Bug Summary

File:lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
Warning:line 989, 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 an existing set of gc.statepoints such that they make potential
11// relocations performed by the garbage collector explicit in the IR.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Pass.h"
16#include "llvm/Analysis/CFG.h"
17#include "llvm/Analysis/TargetTransformInfo.h"
18#include "llvm/ADT/SetOperations.h"
19#include "llvm/ADT/Statistic.h"
20#include "llvm/ADT/DenseSet.h"
21#include "llvm/ADT/SetVector.h"
22#include "llvm/ADT/StringRef.h"
23#include "llvm/ADT/MapVector.h"
24#include "llvm/IR/BasicBlock.h"
25#include "llvm/IR/CallSite.h"
26#include "llvm/IR/Dominators.h"
27#include "llvm/IR/Function.h"
28#include "llvm/IR/IRBuilder.h"
29#include "llvm/IR/InstIterator.h"
30#include "llvm/IR/Instructions.h"
31#include "llvm/IR/Intrinsics.h"
32#include "llvm/IR/IntrinsicInst.h"
33#include "llvm/IR/Module.h"
34#include "llvm/IR/MDBuilder.h"
35#include "llvm/IR/Statepoint.h"
36#include "llvm/IR/Value.h"
37#include "llvm/IR/Verifier.h"
38#include "llvm/Support/Debug.h"
39#include "llvm/Support/CommandLine.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
48using namespace llvm;
49
50// Print the liveset found at the insert location
51static cl::opt<bool> PrintLiveSet("spp-print-liveset", cl::Hidden,
52 cl::init(false));
53static cl::opt<bool> PrintLiveSetSize("spp-print-liveset-size", cl::Hidden,
54 cl::init(false));
55// Print out the base pointers for debugging
56static 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
61static cl::opt<unsigned>
62RematerializationThreshold("spp-rematerialization-threshold", cl::Hidden,
63 cl::init(6));
64
65#ifdef EXPENSIVE_CHECKS
66static bool ClobberNonLive = true;
67#else
68static bool ClobberNonLive = false;
69#endif
70static cl::opt<bool, true> ClobberNonLiveOverride("rs4gc-clobber-non-live",
71 cl::location(ClobberNonLive),
72 cl::Hidden);
73
74static cl::opt<bool>
75 AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info",
76 cl::Hidden, cl::init(true));
77
78namespace {
79struct 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 // stripNonValidAttributes 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 stripNonValidAttributes(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 implying
109 /// 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. stripNonValidAttributes (conservatively) restores correctness
113 /// by erasing all attributes in the module that externally imply
114 /// dereferenceability.
115 /// Similar reasoning also applies to the noalias attributes. gc.statepoint
116 /// can touch the entire heap including noalias objects.
117 void stripNonValidAttributes(Module &M);
118
119 // Helpers for stripNonValidAttributes
120 void stripNonValidAttributesFromBody(Function &F);
121 void stripNonValidAttributesFromPrototype(Function &F);
122};
123} // namespace
124
125char RewriteStatepointsForGC::ID = 0;
126
127ModulePass *llvm::createRewriteStatepointsForGCPass() {
128 return new RewriteStatepointsForGC();
129}
130
131INITIALIZE_PASS_BEGIN(RewriteStatepointsForGC, "rewrite-statepoints-for-gc",static void *initializeRewriteStatepointsForGCPassOnce(PassRegistry
&Registry) {
132 "Make relocations explicit at statepoints", false, false)static void *initializeRewriteStatepointsForGCPassOnce(PassRegistry
&Registry) {
133INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
134INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
135INITIALIZE_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
)); }
136 "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
)); }
137
138namespace {
139struct GCPtrLivenessData {
140 /// Values defined in this block.
141 MapVector<BasicBlock *, SetVector<Value *>> KillSet;
142 /// Values used in this block (and thus live); does not included values
143 /// killed within this block.
144 MapVector<BasicBlock *, SetVector<Value *>> LiveSet;
145
146 /// Values live into this basic block (i.e. used by any
147 /// instruction in this basic block or ones reachable from here)
148 MapVector<BasicBlock *, SetVector<Value *>> LiveIn;
149
150 /// Values live out of this basic block (i.e. live into
151 /// any successor block)
152 MapVector<BasicBlock *, SetVector<Value *>> LiveOut;
153};
154
155// The type of the internal cache used inside the findBasePointers family
156// of functions. From the callers perspective, this is an opaque type and
157// should not be inspected.
158//
159// In the actual implementation this caches two relations:
160// - The base relation itself (i.e. this pointer is based on that one)
161// - The base defining value relation (i.e. before base_phi insertion)
162// Generally, after the execution of a full findBasePointer call, only the
163// base relation will remain. Internally, we add a mixture of the two
164// types, then update all the second type to the first type
165typedef MapVector<Value *, Value *> DefiningValueMapTy;
166typedef SetVector<Value *> StatepointLiveSetTy;
167typedef MapVector<AssertingVH<Instruction>, AssertingVH<Value>>
168 RematerializedValueMapTy;
169
170struct PartiallyConstructedSafepointRecord {
171 /// The set of values known to be live across this safepoint
172 StatepointLiveSetTy LiveSet;
173
174 /// Mapping from live pointers to a base-defining-value
175 MapVector<Value *, Value *> PointerToBase;
176
177 /// The *new* gc.statepoint instruction itself. This produces the token
178 /// that normal path gc.relocates and the gc.result are tied to.
179 Instruction *StatepointToken;
180
181 /// Instruction to which exceptional gc relocates are attached
182 /// Makes it easier to iterate through them during relocationViaAlloca.
183 Instruction *UnwindToken;
184
185 /// Record live values we are rematerialized instead of relocating.
186 /// They are not included into 'LiveSet' field.
187 /// Maps rematerialized copy to it's original value.
188 RematerializedValueMapTy RematerializedValues;
189};
190}
191
192static ArrayRef<Use> GetDeoptBundleOperands(ImmutableCallSite CS) {
193 Optional<OperandBundleUse> DeoptBundle =
194 CS.getOperandBundle(LLVMContext::OB_deopt);
195
196 if (!DeoptBundle.hasValue()) {
197 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 198, __PRETTY_FUNCTION__))
198 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 198, __PRETTY_FUNCTION__))
;
199 return None;
200 }
201
202 return DeoptBundle.getValue().Inputs;
203}
204
205/// Compute the live-in set for every basic block in the function
206static void computeLiveInValues(DominatorTree &DT, Function &F,
207 GCPtrLivenessData &Data);
208
209/// Given results from the dataflow liveness computation, find the set of live
210/// Values at a particular instruction.
211static void findLiveSetAtInst(Instruction *inst, GCPtrLivenessData &Data,
212 StatepointLiveSetTy &out);
213
214// TODO: Once we can get to the GCStrategy, this becomes
215// Optional<bool> isGCManagedPointer(const Type *Ty) const override {
216
217static bool isGCPointerType(Type *T) {
218 if (auto *PT = dyn_cast<PointerType>(T))
219 // For the sake of this example GC, we arbitrarily pick addrspace(1) as our
220 // GC managed heap. We know that a pointer into this heap needs to be
221 // updated and that no other pointer does.
222 return PT->getAddressSpace() == 1;
223 return false;
224}
225
226// Return true if this type is one which a) is a gc pointer or contains a GC
227// pointer and b) is of a type this code expects to encounter as a live value.
228// (The insertion code will assert that a type which matches (a) and not (b)
229// is not encountered.)
230static bool isHandledGCPointerType(Type *T) {
231 // We fully support gc pointers
232 if (isGCPointerType(T))
233 return true;
234 // We partially support vectors of gc pointers. The code will assert if it
235 // can't handle something.
236 if (auto VT = dyn_cast<VectorType>(T))
237 if (isGCPointerType(VT->getElementType()))
238 return true;
239 return false;
240}
241
242#ifndef NDEBUG
243/// Returns true if this type contains a gc pointer whether we know how to
244/// handle that type or not.
245static bool containsGCPtrType(Type *Ty) {
246 if (isGCPointerType(Ty))
247 return true;
248 if (VectorType *VT = dyn_cast<VectorType>(Ty))
249 return isGCPointerType(VT->getScalarType());
250 if (ArrayType *AT = dyn_cast<ArrayType>(Ty))
251 return containsGCPtrType(AT->getElementType());
252 if (StructType *ST = dyn_cast<StructType>(Ty))
253 return any_of(ST->subtypes(), containsGCPtrType);
254 return false;
255}
256
257// Returns true if this is a type which a) is a gc pointer or contains a GC
258// pointer and b) is of a type which the code doesn't expect (i.e. first class
259// aggregates). Used to trip assertions.
260static bool isUnhandledGCPointerType(Type *Ty) {
261 return containsGCPtrType(Ty) && !isHandledGCPointerType(Ty);
262}
263#endif
264
265// Return the name of the value suffixed with the provided value, or if the
266// value didn't have a name, the default value specified.
267static std::string suffixed_name_or(Value *V, StringRef Suffix,
268 StringRef DefaultName) {
269 return V->hasName() ? (V->getName() + Suffix).str() : DefaultName.str();
270}
271
272// Conservatively identifies any definitions which might be live at the
273// given instruction. The analysis is performed immediately before the
274// given instruction. Values defined by that instruction are not considered
275// live. Values used by that instruction are considered live.
276static void
277analyzeParsePointLiveness(DominatorTree &DT,
278 GCPtrLivenessData &OriginalLivenessData, CallSite CS,
279 PartiallyConstructedSafepointRecord &Result) {
280 Instruction *Inst = CS.getInstruction();
281
282 StatepointLiveSetTy LiveSet;
283 findLiveSetAtInst(Inst, OriginalLivenessData, LiveSet);
284
285 if (PrintLiveSet) {
286 dbgs() << "Live Variables:\n";
287 for (Value *V : LiveSet)
288 dbgs() << " " << V->getName() << " " << *V << "\n";
289 }
290 if (PrintLiveSetSize) {
291 dbgs() << "Safepoint For: " << CS.getCalledValue()->getName() << "\n";
292 dbgs() << "Number live values: " << LiveSet.size() << "\n";
293 }
294 Result.LiveSet = LiveSet;
295}
296
297static bool isKnownBaseResult(Value *V);
298namespace {
299/// A single base defining value - An immediate base defining value for an
300/// instruction 'Def' is an input to 'Def' whose base is also a base of 'Def'.
301/// For instructions which have multiple pointer [vector] inputs or that
302/// transition between vector and scalar types, there is no immediate base
303/// defining value. The 'base defining value' for 'Def' is the transitive
304/// closure of this relation stopping at the first instruction which has no
305/// immediate base defining value. The b.d.v. might itself be a base pointer,
306/// but it can also be an arbitrary derived pointer.
307struct BaseDefiningValueResult {
308 /// Contains the value which is the base defining value.
309 Value * const BDV;
310 /// True if the base defining value is also known to be an actual base
311 /// pointer.
312 const bool IsKnownBase;
313 BaseDefiningValueResult(Value *BDV, bool IsKnownBase)
314 : BDV(BDV), IsKnownBase(IsKnownBase) {
315#ifndef NDEBUG
316 // Check consistency between new and old means of checking whether a BDV is
317 // a base.
318 bool MustBeBase = isKnownBaseResult(BDV);
319 assert(!MustBeBase || MustBeBase == IsKnownBase)((!MustBeBase || MustBeBase == IsKnownBase) ? static_cast<
void> (0) : __assert_fail ("!MustBeBase || MustBeBase == IsKnownBase"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 319, __PRETTY_FUNCTION__))
;
320#endif
321 }
322};
323}
324
325static BaseDefiningValueResult findBaseDefiningValue(Value *I);
326
327/// Return a base defining value for the 'Index' element of the given vector
328/// instruction 'I'. If Index is null, returns a BDV for the entire vector
329/// 'I'. As an optimization, this method will try to determine when the
330/// element is known to already be a base pointer. If this can be established,
331/// the second value in the returned pair will be true. Note that either a
332/// vector or a pointer typed value can be returned. For the former, the
333/// vector returned is a BDV (and possibly a base) of the entire vector 'I'.
334/// If the later, the return pointer is a BDV (or possibly a base) for the
335/// particular element in 'I'.
336static BaseDefiningValueResult
337findBaseDefiningValueOfVector(Value *I) {
338 // Each case parallels findBaseDefiningValue below, see that code for
339 // detailed motivation.
340
341 if (isa<Argument>(I))
342 // An incoming argument to the function is a base pointer
343 return BaseDefiningValueResult(I, true);
344
345 if (isa<Constant>(I))
346 // Base of constant vector consists only of constant null pointers.
347 // For reasoning see similar case inside 'findBaseDefiningValue' function.
348 return BaseDefiningValueResult(ConstantAggregateZero::get(I->getType()),
349 true);
350
351 if (isa<LoadInst>(I))
352 return BaseDefiningValueResult(I, true);
353
354 if (isa<InsertElementInst>(I))
355 // We don't know whether this vector contains entirely base pointers or
356 // not. To be conservatively correct, we treat it as a BDV and will
357 // duplicate code as needed to construct a parallel vector of bases.
358 return BaseDefiningValueResult(I, false);
359
360 if (isa<ShuffleVectorInst>(I))
361 // We don't know whether this vector contains entirely base pointers or
362 // not. To be conservatively correct, we treat it as a BDV and will
363 // duplicate code as needed to construct a parallel vector of bases.
364 // TODO: There a number of local optimizations which could be applied here
365 // for particular sufflevector patterns.
366 return BaseDefiningValueResult(I, false);
367
368 // The behavior of getelementptr instructions is the same for vector and
369 // non-vector data types.
370 if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
371 return findBaseDefiningValue(GEP->getPointerOperand());
372
373 // A PHI or Select is a base defining value. The outer findBasePointer
374 // algorithm is responsible for constructing a base value for this BDV.
375 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 376, __PRETTY_FUNCTION__))
376 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 376, __PRETTY_FUNCTION__))
;
377 return BaseDefiningValueResult(I, false);
378}
379
380/// Helper function for findBasePointer - Will return a value which either a)
381/// defines the base pointer for the input, b) blocks the simple search
382/// (i.e. a PHI or Select of two derived pointers), or c) involves a change
383/// from pointer to vector type or back.
384static BaseDefiningValueResult findBaseDefiningValue(Value *I) {
385 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 386, __PRETTY_FUNCTION__))
386 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 386, __PRETTY_FUNCTION__))
;
387
388 if (I->getType()->isVectorTy())
389 return findBaseDefiningValueOfVector(I);
390
391 if (isa<Argument>(I))
392 // An incoming argument to the function is a base pointer
393 // We should have never reached here if this argument isn't an gc value
394 return BaseDefiningValueResult(I, true);
395
396 if (isa<Constant>(I)) {
397 // We assume that objects with a constant base (e.g. a global) can't move
398 // and don't need to be reported to the collector because they are always
399 // live. Besides global references, all kinds of constants (e.g. undef,
400 // constant expressions, null pointers) can be introduced by the inliner or
401 // the optimizer, especially on dynamically dead paths.
402 // Here we treat all of them as having single null base. By doing this we
403 // trying to avoid problems reporting various conflicts in a form of
404 // "phi (const1, const2)" or "phi (const, regular gc ptr)".
405 // See constant.ll file for relevant test cases.
406
407 return BaseDefiningValueResult(
408 ConstantPointerNull::get(cast<PointerType>(I->getType())), true);
409 }
410
411 if (CastInst *CI = dyn_cast<CastInst>(I)) {
412 Value *Def = CI->stripPointerCasts();
413 // If stripping pointer casts changes the address space there is an
414 // addrspacecast in between.
415 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 417, __PRETTY_FUNCTION__))
416 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 417, __PRETTY_FUNCTION__))
417 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 417, __PRETTY_FUNCTION__))
;
418 // If we find a cast instruction here, it means we've found a cast which is
419 // not simply a pointer cast (i.e. an inttoptr). We don't know how to
420 // handle int->ptr conversion.
421 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 421, __PRETTY_FUNCTION__))
;
422 return findBaseDefiningValue(Def);
423 }
424
425 if (isa<LoadInst>(I))
426 // The value loaded is an gc base itself
427 return BaseDefiningValueResult(I, true);
428
429
430 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
431 // The base of this GEP is the base
432 return findBaseDefiningValue(GEP->getPointerOperand());
433
434 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
435 switch (II->getIntrinsicID()) {
436 default:
437 // fall through to general call handling
438 break;
439 case Intrinsic::experimental_gc_statepoint:
440 llvm_unreachable("statepoints don't produce pointers")::llvm::llvm_unreachable_internal("statepoints don't produce pointers"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 440)
;
441 case Intrinsic::experimental_gc_relocate: {
442 // Rerunning safepoint insertion after safepoints are already
443 // inserted is not supported. It could probably be made to work,
444 // but why are you doing this? There's no good reason.
445 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 445)
;
446 }
447 case Intrinsic::gcroot:
448 // Currently, this mechanism hasn't been extended to work with gcroot.
449 // There's no reason it couldn't be, but I haven't thought about the
450 // implications much.
451 llvm_unreachable(::llvm::llvm_unreachable_internal("interaction with the gcroot mechanism is not supported"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 452)
452 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 452)
;
453 }
454 }
455 // We assume that functions in the source language only return base
456 // pointers. This should probably be generalized via attributes to support
457 // both source language and internal functions.
458 if (isa<CallInst>(I) || isa<InvokeInst>(I))
459 return BaseDefiningValueResult(I, true);
460
461 // TODO: I have absolutely no idea how to implement this part yet. It's not
462 // necessarily hard, I just haven't really looked at it yet.
463 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 463, __PRETTY_FUNCTION__))
;
464
465 if (isa<AtomicCmpXchgInst>(I))
466 // A CAS is effectively a atomic store and load combined under a
467 // predicate. From the perspective of base pointers, we just treat it
468 // like a load.
469 return BaseDefiningValueResult(I, true);
470
471 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 472, __PRETTY_FUNCTION__))
472 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 472, __PRETTY_FUNCTION__))
;
473
474 // The aggregate ops. Aggregates can either be in the heap or on the
475 // stack, but in either case, this is simply a field load. As a result,
476 // this is a defining definition of the base just like a load is.
477 if (isa<ExtractValueInst>(I))
478 return BaseDefiningValueResult(I, true);
479
480 // We should never see an insert vector since that would require we be
481 // tracing back a struct value not a pointer value.
482 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 483, __PRETTY_FUNCTION__))
483 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 483, __PRETTY_FUNCTION__))
;
484
485 // An extractelement produces a base result exactly when it's input does.
486 // We may need to insert a parallel instruction to extract the appropriate
487 // element out of the base vector corresponding to the input. Given this,
488 // it's analogous to the phi and select case even though it's not a merge.
489 if (isa<ExtractElementInst>(I))
490 // Note: There a lot of obvious peephole cases here. This are deliberately
491 // handled after the main base pointer inference algorithm to make writing
492 // test cases to exercise that code easier.
493 return BaseDefiningValueResult(I, false);
494
495 // The last two cases here don't return a base pointer. Instead, they
496 // return a value which dynamically selects from among several base
497 // derived pointers (each with it's own base potentially). It's the job of
498 // the caller to resolve these.
499 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 500, __PRETTY_FUNCTION__))
500 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 500, __PRETTY_FUNCTION__))
;
501 return BaseDefiningValueResult(I, false);
502}
503
504/// Returns the base defining value for this value.
505static Value *findBaseDefiningValueCached(Value *I, DefiningValueMapTy &Cache) {
506 Value *&Cached = Cache[I];
507 if (!Cached) {
508 Cached = findBaseDefiningValue(I).BDV;
509 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)
510 << Cached->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("rewrite-statepoints-for-gc")) { dbgs() << "fBDV-cached: "
<< I->getName() << " -> " << Cached->
getName() << "\n"; } } while (false)
;
511 }
512 assert(Cache[I] != nullptr)((Cache[I] != nullptr) ? static_cast<void> (0) : __assert_fail
("Cache[I] != nullptr", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 512, __PRETTY_FUNCTION__))
;
513 return Cached;
514}
515
516/// Return a base pointer for this value if known. Otherwise, return it's
517/// base defining value.
518static Value *findBaseOrBDV(Value *I, DefiningValueMapTy &Cache) {
519 Value *Def = findBaseDefiningValueCached(I, Cache);
520 auto Found = Cache.find(Def);
521 if (Found != Cache.end()) {
522 // Either a base-of relation, or a self reference. Caller must check.
523 return Found->second;
524 }
525 // Only a BDV available
526 return Def;
527}
528
529/// Given the result of a call to findBaseDefiningValue, or findBaseOrBDV,
530/// is it known to be a base pointer? Or do we need to continue searching.
531static bool isKnownBaseResult(Value *V) {
532 if (!isa<PHINode>(V) && !isa<SelectInst>(V) &&
533 !isa<ExtractElementInst>(V) && !isa<InsertElementInst>(V) &&
534 !isa<ShuffleVectorInst>(V)) {
535 // no recursion possible
536 return true;
537 }
538 if (isa<Instruction>(V) &&
539 cast<Instruction>(V)->getMetadata("is_base_value")) {
540 // This is a previously inserted base phi or select. We know
541 // that this is a base value.
542 return true;
543 }
544
545 // We need to keep searching
546 return false;
547}
548
549namespace {
550/// Models the state of a single base defining value in the findBasePointer
551/// algorithm for determining where a new instruction is needed to propagate
552/// the base of this BDV.
553class BDVState {
554public:
555 enum Status { Unknown, Base, Conflict };
556
557 BDVState() : Status(Unknown), BaseValue(nullptr) {}
558
559 explicit BDVState(Status Status, Value *BaseValue = nullptr)
560 : Status(Status), BaseValue(BaseValue) {
561 assert(Status != Base || BaseValue)((Status != Base || BaseValue) ? static_cast<void> (0) :
__assert_fail ("Status != Base || BaseValue", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 561, __PRETTY_FUNCTION__))
;
562 }
563
564 explicit BDVState(Value *BaseValue) : Status(Base), BaseValue(BaseValue) {}
565
566 Status getStatus() const { return Status; }
567 Value *getBaseValue() const { return BaseValue; }
568
569 bool isBase() const { return getStatus() == Base; }
570 bool isUnknown() const { return getStatus() == Unknown; }
571 bool isConflict() const { return getStatus() == Conflict; }
572
573 bool operator==(const BDVState &Other) const {
574 return BaseValue == Other.BaseValue && Status == Other.Status;
575 }
576
577 bool operator!=(const BDVState &other) const { return !(*this == other); }
578
579 LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__))
580 void dump() const {
581 print(dbgs());
582 dbgs() << '\n';
583 }
584
585 void print(raw_ostream &OS) const {
586 switch (getStatus()) {
587 case Unknown:
588 OS << "U";
589 break;
590 case Base:
591 OS << "B";
592 break;
593 case Conflict:
594 OS << "C";
595 break;
596 };
597 OS << " (" << getBaseValue() << " - "
598 << (getBaseValue() ? getBaseValue()->getName() : "nullptr") << "): ";
599 }
600
601private:
602 Status Status;
603 AssertingVH<Value> BaseValue; // Non-null only if Status == Base.
604};
605}
606
607#ifndef NDEBUG
608static raw_ostream &operator<<(raw_ostream &OS, const BDVState &State) {
609 State.print(OS);
610 return OS;
611}
612#endif
613
614static BDVState meetBDVStateImpl(const BDVState &LHS, const BDVState &RHS) {
615 switch (LHS.getStatus()) {
616 case BDVState::Unknown:
617 return RHS;
618
619 case BDVState::Base:
620 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 620, __PRETTY_FUNCTION__))
;
621 if (RHS.isUnknown())
622 return LHS;
623
624 if (RHS.isBase()) {
625 if (LHS.getBaseValue() == RHS.getBaseValue()) {
626 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 626, __PRETTY_FUNCTION__))
;
627 return LHS;
628 }
629 return BDVState(BDVState::Conflict);
630 }
631 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 631, __PRETTY_FUNCTION__))
;
632 return BDVState(BDVState::Conflict);
633
634 case BDVState::Conflict:
635 return LHS;
636 }
637 llvm_unreachable("only three states!")::llvm::llvm_unreachable_internal("only three states!", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 637)
;
638}
639
640// Values of type BDVState form a lattice, and this function implements the meet
641// operation.
642static BDVState meetBDVState(const BDVState &LHS, const BDVState &RHS) {
643 BDVState Result = meetBDVStateImpl(LHS, RHS);
644 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 645, __PRETTY_FUNCTION__))
645 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 645, __PRETTY_FUNCTION__))
;
646 return Result;
647}
648
649/// For a given value or instruction, figure out what base ptr its derived from.
650/// For gc objects, this is simply itself. On success, returns a value which is
651/// the base pointer. (This is reliable and can be used for relocation.) On
652/// failure, returns nullptr.
653static Value *findBasePointer(Value *I, DefiningValueMapTy &Cache) {
654 Value *Def = findBaseOrBDV(I, Cache);
655
656 if (isKnownBaseResult(Def))
657 return Def;
658
659 // Here's the rough algorithm:
660 // - For every SSA value, construct a mapping to either an actual base
661 // pointer or a PHI which obscures the base pointer.
662 // - Construct a mapping from PHI to unknown TOP state. Use an
663 // optimistic algorithm to propagate base pointer information. Lattice
664 // looks like:
665 // UNKNOWN
666 // b1 b2 b3 b4
667 // CONFLICT
668 // When algorithm terminates, all PHIs will either have a single concrete
669 // base or be in a conflict state.
670 // - For every conflict, insert a dummy PHI node without arguments. Add
671 // these to the base[Instruction] = BasePtr mapping. For every
672 // non-conflict, add the actual base.
673 // - For every conflict, add arguments for the base[a] of each input
674 // arguments.
675 //
676 // Note: A simpler form of this would be to add the conflict form of all
677 // PHIs without running the optimistic algorithm. This would be
678 // analogous to pessimistic data flow and would likely lead to an
679 // overall worse solution.
680
681#ifndef NDEBUG
682 auto isExpectedBDVType = [](Value *BDV) {
683 return isa<PHINode>(BDV) || isa<SelectInst>(BDV) ||
684 isa<ExtractElementInst>(BDV) || isa<InsertElementInst>(BDV) ||
685 isa<ShuffleVectorInst>(BDV);
686 };
687#endif
688
689 // Once populated, will contain a mapping from each potentially non-base BDV
690 // to a lattice value (described above) which corresponds to that BDV.
691 // We use the order of insertion (DFS over the def/use graph) to provide a
692 // stable deterministic ordering for visiting DenseMaps (which are unordered)
693 // below. This is important for deterministic compilation.
694 MapVector<Value *, BDVState> States;
695
696 // Recursively fill in all base defining values reachable from the initial
697 // one for which we don't already know a definite base value for
698 /* scope */ {
699 SmallVector<Value*, 16> Worklist;
700 Worklist.push_back(Def);
701 States.insert({Def, BDVState()});
702 while (!Worklist.empty()) {
703 Value *Current = Worklist.pop_back_val();
704 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 704, __PRETTY_FUNCTION__))
;
705
706 auto visitIncomingValue = [&](Value *InVal) {
707 Value *Base = findBaseOrBDV(InVal, Cache);
708 if (isKnownBaseResult(Base))
709 // Known bases won't need new instructions introduced and can be
710 // ignored safely
711 return;
712 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 713, __PRETTY_FUNCTION__))
713 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 713, __PRETTY_FUNCTION__))
;
714 if (States.insert(std::make_pair(Base, BDVState())).second)
715 Worklist.push_back(Base);
716 };
717 if (PHINode *PN = dyn_cast<PHINode>(Current)) {
718 for (Value *InVal : PN->incoming_values())
719 visitIncomingValue(InVal);
720 } else if (SelectInst *SI = dyn_cast<SelectInst>(Current)) {
721 visitIncomingValue(SI->getTrueValue());
722 visitIncomingValue(SI->getFalseValue());
723 } else if (auto *EE = dyn_cast<ExtractElementInst>(Current)) {
724 visitIncomingValue(EE->getVectorOperand());
725 } else if (auto *IE = dyn_cast<InsertElementInst>(Current)) {
726 visitIncomingValue(IE->getOperand(0)); // vector operand
727 visitIncomingValue(IE->getOperand(1)); // scalar operand
728 } else if (auto *SV = dyn_cast<ShuffleVectorInst>(Current)) {
729 visitIncomingValue(SV->getOperand(0));
730 visitIncomingValue(SV->getOperand(1));
731 }
732 else {
733 llvm_unreachable("Unimplemented instruction case")::llvm::llvm_unreachable_internal("Unimplemented instruction case"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 733)
;
734 }
735 }
736 }
737
738#ifndef NDEBUG
739 DEBUG(dbgs() << "States after initialization:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("rewrite-statepoints-for-gc")) { dbgs() << "States after initialization:\n"
; } } while (false)
;
740 for (auto Pair : States) {
741 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)
;
742 }
743#endif
744
745 // Return a phi state for a base defining value. We'll generate a new
746 // base state for known bases and expect to find a cached state otherwise.
747 auto getStateForBDV = [&](Value *baseValue) {
748 if (isKnownBaseResult(baseValue))
749 return BDVState(baseValue);
750 auto I = States.find(baseValue);
751 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 751, __PRETTY_FUNCTION__))
;
752 return I->second;
753 };
754
755 bool Progress = true;
756 while (Progress) {
757#ifndef NDEBUG
758 const size_t OldSize = States.size();
759#endif
760 Progress = false;
761 // We're only changing values in this loop, thus safe to keep iterators.
762 // Since this is computing a fixed point, the order of visit does not
763 // effect the result. TODO: We could use a worklist here and make this run
764 // much faster.
765 for (auto Pair : States) {
766 Value *BDV = Pair.first;
767 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 767, __PRETTY_FUNCTION__))
;
768
769 // Given an input value for the current instruction, return a BDVState
770 // instance which represents the BDV of that value.
771 auto getStateForInput = [&](Value *V) mutable {
772 Value *BDV = findBaseOrBDV(V, Cache);
773 return getStateForBDV(BDV);
774 };
775
776 BDVState NewState;
777 if (SelectInst *SI = dyn_cast<SelectInst>(BDV)) {
778 NewState = meetBDVState(NewState, getStateForInput(SI->getTrueValue()));
779 NewState =
780 meetBDVState(NewState, getStateForInput(SI->getFalseValue()));
781 } else if (PHINode *PN = dyn_cast<PHINode>(BDV)) {
782 for (Value *Val : PN->incoming_values())
783 NewState = meetBDVState(NewState, getStateForInput(Val));
784 } else if (auto *EE = dyn_cast<ExtractElementInst>(BDV)) {
785 // The 'meet' for an extractelement is slightly trivial, but it's still
786 // useful in that it drives us to conflict if our input is.
787 NewState =
788 meetBDVState(NewState, getStateForInput(EE->getVectorOperand()));
789 } else if (auto *IE = dyn_cast<InsertElementInst>(BDV)){
790 // Given there's a inherent type mismatch between the operands, will
791 // *always* produce Conflict.
792 NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(0)));
793 NewState = meetBDVState(NewState, getStateForInput(IE->getOperand(1)));
794 } else {
795 // The only instance this does not return a Conflict is when both the
796 // vector operands are the same vector.
797 auto *SV = cast<ShuffleVectorInst>(BDV);
798 NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(0)));
799 NewState = meetBDVState(NewState, getStateForInput(SV->getOperand(1)));
800 }
801
802 BDVState OldState = States[BDV];
803 if (OldState != NewState) {
804 Progress = true;
805 States[BDV] = NewState;
806 }
807 }
808
809 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 810, __PRETTY_FUNCTION__))
810 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 810, __PRETTY_FUNCTION__))
;
811 }
812
813#ifndef NDEBUG
814 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)
;
815 for (auto Pair : States) {
816 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)
;
817 }
818#endif
819
820 // Insert Phis for all conflicts
821 // TODO: adjust naming patterns to avoid this order of iteration dependency
822 for (auto Pair : States) {
823 Instruction *I = cast<Instruction>(Pair.first);
824 BDVState State = Pair.second;
825 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 825, __PRETTY_FUNCTION__))
;
826 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 826, __PRETTY_FUNCTION__))
;
827
828 // extractelement instructions are a bit special in that we may need to
829 // insert an extract even when we know an exact base for the instruction.
830 // The problem is that we need to convert from a vector base to a scalar
831 // base for the particular indice we're interested in.
832 if (State.isBase() && isa<ExtractElementInst>(I) &&
833 isa<VectorType>(State.getBaseValue()->getType())) {
834 auto *EE = cast<ExtractElementInst>(I);
835 // TODO: In many cases, the new instruction is just EE itself. We should
836 // exploit this, but can't do it here since it would break the invariant
837 // about the BDV not being known to be a base.
838 auto *BaseInst = ExtractElementInst::Create(
839 State.getBaseValue(), EE->getIndexOperand(), "base_ee", EE);
840 BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
841 States[I] = BDVState(BDVState::Base, BaseInst);
842 }
843
844 // Since we're joining a vector and scalar base, they can never be the
845 // same. As a result, we should always see insert element having reached
846 // the conflict state.
847 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 847, __PRETTY_FUNCTION__))
;
848
849 if (!State.isConflict())
850 continue;
851
852 /// Create and insert a new instruction which will represent the base of
853 /// the given instruction 'I'.
854 auto MakeBaseInstPlaceholder = [](Instruction *I) -> Instruction* {
855 if (isa<PHINode>(I)) {
856 BasicBlock *BB = I->getParent();
857 int NumPreds = std::distance(pred_begin(BB), pred_end(BB));
858 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 858, __PRETTY_FUNCTION__))
;
859 std::string Name = suffixed_name_or(I, ".base", "base_phi");
860 return PHINode::Create(I->getType(), NumPreds, Name, I);
861 } else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
862 // The undef will be replaced later
863 UndefValue *Undef = UndefValue::get(SI->getType());
864 std::string Name = suffixed_name_or(I, ".base", "base_select");
865 return SelectInst::Create(SI->getCondition(), Undef, Undef, Name, SI);
866 } else if (auto *EE = dyn_cast<ExtractElementInst>(I)) {
867 UndefValue *Undef = UndefValue::get(EE->getVectorOperand()->getType());
868 std::string Name = suffixed_name_or(I, ".base", "base_ee");
869 return ExtractElementInst::Create(Undef, EE->getIndexOperand(), Name,
870 EE);
871 } else if (auto *IE = dyn_cast<InsertElementInst>(I)) {
872 UndefValue *VecUndef = UndefValue::get(IE->getOperand(0)->getType());
873 UndefValue *ScalarUndef = UndefValue::get(IE->getOperand(1)->getType());
874 std::string Name = suffixed_name_or(I, ".base", "base_ie");
875 return InsertElementInst::Create(VecUndef, ScalarUndef,
876 IE->getOperand(2), Name, IE);
877 } else {
878 auto *SV = cast<ShuffleVectorInst>(I);
879 UndefValue *VecUndef = UndefValue::get(SV->getOperand(0)->getType());
880 std::string Name = suffixed_name_or(I, ".base", "base_sv");
881 return new ShuffleVectorInst(VecUndef, VecUndef, SV->getOperand(2),
882 Name, SV);
883 }
884 };
885 Instruction *BaseInst = MakeBaseInstPlaceholder(I);
886 // Add metadata marking this as a base value
887 BaseInst->setMetadata("is_base_value", MDNode::get(I->getContext(), {}));
888 States[I] = BDVState(BDVState::Conflict, BaseInst);
889 }
890
891 // Returns a instruction which produces the base pointer for a given
892 // instruction. The instruction is assumed to be an input to one of the BDVs
893 // seen in the inference algorithm above. As such, we must either already
894 // know it's base defining value is a base, or have inserted a new
895 // instruction to propagate the base of it's BDV and have entered that newly
896 // introduced instruction into the state table. In either case, we are
897 // assured to be able to determine an instruction which produces it's base
898 // pointer.
899 auto getBaseForInput = [&](Value *Input, Instruction *InsertPt) {
900 Value *BDV = findBaseOrBDV(Input, Cache);
901 Value *Base = nullptr;
902 if (isKnownBaseResult(BDV)) {
903 Base = BDV;
904 } else {
905 // Either conflict or base.
906 assert(States.count(BDV))((States.count(BDV)) ? static_cast<void> (0) : __assert_fail
("States.count(BDV)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 906, __PRETTY_FUNCTION__))
;
907 Base = States[BDV].getBaseValue();
908 }
909 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 909, __PRETTY_FUNCTION__))
;
910 // The cast is needed since base traversal may strip away bitcasts
911 if (Base->getType() != Input->getType() && InsertPt)
912 Base = new BitCastInst(Base, Input->getType(), "cast", InsertPt);
913 return Base;
914 };
915
916 // Fixup all the inputs of the new PHIs. Visit order needs to be
917 // deterministic and predictable because we're naming newly created
918 // instructions.
919 for (auto Pair : States) {
920 Instruction *BDV = cast<Instruction>(Pair.first);
921 BDVState State = Pair.second;
922
923 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 923, __PRETTY_FUNCTION__))
;
924 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 924, __PRETTY_FUNCTION__))
;
925 if (!State.isConflict())
926 continue;
927
928 if (PHINode *BasePHI = dyn_cast<PHINode>(State.getBaseValue())) {
929 PHINode *PN = cast<PHINode>(BDV);
930 unsigned NumPHIValues = PN->getNumIncomingValues();
931 for (unsigned i = 0; i < NumPHIValues; i++) {
932 Value *InVal = PN->getIncomingValue(i);
933 BasicBlock *InBB = PN->getIncomingBlock(i);
934
935 // If we've already seen InBB, add the same incoming value
936 // we added for it earlier. The IR verifier requires phi
937 // nodes with multiple entries from the same basic block
938 // to have the same incoming value for each of those
939 // entries. If we don't do this check here and basephi
940 // has a different type than base, we'll end up adding two
941 // bitcasts (and hence two distinct values) as incoming
942 // values for the same basic block.
943
944 int BlockIndex = BasePHI->getBasicBlockIndex(InBB);
945 if (BlockIndex != -1) {
946 Value *OldBase = BasePHI->getIncomingValue(BlockIndex);
947 BasePHI->addIncoming(OldBase, InBB);
948
949#ifndef NDEBUG
950 Value *Base = getBaseForInput(InVal, nullptr);
951 // In essence this assert states: the only way two values
952 // incoming from the same basic block may be different is by
953 // being different bitcasts of the same value. A cleanup
954 // that remains TODO is changing findBaseOrBDV to return an
955 // llvm::Value of the correct type (and still remain pure).
956 // This will remove the need to add bitcasts.
957 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 958, __PRETTY_FUNCTION__))
958 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 958, __PRETTY_FUNCTION__))
;
959#endif
960 continue;
961 }
962
963 // Find the instruction which produces the base for each input. We may
964 // need to insert a bitcast in the incoming block.
965 // TODO: Need to split critical edges if insertion is needed
966 Value *Base = getBaseForInput(InVal, InBB->getTerminator());
967 BasePHI->addIncoming(Base, InBB);
968 }
969 assert(BasePHI->getNumIncomingValues() == NumPHIValues)((BasePHI->getNumIncomingValues() == NumPHIValues) ? static_cast
<void> (0) : __assert_fail ("BasePHI->getNumIncomingValues() == NumPHIValues"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 969, __PRETTY_FUNCTION__))
;
970 } else if (SelectInst *BaseSI =
971 dyn_cast<SelectInst>(State.getBaseValue())) {
972 SelectInst *SI = cast<SelectInst>(BDV);
973
974 // Find the instruction which produces the base for each input.
975 // We may need to insert a bitcast.
976 BaseSI->setTrueValue(getBaseForInput(SI->getTrueValue(), BaseSI));
977 BaseSI->setFalseValue(getBaseForInput(SI->getFalseValue(), BaseSI));
978 } else if (auto *BaseEE =
979 dyn_cast<ExtractElementInst>(State.getBaseValue())) {
980 Value *InVal = cast<ExtractElementInst>(BDV)->getVectorOperand();
981 // Find the instruction which produces the base for each input. We may
982 // need to insert a bitcast.
983 BaseEE->setOperand(0, getBaseForInput(InVal, BaseEE));
984 } else if (auto *BaseIE = dyn_cast<InsertElementInst>(State.getBaseValue())){
985 auto *BdvIE = cast<InsertElementInst>(BDV);
986 auto UpdateOperand = [&](int OperandIdx) {
987 Value *InVal = BdvIE->getOperand(OperandIdx);
988 Value *Base = getBaseForInput(InVal, BaseIE);
989 BaseIE->setOperand(OperandIdx, Base);
Called C++ object pointer is null
990 };
991 UpdateOperand(0); // vector operand
992 UpdateOperand(1); // scalar operand
993 } else {
994 auto *BaseSV = cast<ShuffleVectorInst>(State.getBaseValue());
995 auto *BdvSV = cast<ShuffleVectorInst>(BDV);
996 auto UpdateOperand = [&](int OperandIdx) {
997 Value *InVal = BdvSV->getOperand(OperandIdx);
998 Value *Base = getBaseForInput(InVal, BaseSV);
999 BaseSV->setOperand(OperandIdx, Base);
1000 };
1001 UpdateOperand(0); // vector operand
1002 UpdateOperand(1); // vector operand
1003 }
1004 }
1005
1006 // Cache all of our results so we can cheaply reuse them
1007 // NOTE: This is actually two caches: one of the base defining value
1008 // relation and one of the base pointer relation! FIXME
1009 for (auto Pair : States) {
1010 auto *BDV = Pair.first;
1011 Value *Base = Pair.second.getBaseValue();
1012 assert(BDV && Base)((BDV && Base) ? static_cast<void> (0) : __assert_fail
("BDV && Base", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1012, __PRETTY_FUNCTION__))
;
1013 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1013, __PRETTY_FUNCTION__))
;
1014
1015 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)
1016 << " 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)
1017 << (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)
1018 << " 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)
;
1019
1020 if (Cache.count(BDV)) {
1021 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1022, __PRETTY_FUNCTION__))
1022 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1022, __PRETTY_FUNCTION__))
;
1023 // Once we transition from the BDV relation being store in the Cache to
1024 // the base relation being stored, it must be stable
1025 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1026, __PRETTY_FUNCTION__))
1026 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1026, __PRETTY_FUNCTION__))
;
1027 }
1028 Cache[BDV] = Base;
1029 }
1030 assert(Cache.count(Def))((Cache.count(Def)) ? static_cast<void> (0) : __assert_fail
("Cache.count(Def)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1030, __PRETTY_FUNCTION__))
;
1031 return Cache[Def];
1032}
1033
1034// For a set of live pointers (base and/or derived), identify the base
1035// pointer of the object which they are derived from. This routine will
1036// mutate the IR graph as needed to make the 'base' pointer live at the
1037// definition site of 'derived'. This ensures that any use of 'derived' can
1038// also use 'base'. This may involve the insertion of a number of
1039// additional PHI nodes.
1040//
1041// preconditions: live is a set of pointer type Values
1042//
1043// side effects: may insert PHI nodes into the existing CFG, will preserve
1044// CFG, will not remove or mutate any existing nodes
1045//
1046// post condition: PointerToBase contains one (derived, base) pair for every
1047// pointer in live. Note that derived can be equal to base if the original
1048// pointer was a base pointer.
1049static void
1050findBasePointers(const StatepointLiveSetTy &live,
1051 MapVector<Value *, Value *> &PointerToBase,
1052 DominatorTree *DT, DefiningValueMapTy &DVCache) {
1053 for (Value *ptr : live) {
1054 Value *base = findBasePointer(ptr, DVCache);
1055 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1055, __PRETTY_FUNCTION__))
;
1056 PointerToBase[ptr] = base;
1057 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1060, __PRETTY_FUNCTION__))
1058 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1060, __PRETTY_FUNCTION__))
1059 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1060, __PRETTY_FUNCTION__))
1060 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1060, __PRETTY_FUNCTION__))
;
1061 }
1062}
1063
1064/// Find the required based pointers (and adjust the live set) for the given
1065/// parse point.
1066static void findBasePointers(DominatorTree &DT, DefiningValueMapTy &DVCache,
1067 CallSite CS,
1068 PartiallyConstructedSafepointRecord &result) {
1069 MapVector<Value *, Value *> PointerToBase;
1070 findBasePointers(result.LiveSet, PointerToBase, &DT, DVCache);
1071
1072 if (PrintBasePointers) {
1073 errs() << "Base Pairs (w/o Relocation):\n";
1074 for (auto &Pair : PointerToBase) {
1075 errs() << " derived ";
1076 Pair.first->printAsOperand(errs(), false);
1077 errs() << " base ";
1078 Pair.second->printAsOperand(errs(), false);
1079 errs() << "\n";;
1080 }
1081 }
1082
1083 result.PointerToBase = PointerToBase;
1084}
1085
1086/// Given an updated version of the dataflow liveness results, update the
1087/// liveset and base pointer maps for the call site CS.
1088static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
1089 CallSite CS,
1090 PartiallyConstructedSafepointRecord &result);
1091
1092static void recomputeLiveInValues(
1093 Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
1094 MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
1095 // TODO-PERF: reuse the original liveness, then simply run the dataflow
1096 // again. The old values are still live and will help it stabilize quickly.
1097 GCPtrLivenessData RevisedLivenessData;
1098 computeLiveInValues(DT, F, RevisedLivenessData);
1099 for (size_t i = 0; i < records.size(); i++) {
1100 struct PartiallyConstructedSafepointRecord &info = records[i];
1101 recomputeLiveInValues(RevisedLivenessData, toUpdate[i], info);
1102 }
1103}
1104
1105// When inserting gc.relocate and gc.result calls, we need to ensure there are
1106// no uses of the original value / return value between the gc.statepoint and
1107// the gc.relocate / gc.result call. One case which can arise is a phi node
1108// starting one of the successor blocks. We also need to be able to insert the
1109// gc.relocates only on the path which goes through the statepoint. We might
1110// need to split an edge to make this possible.
1111static BasicBlock *
1112normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent,
1113 DominatorTree &DT) {
1114 BasicBlock *Ret = BB;
1115 if (!BB->getUniquePredecessor())
1116 Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
1117
1118 // Now that 'Ret' has unique predecessor we can safely remove all phi nodes
1119 // from it
1120 FoldSingleEntryPHINodes(Ret);
1121 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1122, __PRETTY_FUNCTION__))
1122 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1122, __PRETTY_FUNCTION__))
;
1123
1124 // At this point, we can safely insert a gc.relocate or gc.result as the first
1125 // instruction in Ret if needed.
1126 return Ret;
1127}
1128
1129// Create new attribute set containing only attributes which can be transferred
1130// from original call to the safepoint.
1131static AttributeSet legalizeCallAttributes(AttributeSet AS) {
1132 AttributeSet Ret;
1133
1134 for (unsigned Slot = 0; Slot < AS.getNumSlots(); Slot++) {
1135 unsigned Index = AS.getSlotIndex(Slot);
1136
1137 if (Index == AttributeSet::ReturnIndex ||
1138 Index == AttributeSet::FunctionIndex) {
1139
1140 for (Attribute Attr : make_range(AS.begin(Slot), AS.end(Slot))) {
1141
1142 // Do not allow certain attributes - just skip them
1143 // Safepoint can not be read only or read none.
1144 if (Attr.hasAttribute(Attribute::ReadNone) ||
1145 Attr.hasAttribute(Attribute::ReadOnly))
1146 continue;
1147
1148 // These attributes control the generation of the gc.statepoint call /
1149 // invoke itself; and once the gc.statepoint is in place, they're of no
1150 // use.
1151 if (isStatepointDirectiveAttr(Attr))
1152 continue;
1153
1154 Ret = Ret.addAttributes(
1155 AS.getContext(), Index,
1156 AttributeSet::get(AS.getContext(), Index, AttrBuilder(Attr)));
1157 }
1158 }
1159
1160 // Just skip parameter attributes for now
1161 }
1162
1163 return Ret;
1164}
1165
1166/// Helper function to place all gc relocates necessary for the given
1167/// statepoint.
1168/// Inputs:
1169/// liveVariables - list of variables to be relocated.
1170/// liveStart - index of the first live variable.
1171/// basePtrs - base pointers.
1172/// statepointToken - statepoint instruction to which relocates should be
1173/// bound.
1174/// Builder - Llvm IR builder to be used to construct new calls.
1175static void CreateGCRelocates(ArrayRef<Value *> LiveVariables,
1176 const int LiveStart,
1177 ArrayRef<Value *> BasePtrs,
1178 Instruction *StatepointToken,
1179 IRBuilder<> Builder) {
1180 if (LiveVariables.empty())
1181 return;
1182
1183 auto FindIndex = [](ArrayRef<Value *> LiveVec, Value *Val) {
1184 auto ValIt = find(LiveVec, Val);
1185 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1185, __PRETTY_FUNCTION__))
;
1186 size_t Index = std::distance(LiveVec.begin(), ValIt);
1187 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1187, __PRETTY_FUNCTION__))
;
1188 return Index;
1189 };
1190 Module *M = StatepointToken->getModule();
1191
1192 // All gc_relocate are generated as i8 addrspace(1)* (or a vector type whose
1193 // element type is i8 addrspace(1)*). We originally generated unique
1194 // declarations for each pointer type, but this proved problematic because
1195 // the intrinsic mangling code is incomplete and fragile. Since we're moving
1196 // towards a single unified pointer type anyways, we can just cast everything
1197 // to an i8* of the right address space. A bitcast is added later to convert
1198 // gc_relocate to the actual value's type.
1199 auto getGCRelocateDecl = [&] (Type *Ty) {
1200 assert(isHandledGCPointerType(Ty))((isHandledGCPointerType(Ty)) ? static_cast<void> (0) :
__assert_fail ("isHandledGCPointerType(Ty)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1200, __PRETTY_FUNCTION__))
;
1201 auto AS = Ty->getScalarType()->getPointerAddressSpace();
1202 Type *NewTy = Type::getInt8PtrTy(M->getContext(), AS);
1203 if (auto *VT = dyn_cast<VectorType>(Ty))
1204 NewTy = VectorType::get(NewTy, VT->getNumElements());
1205 return Intrinsic::getDeclaration(M, Intrinsic::experimental_gc_relocate,
1206 {NewTy});
1207 };
1208
1209 // Lazily populated map from input types to the canonicalized form mentioned
1210 // in the comment above. This should probably be cached somewhere more
1211 // broadly.
1212 DenseMap<Type*, Value*> TypeToDeclMap;
1213
1214 for (unsigned i = 0; i < LiveVariables.size(); i++) {
1215 // Generate the gc.relocate call and save the result
1216 Value *BaseIdx =
1217 Builder.getInt32(LiveStart + FindIndex(LiveVariables, BasePtrs[i]));
1218 Value *LiveIdx = Builder.getInt32(LiveStart + i);
1219
1220 Type *Ty = LiveVariables[i]->getType();
1221 if (!TypeToDeclMap.count(Ty))
1222 TypeToDeclMap[Ty] = getGCRelocateDecl(Ty);
1223 Value *GCRelocateDecl = TypeToDeclMap[Ty];
1224
1225 // only specify a debug name if we can give a useful one
1226 CallInst *Reloc = Builder.CreateCall(
1227 GCRelocateDecl, {StatepointToken, BaseIdx, LiveIdx},
1228 suffixed_name_or(LiveVariables[i], ".relocated", ""));
1229 // Trick CodeGen into thinking there are lots of free registers at this
1230 // fake call.
1231 Reloc->setCallingConv(CallingConv::Cold);
1232 }
1233}
1234
1235namespace {
1236
1237/// This struct is used to defer RAUWs and `eraseFromParent` s. Using this
1238/// avoids having to worry about keeping around dangling pointers to Values.
1239class DeferredReplacement {
1240 AssertingVH<Instruction> Old;
1241 AssertingVH<Instruction> New;
1242 bool IsDeoptimize = false;
1243
1244 DeferredReplacement() {}
1245
1246public:
1247 static DeferredReplacement createRAUW(Instruction *Old, Instruction *New) {
1248 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1249, __PRETTY_FUNCTION__))
1249 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1249, __PRETTY_FUNCTION__))
;
1250
1251 DeferredReplacement D;
1252 D.Old = Old;
1253 D.New = New;
1254 return D;
1255 }
1256
1257 static DeferredReplacement createDelete(Instruction *ToErase) {
1258 DeferredReplacement D;
1259 D.Old = ToErase;
1260 return D;
1261 }
1262
1263 static DeferredReplacement createDeoptimizeReplacement(Instruction *Old) {
1264#ifndef NDEBUG
1265 auto *F = cast<CallInst>(Old)->getCalledFunction();
1266 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1267, __PRETTY_FUNCTION__))
1267 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1267, __PRETTY_FUNCTION__))
;
1268#endif
1269 DeferredReplacement D;
1270 D.Old = Old;
1271 D.IsDeoptimize = true;
1272 return D;
1273 }
1274
1275 /// Does the task represented by this instance.
1276 void doReplacement() {
1277 Instruction *OldI = Old;
1278 Instruction *NewI = New;
1279
1280 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1280, __PRETTY_FUNCTION__))
;
1281 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1282, __PRETTY_FUNCTION__))
1282 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1282, __PRETTY_FUNCTION__))
;
1283
1284 Old = nullptr;
1285 New = nullptr;
1286
1287 if (NewI)
1288 OldI->replaceAllUsesWith(NewI);
1289
1290 if (IsDeoptimize) {
1291 // Note: we've inserted instructions, so the call to llvm.deoptimize may
1292 // not necessarilly be followed by the matching return.
1293 auto *RI = cast<ReturnInst>(OldI->getParent()->getTerminator());
1294 new UnreachableInst(RI->getContext(), RI);
1295 RI->eraseFromParent();
1296 }
1297
1298 OldI->eraseFromParent();
1299 }
1300};
1301}
1302
1303static StringRef getDeoptLowering(CallSite CS) {
1304 const char *DeoptLowering = "deopt-lowering";
1305 if (CS.hasFnAttr(DeoptLowering)) {
1306 // FIXME: CallSite has a *really* confusing interface around attributes
1307 // with values.
1308 const AttributeSet &CSAS = CS.getAttributes();
1309 if (CSAS.hasAttribute(AttributeSet::FunctionIndex,
1310 DeoptLowering))
1311 return CSAS.getAttribute(AttributeSet::FunctionIndex,
1312 DeoptLowering).getValueAsString();
1313 Function *F = CS.getCalledFunction();
1314 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1314, __PRETTY_FUNCTION__))
;
1315 return F->getFnAttribute(DeoptLowering).getValueAsString();
1316 }
1317 return "live-through";
1318}
1319
1320
1321static void
1322makeStatepointExplicitImpl(const CallSite CS, /* to replace */
1323 const SmallVectorImpl<Value *> &BasePtrs,
1324 const SmallVectorImpl<Value *> &LiveVariables,
1325 PartiallyConstructedSafepointRecord &Result,
1326 std::vector<DeferredReplacement> &Replacements) {
1327 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1327, __PRETTY_FUNCTION__))
;
1328
1329 // Then go ahead and use the builder do actually do the inserts. We insert
1330 // immediately before the previous instruction under the assumption that all
1331 // arguments will be available here. We can't insert afterwards since we may
1332 // be replacing a terminator.
1333 Instruction *InsertBefore = CS.getInstruction();
1334 IRBuilder<> Builder(InsertBefore);
1335
1336 ArrayRef<Value *> GCArgs(LiveVariables);
1337 uint64_t StatepointID = StatepointDirectives::DefaultStatepointID;
1338 uint32_t NumPatchBytes = 0;
1339 uint32_t Flags = uint32_t(StatepointFlags::None);
1340
1341 ArrayRef<Use> CallArgs(CS.arg_begin(), CS.arg_end());
1342 ArrayRef<Use> DeoptArgs = GetDeoptBundleOperands(CS);
1343 ArrayRef<Use> TransitionArgs;
1344 if (auto TransitionBundle =
1345 CS.getOperandBundle(LLVMContext::OB_gc_transition)) {
1346 Flags |= uint32_t(StatepointFlags::GCTransition);
1347 TransitionArgs = TransitionBundle->Inputs;
1348 }
1349
1350 // Instead of lowering calls to @llvm.experimental.deoptimize as normal calls
1351 // with a return value, we lower then as never returning calls to
1352 // __llvm_deoptimize that are followed by unreachable to get better codegen.
1353 bool IsDeoptimize = false;
1354
1355 StatepointDirectives SD =
1356 parseStatepointDirectivesFromAttrs(CS.getAttributes());
1357 if (SD.NumPatchBytes)
1358 NumPatchBytes = *SD.NumPatchBytes;
1359 if (SD.StatepointID)
1360 StatepointID = *SD.StatepointID;
1361
1362 // Pass through the requested lowering if any. The default is live-through.
1363 StringRef DeoptLowering = getDeoptLowering(CS);
1364 if (DeoptLowering.equals("live-in"))
1365 Flags |= uint32_t(StatepointFlags::DeoptLiveIn);
1366 else {
1367 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1367, __PRETTY_FUNCTION__))
;
1368 }
1369
1370 Value *CallTarget = CS.getCalledValue();
1371 if (Function *F = dyn_cast<Function>(CallTarget)) {
1372 if (F->getIntrinsicID() == Intrinsic::experimental_deoptimize) {
1373 // Calls to llvm.experimental.deoptimize are lowered to calls to the
1374 // __llvm_deoptimize symbol. We want to resolve this now, since the
1375 // verifier does not allow taking the address of an intrinsic function.
1376
1377 SmallVector<Type *, 8> DomainTy;
1378 for (Value *Arg : CallArgs)
1379 DomainTy.push_back(Arg->getType());
1380 auto *FTy = FunctionType::get(Type::getVoidTy(F->getContext()), DomainTy,
1381 /* isVarArg = */ false);
1382
1383 // Note: CallTarget can be a bitcast instruction of a symbol if there are
1384 // calls to @llvm.experimental.deoptimize with different argument types in
1385 // the same module. This is fine -- we assume the frontend knew what it
1386 // was doing when generating this kind of IR.
1387 CallTarget =
1388 F->getParent()->getOrInsertFunction("__llvm_deoptimize", FTy);
1389
1390 IsDeoptimize = true;
1391 }
1392 }
1393
1394 // Create the statepoint given all the arguments
1395 Instruction *Token = nullptr;
1396 AttributeSet ReturnAttrs;
1397 if (CS.isCall()) {
1398 CallInst *ToReplace = cast<CallInst>(CS.getInstruction());
1399 CallInst *Call = Builder.CreateGCStatepointCall(
1400 StatepointID, NumPatchBytes, CallTarget, Flags, CallArgs,
1401 TransitionArgs, DeoptArgs, GCArgs, "safepoint_token");
1402
1403 Call->setTailCallKind(ToReplace->getTailCallKind());
1404 Call->setCallingConv(ToReplace->getCallingConv());
1405
1406 // Currently we will fail on parameter attributes and on certain
1407 // function attributes.
1408 AttributeSet NewAttrs = legalizeCallAttributes(ToReplace->getAttributes());
1409 // In case if we can handle this set of attributes - set up function attrs
1410 // directly on statepoint and return attrs later for gc_result intrinsic.
1411 Call->setAttributes(NewAttrs.getFnAttributes());
1412 ReturnAttrs = NewAttrs.getRetAttributes();
1413
1414 Token = Call;
1415
1416 // Put the following gc_result and gc_relocate calls immediately after the
1417 // the old call (which we're about to delete)
1418 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1418, __PRETTY_FUNCTION__))
;
1419 Builder.SetInsertPoint(ToReplace->getNextNode());
1420 Builder.SetCurrentDebugLocation(ToReplace->getNextNode()->getDebugLoc());
1421 } else {
1422 InvokeInst *ToReplace = cast<InvokeInst>(CS.getInstruction());
1423
1424 // Insert the new invoke into the old block. We'll remove the old one in a
1425 // moment at which point this will become the new terminator for the
1426 // original block.
1427 InvokeInst *Invoke = Builder.CreateGCStatepointInvoke(
1428 StatepointID, NumPatchBytes, CallTarget, ToReplace->getNormalDest(),
1429 ToReplace->getUnwindDest(), Flags, CallArgs, TransitionArgs, DeoptArgs,
1430 GCArgs, "statepoint_token");
1431
1432 Invoke->setCallingConv(ToReplace->getCallingConv());
1433
1434 // Currently we will fail on parameter attributes and on certain
1435 // function attributes.
1436 AttributeSet NewAttrs = legalizeCallAttributes(ToReplace->getAttributes());
1437 // In case if we can handle this set of attributes - set up function attrs
1438 // directly on statepoint and return attrs later for gc_result intrinsic.
1439 Invoke->setAttributes(NewAttrs.getFnAttributes());
1440 ReturnAttrs = NewAttrs.getRetAttributes();
1441
1442 Token = Invoke;
1443
1444 // Generate gc relocates in exceptional path
1445 BasicBlock *UnwindBlock = ToReplace->getUnwindDest();
1446 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1448, __PRETTY_FUNCTION__))
1447 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1448, __PRETTY_FUNCTION__))
1448 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1448, __PRETTY_FUNCTION__))
;
1449
1450 Builder.SetInsertPoint(&*UnwindBlock->getFirstInsertionPt());
1451 Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
1452
1453 // Attach exceptional gc relocates to the landingpad.
1454 Instruction *ExceptionalToken = UnwindBlock->getLandingPadInst();
1455 Result.UnwindToken = ExceptionalToken;
1456
1457 const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1458 CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, ExceptionalToken,
1459 Builder);
1460
1461 // Generate gc relocates and returns for normal block
1462 BasicBlock *NormalDest = ToReplace->getNormalDest();
1463 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1465, __PRETTY_FUNCTION__))
1464 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1465, __PRETTY_FUNCTION__))
1465 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1465, __PRETTY_FUNCTION__))
;
1466
1467 Builder.SetInsertPoint(&*NormalDest->getFirstInsertionPt());
1468
1469 // gc relocates will be generated later as if it were regular call
1470 // statepoint
1471 }
1472 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1472, __PRETTY_FUNCTION__))
;
1473
1474 if (IsDeoptimize) {
1475 // If we're wrapping an @llvm.experimental.deoptimize in a statepoint, we
1476 // transform the tail-call like structure to a call to a void function
1477 // followed by unreachable to get better codegen.
1478 Replacements.push_back(
1479 DeferredReplacement::createDeoptimizeReplacement(CS.getInstruction()));
1480 } else {
1481 Token->setName("statepoint_token");
1482 if (!CS.getType()->isVoidTy() && !CS.getInstruction()->use_empty()) {
1483 StringRef Name =
1484 CS.getInstruction()->hasName() ? CS.getInstruction()->getName() : "";
1485 CallInst *GCResult = Builder.CreateGCResult(Token, CS.getType(), Name);
1486 GCResult->setAttributes(CS.getAttributes().getRetAttributes());
1487
1488 // We cannot RAUW or delete CS.getInstruction() because it could be in the
1489 // live set of some other safepoint, in which case that safepoint's
1490 // PartiallyConstructedSafepointRecord will hold a raw pointer to this
1491 // llvm::Instruction. Instead, we defer the replacement and deletion to
1492 // after the live sets have been made explicit in the IR, and we no longer
1493 // have raw pointers to worry about.
1494 Replacements.emplace_back(
1495 DeferredReplacement::createRAUW(CS.getInstruction(), GCResult));
1496 } else {
1497 Replacements.emplace_back(
1498 DeferredReplacement::createDelete(CS.getInstruction()));
1499 }
1500 }
1501
1502 Result.StatepointToken = Token;
1503
1504 // Second, create a gc.relocate for every live variable
1505 const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
1506 CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, Token, Builder);
1507}
1508
1509// Replace an existing gc.statepoint with a new one and a set of gc.relocates
1510// which make the relocations happening at this safepoint explicit.
1511//
1512// WARNING: Does not do any fixup to adjust users of the original live
1513// values. That's the callers responsibility.
1514static void
1515makeStatepointExplicit(DominatorTree &DT, CallSite CS,
1516 PartiallyConstructedSafepointRecord &Result,
1517 std::vector<DeferredReplacement> &Replacements) {
1518 const auto &LiveSet = Result.LiveSet;
1519 const auto &PointerToBase = Result.PointerToBase;
1520
1521 // Convert to vector for efficient cross referencing.
1522 SmallVector<Value *, 64> BaseVec, LiveVec;
1523 LiveVec.reserve(LiveSet.size());
1524 BaseVec.reserve(LiveSet.size());
1525 for (Value *L : LiveSet) {
1526 LiveVec.push_back(L);
1527 assert(PointerToBase.count(L))((PointerToBase.count(L)) ? static_cast<void> (0) : __assert_fail
("PointerToBase.count(L)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1527, __PRETTY_FUNCTION__))
;
1528 Value *Base = PointerToBase.find(L)->second;
1529 BaseVec.push_back(Base);
1530 }
1531 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1531, __PRETTY_FUNCTION__))
;
1532
1533 // Do the actual rewriting and delete the old statepoint
1534 makeStatepointExplicitImpl(CS, BaseVec, LiveVec, Result, Replacements);
1535}
1536
1537// Helper function for the relocationViaAlloca.
1538//
1539// It receives iterator to the statepoint gc relocates and emits a store to the
1540// assigned location (via allocaMap) for the each one of them. It adds the
1541// visited values into the visitedLiveValues set, which we will later use them
1542// for sanity checking.
1543static void
1544insertRelocationStores(iterator_range<Value::user_iterator> GCRelocs,
1545 DenseMap<Value *, Value *> &AllocaMap,
1546 DenseSet<Value *> &VisitedLiveValues) {
1547
1548 for (User *U : GCRelocs) {
1549 GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U);
1550 if (!Relocate)
1551 continue;
1552
1553 Value *OriginalValue = Relocate->getDerivedPtr();
1554 assert(AllocaMap.count(OriginalValue))((AllocaMap.count(OriginalValue)) ? static_cast<void> (
0) : __assert_fail ("AllocaMap.count(OriginalValue)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1554, __PRETTY_FUNCTION__))
;
1555 Value *Alloca = AllocaMap[OriginalValue];
1556
1557 // Emit store into the related alloca
1558 // All gc_relocates are i8 addrspace(1)* typed, and it must be bitcasted to
1559 // the correct type according to alloca.
1560 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1561, __PRETTY_FUNCTION__))
1561 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1561, __PRETTY_FUNCTION__))
;
1562 IRBuilder<> Builder(Relocate->getNextNode());
1563 Value *CastedRelocatedValue =
1564 Builder.CreateBitCast(Relocate,
1565 cast<AllocaInst>(Alloca)->getAllocatedType(),
1566 suffixed_name_or(Relocate, ".casted", ""));
1567
1568 StoreInst *Store = new StoreInst(CastedRelocatedValue, Alloca);
1569 Store->insertAfter(cast<Instruction>(CastedRelocatedValue));
1570
1571#ifndef NDEBUG
1572 VisitedLiveValues.insert(OriginalValue);
1573#endif
1574 }
1575}
1576
1577// Helper function for the "relocationViaAlloca". Similar to the
1578// "insertRelocationStores" but works for rematerialized values.
1579static void insertRematerializationStores(
1580 const RematerializedValueMapTy &RematerializedValues,
1581 DenseMap<Value *, Value *> &AllocaMap,
1582 DenseSet<Value *> &VisitedLiveValues) {
1583
1584 for (auto RematerializedValuePair: RematerializedValues) {
1585 Instruction *RematerializedValue = RematerializedValuePair.first;
1586 Value *OriginalValue = RematerializedValuePair.second;
1587
1588 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1589, __PRETTY_FUNCTION__))
1589 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1589, __PRETTY_FUNCTION__))
;
1590 Value *Alloca = AllocaMap[OriginalValue];
1591
1592 StoreInst *Store = new StoreInst(RematerializedValue, Alloca);
1593 Store->insertAfter(RematerializedValue);
1594
1595#ifndef NDEBUG
1596 VisitedLiveValues.insert(OriginalValue);
1597#endif
1598 }
1599}
1600
1601/// Do all the relocation update via allocas and mem2reg
1602static void relocationViaAlloca(
1603 Function &F, DominatorTree &DT, ArrayRef<Value *> Live,
1604 ArrayRef<PartiallyConstructedSafepointRecord> Records) {
1605#ifndef NDEBUG
1606 // record initial number of (static) allocas; we'll check we have the same
1607 // number when we get done.
1608 int InitialAllocaNum = 0;
1609 for (Instruction &I : F.getEntryBlock())
1610 if (isa<AllocaInst>(I))
1611 InitialAllocaNum++;
1612#endif
1613
1614 // TODO-PERF: change data structures, reserve
1615 DenseMap<Value *, Value *> AllocaMap;
1616 SmallVector<AllocaInst *, 200> PromotableAllocas;
1617 // Used later to chack that we have enough allocas to store all values
1618 std::size_t NumRematerializedValues = 0;
1619 PromotableAllocas.reserve(Live.size());
1620
1621 // Emit alloca for "LiveValue" and record it in "allocaMap" and
1622 // "PromotableAllocas"
1623 auto emitAllocaFor = [&](Value *LiveValue) {
1624 AllocaInst *Alloca = new AllocaInst(LiveValue->getType(), "",
1625 F.getEntryBlock().getFirstNonPHI());
1626 AllocaMap[LiveValue] = Alloca;
1627 PromotableAllocas.push_back(Alloca);
1628 };
1629
1630 // Emit alloca for each live gc pointer
1631 for (Value *V : Live)
1632 emitAllocaFor(V);
1633
1634 // Emit allocas for rematerialized values
1635 for (const auto &Info : Records)
1636 for (auto RematerializedValuePair : Info.RematerializedValues) {
1637 Value *OriginalValue = RematerializedValuePair.second;
1638 if (AllocaMap.count(OriginalValue) != 0)
1639 continue;
1640
1641 emitAllocaFor(OriginalValue);
1642 ++NumRematerializedValues;
1643 }
1644
1645 // The next two loops are part of the same conceptual operation. We need to
1646 // insert a store to the alloca after the original def and at each
1647 // redefinition. We need to insert a load before each use. These are split
1648 // into distinct loops for performance reasons.
1649
1650 // Update gc pointer after each statepoint: either store a relocated value or
1651 // null (if no relocated value was found for this gc pointer and it is not a
1652 // gc_result). This must happen before we update the statepoint with load of
1653 // alloca otherwise we lose the link between statepoint and old def.
1654 for (const auto &Info : Records) {
1655 Value *Statepoint = Info.StatepointToken;
1656
1657 // This will be used for consistency check
1658 DenseSet<Value *> VisitedLiveValues;
1659
1660 // Insert stores for normal statepoint gc relocates
1661 insertRelocationStores(Statepoint->users(), AllocaMap, VisitedLiveValues);
1662
1663 // In case if it was invoke statepoint
1664 // we will insert stores for exceptional path gc relocates.
1665 if (isa<InvokeInst>(Statepoint)) {
1666 insertRelocationStores(Info.UnwindToken->users(), AllocaMap,
1667 VisitedLiveValues);
1668 }
1669
1670 // Do similar thing with rematerialized values
1671 insertRematerializationStores(Info.RematerializedValues, AllocaMap,
1672 VisitedLiveValues);
1673
1674 if (ClobberNonLive) {
1675 // As a debugging aid, pretend that an unrelocated pointer becomes null at
1676 // the gc.statepoint. This will turn some subtle GC problems into
1677 // slightly easier to debug SEGVs. Note that on large IR files with
1678 // lots of gc.statepoints this is extremely costly both memory and time
1679 // wise.
1680 SmallVector<AllocaInst *, 64> ToClobber;
1681 for (auto Pair : AllocaMap) {
1682 Value *Def = Pair.first;
1683 AllocaInst *Alloca = cast<AllocaInst>(Pair.second);
1684
1685 // This value was relocated
1686 if (VisitedLiveValues.count(Def)) {
1687 continue;
1688 }
1689 ToClobber.push_back(Alloca);
1690 }
1691
1692 auto InsertClobbersAt = [&](Instruction *IP) {
1693 for (auto *AI : ToClobber) {
1694 auto PT = cast<PointerType>(AI->getAllocatedType());
1695 Constant *CPN = ConstantPointerNull::get(PT);
1696 StoreInst *Store = new StoreInst(CPN, AI);
1697 Store->insertBefore(IP);
1698 }
1699 };
1700
1701 // Insert the clobbering stores. These may get intermixed with the
1702 // gc.results and gc.relocates, but that's fine.
1703 if (auto II = dyn_cast<InvokeInst>(Statepoint)) {
1704 InsertClobbersAt(&*II->getNormalDest()->getFirstInsertionPt());
1705 InsertClobbersAt(&*II->getUnwindDest()->getFirstInsertionPt());
1706 } else {
1707 InsertClobbersAt(cast<Instruction>(Statepoint)->getNextNode());
1708 }
1709 }
1710 }
1711
1712 // Update use with load allocas and add store for gc_relocated.
1713 for (auto Pair : AllocaMap) {
1714 Value *Def = Pair.first;
1715 Value *Alloca = Pair.second;
1716
1717 // We pre-record the uses of allocas so that we dont have to worry about
1718 // later update that changes the user information..
1719
1720 SmallVector<Instruction *, 20> Uses;
1721 // PERF: trade a linear scan for repeated reallocation
1722 Uses.reserve(std::distance(Def->user_begin(), Def->user_end()));
1723 for (User *U : Def->users()) {
1724 if (!isa<ConstantExpr>(U)) {
1725 // If the def has a ConstantExpr use, then the def is either a
1726 // ConstantExpr use itself or null. In either case
1727 // (recursively in the first, directly in the second), the oop
1728 // it is ultimately dependent on is null and this particular
1729 // use does not need to be fixed up.
1730 Uses.push_back(cast<Instruction>(U));
1731 }
1732 }
1733
1734 std::sort(Uses.begin(), Uses.end());
1735 auto Last = std::unique(Uses.begin(), Uses.end());
1736 Uses.erase(Last, Uses.end());
1737
1738 for (Instruction *Use : Uses) {
1739 if (isa<PHINode>(Use)) {
1740 PHINode *Phi = cast<PHINode>(Use);
1741 for (unsigned i = 0; i < Phi->getNumIncomingValues(); i++) {
1742 if (Def == Phi->getIncomingValue(i)) {
1743 LoadInst *Load = new LoadInst(
1744 Alloca, "", Phi->getIncomingBlock(i)->getTerminator());
1745 Phi->setIncomingValue(i, Load);
1746 }
1747 }
1748 } else {
1749 LoadInst *Load = new LoadInst(Alloca, "", Use);
1750 Use->replaceUsesOfWith(Def, Load);
1751 }
1752 }
1753
1754 // Emit store for the initial gc value. Store must be inserted after load,
1755 // otherwise store will be in alloca's use list and an extra load will be
1756 // inserted before it.
1757 StoreInst *Store = new StoreInst(Def, Alloca);
1758 if (Instruction *Inst = dyn_cast<Instruction>(Def)) {
1759 if (InvokeInst *Invoke = dyn_cast<InvokeInst>(Inst)) {
1760 // InvokeInst is a TerminatorInst so the store need to be inserted
1761 // into its normal destination block.
1762 BasicBlock *NormalDest = Invoke->getNormalDest();
1763 Store->insertBefore(NormalDest->getFirstNonPHI());
1764 } else {
1765 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1767, __PRETTY_FUNCTION__))
1766 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1767, __PRETTY_FUNCTION__))
1767 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1767, __PRETTY_FUNCTION__))
;
1768 Store->insertAfter(Inst);
1769 }
1770 } else {
1771 assert(isa<Argument>(Def))((isa<Argument>(Def)) ? static_cast<void> (0) : __assert_fail
("isa<Argument>(Def)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1771, __PRETTY_FUNCTION__))
;
1772 Store->insertAfter(cast<Instruction>(Alloca));
1773 }
1774 }
1775
1776 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1777, __PRETTY_FUNCTION__))
1777 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1777, __PRETTY_FUNCTION__))
;
1778 if (!PromotableAllocas.empty()) {
1779 // Apply mem2reg to promote alloca to SSA
1780 PromoteMemToReg(PromotableAllocas, DT);
1781 }
1782
1783#ifndef NDEBUG
1784 for (auto &I : F.getEntryBlock())
1785 if (isa<AllocaInst>(I))
1786 InitialAllocaNum--;
1787 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1787, __PRETTY_FUNCTION__))
;
1788#endif
1789}
1790
1791/// Implement a unique function which doesn't require we sort the input
1792/// vector. Doing so has the effect of changing the output of a couple of
1793/// tests in ways which make them less useful in testing fused safepoints.
1794template <typename T> static void unique_unsorted(SmallVectorImpl<T> &Vec) {
1795 SmallSet<T, 8> Seen;
1796 Vec.erase(remove_if(Vec, [&](const T &V) { return !Seen.insert(V).second; }),
1797 Vec.end());
1798}
1799
1800/// Insert holders so that each Value is obviously live through the entire
1801/// lifetime of the call.
1802static void insertUseHolderAfter(CallSite &CS, const ArrayRef<Value *> Values,
1803 SmallVectorImpl<CallInst *> &Holders) {
1804 if (Values.empty())
1805 // No values to hold live, might as well not insert the empty holder
1806 return;
1807
1808 Module *M = CS.getInstruction()->getModule();
1809 // Use a dummy vararg function to actually hold the values live
1810 Function *Func = cast<Function>(M->getOrInsertFunction(
1811 "__tmp_use", FunctionType::get(Type::getVoidTy(M->getContext()), true)));
1812 if (CS.isCall()) {
1813 // For call safepoints insert dummy calls right after safepoint
1814 Holders.push_back(CallInst::Create(Func, Values, "",
1815 &*++CS.getInstruction()->getIterator()));
1816 return;
1817 }
1818 // For invoke safepooints insert dummy calls both in normal and
1819 // exceptional destination blocks
1820 auto *II = cast<InvokeInst>(CS.getInstruction());
1821 Holders.push_back(CallInst::Create(
1822 Func, Values, "", &*II->getNormalDest()->getFirstInsertionPt()));
1823 Holders.push_back(CallInst::Create(
1824 Func, Values, "", &*II->getUnwindDest()->getFirstInsertionPt()));
1825}
1826
1827static void findLiveReferences(
1828 Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
1829 MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
1830 GCPtrLivenessData OriginalLivenessData;
1831 computeLiveInValues(DT, F, OriginalLivenessData);
1832 for (size_t i = 0; i < records.size(); i++) {
1833 struct PartiallyConstructedSafepointRecord &info = records[i];
1834 analyzeParsePointLiveness(DT, OriginalLivenessData, toUpdate[i], info);
1835 }
1836}
1837
1838// Helper function for the "rematerializeLiveValues". It walks use chain
1839// starting from the "CurrentValue" until it reaches the root of the chain, i.e.
1840// the base or a value it cannot process. Only "simple" values are processed
1841// (currently it is GEP's and casts). The returned root is examined by the
1842// callers of findRematerializableChainToBasePointer. Fills "ChainToBase" array
1843// with all visited values.
1844static Value* findRematerializableChainToBasePointer(
1845 SmallVectorImpl<Instruction*> &ChainToBase,
1846 Value *CurrentValue) {
1847
1848 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(CurrentValue)) {
1849 ChainToBase.push_back(GEP);
1850 return findRematerializableChainToBasePointer(ChainToBase,
1851 GEP->getPointerOperand());
1852 }
1853
1854 if (CastInst *CI = dyn_cast<CastInst>(CurrentValue)) {
1855 if (!CI->isNoopCast(CI->getModule()->getDataLayout()))
1856 return CI;
1857
1858 ChainToBase.push_back(CI);
1859 return findRematerializableChainToBasePointer(ChainToBase,
1860 CI->getOperand(0));
1861 }
1862
1863 // We have reached the root of the chain, which is either equal to the base or
1864 // is the first unsupported value along the use chain.
1865 return CurrentValue;
1866}
1867
1868// Helper function for the "rematerializeLiveValues". Compute cost of the use
1869// chain we are going to rematerialize.
1870static unsigned
1871chainToBasePointerCost(SmallVectorImpl<Instruction*> &Chain,
1872 TargetTransformInfo &TTI) {
1873 unsigned Cost = 0;
1874
1875 for (Instruction *Instr : Chain) {
1876 if (CastInst *CI = dyn_cast<CastInst>(Instr)) {
1877 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1878, __PRETTY_FUNCTION__))
1878 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1878, __PRETTY_FUNCTION__))
;
1879
1880 Type *SrcTy = CI->getOperand(0)->getType();
1881 Cost += TTI.getCastInstrCost(CI->getOpcode(), CI->getType(), SrcTy);
1882
1883 } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Instr)) {
1884 // Cost of the address calculation
1885 Type *ValTy = GEP->getSourceElementType();
1886 Cost += TTI.getAddressComputationCost(ValTy);
1887
1888 // And cost of the GEP itself
1889 // TODO: Use TTI->getGEPCost here (it exists, but appears to be not
1890 // allowed for the external usage)
1891 if (!GEP->hasAllConstantIndices())
1892 Cost += 2;
1893
1894 } else {
1895 llvm_unreachable("unsupported instruciton type during rematerialization")::llvm::llvm_unreachable_internal("unsupported instruciton type during rematerialization"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1895)
;
1896 }
1897 }
1898
1899 return Cost;
1900}
1901
1902static bool AreEquivalentPhiNodes(PHINode &OrigRootPhi, PHINode &AlternateRootPhi) {
1903
1904 unsigned PhiNum = OrigRootPhi.getNumIncomingValues();
1905 if (PhiNum != AlternateRootPhi.getNumIncomingValues() ||
1906 OrigRootPhi.getParent() != AlternateRootPhi.getParent())
1907 return false;
1908 // Map of incoming values and their corresponding basic blocks of
1909 // OrigRootPhi.
1910 SmallDenseMap<Value *, BasicBlock *, 8> CurrentIncomingValues;
1911 for (unsigned i = 0; i < PhiNum; i++)
1912 CurrentIncomingValues[OrigRootPhi.getIncomingValue(i)] =
1913 OrigRootPhi.getIncomingBlock(i);
1914
1915 // Both current and base PHIs should have same incoming values and
1916 // the same basic blocks corresponding to the incoming values.
1917 for (unsigned i = 0; i < PhiNum; i++) {
1918 auto CIVI =
1919 CurrentIncomingValues.find(AlternateRootPhi.getIncomingValue(i));
1920 if (CIVI == CurrentIncomingValues.end())
1921 return false;
1922 BasicBlock *CurrentIncomingBB = CIVI->second;
1923 if (CurrentIncomingBB != AlternateRootPhi.getIncomingBlock(i))
1924 return false;
1925 }
1926 return true;
1927
1928}
1929
1930// From the statepoint live set pick values that are cheaper to recompute then
1931// to relocate. Remove this values from the live set, rematerialize them after
1932// statepoint and record them in "Info" structure. Note that similar to
1933// relocated values we don't do any user adjustments here.
1934static void rematerializeLiveValues(CallSite CS,
1935 PartiallyConstructedSafepointRecord &Info,
1936 TargetTransformInfo &TTI) {
1937 const unsigned int ChainLengthThreshold = 10;
1938
1939 // Record values we are going to delete from this statepoint live set.
1940 // We can not di this in following loop due to iterator invalidation.
1941 SmallVector<Value *, 32> LiveValuesToBeDeleted;
1942
1943 for (Value *LiveValue: Info.LiveSet) {
1944 // For each live pointer find it's defining chain
1945 SmallVector<Instruction *, 3> ChainToBase;
1946 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1946, __PRETTY_FUNCTION__))
;
1947 Value *RootOfChain =
1948 findRematerializableChainToBasePointer(ChainToBase,
1949 LiveValue);
1950
1951 // Nothing to do, or chain is too long
1952 if ( ChainToBase.size() == 0 ||
1953 ChainToBase.size() > ChainLengthThreshold)
1954 continue;
1955
1956 // Handle the scenario where the RootOfChain is not equal to the
1957 // Base Value, but they are essentially the same phi values.
1958 if (RootOfChain != Info.PointerToBase[LiveValue]) {
1959 PHINode *OrigRootPhi = dyn_cast<PHINode>(RootOfChain);
1960 PHINode *AlternateRootPhi = dyn_cast<PHINode>(Info.PointerToBase[LiveValue]);
1961 if (!OrigRootPhi || !AlternateRootPhi)
1962 continue;
1963 // PHI nodes that have the same incoming values, and belonging to the same
1964 // basic blocks are essentially the same SSA value. When the original phi
1965 // has incoming values with different base pointers, the original phi is
1966 // marked as conflict, and an additional `AlternateRootPhi` with the same
1967 // incoming values get generated by the findBasePointer function. We need
1968 // to identify the newly generated AlternateRootPhi (.base version of phi)
1969 // and RootOfChain (the original phi node itself) are the same, so that we
1970 // can rematerialize the gep and casts. This is a workaround for the
1971 // deficieny in the findBasePointer algorithm.
1972 if (!AreEquivalentPhiNodes(*OrigRootPhi, *AlternateRootPhi))
1973 continue;
1974 // Now that the phi nodes are proved to be the same, assert that
1975 // findBasePointer's newly generated AlternateRootPhi is present in the
1976 // liveset of the call.
1977 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 1977, __PRETTY_FUNCTION__))
;
1978 }
1979 // Compute cost of this chain
1980 unsigned Cost = chainToBasePointerCost(ChainToBase, TTI);
1981 // TODO: We can also account for cases when we will be able to remove some
1982 // of the rematerialized values by later optimization passes. I.e if
1983 // we rematerialized several intersecting chains. Or if original values
1984 // don't have any uses besides this statepoint.
1985
1986 // For invokes we need to rematerialize each chain twice - for normal and
1987 // for unwind basic blocks. Model this by multiplying cost by two.
1988 if (CS.isInvoke()) {
1989 Cost *= 2;
1990 }
1991 // If it's too expensive - skip it
1992 if (Cost >= RematerializationThreshold)
1993 continue;
1994
1995 // Remove value from the live set
1996 LiveValuesToBeDeleted.push_back(LiveValue);
1997
1998 // Clone instructions and record them inside "Info" structure
1999
2000 // Walk backwards to visit top-most instructions first
2001 std::reverse(ChainToBase.begin(), ChainToBase.end());
2002
2003 // Utility function which clones all instructions from "ChainToBase"
2004 // and inserts them before "InsertBefore". Returns rematerialized value
2005 // which should be used after statepoint.
2006 auto rematerializeChain = [&ChainToBase](
2007 Instruction *InsertBefore, Value *RootOfChain, Value *AlternateLiveBase) {
2008 Instruction *LastClonedValue = nullptr;
2009 Instruction *LastValue = nullptr;
2010 for (Instruction *Instr: ChainToBase) {
2011 // Only GEP's and casts are suported as we need to be careful to not
2012 // introduce any new uses of pointers not in the liveset.
2013 // Note that it's fine to introduce new uses of pointers which were
2014 // otherwise not used after this statepoint.
2015 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2015, __PRETTY_FUNCTION__))
;
2016
2017 Instruction *ClonedValue = Instr->clone();
2018 ClonedValue->insertBefore(InsertBefore);
2019 ClonedValue->setName(Instr->getName() + ".remat");
2020
2021 // If it is not first instruction in the chain then it uses previously
2022 // cloned value. We should update it to use cloned value.
2023 if (LastClonedValue) {
2024 assert(LastValue)((LastValue) ? static_cast<void> (0) : __assert_fail ("LastValue"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2024, __PRETTY_FUNCTION__))
;
2025 ClonedValue->replaceUsesOfWith(LastValue, LastClonedValue);
2026#ifndef NDEBUG
2027 for (auto OpValue : ClonedValue->operand_values()) {
2028 // Assert that cloned instruction does not use any instructions from
2029 // this chain other than LastClonedValue
2030 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2031, __PRETTY_FUNCTION__))
2031 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2031, __PRETTY_FUNCTION__))
;
2032 // Assert that the cloned instruction does not use the RootOfChain
2033 // or the AlternateLiveBase.
2034 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2034, __PRETTY_FUNCTION__))
;
2035 }
2036#endif
2037 } else {
2038 // For the first instruction, replace the use of unrelocated base i.e.
2039 // RootOfChain/OrigRootPhi, with the corresponding PHI present in the
2040 // live set. They have been proved to be the same PHI nodes. Note
2041 // that the *only* use of the RootOfChain in the ChainToBase list is
2042 // the first Value in the list.
2043 if (RootOfChain != AlternateLiveBase)
2044 ClonedValue->replaceUsesOfWith(RootOfChain, AlternateLiveBase);
2045 }
2046
2047 LastClonedValue = ClonedValue;
2048 LastValue = Instr;
2049 }
2050 assert(LastClonedValue)((LastClonedValue) ? static_cast<void> (0) : __assert_fail
("LastClonedValue", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2050, __PRETTY_FUNCTION__))
;
2051 return LastClonedValue;
2052 };
2053
2054 // Different cases for calls and invokes. For invokes we need to clone
2055 // instructions both on normal and unwind path.
2056 if (CS.isCall()) {
2057 Instruction *InsertBefore = CS.getInstruction()->getNextNode();
2058 assert(InsertBefore)((InsertBefore) ? static_cast<void> (0) : __assert_fail
("InsertBefore", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2058, __PRETTY_FUNCTION__))
;
2059 Instruction *RematerializedValue = rematerializeChain(
2060 InsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2061 Info.RematerializedValues[RematerializedValue] = LiveValue;
2062 } else {
2063 InvokeInst *Invoke = cast<InvokeInst>(CS.getInstruction());
2064
2065 Instruction *NormalInsertBefore =
2066 &*Invoke->getNormalDest()->getFirstInsertionPt();
2067 Instruction *UnwindInsertBefore =
2068 &*Invoke->getUnwindDest()->getFirstInsertionPt();
2069
2070 Instruction *NormalRematerializedValue = rematerializeChain(
2071 NormalInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2072 Instruction *UnwindRematerializedValue = rematerializeChain(
2073 UnwindInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
2074
2075 Info.RematerializedValues[NormalRematerializedValue] = LiveValue;
2076 Info.RematerializedValues[UnwindRematerializedValue] = LiveValue;
2077 }
2078 }
2079
2080 // Remove rematerializaed values from the live set
2081 for (auto LiveValue: LiveValuesToBeDeleted) {
2082 Info.LiveSet.remove(LiveValue);
2083 }
2084}
2085
2086static bool insertParsePoints(Function &F, DominatorTree &DT,
2087 TargetTransformInfo &TTI,
2088 SmallVectorImpl<CallSite> &ToUpdate) {
2089#ifndef NDEBUG
2090 // sanity check the input
2091 std::set<CallSite> Uniqued;
2092 Uniqued.insert(ToUpdate.begin(), ToUpdate.end());
2093 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2093, __PRETTY_FUNCTION__))
;
2094
2095 for (CallSite CS : ToUpdate)
2096 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2096, __PRETTY_FUNCTION__))
;
2097#endif
2098
2099 // When inserting gc.relocates for invokes, we need to be able to insert at
2100 // the top of the successor blocks. See the comment on
2101 // normalForInvokeSafepoint on exactly what is needed. Note that this step
2102 // may restructure the CFG.
2103 for (CallSite CS : ToUpdate) {
2104 if (!CS.isInvoke())
2105 continue;
2106 auto *II = cast<InvokeInst>(CS.getInstruction());
2107 normalizeForInvokeSafepoint(II->getNormalDest(), II->getParent(), DT);
2108 normalizeForInvokeSafepoint(II->getUnwindDest(), II->getParent(), DT);
2109 }
2110
2111 // A list of dummy calls added to the IR to keep various values obviously
2112 // live in the IR. We'll remove all of these when done.
2113 SmallVector<CallInst *, 64> Holders;
2114
2115 // Insert a dummy call with all of the arguments to the vm_state we'll need
2116 // for the actual safepoint insertion. This ensures reference arguments in
2117 // the deopt argument list are considered live through the safepoint (and
2118 // thus makes sure they get relocated.)
2119 for (CallSite CS : ToUpdate) {
2120 SmallVector<Value *, 64> DeoptValues;
2121
2122 for (Value *Arg : GetDeoptBundleOperands(CS)) {
2123 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2124, __PRETTY_FUNCTION__))
2124 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2124, __PRETTY_FUNCTION__))
;
2125 if (isHandledGCPointerType(Arg->getType()))
2126 DeoptValues.push_back(Arg);
2127 }
2128
2129 insertUseHolderAfter(CS, DeoptValues, Holders);
2130 }
2131
2132 SmallVector<PartiallyConstructedSafepointRecord, 64> Records(ToUpdate.size());
2133
2134 // A) Identify all gc pointers which are statically live at the given call
2135 // site.
2136 findLiveReferences(F, DT, ToUpdate, Records);
2137
2138 // B) Find the base pointers for each live pointer
2139 /* scope for caching */ {
2140 // Cache the 'defining value' relation used in the computation and
2141 // insertion of base phis and selects. This ensures that we don't insert
2142 // large numbers of duplicate base_phis.
2143 DefiningValueMapTy DVCache;
2144
2145 for (size_t i = 0; i < Records.size(); i++) {
2146 PartiallyConstructedSafepointRecord &info = Records[i];
2147 findBasePointers(DT, DVCache, ToUpdate[i], info);
2148 }
2149 } // end of cache scope
2150
2151 // The base phi insertion logic (for any safepoint) may have inserted new
2152 // instructions which are now live at some safepoint. The simplest such
2153 // example is:
2154 // loop:
2155 // phi a <-- will be a new base_phi here
2156 // safepoint 1 <-- that needs to be live here
2157 // gep a + 1
2158 // safepoint 2
2159 // br loop
2160 // We insert some dummy calls after each safepoint to definitely hold live
2161 // the base pointers which were identified for that safepoint. We'll then
2162 // ask liveness for _every_ base inserted to see what is now live. Then we
2163 // remove the dummy calls.
2164 Holders.reserve(Holders.size() + Records.size());
2165 for (size_t i = 0; i < Records.size(); i++) {
2166 PartiallyConstructedSafepointRecord &Info = Records[i];
2167
2168 SmallVector<Value *, 128> Bases;
2169 for (auto Pair : Info.PointerToBase)
2170 Bases.push_back(Pair.second);
2171
2172 insertUseHolderAfter(ToUpdate[i], Bases, Holders);
2173 }
2174
2175 // By selecting base pointers, we've effectively inserted new uses. Thus, we
2176 // need to rerun liveness. We may *also* have inserted new defs, but that's
2177 // not the key issue.
2178 recomputeLiveInValues(F, DT, ToUpdate, Records);
2179
2180 if (PrintBasePointers) {
2181 for (auto &Info : Records) {
2182 errs() << "Base Pairs: (w/Relocation)\n";
2183 for (auto Pair : Info.PointerToBase) {
2184 errs() << " derived ";
2185 Pair.first->printAsOperand(errs(), false);
2186 errs() << " base ";
2187 Pair.second->printAsOperand(errs(), false);
2188 errs() << "\n";
2189 }
2190 }
2191 }
2192
2193 // It is possible that non-constant live variables have a constant base. For
2194 // example, a GEP with a variable offset from a global. In this case we can
2195 // remove it from the liveset. We already don't add constants to the liveset
2196 // because we assume they won't move at runtime and the GC doesn't need to be
2197 // informed about them. The same reasoning applies if the base is constant.
2198 // Note that the relocation placement code relies on this filtering for
2199 // correctness as it expects the base to be in the liveset, which isn't true
2200 // if the base is constant.
2201 for (auto &Info : Records)
2202 for (auto &BasePair : Info.PointerToBase)
2203 if (isa<Constant>(BasePair.second))
2204 Info.LiveSet.remove(BasePair.first);
2205
2206 for (CallInst *CI : Holders)
2207 CI->eraseFromParent();
2208
2209 Holders.clear();
2210
2211 // In order to reduce live set of statepoint we might choose to rematerialize
2212 // some values instead of relocating them. This is purely an optimization and
2213 // does not influence correctness.
2214 for (size_t i = 0; i < Records.size(); i++)
2215 rematerializeLiveValues(ToUpdate[i], Records[i], TTI);
2216
2217 // We need this to safely RAUW and delete call or invoke return values that
2218 // may themselves be live over a statepoint. For details, please see usage in
2219 // makeStatepointExplicitImpl.
2220 std::vector<DeferredReplacement> Replacements;
2221
2222 // Now run through and replace the existing statepoints with new ones with
2223 // the live variables listed. We do not yet update uses of the values being
2224 // relocated. We have references to live variables that need to
2225 // survive to the last iteration of this loop. (By construction, the
2226 // previous statepoint can not be a live variable, thus we can and remove
2227 // the old statepoint calls as we go.)
2228 for (size_t i = 0; i < Records.size(); i++)
2229 makeStatepointExplicit(DT, ToUpdate[i], Records[i], Replacements);
2230
2231 ToUpdate.clear(); // prevent accident use of invalid CallSites
2232
2233 for (auto &PR : Replacements)
2234 PR.doReplacement();
2235
2236 Replacements.clear();
2237
2238 for (auto &Info : Records) {
2239 // These live sets may contain state Value pointers, since we replaced calls
2240 // with operand bundles with calls wrapped in gc.statepoint, and some of
2241 // those calls may have been def'ing live gc pointers. Clear these out to
2242 // avoid accidentally using them.
2243 //
2244 // TODO: We should create a separate data structure that does not contain
2245 // these live sets, and migrate to using that data structure from this point
2246 // onward.
2247 Info.LiveSet.clear();
2248 Info.PointerToBase.clear();
2249 }
2250
2251 // Do all the fixups of the original live variables to their relocated selves
2252 SmallVector<Value *, 128> Live;
2253 for (size_t i = 0; i < Records.size(); i++) {
2254 PartiallyConstructedSafepointRecord &Info = Records[i];
2255
2256 // We can't simply save the live set from the original insertion. One of
2257 // the live values might be the result of a call which needs a safepoint.
2258 // That Value* no longer exists and we need to use the new gc_result.
2259 // Thankfully, the live set is embedded in the statepoint (and updated), so
2260 // we just grab that.
2261 Statepoint Statepoint(Info.StatepointToken);
2262 Live.insert(Live.end(), Statepoint.gc_args_begin(),
2263 Statepoint.gc_args_end());
2264#ifndef NDEBUG
2265 // Do some basic sanity checks on our liveness results before performing
2266 // relocation. Relocation can and will turn mistakes in liveness results
2267 // into non-sensical code which is must harder to debug.
2268 // TODO: It would be nice to test consistency as well
2269 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2270, __PRETTY_FUNCTION__))
2270 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2270, __PRETTY_FUNCTION__))
;
2271 for (Value *V : Statepoint.gc_args()) {
2272 if (!isa<Instruction>(V))
2273 // Non-instruction values trivial dominate all possible uses
2274 continue;
2275 auto *LiveInst = cast<Instruction>(V);
2276 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2277, __PRETTY_FUNCTION__))
2277 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2277, __PRETTY_FUNCTION__))
;
2278 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2279, __PRETTY_FUNCTION__))
2279 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2279, __PRETTY_FUNCTION__))
;
2280 }
2281#endif
2282 }
2283 unique_unsorted(Live);
2284
2285#ifndef NDEBUG
2286 // sanity check
2287 for (auto *Ptr : Live)
2288 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2289, __PRETTY_FUNCTION__))
2289 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2289, __PRETTY_FUNCTION__))
;
2290#endif
2291
2292 relocationViaAlloca(F, DT, Live, Records);
2293 return !Records.empty();
2294}
2295
2296// Handles both return values and arguments for Functions and CallSites.
2297template <typename AttrHolder>
2298static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
2299 unsigned Index) {
2300 AttrBuilder R;
2301 if (AH.getDereferenceableBytes(Index))
2302 R.addAttribute(Attribute::get(Ctx, Attribute::Dereferenceable,
2303 AH.getDereferenceableBytes(Index)));
2304 if (AH.getDereferenceableOrNullBytes(Index))
2305 R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull,
2306 AH.getDereferenceableOrNullBytes(Index)));
2307 if (AH.doesNotAlias(Index))
2308 R.addAttribute(Attribute::NoAlias);
2309
2310 if (!R.empty())
2311 AH.setAttributes(AH.getAttributes().removeAttributes(
2312 Ctx, Index, AttributeSet::get(Ctx, Index, R)));
2313}
2314
2315void
2316RewriteStatepointsForGC::stripNonValidAttributesFromPrototype(Function &F) {
2317 LLVMContext &Ctx = F.getContext();
2318
2319 for (Argument &A : F.args())
2320 if (isa<PointerType>(A.getType()))
2321 RemoveNonValidAttrAtIndex(Ctx, F, A.getArgNo() + 1);
2322
2323 if (isa<PointerType>(F.getReturnType()))
2324 RemoveNonValidAttrAtIndex(Ctx, F, AttributeSet::ReturnIndex);
2325}
2326
2327void RewriteStatepointsForGC::stripNonValidAttributesFromBody(Function &F) {
2328 if (F.empty())
2329 return;
2330
2331 LLVMContext &Ctx = F.getContext();
2332 MDBuilder Builder(Ctx);
2333
2334 for (Instruction &I : instructions(F)) {
2335 if (const MDNode *MD = I.getMetadata(LLVMContext::MD_tbaa)) {
2336 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2336, __PRETTY_FUNCTION__))
;
2337 bool IsImmutableTBAA =
2338 MD->getNumOperands() == 4 &&
2339 mdconst::extract<ConstantInt>(MD->getOperand(3))->getValue() == 1;
2340
2341 if (!IsImmutableTBAA)
2342 continue; // no work to do, MD_tbaa is already marked mutable
2343
2344 MDNode *Base = cast<MDNode>(MD->getOperand(0));
2345 MDNode *Access = cast<MDNode>(MD->getOperand(1));
2346 uint64_t Offset =
2347 mdconst::extract<ConstantInt>(MD->getOperand(2))->getZExtValue();
2348
2349 MDNode *MutableTBAA =
2350 Builder.createTBAAStructTagNode(Base, Access, Offset);
2351 I.setMetadata(LLVMContext::MD_tbaa, MutableTBAA);
2352 }
2353
2354 if (CallSite CS = CallSite(&I)) {
2355 for (int i = 0, e = CS.arg_size(); i != e; i++)
2356 if (isa<PointerType>(CS.getArgument(i)->getType()))
2357 RemoveNonValidAttrAtIndex(Ctx, CS, i + 1);
2358 if (isa<PointerType>(CS.getType()))
2359 RemoveNonValidAttrAtIndex(Ctx, CS, AttributeSet::ReturnIndex);
2360 }
2361 }
2362}
2363
2364/// Returns true if this function should be rewritten by this pass. The main
2365/// point of this function is as an extension point for custom logic.
2366static bool shouldRewriteStatepointsIn(Function &F) {
2367 // TODO: This should check the GCStrategy
2368 if (F.hasGC()) {
2369 const auto &FunctionGCName = F.getGC();
2370 const StringRef StatepointExampleName("statepoint-example");
2371 const StringRef CoreCLRName("coreclr");
2372 return (StatepointExampleName == FunctionGCName) ||
2373 (CoreCLRName == FunctionGCName);
2374 } else
2375 return false;
2376}
2377
2378void RewriteStatepointsForGC::stripNonValidAttributes(Module &M) {
2379#ifndef NDEBUG
2380 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2380, __PRETTY_FUNCTION__))
;
2381#endif
2382
2383 for (Function &F : M)
2384 stripNonValidAttributesFromPrototype(F);
2385
2386 for (Function &F : M)
2387 stripNonValidAttributesFromBody(F);
2388}
2389
2390bool RewriteStatepointsForGC::runOnFunction(Function &F) {
2391 // Nothing to do for declarations.
2392 if (F.isDeclaration() || F.empty())
2393 return false;
2394
2395 // Policy choice says not to rewrite - the most common reason is that we're
2396 // compiling code without a GCStrategy.
2397 if (!shouldRewriteStatepointsIn(F))
2398 return false;
2399
2400 DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
2401 TargetTransformInfo &TTI =
2402 getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
2403
2404 auto NeedsRewrite = [](Instruction &I) {
2405 if (ImmutableCallSite CS = ImmutableCallSite(&I))
2406 return !callsGCLeafFunction(CS) && !isStatepoint(CS);
2407 return false;
2408 };
2409
2410 // Gather all the statepoints which need rewritten. Be careful to only
2411 // consider those in reachable code since we need to ask dominance queries
2412 // when rewriting. We'll delete the unreachable ones in a moment.
2413 SmallVector<CallSite, 64> ParsePointNeeded;
2414 bool HasUnreachableStatepoint = false;
2415 for (Instruction &I : instructions(F)) {
2416 // TODO: only the ones with the flag set!
2417 if (NeedsRewrite(I)) {
2418 if (DT.isReachableFromEntry(I.getParent()))
2419 ParsePointNeeded.push_back(CallSite(&I));
2420 else
2421 HasUnreachableStatepoint = true;
2422 }
2423 }
2424
2425 bool MadeChange = false;
2426
2427 // Delete any unreachable statepoints so that we don't have unrewritten
2428 // statepoints surviving this pass. This makes testing easier and the
2429 // resulting IR less confusing to human readers. Rather than be fancy, we
2430 // just reuse a utility function which removes the unreachable blocks.
2431 if (HasUnreachableStatepoint)
2432 MadeChange |= removeUnreachableBlocks(F);
2433
2434 // Return early if no work to do.
2435 if (ParsePointNeeded.empty())
2436 return MadeChange;
2437
2438 // As a prepass, go ahead and aggressively destroy single entry phi nodes.
2439 // These are created by LCSSA. They have the effect of increasing the size
2440 // of liveness sets for no good reason. It may be harder to do this post
2441 // insertion since relocations and base phis can confuse things.
2442 for (BasicBlock &BB : F)
2443 if (BB.getUniquePredecessor()) {
2444 MadeChange = true;
2445 FoldSingleEntryPHINodes(&BB);
2446 }
2447
2448 // Before we start introducing relocations, we want to tweak the IR a bit to
2449 // avoid unfortunate code generation effects. The main example is that we
2450 // want to try to make sure the comparison feeding a branch is after any
2451 // safepoints. Otherwise, we end up with a comparison of pre-relocation
2452 // values feeding a branch after relocation. This is semantically correct,
2453 // but results in extra register pressure since both the pre-relocation and
2454 // post-relocation copies must be available in registers. For code without
2455 // relocations this is handled elsewhere, but teaching the scheduler to
2456 // reverse the transform we're about to do would be slightly complex.
2457 // Note: This may extend the live range of the inputs to the icmp and thus
2458 // increase the liveset of any statepoint we move over. This is profitable
2459 // as long as all statepoints are in rare blocks. If we had in-register
2460 // lowering for live values this would be a much safer transform.
2461 auto getConditionInst = [](TerminatorInst *TI) -> Instruction* {
2462 if (auto *BI = dyn_cast<BranchInst>(TI))
2463 if (BI->isConditional())
2464 return dyn_cast<Instruction>(BI->getCondition());
2465 // TODO: Extend this to handle switches
2466 return nullptr;
2467 };
2468 for (BasicBlock &BB : F) {
2469 TerminatorInst *TI = BB.getTerminator();
2470 if (auto *Cond = getConditionInst(TI))
2471 // TODO: Handle more than just ICmps here. We should be able to move
2472 // most instructions without side effects or memory access.
2473 if (isa<ICmpInst>(Cond) && Cond->hasOneUse()) {
2474 MadeChange = true;
2475 Cond->moveBefore(TI);
2476 }
2477 }
2478
2479 MadeChange |= insertParsePoints(F, DT, TTI, ParsePointNeeded);
2480 return MadeChange;
2481}
2482
2483// liveness computation via standard dataflow
2484// -------------------------------------------------------------------
2485
2486// TODO: Consider using bitvectors for liveness, the set of potentially
2487// interesting values should be small and easy to pre-compute.
2488
2489/// Compute the live-in set for the location rbegin starting from
2490/// the live-out set of the basic block
2491static void computeLiveInValues(BasicBlock::reverse_iterator Begin,
2492 BasicBlock::reverse_iterator End,
2493 SetVector<Value *> &LiveTmp) {
2494 for (auto &I : make_range(Begin, End)) {
2495 // KILL/Def - Remove this definition from LiveIn
2496 LiveTmp.remove(&I);
2497
2498 // Don't consider *uses* in PHI nodes, we handle their contribution to
2499 // predecessor blocks when we seed the LiveOut sets
2500 if (isa<PHINode>(I))
2501 continue;
2502
2503 // USE - Add to the LiveIn set for this instruction
2504 for (Value *V : I.operands()) {
2505 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2506, __PRETTY_FUNCTION__))
2506 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2506, __PRETTY_FUNCTION__))
;
2507 if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V)) {
2508 // The choice to exclude all things constant here is slightly subtle.
2509 // There are two independent reasons:
2510 // - We assume that things which are constant (from LLVM's definition)
2511 // do not move at runtime. For example, the address of a global
2512 // variable is fixed, even though it's contents may not be.
2513 // - Second, we can't disallow arbitrary inttoptr constants even
2514 // if the language frontend does. Optimization passes are free to
2515 // locally exploit facts without respect to global reachability. This
2516 // can create sections of code which are dynamically unreachable and
2517 // contain just about anything. (see constants.ll in tests)
2518 LiveTmp.insert(V);
2519 }
2520 }
2521 }
2522}
2523
2524static void computeLiveOutSeed(BasicBlock *BB, SetVector<Value *> &LiveTmp) {
2525 for (BasicBlock *Succ : successors(BB)) {
2526 for (auto &I : *Succ) {
2527 PHINode *PN = dyn_cast<PHINode>(&I);
2528 if (!PN)
2529 break;
2530
2531 Value *V = PN->getIncomingValueForBlock(BB);
2532 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2533, __PRETTY_FUNCTION__))
2533 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2533, __PRETTY_FUNCTION__))
;
2534 if (isHandledGCPointerType(V->getType()) && !isa<Constant>(V))
2535 LiveTmp.insert(V);
2536 }
2537 }
2538}
2539
2540static SetVector<Value *> computeKillSet(BasicBlock *BB) {
2541 SetVector<Value *> KillSet;
2542 for (Instruction &I : *BB)
2543 if (isHandledGCPointerType(I.getType()))
2544 KillSet.insert(&I);
2545 return KillSet;
2546}
2547
2548#ifndef NDEBUG
2549/// Check that the items in 'Live' dominate 'TI'. This is used as a basic
2550/// sanity check for the liveness computation.
2551static void checkBasicSSA(DominatorTree &DT, SetVector<Value *> &Live,
2552 TerminatorInst *TI, bool TermOkay = false) {
2553 for (Value *V : Live) {
2554 if (auto *I = dyn_cast<Instruction>(V)) {
2555 // The terminator can be a member of the LiveOut set. LLVM's definition
2556 // of instruction dominance states that V does not dominate itself. As
2557 // such, we need to special case this to allow it.
2558 if (TermOkay && TI == I)
2559 continue;
2560 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2561, __PRETTY_FUNCTION__))
2561 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2561, __PRETTY_FUNCTION__))
;
2562 }
2563 }
2564}
2565
2566/// Check that all the liveness sets used during the computation of liveness
2567/// obey basic SSA properties. This is useful for finding cases where we miss
2568/// a def.
2569static void checkBasicSSA(DominatorTree &DT, GCPtrLivenessData &Data,
2570 BasicBlock &BB) {
2571 checkBasicSSA(DT, Data.LiveSet[&BB], BB.getTerminator());
2572 checkBasicSSA(DT, Data.LiveOut[&BB], BB.getTerminator(), true);
2573 checkBasicSSA(DT, Data.LiveIn[&BB], BB.getTerminator());
2574}
2575#endif
2576
2577static void computeLiveInValues(DominatorTree &DT, Function &F,
2578 GCPtrLivenessData &Data) {
2579 SmallSetVector<BasicBlock *, 32> Worklist;
2580
2581 // Seed the liveness for each individual block
2582 for (BasicBlock &BB : F) {
2583 Data.KillSet[&BB] = computeKillSet(&BB);
2584 Data.LiveSet[&BB].clear();
2585 computeLiveInValues(BB.rbegin(), BB.rend(), Data.LiveSet[&BB]);
2586
2587#ifndef NDEBUG
2588 for (Value *Kill : Data.KillSet[&BB])
2589 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2589, __PRETTY_FUNCTION__))
;
2590#endif
2591
2592 Data.LiveOut[&BB] = SetVector<Value *>();
2593 computeLiveOutSeed(&BB, Data.LiveOut[&BB]);
2594 Data.LiveIn[&BB] = Data.LiveSet[&BB];
2595 Data.LiveIn[&BB].set_union(Data.LiveOut[&BB]);
2596 Data.LiveIn[&BB].set_subtract(Data.KillSet[&BB]);
2597 if (!Data.LiveIn[&BB].empty())
2598 Worklist.insert(pred_begin(&BB), pred_end(&BB));
2599 }
2600
2601 // Propagate that liveness until stable
2602 while (!Worklist.empty()) {
2603 BasicBlock *BB = Worklist.pop_back_val();
2604
2605 // Compute our new liveout set, then exit early if it hasn't changed despite
2606 // the contribution of our successor.
2607 SetVector<Value *> LiveOut = Data.LiveOut[BB];
2608 const auto OldLiveOutSize = LiveOut.size();
2609 for (BasicBlock *Succ : successors(BB)) {
2610 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2610, __PRETTY_FUNCTION__))
;
2611 LiveOut.set_union(Data.LiveIn[Succ]);
2612 }
2613 // assert OutLiveOut is a subset of LiveOut
2614 if (OldLiveOutSize == LiveOut.size()) {
2615 // If the sets are the same size, then we didn't actually add anything
2616 // when unioning our successors LiveIn. Thus, the LiveIn of this block
2617 // hasn't changed.
2618 continue;
2619 }
2620 Data.LiveOut[BB] = LiveOut;
2621
2622 // Apply the effects of this basic block
2623 SetVector<Value *> LiveTmp = LiveOut;
2624 LiveTmp.set_union(Data.LiveSet[BB]);
2625 LiveTmp.set_subtract(Data.KillSet[BB]);
2626
2627 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2627, __PRETTY_FUNCTION__))
;
2628 const SetVector<Value *> &OldLiveIn = Data.LiveIn[BB];
2629 // assert: OldLiveIn is a subset of LiveTmp
2630 if (OldLiveIn.size() != LiveTmp.size()) {
2631 Data.LiveIn[BB] = LiveTmp;
2632 Worklist.insert(pred_begin(BB), pred_end(BB));
2633 }
2634 } // while (!Worklist.empty())
2635
2636#ifndef NDEBUG
2637 // Sanity check our output against SSA properties. This helps catch any
2638 // missing kills during the above iteration.
2639 for (BasicBlock &BB : F)
2640 checkBasicSSA(DT, Data, BB);
2641#endif
2642}
2643
2644static void findLiveSetAtInst(Instruction *Inst, GCPtrLivenessData &Data,
2645 StatepointLiveSetTy &Out) {
2646
2647 BasicBlock *BB = Inst->getParent();
2648
2649 // Note: The copy is intentional and required
2650 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2650, __PRETTY_FUNCTION__))
;
2651 SetVector<Value *> LiveOut = Data.LiveOut[BB];
2652
2653 // We want to handle the statepoint itself oddly. It's
2654 // call result is not live (normal), nor are it's arguments
2655 // (unless they're used again later). This adjustment is
2656 // specifically what we need to relocate
2657 computeLiveInValues(BB->rbegin(), ++Inst->getIterator().getReverse(),
2658 LiveOut);
2659 LiveOut.remove(Inst);
2660 Out.insert(LiveOut.begin(), LiveOut.end());
2661}
2662
2663static void recomputeLiveInValues(GCPtrLivenessData &RevisedLivenessData,
2664 CallSite CS,
2665 PartiallyConstructedSafepointRecord &Info) {
2666 Instruction *Inst = CS.getInstruction();
2667 StatepointLiveSetTy Updated;
2668 findLiveSetAtInst(Inst, RevisedLivenessData, Updated);
2669
2670#ifndef NDEBUG
2671 DenseSet<Value *> Bases;
2672 for (auto KVPair : Info.PointerToBase)
2673 Bases.insert(KVPair.second);
2674#endif
2675
2676 // We may have base pointers which are now live that weren't before. We need
2677 // to update the PointerToBase structure to reflect this.
2678 for (auto V : Updated)
2679 if (Info.PointerToBase.insert({V, V}).second) {
2680 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2680, __PRETTY_FUNCTION__))
;
2681 continue;
2682 }
2683
2684#ifndef NDEBUG
2685 for (auto V : Updated)
2686 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2687, __PRETTY_FUNCTION__))
2687 "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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2687, __PRETTY_FUNCTION__))
;
2688#endif
2689
2690 // Remove any stale base mappings - this can happen since our liveness is
2691 // more precise then the one inherent in the base pointer analysis.
2692 DenseSet<Value *> ToErase;
2693 for (auto KVPair : Info.PointerToBase)
2694 if (!Updated.count(KVPair.first))
2695 ToErase.insert(KVPair.first);
2696
2697 for (auto *V : ToErase)
2698 Info.PointerToBase.erase(V);
2699
2700#ifndef NDEBUG
2701 for (auto KVPair : Info.PointerToBase)
2702 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~svn298304/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp"
, 2702, __PRETTY_FUNCTION__))
;
2703#endif
2704
2705 Info.LiveSet = Updated;
2706}