1 //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
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 contains code to emit Stmt nodes as LLVM code.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "CodeGenFunction.h"
15 #include "CGDebugInfo.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/StmtVisitor.h"
19 #include "clang/Basic/PrettyStackTrace.h"
20 #include "clang/Basic/TargetInfo.h"
21 #include "clang/Sema/LoopHint.h"
22 #include "clang/Sema/SemaDiagnostic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/IR/CallSite.h"
25 #include "llvm/IR/DataLayout.h"
26 #include "llvm/IR/InlineAsm.h"
27 #include "llvm/IR/Intrinsics.h"
28 using namespace clang;
29 using namespace CodeGen;
30
31 //===----------------------------------------------------------------------===//
32 // Statement Emission
33 //===----------------------------------------------------------------------===//
34
EmitStopPoint(const Stmt * S)35 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
36 if (CGDebugInfo *DI = getDebugInfo()) {
37 SourceLocation Loc;
38 Loc = S->getLocStart();
39 DI->EmitLocation(Builder, Loc);
40
41 LastStopPoint = Loc;
42 }
43 }
44
EmitStmt(const Stmt * S)45 void CodeGenFunction::EmitStmt(const Stmt *S) {
46 assert(S && "Null statement?");
47 PGO.setCurrentStmt(S);
48
49 // These statements have their own debug info handling.
50 if (EmitSimpleStmt(S))
51 return;
52
53 // Check if we are generating unreachable code.
54 if (!HaveInsertPoint()) {
55 // If so, and the statement doesn't contain a label, then we do not need to
56 // generate actual code. This is safe because (1) the current point is
57 // unreachable, so we don't need to execute the code, and (2) we've already
58 // handled the statements which update internal data structures (like the
59 // local variable map) which could be used by subsequent statements.
60 if (!ContainsLabel(S)) {
61 // Verify that any decl statements were handled as simple, they may be in
62 // scope of subsequent reachable statements.
63 assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
64 return;
65 }
66
67 // Otherwise, make a new block to hold the code.
68 EnsureInsertPoint();
69 }
70
71 // Generate a stoppoint if we are emitting debug info.
72 EmitStopPoint(S);
73
74 switch (S->getStmtClass()) {
75 case Stmt::NoStmtClass:
76 case Stmt::CXXCatchStmtClass:
77 case Stmt::SEHExceptStmtClass:
78 case Stmt::SEHFinallyStmtClass:
79 case Stmt::MSDependentExistsStmtClass:
80 llvm_unreachable("invalid statement class to emit generically");
81 case Stmt::NullStmtClass:
82 case Stmt::CompoundStmtClass:
83 case Stmt::DeclStmtClass:
84 case Stmt::LabelStmtClass:
85 case Stmt::AttributedStmtClass:
86 case Stmt::GotoStmtClass:
87 case Stmt::BreakStmtClass:
88 case Stmt::ContinueStmtClass:
89 case Stmt::DefaultStmtClass:
90 case Stmt::CaseStmtClass:
91 case Stmt::SEHLeaveStmtClass:
92 llvm_unreachable("should have emitted these statements as simple");
93
94 #define STMT(Type, Base)
95 #define ABSTRACT_STMT(Op)
96 #define EXPR(Type, Base) \
97 case Stmt::Type##Class:
98 #include "clang/AST/StmtNodes.inc"
99 {
100 // Remember the block we came in on.
101 llvm::BasicBlock *incoming = Builder.GetInsertBlock();
102 assert(incoming && "expression emission must have an insertion point");
103
104 EmitIgnoredExpr(cast<Expr>(S));
105
106 llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
107 assert(outgoing && "expression emission cleared block!");
108
109 // The expression emitters assume (reasonably!) that the insertion
110 // point is always set. To maintain that, the call-emission code
111 // for noreturn functions has to enter a new block with no
112 // predecessors. We want to kill that block and mark the current
113 // insertion point unreachable in the common case of a call like
114 // "exit();". Since expression emission doesn't otherwise create
115 // blocks with no predecessors, we can just test for that.
116 // However, we must be careful not to do this to our incoming
117 // block, because *statement* emission does sometimes create
118 // reachable blocks which will have no predecessors until later in
119 // the function. This occurs with, e.g., labels that are not
120 // reachable by fallthrough.
121 if (incoming != outgoing && outgoing->use_empty()) {
122 outgoing->eraseFromParent();
123 Builder.ClearInsertionPoint();
124 }
125 break;
126 }
127
128 case Stmt::IndirectGotoStmtClass:
129 EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
130
131 case Stmt::IfStmtClass: EmitIfStmt(cast<IfStmt>(*S)); break;
132 case Stmt::WhileStmtClass: EmitWhileStmt(cast<WhileStmt>(*S)); break;
133 case Stmt::DoStmtClass: EmitDoStmt(cast<DoStmt>(*S)); break;
134 case Stmt::ForStmtClass: EmitForStmt(cast<ForStmt>(*S)); break;
135
136 case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break;
137
138 case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break;
139 case Stmt::GCCAsmStmtClass: // Intentional fall-through.
140 case Stmt::MSAsmStmtClass: EmitAsmStmt(cast<AsmStmt>(*S)); break;
141 case Stmt::CapturedStmtClass: {
142 const CapturedStmt *CS = cast<CapturedStmt>(S);
143 EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
144 }
145 break;
146 case Stmt::ObjCAtTryStmtClass:
147 EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
148 break;
149 case Stmt::ObjCAtCatchStmtClass:
150 llvm_unreachable(
151 "@catch statements should be handled by EmitObjCAtTryStmt");
152 case Stmt::ObjCAtFinallyStmtClass:
153 llvm_unreachable(
154 "@finally statements should be handled by EmitObjCAtTryStmt");
155 case Stmt::ObjCAtThrowStmtClass:
156 EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
157 break;
158 case Stmt::ObjCAtSynchronizedStmtClass:
159 EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
160 break;
161 case Stmt::ObjCForCollectionStmtClass:
162 EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
163 break;
164 case Stmt::ObjCAutoreleasePoolStmtClass:
165 EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
166 break;
167
168 case Stmt::CXXTryStmtClass:
169 EmitCXXTryStmt(cast<CXXTryStmt>(*S));
170 break;
171 case Stmt::CXXForRangeStmtClass:
172 EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S));
173 break;
174 case Stmt::SEHTryStmtClass:
175 EmitSEHTryStmt(cast<SEHTryStmt>(*S));
176 break;
177 case Stmt::OMPParallelDirectiveClass:
178 EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
179 break;
180 case Stmt::OMPSimdDirectiveClass:
181 EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
182 break;
183 case Stmt::OMPForDirectiveClass:
184 EmitOMPForDirective(cast<OMPForDirective>(*S));
185 break;
186 case Stmt::OMPForSimdDirectiveClass:
187 EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
188 break;
189 case Stmt::OMPSectionsDirectiveClass:
190 EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
191 break;
192 case Stmt::OMPSectionDirectiveClass:
193 EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
194 break;
195 case Stmt::OMPSingleDirectiveClass:
196 EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
197 break;
198 case Stmt::OMPMasterDirectiveClass:
199 EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
200 break;
201 case Stmt::OMPCriticalDirectiveClass:
202 EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
203 break;
204 case Stmt::OMPParallelForDirectiveClass:
205 EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
206 break;
207 case Stmt::OMPParallelForSimdDirectiveClass:
208 EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
209 break;
210 case Stmt::OMPParallelSectionsDirectiveClass:
211 EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
212 break;
213 case Stmt::OMPTaskDirectiveClass:
214 EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
215 break;
216 case Stmt::OMPTaskyieldDirectiveClass:
217 EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
218 break;
219 case Stmt::OMPBarrierDirectiveClass:
220 EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
221 break;
222 case Stmt::OMPTaskwaitDirectiveClass:
223 EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
224 break;
225 case Stmt::OMPFlushDirectiveClass:
226 EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
227 break;
228 case Stmt::OMPOrderedDirectiveClass:
229 EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
230 break;
231 case Stmt::OMPAtomicDirectiveClass:
232 EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
233 break;
234 case Stmt::OMPTargetDirectiveClass:
235 EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
236 break;
237 case Stmt::OMPTeamsDirectiveClass:
238 EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
239 break;
240 }
241 }
242
EmitSimpleStmt(const Stmt * S)243 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S) {
244 switch (S->getStmtClass()) {
245 default: return false;
246 case Stmt::NullStmtClass: break;
247 case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break;
248 case Stmt::DeclStmtClass: EmitDeclStmt(cast<DeclStmt>(*S)); break;
249 case Stmt::LabelStmtClass: EmitLabelStmt(cast<LabelStmt>(*S)); break;
250 case Stmt::AttributedStmtClass:
251 EmitAttributedStmt(cast<AttributedStmt>(*S)); break;
252 case Stmt::GotoStmtClass: EmitGotoStmt(cast<GotoStmt>(*S)); break;
253 case Stmt::BreakStmtClass: EmitBreakStmt(cast<BreakStmt>(*S)); break;
254 case Stmt::ContinueStmtClass: EmitContinueStmt(cast<ContinueStmt>(*S)); break;
255 case Stmt::DefaultStmtClass: EmitDefaultStmt(cast<DefaultStmt>(*S)); break;
256 case Stmt::CaseStmtClass: EmitCaseStmt(cast<CaseStmt>(*S)); break;
257 case Stmt::SEHLeaveStmtClass: EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S)); break;
258 }
259
260 return true;
261 }
262
263 /// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true,
264 /// this captures the expression result of the last sub-statement and returns it
265 /// (for use by the statement expression extension).
EmitCompoundStmt(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)266 llvm::Value* CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
267 AggValueSlot AggSlot) {
268 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
269 "LLVM IR generation of compound statement ('{}')");
270
271 // Keep track of the current cleanup stack depth, including debug scopes.
272 LexicalScope Scope(*this, S.getSourceRange());
273
274 return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
275 }
276
277 llvm::Value*
EmitCompoundStmtWithoutScope(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)278 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
279 bool GetLast,
280 AggValueSlot AggSlot) {
281
282 for (CompoundStmt::const_body_iterator I = S.body_begin(),
283 E = S.body_end()-GetLast; I != E; ++I)
284 EmitStmt(*I);
285
286 llvm::Value *RetAlloca = nullptr;
287 if (GetLast) {
288 // We have to special case labels here. They are statements, but when put
289 // at the end of a statement expression, they yield the value of their
290 // subexpression. Handle this by walking through all labels we encounter,
291 // emitting them before we evaluate the subexpr.
292 const Stmt *LastStmt = S.body_back();
293 while (const LabelStmt *LS = dyn_cast<LabelStmt>(LastStmt)) {
294 EmitLabel(LS->getDecl());
295 LastStmt = LS->getSubStmt();
296 }
297
298 EnsureInsertPoint();
299
300 QualType ExprTy = cast<Expr>(LastStmt)->getType();
301 if (hasAggregateEvaluationKind(ExprTy)) {
302 EmitAggExpr(cast<Expr>(LastStmt), AggSlot);
303 } else {
304 // We can't return an RValue here because there might be cleanups at
305 // the end of the StmtExpr. Because of that, we have to emit the result
306 // here into a temporary alloca.
307 RetAlloca = CreateMemTemp(ExprTy);
308 EmitAnyExprToMem(cast<Expr>(LastStmt), RetAlloca, Qualifiers(),
309 /*IsInit*/false);
310 }
311
312 }
313
314 return RetAlloca;
315 }
316
SimplifyForwardingBlocks(llvm::BasicBlock * BB)317 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
318 llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
319
320 // If there is a cleanup stack, then we it isn't worth trying to
321 // simplify this block (we would need to remove it from the scope map
322 // and cleanup entry).
323 if (!EHStack.empty())
324 return;
325
326 // Can only simplify direct branches.
327 if (!BI || !BI->isUnconditional())
328 return;
329
330 // Can only simplify empty blocks.
331 if (BI != BB->begin())
332 return;
333
334 BB->replaceAllUsesWith(BI->getSuccessor(0));
335 BI->eraseFromParent();
336 BB->eraseFromParent();
337 }
338
EmitBlock(llvm::BasicBlock * BB,bool IsFinished)339 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
340 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
341
342 // Fall out of the current block (if necessary).
343 EmitBranch(BB);
344
345 if (IsFinished && BB->use_empty()) {
346 delete BB;
347 return;
348 }
349
350 // Place the block after the current block, if possible, or else at
351 // the end of the function.
352 if (CurBB && CurBB->getParent())
353 CurFn->getBasicBlockList().insertAfter(CurBB, BB);
354 else
355 CurFn->getBasicBlockList().push_back(BB);
356 Builder.SetInsertPoint(BB);
357 }
358
EmitBranch(llvm::BasicBlock * Target)359 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
360 // Emit a branch from the current block to the target one if this
361 // was a real block. If this was just a fall-through block after a
362 // terminator, don't emit it.
363 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
364
365 if (!CurBB || CurBB->getTerminator()) {
366 // If there is no insert point or the previous block is already
367 // terminated, don't touch it.
368 } else {
369 // Otherwise, create a fall-through branch.
370 Builder.CreateBr(Target);
371 }
372
373 Builder.ClearInsertionPoint();
374 }
375
EmitBlockAfterUses(llvm::BasicBlock * block)376 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
377 bool inserted = false;
378 for (llvm::User *u : block->users()) {
379 if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
380 CurFn->getBasicBlockList().insertAfter(insn->getParent(), block);
381 inserted = true;
382 break;
383 }
384 }
385
386 if (!inserted)
387 CurFn->getBasicBlockList().push_back(block);
388
389 Builder.SetInsertPoint(block);
390 }
391
392 CodeGenFunction::JumpDest
getJumpDestForLabel(const LabelDecl * D)393 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
394 JumpDest &Dest = LabelMap[D];
395 if (Dest.isValid()) return Dest;
396
397 // Create, but don't insert, the new block.
398 Dest = JumpDest(createBasicBlock(D->getName()),
399 EHScopeStack::stable_iterator::invalid(),
400 NextCleanupDestIndex++);
401 return Dest;
402 }
403
EmitLabel(const LabelDecl * D)404 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
405 // Add this label to the current lexical scope if we're within any
406 // normal cleanups. Jumps "in" to this label --- when permitted by
407 // the language --- may need to be routed around such cleanups.
408 if (EHStack.hasNormalCleanups() && CurLexicalScope)
409 CurLexicalScope->addLabel(D);
410
411 JumpDest &Dest = LabelMap[D];
412
413 // If we didn't need a forward reference to this label, just go
414 // ahead and create a destination at the current scope.
415 if (!Dest.isValid()) {
416 Dest = getJumpDestInCurrentScope(D->getName());
417
418 // Otherwise, we need to give this label a target depth and remove
419 // it from the branch-fixups list.
420 } else {
421 assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
422 Dest.setScopeDepth(EHStack.stable_begin());
423 ResolveBranchFixups(Dest.getBlock());
424 }
425
426 RegionCounter Cnt = getPGORegionCounter(D->getStmt());
427 EmitBlock(Dest.getBlock());
428 Cnt.beginRegion(Builder);
429 }
430
431 /// Change the cleanup scope of the labels in this lexical scope to
432 /// match the scope of the enclosing context.
rescopeLabels()433 void CodeGenFunction::LexicalScope::rescopeLabels() {
434 assert(!Labels.empty());
435 EHScopeStack::stable_iterator innermostScope
436 = CGF.EHStack.getInnermostNormalCleanup();
437
438 // Change the scope depth of all the labels.
439 for (SmallVectorImpl<const LabelDecl*>::const_iterator
440 i = Labels.begin(), e = Labels.end(); i != e; ++i) {
441 assert(CGF.LabelMap.count(*i));
442 JumpDest &dest = CGF.LabelMap.find(*i)->second;
443 assert(dest.getScopeDepth().isValid());
444 assert(innermostScope.encloses(dest.getScopeDepth()));
445 dest.setScopeDepth(innermostScope);
446 }
447
448 // Reparent the labels if the new scope also has cleanups.
449 if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
450 ParentScope->Labels.append(Labels.begin(), Labels.end());
451 }
452 }
453
454
EmitLabelStmt(const LabelStmt & S)455 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
456 EmitLabel(S.getDecl());
457 EmitStmt(S.getSubStmt());
458 }
459
EmitAttributedStmt(const AttributedStmt & S)460 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
461 const Stmt *SubStmt = S.getSubStmt();
462 switch (SubStmt->getStmtClass()) {
463 case Stmt::DoStmtClass:
464 EmitDoStmt(cast<DoStmt>(*SubStmt), S.getAttrs());
465 break;
466 case Stmt::ForStmtClass:
467 EmitForStmt(cast<ForStmt>(*SubStmt), S.getAttrs());
468 break;
469 case Stmt::WhileStmtClass:
470 EmitWhileStmt(cast<WhileStmt>(*SubStmt), S.getAttrs());
471 break;
472 case Stmt::CXXForRangeStmtClass:
473 EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*SubStmt), S.getAttrs());
474 break;
475 default:
476 EmitStmt(SubStmt);
477 }
478 }
479
EmitGotoStmt(const GotoStmt & S)480 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
481 // If this code is reachable then emit a stop point (if generating
482 // debug info). We have to do this ourselves because we are on the
483 // "simple" statement path.
484 if (HaveInsertPoint())
485 EmitStopPoint(&S);
486
487 EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
488 }
489
490
EmitIndirectGotoStmt(const IndirectGotoStmt & S)491 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
492 if (const LabelDecl *Target = S.getConstantTarget()) {
493 EmitBranchThroughCleanup(getJumpDestForLabel(Target));
494 return;
495 }
496
497 // Ensure that we have an i8* for our PHI node.
498 llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
499 Int8PtrTy, "addr");
500 llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
501
502 // Get the basic block for the indirect goto.
503 llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
504
505 // The first instruction in the block has to be the PHI for the switch dest,
506 // add an entry for this branch.
507 cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
508
509 EmitBranch(IndGotoBB);
510 }
511
EmitIfStmt(const IfStmt & S)512 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
513 // C99 6.8.4.1: The first substatement is executed if the expression compares
514 // unequal to 0. The condition must be a scalar type.
515 LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
516 RegionCounter Cnt = getPGORegionCounter(&S);
517
518 if (S.getConditionVariable())
519 EmitAutoVarDecl(*S.getConditionVariable());
520
521 // If the condition constant folds and can be elided, try to avoid emitting
522 // the condition and the dead arm of the if/else.
523 bool CondConstant;
524 if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant)) {
525 // Figure out which block (then or else) is executed.
526 const Stmt *Executed = S.getThen();
527 const Stmt *Skipped = S.getElse();
528 if (!CondConstant) // Condition false?
529 std::swap(Executed, Skipped);
530
531 // If the skipped block has no labels in it, just emit the executed block.
532 // This avoids emitting dead code and simplifies the CFG substantially.
533 if (!ContainsLabel(Skipped)) {
534 if (CondConstant)
535 Cnt.beginRegion(Builder);
536 if (Executed) {
537 RunCleanupsScope ExecutedScope(*this);
538 EmitStmt(Executed);
539 }
540 return;
541 }
542 }
543
544 // Otherwise, the condition did not fold, or we couldn't elide it. Just emit
545 // the conditional branch.
546 llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
547 llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
548 llvm::BasicBlock *ElseBlock = ContBlock;
549 if (S.getElse())
550 ElseBlock = createBasicBlock("if.else");
551
552 EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, Cnt.getCount());
553
554 // Emit the 'then' code.
555 EmitBlock(ThenBlock);
556 Cnt.beginRegion(Builder);
557 {
558 RunCleanupsScope ThenScope(*this);
559 EmitStmt(S.getThen());
560 }
561 EmitBranch(ContBlock);
562
563 // Emit the 'else' code if present.
564 if (const Stmt *Else = S.getElse()) {
565 {
566 // There is no need to emit line number for an unconditional branch.
567 auto NL = ApplyDebugLocation::CreateEmpty(*this);
568 EmitBlock(ElseBlock);
569 }
570 {
571 RunCleanupsScope ElseScope(*this);
572 EmitStmt(Else);
573 }
574 {
575 // There is no need to emit line number for an unconditional branch.
576 auto NL = ApplyDebugLocation::CreateEmpty(*this);
577 EmitBranch(ContBlock);
578 }
579 }
580
581 // Emit the continuation block for code after the if.
582 EmitBlock(ContBlock, true);
583 }
584
EmitCondBrHints(llvm::LLVMContext & Context,llvm::BranchInst * CondBr,ArrayRef<const Attr * > Attrs)585 void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
586 llvm::BranchInst *CondBr,
587 ArrayRef<const Attr *> Attrs) {
588 // Return if there are no hints.
589 if (Attrs.empty())
590 return;
591
592 // Add vectorize and unroll hints to the metadata on the conditional branch.
593 //
594 // FIXME: Should this really start with a size of 1?
595 SmallVector<llvm::Metadata *, 2> Metadata(1);
596 for (const auto *Attr : Attrs) {
597 const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(Attr);
598
599 // Skip non loop hint attributes
600 if (!LH)
601 continue;
602
603 LoopHintAttr::OptionType Option = LH->getOption();
604 LoopHintAttr::LoopHintState State = LH->getState();
605 const char *MetadataName;
606 switch (Option) {
607 case LoopHintAttr::Vectorize:
608 case LoopHintAttr::VectorizeWidth:
609 MetadataName = "llvm.loop.vectorize.width";
610 break;
611 case LoopHintAttr::Interleave:
612 case LoopHintAttr::InterleaveCount:
613 MetadataName = "llvm.loop.interleave.count";
614 break;
615 case LoopHintAttr::Unroll:
616 // With the unroll loop hint, a non-zero value indicates full unrolling.
617 MetadataName = State == LoopHintAttr::Disable ? "llvm.loop.unroll.disable"
618 : "llvm.loop.unroll.full";
619 break;
620 case LoopHintAttr::UnrollCount:
621 MetadataName = "llvm.loop.unroll.count";
622 break;
623 }
624
625 Expr *ValueExpr = LH->getValue();
626 int ValueInt = 1;
627 if (ValueExpr) {
628 llvm::APSInt ValueAPS =
629 ValueExpr->EvaluateKnownConstInt(CGM.getContext());
630 ValueInt = static_cast<int>(ValueAPS.getSExtValue());
631 }
632
633 llvm::Constant *Value;
634 llvm::MDString *Name;
635 switch (Option) {
636 case LoopHintAttr::Vectorize:
637 case LoopHintAttr::Interleave:
638 if (State != LoopHintAttr::Disable) {
639 // FIXME: In the future I will modifiy the behavior of the metadata
640 // so we can enable/disable vectorization and interleaving separately.
641 Name = llvm::MDString::get(Context, "llvm.loop.vectorize.enable");
642 Value = Builder.getTrue();
643 break;
644 }
645 // Vectorization/interleaving is disabled, set width/count to 1.
646 ValueInt = 1;
647 // Fallthrough.
648 case LoopHintAttr::VectorizeWidth:
649 case LoopHintAttr::InterleaveCount:
650 case LoopHintAttr::UnrollCount:
651 Name = llvm::MDString::get(Context, MetadataName);
652 Value = llvm::ConstantInt::get(Int32Ty, ValueInt);
653 break;
654 case LoopHintAttr::Unroll:
655 Name = llvm::MDString::get(Context, MetadataName);
656 Value = nullptr;
657 break;
658 }
659
660 SmallVector<llvm::Metadata *, 2> OpValues;
661 OpValues.push_back(Name);
662 if (Value)
663 OpValues.push_back(llvm::ConstantAsMetadata::get(Value));
664
665 // Set or overwrite metadata indicated by Name.
666 Metadata.push_back(llvm::MDNode::get(Context, OpValues));
667 }
668
669 // FIXME: This condition is never false. Should it be an assert?
670 if (!Metadata.empty()) {
671 // Add llvm.loop MDNode to CondBr.
672 llvm::MDNode *LoopID = llvm::MDNode::get(Context, Metadata);
673 LoopID->replaceOperandWith(0, LoopID); // First op points to itself.
674
675 CondBr->setMetadata("llvm.loop", LoopID);
676 }
677 }
678
EmitWhileStmt(const WhileStmt & S,ArrayRef<const Attr * > WhileAttrs)679 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
680 ArrayRef<const Attr *> WhileAttrs) {
681 RegionCounter Cnt = getPGORegionCounter(&S);
682
683 // Emit the header for the loop, which will also become
684 // the continue target.
685 JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
686 EmitBlock(LoopHeader.getBlock());
687
688 LoopStack.push(LoopHeader.getBlock());
689
690 // Create an exit block for when the condition fails, which will
691 // also become the break target.
692 JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
693
694 // Store the blocks to use for break and continue.
695 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
696
697 // C++ [stmt.while]p2:
698 // When the condition of a while statement is a declaration, the
699 // scope of the variable that is declared extends from its point
700 // of declaration (3.3.2) to the end of the while statement.
701 // [...]
702 // The object created in a condition is destroyed and created
703 // with each iteration of the loop.
704 RunCleanupsScope ConditionScope(*this);
705
706 if (S.getConditionVariable())
707 EmitAutoVarDecl(*S.getConditionVariable());
708
709 // Evaluate the conditional in the while header. C99 6.8.5.1: The
710 // evaluation of the controlling expression takes place before each
711 // execution of the loop body.
712 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
713
714 // while(1) is common, avoid extra exit blocks. Be sure
715 // to correctly handle break/continue though.
716 bool EmitBoolCondBranch = true;
717 if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
718 if (C->isOne())
719 EmitBoolCondBranch = false;
720
721 // As long as the condition is true, go to the loop body.
722 llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
723 if (EmitBoolCondBranch) {
724 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
725 if (ConditionScope.requiresCleanups())
726 ExitBlock = createBasicBlock("while.exit");
727 llvm::BranchInst *CondBr =
728 Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock,
729 PGO.createLoopWeights(S.getCond(), Cnt));
730
731 if (ExitBlock != LoopExit.getBlock()) {
732 EmitBlock(ExitBlock);
733 EmitBranchThroughCleanup(LoopExit);
734 }
735
736 // Attach metadata to loop body conditional branch.
737 EmitCondBrHints(LoopBody->getContext(), CondBr, WhileAttrs);
738 }
739
740 // Emit the loop body. We have to emit this in a cleanup scope
741 // because it might be a singleton DeclStmt.
742 {
743 RunCleanupsScope BodyScope(*this);
744 EmitBlock(LoopBody);
745 Cnt.beginRegion(Builder);
746 EmitStmt(S.getBody());
747 }
748
749 BreakContinueStack.pop_back();
750
751 // Immediately force cleanup.
752 ConditionScope.ForceCleanup();
753
754 EmitStopPoint(&S);
755 // Branch to the loop header again.
756 EmitBranch(LoopHeader.getBlock());
757
758 LoopStack.pop();
759
760 // Emit the exit block.
761 EmitBlock(LoopExit.getBlock(), true);
762
763 // The LoopHeader typically is just a branch if we skipped emitting
764 // a branch, try to erase it.
765 if (!EmitBoolCondBranch)
766 SimplifyForwardingBlocks(LoopHeader.getBlock());
767 }
768
EmitDoStmt(const DoStmt & S,ArrayRef<const Attr * > DoAttrs)769 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
770 ArrayRef<const Attr *> DoAttrs) {
771 JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
772 JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
773
774 RegionCounter Cnt = getPGORegionCounter(&S);
775
776 // Store the blocks to use for break and continue.
777 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
778
779 // Emit the body of the loop.
780 llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
781
782 LoopStack.push(LoopBody);
783
784 EmitBlockWithFallThrough(LoopBody, Cnt);
785 {
786 RunCleanupsScope BodyScope(*this);
787 EmitStmt(S.getBody());
788 }
789
790 EmitBlock(LoopCond.getBlock());
791
792 // C99 6.8.5.2: "The evaluation of the controlling expression takes place
793 // after each execution of the loop body."
794
795 // Evaluate the conditional in the while header.
796 // C99 6.8.5p2/p4: The first substatement is executed if the expression
797 // compares unequal to 0. The condition must be a scalar type.
798 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
799
800 BreakContinueStack.pop_back();
801
802 // "do {} while (0)" is common in macros, avoid extra blocks. Be sure
803 // to correctly handle break/continue though.
804 bool EmitBoolCondBranch = true;
805 if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
806 if (C->isZero())
807 EmitBoolCondBranch = false;
808
809 // As long as the condition is true, iterate the loop.
810 if (EmitBoolCondBranch) {
811 llvm::BranchInst *CondBr =
812 Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock(),
813 PGO.createLoopWeights(S.getCond(), Cnt));
814
815 // Attach metadata to loop body conditional branch.
816 EmitCondBrHints(LoopBody->getContext(), CondBr, DoAttrs);
817 }
818
819 LoopStack.pop();
820
821 // Emit the exit block.
822 EmitBlock(LoopExit.getBlock());
823
824 // The DoCond block typically is just a branch if we skipped
825 // emitting a branch, try to erase it.
826 if (!EmitBoolCondBranch)
827 SimplifyForwardingBlocks(LoopCond.getBlock());
828 }
829
EmitForStmt(const ForStmt & S,ArrayRef<const Attr * > ForAttrs)830 void CodeGenFunction::EmitForStmt(const ForStmt &S,
831 ArrayRef<const Attr *> ForAttrs) {
832 JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
833
834 LexicalScope ForScope(*this, S.getSourceRange());
835
836 // Evaluate the first part before the loop.
837 if (S.getInit())
838 EmitStmt(S.getInit());
839
840 RegionCounter Cnt = getPGORegionCounter(&S);
841
842 // Start the loop with a block that tests the condition.
843 // If there's an increment, the continue scope will be overwritten
844 // later.
845 JumpDest Continue = getJumpDestInCurrentScope("for.cond");
846 llvm::BasicBlock *CondBlock = Continue.getBlock();
847 EmitBlock(CondBlock);
848
849 LoopStack.push(CondBlock);
850
851 // If the for loop doesn't have an increment we can just use the
852 // condition as the continue block. Otherwise we'll need to create
853 // a block for it (in the current scope, i.e. in the scope of the
854 // condition), and that we will become our continue block.
855 if (S.getInc())
856 Continue = getJumpDestInCurrentScope("for.inc");
857
858 // Store the blocks to use for break and continue.
859 BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
860
861 // Create a cleanup scope for the condition variable cleanups.
862 LexicalScope ConditionScope(*this, S.getSourceRange());
863
864 if (S.getCond()) {
865 // If the for statement has a condition scope, emit the local variable
866 // declaration.
867 if (S.getConditionVariable()) {
868 EmitAutoVarDecl(*S.getConditionVariable());
869 }
870
871 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
872 // If there are any cleanups between here and the loop-exit scope,
873 // create a block to stage a loop exit along.
874 if (ForScope.requiresCleanups())
875 ExitBlock = createBasicBlock("for.cond.cleanup");
876
877 // As long as the condition is true, iterate the loop.
878 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
879
880 // C99 6.8.5p2/p4: The first substatement is executed if the expression
881 // compares unequal to 0. The condition must be a scalar type.
882 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
883 llvm::BranchInst *CondBr =
884 Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock,
885 PGO.createLoopWeights(S.getCond(), Cnt));
886
887 // Attach metadata to loop body conditional branch.
888 EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs);
889
890 if (ExitBlock != LoopExit.getBlock()) {
891 EmitBlock(ExitBlock);
892 EmitBranchThroughCleanup(LoopExit);
893 }
894
895 EmitBlock(ForBody);
896 } else {
897 // Treat it as a non-zero constant. Don't even create a new block for the
898 // body, just fall into it.
899 }
900 Cnt.beginRegion(Builder);
901
902 {
903 // Create a separate cleanup scope for the body, in case it is not
904 // a compound statement.
905 RunCleanupsScope BodyScope(*this);
906 EmitStmt(S.getBody());
907 }
908
909 // If there is an increment, emit it next.
910 if (S.getInc()) {
911 EmitBlock(Continue.getBlock());
912 EmitStmt(S.getInc());
913 }
914
915 BreakContinueStack.pop_back();
916
917 ConditionScope.ForceCleanup();
918
919 EmitStopPoint(&S);
920 EmitBranch(CondBlock);
921
922 ForScope.ForceCleanup();
923
924 LoopStack.pop();
925
926 // Emit the fall-through block.
927 EmitBlock(LoopExit.getBlock(), true);
928 }
929
930 void
EmitCXXForRangeStmt(const CXXForRangeStmt & S,ArrayRef<const Attr * > ForAttrs)931 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
932 ArrayRef<const Attr *> ForAttrs) {
933 JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
934
935 LexicalScope ForScope(*this, S.getSourceRange());
936
937 // Evaluate the first pieces before the loop.
938 EmitStmt(S.getRangeStmt());
939 EmitStmt(S.getBeginEndStmt());
940
941 RegionCounter Cnt = getPGORegionCounter(&S);
942
943 // Start the loop with a block that tests the condition.
944 // If there's an increment, the continue scope will be overwritten
945 // later.
946 llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
947 EmitBlock(CondBlock);
948
949 LoopStack.push(CondBlock);
950
951 // If there are any cleanups between here and the loop-exit scope,
952 // create a block to stage a loop exit along.
953 llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
954 if (ForScope.requiresCleanups())
955 ExitBlock = createBasicBlock("for.cond.cleanup");
956
957 // The loop body, consisting of the specified body and the loop variable.
958 llvm::BasicBlock *ForBody = createBasicBlock("for.body");
959
960 // The body is executed if the expression, contextually converted
961 // to bool, is true.
962 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
963 llvm::BranchInst *CondBr = Builder.CreateCondBr(
964 BoolCondVal, ForBody, ExitBlock, PGO.createLoopWeights(S.getCond(), Cnt));
965
966 // Attach metadata to loop body conditional branch.
967 EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs);
968
969 if (ExitBlock != LoopExit.getBlock()) {
970 EmitBlock(ExitBlock);
971 EmitBranchThroughCleanup(LoopExit);
972 }
973
974 EmitBlock(ForBody);
975 Cnt.beginRegion(Builder);
976
977 // Create a block for the increment. In case of a 'continue', we jump there.
978 JumpDest Continue = getJumpDestInCurrentScope("for.inc");
979
980 // Store the blocks to use for break and continue.
981 BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
982
983 {
984 // Create a separate cleanup scope for the loop variable and body.
985 LexicalScope BodyScope(*this, S.getSourceRange());
986 EmitStmt(S.getLoopVarStmt());
987 EmitStmt(S.getBody());
988 }
989
990 EmitStopPoint(&S);
991 // If there is an increment, emit it next.
992 EmitBlock(Continue.getBlock());
993 EmitStmt(S.getInc());
994
995 BreakContinueStack.pop_back();
996
997 EmitBranch(CondBlock);
998
999 ForScope.ForceCleanup();
1000
1001 LoopStack.pop();
1002
1003 // Emit the fall-through block.
1004 EmitBlock(LoopExit.getBlock(), true);
1005 }
1006
EmitReturnOfRValue(RValue RV,QualType Ty)1007 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1008 if (RV.isScalar()) {
1009 Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1010 } else if (RV.isAggregate()) {
1011 EmitAggregateCopy(ReturnValue, RV.getAggregateAddr(), Ty);
1012 } else {
1013 EmitStoreOfComplex(RV.getComplexVal(),
1014 MakeNaturalAlignAddrLValue(ReturnValue, Ty),
1015 /*init*/ true);
1016 }
1017 EmitBranchThroughCleanup(ReturnBlock);
1018 }
1019
1020 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1021 /// if the function returns void, or may be missing one if the function returns
1022 /// non-void. Fun stuff :).
EmitReturnStmt(const ReturnStmt & S)1023 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1024 // Returning from an outlined SEH helper is UB, and we already warn on it.
1025 if (IsOutlinedSEHHelper) {
1026 Builder.CreateUnreachable();
1027 Builder.ClearInsertionPoint();
1028 }
1029
1030 // Emit the result value, even if unused, to evalute the side effects.
1031 const Expr *RV = S.getRetValue();
1032
1033 // Treat block literals in a return expression as if they appeared
1034 // in their own scope. This permits a small, easily-implemented
1035 // exception to our over-conservative rules about not jumping to
1036 // statements following block literals with non-trivial cleanups.
1037 RunCleanupsScope cleanupScope(*this);
1038 if (const ExprWithCleanups *cleanups =
1039 dyn_cast_or_null<ExprWithCleanups>(RV)) {
1040 enterFullExpression(cleanups);
1041 RV = cleanups->getSubExpr();
1042 }
1043
1044 // FIXME: Clean this up by using an LValue for ReturnTemp,
1045 // EmitStoreThroughLValue, and EmitAnyExpr.
1046 if (getLangOpts().ElideConstructors &&
1047 S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable()) {
1048 // Apply the named return value optimization for this return statement,
1049 // which means doing nothing: the appropriate result has already been
1050 // constructed into the NRVO variable.
1051
1052 // If there is an NRVO flag for this variable, set it to 1 into indicate
1053 // that the cleanup code should not destroy the variable.
1054 if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1055 Builder.CreateStore(Builder.getTrue(), NRVOFlag);
1056 } else if (!ReturnValue || (RV && RV->getType()->isVoidType())) {
1057 // Make sure not to return anything, but evaluate the expression
1058 // for side effects.
1059 if (RV)
1060 EmitAnyExpr(RV);
1061 } else if (!RV) {
1062 // Do nothing (return value is left uninitialized)
1063 } else if (FnRetTy->isReferenceType()) {
1064 // If this function returns a reference, take the address of the expression
1065 // rather than the value.
1066 RValue Result = EmitReferenceBindingToExpr(RV);
1067 Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1068 } else {
1069 switch (getEvaluationKind(RV->getType())) {
1070 case TEK_Scalar:
1071 Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1072 break;
1073 case TEK_Complex:
1074 EmitComplexExprIntoLValue(RV,
1075 MakeNaturalAlignAddrLValue(ReturnValue, RV->getType()),
1076 /*isInit*/ true);
1077 break;
1078 case TEK_Aggregate: {
1079 CharUnits Alignment = getContext().getTypeAlignInChars(RV->getType());
1080 EmitAggExpr(RV, AggValueSlot::forAddr(ReturnValue, Alignment,
1081 Qualifiers(),
1082 AggValueSlot::IsDestructed,
1083 AggValueSlot::DoesNotNeedGCBarriers,
1084 AggValueSlot::IsNotAliased));
1085 break;
1086 }
1087 }
1088 }
1089
1090 ++NumReturnExprs;
1091 if (!RV || RV->isEvaluatable(getContext()))
1092 ++NumSimpleReturnExprs;
1093
1094 cleanupScope.ForceCleanup();
1095 EmitBranchThroughCleanup(ReturnBlock);
1096 }
1097
EmitDeclStmt(const DeclStmt & S)1098 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1099 // As long as debug info is modeled with instructions, we have to ensure we
1100 // have a place to insert here and write the stop point here.
1101 if (HaveInsertPoint())
1102 EmitStopPoint(&S);
1103
1104 for (const auto *I : S.decls())
1105 EmitDecl(*I);
1106 }
1107
EmitBreakStmt(const BreakStmt & S)1108 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1109 assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1110
1111 // If this code is reachable then emit a stop point (if generating
1112 // debug info). We have to do this ourselves because we are on the
1113 // "simple" statement path.
1114 if (HaveInsertPoint())
1115 EmitStopPoint(&S);
1116
1117 EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1118 }
1119
EmitContinueStmt(const ContinueStmt & S)1120 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1121 assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1122
1123 // If this code is reachable then emit a stop point (if generating
1124 // debug info). We have to do this ourselves because we are on the
1125 // "simple" statement path.
1126 if (HaveInsertPoint())
1127 EmitStopPoint(&S);
1128
1129 EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1130 }
1131
1132 /// EmitCaseStmtRange - If case statement range is not too big then
1133 /// add multiple cases to switch instruction, one for each value within
1134 /// the range. If range is too big then emit "if" condition check.
EmitCaseStmtRange(const CaseStmt & S)1135 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) {
1136 assert(S.getRHS() && "Expected RHS value in CaseStmt");
1137
1138 llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1139 llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1140
1141 RegionCounter CaseCnt = getPGORegionCounter(&S);
1142
1143 // Emit the code for this case. We do this first to make sure it is
1144 // properly chained from our predecessor before generating the
1145 // switch machinery to enter this block.
1146 llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1147 EmitBlockWithFallThrough(CaseDest, CaseCnt);
1148 EmitStmt(S.getSubStmt());
1149
1150 // If range is empty, do nothing.
1151 if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1152 return;
1153
1154 llvm::APInt Range = RHS - LHS;
1155 // FIXME: parameters such as this should not be hardcoded.
1156 if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1157 // Range is small enough to add multiple switch instruction cases.
1158 uint64_t Total = CaseCnt.getCount();
1159 unsigned NCases = Range.getZExtValue() + 1;
1160 // We only have one region counter for the entire set of cases here, so we
1161 // need to divide the weights evenly between the generated cases, ensuring
1162 // that the total weight is preserved. E.g., a weight of 5 over three cases
1163 // will be distributed as weights of 2, 2, and 1.
1164 uint64_t Weight = Total / NCases, Rem = Total % NCases;
1165 for (unsigned I = 0; I != NCases; ++I) {
1166 if (SwitchWeights)
1167 SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1168 if (Rem)
1169 Rem--;
1170 SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1171 LHS++;
1172 }
1173 return;
1174 }
1175
1176 // The range is too big. Emit "if" condition into a new block,
1177 // making sure to save and restore the current insertion point.
1178 llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1179
1180 // Push this test onto the chain of range checks (which terminates
1181 // in the default basic block). The switch's default will be changed
1182 // to the top of this chain after switch emission is complete.
1183 llvm::BasicBlock *FalseDest = CaseRangeBlock;
1184 CaseRangeBlock = createBasicBlock("sw.caserange");
1185
1186 CurFn->getBasicBlockList().push_back(CaseRangeBlock);
1187 Builder.SetInsertPoint(CaseRangeBlock);
1188
1189 // Emit range check.
1190 llvm::Value *Diff =
1191 Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1192 llvm::Value *Cond =
1193 Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1194
1195 llvm::MDNode *Weights = nullptr;
1196 if (SwitchWeights) {
1197 uint64_t ThisCount = CaseCnt.getCount();
1198 uint64_t DefaultCount = (*SwitchWeights)[0];
1199 Weights = PGO.createBranchWeights(ThisCount, DefaultCount);
1200
1201 // Since we're chaining the switch default through each large case range, we
1202 // need to update the weight for the default, ie, the first case, to include
1203 // this case.
1204 (*SwitchWeights)[0] += ThisCount;
1205 }
1206 Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1207
1208 // Restore the appropriate insertion point.
1209 if (RestoreBB)
1210 Builder.SetInsertPoint(RestoreBB);
1211 else
1212 Builder.ClearInsertionPoint();
1213 }
1214
EmitCaseStmt(const CaseStmt & S)1215 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) {
1216 // If there is no enclosing switch instance that we're aware of, then this
1217 // case statement and its block can be elided. This situation only happens
1218 // when we've constant-folded the switch, are emitting the constant case,
1219 // and part of the constant case includes another case statement. For
1220 // instance: switch (4) { case 4: do { case 5: } while (1); }
1221 if (!SwitchInsn) {
1222 EmitStmt(S.getSubStmt());
1223 return;
1224 }
1225
1226 // Handle case ranges.
1227 if (S.getRHS()) {
1228 EmitCaseStmtRange(S);
1229 return;
1230 }
1231
1232 RegionCounter CaseCnt = getPGORegionCounter(&S);
1233 llvm::ConstantInt *CaseVal =
1234 Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1235
1236 // If the body of the case is just a 'break', try to not emit an empty block.
1237 // If we're profiling or we're not optimizing, leave the block in for better
1238 // debug and coverage analysis.
1239 if (!CGM.getCodeGenOpts().ProfileInstrGenerate &&
1240 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1241 isa<BreakStmt>(S.getSubStmt())) {
1242 JumpDest Block = BreakContinueStack.back().BreakBlock;
1243
1244 // Only do this optimization if there are no cleanups that need emitting.
1245 if (isObviouslyBranchWithoutCleanups(Block)) {
1246 if (SwitchWeights)
1247 SwitchWeights->push_back(CaseCnt.getCount());
1248 SwitchInsn->addCase(CaseVal, Block.getBlock());
1249
1250 // If there was a fallthrough into this case, make sure to redirect it to
1251 // the end of the switch as well.
1252 if (Builder.GetInsertBlock()) {
1253 Builder.CreateBr(Block.getBlock());
1254 Builder.ClearInsertionPoint();
1255 }
1256 return;
1257 }
1258 }
1259
1260 llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1261 EmitBlockWithFallThrough(CaseDest, CaseCnt);
1262 if (SwitchWeights)
1263 SwitchWeights->push_back(CaseCnt.getCount());
1264 SwitchInsn->addCase(CaseVal, CaseDest);
1265
1266 // Recursively emitting the statement is acceptable, but is not wonderful for
1267 // code where we have many case statements nested together, i.e.:
1268 // case 1:
1269 // case 2:
1270 // case 3: etc.
1271 // Handling this recursively will create a new block for each case statement
1272 // that falls through to the next case which is IR intensive. It also causes
1273 // deep recursion which can run into stack depth limitations. Handle
1274 // sequential non-range case statements specially.
1275 const CaseStmt *CurCase = &S;
1276 const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1277
1278 // Otherwise, iteratively add consecutive cases to this switch stmt.
1279 while (NextCase && NextCase->getRHS() == nullptr) {
1280 CurCase = NextCase;
1281 llvm::ConstantInt *CaseVal =
1282 Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1283
1284 CaseCnt = getPGORegionCounter(NextCase);
1285 if (SwitchWeights)
1286 SwitchWeights->push_back(CaseCnt.getCount());
1287 if (CGM.getCodeGenOpts().ProfileInstrGenerate) {
1288 CaseDest = createBasicBlock("sw.bb");
1289 EmitBlockWithFallThrough(CaseDest, CaseCnt);
1290 }
1291
1292 SwitchInsn->addCase(CaseVal, CaseDest);
1293 NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1294 }
1295
1296 // Normal default recursion for non-cases.
1297 EmitStmt(CurCase->getSubStmt());
1298 }
1299
EmitDefaultStmt(const DefaultStmt & S)1300 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) {
1301 llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1302 assert(DefaultBlock->empty() &&
1303 "EmitDefaultStmt: Default block already defined?");
1304
1305 RegionCounter Cnt = getPGORegionCounter(&S);
1306 EmitBlockWithFallThrough(DefaultBlock, Cnt);
1307
1308 EmitStmt(S.getSubStmt());
1309 }
1310
1311 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1312 /// constant value that is being switched on, see if we can dead code eliminate
1313 /// the body of the switch to a simple series of statements to emit. Basically,
1314 /// on a switch (5) we want to find these statements:
1315 /// case 5:
1316 /// printf(...); <--
1317 /// ++i; <--
1318 /// break;
1319 ///
1320 /// and add them to the ResultStmts vector. If it is unsafe to do this
1321 /// transformation (for example, one of the elided statements contains a label
1322 /// that might be jumped to), return CSFC_Failure. If we handled it and 'S'
1323 /// should include statements after it (e.g. the printf() line is a substmt of
1324 /// the case) then return CSFC_FallThrough. If we handled it and found a break
1325 /// statement, then return CSFC_Success.
1326 ///
1327 /// If Case is non-null, then we are looking for the specified case, checking
1328 /// that nothing we jump over contains labels. If Case is null, then we found
1329 /// the case and are looking for the break.
1330 ///
1331 /// If the recursive walk actually finds our Case, then we set FoundCase to
1332 /// true.
1333 ///
1334 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
CollectStatementsForCase(const Stmt * S,const SwitchCase * Case,bool & FoundCase,SmallVectorImpl<const Stmt * > & ResultStmts)1335 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1336 const SwitchCase *Case,
1337 bool &FoundCase,
1338 SmallVectorImpl<const Stmt*> &ResultStmts) {
1339 // If this is a null statement, just succeed.
1340 if (!S)
1341 return Case ? CSFC_Success : CSFC_FallThrough;
1342
1343 // If this is the switchcase (case 4: or default) that we're looking for, then
1344 // we're in business. Just add the substatement.
1345 if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1346 if (S == Case) {
1347 FoundCase = true;
1348 return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1349 ResultStmts);
1350 }
1351
1352 // Otherwise, this is some other case or default statement, just ignore it.
1353 return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1354 ResultStmts);
1355 }
1356
1357 // If we are in the live part of the code and we found our break statement,
1358 // return a success!
1359 if (!Case && isa<BreakStmt>(S))
1360 return CSFC_Success;
1361
1362 // If this is a switch statement, then it might contain the SwitchCase, the
1363 // break, or neither.
1364 if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1365 // Handle this as two cases: we might be looking for the SwitchCase (if so
1366 // the skipped statements must be skippable) or we might already have it.
1367 CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1368 if (Case) {
1369 // Keep track of whether we see a skipped declaration. The code could be
1370 // using the declaration even if it is skipped, so we can't optimize out
1371 // the decl if the kept statements might refer to it.
1372 bool HadSkippedDecl = false;
1373
1374 // If we're looking for the case, just see if we can skip each of the
1375 // substatements.
1376 for (; Case && I != E; ++I) {
1377 HadSkippedDecl |= isa<DeclStmt>(*I);
1378
1379 switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1380 case CSFC_Failure: return CSFC_Failure;
1381 case CSFC_Success:
1382 // A successful result means that either 1) that the statement doesn't
1383 // have the case and is skippable, or 2) does contain the case value
1384 // and also contains the break to exit the switch. In the later case,
1385 // we just verify the rest of the statements are elidable.
1386 if (FoundCase) {
1387 // If we found the case and skipped declarations, we can't do the
1388 // optimization.
1389 if (HadSkippedDecl)
1390 return CSFC_Failure;
1391
1392 for (++I; I != E; ++I)
1393 if (CodeGenFunction::ContainsLabel(*I, true))
1394 return CSFC_Failure;
1395 return CSFC_Success;
1396 }
1397 break;
1398 case CSFC_FallThrough:
1399 // If we have a fallthrough condition, then we must have found the
1400 // case started to include statements. Consider the rest of the
1401 // statements in the compound statement as candidates for inclusion.
1402 assert(FoundCase && "Didn't find case but returned fallthrough?");
1403 // We recursively found Case, so we're not looking for it anymore.
1404 Case = nullptr;
1405
1406 // If we found the case and skipped declarations, we can't do the
1407 // optimization.
1408 if (HadSkippedDecl)
1409 return CSFC_Failure;
1410 break;
1411 }
1412 }
1413 }
1414
1415 // If we have statements in our range, then we know that the statements are
1416 // live and need to be added to the set of statements we're tracking.
1417 for (; I != E; ++I) {
1418 switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1419 case CSFC_Failure: return CSFC_Failure;
1420 case CSFC_FallThrough:
1421 // A fallthrough result means that the statement was simple and just
1422 // included in ResultStmt, keep adding them afterwards.
1423 break;
1424 case CSFC_Success:
1425 // A successful result means that we found the break statement and
1426 // stopped statement inclusion. We just ensure that any leftover stmts
1427 // are skippable and return success ourselves.
1428 for (++I; I != E; ++I)
1429 if (CodeGenFunction::ContainsLabel(*I, true))
1430 return CSFC_Failure;
1431 return CSFC_Success;
1432 }
1433 }
1434
1435 return Case ? CSFC_Success : CSFC_FallThrough;
1436 }
1437
1438 // Okay, this is some other statement that we don't handle explicitly, like a
1439 // for statement or increment etc. If we are skipping over this statement,
1440 // just verify it doesn't have labels, which would make it invalid to elide.
1441 if (Case) {
1442 if (CodeGenFunction::ContainsLabel(S, true))
1443 return CSFC_Failure;
1444 return CSFC_Success;
1445 }
1446
1447 // Otherwise, we want to include this statement. Everything is cool with that
1448 // so long as it doesn't contain a break out of the switch we're in.
1449 if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1450
1451 // Otherwise, everything is great. Include the statement and tell the caller
1452 // that we fall through and include the next statement as well.
1453 ResultStmts.push_back(S);
1454 return CSFC_FallThrough;
1455 }
1456
1457 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1458 /// then invoke CollectStatementsForCase to find the list of statements to emit
1459 /// for a switch on constant. See the comment above CollectStatementsForCase
1460 /// for more details.
FindCaseStatementsForValue(const SwitchStmt & S,const llvm::APSInt & ConstantCondValue,SmallVectorImpl<const Stmt * > & ResultStmts,ASTContext & C,const SwitchCase * & ResultCase)1461 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1462 const llvm::APSInt &ConstantCondValue,
1463 SmallVectorImpl<const Stmt*> &ResultStmts,
1464 ASTContext &C,
1465 const SwitchCase *&ResultCase) {
1466 // First step, find the switch case that is being branched to. We can do this
1467 // efficiently by scanning the SwitchCase list.
1468 const SwitchCase *Case = S.getSwitchCaseList();
1469 const DefaultStmt *DefaultCase = nullptr;
1470
1471 for (; Case; Case = Case->getNextSwitchCase()) {
1472 // It's either a default or case. Just remember the default statement in
1473 // case we're not jumping to any numbered cases.
1474 if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1475 DefaultCase = DS;
1476 continue;
1477 }
1478
1479 // Check to see if this case is the one we're looking for.
1480 const CaseStmt *CS = cast<CaseStmt>(Case);
1481 // Don't handle case ranges yet.
1482 if (CS->getRHS()) return false;
1483
1484 // If we found our case, remember it as 'case'.
1485 if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1486 break;
1487 }
1488
1489 // If we didn't find a matching case, we use a default if it exists, or we
1490 // elide the whole switch body!
1491 if (!Case) {
1492 // It is safe to elide the body of the switch if it doesn't contain labels
1493 // etc. If it is safe, return successfully with an empty ResultStmts list.
1494 if (!DefaultCase)
1495 return !CodeGenFunction::ContainsLabel(&S);
1496 Case = DefaultCase;
1497 }
1498
1499 // Ok, we know which case is being jumped to, try to collect all the
1500 // statements that follow it. This can fail for a variety of reasons. Also,
1501 // check to see that the recursive walk actually found our case statement.
1502 // Insane cases like this can fail to find it in the recursive walk since we
1503 // don't handle every stmt kind:
1504 // switch (4) {
1505 // while (1) {
1506 // case 4: ...
1507 bool FoundCase = false;
1508 ResultCase = Case;
1509 return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1510 ResultStmts) != CSFC_Failure &&
1511 FoundCase;
1512 }
1513
EmitSwitchStmt(const SwitchStmt & S)1514 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1515 // Handle nested switch statements.
1516 llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1517 SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1518 llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1519
1520 // See if we can constant fold the condition of the switch and therefore only
1521 // emit the live case statement (if any) of the switch.
1522 llvm::APSInt ConstantCondValue;
1523 if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1524 SmallVector<const Stmt*, 4> CaseStmts;
1525 const SwitchCase *Case = nullptr;
1526 if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1527 getContext(), Case)) {
1528 if (Case) {
1529 RegionCounter CaseCnt = getPGORegionCounter(Case);
1530 CaseCnt.beginRegion(Builder);
1531 }
1532 RunCleanupsScope ExecutedScope(*this);
1533
1534 // Emit the condition variable if needed inside the entire cleanup scope
1535 // used by this special case for constant folded switches.
1536 if (S.getConditionVariable())
1537 EmitAutoVarDecl(*S.getConditionVariable());
1538
1539 // At this point, we are no longer "within" a switch instance, so
1540 // we can temporarily enforce this to ensure that any embedded case
1541 // statements are not emitted.
1542 SwitchInsn = nullptr;
1543
1544 // Okay, we can dead code eliminate everything except this case. Emit the
1545 // specified series of statements and we're good.
1546 for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1547 EmitStmt(CaseStmts[i]);
1548 RegionCounter ExitCnt = getPGORegionCounter(&S);
1549 ExitCnt.beginRegion(Builder);
1550
1551 // Now we want to restore the saved switch instance so that nested
1552 // switches continue to function properly
1553 SwitchInsn = SavedSwitchInsn;
1554
1555 return;
1556 }
1557 }
1558
1559 JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1560
1561 RunCleanupsScope ConditionScope(*this);
1562 if (S.getConditionVariable())
1563 EmitAutoVarDecl(*S.getConditionVariable());
1564 llvm::Value *CondV = EmitScalarExpr(S.getCond());
1565
1566 // Create basic block to hold stuff that comes after switch
1567 // statement. We also need to create a default block now so that
1568 // explicit case ranges tests can have a place to jump to on
1569 // failure.
1570 llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
1571 SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
1572 if (PGO.haveRegionCounts()) {
1573 // Walk the SwitchCase list to find how many there are.
1574 uint64_t DefaultCount = 0;
1575 unsigned NumCases = 0;
1576 for (const SwitchCase *Case = S.getSwitchCaseList();
1577 Case;
1578 Case = Case->getNextSwitchCase()) {
1579 if (isa<DefaultStmt>(Case))
1580 DefaultCount = getPGORegionCounter(Case).getCount();
1581 NumCases += 1;
1582 }
1583 SwitchWeights = new SmallVector<uint64_t, 16>();
1584 SwitchWeights->reserve(NumCases);
1585 // The default needs to be first. We store the edge count, so we already
1586 // know the right weight.
1587 SwitchWeights->push_back(DefaultCount);
1588 }
1589 CaseRangeBlock = DefaultBlock;
1590
1591 // Clear the insertion point to indicate we are in unreachable code.
1592 Builder.ClearInsertionPoint();
1593
1594 // All break statements jump to NextBlock. If BreakContinueStack is non-empty
1595 // then reuse last ContinueBlock.
1596 JumpDest OuterContinue;
1597 if (!BreakContinueStack.empty())
1598 OuterContinue = BreakContinueStack.back().ContinueBlock;
1599
1600 BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
1601
1602 // Emit switch body.
1603 EmitStmt(S.getBody());
1604
1605 BreakContinueStack.pop_back();
1606
1607 // Update the default block in case explicit case range tests have
1608 // been chained on top.
1609 SwitchInsn->setDefaultDest(CaseRangeBlock);
1610
1611 // If a default was never emitted:
1612 if (!DefaultBlock->getParent()) {
1613 // If we have cleanups, emit the default block so that there's a
1614 // place to jump through the cleanups from.
1615 if (ConditionScope.requiresCleanups()) {
1616 EmitBlock(DefaultBlock);
1617
1618 // Otherwise, just forward the default block to the switch end.
1619 } else {
1620 DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
1621 delete DefaultBlock;
1622 }
1623 }
1624
1625 ConditionScope.ForceCleanup();
1626
1627 // Emit continuation.
1628 EmitBlock(SwitchExit.getBlock(), true);
1629 RegionCounter ExitCnt = getPGORegionCounter(&S);
1630 ExitCnt.beginRegion(Builder);
1631
1632 if (SwitchWeights) {
1633 assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
1634 "switch weights do not match switch cases");
1635 // If there's only one jump destination there's no sense weighting it.
1636 if (SwitchWeights->size() > 1)
1637 SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
1638 PGO.createBranchWeights(*SwitchWeights));
1639 delete SwitchWeights;
1640 }
1641 SwitchInsn = SavedSwitchInsn;
1642 SwitchWeights = SavedSwitchWeights;
1643 CaseRangeBlock = SavedCRBlock;
1644 }
1645
1646 static std::string
SimplifyConstraint(const char * Constraint,const TargetInfo & Target,SmallVectorImpl<TargetInfo::ConstraintInfo> * OutCons=nullptr)1647 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
1648 SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
1649 std::string Result;
1650
1651 while (*Constraint) {
1652 switch (*Constraint) {
1653 default:
1654 Result += Target.convertConstraint(Constraint);
1655 break;
1656 // Ignore these
1657 case '*':
1658 case '?':
1659 case '!':
1660 case '=': // Will see this and the following in mult-alt constraints.
1661 case '+':
1662 break;
1663 case '#': // Ignore the rest of the constraint alternative.
1664 while (Constraint[1] && Constraint[1] != ',')
1665 Constraint++;
1666 break;
1667 case '&':
1668 case '%':
1669 Result += *Constraint;
1670 while (Constraint[1] && Constraint[1] == *Constraint)
1671 Constraint++;
1672 break;
1673 case ',':
1674 Result += "|";
1675 break;
1676 case 'g':
1677 Result += "imr";
1678 break;
1679 case '[': {
1680 assert(OutCons &&
1681 "Must pass output names to constraints with a symbolic name");
1682 unsigned Index;
1683 bool result = Target.resolveSymbolicName(Constraint,
1684 &(*OutCons)[0],
1685 OutCons->size(), Index);
1686 assert(result && "Could not resolve symbolic name"); (void)result;
1687 Result += llvm::utostr(Index);
1688 break;
1689 }
1690 }
1691
1692 Constraint++;
1693 }
1694
1695 return Result;
1696 }
1697
1698 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
1699 /// as using a particular register add that as a constraint that will be used
1700 /// in this asm stmt.
1701 static std::string
AddVariableConstraints(const std::string & Constraint,const Expr & AsmExpr,const TargetInfo & Target,CodeGenModule & CGM,const AsmStmt & Stmt,const bool EarlyClobber)1702 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
1703 const TargetInfo &Target, CodeGenModule &CGM,
1704 const AsmStmt &Stmt, const bool EarlyClobber) {
1705 const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
1706 if (!AsmDeclRef)
1707 return Constraint;
1708 const ValueDecl &Value = *AsmDeclRef->getDecl();
1709 const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
1710 if (!Variable)
1711 return Constraint;
1712 if (Variable->getStorageClass() != SC_Register)
1713 return Constraint;
1714 AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
1715 if (!Attr)
1716 return Constraint;
1717 StringRef Register = Attr->getLabel();
1718 assert(Target.isValidGCCRegisterName(Register));
1719 // We're using validateOutputConstraint here because we only care if
1720 // this is a register constraint.
1721 TargetInfo::ConstraintInfo Info(Constraint, "");
1722 if (Target.validateOutputConstraint(Info) &&
1723 !Info.allowsRegister()) {
1724 CGM.ErrorUnsupported(&Stmt, "__asm__");
1725 return Constraint;
1726 }
1727 // Canonicalize the register here before returning it.
1728 Register = Target.getNormalizedGCCRegisterName(Register);
1729 return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
1730 }
1731
1732 llvm::Value*
EmitAsmInputLValue(const TargetInfo::ConstraintInfo & Info,LValue InputValue,QualType InputType,std::string & ConstraintStr,SourceLocation Loc)1733 CodeGenFunction::EmitAsmInputLValue(const TargetInfo::ConstraintInfo &Info,
1734 LValue InputValue, QualType InputType,
1735 std::string &ConstraintStr,
1736 SourceLocation Loc) {
1737 llvm::Value *Arg;
1738 if (Info.allowsRegister() || !Info.allowsMemory()) {
1739 if (CodeGenFunction::hasScalarEvaluationKind(InputType)) {
1740 Arg = EmitLoadOfLValue(InputValue, Loc).getScalarVal();
1741 } else {
1742 llvm::Type *Ty = ConvertType(InputType);
1743 uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
1744 if (Size <= 64 && llvm::isPowerOf2_64(Size)) {
1745 Ty = llvm::IntegerType::get(getLLVMContext(), Size);
1746 Ty = llvm::PointerType::getUnqual(Ty);
1747
1748 Arg = Builder.CreateLoad(Builder.CreateBitCast(InputValue.getAddress(),
1749 Ty));
1750 } else {
1751 Arg = InputValue.getAddress();
1752 ConstraintStr += '*';
1753 }
1754 }
1755 } else {
1756 Arg = InputValue.getAddress();
1757 ConstraintStr += '*';
1758 }
1759
1760 return Arg;
1761 }
1762
EmitAsmInput(const TargetInfo::ConstraintInfo & Info,const Expr * InputExpr,std::string & ConstraintStr)1763 llvm::Value* CodeGenFunction::EmitAsmInput(
1764 const TargetInfo::ConstraintInfo &Info,
1765 const Expr *InputExpr,
1766 std::string &ConstraintStr) {
1767 if (Info.allowsRegister() || !Info.allowsMemory())
1768 if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
1769 return EmitScalarExpr(InputExpr);
1770
1771 InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
1772 LValue Dest = EmitLValue(InputExpr);
1773 return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
1774 InputExpr->getExprLoc());
1775 }
1776
1777 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
1778 /// asm call instruction. The !srcloc MDNode contains a list of constant
1779 /// integers which are the source locations of the start of each line in the
1780 /// asm.
getAsmSrcLocInfo(const StringLiteral * Str,CodeGenFunction & CGF)1781 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
1782 CodeGenFunction &CGF) {
1783 SmallVector<llvm::Metadata *, 8> Locs;
1784 // Add the location of the first line to the MDNode.
1785 Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1786 CGF.Int32Ty, Str->getLocStart().getRawEncoding())));
1787 StringRef StrVal = Str->getString();
1788 if (!StrVal.empty()) {
1789 const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
1790 const LangOptions &LangOpts = CGF.CGM.getLangOpts();
1791
1792 // Add the location of the start of each subsequent line of the asm to the
1793 // MDNode.
1794 for (unsigned i = 0, e = StrVal.size()-1; i != e; ++i) {
1795 if (StrVal[i] != '\n') continue;
1796 SourceLocation LineLoc = Str->getLocationOfByte(i+1, SM, LangOpts,
1797 CGF.getTarget());
1798 Locs.push_back(llvm::ConstantAsMetadata::get(
1799 llvm::ConstantInt::get(CGF.Int32Ty, LineLoc.getRawEncoding())));
1800 }
1801 }
1802
1803 return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
1804 }
1805
EmitAsmStmt(const AsmStmt & S)1806 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
1807 // Assemble the final asm string.
1808 std::string AsmString = S.generateAsmString(getContext());
1809
1810 // Get all the output and input constraints together.
1811 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
1812 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
1813
1814 for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
1815 StringRef Name;
1816 if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
1817 Name = GAS->getOutputName(i);
1818 TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
1819 bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
1820 assert(IsValid && "Failed to parse output constraint");
1821 OutputConstraintInfos.push_back(Info);
1822 }
1823
1824 for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
1825 StringRef Name;
1826 if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
1827 Name = GAS->getInputName(i);
1828 TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
1829 bool IsValid =
1830 getTarget().validateInputConstraint(OutputConstraintInfos.data(),
1831 S.getNumOutputs(), Info);
1832 assert(IsValid && "Failed to parse input constraint"); (void)IsValid;
1833 InputConstraintInfos.push_back(Info);
1834 }
1835
1836 std::string Constraints;
1837
1838 std::vector<LValue> ResultRegDests;
1839 std::vector<QualType> ResultRegQualTys;
1840 std::vector<llvm::Type *> ResultRegTypes;
1841 std::vector<llvm::Type *> ResultTruncRegTypes;
1842 std::vector<llvm::Type *> ArgTypes;
1843 std::vector<llvm::Value*> Args;
1844
1845 // Keep track of inout constraints.
1846 std::string InOutConstraints;
1847 std::vector<llvm::Value*> InOutArgs;
1848 std::vector<llvm::Type*> InOutArgTypes;
1849
1850 for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
1851 TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
1852
1853 // Simplify the output constraint.
1854 std::string OutputConstraint(S.getOutputConstraint(i));
1855 OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
1856 getTarget());
1857
1858 const Expr *OutExpr = S.getOutputExpr(i);
1859 OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
1860
1861 OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
1862 getTarget(), CGM, S,
1863 Info.earlyClobber());
1864
1865 LValue Dest = EmitLValue(OutExpr);
1866 if (!Constraints.empty())
1867 Constraints += ',';
1868
1869 // If this is a register output, then make the inline asm return it
1870 // by-value. If this is a memory result, return the value by-reference.
1871 if (!Info.allowsMemory() && hasScalarEvaluationKind(OutExpr->getType())) {
1872 Constraints += "=" + OutputConstraint;
1873 ResultRegQualTys.push_back(OutExpr->getType());
1874 ResultRegDests.push_back(Dest);
1875 ResultRegTypes.push_back(ConvertTypeForMem(OutExpr->getType()));
1876 ResultTruncRegTypes.push_back(ResultRegTypes.back());
1877
1878 // If this output is tied to an input, and if the input is larger, then
1879 // we need to set the actual result type of the inline asm node to be the
1880 // same as the input type.
1881 if (Info.hasMatchingInput()) {
1882 unsigned InputNo;
1883 for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
1884 TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
1885 if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
1886 break;
1887 }
1888 assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
1889
1890 QualType InputTy = S.getInputExpr(InputNo)->getType();
1891 QualType OutputType = OutExpr->getType();
1892
1893 uint64_t InputSize = getContext().getTypeSize(InputTy);
1894 if (getContext().getTypeSize(OutputType) < InputSize) {
1895 // Form the asm to return the value as a larger integer or fp type.
1896 ResultRegTypes.back() = ConvertType(InputTy);
1897 }
1898 }
1899 if (llvm::Type* AdjTy =
1900 getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
1901 ResultRegTypes.back()))
1902 ResultRegTypes.back() = AdjTy;
1903 else {
1904 CGM.getDiags().Report(S.getAsmLoc(),
1905 diag::err_asm_invalid_type_in_input)
1906 << OutExpr->getType() << OutputConstraint;
1907 }
1908 } else {
1909 ArgTypes.push_back(Dest.getAddress()->getType());
1910 Args.push_back(Dest.getAddress());
1911 Constraints += "=*";
1912 Constraints += OutputConstraint;
1913 }
1914
1915 if (Info.isReadWrite()) {
1916 InOutConstraints += ',';
1917
1918 const Expr *InputExpr = S.getOutputExpr(i);
1919 llvm::Value *Arg = EmitAsmInputLValue(Info, Dest, InputExpr->getType(),
1920 InOutConstraints,
1921 InputExpr->getExprLoc());
1922
1923 if (llvm::Type* AdjTy =
1924 getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
1925 Arg->getType()))
1926 Arg = Builder.CreateBitCast(Arg, AdjTy);
1927
1928 if (Info.allowsRegister())
1929 InOutConstraints += llvm::utostr(i);
1930 else
1931 InOutConstraints += OutputConstraint;
1932
1933 InOutArgTypes.push_back(Arg->getType());
1934 InOutArgs.push_back(Arg);
1935 }
1936 }
1937
1938 // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
1939 // to the return value slot. Only do this when returning in registers.
1940 if (isa<MSAsmStmt>(&S)) {
1941 const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
1942 if (RetAI.isDirect() || RetAI.isExtend()) {
1943 // Make a fake lvalue for the return value slot.
1944 LValue ReturnSlot = MakeAddrLValue(ReturnValue, FnRetTy);
1945 CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
1946 *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
1947 ResultRegDests, AsmString, S.getNumOutputs());
1948 SawAsmBlock = true;
1949 }
1950 }
1951
1952 for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
1953 const Expr *InputExpr = S.getInputExpr(i);
1954
1955 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
1956
1957 if (!Constraints.empty())
1958 Constraints += ',';
1959
1960 // Simplify the input constraint.
1961 std::string InputConstraint(S.getInputConstraint(i));
1962 InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
1963 &OutputConstraintInfos);
1964
1965 InputConstraint = AddVariableConstraints(
1966 InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
1967 getTarget(), CGM, S, false /* No EarlyClobber */);
1968
1969 llvm::Value *Arg = EmitAsmInput(Info, InputExpr, Constraints);
1970
1971 // If this input argument is tied to a larger output result, extend the
1972 // input to be the same size as the output. The LLVM backend wants to see
1973 // the input and output of a matching constraint be the same size. Note
1974 // that GCC does not define what the top bits are here. We use zext because
1975 // that is usually cheaper, but LLVM IR should really get an anyext someday.
1976 if (Info.hasTiedOperand()) {
1977 unsigned Output = Info.getTiedOperand();
1978 QualType OutputType = S.getOutputExpr(Output)->getType();
1979 QualType InputTy = InputExpr->getType();
1980
1981 if (getContext().getTypeSize(OutputType) >
1982 getContext().getTypeSize(InputTy)) {
1983 // Use ptrtoint as appropriate so that we can do our extension.
1984 if (isa<llvm::PointerType>(Arg->getType()))
1985 Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
1986 llvm::Type *OutputTy = ConvertType(OutputType);
1987 if (isa<llvm::IntegerType>(OutputTy))
1988 Arg = Builder.CreateZExt(Arg, OutputTy);
1989 else if (isa<llvm::PointerType>(OutputTy))
1990 Arg = Builder.CreateZExt(Arg, IntPtrTy);
1991 else {
1992 assert(OutputTy->isFloatingPointTy() && "Unexpected output type");
1993 Arg = Builder.CreateFPExt(Arg, OutputTy);
1994 }
1995 }
1996 }
1997 if (llvm::Type* AdjTy =
1998 getTargetHooks().adjustInlineAsmType(*this, InputConstraint,
1999 Arg->getType()))
2000 Arg = Builder.CreateBitCast(Arg, AdjTy);
2001 else
2002 CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2003 << InputExpr->getType() << InputConstraint;
2004
2005 ArgTypes.push_back(Arg->getType());
2006 Args.push_back(Arg);
2007 Constraints += InputConstraint;
2008 }
2009
2010 // Append the "input" part of inout constraints last.
2011 for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2012 ArgTypes.push_back(InOutArgTypes[i]);
2013 Args.push_back(InOutArgs[i]);
2014 }
2015 Constraints += InOutConstraints;
2016
2017 // Clobbers
2018 for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2019 StringRef Clobber = S.getClobber(i);
2020
2021 if (Clobber != "memory" && Clobber != "cc")
2022 Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2023
2024 if (!Constraints.empty())
2025 Constraints += ',';
2026
2027 Constraints += "~{";
2028 Constraints += Clobber;
2029 Constraints += '}';
2030 }
2031
2032 // Add machine specific clobbers
2033 std::string MachineClobbers = getTarget().getClobbers();
2034 if (!MachineClobbers.empty()) {
2035 if (!Constraints.empty())
2036 Constraints += ',';
2037 Constraints += MachineClobbers;
2038 }
2039
2040 llvm::Type *ResultType;
2041 if (ResultRegTypes.empty())
2042 ResultType = VoidTy;
2043 else if (ResultRegTypes.size() == 1)
2044 ResultType = ResultRegTypes[0];
2045 else
2046 ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2047
2048 llvm::FunctionType *FTy =
2049 llvm::FunctionType::get(ResultType, ArgTypes, false);
2050
2051 bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2052 llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2053 llvm::InlineAsm::AD_Intel : llvm::InlineAsm::AD_ATT;
2054 llvm::InlineAsm *IA =
2055 llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect,
2056 /* IsAlignStack */ false, AsmDialect);
2057 llvm::CallInst *Result = Builder.CreateCall(IA, Args);
2058 Result->addAttribute(llvm::AttributeSet::FunctionIndex,
2059 llvm::Attribute::NoUnwind);
2060
2061 // Slap the source location of the inline asm into a !srcloc metadata on the
2062 // call.
2063 if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S)) {
2064 Result->setMetadata("srcloc", getAsmSrcLocInfo(gccAsmStmt->getAsmString(),
2065 *this));
2066 } else {
2067 // At least put the line number on MS inline asm blobs.
2068 auto Loc = llvm::ConstantInt::get(Int32Ty, S.getAsmLoc().getRawEncoding());
2069 Result->setMetadata("srcloc",
2070 llvm::MDNode::get(getLLVMContext(),
2071 llvm::ConstantAsMetadata::get(Loc)));
2072 }
2073
2074 // Extract all of the register value results from the asm.
2075 std::vector<llvm::Value*> RegResults;
2076 if (ResultRegTypes.size() == 1) {
2077 RegResults.push_back(Result);
2078 } else {
2079 for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2080 llvm::Value *Tmp = Builder.CreateExtractValue(Result, i, "asmresult");
2081 RegResults.push_back(Tmp);
2082 }
2083 }
2084
2085 assert(RegResults.size() == ResultRegTypes.size());
2086 assert(RegResults.size() == ResultTruncRegTypes.size());
2087 assert(RegResults.size() == ResultRegDests.size());
2088 for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2089 llvm::Value *Tmp = RegResults[i];
2090
2091 // If the result type of the LLVM IR asm doesn't match the result type of
2092 // the expression, do the conversion.
2093 if (ResultRegTypes[i] != ResultTruncRegTypes[i]) {
2094 llvm::Type *TruncTy = ResultTruncRegTypes[i];
2095
2096 // Truncate the integer result to the right size, note that TruncTy can be
2097 // a pointer.
2098 if (TruncTy->isFloatingPointTy())
2099 Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2100 else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2101 uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2102 Tmp = Builder.CreateTrunc(Tmp,
2103 llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize));
2104 Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2105 } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2106 uint64_t TmpSize =CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2107 Tmp = Builder.CreatePtrToInt(Tmp,
2108 llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize));
2109 Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2110 } else if (TruncTy->isIntegerTy()) {
2111 Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2112 } else if (TruncTy->isVectorTy()) {
2113 Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2114 }
2115 }
2116
2117 EmitStoreThroughLValue(RValue::get(Tmp), ResultRegDests[i]);
2118 }
2119 }
2120
InitCapturedStruct(const CapturedStmt & S)2121 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2122 const RecordDecl *RD = S.getCapturedRecordDecl();
2123 QualType RecordTy = getContext().getRecordType(RD);
2124
2125 // Initialize the captured struct.
2126 LValue SlotLV = MakeNaturalAlignAddrLValue(
2127 CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2128
2129 RecordDecl::field_iterator CurField = RD->field_begin();
2130 for (CapturedStmt::capture_init_iterator I = S.capture_init_begin(),
2131 E = S.capture_init_end();
2132 I != E; ++I, ++CurField) {
2133 LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2134 if (CurField->hasCapturedVLAType()) {
2135 auto VAT = CurField->getCapturedVLAType();
2136 EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV);
2137 } else {
2138 EmitInitializerForField(*CurField, LV, *I, None);
2139 }
2140 }
2141
2142 return SlotLV;
2143 }
2144
2145 /// Generate an outlined function for the body of a CapturedStmt, store any
2146 /// captured variables into the captured struct, and call the outlined function.
2147 llvm::Function *
EmitCapturedStmt(const CapturedStmt & S,CapturedRegionKind K)2148 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2149 LValue CapStruct = InitCapturedStruct(S);
2150
2151 // Emit the CapturedDecl
2152 CodeGenFunction CGF(CGM, true);
2153 CGF.CapturedStmtInfo = new CGCapturedStmtInfo(S, K);
2154 llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2155 delete CGF.CapturedStmtInfo;
2156
2157 // Emit call to the helper function.
2158 EmitCallOrInvoke(F, CapStruct.getAddress());
2159
2160 return F;
2161 }
2162
2163 llvm::Value *
GenerateCapturedStmtArgument(const CapturedStmt & S)2164 CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2165 LValue CapStruct = InitCapturedStruct(S);
2166 return CapStruct.getAddress();
2167 }
2168
2169 /// Creates the outlined function for a CapturedStmt.
2170 llvm::Function *
GenerateCapturedStmtFunction(const CapturedStmt & S)2171 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2172 assert(CapturedStmtInfo &&
2173 "CapturedStmtInfo should be set when generating the captured function");
2174 const CapturedDecl *CD = S.getCapturedDecl();
2175 const RecordDecl *RD = S.getCapturedRecordDecl();
2176 SourceLocation Loc = S.getLocStart();
2177 assert(CD->hasBody() && "missing CapturedDecl body");
2178
2179 // Build the argument list.
2180 ASTContext &Ctx = CGM.getContext();
2181 FunctionArgList Args;
2182 Args.append(CD->param_begin(), CD->param_end());
2183
2184 // Create the function declaration.
2185 FunctionType::ExtInfo ExtInfo;
2186 const CGFunctionInfo &FuncInfo =
2187 CGM.getTypes().arrangeFreeFunctionDeclaration(Ctx.VoidTy, Args, ExtInfo,
2188 /*IsVariadic=*/false);
2189 llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2190
2191 llvm::Function *F =
2192 llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2193 CapturedStmtInfo->getHelperName(), &CGM.getModule());
2194 CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2195 if (CD->isNothrow())
2196 F->addFnAttr(llvm::Attribute::NoUnwind);
2197
2198 // Generate the function.
2199 StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args,
2200 CD->getLocation(),
2201 CD->getBody()->getLocStart());
2202 // Set the context parameter in CapturedStmtInfo.
2203 llvm::Value *DeclPtr = LocalDeclMap[CD->getContextParam()];
2204 assert(DeclPtr && "missing context parameter for CapturedStmt");
2205 CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
2206
2207 // Initialize variable-length arrays.
2208 LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
2209 Ctx.getTagDeclType(RD));
2210 for (auto *FD : RD->fields()) {
2211 if (FD->hasCapturedVLAType()) {
2212 auto *ExprArg = EmitLoadOfLValue(EmitLValueForField(Base, FD),
2213 S.getLocStart()).getScalarVal();
2214 auto VAT = FD->getCapturedVLAType();
2215 VLASizeMap[VAT->getSizeExpr()] = ExprArg;
2216 }
2217 }
2218
2219 // If 'this' is captured, load it into CXXThisValue.
2220 if (CapturedStmtInfo->isCXXThisExprCaptured()) {
2221 FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
2222 LValue ThisLValue = EmitLValueForField(Base, FD);
2223 CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
2224 }
2225
2226 PGO.assignRegionCounters(CD, F);
2227 CapturedStmtInfo->EmitBody(*this, CD->getBody());
2228 FinishFunction(CD->getBodyRBrace());
2229
2230 return F;
2231 }
2232