Bug Summary

File:lib/CodeGen/WinEHPrepare.cpp
Location:line 1743, column 7
Description:Called C++ object pointer is null

Annotated Source Code

1//===-- WinEHPrepare - Prepare exception handling for code generation ---===//
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// This pass lowers LLVM IR exception handling into something closer to what the
11// backend wants. It snifs the personality function to see which kind of
12// preparation is necessary. If the personality function uses the Itanium LSDA,
13// this pass delegates to the DWARF EH preparation pass.
14//
15//===----------------------------------------------------------------------===//
16
17#include "llvm/CodeGen/Passes.h"
18#include "llvm/ADT/MapVector.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallSet.h"
21#include "llvm/ADT/SetVector.h"
22#include "llvm/ADT/TinyPtrVector.h"
23#include "llvm/Analysis/LibCallSemantics.h"
24#include "llvm/CodeGen/WinEHFuncInfo.h"
25#include "llvm/IR/Dominators.h"
26#include "llvm/IR/Function.h"
27#include "llvm/IR/IRBuilder.h"
28#include "llvm/IR/Instructions.h"
29#include "llvm/IR/IntrinsicInst.h"
30#include "llvm/IR/Module.h"
31#include "llvm/IR/PatternMatch.h"
32#include "llvm/Pass.h"
33#include "llvm/Support/CommandLine.h"
34#include "llvm/Support/Debug.h"
35#include "llvm/Support/raw_ostream.h"
36#include "llvm/Transforms/Utils/BasicBlockUtils.h"
37#include "llvm/Transforms/Utils/Cloning.h"
38#include "llvm/Transforms/Utils/Local.h"
39#include "llvm/Transforms/Utils/PromoteMemToReg.h"
40#include <memory>
41
42using namespace llvm;
43using namespace llvm::PatternMatch;
44
45#define DEBUG_TYPE"winehprepare" "winehprepare"
46
47namespace {
48
49// This map is used to model frame variable usage during outlining, to
50// construct a structure type to hold the frame variables in a frame
51// allocation block, and to remap the frame variable allocas (including
52// spill locations as needed) to GEPs that get the variable from the
53// frame allocation structure.
54typedef MapVector<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap;
55
56// TinyPtrVector cannot hold nullptr, so we need our own sentinel that isn't
57// quite null.
58AllocaInst *getCatchObjectSentinel() {
59 return static_cast<AllocaInst *>(nullptr) + 1;
60}
61
62typedef SmallSet<BasicBlock *, 4> VisitedBlockSet;
63
64class LandingPadActions;
65class LandingPadMap;
66
67typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy;
68typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy;
69
70class WinEHPrepare : public FunctionPass {
71public:
72 static char ID; // Pass identification, replacement for typeid.
73 WinEHPrepare(const TargetMachine *TM = nullptr)
74 : FunctionPass(ID), DT(nullptr), SEHExceptionCodeSlot(nullptr) {}
75
76 bool runOnFunction(Function &Fn) override;
77
78 bool doFinalization(Module &M) override;
79
80 void getAnalysisUsage(AnalysisUsage &AU) const override;
81
82 const char *getPassName() const override {
83 return "Windows exception handling preparation";
84 }
85
86private:
87 bool prepareExceptionHandlers(Function &F,
88 SmallVectorImpl<LandingPadInst *> &LPads);
89 void promoteLandingPadValues(LandingPadInst *LPad);
90 void demoteValuesLiveAcrossHandlers(Function &F,
91 SmallVectorImpl<LandingPadInst *> &LPads);
92 void completeNestedLandingPad(Function *ParentFn,
93 LandingPadInst *OutlinedLPad,
94 const LandingPadInst *OriginalLPad,
95 FrameVarInfoMap &VarInfo);
96 bool outlineHandler(ActionHandler *Action, Function *SrcFn,
97 LandingPadInst *LPad, BasicBlock *StartBB,
98 FrameVarInfoMap &VarInfo);
99 void addStubInvokeToHandlerIfNeeded(Function *Handler, Value *PersonalityFn);
100
101 void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions);
102 CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB,
103 VisitedBlockSet &VisitedBlocks);
104 void findCleanupHandlers(LandingPadActions &Actions, BasicBlock *StartBB,
105 BasicBlock *EndBB);
106
107 void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
108
109 // All fields are reset by runOnFunction.
110 DominatorTree *DT;
111 EHPersonality Personality;
112 CatchHandlerMapTy CatchHandlerMap;
113 CleanupHandlerMapTy CleanupHandlerMap;
114 DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps;
115
116 // This maps landing pad instructions found in outlined handlers to
117 // the landing pad instruction in the parent function from which they
118 // were cloned. The cloned/nested landing pad is used as the key
119 // because the landing pad may be cloned into multiple handlers.
120 // This map will be used to add the llvm.eh.actions call to the nested
121 // landing pads after all handlers have been outlined.
122 DenseMap<LandingPadInst *, const LandingPadInst *> NestedLPtoOriginalLP;
123
124 // This maps blocks in the parent function which are destinations of
125 // catch handlers to cloned blocks in (other) outlined handlers. This
126 // handles the case where a nested landing pads has a catch handler that
127 // returns to a handler function rather than the parent function.
128 // The original block is used as the key here because there should only
129 // ever be one handler function from which the cloned block is not pruned.
130 // The original block will be pruned from the parent function after all
131 // handlers have been outlined. This map will be used to adjust the
132 // return instructions of handlers which return to the block that was
133 // outlined into a handler. This is done after all handlers have been
134 // outlined but before the outlined code is pruned from the parent function.
135 DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
136
137 AllocaInst *SEHExceptionCodeSlot;
138};
139
140class WinEHFrameVariableMaterializer : public ValueMaterializer {
141public:
142 WinEHFrameVariableMaterializer(Function *OutlinedFn,
143 FrameVarInfoMap &FrameVarInfo);
144 ~WinEHFrameVariableMaterializer() override {}
145
146 Value *materializeValueFor(Value *V) override;
147
148 void escapeCatchObject(Value *V);
149
150private:
151 FrameVarInfoMap &FrameVarInfo;
152 IRBuilder<> Builder;
153};
154
155class LandingPadMap {
156public:
157 LandingPadMap() : OriginLPad(nullptr) {}
158 void mapLandingPad(const LandingPadInst *LPad);
159
160 bool isInitialized() { return OriginLPad != nullptr; }
161
162 bool isOriginLandingPadBlock(const BasicBlock *BB) const;
163 bool isLandingPadSpecificInst(const Instruction *Inst) const;
164
165 void remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
166 Value *SelectorValue) const;
167
168private:
169 const LandingPadInst *OriginLPad;
170 // We will normally only see one of each of these instructions, but
171 // if more than one occurs for some reason we can handle that.
172 TinyPtrVector<const ExtractValueInst *> ExtractedEHPtrs;
173 TinyPtrVector<const ExtractValueInst *> ExtractedSelectors;
174};
175
176class WinEHCloningDirectorBase : public CloningDirector {
177public:
178 WinEHCloningDirectorBase(Function *HandlerFn, FrameVarInfoMap &VarInfo,
179 LandingPadMap &LPadMap)
180 : Materializer(HandlerFn, VarInfo),
181 SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
182 Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())),
183 LPadMap(LPadMap) {
184 auto AI = HandlerFn->getArgumentList().begin();
185 ++AI;
186 EstablisherFrame = AI;
187 }
188
189 CloningAction handleInstruction(ValueToValueMapTy &VMap,
190 const Instruction *Inst,
191 BasicBlock *NewBB) override;
192
193 virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
194 const Instruction *Inst,
195 BasicBlock *NewBB) = 0;
196 virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap,
197 const Instruction *Inst,
198 BasicBlock *NewBB) = 0;
199 virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
200 const Instruction *Inst,
201 BasicBlock *NewBB) = 0;
202 virtual CloningAction handleInvoke(ValueToValueMapTy &VMap,
203 const InvokeInst *Invoke,
204 BasicBlock *NewBB) = 0;
205 virtual CloningAction handleResume(ValueToValueMapTy &VMap,
206 const ResumeInst *Resume,
207 BasicBlock *NewBB) = 0;
208 virtual CloningAction handleCompare(ValueToValueMapTy &VMap,
209 const CmpInst *Compare,
210 BasicBlock *NewBB) = 0;
211 virtual CloningAction handleLandingPad(ValueToValueMapTy &VMap,
212 const LandingPadInst *LPad,
213 BasicBlock *NewBB) = 0;
214
215 ValueMaterializer *getValueMaterializer() override { return &Materializer; }
216
217protected:
218 WinEHFrameVariableMaterializer Materializer;
219 Type *SelectorIDType;
220 Type *Int8PtrType;
221 LandingPadMap &LPadMap;
222
223 /// The value representing the parent frame pointer.
224 Value *EstablisherFrame;
225};
226
227class WinEHCatchDirector : public WinEHCloningDirectorBase {
228public:
229 WinEHCatchDirector(
230 Function *CatchFn, Value *Selector, FrameVarInfoMap &VarInfo,
231 LandingPadMap &LPadMap,
232 DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads)
233 : WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap),
234 CurrentSelector(Selector->stripPointerCasts()),
235 ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads) {}
236
237 CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
238 const Instruction *Inst,
239 BasicBlock *NewBB) override;
240 CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
241 BasicBlock *NewBB) override;
242 CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
243 const Instruction *Inst,
244 BasicBlock *NewBB) override;
245 CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
246 BasicBlock *NewBB) override;
247 CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
248 BasicBlock *NewBB) override;
249 CloningAction handleCompare(ValueToValueMapTy &VMap,
250 const CmpInst *Compare, BasicBlock *NewBB) override;
251 CloningAction handleLandingPad(ValueToValueMapTy &VMap,
252 const LandingPadInst *LPad,
253 BasicBlock *NewBB) override;
254
255 Value *getExceptionVar() { return ExceptionObjectVar; }
256 TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
257
258private:
259 Value *CurrentSelector;
260
261 Value *ExceptionObjectVar;
262 TinyPtrVector<BasicBlock *> ReturnTargets;
263
264 // This will be a reference to the field of the same name in the WinEHPrepare
265 // object which instantiates this WinEHCatchDirector object.
266 DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPtoOriginalLP;
267};
268
269class WinEHCleanupDirector : public WinEHCloningDirectorBase {
270public:
271 WinEHCleanupDirector(Function *CleanupFn, FrameVarInfoMap &VarInfo,
272 LandingPadMap &LPadMap)
273 : WinEHCloningDirectorBase(CleanupFn, VarInfo, LPadMap) {}
274
275 CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
276 const Instruction *Inst,
277 BasicBlock *NewBB) override;
278 CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
279 BasicBlock *NewBB) override;
280 CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
281 const Instruction *Inst,
282 BasicBlock *NewBB) override;
283 CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
284 BasicBlock *NewBB) override;
285 CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
286 BasicBlock *NewBB) override;
287 CloningAction handleCompare(ValueToValueMapTy &VMap,
288 const CmpInst *Compare, BasicBlock *NewBB) override;
289 CloningAction handleLandingPad(ValueToValueMapTy &VMap,
290 const LandingPadInst *LPad,
291 BasicBlock *NewBB) override;
292};
293
294class LandingPadActions {
295public:
296 LandingPadActions() : HasCleanupHandlers(false) {}
297
298 void insertCatchHandler(CatchHandler *Action) { Actions.push_back(Action); }
299 void insertCleanupHandler(CleanupHandler *Action) {
300 Actions.push_back(Action);
301 HasCleanupHandlers = true;
302 }
303
304 bool includesCleanup() const { return HasCleanupHandlers; }
305
306 SmallVectorImpl<ActionHandler *> &actions() { return Actions; }
307 SmallVectorImpl<ActionHandler *>::iterator begin() { return Actions.begin(); }
308 SmallVectorImpl<ActionHandler *>::iterator end() { return Actions.end(); }
309
310private:
311 // Note that this class does not own the ActionHandler objects in this vector.
312 // The ActionHandlers are owned by the CatchHandlerMap and CleanupHandlerMap
313 // in the WinEHPrepare class.
314 SmallVector<ActionHandler *, 4> Actions;
315 bool HasCleanupHandlers;
316};
317
318} // end anonymous namespace
319
320char WinEHPrepare::ID = 0;
321INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions",static void* initializeWinEHPreparePassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo("Prepare Windows exceptions"
, "winehprepare", & WinEHPrepare ::ID, PassInfo::NormalCtor_t
(callDefaultCtor< WinEHPrepare >), false, false, PassInfo
::TargetMachineCtor_t(callTargetMachineCtor< WinEHPrepare >
)); Registry.registerPass(*PI, true); return PI; } void llvm::
initializeWinEHPreparePass(PassRegistry &Registry) { static
volatile sys::cas_flag initialized = 0; sys::cas_flag old_val
= sys::CompareAndSwap(&initialized, 1, 0); if (old_val ==
0) { initializeWinEHPreparePassOnce(Registry); sys::MemoryFence
(); AnnotateIgnoreWritesBegin("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322); AnnotateHappensBefore("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322, &initialized); initialized = 2; AnnotateIgnoreWritesEnd
("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322); } else { sys::cas_flag tmp = initialized; sys::MemoryFence
(); while (tmp != 2) { tmp = initialized; sys::MemoryFence();
} } AnnotateHappensAfter("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322, &initialized); }
322 false, false)static void* initializeWinEHPreparePassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo("Prepare Windows exceptions"
, "winehprepare", & WinEHPrepare ::ID, PassInfo::NormalCtor_t
(callDefaultCtor< WinEHPrepare >), false, false, PassInfo
::TargetMachineCtor_t(callTargetMachineCtor< WinEHPrepare >
)); Registry.registerPass(*PI, true); return PI; } void llvm::
initializeWinEHPreparePass(PassRegistry &Registry) { static
volatile sys::cas_flag initialized = 0; sys::cas_flag old_val
= sys::CompareAndSwap(&initialized, 1, 0); if (old_val ==
0) { initializeWinEHPreparePassOnce(Registry); sys::MemoryFence
(); AnnotateIgnoreWritesBegin("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322); AnnotateHappensBefore("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322, &initialized); initialized = 2; AnnotateIgnoreWritesEnd
("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322); } else { sys::cas_flag tmp = initialized; sys::MemoryFence
(); while (tmp != 2) { tmp = initialized; sys::MemoryFence();
} } AnnotateHappensAfter("/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 322, &initialized); }
323
324FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) {
325 return new WinEHPrepare(TM);
326}
327
328bool WinEHPrepare::runOnFunction(Function &Fn) {
329 // No need to prepare outlined handlers.
330 if (Fn.hasFnAttribute("wineh-parent"))
331 return false;
332
333 SmallVector<LandingPadInst *, 4> LPads;
334 SmallVector<ResumeInst *, 4> Resumes;
335 for (BasicBlock &BB : Fn) {
336 if (auto *LP = BB.getLandingPadInst())
337 LPads.push_back(LP);
338 if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator()))
339 Resumes.push_back(Resume);
340 }
341
342 // No need to prepare functions that lack landing pads.
343 if (LPads.empty())
344 return false;
345
346 // Classify the personality to see what kind of preparation we need.
347 Personality = classifyEHPersonality(LPads.back()->getPersonalityFn());
348
349 // Do nothing if this is not an MSVC personality.
350 if (!isMSVCEHPersonality(Personality))
351 return false;
352
353 DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
354
355 // If there were any landing pads, prepareExceptionHandlers will make changes.
356 prepareExceptionHandlers(Fn, LPads);
357 return true;
358}
359
360bool WinEHPrepare::doFinalization(Module &M) { return false; }
361
362void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
363 AU.addRequired<DominatorTreeWrapperPass>();
364}
365
366static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
367 Constant *&Selector, BasicBlock *&NextBB);
368
369// Finds blocks reachable from the starting set Worklist. Does not follow unwind
370// edges or blocks listed in StopPoints.
371static void findReachableBlocks(SmallPtrSetImpl<BasicBlock *> &ReachableBBs,
372 SetVector<BasicBlock *> &Worklist,
373 const SetVector<BasicBlock *> *StopPoints) {
374 while (!Worklist.empty()) {
375 BasicBlock *BB = Worklist.pop_back_val();
376
377 // Don't cross blocks that we should stop at.
378 if (StopPoints && StopPoints->count(BB))
379 continue;
380
381 if (!ReachableBBs.insert(BB).second)
382 continue; // Already visited.
383
384 // Don't follow unwind edges of invokes.
385 if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
386 Worklist.insert(II->getNormalDest());
387 continue;
388 }
389
390 // Otherwise, follow all successors.
391 Worklist.insert(succ_begin(BB), succ_end(BB));
392 }
393}
394
395/// Find all points where exceptional control rejoins normal control flow via
396/// llvm.eh.endcatch. Add them to the normal bb reachability worklist.
397static void findCXXEHReturnPoints(Function &F,
398 SetVector<BasicBlock *> &EHReturnBlocks) {
399 for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
400 BasicBlock *BB = BBI;
401 for (Instruction &I : *BB) {
402 if (match(&I, m_Intrinsic<Intrinsic::eh_endcatch>())) {
403 // Split the block after the call to llvm.eh.endcatch if there is
404 // anything other than an unconditional branch, or if the successor
405 // starts with a phi.
406 auto *Br = dyn_cast<BranchInst>(I.getNextNode());
407 if (!Br || !Br->isUnconditional() ||
408 isa<PHINode>(Br->getSuccessor(0)->begin())) {
409 DEBUG(dbgs() << "splitting block " << BB->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "splitting block " <<
BB->getName() << " with llvm.eh.endcatch\n"; } } while
(0)
410 << " with llvm.eh.endcatch\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "splitting block " <<
BB->getName() << " with llvm.eh.endcatch\n"; } } while
(0);
411 BBI = BB->splitBasicBlock(I.getNextNode(), "ehreturn");
412 }
413 // The next BB is normal control flow.
414 EHReturnBlocks.insert(BB->getTerminator()->getSuccessor(0));
415 break;
416 }
417 }
418 }
419}
420
421static bool isCatchAllLandingPad(const BasicBlock *BB) {
422 const LandingPadInst *LP = BB->getLandingPadInst();
423 if (!LP)
424 return false;
425 unsigned N = LP->getNumClauses();
426 return (N > 0 && LP->isCatch(N - 1) &&
427 isa<ConstantPointerNull>(LP->getClause(N - 1)));
428}
429
430/// Find all points where exceptions control rejoins normal control flow via
431/// selector dispatch.
432static void findSEHEHReturnPoints(Function &F,
433 SetVector<BasicBlock *> &EHReturnBlocks) {
434 for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
435 BasicBlock *BB = BBI;
436 // If the landingpad is a catch-all, treat the whole lpad as if it is
437 // reachable from normal control flow.
438 // FIXME: This is imprecise. We need a better way of identifying where a
439 // catch-all starts and cleanups stop. As far as LLVM is concerned, there
440 // is no difference.
441 if (isCatchAllLandingPad(BB)) {
442 EHReturnBlocks.insert(BB);
443 continue;
444 }
445
446 BasicBlock *CatchHandler;
447 BasicBlock *NextBB;
448 Constant *Selector;
449 if (isSelectorDispatch(BB, CatchHandler, Selector, NextBB)) {
450 // Split the edge if there is a phi node. Returning from EH to a phi node
451 // is just as impossible as having a phi after an indirectbr.
452 if (isa<PHINode>(CatchHandler->begin())) {
453 DEBUG(dbgs() << "splitting EH return edge from " << BB->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "splitting EH return edge from "
<< BB->getName() << " to " << CatchHandler
->getName() << '\n'; } } while (0)
454 << " to " << CatchHandler->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "splitting EH return edge from "
<< BB->getName() << " to " << CatchHandler
->getName() << '\n'; } } while (0);
455 BBI = CatchHandler = SplitCriticalEdge(
456 BB, std::find(succ_begin(BB), succ_end(BB), CatchHandler));
457 }
458 EHReturnBlocks.insert(CatchHandler);
459 }
460 }
461}
462
463/// Ensure that all values live into and out of exception handlers are stored
464/// in memory.
465/// FIXME: This falls down when values are defined in one handler and live into
466/// another handler. For example, a cleanup defines a value used only by a
467/// catch handler.
468void WinEHPrepare::demoteValuesLiveAcrossHandlers(
469 Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
470 DEBUG(dbgs() << "Demoting values live across exception handlers in function "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoting values live across exception handlers in function "
<< F.getName() << '\n'; } } while (0)
471 << F.getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoting values live across exception handlers in function "
<< F.getName() << '\n'; } } while (0);
472
473 // Build a set of all non-exceptional blocks and exceptional blocks.
474 // - Non-exceptional blocks are blocks reachable from the entry block while
475 // not following invoke unwind edges.
476 // - Exceptional blocks are blocks reachable from landingpads. Analysis does
477 // not follow llvm.eh.endcatch blocks, which mark a transition from
478 // exceptional to normal control.
479 SmallPtrSet<BasicBlock *, 4> NormalBlocks;
480 SmallPtrSet<BasicBlock *, 4> EHBlocks;
481 SetVector<BasicBlock *> EHReturnBlocks;
482 SetVector<BasicBlock *> Worklist;
483
484 if (Personality == EHPersonality::MSVC_CXX)
485 findCXXEHReturnPoints(F, EHReturnBlocks);
486 else
487 findSEHEHReturnPoints(F, EHReturnBlocks);
488
489 DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "identified the following blocks as EH return points:\n"
; for (BasicBlock *BB : EHReturnBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
490 dbgs() << "identified the following blocks as EH return points:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "identified the following blocks as EH return points:\n"
; for (BasicBlock *BB : EHReturnBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
491 for (BasicBlock *BB : EHReturnBlocks)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "identified the following blocks as EH return points:\n"
; for (BasicBlock *BB : EHReturnBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
492 dbgs() << " " << BB->getName() << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "identified the following blocks as EH return points:\n"
; for (BasicBlock *BB : EHReturnBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
493 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "identified the following blocks as EH return points:\n"
; for (BasicBlock *BB : EHReturnBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0);
494
495 // Join points should not have phis at this point, unless they are a
496 // landingpad, in which case we will demote their phis later.
497#ifndef NDEBUG
498 for (BasicBlock *BB : EHReturnBlocks)
499 assert((BB->isLandingPad() || !isa<PHINode>(BB->begin())) &&(((BB->isLandingPad() || !isa<PHINode>(BB->begin(
))) && "non-lpad EH return block has phi") ? static_cast
<void> (0) : __assert_fail ("(BB->isLandingPad() || !isa<PHINode>(BB->begin())) && \"non-lpad EH return block has phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 500, __PRETTY_FUNCTION__))
500 "non-lpad EH return block has phi")(((BB->isLandingPad() || !isa<PHINode>(BB->begin(
))) && "non-lpad EH return block has phi") ? static_cast
<void> (0) : __assert_fail ("(BB->isLandingPad() || !isa<PHINode>(BB->begin())) && \"non-lpad EH return block has phi\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 500, __PRETTY_FUNCTION__));
501#endif
502
503 // Normal blocks are the blocks reachable from the entry block and all EH
504 // return points.
505 Worklist = EHReturnBlocks;
506 Worklist.insert(&F.getEntryBlock());
507 findReachableBlocks(NormalBlocks, Worklist, nullptr);
508 DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as normal:\n"
; for (BasicBlock *BB : NormalBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
509 dbgs() << "marked the following blocks as normal:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as normal:\n"
; for (BasicBlock *BB : NormalBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
510 for (BasicBlock *BB : NormalBlocks)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as normal:\n"
; for (BasicBlock *BB : NormalBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
511 dbgs() << " " << BB->getName() << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as normal:\n"
; for (BasicBlock *BB : NormalBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
512 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as normal:\n"
; for (BasicBlock *BB : NormalBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0);
513
514 // Exceptional blocks are the blocks reachable from landingpads that don't
515 // cross EH return points.
516 Worklist.clear();
517 for (auto *LPI : LPads)
518 Worklist.insert(LPI->getParent());
519 findReachableBlocks(EHBlocks, Worklist, &EHReturnBlocks);
520 DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as exceptional:\n"
; for (BasicBlock *BB : EHBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
521 dbgs() << "marked the following blocks as exceptional:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as exceptional:\n"
; for (BasicBlock *BB : EHBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
522 for (BasicBlock *BB : EHBlocks)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as exceptional:\n"
; for (BasicBlock *BB : EHBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
523 dbgs() << " " << BB->getName() << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as exceptional:\n"
; for (BasicBlock *BB : EHBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0)
524 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "marked the following blocks as exceptional:\n"
; for (BasicBlock *BB : EHBlocks) dbgs() << " " <<
BB->getName() << '\n'; }; } } while (0);
525
526 SetVector<Argument *> ArgsToDemote;
527 SetVector<Instruction *> InstrsToDemote;
528 for (BasicBlock &BB : F) {
529 bool IsNormalBB = NormalBlocks.count(&BB);
530 bool IsEHBB = EHBlocks.count(&BB);
531 if (!IsNormalBB && !IsEHBB)
532 continue; // Blocks that are neither normal nor EH are unreachable.
533 for (Instruction &I : BB) {
534 for (Value *Op : I.operands()) {
535 // Don't demote static allocas, constants, and labels.
536 if (isa<Constant>(Op) || isa<BasicBlock>(Op) || isa<InlineAsm>(Op))
537 continue;
538 auto *AI = dyn_cast<AllocaInst>(Op);
539 if (AI && AI->isStaticAlloca())
540 continue;
541
542 if (auto *Arg = dyn_cast<Argument>(Op)) {
543 if (IsEHBB) {
544 DEBUG(dbgs() << "Demoting argument " << *Argdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoting argument " <<
*Arg << " used by EH instr: " << I << "\n"
; } } while (0)
545 << " used by EH instr: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoting argument " <<
*Arg << " used by EH instr: " << I << "\n"
; } } while (0);
546 ArgsToDemote.insert(Arg);
547 }
548 continue;
549 }
550
551 auto *OpI = cast<Instruction>(Op);
552 BasicBlock *OpBB = OpI->getParent();
553 // If a value is produced and consumed in the same BB, we don't need to
554 // demote it.
555 if (OpBB == &BB)
556 continue;
557 bool IsOpNormalBB = NormalBlocks.count(OpBB);
558 bool IsOpEHBB = EHBlocks.count(OpBB);
559 if (IsNormalBB != IsOpNormalBB || IsEHBB != IsOpEHBB) {
560 DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "Demoting instruction live in-out from EH:\n"
; dbgs() << "Instr: " << *OpI << '\n'; dbgs
() << "User: " << I << '\n'; }; } } while (
0)
561 dbgs() << "Demoting instruction live in-out from EH:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "Demoting instruction live in-out from EH:\n"
; dbgs() << "Instr: " << *OpI << '\n'; dbgs
() << "User: " << I << '\n'; }; } } while (
0)
562 dbgs() << "Instr: " << *OpI << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "Demoting instruction live in-out from EH:\n"
; dbgs() << "Instr: " << *OpI << '\n'; dbgs
() << "User: " << I << '\n'; }; } } while (
0)
563 dbgs() << "User: " << I << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "Demoting instruction live in-out from EH:\n"
; dbgs() << "Instr: " << *OpI << '\n'; dbgs
() << "User: " << I << '\n'; }; } } while (
0)
564 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { { dbgs() << "Demoting instruction live in-out from EH:\n"
; dbgs() << "Instr: " << *OpI << '\n'; dbgs
() << "User: " << I << '\n'; }; } } while (
0);
565 InstrsToDemote.insert(OpI);
566 }
567 }
568 }
569 }
570
571 // Demote values live into and out of handlers.
572 // FIXME: This demotion is inefficient. We should insert spills at the point
573 // of definition, insert one reload in each handler that uses the value, and
574 // insert reloads in the BB used to rejoin normal control flow.
575 Instruction *AllocaInsertPt = F.getEntryBlock().getFirstInsertionPt();
576 for (Instruction *I : InstrsToDemote)
577 DemoteRegToStack(*I, false, AllocaInsertPt);
578
579 // Demote arguments separately, and only for uses in EH blocks.
580 for (Argument *Arg : ArgsToDemote) {
581 auto *Slot = new AllocaInst(Arg->getType(), nullptr,
582 Arg->getName() + ".reg2mem", AllocaInsertPt);
583 SmallVector<User *, 4> Users(Arg->user_begin(), Arg->user_end());
584 for (User *U : Users) {
585 auto *I = dyn_cast<Instruction>(U);
586 if (I && EHBlocks.count(I->getParent())) {
587 auto *Reload = new LoadInst(Slot, Arg->getName() + ".reload", false, I);
588 U->replaceUsesOfWith(Arg, Reload);
589 }
590 }
591 new StoreInst(Arg, Slot, AllocaInsertPt);
592 }
593
594 // Demote landingpad phis, as the landingpad will be removed from the machine
595 // CFG.
596 for (LandingPadInst *LPI : LPads) {
597 BasicBlock *BB = LPI->getParent();
598 while (auto *Phi = dyn_cast<PHINode>(BB->begin()))
599 DemotePHIToStack(Phi, AllocaInsertPt);
600 }
601
602 DEBUG(dbgs() << "Demoted " << InstrsToDemote.size() << " instructions and "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoted " << InstrsToDemote
.size() << " instructions and " << ArgsToDemote.size
() << " arguments for WinEHPrepare\n\n"; } } while (0)
603 << ArgsToDemote.size() << " arguments for WinEHPrepare\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Demoted " << InstrsToDemote
.size() << " instructions and " << ArgsToDemote.size
() << " arguments for WinEHPrepare\n\n"; } } while (0);
604}
605
606bool WinEHPrepare::prepareExceptionHandlers(
607 Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
608 // Don't run on functions that are already prepared.
609 for (LandingPadInst *LPad : LPads) {
610 BasicBlock *LPadBB = LPad->getParent();
611 for (Instruction &Inst : *LPadBB)
612 if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>()))
613 return false;
614 }
615
616 demoteValuesLiveAcrossHandlers(F, LPads);
617
618 // These containers are used to re-map frame variables that are used in
619 // outlined catch and cleanup handlers. They will be populated as the
620 // handlers are outlined.
621 FrameVarInfoMap FrameVarInfo;
622
623 bool HandlersOutlined = false;
624
625 Module *M = F.getParent();
626 LLVMContext &Context = M->getContext();
627
628 // Create a new function to receive the handler contents.
629 PointerType *Int8PtrType = Type::getInt8PtrTy(Context);
630 Type *Int32Type = Type::getInt32Ty(Context);
631 Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions);
632
633 if (isAsynchronousEHPersonality(Personality)) {
634 // FIXME: Switch the ehptr type to i32 and then switch this.
635 SEHExceptionCodeSlot =
636 new AllocaInst(Int8PtrType, nullptr, "seh_exception_code",
637 F.getEntryBlock().getFirstInsertionPt());
638 }
639
640 for (LandingPadInst *LPad : LPads) {
641 // Look for evidence that this landingpad has already been processed.
642 bool LPadHasActionList = false;
643 BasicBlock *LPadBB = LPad->getParent();
644 for (Instruction &Inst : *LPadBB) {
645 if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>())) {
646 LPadHasActionList = true;
647 break;
648 }
649 }
650
651 // If we've already outlined the handlers for this landingpad,
652 // there's nothing more to do here.
653 if (LPadHasActionList)
654 continue;
655
656 // If either of the values in the aggregate returned by the landing pad is
657 // extracted and stored to memory, promote the stored value to a register.
658 promoteLandingPadValues(LPad);
659
660 LandingPadActions Actions;
661 mapLandingPadBlocks(LPad, Actions);
662
663 HandlersOutlined |= !Actions.actions().empty();
664 for (ActionHandler *Action : Actions) {
665 if (Action->hasBeenProcessed())
666 continue;
667 BasicBlock *StartBB = Action->getStartBlock();
668
669 // SEH doesn't do any outlining for catches. Instead, pass the handler
670 // basic block addr to llvm.eh.actions and list the block as a return
671 // target.
672 if (isAsynchronousEHPersonality(Personality)) {
673 if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
674 processSEHCatchHandler(CatchAction, StartBB);
675 continue;
676 }
677 }
678
679 outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo);
680 }
681
682 // Split the block after the landingpad instruction so that it is just a
683 // call to llvm.eh.actions followed by indirectbr.
684 assert(!isa<PHINode>(LPadBB->begin()) && "lpad phi not removed")((!isa<PHINode>(LPadBB->begin()) && "lpad phi not removed"
) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(LPadBB->begin()) && \"lpad phi not removed\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 684, __PRETTY_FUNCTION__));
685 LPadBB->splitBasicBlock(LPad->getNextNode(),
686 LPadBB->getName() + ".prepsplit");
687 // Erase the branch inserted by the split so we can insert indirectbr.
688 LPadBB->getTerminator()->eraseFromParent();
689
690 // Replace all extracted values with undef and ultimately replace the
691 // landingpad with undef.
692 SmallVector<Instruction *, 4> SEHCodeUses;
693 SmallVector<Instruction *, 4> EHUndefs;
694 for (User *U : LPad->users()) {
695 auto *E = dyn_cast<ExtractValueInst>(U);
696 if (!E)
697 continue;
698 assert(E->getNumIndices() == 1 &&((E->getNumIndices() == 1 && "Unexpected operation: extracting both landing pad values"
) ? static_cast<void> (0) : __assert_fail ("E->getNumIndices() == 1 && \"Unexpected operation: extracting both landing pad values\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 699, __PRETTY_FUNCTION__))
699 "Unexpected operation: extracting both landing pad values")((E->getNumIndices() == 1 && "Unexpected operation: extracting both landing pad values"
) ? static_cast<void> (0) : __assert_fail ("E->getNumIndices() == 1 && \"Unexpected operation: extracting both landing pad values\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 699, __PRETTY_FUNCTION__));
700 unsigned Idx = *E->idx_begin();
701 assert((Idx == 0 || Idx == 1) && "unexpected index")(((Idx == 0 || Idx == 1) && "unexpected index") ? static_cast
<void> (0) : __assert_fail ("(Idx == 0 || Idx == 1) && \"unexpected index\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 701, __PRETTY_FUNCTION__));
702 if (Idx == 0 && isAsynchronousEHPersonality(Personality))
703 SEHCodeUses.push_back(E);
704 else
705 EHUndefs.push_back(E);
706 }
707 for (Instruction *E : EHUndefs) {
708 E->replaceAllUsesWith(UndefValue::get(E->getType()));
709 E->eraseFromParent();
710 }
711 LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
712
713 // Rewrite uses of the exception pointer to loads of an alloca.
714 for (Instruction *E : SEHCodeUses) {
715 SmallVector<Use *, 4> Uses;
716 for (Use &U : E->uses())
717 Uses.push_back(&U);
718 for (Use *U : Uses) {
719 auto *I = cast<Instruction>(U->getUser());
720 if (isa<ResumeInst>(I))
721 continue;
722 LoadInst *LI;
723 if (auto *Phi = dyn_cast<PHINode>(I))
724 LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false,
725 Phi->getIncomingBlock(*U));
726 else
727 LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I);
728 U->set(LI);
729 }
730 E->replaceAllUsesWith(UndefValue::get(E->getType()));
731 E->eraseFromParent();
732 }
733
734 // Add a call to describe the actions for this landing pad.
735 std::vector<Value *> ActionArgs;
736 for (ActionHandler *Action : Actions) {
737 // Action codes from docs are: 0 cleanup, 1 catch.
738 if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
739 ActionArgs.push_back(ConstantInt::get(Int32Type, 1));
740 ActionArgs.push_back(CatchAction->getSelector());
741 // Find the frame escape index of the exception object alloca in the
742 // parent.
743 int FrameEscapeIdx = -1;
744 Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar());
745 if (EHObj && !isa<ConstantPointerNull>(EHObj)) {
746 auto I = FrameVarInfo.find(EHObj);
747 assert(I != FrameVarInfo.end() &&((I != FrameVarInfo.end() && "failed to map llvm.eh.begincatch var"
) ? static_cast<void> (0) : __assert_fail ("I != FrameVarInfo.end() && \"failed to map llvm.eh.begincatch var\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 748, __PRETTY_FUNCTION__))
748 "failed to map llvm.eh.begincatch var")((I != FrameVarInfo.end() && "failed to map llvm.eh.begincatch var"
) ? static_cast<void> (0) : __assert_fail ("I != FrameVarInfo.end() && \"failed to map llvm.eh.begincatch var\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 748, __PRETTY_FUNCTION__));
749 FrameEscapeIdx = std::distance(FrameVarInfo.begin(), I);
750 }
751 ActionArgs.push_back(ConstantInt::get(Int32Type, FrameEscapeIdx));
752 } else {
753 ActionArgs.push_back(ConstantInt::get(Int32Type, 0));
754 }
755 ActionArgs.push_back(Action->getHandlerBlockOrFunc());
756 }
757 CallInst *Recover =
758 CallInst::Create(ActionIntrin, ActionArgs, "recover", LPadBB);
759
760 // Add an indirect branch listing possible successors of the catch handlers.
761 SetVector<BasicBlock *> ReturnTargets;
762 for (ActionHandler *Action : Actions) {
763 if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
764 const auto &CatchTargets = CatchAction->getReturnTargets();
765 ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end());
766 }
767 }
768 IndirectBrInst *Branch =
769 IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB);
770 for (BasicBlock *Target : ReturnTargets)
771 Branch->addDestination(Target);
772 } // End for each landingpad
773
774 // If nothing got outlined, there is no more processing to be done.
775 if (!HandlersOutlined)
776 return false;
777
778 // Replace any nested landing pad stubs with the correct action handler.
779 // This must be done before we remove unreachable blocks because it
780 // cleans up references to outlined blocks that will be deleted.
781 for (auto &LPadPair : NestedLPtoOriginalLP)
782 completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo);
783 NestedLPtoOriginalLP.clear();
784
785 F.addFnAttr("wineh-parent", F.getName());
786
787 // Delete any blocks that were only used by handlers that were outlined above.
788 removeUnreachableBlocks(F);
789
790 BasicBlock *Entry = &F.getEntryBlock();
791 IRBuilder<> Builder(F.getParent()->getContext());
792 Builder.SetInsertPoint(Entry->getFirstInsertionPt());
793
794 Function *FrameEscapeFn =
795 Intrinsic::getDeclaration(M, Intrinsic::frameescape);
796 Function *RecoverFrameFn =
797 Intrinsic::getDeclaration(M, Intrinsic::framerecover);
798 SmallVector<Value *, 8> AllocasToEscape;
799
800 // Scan the entry block for an existing call to llvm.frameescape. We need to
801 // keep escaping those objects.
802 for (Instruction &I : F.front()) {
803 auto *II = dyn_cast<IntrinsicInst>(&I);
804 if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
805 auto Args = II->arg_operands();
806 AllocasToEscape.append(Args.begin(), Args.end());
807 II->eraseFromParent();
808 break;
809 }
810 }
811
812 // Finally, replace all of the temporary allocas for frame variables used in
813 // the outlined handlers with calls to llvm.framerecover.
814 for (auto &VarInfoEntry : FrameVarInfo) {
815 Value *ParentVal = VarInfoEntry.first;
816 TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
817 AllocaInst *ParentAlloca = cast<AllocaInst>(ParentVal);
818
819 // FIXME: We should try to sink unescaped allocas from the parent frame into
820 // the child frame. If the alloca is escaped, we have to use the lifetime
821 // markers to ensure that the alloca is only live within the child frame.
822
823 // Add this alloca to the list of things to escape.
824 AllocasToEscape.push_back(ParentAlloca);
825
826 // Next replace all outlined allocas that are mapped to it.
827 for (AllocaInst *TempAlloca : Allocas) {
828 if (TempAlloca == getCatchObjectSentinel())
829 continue; // Skip catch parameter sentinels.
830 Function *HandlerFn = TempAlloca->getParent()->getParent();
831 // FIXME: Sink this GEP into the blocks where it is used.
832 Builder.SetInsertPoint(TempAlloca);
833 Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
834 Value *RecoverArgs[] = {
835 Builder.CreateBitCast(&F, Int8PtrType, ""),
836 &(HandlerFn->getArgumentList().back()),
837 llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
838 Value *RecoveredAlloca = Builder.CreateCall(RecoverFrameFn, RecoverArgs);
839 // Add a pointer bitcast if the alloca wasn't an i8.
840 if (RecoveredAlloca->getType() != TempAlloca->getType()) {
841 RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8");
842 RecoveredAlloca =
843 Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType());
844 }
845 TempAlloca->replaceAllUsesWith(RecoveredAlloca);
846 TempAlloca->removeFromParent();
847 RecoveredAlloca->takeName(TempAlloca);
848 delete TempAlloca;
849 }
850 } // End for each FrameVarInfo entry.
851
852 // Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry
853 // block.
854 Builder.SetInsertPoint(&F.getEntryBlock().back());
855 Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
856
857 if (SEHExceptionCodeSlot) {
858 if (SEHExceptionCodeSlot->hasNUses(0))
859 SEHExceptionCodeSlot->eraseFromParent();
860 else
861 PromoteMemToReg(SEHExceptionCodeSlot, *DT);
862 }
863
864 // Clean up the handler action maps we created for this function
865 DeleteContainerSeconds(CatchHandlerMap);
866 CatchHandlerMap.clear();
867 DeleteContainerSeconds(CleanupHandlerMap);
868 CleanupHandlerMap.clear();
869
870 return HandlersOutlined;
871}
872
873void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) {
874 // If the return values of the landing pad instruction are extracted and
875 // stored to memory, we want to promote the store locations to reg values.
876 SmallVector<AllocaInst *, 2> EHAllocas;
877
878 // The landingpad instruction returns an aggregate value. Typically, its
879 // value will be passed to a pair of extract value instructions and the
880 // results of those extracts are often passed to store instructions.
881 // In unoptimized code the stored value will often be loaded and then stored
882 // again.
883 for (auto *U : LPad->users()) {
884 ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
885 if (!Extract)
886 continue;
887
888 for (auto *EU : Extract->users()) {
889 if (auto *Store = dyn_cast<StoreInst>(EU)) {
890 auto *AV = cast<AllocaInst>(Store->getPointerOperand());
891 EHAllocas.push_back(AV);
892 }
893 }
894 }
895
896 // We can't do this without a dominator tree.
897 assert(DT)((DT) ? static_cast<void> (0) : __assert_fail ("DT", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 897, __PRETTY_FUNCTION__));
898
899 if (!EHAllocas.empty()) {
900 PromoteMemToReg(EHAllocas, *DT);
901 EHAllocas.clear();
902 }
903
904 // After promotion, some extracts may be trivially dead. Remove them.
905 SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end());
906 for (auto *U : Users)
907 RecursivelyDeleteTriviallyDeadInstructions(U);
908}
909
910void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
911 LandingPadInst *OutlinedLPad,
912 const LandingPadInst *OriginalLPad,
913 FrameVarInfoMap &FrameVarInfo) {
914 // Get the nested block and erase the unreachable instruction that was
915 // temporarily inserted as its terminator.
916 LLVMContext &Context = ParentFn->getContext();
917 BasicBlock *OutlinedBB = OutlinedLPad->getParent();
918 assert(isa<UnreachableInst>(OutlinedBB->getTerminator()))((isa<UnreachableInst>(OutlinedBB->getTerminator()))
? static_cast<void> (0) : __assert_fail ("isa<UnreachableInst>(OutlinedBB->getTerminator())"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 918, __PRETTY_FUNCTION__));
919 OutlinedBB->getTerminator()->eraseFromParent();
920 // That should leave OutlinedLPad as the last instruction in its block.
921 assert(&OutlinedBB->back() == OutlinedLPad)((&OutlinedBB->back() == OutlinedLPad) ? static_cast<
void> (0) : __assert_fail ("&OutlinedBB->back() == OutlinedLPad"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 921, __PRETTY_FUNCTION__));
922
923 // The original landing pad will have already had its action intrinsic
924 // built by the outlining loop. We need to clone that into the outlined
925 // location. It may also be necessary to add references to the exception
926 // variables to the outlined handler in which this landing pad is nested
927 // and remap return instructions in the nested handlers that should return
928 // to an address in the outlined handler.
929 Function *OutlinedHandlerFn = OutlinedBB->getParent();
930 BasicBlock::const_iterator II = OriginalLPad;
931 ++II;
932 // The instruction after the landing pad should now be a call to eh.actions.
933 const Instruction *Recover = II;
934 assert(match(Recover, m_Intrinsic<Intrinsic::eh_actions>()))((match(Recover, m_Intrinsic<Intrinsic::eh_actions>()))
? static_cast<void> (0) : __assert_fail ("match(Recover, m_Intrinsic<Intrinsic::eh_actions>())"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 934, __PRETTY_FUNCTION__));
935 IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover->clone());
936
937 // Remap the exception variables into the outlined function.
938 WinEHFrameVariableMaterializer Materializer(OutlinedHandlerFn, FrameVarInfo);
939 SmallVector<BlockAddress *, 4> ActionTargets;
940 SmallVector<ActionHandler *, 4> ActionList;
941 parseEHActions(EHActions, ActionList);
942 for (auto *Action : ActionList) {
943 auto *Catch = dyn_cast<CatchHandler>(Action);
944 if (!Catch)
945 continue;
946 // The dyn_cast to function here selects C++ catch handlers and skips
947 // SEH catch handlers.
948 auto *Handler = dyn_cast<Function>(Catch->getHandlerBlockOrFunc());
949 if (!Handler)
950 continue;
951 // Visit all the return instructions, looking for places that return
952 // to a location within OutlinedHandlerFn.
953 for (BasicBlock &NestedHandlerBB : *Handler) {
954 auto *Ret = dyn_cast<ReturnInst>(NestedHandlerBB.getTerminator());
955 if (!Ret)
956 continue;
957
958 // Handler functions must always return a block address.
959 BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
960 // The original target will have been in the main parent function,
961 // but if it is the address of a block that has been outlined, it
962 // should be a block that was outlined into OutlinedHandlerFn.
963 assert(BA->getFunction() == ParentFn)((BA->getFunction() == ParentFn) ? static_cast<void>
(0) : __assert_fail ("BA->getFunction() == ParentFn", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 963, __PRETTY_FUNCTION__));
964
965 // Ignore targets that aren't part of OutlinedHandlerFn.
966 if (!LPadTargetBlocks.count(BA->getBasicBlock()))
967 continue;
968
969 // If the return value is the address ofF a block that we
970 // previously outlined into the parent handler function, replace
971 // the return instruction and add the mapped target to the list
972 // of possible return addresses.
973 BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()];
974 assert(MappedBB->getParent() == OutlinedHandlerFn)((MappedBB->getParent() == OutlinedHandlerFn) ? static_cast
<void> (0) : __assert_fail ("MappedBB->getParent() == OutlinedHandlerFn"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 974, __PRETTY_FUNCTION__));
975 BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB);
976 Ret->eraseFromParent();
977 ReturnInst::Create(Context, NewBA, &NestedHandlerBB);
978 ActionTargets.push_back(NewBA);
979 }
980 }
981 DeleteContainerPointers(ActionList);
982 ActionList.clear();
983 OutlinedBB->getInstList().push_back(EHActions);
984
985 // Insert an indirect branch into the outlined landing pad BB.
986 IndirectBrInst *IBr = IndirectBrInst::Create(EHActions, 0, OutlinedBB);
987 // Add the previously collected action targets.
988 for (auto *Target : ActionTargets)
989 IBr->addDestination(Target->getBasicBlock());
990}
991
992// This function examines a block to determine whether the block ends with a
993// conditional branch to a catch handler based on a selector comparison.
994// This function is used both by the WinEHPrepare::findSelectorComparison() and
995// WinEHCleanupDirector::handleTypeIdFor().
996static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
997 Constant *&Selector, BasicBlock *&NextBB) {
998 ICmpInst::Predicate Pred;
999 BasicBlock *TBB, *FBB;
1000 Value *LHS, *RHS;
1001
1002 if (!match(BB->getTerminator(),
1003 m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)), TBB, FBB)))
1004 return false;
1005
1006 if (!match(LHS,
1007 m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))) &&
1008 !match(RHS, m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))))
1009 return false;
1010
1011 if (Pred == CmpInst::ICMP_EQ) {
1012 CatchHandler = TBB;
1013 NextBB = FBB;
1014 return true;
1015 }
1016
1017 if (Pred == CmpInst::ICMP_NE) {
1018 CatchHandler = FBB;
1019 NextBB = TBB;
1020 return true;
1021 }
1022
1023 return false;
1024}
1025
1026static bool isCatchBlock(BasicBlock *BB) {
1027 for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
1028 II != IE; ++II) {
1029 if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_begincatch>()))
1030 return true;
1031 }
1032 return false;
1033}
1034
1035static BasicBlock *createStubLandingPad(Function *Handler,
1036 Value *PersonalityFn) {
1037 // FIXME: Finish this!
1038 LLVMContext &Context = Handler->getContext();
1039 BasicBlock *StubBB = BasicBlock::Create(Context, "stub");
1040 Handler->getBasicBlockList().push_back(StubBB);
1041 IRBuilder<> Builder(StubBB);
1042 LandingPadInst *LPad = Builder.CreateLandingPad(
1043 llvm::StructType::get(Type::getInt8PtrTy(Context),
1044 Type::getInt32Ty(Context), nullptr),
1045 PersonalityFn, 0);
1046 // Insert a call to llvm.eh.actions so that we don't try to outline this lpad.
1047 Function *ActionIntrin = Intrinsic::getDeclaration(Handler->getParent(),
1048 Intrinsic::eh_actions);
1049 Builder.CreateCall(ActionIntrin, "recover");
1050 LPad->setCleanup(true);
1051 Builder.CreateUnreachable();
1052 return StubBB;
1053}
1054
1055// Cycles through the blocks in an outlined handler function looking for an
1056// invoke instruction and inserts an invoke of llvm.donothing with an empty
1057// landing pad if none is found. The code that generates the .xdata tables for
1058// the handler needs at least one landing pad to identify the parent function's
1059// personality.
1060void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler,
1061 Value *PersonalityFn) {
1062 ReturnInst *Ret = nullptr;
1063 UnreachableInst *Unreached = nullptr;
1064 for (BasicBlock &BB : *Handler) {
1065 TerminatorInst *Terminator = BB.getTerminator();
1066 // If we find an invoke, there is nothing to be done.
1067 auto *II = dyn_cast<InvokeInst>(Terminator);
1068 if (II)
1069 return;
1070 // If we've already recorded a return instruction, keep looking for invokes.
1071 if (!Ret)
1072 Ret = dyn_cast<ReturnInst>(Terminator);
1073 // If we haven't recorded an unreachable instruction, try this terminator.
1074 if (!Unreached)
1075 Unreached = dyn_cast<UnreachableInst>(Terminator);
1076 }
1077
1078 // If we got this far, the handler contains no invokes. We should have seen
1079 // at least one return or unreachable instruction. We'll insert an invoke of
1080 // llvm.donothing ahead of that instruction.
1081 assert(Ret || Unreached)((Ret || Unreached) ? static_cast<void> (0) : __assert_fail
("Ret || Unreached", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1081, __PRETTY_FUNCTION__));
1082 TerminatorInst *Term;
1083 if (Ret)
1084 Term = Ret;
1085 else
1086 Term = Unreached;
1087 BasicBlock *OldRetBB = Term->getParent();
1088 BasicBlock *NewRetBB = SplitBlock(OldRetBB, Term);
1089 // SplitBlock adds an unconditional branch instruction at the end of the
1090 // parent block. We want to replace that with an invoke call, so we can
1091 // erase it now.
1092 OldRetBB->getTerminator()->eraseFromParent();
1093 BasicBlock *StubLandingPad = createStubLandingPad(Handler, PersonalityFn);
1094 Function *F =
1095 Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing);
1096 InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB);
1097}
1098
1099bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
1100 LandingPadInst *LPad, BasicBlock *StartBB,
1101 FrameVarInfoMap &VarInfo) {
1102 Module *M = SrcFn->getParent();
1103 LLVMContext &Context = M->getContext();
1104
1105 // Create a new function to receive the handler contents.
1106 Type *Int8PtrType = Type::getInt8PtrTy(Context);
1107 std::vector<Type *> ArgTys;
1108 ArgTys.push_back(Int8PtrType);
1109 ArgTys.push_back(Int8PtrType);
1110 Function *Handler;
1111 if (Action->getType() == Catch) {
1112 FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
1113 Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
1114 SrcFn->getName() + ".catch", M);
1115 } else {
1116 FunctionType *FnType =
1117 FunctionType::get(Type::getVoidTy(Context), ArgTys, false);
1118 Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
1119 SrcFn->getName() + ".cleanup", M);
1120 }
1121
1122 Handler->addFnAttr("wineh-parent", SrcFn->getName());
1123
1124 // Generate a standard prolog to setup the frame recovery structure.
1125 IRBuilder<> Builder(Context);
1126 BasicBlock *Entry = BasicBlock::Create(Context, "entry");
1127 Handler->getBasicBlockList().push_front(Entry);
1128 Builder.SetInsertPoint(Entry);
1129 Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
1130
1131 std::unique_ptr<WinEHCloningDirectorBase> Director;
1132
1133 ValueToValueMapTy VMap;
1134
1135 LandingPadMap &LPadMap = LPadMaps[LPad];
1136 if (!LPadMap.isInitialized())
1137 LPadMap.mapLandingPad(LPad);
1138 if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
1139 Constant *Sel = CatchAction->getSelector();
1140 Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap,
1141 NestedLPtoOriginalLP));
1142 LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
1143 ConstantInt::get(Type::getInt32Ty(Context), 1));
1144 } else {
1145 Director.reset(new WinEHCleanupDirector(Handler, VarInfo, LPadMap));
1146 LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
1147 UndefValue::get(Type::getInt32Ty(Context)));
1148 }
1149
1150 SmallVector<ReturnInst *, 8> Returns;
1151 ClonedCodeInfo OutlinedFunctionInfo;
1152
1153 // If the start block contains PHI nodes, we need to map them.
1154 BasicBlock::iterator II = StartBB->begin();
1155 while (auto *PN = dyn_cast<PHINode>(II)) {
1156 bool Mapped = false;
1157 // Look for PHI values that we have already mapped (such as the selector).
1158 for (Value *Val : PN->incoming_values()) {
1159 if (VMap.count(Val)) {
1160 VMap[PN] = VMap[Val];
1161 Mapped = true;
1162 }
1163 }
1164 // If we didn't find a match for this value, map it as an undef.
1165 if (!Mapped) {
1166 VMap[PN] = UndefValue::get(PN->getType());
1167 }
1168 ++II;
1169 }
1170
1171 // The landing pad value may be used by PHI nodes. It will ultimately be
1172 // eliminated, but we need it in the map for intermediate handling.
1173 VMap[LPad] = UndefValue::get(LPad->getType());
1174
1175 // Skip over PHIs and, if applicable, landingpad instructions.
1176 II = StartBB->getFirstInsertionPt();
1177
1178 CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap,
1179 /*ModuleLevelChanges=*/false, Returns, "",
1180 &OutlinedFunctionInfo, Director.get());
1181
1182 // Move all the instructions in the cloned "entry" block into our entry block.
1183 // Depending on how the parent function was laid out, the block that will
1184 // correspond to the outlined entry block may not be the first block in the
1185 // list. We can recognize it, however, as the cloned block which has no
1186 // predecessors. Any other block wouldn't have been cloned if it didn't
1187 // have a predecessor which was also cloned.
1188 Function::iterator ClonedIt = std::next(Function::iterator(Entry));
1189 while (!pred_empty(ClonedIt))
1190 ++ClonedIt;
1191 BasicBlock *ClonedEntryBB = ClonedIt;
1192 assert(ClonedEntryBB)((ClonedEntryBB) ? static_cast<void> (0) : __assert_fail
("ClonedEntryBB", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1192, __PRETTY_FUNCTION__));
1193 Entry->getInstList().splice(Entry->end(), ClonedEntryBB->getInstList());
1194 ClonedEntryBB->eraseFromParent();
1195
1196 // Make sure we can identify the handler's personality later.
1197 addStubInvokeToHandlerIfNeeded(Handler, LPad->getPersonalityFn());
1198
1199 if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
1200 WinEHCatchDirector *CatchDirector =
1201 reinterpret_cast<WinEHCatchDirector *>(Director.get());
1202 CatchAction->setExceptionVar(CatchDirector->getExceptionVar());
1203 CatchAction->setReturnTargets(CatchDirector->getReturnTargets());
1204
1205 // Look for blocks that are not part of the landing pad that we just
1206 // outlined but terminate with a call to llvm.eh.endcatch and a
1207 // branch to a block that is in the handler we just outlined.
1208 // These blocks will be part of a nested landing pad that intends to
1209 // return to an address in this handler. This case is best handled
1210 // after both landing pads have been outlined, so for now we'll just
1211 // save the association of the blocks in LPadTargetBlocks. The
1212 // return instructions which are created from these branches will be
1213 // replaced after all landing pads have been outlined.
1214 for (const auto MapEntry : VMap) {
1215 // VMap maps all values and blocks that were just cloned, but dead
1216 // blocks which were pruned will map to nullptr.
1217 if (!isa<BasicBlock>(MapEntry.first) || MapEntry.second == nullptr)
1218 continue;
1219 const BasicBlock *MappedBB = cast<BasicBlock>(MapEntry.first);
1220 for (auto *Pred : predecessors(const_cast<BasicBlock *>(MappedBB))) {
1221 auto *Branch = dyn_cast<BranchInst>(Pred->getTerminator());
1222 if (!Branch || !Branch->isUnconditional() || Pred->size() <= 1)
1223 continue;
1224 BasicBlock::iterator II = const_cast<BranchInst *>(Branch);
1225 --II;
1226 if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_endcatch>())) {
1227 // This would indicate that a nested landing pad wants to return
1228 // to a block that is outlined into two different handlers.
1229 assert(!LPadTargetBlocks.count(MappedBB))((!LPadTargetBlocks.count(MappedBB)) ? static_cast<void>
(0) : __assert_fail ("!LPadTargetBlocks.count(MappedBB)", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1229, __PRETTY_FUNCTION__));
1230 LPadTargetBlocks[MappedBB] = cast<BasicBlock>(MapEntry.second);
1231 }
1232 }
1233 }
1234 } // End if (CatchAction)
1235
1236 Action->setHandlerBlockOrFunc(Handler);
1237
1238 return true;
1239}
1240
1241/// This BB must end in a selector dispatch. All we need to do is pass the
1242/// handler block to llvm.eh.actions and list it as a possible indirectbr
1243/// target.
1244void WinEHPrepare::processSEHCatchHandler(CatchHandler *CatchAction,
1245 BasicBlock *StartBB) {
1246 BasicBlock *HandlerBB;
1247 BasicBlock *NextBB;
1248 Constant *Selector;
1249 bool Res = isSelectorDispatch(StartBB, HandlerBB, Selector, NextBB);
1250 if (Res) {
1251 // If this was EH dispatch, this must be a conditional branch to the handler
1252 // block.
1253 // FIXME: Handle instructions in the dispatch block. Currently we drop them,
1254 // leading to crashes if some optimization hoists stuff here.
1255 assert(CatchAction->getSelector() && HandlerBB &&((CatchAction->getSelector() && HandlerBB &&
"expected catch EH dispatch") ? static_cast<void> (0) :
__assert_fail ("CatchAction->getSelector() && HandlerBB && \"expected catch EH dispatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1256, __PRETTY_FUNCTION__))
1256 "expected catch EH dispatch")((CatchAction->getSelector() && HandlerBB &&
"expected catch EH dispatch") ? static_cast<void> (0) :
__assert_fail ("CatchAction->getSelector() && HandlerBB && \"expected catch EH dispatch\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1256, __PRETTY_FUNCTION__));
1257 } else {
1258 // This must be a catch-all. Split the block after the landingpad.
1259 assert(CatchAction->getSelector()->isNullValue() && "expected catch-all")((CatchAction->getSelector()->isNullValue() && "expected catch-all"
) ? static_cast<void> (0) : __assert_fail ("CatchAction->getSelector()->isNullValue() && \"expected catch-all\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1259, __PRETTY_FUNCTION__));
1260 HandlerBB =
1261 StartBB->splitBasicBlock(StartBB->getFirstInsertionPt(), "catch.all");
1262 }
1263 IRBuilder<> Builder(HandlerBB->getFirstInsertionPt());
1264 Function *EHCodeFn = Intrinsic::getDeclaration(
1265 StartBB->getParent()->getParent(), Intrinsic::eh_exceptioncode);
1266 Value *Code = Builder.CreateCall(EHCodeFn, "sehcode");
1267 Code = Builder.CreateIntToPtr(Code, SEHExceptionCodeSlot->getAllocatedType());
1268 Builder.CreateStore(Code, SEHExceptionCodeSlot);
1269 CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB));
1270 TinyPtrVector<BasicBlock *> Targets(HandlerBB);
1271 CatchAction->setReturnTargets(Targets);
1272}
1273
1274void LandingPadMap::mapLandingPad(const LandingPadInst *LPad) {
1275 // Each instance of this class should only ever be used to map a single
1276 // landing pad.
1277 assert(OriginLPad == nullptr || OriginLPad == LPad)((OriginLPad == nullptr || OriginLPad == LPad) ? static_cast<
void> (0) : __assert_fail ("OriginLPad == nullptr || OriginLPad == LPad"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1277, __PRETTY_FUNCTION__));
1278
1279 // If the landing pad has already been mapped, there's nothing more to do.
1280 if (OriginLPad == LPad)
1281 return;
1282
1283 OriginLPad = LPad;
1284
1285 // The landingpad instruction returns an aggregate value. Typically, its
1286 // value will be passed to a pair of extract value instructions and the
1287 // results of those extracts will have been promoted to reg values before
1288 // this routine is called.
1289 for (auto *U : LPad->users()) {
1290 const ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
1291 if (!Extract)
1292 continue;
1293 assert(Extract->getNumIndices() == 1 &&((Extract->getNumIndices() == 1 && "Unexpected operation: extracting both landing pad values"
) ? static_cast<void> (0) : __assert_fail ("Extract->getNumIndices() == 1 && \"Unexpected operation: extracting both landing pad values\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1294, __PRETTY_FUNCTION__))
1294 "Unexpected operation: extracting both landing pad values")((Extract->getNumIndices() == 1 && "Unexpected operation: extracting both landing pad values"
) ? static_cast<void> (0) : __assert_fail ("Extract->getNumIndices() == 1 && \"Unexpected operation: extracting both landing pad values\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1294, __PRETTY_FUNCTION__));
1295 unsigned int Idx = *(Extract->idx_begin());
1296 assert((Idx == 0 || Idx == 1) &&(((Idx == 0 || Idx == 1) && "Unexpected operation: extracting an unknown landing pad element"
) ? static_cast<void> (0) : __assert_fail ("(Idx == 0 || Idx == 1) && \"Unexpected operation: extracting an unknown landing pad element\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1297, __PRETTY_FUNCTION__))
1297 "Unexpected operation: extracting an unknown landing pad element")(((Idx == 0 || Idx == 1) && "Unexpected operation: extracting an unknown landing pad element"
) ? static_cast<void> (0) : __assert_fail ("(Idx == 0 || Idx == 1) && \"Unexpected operation: extracting an unknown landing pad element\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1297, __PRETTY_FUNCTION__));
1298 if (Idx == 0) {
1299 ExtractedEHPtrs.push_back(Extract);
1300 } else if (Idx == 1) {
1301 ExtractedSelectors.push_back(Extract);
1302 }
1303 }
1304}
1305
1306bool LandingPadMap::isOriginLandingPadBlock(const BasicBlock *BB) const {
1307 return BB->getLandingPadInst() == OriginLPad;
1308}
1309
1310bool LandingPadMap::isLandingPadSpecificInst(const Instruction *Inst) const {
1311 if (Inst == OriginLPad)
1312 return true;
1313 for (auto *Extract : ExtractedEHPtrs) {
1314 if (Inst == Extract)
1315 return true;
1316 }
1317 for (auto *Extract : ExtractedSelectors) {
1318 if (Inst == Extract)
1319 return true;
1320 }
1321 return false;
1322}
1323
1324void LandingPadMap::remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
1325 Value *SelectorValue) const {
1326 // Remap all landing pad extract instructions to the specified values.
1327 for (auto *Extract : ExtractedEHPtrs)
1328 VMap[Extract] = EHPtrValue;
1329 for (auto *Extract : ExtractedSelectors)
1330 VMap[Extract] = SelectorValue;
1331}
1332
1333static bool isFrameAddressCall(const Value *V) {
1334 return match(const_cast<Value *>(V),
1335 m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
1336}
1337
1338CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
1339 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1340 // If this is one of the boilerplate landing pad instructions, skip it.
1341 // The instruction will have already been remapped in VMap.
1342 if (LPadMap.isLandingPadSpecificInst(Inst))
1343 return CloningDirector::SkipInstruction;
1344
1345 // Nested landing pads will be cloned as stubs, with just the
1346 // landingpad instruction and an unreachable instruction. When
1347 // all landingpads have been outlined, we'll replace this with the
1348 // llvm.eh.actions call and indirect branch created when the
1349 // landing pad was outlined.
1350 if (auto *LPad = dyn_cast<LandingPadInst>(Inst)) {
1351 return handleLandingPad(VMap, LPad, NewBB);
1352 }
1353
1354 if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
1355 return handleInvoke(VMap, Invoke, NewBB);
1356
1357 if (auto *Resume = dyn_cast<ResumeInst>(Inst))
1358 return handleResume(VMap, Resume, NewBB);
1359
1360 if (auto *Cmp = dyn_cast<CmpInst>(Inst))
1361 return handleCompare(VMap, Cmp, NewBB);
1362
1363 if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
1364 return handleBeginCatch(VMap, Inst, NewBB);
1365 if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
1366 return handleEndCatch(VMap, Inst, NewBB);
1367 if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
1368 return handleTypeIdFor(VMap, Inst, NewBB);
1369
1370 // When outlining llvm.frameaddress(i32 0), remap that to the second argument,
1371 // which is the FP of the parent.
1372 if (isFrameAddressCall(Inst)) {
1373 VMap[Inst] = EstablisherFrame;
1374 return CloningDirector::SkipInstruction;
1375 }
1376
1377 // Continue with the default cloning behavior.
1378 return CloningDirector::CloneInstruction;
1379}
1380
1381CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad(
1382 ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
1383 Instruction *NewInst = LPad->clone();
1384 if (LPad->hasName())
1385 NewInst->setName(LPad->getName());
1386 // Save this correlation for later processing.
1387 NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad;
1388 VMap[LPad] = NewInst;
1389 BasicBlock::InstListType &InstList = NewBB->getInstList();
1390 InstList.push_back(NewInst);
1391 InstList.push_back(new UnreachableInst(NewBB->getContext()));
1392 return CloningDirector::StopCloningBB;
1393}
1394
1395CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
1396 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1397 // The argument to the call is some form of the first element of the
1398 // landingpad aggregate value, but that doesn't matter. It isn't used
1399 // here.
1400 // The second argument is an outparameter where the exception object will be
1401 // stored. Typically the exception object is a scalar, but it can be an
1402 // aggregate when catching by value.
1403 // FIXME: Leave something behind to indicate where the exception object lives
1404 // for this handler. Should it be part of llvm.eh.actions?
1405 assert(ExceptionObjectVar == nullptr && "Multiple calls to "((ExceptionObjectVar == nullptr && "Multiple calls to "
"llvm.eh.begincatch found while " "outlining catch handler."
) ? static_cast<void> (0) : __assert_fail ("ExceptionObjectVar == nullptr && \"Multiple calls to \" \"llvm.eh.begincatch found while \" \"outlining catch handler.\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1407, __PRETTY_FUNCTION__))
1406 "llvm.eh.begincatch found while "((ExceptionObjectVar == nullptr && "Multiple calls to "
"llvm.eh.begincatch found while " "outlining catch handler."
) ? static_cast<void> (0) : __assert_fail ("ExceptionObjectVar == nullptr && \"Multiple calls to \" \"llvm.eh.begincatch found while \" \"outlining catch handler.\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1407, __PRETTY_FUNCTION__))
1407 "outlining catch handler.")((ExceptionObjectVar == nullptr && "Multiple calls to "
"llvm.eh.begincatch found while " "outlining catch handler."
) ? static_cast<void> (0) : __assert_fail ("ExceptionObjectVar == nullptr && \"Multiple calls to \" \"llvm.eh.begincatch found while \" \"outlining catch handler.\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1407, __PRETTY_FUNCTION__));
1408 ExceptionObjectVar = Inst->getOperand(1)->stripPointerCasts();
1409 if (isa<ConstantPointerNull>(ExceptionObjectVar))
1410 return CloningDirector::SkipInstruction;
1411 assert(cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() &&((cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca
() && "catch parameter is not static alloca") ? static_cast
<void> (0) : __assert_fail ("cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() && \"catch parameter is not static alloca\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1412, __PRETTY_FUNCTION__))
1412 "catch parameter is not static alloca")((cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca
() && "catch parameter is not static alloca") ? static_cast
<void> (0) : __assert_fail ("cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() && \"catch parameter is not static alloca\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1412, __PRETTY_FUNCTION__));
1413 Materializer.escapeCatchObject(ExceptionObjectVar);
1414 return CloningDirector::SkipInstruction;
1415}
1416
1417CloningDirector::CloningAction
1418WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap,
1419 const Instruction *Inst, BasicBlock *NewBB) {
1420 auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
1421 // It might be interesting to track whether or not we are inside a catch
1422 // function, but that might make the algorithm more brittle than it needs
1423 // to be.
1424
1425 // The end catch call can occur in one of two places: either in a
1426 // landingpad block that is part of the catch handlers exception mechanism,
1427 // or at the end of the catch block. However, a catch-all handler may call
1428 // end catch from the original landing pad. If the call occurs in a nested
1429 // landing pad block, we must skip it and continue so that the landing pad
1430 // gets cloned.
1431 auto *ParentBB = IntrinCall->getParent();
1432 if (ParentBB->isLandingPad() && !LPadMap.isOriginLandingPadBlock(ParentBB))
1433 return CloningDirector::SkipInstruction;
1434
1435 // If an end catch occurs anywhere else we want to terminate the handler
1436 // with a return to the code that follows the endcatch call. If the
1437 // next instruction is not an unconditional branch, we need to split the
1438 // block to provide a clear target for the return instruction.
1439 BasicBlock *ContinueBB;
1440 auto Next = std::next(BasicBlock::const_iterator(IntrinCall));
1441 const BranchInst *Branch = dyn_cast<BranchInst>(Next);
1442 if (!Branch || !Branch->isUnconditional()) {
1443 // We're interrupting the cloning process at this location, so the
1444 // const_cast we're doing here will not cause a problem.
1445 ContinueBB = SplitBlock(const_cast<BasicBlock *>(ParentBB),
1446 const_cast<Instruction *>(cast<Instruction>(Next)));
1447 } else {
1448 ContinueBB = Branch->getSuccessor(0);
1449 }
1450
1451 ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueBB), NewBB);
1452 ReturnTargets.push_back(ContinueBB);
1453
1454 // We just added a terminator to the cloned block.
1455 // Tell the caller to stop processing the current basic block so that
1456 // the branch instruction will be skipped.
1457 return CloningDirector::StopCloningBB;
1458}
1459
1460CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor(
1461 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1462 auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
1463 Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
1464 // This causes a replacement that will collapse the landing pad CFG based
1465 // on the filter function we intend to match.
1466 if (Selector == CurrentSelector)
1467 VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
1468 else
1469 VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
1470 // Tell the caller not to clone this instruction.
1471 return CloningDirector::SkipInstruction;
1472}
1473
1474CloningDirector::CloningAction
1475WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap,
1476 const InvokeInst *Invoke, BasicBlock *NewBB) {
1477 return CloningDirector::CloneInstruction;
1478}
1479
1480CloningDirector::CloningAction
1481WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap,
1482 const ResumeInst *Resume, BasicBlock *NewBB) {
1483 // Resume instructions shouldn't be reachable from catch handlers.
1484 // We still need to handle it, but it will be pruned.
1485 BasicBlock::InstListType &InstList = NewBB->getInstList();
1486 InstList.push_back(new UnreachableInst(NewBB->getContext()));
1487 return CloningDirector::StopCloningBB;
1488}
1489
1490CloningDirector::CloningAction
1491WinEHCatchDirector::handleCompare(ValueToValueMapTy &VMap,
1492 const CmpInst *Compare, BasicBlock *NewBB) {
1493 const IntrinsicInst *IntrinCall = nullptr;
1494 if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
1495 IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(0));
1496 } else if (match(Compare->getOperand(1), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
1497 IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(1));
1498 }
1499 if (IntrinCall) {
1500 Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
1501 // This causes a replacement that will collapse the landing pad CFG based
1502 // on the filter function we intend to match.
1503 if (Selector == CurrentSelector->stripPointerCasts()) {
1504 VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
1505 }
1506 else {
1507 VMap[Compare] = ConstantInt::get(SelectorIDType, 0);
1508 }
1509 return CloningDirector::SkipInstruction;
1510 }
1511 return CloningDirector::CloneInstruction;
1512}
1513
1514CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad(
1515 ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
1516 // The MS runtime will terminate the process if an exception occurs in a
1517 // cleanup handler, so we shouldn't encounter landing pads in the actual
1518 // cleanup code, but they may appear in catch blocks. Depending on where
1519 // we started cloning we may see one, but it will get dropped during dead
1520 // block pruning.
1521 Instruction *NewInst = new UnreachableInst(NewBB->getContext());
1522 VMap[LPad] = NewInst;
1523 BasicBlock::InstListType &InstList = NewBB->getInstList();
1524 InstList.push_back(NewInst);
1525 return CloningDirector::StopCloningBB;
1526}
1527
1528CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
1529 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1530 // Cleanup code may flow into catch blocks or the catch block may be part
1531 // of a branch that will be optimized away. We'll insert a return
1532 // instruction now, but it may be pruned before the cloning process is
1533 // complete.
1534 ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
1535 return CloningDirector::StopCloningBB;
1536}
1537
1538CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
1539 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1540 // Cleanup handlers nested within catch handlers may begin with a call to
1541 // eh.endcatch. We can just ignore that instruction.
1542 return CloningDirector::SkipInstruction;
1543}
1544
1545CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
1546 ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
1547 // If we encounter a selector comparison while cloning a cleanup handler,
1548 // we want to stop cloning immediately. Anything after the dispatch
1549 // will be outlined into a different handler.
1550 BasicBlock *CatchHandler;
1551 Constant *Selector;
1552 BasicBlock *NextBB;
1553 if (isSelectorDispatch(const_cast<BasicBlock *>(Inst->getParent()),
1554 CatchHandler, Selector, NextBB)) {
1555 ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
1556 return CloningDirector::StopCloningBB;
1557 }
1558 // If eg.typeid.for is called for any other reason, it can be ignored.
1559 VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
1560 return CloningDirector::SkipInstruction;
1561}
1562
1563CloningDirector::CloningAction WinEHCleanupDirector::handleInvoke(
1564 ValueToValueMapTy &VMap, const InvokeInst *Invoke, BasicBlock *NewBB) {
1565 // All invokes in cleanup handlers can be replaced with calls.
1566 SmallVector<Value *, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
1567 // Insert a normal call instruction...
1568 CallInst *NewCall =
1569 CallInst::Create(const_cast<Value *>(Invoke->getCalledValue()), CallArgs,
1570 Invoke->getName(), NewBB);
1571 NewCall->setCallingConv(Invoke->getCallingConv());
1572 NewCall->setAttributes(Invoke->getAttributes());
1573 NewCall->setDebugLoc(Invoke->getDebugLoc());
1574 VMap[Invoke] = NewCall;
1575
1576 // Remap the operands.
1577 llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer);
1578
1579 // Insert an unconditional branch to the normal destination.
1580 BranchInst::Create(Invoke->getNormalDest(), NewBB);
1581
1582 // The unwind destination won't be cloned into the new function, so
1583 // we don't need to clean up its phi nodes.
1584
1585 // We just added a terminator to the cloned block.
1586 // Tell the caller to stop processing the current basic block.
1587 return CloningDirector::CloneSuccessors;
1588}
1589
1590CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
1591 ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) {
1592 ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
1593
1594 // We just added a terminator to the cloned block.
1595 // Tell the caller to stop processing the current basic block so that
1596 // the branch instruction will be skipped.
1597 return CloningDirector::StopCloningBB;
1598}
1599
1600CloningDirector::CloningAction
1601WinEHCleanupDirector::handleCompare(ValueToValueMapTy &VMap,
1602 const CmpInst *Compare, BasicBlock *NewBB) {
1603 if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>()) ||
1604 match(Compare->getOperand(1), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
1605 VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
1606 return CloningDirector::SkipInstruction;
1607 }
1608 return CloningDirector::CloneInstruction;
1609
1610}
1611
1612WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
1613 Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
1614 : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
1615 BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
1616 Builder.SetInsertPoint(EntryBB, EntryBB->getFirstInsertionPt());
1617}
1618
1619Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
1620 // If we're asked to materialize a static alloca, we temporarily create an
1621 // alloca in the outlined function and add this to the FrameVarInfo map. When
1622 // all the outlining is complete, we'll replace these temporary allocas with
1623 // calls to llvm.framerecover.
1624 if (auto *AV = dyn_cast<AllocaInst>(V)) {
1625 assert(AV->isStaticAlloca() &&((AV->isStaticAlloca() && "cannot materialize un-demoted dynamic alloca"
) ? static_cast<void> (0) : __assert_fail ("AV->isStaticAlloca() && \"cannot materialize un-demoted dynamic alloca\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1626, __PRETTY_FUNCTION__))
1626 "cannot materialize un-demoted dynamic alloca")((AV->isStaticAlloca() && "cannot materialize un-demoted dynamic alloca"
) ? static_cast<void> (0) : __assert_fail ("AV->isStaticAlloca() && \"cannot materialize un-demoted dynamic alloca\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1626, __PRETTY_FUNCTION__));
1627 AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone());
1628 Builder.Insert(NewAlloca, AV->getName());
1629 FrameVarInfo[AV].push_back(NewAlloca);
1630 return NewAlloca;
1631 }
1632
1633 if (isa<Instruction>(V) || isa<Argument>(V)) {
1634 errs() << "Failed to demote instruction used in exception handler:\n";
1635 errs() << " " << *V << '\n';
1636 report_fatal_error("WinEHPrepare failed to demote instruction");
1637 }
1638
1639 // Don't materialize other values.
1640 return nullptr;
1641}
1642
1643void WinEHFrameVariableMaterializer::escapeCatchObject(Value *V) {
1644 // Catch parameter objects have to live in the parent frame. When we see a use
1645 // of a catch parameter, add a sentinel to the multimap to indicate that it's
1646 // used from another handler. This will prevent us from trying to sink the
1647 // alloca into the handler and ensure that the catch parameter is present in
1648 // the call to llvm.frameescape.
1649 FrameVarInfo[V].push_back(getCatchObjectSentinel());
1650}
1651
1652// This function maps the catch and cleanup handlers that are reachable from the
1653// specified landing pad. The landing pad sequence will have this basic shape:
1654//
1655// <cleanup handler>
1656// <selector comparison>
1657// <catch handler>
1658// <cleanup handler>
1659// <selector comparison>
1660// <catch handler>
1661// <cleanup handler>
1662// ...
1663//
1664// Any of the cleanup slots may be absent. The cleanup slots may be occupied by
1665// any arbitrary control flow, but all paths through the cleanup code must
1666// eventually reach the next selector comparison and no path can skip to a
1667// different selector comparisons, though some paths may terminate abnormally.
1668// Therefore, we will use a depth first search from the start of any given
1669// cleanup block and stop searching when we find the next selector comparison.
1670//
1671// If the landingpad instruction does not have a catch clause, we will assume
1672// that any instructions other than selector comparisons and catch handlers can
1673// be ignored. In practice, these will only be the boilerplate instructions.
1674//
1675// The catch handlers may also have any control structure, but we are only
1676// interested in the start of the catch handlers, so we don't need to actually
1677// follow the flow of the catch handlers. The start of the catch handlers can
1678// be located from the compare instructions, but they can be skipped in the
1679// flow by following the contrary branch.
1680void WinEHPrepare::mapLandingPadBlocks(LandingPadInst *LPad,
1681 LandingPadActions &Actions) {
1682 unsigned int NumClauses = LPad->getNumClauses();
1683 unsigned int HandlersFound = 0;
1684 BasicBlock *BB = LPad->getParent();
1685
1686 DEBUG(dbgs() << "Mapping landing pad: " << BB->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << "Mapping landing pad: " <<
BB->getName() << "\n"; } } while (0);
1687
1688 if (NumClauses == 0) {
1
Assuming 'NumClauses' is not equal to 0
→
2
←
Taking false branch
→
1689 findCleanupHandlers(Actions, BB, nullptr);
1690 return;
1691 }
1692
1693 VisitedBlockSet VisitedBlocks;
1694
1695 while (HandlersFound != NumClauses) {
3
←
Loop condition is true. Entering loop body
→
8
←
Loop condition is true. Entering loop body
→
13
←
Assuming 'HandlersFound' is not equal to 'NumClauses'
→
14
←
Loop condition is true. Entering loop body
→
1696 BasicBlock *NextBB = nullptr;
1697
1698 // Skip over filter clauses.
1699 if (LPad->isFilter(HandlersFound)) {
4
←
Taking false branch
→
9
←
Taking false branch
→
15
←
Taking false branch
→
1700 ++HandlersFound;
1701 continue;
1702 }
1703
1704 // See if the clause we're looking for is a catch-all.
1705 // If so, the catch begins immediately.
1706 Constant *ExpectedSelector = LPad->getClause(HandlersFound)->stripPointerCasts();
1707 if (isa<ConstantPointerNull>(ExpectedSelector)) {
5
←
Taking false branch
→
10
←
Taking false branch
→
16
←
Taking true branch
→
1708 // The catch all must occur last.
1709 assert(HandlersFound == NumClauses - 1)((HandlersFound == NumClauses - 1) ? static_cast<void> (
0) : __assert_fail ("HandlersFound == NumClauses - 1", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1709, __PRETTY_FUNCTION__));
1710
1711 // There can be additional selector dispatches in the call chain that we
1712 // need to ignore.
1713 BasicBlock *CatchBlock = nullptr;
1714 Constant *Selector;
1715 while (BB && isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
17
←
Assuming pointer value is null
→
1716 DEBUG(dbgs() << " Found extra catch dispatch in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found extra catch dispatch in block "
<< CatchBlock->getName() << "\n"; } } while (
0)
1717 << CatchBlock->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found extra catch dispatch in block "
<< CatchBlock->getName() << "\n"; } } while (
0);
1718 BB = NextBB;
1719 }
1720
1721 // For C++ EH, check if there is any interesting cleanup code before we
1722 // begin the catch. This is important because cleanups cannot rethrow
1723 // exceptions but code called from catches can. For SEH, it isn't
1724 // important if some finally code before a catch-all is executed out of
1725 // line or after recovering from the exception.
1726 if (Personality == EHPersonality::MSVC_CXX)
18
←
Taking false branch
→
1727 findCleanupHandlers(Actions, BB, BB);
1728
1729 // Add the catch handler to the action list.
1730 CatchHandler *Action = nullptr;
1731 if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
1732 // If the CatchHandlerMap already has an entry for this BB, re-use it.
1733 Action = CatchHandlerMap[BB];
1734 assert(Action->getSelector() == ExpectedSelector)((Action->getSelector() == ExpectedSelector) ? static_cast
<void> (0) : __assert_fail ("Action->getSelector() == ExpectedSelector"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1734, __PRETTY_FUNCTION__));
1735 } else {
1736 // Since this is a catch-all handler, the selector won't actually appear
1737 // in the code anywhere. ExpectedSelector here is the constant null ptr
1738 // that we got from the landing pad instruction.
1739 Action = new CatchHandler(BB, ExpectedSelector, nullptr);
1740 CatchHandlerMap[BB] = Action;
1741 }
1742 Actions.insertCatchHandler(Action);
1743 DEBUG(dbgs() << " Catch all handler at block " << BB->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Catch all handler at block "
<< BB->getName() << "\n"; } } while (0);
19
←
Within the expansion of the macro 'DEBUG':
a
Called C++ object pointer is null
1744 ++HandlersFound;
1745
1746 // Once we reach a catch-all, don't expect to hit a resume instruction.
1747 BB = nullptr;
1748 break;
1749 }
1750
1751 CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
1752 assert(CatchAction)((CatchAction) ? static_cast<void> (0) : __assert_fail (
"CatchAction", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 1752, __PRETTY_FUNCTION__));
1753
1754 // See if there is any interesting code executed before the dispatch.
1755 findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
1756
1757 // When the source program contains multiple nested try blocks the catch
1758 // handlers can get strung together in such a way that we can encounter
1759 // a dispatch for a selector that we've already had a handler for.
1760 if (CatchAction->getSelector()->stripPointerCasts() == ExpectedSelector) {
6
←
Taking false branch
→
11
←
Taking true branch
→
1761 ++HandlersFound;
1762
1763 // Add the catch handler to the action list.
1764 DEBUG(dbgs() << " Found catch dispatch in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found catch dispatch in block "
<< CatchAction->getStartBlock()->getName() <<
"\n"; } } while (0)
1765 << CatchAction->getStartBlock()->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found catch dispatch in block "
<< CatchAction->getStartBlock()->getName() <<
"\n"; } } while (0);
1766 Actions.insertCatchHandler(CatchAction);
1767 } else {
1768 // Under some circumstances optimized IR will flow unconditionally into a
1769 // handler block without checking the selector. This can only happen if
1770 // the landing pad has a catch-all handler and the handler for the
1771 // preceeding catch clause is identical to the catch-call handler
1772 // (typically an empty catch). In this case, the handler must be shared
1773 // by all remaining clauses.
1774 if (isa<ConstantPointerNull>(
7
←
Taking false branch
→
1775 CatchAction->getSelector()->stripPointerCasts())) {
1776 DEBUG(dbgs() << " Applying early catch-all handler in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Applying early catch-all handler in block "
<< CatchAction->getStartBlock()->getName() <<
" to all remaining clauses.\n"; } } while (0)
1777 << CatchAction->getStartBlock()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Applying early catch-all handler in block "
<< CatchAction->getStartBlock()->getName() <<
" to all remaining clauses.\n"; } } while (0)
1778 << " to all remaining clauses.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Applying early catch-all handler in block "
<< CatchAction->getStartBlock()->getName() <<
" to all remaining clauses.\n"; } } while (0);
1779 Actions.insertCatchHandler(CatchAction);
1780 return;
1781 }
1782
1783 DEBUG(dbgs() << " Found extra catch dispatch in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found extra catch dispatch in block "
<< CatchAction->getStartBlock()->getName() <<
"\n"; } } while (0)
1784 << CatchAction->getStartBlock()->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found extra catch dispatch in block "
<< CatchAction->getStartBlock()->getName() <<
"\n"; } } while (0);
1785 }
1786
1787 // Move on to the block after the catch handler.
1788 BB = NextBB;
12
←
Value assigned to 'BB'
→
1789 }
1790
1791 // If we didn't wind up in a catch-all, see if there is any interesting code
1792 // executed before the resume.
1793 findCleanupHandlers(Actions, BB, BB);
1794
1795 // It's possible that some optimization moved code into a landingpad that
1796 // wasn't
1797 // previously being used for cleanup. If that happens, we need to execute
1798 // that
1799 // extra code from a cleanup handler.
1800 if (Actions.includesCleanup() && !LPad->isCleanup())
1801 LPad->setCleanup(true);
1802}
1803
1804// This function searches starting with the input block for the next
1805// block that terminates with a branch whose condition is based on a selector
1806// comparison. This may be the input block. See the mapLandingPadBlocks
1807// comments for a discussion of control flow assumptions.
1808//
1809CatchHandler *WinEHPrepare::findCatchHandler(BasicBlock *BB,
1810 BasicBlock *&NextBB,
1811 VisitedBlockSet &VisitedBlocks) {
1812 // See if we've already found a catch handler use it.
1813 // Call count() first to avoid creating a null entry for blocks
1814 // we haven't seen before.
1815 if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
1816 CatchHandler *Action = cast<CatchHandler>(CatchHandlerMap[BB]);
1817 NextBB = Action->getNextBB();
1818 return Action;
1819 }
1820
1821 // VisitedBlocks applies only to the current search. We still
1822 // need to consider blocks that we've visited while mapping other
1823 // landing pads.
1824 VisitedBlocks.insert(BB);
1825
1826 BasicBlock *CatchBlock = nullptr;
1827 Constant *Selector = nullptr;
1828
1829 // If this is the first time we've visited this block from any landing pad
1830 // look to see if it is a selector dispatch block.
1831 if (!CatchHandlerMap.count(BB)) {
1832 if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
1833 CatchHandler *Action = new CatchHandler(BB, Selector, NextBB);
1834 CatchHandlerMap[BB] = Action;
1835 return Action;
1836 }
1837 // If we encounter a block containing an llvm.eh.begincatch before we
1838 // find a selector dispatch block, the handler is assumed to be
1839 // reached unconditionally. This happens for catch-all blocks, but
1840 // it can also happen for other catch handlers that have been combined
1841 // with the catch-all handler during optimization.
1842 if (isCatchBlock(BB)) {
1843 PointerType *Int8PtrTy = Type::getInt8PtrTy(BB->getContext());
1844 Constant *NullSelector = ConstantPointerNull::get(Int8PtrTy);
1845 CatchHandler *Action = new CatchHandler(BB, NullSelector, nullptr);
1846 CatchHandlerMap[BB] = Action;
1847 return Action;
1848 }
1849 }
1850
1851 // Visit each successor, looking for the dispatch.
1852 // FIXME: We expect to find the dispatch quickly, so this will probably
1853 // work better as a breadth first search.
1854 for (BasicBlock *Succ : successors(BB)) {
1855 if (VisitedBlocks.count(Succ))
1856 continue;
1857
1858 CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks);
1859 if (Action)
1860 return Action;
1861 }
1862 return nullptr;
1863}
1864
1865// These are helper functions to combine repeated code from findCleanupHandlers.
1866static void createCleanupHandler(LandingPadActions &Actions,
1867 CleanupHandlerMapTy &CleanupHandlerMap,
1868 BasicBlock *BB) {
1869 CleanupHandler *Action = new CleanupHandler(BB);
1870 CleanupHandlerMap[BB] = Action;
1871 Actions.insertCleanupHandler(Action);
1872 DEBUG(dbgs() << " Found cleanup code in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found cleanup code in block "
<< Action->getStartBlock()->getName() << "\n"
; } } while (0)
1873 << Action->getStartBlock()->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found cleanup code in block "
<< Action->getStartBlock()->getName() << "\n"
; } } while (0);
1874}
1875
1876static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
1877 Instruction *MaybeCall) {
1878 // Look for finally blocks that Clang has already outlined for us.
1879 // %fp = call i8* @llvm.frameaddress(i32 0)
1880 // call void @"fin$parent"(iN 1, i8* %fp)
1881 if (isFrameAddressCall(MaybeCall) && MaybeCall != BB->getTerminator())
1882 MaybeCall = MaybeCall->getNextNode();
1883 CallSite FinallyCall(MaybeCall);
1884 if (!FinallyCall || FinallyCall.arg_size() != 2)
1885 return CallSite();
1886 if (!match(FinallyCall.getArgument(0), m_SpecificInt(1)))
1887 return CallSite();
1888 if (!isFrameAddressCall(FinallyCall.getArgument(1)))
1889 return CallSite();
1890 return FinallyCall;
1891}
1892
1893static BasicBlock *followSingleUnconditionalBranches(BasicBlock *BB) {
1894 // Skip single ubr blocks.
1895 while (BB->getFirstNonPHIOrDbg() == BB->getTerminator()) {
1896 auto *Br = dyn_cast<BranchInst>(BB->getTerminator());
1897 if (Br && Br->isUnconditional())
1898 BB = Br->getSuccessor(0);
1899 else
1900 return BB;
1901 }
1902 return BB;
1903}
1904
1905// This function searches starting with the input block for the next block that
1906// contains code that is not part of a catch handler and would not be eliminated
1907// during handler outlining.
1908//
1909void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions,
1910 BasicBlock *StartBB, BasicBlock *EndBB) {
1911 // Here we will skip over the following:
1912 //
1913 // landing pad prolog:
1914 //
1915 // Unconditional branches
1916 //
1917 // Selector dispatch
1918 //
1919 // Resume pattern
1920 //
1921 // Anything else marks the start of an interesting block
1922
1923 BasicBlock *BB = StartBB;
1924 // Anything other than an unconditional branch will kick us out of this loop
1925 // one way or another.
1926 while (BB) {
1927 BB = followSingleUnconditionalBranches(BB);
1928 // If we've already scanned this block, don't scan it again. If it is
1929 // a cleanup block, there will be an action in the CleanupHandlerMap.
1930 // If we've scanned it and it is not a cleanup block, there will be a
1931 // nullptr in the CleanupHandlerMap. If we have not scanned it, there will
1932 // be no entry in the CleanupHandlerMap. We must call count() first to
1933 // avoid creating a null entry for blocks we haven't scanned.
1934 if (CleanupHandlerMap.count(BB)) {
1935 if (auto *Action = CleanupHandlerMap[BB]) {
1936 Actions.insertCleanupHandler(Action);
1937 DEBUG(dbgs() << " Found cleanup code in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found cleanup code in block "
<< Action->getStartBlock()->getName() << "\n"
; } } while (0)
1938 << Action->getStartBlock()->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found cleanup code in block "
<< Action->getStartBlock()->getName() << "\n"
; } } while (0);
1939 // FIXME: This cleanup might chain into another, and we need to discover
1940 // that.
1941 return;
1942 } else {
1943 // Here we handle the case where the cleanup handler map contains a
1944 // value for this block but the value is a nullptr. This means that
1945 // we have previously analyzed the block and determined that it did
1946 // not contain any cleanup code. Based on the earlier analysis, we
1947 // know the the block must end in either an unconditional branch, a
1948 // resume or a conditional branch that is predicated on a comparison
1949 // with a selector. Either the resume or the selector dispatch
1950 // would terminate the search for cleanup code, so the unconditional
1951 // branch is the only case for which we might need to continue
1952 // searching.
1953 BasicBlock *SuccBB = followSingleUnconditionalBranches(BB);
1954 if (SuccBB == BB || SuccBB == EndBB)
1955 return;
1956 BB = SuccBB;
1957 continue;
1958 }
1959 }
1960
1961 // Create an entry in the cleanup handler map for this block. Initially
1962 // we create an entry that says this isn't a cleanup block. If we find
1963 // cleanup code, the caller will replace this entry.
1964 CleanupHandlerMap[BB] = nullptr;
1965
1966 TerminatorInst *Terminator = BB->getTerminator();
1967
1968 // Landing pad blocks have extra instructions we need to accept.
1969 LandingPadMap *LPadMap = nullptr;
1970 if (BB->isLandingPad()) {
1971 LandingPadInst *LPad = BB->getLandingPadInst();
1972 LPadMap = &LPadMaps[LPad];
1973 if (!LPadMap->isInitialized())
1974 LPadMap->mapLandingPad(LPad);
1975 }
1976
1977 // Look for the bare resume pattern:
1978 // %lpad.val1 = insertvalue { i8*, i32 } undef, i8* %exn, 0
1979 // %lpad.val2 = insertvalue { i8*, i32 } %lpad.val1, i32 %sel, 1
1980 // resume { i8*, i32 } %lpad.val2
1981 if (auto *Resume = dyn_cast<ResumeInst>(Terminator)) {
1982 InsertValueInst *Insert1 = nullptr;
1983 InsertValueInst *Insert2 = nullptr;
1984 Value *ResumeVal = Resume->getOperand(0);
1985 // If the resume value isn't a phi or landingpad value, it should be a
1986 // series of insertions. Identify them so we can avoid them when scanning
1987 // for cleanups.
1988 if (!isa<PHINode>(ResumeVal) && !isa<LandingPadInst>(ResumeVal)) {
1989 Insert2 = dyn_cast<InsertValueInst>(ResumeVal);
1990 if (!Insert2)
1991 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
1992 Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand());
1993 if (!Insert1)
1994 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
1995 }
1996 for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
1997 II != IE; ++II) {
1998 Instruction *Inst = II;
1999 if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
2000 continue;
2001 if (Inst == Insert1 || Inst == Insert2 || Inst == Resume)
2002 continue;
2003 if (!Inst->hasOneUse() ||
2004 (Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) {
2005 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
2006 }
2007 }
2008 return;
2009 }
2010
2011 BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
2012 if (Branch && Branch->isConditional()) {
2013 // Look for the selector dispatch.
2014 // %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
2015 // %matches = icmp eq i32 %sel, %2
2016 // br i1 %matches, label %catch14, label %eh.resume
2017 CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition());
2018 if (!Compare || !Compare->isEquality())
2019 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
2020 for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
2021 II != IE; ++II) {
2022 Instruction *Inst = II;
2023 if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
2024 continue;
2025 if (Inst == Compare || Inst == Branch)
2026 continue;
2027 if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
2028 continue;
2029 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
2030 }
2031 // The selector dispatch block should always terminate our search.
2032 assert(BB == EndBB)((BB == EndBB) ? static_cast<void> (0) : __assert_fail (
"BB == EndBB", "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 2032, __PRETTY_FUNCTION__));
2033 return;
2034 }
2035
2036 if (isAsynchronousEHPersonality(Personality)) {
2037 // If this is a landingpad block, split the block at the first non-landing
2038 // pad instruction.
2039 Instruction *MaybeCall = BB->getFirstNonPHIOrDbg();
2040 if (LPadMap) {
2041 while (MaybeCall != BB->getTerminator() &&
2042 LPadMap->isLandingPadSpecificInst(MaybeCall))
2043 MaybeCall = MaybeCall->getNextNode();
2044 }
2045
2046 // Look for outlined finally calls.
2047 if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) {
2048 Function *Fin = FinallyCall.getCalledFunction();
2049 assert(Fin && "outlined finally call should be direct")((Fin && "outlined finally call should be direct") ? static_cast
<void> (0) : __assert_fail ("Fin && \"outlined finally call should be direct\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 2049, __PRETTY_FUNCTION__));
2050 auto *Action = new CleanupHandler(BB);
2051 Action->setHandlerBlockOrFunc(Fin);
2052 Actions.insertCleanupHandler(Action);
2053 CleanupHandlerMap[BB] = Action;
2054 DEBUG(dbgs() << " Found frontend-outlined finally call to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found frontend-outlined finally call to "
<< Fin->getName() << " in block " << Action
->getStartBlock()->getName() << "\n"; } } while (
0)
2055 << Fin->getName() << " in block "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found frontend-outlined finally call to "
<< Fin->getName() << " in block " << Action
->getStartBlock()->getName() << "\n"; } } while (
0)
2056 << Action->getStartBlock()->getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("winehprepare")) { dbgs() << " Found frontend-outlined finally call to "
<< Fin->getName() << " in block " << Action
->getStartBlock()->getName() << "\n"; } } while (
0);
2057
2058 // Split the block if there were more interesting instructions and look
2059 // for finally calls in the normal successor block.
2060 BasicBlock *SuccBB = BB;
2061 if (FinallyCall.getInstruction() != BB->getTerminator() &&
2062 FinallyCall.getInstruction()->getNextNode() != BB->getTerminator()) {
2063 SuccBB = BB->splitBasicBlock(FinallyCall.getInstruction()->getNextNode());
2064 } else {
2065 if (FinallyCall.isInvoke()) {
2066 SuccBB = cast<InvokeInst>(FinallyCall.getInstruction())->getNormalDest();
2067 } else {
2068 SuccBB = BB->getUniqueSuccessor();
2069 assert(SuccBB && "splitOutlinedFinallyCalls didn't insert a branch")((SuccBB && "splitOutlinedFinallyCalls didn't insert a branch"
) ? static_cast<void> (0) : __assert_fail ("SuccBB && \"splitOutlinedFinallyCalls didn't insert a branch\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 2069, __PRETTY_FUNCTION__));
2070 }
2071 }
2072 BB = SuccBB;
2073 if (BB == EndBB)
2074 return;
2075 continue;
2076 }
2077 }
2078
2079 // Anything else is either a catch block or interesting cleanup code.
2080 for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
2081 II != IE; ++II) {
2082 Instruction *Inst = II;
2083 if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
2084 continue;
2085 // Unconditional branches fall through to this loop.
2086 if (Inst == Branch)
2087 continue;
2088 // If this is a catch block, there is no cleanup code to be found.
2089 if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
2090 return;
2091 // If this a nested landing pad, it may contain an endcatch call.
2092 if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
2093 return;
2094 // Anything else makes this interesting cleanup code.
2095 return createCleanupHandler(Actions, CleanupHandlerMap, BB);
2096 }
2097
2098 // Only unconditional branches in empty blocks should get this far.
2099 assert(Branch && Branch->isUnconditional())((Branch && Branch->isUnconditional()) ? static_cast
<void> (0) : __assert_fail ("Branch && Branch->isUnconditional()"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 2099, __PRETTY_FUNCTION__));
2100 if (BB == EndBB)
2101 return;
2102 BB = Branch->getSuccessor(0);
2103 }
2104}
2105
2106// This is a public function, declared in WinEHFuncInfo.h and is also
2107// referenced by WinEHNumbering in FunctionLoweringInfo.cpp.
2108void llvm::parseEHActions(const IntrinsicInst *II,
2109 SmallVectorImpl<ActionHandler *> &Actions) {
2110 for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
2111 uint64_t ActionKind =
2112 cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
2113 if (ActionKind == /*catch=*/1) {
2114 auto *Selector = cast<Constant>(II->getArgOperand(I + 1));
2115 ConstantInt *EHObjIndex = cast<ConstantInt>(II->getArgOperand(I + 2));
2116 int64_t EHObjIndexVal = EHObjIndex->getSExtValue();
2117 Constant *Handler = cast<Constant>(II->getArgOperand(I + 3));
2118 I += 4;
2119 auto *CH = new CatchHandler(/*BB=*/nullptr, Selector, /*NextBB=*/nullptr);
2120 CH->setHandlerBlockOrFunc(Handler);
2121 CH->setExceptionVarIndex(EHObjIndexVal);
2122 Actions.push_back(CH);
2123 } else if (ActionKind == 0) {
2124 Constant *Handler = cast<Constant>(II->getArgOperand(I + 1));
2125 I += 2;
2126 auto *CH = new CleanupHandler(/*BB=*/nullptr);
2127 CH->setHandlerBlockOrFunc(Handler);
2128 Actions.push_back(CH);
2129 } else {
2130 llvm_unreachable("Expected either a catch or cleanup handler!")::llvm::llvm_unreachable_internal("Expected either a catch or cleanup handler!"
, "/tmp/buildd/llvm-toolchain-snapshot-3.7~svn235822/lib/CodeGen/WinEHPrepare.cpp"
, 2130);
2131 }
2132 }
2133 std::reverse(Actions.begin(), Actions.end());
2134}