
2473	// post-relocation copies must be available in registers. For code without
2474	// relocations this is handled elsewhere, but teaching the scheduler to
2475	// reverse the transform we're about to do would be slightly complex.
2476	// Note: This may extend the live range of the inputs to the icmp and thus
2477	// increase the liveset of any statepoint we move over. This is profitable
2478	// as long as all statepoints are in rare blocks. If we had in-register
2479	// lowering for live values this would be a much safer transform.
2480	auto getConditionInst = [](TerminatorInst TI) -> Instruction {
2481	if (auto *BI = dyn_cast<BranchInst>(TI))
2482	if (BI->isConditional())
2483	return dyn_cast<Instruction>(BI->getCondition());
2484	// TODO: Extend this to handle switches
2485	return nullptr;
2486	};
2487	for (BasicBlock &BB : F) {
2488	TerminatorInst *TI = BB.getTerminator();
2489	if (auto *Cond = getConditionInst(TI))
2490	// TODO: Handle more than just ICmps here. We should be able to move
2491	// most instructions without side effects or memory access.
2492	if (isa<ICmpInst>(Cond) && Cond->hasOneUse()) {
2493	MadeChange = true;
2494	Cond->moveBefore(TI);
2495	}
2496	}
2497
2498	MadeChange \|= insertParsePoints(F, DT, TTI, ParsePointNeeded);
2499	return MadeChange;
2500	}
2501
2502	// liveness computation via standard dataflow
2503	// -------------------------------------------------------------------
2504
2505	// TODO: Consider using bitvectors for liveness, the set of potentially
2506	// interesting values should be small and easy to pre-compute.
2507
2508	/// Compute the live-in set for the location rbegin starting from
2509	/// the live-out set of the basic block
2510	static void computeLiveInValues(BasicBlock::reverse_iterator Begin,
2511	BasicBlock::reverse_iterator End,
2512	SetVector<Value *> &LiveTmp) {
2513	for (auto &I : make_range(Begin, End)) {
2514	// KILL/Def - Remove this definition from LiveIn
2515	LiveTmp.remove(&I);
2516
2517	// Don't consider uses in PHI nodes, we handle their contribution to
2518	// predecessor blocks when we seed the LiveOut sets
2519	if (isa<PHINode>(I))
2520	continue;
2521
2522	// USE - Add to the LiveIn set for this instruction
2523	for (Value *V : I.operands()) {
2524	assert(!isUnhandledGCPointerType(V->getType()) &&((!isUnhandledGCPointerType(V->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(V->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2525, __PRETTY_FUNCTION__))
2525	"support for FCA unimplemented")((!isUnhandledGCPointerType(V->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(V->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2525, __PRETTY_FUNCTION__));
2526	if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V)) {
2527	// The choice to exclude all things constant here is slightly subtle.
2528	// There are two independent reasons:
2529	// - We assume that things which are constant (from LLVM's definition)
2530	// do not move at runtime. For example, the address of a global
2531	// variable is fixed, even though it's contents may not be.
2532	// - Second, we can't disallow arbitrary inttoptr constants even
2533	// if the language frontend does. Optimization passes are free to
2534	// locally exploit facts without respect to global reachability. This
2535	// can create sections of code which are dynamically unreachable and
2536	// contain just about anything. (see constants.ll in tests)
2537	LiveTmp.insert(V);
2538	}
2539	}
2540	}
2541	}
2542
2543	static void computeLiveOutSeed(BasicBlock BB, SetVector<Value > &LiveTmp) {
2544	for (BasicBlock *Succ : successors(BB)) {
2545	for (auto &I : *Succ) {
2546	PHINode *PN = dyn_cast<PHINode>(&I);
2547	if (!PN)
2548	break;
2549
2550	Value *V = PN->getIncomingValueForBlock(BB);
2551	assert(!isUnhandledGCPointerType(V->getType()) &&((!isUnhandledGCPointerType(V->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(V->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2552, __PRETTY_FUNCTION__))
2552	"support for FCA unimplemented")((!isUnhandledGCPointerType(V->getType()) && "support for FCA unimplemented" ) ? static_cast<void> (0) : __assert_fail ("!isUnhandledGCPointerType(V->getType()) && \"support for FCA unimplemented\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2552, __PRETTY_FUNCTION__));
2553	if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V))
2554	LiveTmp.insert(V);
2555	}
2556	}
2557	}
2558
2559	static SetVector<Value > computeKillSet(BasicBlock BB) {
2560	SetVector<Value *> KillSet;
2561	for (Instruction &I : *BB)
2562	if (isHandledGCPointerType(I.getType()))
2563	KillSet.insert(&I);
2564	return KillSet;
2565	}
2566
2567	#ifndef NDEBUG
2568	/// Check that the items in 'Live' dominate 'TI'. This is used as a basic
2569	/// sanity check for the liveness computation.
2570	static void checkBasicSSA(DominatorTree &DT, SetVector<Value *> &Live,
2571	TerminatorInst *TI, bool TermOkay = false) {
2572	for (Value *V : Live) {
2573	if (auto *I = dyn_cast<Instruction>(V)) {
2574	// The terminator can be a member of the LiveOut set. LLVM's definition
2575	// of instruction dominance states that V does not dominate itself. As
2576	// such, we need to special case this to allow it.
2577	if (TermOkay && TI == I)
2578	continue;
2579	assert(DT.dominates(I, TI) &&((DT.dominates(I, TI) && "basic SSA liveness expectation violated by liveness analysis" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(I, TI) && \"basic SSA liveness expectation violated by liveness analysis\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2580, __PRETTY_FUNCTION__))
2580	"basic SSA liveness expectation violated by liveness analysis")((DT.dominates(I, TI) && "basic SSA liveness expectation violated by liveness analysis" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(I, TI) && \"basic SSA liveness expectation violated by liveness analysis\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2580, __PRETTY_FUNCTION__));
2581	}
2582	}
2583	}
2584
2585	/// Check that all the liveness sets used during the computation of liveness
2586	/// obey basic SSA properties. This is useful for finding cases where we miss
2587	/// a def.
2588	static void checkBasicSSA(DominatorTree &DT, GCPtrLivenessData &Data,
2589	BasicBlock &BB) {
2590	checkBasicSSA(DT, Data.LiveSet[&BB], BB.getTerminator());
2591	checkBasicSSA(DT, Data.LiveOut[&BB], BB.getTerminator(), true);
2592	checkBasicSSA(DT, Data.LiveIn[&BB], BB.getTerminator());
2593	}
2594	#endif
2595
2596	static void computeLiveInValues(DominatorTree &DT, Function &F,
2597	GCPtrLivenessData &Data) {
2598	SmallSetVector<BasicBlock *, 32> Worklist;
2599
2600	// Seed the liveness for each individual block
2601	for (BasicBlock &BB : F) {
2602	Data.KillSet[&BB] = computeKillSet(&BB);
2603	Data.LiveSet[&BB].clear();
2604	computeLiveInValues(BB.rbegin(), BB.rend(), Data.LiveSet[&BB]);
2605
2606	#ifndef NDEBUG
2607	for (Value *Kill : Data.KillSet[&BB])
2608	assert(!Data.LiveSet[&BB].count(Kill) && "live set contains kill")((!Data.LiveSet[&BB].count(Kill) && "live set contains kill" ) ? static_cast<void> (0) : __assert_fail ("!Data.LiveSet[&BB].count(Kill) && \"live set contains kill\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2608, __PRETTY_FUNCTION__));
2609	#endif
2610
2611	Data.LiveOut[&BB] = SetVector<Value *>();
2612	computeLiveOutSeed(&BB, Data.LiveOut[&BB]);
2613	Data.LiveIn[&BB] = Data.LiveSet[&BB];
2614	Data.LiveIn[&BB].set_union(Data.LiveOut[&BB]);
2615	Data.LiveIn[&BB].set_subtract(Data.KillSet[&BB]);
2616	if (!Data.LiveIn[&BB].empty())
2617	Worklist.insert(pred_begin(&BB), pred_end(&BB));
2618	}
2619
2620	// Propagate that liveness until stable
2621	while (!Worklist.empty()) {
2622	BasicBlock *BB = Worklist.pop_back_val();
2623
2624	// Compute our new liveout set, then exit early if it hasn't changed despite
2625	// the contribution of our successor.
2626	SetVector<Value *> LiveOut = Data.LiveOut[BB];
2627	const auto OldLiveOutSize = LiveOut.size();
2628	for (BasicBlock *Succ : successors(BB)) {
2629	assert(Data.LiveIn.count(Succ))((Data.LiveIn.count(Succ)) ? static_cast<void> (0) : __assert_fail ("Data.LiveIn.count(Succ)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2629, __PRETTY_FUNCTION__));
2630	LiveOut.set_union(Data.LiveIn[Succ]);
2631	}
2632	// assert OutLiveOut is a subset of LiveOut
2633	if (OldLiveOutSize == LiveOut.size()) {
2634	// If the sets are the same size, then we didn't actually add anything
2635	// when unioning our successors LiveIn. Thus, the LiveIn of this block
2636	// hasn't changed.
2637	continue;
2638	}
2639	Data.LiveOut[BB] = LiveOut;
2640
2641	// Apply the effects of this basic block
2642	SetVector<Value *> LiveTmp = LiveOut;
2643	LiveTmp.set_union(Data.LiveSet[BB]);
2644	LiveTmp.set_subtract(Data.KillSet[BB]);
2645
2646	assert(Data.LiveIn.count(BB))((Data.LiveIn.count(BB)) ? static_cast<void> (0) : __assert_fail ("Data.LiveIn.count(BB)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2646, __PRETTY_FUNCTION__));
2647	const SetVector<Value *> &OldLiveIn = Data.LiveIn[BB];
2648	// assert: OldLiveIn is a subset of LiveTmp
2649	if (OldLiveIn.size() != LiveTmp.size()) {
2650	Data.LiveIn[BB] = LiveTmp;
2651	Worklist.insert(pred_begin(BB), pred_end(BB));
2652	}
2653	} // while (!Worklist.empty())
2654
2655	#ifndef NDEBUG
2656	// Sanity check our output against SSA properties. This helps catch any
2657	// missing kills during the above iteration.
2658	for (BasicBlock &BB : F)
2659	checkBasicSSA(DT, Data, BB);
2660	#endif
2661	}
2662
2663	static void findLiveSetAtInst(Instruction *Inst, GCPtrLivenessData &Data,
2664	StatepointLiveSetTy &Out) {
2665
2666	BasicBlock *BB = Inst->getParent();
2667
2668	// Note: The copy is intentional and required
2669	assert(Data.LiveOut.count(BB))((Data.LiveOut.count(BB)) ? static_cast<void> (0) : __assert_fail ("Data.LiveOut.count(BB)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2669, __PRETTY_FUNCTION__));
2670	SetVector<Value *> LiveOut = Data.LiveOut[BB];
2671
2672	// We want to handle the statepoint itself oddly. It's
2673	// call result is not live (normal), nor are it's arguments
2674	// (unless they're used again later). This adjustment is
2675	// specifically what we need to relocate
2676	computeLiveInValues(BB->rbegin(), ++Inst->getIterator().getReverse(),
2677	LiveOut);
2678	LiveOut.remove(Inst);
2679	Out.insert(LiveOut.begin(), LiveOut.end());
2680	}
2681
2682	static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
2683	CallSite CS,
2684	PartiallyConstructedSafepointRecord &Info) {
2685	Instruction *Inst = CS.getInstruction();
2686	StatepointLiveSetTy Updated;
2687	findLiveSetAtInst(Inst, RevisedLivenessData, Updated);
2688
2689	#ifndef NDEBUG
2690	DenseSet<Value *> Bases;
2691	for (auto KVPair : Info.PointerToBase)
2692	Bases.insert(KVPair.second);
2693	#endif
2694
2695	// We may have base pointers which are now live that weren't before. We need
2696	// to update the PointerToBase structure to reflect this.
2697	for (auto V : Updated)
2698	if (Info.PointerToBase.insert({V, V}).second) {
2699	assert(Bases.count(V) && "Can't find base for unexpected live value!")((Bases.count(V) && "Can't find base for unexpected live value!" ) ? static_cast<void> (0) : __assert_fail ("Bases.count(V) && \"Can't find base for unexpected live value!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2699, __PRETTY_FUNCTION__));
2700	continue;
2701	}
2702
2703	#ifndef NDEBUG
2704	for (auto V : Updated)
2705	assert(Info.PointerToBase.count(V) &&((Info.PointerToBase.count(V) && "Must be able to find base for live value!" ) ? static_cast<void> (0) : __assert_fail ("Info.PointerToBase.count(V) && \"Must be able to find base for live value!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2706, __PRETTY_FUNCTION__))
2706	"Must be able to find base for live value!")((Info.PointerToBase.count(V) && "Must be able to find base for live value!" ) ? static_cast<void> (0) : __assert_fail ("Info.PointerToBase.count(V) && \"Must be able to find base for live value!\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2706, __PRETTY_FUNCTION__));
2707	#endif
2708
2709	// Remove any stale base mappings - this can happen since our liveness is
2710	// more precise then the one inherent in the base pointer analysis.
2711	DenseSet<Value *> ToErase;
2712	for (auto KVPair : Info.PointerToBase)
2713	if (!Updated.count(KVPair.first))
2714	ToErase.insert(KVPair.first);
2715
2716	for (auto *V : ToErase)
2717	Info.PointerToBase.erase(V);
2718
2719	#ifndef NDEBUG
2720	for (auto KVPair : Info.PointerToBase)
2721	assert(Updated.count(KVPair.first) && "record for non-live value")((Updated.count(KVPair.first) && "record for non-live value" ) ? static_cast<void> (0) : __assert_fail ("Updated.count(KVPair.first) && \"record for non-live value\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp" , 2721, __PRETTY_FUNCTION__));
2722	#endif
2723
2724	Info.LiveSet = Updated;
2725	}