1//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===//
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 coordinates the per-function state used while generating code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CGCUDARuntime.h"
16#include "CGCXXABI.h"
17#include "CGDebugInfo.h"
18#include "CGOpenMPRuntime.h"
19#include "CodeGenModule.h"
20#include "CodeGenPGO.h"
21#include "TargetInfo.h"
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/Decl.h"
24#include "clang/AST/DeclCXX.h"
25#include "clang/AST/StmtCXX.h"
26#include "clang/Basic/TargetInfo.h"
27#include "clang/CodeGen/CGFunctionInfo.h"
28#include "clang/Frontend/CodeGenOptions.h"
29#include "llvm/IR/DataLayout.h"
30#include "llvm/IR/Intrinsics.h"
31#include "llvm/IR/MDBuilder.h"
32#include "llvm/IR/Operator.h"
33using namespace clang;
34using namespace CodeGen;
35
36CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
37    : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()),
38      Builder(cgm.getModule().getContext(), llvm::ConstantFolder(),
39              CGBuilderInserterTy(this)),
40      CurFn(nullptr), CapturedStmtInfo(nullptr),
41      SanOpts(CGM.getLangOpts().Sanitize), IsSanitizerScope(false),
42      CurFuncIsThunk(false), AutoreleaseResult(false), SawAsmBlock(false),
43      IsOutlinedSEHHelper(false), BlockInfo(nullptr), BlockPointer(nullptr),
44      LambdaThisCaptureField(nullptr), NormalCleanupDest(nullptr),
45      NextCleanupDestIndex(1), FirstBlockInfo(nullptr), EHResumeBlock(nullptr),
46      ExceptionSlot(nullptr), EHSelectorSlot(nullptr),
47      AbnormalTerminationSlot(nullptr), SEHPointersDecl(nullptr),
48      DebugInfo(CGM.getModuleDebugInfo()), DisableDebugInfo(false),
49      DidCallStackSave(false), IndirectBranch(nullptr), PGO(cgm),
50      SwitchInsn(nullptr), SwitchWeights(nullptr), CaseRangeBlock(nullptr),
51      UnreachableBlock(nullptr), NumReturnExprs(0), NumSimpleReturnExprs(0),
52      CXXABIThisDecl(nullptr), CXXABIThisValue(nullptr), CXXThisValue(nullptr),
53      CXXDefaultInitExprThis(nullptr), CXXStructorImplicitParamDecl(nullptr),
54      CXXStructorImplicitParamValue(nullptr), OutermostConditional(nullptr),
55      CurLexicalScope(nullptr), TerminateLandingPad(nullptr),
56      TerminateHandler(nullptr), TrapBB(nullptr) {
57  if (!suppressNewContext)
58    CGM.getCXXABI().getMangleContext().startNewFunction();
59
60  llvm::FastMathFlags FMF;
61  if (CGM.getLangOpts().FastMath)
62    FMF.setUnsafeAlgebra();
63  if (CGM.getLangOpts().FiniteMathOnly) {
64    FMF.setNoNaNs();
65    FMF.setNoInfs();
66  }
67  if (CGM.getCodeGenOpts().NoNaNsFPMath) {
68    FMF.setNoNaNs();
69  }
70  if (CGM.getCodeGenOpts().NoSignedZeros) {
71    FMF.setNoSignedZeros();
72  }
73  if (CGM.getCodeGenOpts().ReciprocalMath) {
74    FMF.setAllowReciprocal();
75  }
76  Builder.SetFastMathFlags(FMF);
77}
78
79CodeGenFunction::~CodeGenFunction() {
80  assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup");
81
82  // If there are any unclaimed block infos, go ahead and destroy them
83  // now.  This can happen if IR-gen gets clever and skips evaluating
84  // something.
85  if (FirstBlockInfo)
86    destroyBlockInfos(FirstBlockInfo);
87
88  if (getLangOpts().OpenMP) {
89    CGM.getOpenMPRuntime().functionFinished(*this);
90  }
91}
92
93LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) {
94  CharUnits Alignment;
95  if (CGM.getCXXABI().isTypeInfoCalculable(T)) {
96    Alignment = getContext().getTypeAlignInChars(T);
97    unsigned MaxAlign = getContext().getLangOpts().MaxTypeAlign;
98    if (MaxAlign && Alignment.getQuantity() > MaxAlign &&
99        !getContext().isAlignmentRequired(T))
100      Alignment = CharUnits::fromQuantity(MaxAlign);
101  }
102  return LValue::MakeAddr(V, T, Alignment, getContext(), CGM.getTBAAInfo(T));
103}
104
105llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) {
106  return CGM.getTypes().ConvertTypeForMem(T);
107}
108
109llvm::Type *CodeGenFunction::ConvertType(QualType T) {
110  return CGM.getTypes().ConvertType(T);
111}
112
113TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) {
114  type = type.getCanonicalType();
115  while (true) {
116    switch (type->getTypeClass()) {
117#define TYPE(name, parent)
118#define ABSTRACT_TYPE(name, parent)
119#define NON_CANONICAL_TYPE(name, parent) case Type::name:
120#define DEPENDENT_TYPE(name, parent) case Type::name:
121#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name:
122#include "clang/AST/TypeNodes.def"
123      llvm_unreachable("non-canonical or dependent type in IR-generation");
124
125    case Type::Auto:
126      llvm_unreachable("undeduced auto type in IR-generation");
127
128    // Various scalar types.
129    case Type::Builtin:
130    case Type::Pointer:
131    case Type::BlockPointer:
132    case Type::LValueReference:
133    case Type::RValueReference:
134    case Type::MemberPointer:
135    case Type::Vector:
136    case Type::ExtVector:
137    case Type::FunctionProto:
138    case Type::FunctionNoProto:
139    case Type::Enum:
140    case Type::ObjCObjectPointer:
141      return TEK_Scalar;
142
143    // Complexes.
144    case Type::Complex:
145      return TEK_Complex;
146
147    // Arrays, records, and Objective-C objects.
148    case Type::ConstantArray:
149    case Type::IncompleteArray:
150    case Type::VariableArray:
151    case Type::Record:
152    case Type::ObjCObject:
153    case Type::ObjCInterface:
154      return TEK_Aggregate;
155
156    // We operate on atomic values according to their underlying type.
157    case Type::Atomic:
158      type = cast<AtomicType>(type)->getValueType();
159      continue;
160    }
161    llvm_unreachable("unknown type kind!");
162  }
163}
164
165llvm::DebugLoc CodeGenFunction::EmitReturnBlock() {
166  // For cleanliness, we try to avoid emitting the return block for
167  // simple cases.
168  llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
169
170  if (CurBB) {
171    assert(!CurBB->getTerminator() && "Unexpected terminated block.");
172
173    // We have a valid insert point, reuse it if it is empty or there are no
174    // explicit jumps to the return block.
175    if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) {
176      ReturnBlock.getBlock()->replaceAllUsesWith(CurBB);
177      delete ReturnBlock.getBlock();
178    } else
179      EmitBlock(ReturnBlock.getBlock());
180    return llvm::DebugLoc();
181  }
182
183  // Otherwise, if the return block is the target of a single direct
184  // branch then we can just put the code in that block instead. This
185  // cleans up functions which started with a unified return block.
186  if (ReturnBlock.getBlock()->hasOneUse()) {
187    llvm::BranchInst *BI =
188      dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->user_begin());
189    if (BI && BI->isUnconditional() &&
190        BI->getSuccessor(0) == ReturnBlock.getBlock()) {
191      // Record/return the DebugLoc of the simple 'return' expression to be used
192      // later by the actual 'ret' instruction.
193      llvm::DebugLoc Loc = BI->getDebugLoc();
194      Builder.SetInsertPoint(BI->getParent());
195      BI->eraseFromParent();
196      delete ReturnBlock.getBlock();
197      return Loc;
198    }
199  }
200
201  // FIXME: We are at an unreachable point, there is no reason to emit the block
202  // unless it has uses. However, we still need a place to put the debug
203  // region.end for now.
204
205  EmitBlock(ReturnBlock.getBlock());
206  return llvm::DebugLoc();
207}
208
209static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) {
210  if (!BB) return;
211  if (!BB->use_empty())
212    return CGF.CurFn->getBasicBlockList().push_back(BB);
213  delete BB;
214}
215
216void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
217  assert(BreakContinueStack.empty() &&
218         "mismatched push/pop in break/continue stack!");
219
220  bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0
221    && NumSimpleReturnExprs == NumReturnExprs
222    && ReturnBlock.getBlock()->use_empty();
223  // Usually the return expression is evaluated before the cleanup
224  // code.  If the function contains only a simple return statement,
225  // such as a constant, the location before the cleanup code becomes
226  // the last useful breakpoint in the function, because the simple
227  // return expression will be evaluated after the cleanup code. To be
228  // safe, set the debug location for cleanup code to the location of
229  // the return statement.  Otherwise the cleanup code should be at the
230  // end of the function's lexical scope.
231  //
232  // If there are multiple branches to the return block, the branch
233  // instructions will get the location of the return statements and
234  // all will be fine.
235  if (CGDebugInfo *DI = getDebugInfo()) {
236    if (OnlySimpleReturnStmts)
237      DI->EmitLocation(Builder, LastStopPoint);
238    else
239      DI->EmitLocation(Builder, EndLoc);
240  }
241
242  // Pop any cleanups that might have been associated with the
243  // parameters.  Do this in whatever block we're currently in; it's
244  // important to do this before we enter the return block or return
245  // edges will be *really* confused.
246  bool EmitRetDbgLoc = true;
247  if (EHStack.stable_begin() != PrologueCleanupDepth) {
248    // Make sure the line table doesn't jump back into the body for
249    // the ret after it's been at EndLoc.
250    EmitRetDbgLoc = false;
251
252    if (CGDebugInfo *DI = getDebugInfo())
253      if (OnlySimpleReturnStmts)
254        DI->EmitLocation(Builder, EndLoc);
255
256    PopCleanupBlocks(PrologueCleanupDepth);
257  }
258
259  // Emit function epilog (to return).
260  llvm::DebugLoc Loc = EmitReturnBlock();
261
262  if (ShouldInstrumentFunction())
263    EmitFunctionInstrumentation("__cyg_profile_func_exit");
264
265  // Emit debug descriptor for function end.
266  if (CGDebugInfo *DI = getDebugInfo())
267    DI->EmitFunctionEnd(Builder);
268
269  // Reset the debug location to that of the simple 'return' expression, if any
270  // rather than that of the end of the function's scope '}'.
271  ApplyDebugLocation AL(*this, Loc);
272  EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc, EndLoc);
273  EmitEndEHSpec(CurCodeDecl);
274
275  assert(EHStack.empty() &&
276         "did not remove all scopes from cleanup stack!");
277
278  // If someone did an indirect goto, emit the indirect goto block at the end of
279  // the function.
280  if (IndirectBranch) {
281    EmitBlock(IndirectBranch->getParent());
282    Builder.ClearInsertionPoint();
283  }
284
285  // If some of our locals escaped, insert a call to llvm.frameescape in the
286  // entry block.
287  if (!EscapedLocals.empty()) {
288    // Invert the map from local to index into a simple vector. There should be
289    // no holes.
290    SmallVector<llvm::Value *, 4> EscapeArgs;
291    EscapeArgs.resize(EscapedLocals.size());
292    for (auto &Pair : EscapedLocals)
293      EscapeArgs[Pair.second] = Pair.first;
294    llvm::Function *FrameEscapeFn = llvm::Intrinsic::getDeclaration(
295        &CGM.getModule(), llvm::Intrinsic::frameescape);
296    CGBuilderTy(AllocaInsertPt).CreateCall(FrameEscapeFn, EscapeArgs);
297  }
298
299  // Remove the AllocaInsertPt instruction, which is just a convenience for us.
300  llvm::Instruction *Ptr = AllocaInsertPt;
301  AllocaInsertPt = nullptr;
302  Ptr->eraseFromParent();
303
304  // If someone took the address of a label but never did an indirect goto, we
305  // made a zero entry PHI node, which is illegal, zap it now.
306  if (IndirectBranch) {
307    llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress());
308    if (PN->getNumIncomingValues() == 0) {
309      PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType()));
310      PN->eraseFromParent();
311    }
312  }
313
314  EmitIfUsed(*this, EHResumeBlock);
315  EmitIfUsed(*this, TerminateLandingPad);
316  EmitIfUsed(*this, TerminateHandler);
317  EmitIfUsed(*this, UnreachableBlock);
318
319  if (CGM.getCodeGenOpts().EmitDeclMetadata)
320    EmitDeclMetadata();
321
322  for (SmallVectorImpl<std::pair<llvm::Instruction *, llvm::Value *> >::iterator
323           I = DeferredReplacements.begin(),
324           E = DeferredReplacements.end();
325       I != E; ++I) {
326    I->first->replaceAllUsesWith(I->second);
327    I->first->eraseFromParent();
328  }
329}
330
331/// ShouldInstrumentFunction - Return true if the current function should be
332/// instrumented with __cyg_profile_func_* calls
333bool CodeGenFunction::ShouldInstrumentFunction() {
334  if (!CGM.getCodeGenOpts().InstrumentFunctions)
335    return false;
336  if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>())
337    return false;
338  return true;
339}
340
341/// EmitFunctionInstrumentation - Emit LLVM code to call the specified
342/// instrumentation function with the current function and the call site, if
343/// function instrumentation is enabled.
344void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) {
345  // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site);
346  llvm::PointerType *PointerTy = Int8PtrTy;
347  llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy };
348  llvm::FunctionType *FunctionTy =
349    llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false);
350
351  llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn);
352  llvm::CallInst *CallSite = Builder.CreateCall(
353    CGM.getIntrinsic(llvm::Intrinsic::returnaddress),
354    llvm::ConstantInt::get(Int32Ty, 0),
355    "callsite");
356
357  llvm::Value *args[] = {
358    llvm::ConstantExpr::getBitCast(CurFn, PointerTy),
359    CallSite
360  };
361
362  EmitNounwindRuntimeCall(F, args);
363}
364
365void CodeGenFunction::EmitMCountInstrumentation() {
366  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
367
368  llvm::Constant *MCountFn =
369    CGM.CreateRuntimeFunction(FTy, getTarget().getMCountName());
370  EmitNounwindRuntimeCall(MCountFn);
371}
372
373// OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument
374// information in the program executable. The argument information stored
375// includes the argument name, its type, the address and access qualifiers used.
376static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn,
377                                 CodeGenModule &CGM, llvm::LLVMContext &Context,
378                                 SmallVector<llvm::Metadata *, 5> &kernelMDArgs,
379                                 CGBuilderTy &Builder, ASTContext &ASTCtx) {
380  // Create MDNodes that represent the kernel arg metadata.
381  // Each MDNode is a list in the form of "key", N number of values which is
382  // the same number of values as their are kernel arguments.
383
384  const PrintingPolicy &Policy = ASTCtx.getPrintingPolicy();
385
386  // MDNode for the kernel argument address space qualifiers.
387  SmallVector<llvm::Metadata *, 8> addressQuals;
388  addressQuals.push_back(llvm::MDString::get(Context, "kernel_arg_addr_space"));
389
390  // MDNode for the kernel argument access qualifiers (images only).
391  SmallVector<llvm::Metadata *, 8> accessQuals;
392  accessQuals.push_back(llvm::MDString::get(Context, "kernel_arg_access_qual"));
393
394  // MDNode for the kernel argument type names.
395  SmallVector<llvm::Metadata *, 8> argTypeNames;
396  argTypeNames.push_back(llvm::MDString::get(Context, "kernel_arg_type"));
397
398  // MDNode for the kernel argument base type names.
399  SmallVector<llvm::Metadata *, 8> argBaseTypeNames;
400  argBaseTypeNames.push_back(
401      llvm::MDString::get(Context, "kernel_arg_base_type"));
402
403  // MDNode for the kernel argument type qualifiers.
404  SmallVector<llvm::Metadata *, 8> argTypeQuals;
405  argTypeQuals.push_back(llvm::MDString::get(Context, "kernel_arg_type_qual"));
406
407  // MDNode for the kernel argument names.
408  SmallVector<llvm::Metadata *, 8> argNames;
409  argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name"));
410
411  for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
412    const ParmVarDecl *parm = FD->getParamDecl(i);
413    QualType ty = parm->getType();
414    std::string typeQuals;
415
416    if (ty->isPointerType()) {
417      QualType pointeeTy = ty->getPointeeType();
418
419      // Get address qualifier.
420      addressQuals.push_back(llvm::ConstantAsMetadata::get(Builder.getInt32(
421          ASTCtx.getTargetAddressSpace(pointeeTy.getAddressSpace()))));
422
423      // Get argument type name.
424      std::string typeName =
425          pointeeTy.getUnqualifiedType().getAsString(Policy) + "*";
426
427      // Turn "unsigned type" to "utype"
428      std::string::size_type pos = typeName.find("unsigned");
429      if (pointeeTy.isCanonical() && pos != std::string::npos)
430        typeName.erase(pos+1, 8);
431
432      argTypeNames.push_back(llvm::MDString::get(Context, typeName));
433
434      std::string baseTypeName =
435          pointeeTy.getUnqualifiedType().getCanonicalType().getAsString(
436              Policy) +
437          "*";
438
439      // Turn "unsigned type" to "utype"
440      pos = baseTypeName.find("unsigned");
441      if (pos != std::string::npos)
442        baseTypeName.erase(pos+1, 8);
443
444      argBaseTypeNames.push_back(llvm::MDString::get(Context, baseTypeName));
445
446      // Get argument type qualifiers:
447      if (ty.isRestrictQualified())
448        typeQuals = "restrict";
449      if (pointeeTy.isConstQualified() ||
450          (pointeeTy.getAddressSpace() == LangAS::opencl_constant))
451        typeQuals += typeQuals.empty() ? "const" : " const";
452      if (pointeeTy.isVolatileQualified())
453        typeQuals += typeQuals.empty() ? "volatile" : " volatile";
454    } else {
455      uint32_t AddrSpc = 0;
456      if (ty->isImageType())
457        AddrSpc =
458          CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
459
460      addressQuals.push_back(
461          llvm::ConstantAsMetadata::get(Builder.getInt32(AddrSpc)));
462
463      // Get argument type name.
464      std::string typeName = ty.getUnqualifiedType().getAsString(Policy);
465
466      // Turn "unsigned type" to "utype"
467      std::string::size_type pos = typeName.find("unsigned");
468      if (ty.isCanonical() && pos != std::string::npos)
469        typeName.erase(pos+1, 8);
470
471      argTypeNames.push_back(llvm::MDString::get(Context, typeName));
472
473      std::string baseTypeName =
474          ty.getUnqualifiedType().getCanonicalType().getAsString(Policy);
475
476      // Turn "unsigned type" to "utype"
477      pos = baseTypeName.find("unsigned");
478      if (pos != std::string::npos)
479        baseTypeName.erase(pos+1, 8);
480
481      argBaseTypeNames.push_back(llvm::MDString::get(Context, baseTypeName));
482
483      // Get argument type qualifiers:
484      if (ty.isConstQualified())
485        typeQuals = "const";
486      if (ty.isVolatileQualified())
487        typeQuals += typeQuals.empty() ? "volatile" : " volatile";
488    }
489
490    argTypeQuals.push_back(llvm::MDString::get(Context, typeQuals));
491
492    // Get image access qualifier:
493    if (ty->isImageType()) {
494      const OpenCLImageAccessAttr *A = parm->getAttr<OpenCLImageAccessAttr>();
495      if (A && A->isWriteOnly())
496        accessQuals.push_back(llvm::MDString::get(Context, "write_only"));
497      else
498        accessQuals.push_back(llvm::MDString::get(Context, "read_only"));
499      // FIXME: what about read_write?
500    } else
501      accessQuals.push_back(llvm::MDString::get(Context, "none"));
502
503    // Get argument name.
504    argNames.push_back(llvm::MDString::get(Context, parm->getName()));
505  }
506
507  kernelMDArgs.push_back(llvm::MDNode::get(Context, addressQuals));
508  kernelMDArgs.push_back(llvm::MDNode::get(Context, accessQuals));
509  kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeNames));
510  kernelMDArgs.push_back(llvm::MDNode::get(Context, argBaseTypeNames));
511  kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeQuals));
512  if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata)
513    kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames));
514}
515
516void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD,
517                                               llvm::Function *Fn)
518{
519  if (!FD->hasAttr<OpenCLKernelAttr>())
520    return;
521
522  llvm::LLVMContext &Context = getLLVMContext();
523
524  SmallVector<llvm::Metadata *, 5> kernelMDArgs;
525  kernelMDArgs.push_back(llvm::ConstantAsMetadata::get(Fn));
526
527  GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs, Builder,
528                       getContext());
529
530  if (const VecTypeHintAttr *A = FD->getAttr<VecTypeHintAttr>()) {
531    QualType hintQTy = A->getTypeHint();
532    const ExtVectorType *hintEltQTy = hintQTy->getAs<ExtVectorType>();
533    bool isSignedInteger =
534        hintQTy->isSignedIntegerType() ||
535        (hintEltQTy && hintEltQTy->getElementType()->isSignedIntegerType());
536    llvm::Metadata *attrMDArgs[] = {
537        llvm::MDString::get(Context, "vec_type_hint"),
538        llvm::ConstantAsMetadata::get(llvm::UndefValue::get(
539            CGM.getTypes().ConvertType(A->getTypeHint()))),
540        llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
541            llvm::IntegerType::get(Context, 32),
542            llvm::APInt(32, (uint64_t)(isSignedInteger ? 1 : 0))))};
543    kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
544  }
545
546  if (const WorkGroupSizeHintAttr *A = FD->getAttr<WorkGroupSizeHintAttr>()) {
547    llvm::Metadata *attrMDArgs[] = {
548        llvm::MDString::get(Context, "work_group_size_hint"),
549        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())),
550        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())),
551        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))};
552    kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
553  }
554
555  if (const ReqdWorkGroupSizeAttr *A = FD->getAttr<ReqdWorkGroupSizeAttr>()) {
556    llvm::Metadata *attrMDArgs[] = {
557        llvm::MDString::get(Context, "reqd_work_group_size"),
558        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getXDim())),
559        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getYDim())),
560        llvm::ConstantAsMetadata::get(Builder.getInt32(A->getZDim()))};
561    kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
562  }
563
564  llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs);
565  llvm::NamedMDNode *OpenCLKernelMetadata =
566    CGM.getModule().getOrInsertNamedMetadata("opencl.kernels");
567  OpenCLKernelMetadata->addOperand(kernelMDNode);
568}
569
570/// Determine whether the function F ends with a return stmt.
571static bool endsWithReturn(const Decl* F) {
572  const Stmt *Body = nullptr;
573  if (auto *FD = dyn_cast_or_null<FunctionDecl>(F))
574    Body = FD->getBody();
575  else if (auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(F))
576    Body = OMD->getBody();
577
578  if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
579    auto LastStmt = CS->body_rbegin();
580    if (LastStmt != CS->body_rend())
581      return isa<ReturnStmt>(*LastStmt);
582  }
583  return false;
584}
585
586void CodeGenFunction::StartFunction(GlobalDecl GD,
587                                    QualType RetTy,
588                                    llvm::Function *Fn,
589                                    const CGFunctionInfo &FnInfo,
590                                    const FunctionArgList &Args,
591                                    SourceLocation Loc,
592                                    SourceLocation StartLoc) {
593  assert(!CurFn &&
594         "Do not use a CodeGenFunction object for more than one function");
595
596  const Decl *D = GD.getDecl();
597
598  DidCallStackSave = false;
599  CurCodeDecl = D;
600  CurFuncDecl = (D ? D->getNonClosureContext() : nullptr);
601  FnRetTy = RetTy;
602  CurFn = Fn;
603  CurFnInfo = &FnInfo;
604  assert(CurFn->isDeclaration() && "Function already has body?");
605
606  if (CGM.isInSanitizerBlacklist(Fn, Loc))
607    SanOpts.clear();
608
609  // Pass inline keyword to optimizer if it appears explicitly on any
610  // declaration. Also, in the case of -fno-inline attach NoInline
611  // attribute to all function that are not marked AlwaysInline.
612  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
613    if (!CGM.getCodeGenOpts().NoInline) {
614      for (auto RI : FD->redecls())
615        if (RI->isInlineSpecified()) {
616          Fn->addFnAttr(llvm::Attribute::InlineHint);
617          break;
618        }
619    } else if (!FD->hasAttr<AlwaysInlineAttr>())
620      Fn->addFnAttr(llvm::Attribute::NoInline);
621  }
622
623  if (getLangOpts().OpenCL) {
624    // Add metadata for a kernel function.
625    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
626      EmitOpenCLKernelMetadata(FD, Fn);
627  }
628
629  // If we are checking function types, emit a function type signature as
630  // prologue data.
631  if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function)) {
632    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
633      if (llvm::Constant *PrologueSig =
634              CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) {
635        llvm::Constant *FTRTTIConst =
636            CGM.GetAddrOfRTTIDescriptor(FD->getType(), /*ForEH=*/true);
637        llvm::Constant *PrologueStructElems[] = { PrologueSig, FTRTTIConst };
638        llvm::Constant *PrologueStructConst =
639            llvm::ConstantStruct::getAnon(PrologueStructElems, /*Packed=*/true);
640        Fn->setPrologueData(PrologueStructConst);
641      }
642    }
643  }
644
645  llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn);
646
647  // Create a marker to make it easy to insert allocas into the entryblock
648  // later.  Don't create this with the builder, because we don't want it
649  // folded.
650  llvm::Value *Undef = llvm::UndefValue::get(Int32Ty);
651  AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB);
652  if (Builder.isNamePreserving())
653    AllocaInsertPt->setName("allocapt");
654
655  ReturnBlock = getJumpDestInCurrentScope("return");
656
657  Builder.SetInsertPoint(EntryBB);
658
659  // Emit subprogram debug descriptor.
660  if (CGDebugInfo *DI = getDebugInfo()) {
661    SmallVector<QualType, 16> ArgTypes;
662    for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
663	 i != e; ++i) {
664      ArgTypes.push_back((*i)->getType());
665    }
666
667    QualType FnType =
668      getContext().getFunctionType(RetTy, ArgTypes,
669                                   FunctionProtoType::ExtProtoInfo());
670    DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder);
671  }
672
673  if (ShouldInstrumentFunction())
674    EmitFunctionInstrumentation("__cyg_profile_func_enter");
675
676  if (CGM.getCodeGenOpts().InstrumentForProfiling)
677    EmitMCountInstrumentation();
678
679  if (RetTy->isVoidType()) {
680    // Void type; nothing to return.
681    ReturnValue = nullptr;
682
683    // Count the implicit return.
684    if (!endsWithReturn(D))
685      ++NumReturnExprs;
686  } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect &&
687             !hasScalarEvaluationKind(CurFnInfo->getReturnType())) {
688    // Indirect aggregate return; emit returned value directly into sret slot.
689    // This reduces code size, and affects correctness in C++.
690    auto AI = CurFn->arg_begin();
691    if (CurFnInfo->getReturnInfo().isSRetAfterThis())
692      ++AI;
693    ReturnValue = AI;
694  } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca &&
695             !hasScalarEvaluationKind(CurFnInfo->getReturnType())) {
696    // Load the sret pointer from the argument struct and return into that.
697    unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex();
698    llvm::Function::arg_iterator EI = CurFn->arg_end();
699    --EI;
700    llvm::Value *Addr = Builder.CreateStructGEP(nullptr, EI, Idx);
701    ReturnValue = Builder.CreateLoad(Addr, "agg.result");
702  } else {
703    ReturnValue = CreateIRTemp(RetTy, "retval");
704
705    // Tell the epilog emitter to autorelease the result.  We do this
706    // now so that various specialized functions can suppress it
707    // during their IR-generation.
708    if (getLangOpts().ObjCAutoRefCount &&
709        !CurFnInfo->isReturnsRetained() &&
710        RetTy->isObjCRetainableType())
711      AutoreleaseResult = true;
712  }
713
714  EmitStartEHSpec(CurCodeDecl);
715
716  PrologueCleanupDepth = EHStack.stable_begin();
717  EmitFunctionProlog(*CurFnInfo, CurFn, Args);
718
719  if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) {
720    CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
721    const CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
722    if (MD->getParent()->isLambda() &&
723        MD->getOverloadedOperator() == OO_Call) {
724      // We're in a lambda; figure out the captures.
725      MD->getParent()->getCaptureFields(LambdaCaptureFields,
726                                        LambdaThisCaptureField);
727      if (LambdaThisCaptureField) {
728        // If this lambda captures this, load it.
729        LValue ThisLValue = EmitLValueForLambdaField(LambdaThisCaptureField);
730        CXXThisValue = EmitLoadOfLValue(ThisLValue,
731                                        SourceLocation()).getScalarVal();
732      }
733      for (auto *FD : MD->getParent()->fields()) {
734        if (FD->hasCapturedVLAType()) {
735          auto *ExprArg = EmitLoadOfLValue(EmitLValueForLambdaField(FD),
736                                           SourceLocation()).getScalarVal();
737          auto VAT = FD->getCapturedVLAType();
738          VLASizeMap[VAT->getSizeExpr()] = ExprArg;
739        }
740      }
741    } else {
742      // Not in a lambda; just use 'this' from the method.
743      // FIXME: Should we generate a new load for each use of 'this'?  The
744      // fast register allocator would be happier...
745      CXXThisValue = CXXABIThisValue;
746    }
747  }
748
749  // If any of the arguments have a variably modified type, make sure to
750  // emit the type size.
751  for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
752       i != e; ++i) {
753    const VarDecl *VD = *i;
754
755    // Dig out the type as written from ParmVarDecls; it's unclear whether
756    // the standard (C99 6.9.1p10) requires this, but we're following the
757    // precedent set by gcc.
758    QualType Ty;
759    if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD))
760      Ty = PVD->getOriginalType();
761    else
762      Ty = VD->getType();
763
764    if (Ty->isVariablyModifiedType())
765      EmitVariablyModifiedType(Ty);
766  }
767  // Emit a location at the end of the prologue.
768  if (CGDebugInfo *DI = getDebugInfo())
769    DI->EmitLocation(Builder, StartLoc);
770}
771
772void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args,
773                                       const Stmt *Body) {
774  RegionCounter Cnt = getPGORegionCounter(Body);
775  Cnt.beginRegion(Builder);
776  if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body))
777    EmitCompoundStmtWithoutScope(*S);
778  else
779    EmitStmt(Body);
780}
781
782/// When instrumenting to collect profile data, the counts for some blocks
783/// such as switch cases need to not include the fall-through counts, so
784/// emit a branch around the instrumentation code. When not instrumenting,
785/// this just calls EmitBlock().
786void CodeGenFunction::EmitBlockWithFallThrough(llvm::BasicBlock *BB,
787                                               RegionCounter &Cnt) {
788  llvm::BasicBlock *SkipCountBB = nullptr;
789  if (HaveInsertPoint() && CGM.getCodeGenOpts().ProfileInstrGenerate) {
790    // When instrumenting for profiling, the fallthrough to certain
791    // statements needs to skip over the instrumentation code so that we
792    // get an accurate count.
793    SkipCountBB = createBasicBlock("skipcount");
794    EmitBranch(SkipCountBB);
795  }
796  EmitBlock(BB);
797  Cnt.beginRegion(Builder, /*AddIncomingFallThrough=*/true);
798  if (SkipCountBB)
799    EmitBlock(SkipCountBB);
800}
801
802/// Tries to mark the given function nounwind based on the
803/// non-existence of any throwing calls within it.  We believe this is
804/// lightweight enough to do at -O0.
805static void TryMarkNoThrow(llvm::Function *F) {
806  // LLVM treats 'nounwind' on a function as part of the type, so we
807  // can't do this on functions that can be overwritten.
808  if (F->mayBeOverridden()) return;
809
810  for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
811    for (llvm::BasicBlock::iterator
812           BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
813      if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) {
814        if (!Call->doesNotThrow())
815          return;
816      } else if (isa<llvm::ResumeInst>(&*BI)) {
817        return;
818      }
819  F->setDoesNotThrow();
820}
821
822void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
823                                   const CGFunctionInfo &FnInfo) {
824  const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
825
826  // Check if we should generate debug info for this function.
827  if (FD->hasAttr<NoDebugAttr>())
828    DebugInfo = nullptr; // disable debug info indefinitely for this function
829
830  FunctionArgList Args;
831  QualType ResTy = FD->getReturnType();
832
833  CurGD = GD;
834  const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
835  if (MD && MD->isInstance()) {
836    if (CGM.getCXXABI().HasThisReturn(GD))
837      ResTy = MD->getThisType(getContext());
838    else if (CGM.getCXXABI().hasMostDerivedReturn(GD))
839      ResTy = CGM.getContext().VoidPtrTy;
840    CGM.getCXXABI().buildThisParam(*this, Args);
841  }
842
843  Args.append(FD->param_begin(), FD->param_end());
844
845  if (MD && (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)))
846    CGM.getCXXABI().addImplicitStructorParams(*this, ResTy, Args);
847
848  SourceRange BodyRange;
849  if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange();
850  CurEHLocation = BodyRange.getEnd();
851
852  // Use the location of the start of the function to determine where
853  // the function definition is located. By default use the location
854  // of the declaration as the location for the subprogram. A function
855  // may lack a declaration in the source code if it is created by code
856  // gen. (examples: _GLOBAL__I_a, __cxx_global_array_dtor, thunk).
857  SourceLocation Loc = FD->getLocation();
858
859  // If this is a function specialization then use the pattern body
860  // as the location for the function.
861  if (const FunctionDecl *SpecDecl = FD->getTemplateInstantiationPattern())
862    if (SpecDecl->hasBody(SpecDecl))
863      Loc = SpecDecl->getLocation();
864
865  // Emit the standard function prologue.
866  StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin());
867
868  // Generate the body of the function.
869  PGO.checkGlobalDecl(GD);
870  PGO.assignRegionCounters(GD.getDecl(), CurFn);
871  if (isa<CXXDestructorDecl>(FD))
872    EmitDestructorBody(Args);
873  else if (isa<CXXConstructorDecl>(FD))
874    EmitConstructorBody(Args);
875  else if (getLangOpts().CUDA &&
876           !getLangOpts().CUDAIsDevice &&
877           FD->hasAttr<CUDAGlobalAttr>())
878    CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args);
879  else if (isa<CXXConversionDecl>(FD) &&
880           cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) {
881    // The lambda conversion to block pointer is special; the semantics can't be
882    // expressed in the AST, so IRGen needs to special-case it.
883    EmitLambdaToBlockPointerBody(Args);
884  } else if (isa<CXXMethodDecl>(FD) &&
885             cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) {
886    // The lambda static invoker function is special, because it forwards or
887    // clones the body of the function call operator (but is actually static).
888    EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD));
889  } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) &&
890             (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() ||
891              cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) {
892    // Implicit copy-assignment gets the same special treatment as implicit
893    // copy-constructors.
894    emitImplicitAssignmentOperatorBody(Args);
895  } else if (Stmt *Body = FD->getBody()) {
896    EmitFunctionBody(Args, Body);
897  } else
898    llvm_unreachable("no definition for emitted function");
899
900  // C++11 [stmt.return]p2:
901  //   Flowing off the end of a function [...] results in undefined behavior in
902  //   a value-returning function.
903  // C11 6.9.1p12:
904  //   If the '}' that terminates a function is reached, and the value of the
905  //   function call is used by the caller, the behavior is undefined.
906  if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && !SawAsmBlock &&
907      !FD->getReturnType()->isVoidType() && Builder.GetInsertBlock()) {
908    if (SanOpts.has(SanitizerKind::Return)) {
909      SanitizerScope SanScope(this);
910      llvm::Value *IsFalse = Builder.getFalse();
911      EmitCheck(std::make_pair(IsFalse, SanitizerKind::Return),
912                "missing_return", EmitCheckSourceLocation(FD->getLocation()),
913                None);
914    } else if (CGM.getCodeGenOpts().OptimizationLevel == 0)
915      Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap));
916    Builder.CreateUnreachable();
917    Builder.ClearInsertionPoint();
918  }
919
920  // Emit the standard function epilogue.
921  FinishFunction(BodyRange.getEnd());
922
923  // If we haven't marked the function nothrow through other means, do
924  // a quick pass now to see if we can.
925  if (!CurFn->doesNotThrow())
926    TryMarkNoThrow(CurFn);
927}
928
929/// ContainsLabel - Return true if the statement contains a label in it.  If
930/// this statement is not executed normally, it not containing a label means
931/// that we can just remove the code.
932bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) {
933  // Null statement, not a label!
934  if (!S) return false;
935
936  // If this is a label, we have to emit the code, consider something like:
937  // if (0) {  ...  foo:  bar(); }  goto foo;
938  //
939  // TODO: If anyone cared, we could track __label__'s, since we know that you
940  // can't jump to one from outside their declared region.
941  if (isa<LabelStmt>(S))
942    return true;
943
944  // If this is a case/default statement, and we haven't seen a switch, we have
945  // to emit the code.
946  if (isa<SwitchCase>(S) && !IgnoreCaseStmts)
947    return true;
948
949  // If this is a switch statement, we want to ignore cases below it.
950  if (isa<SwitchStmt>(S))
951    IgnoreCaseStmts = true;
952
953  // Scan subexpressions for verboten labels.
954  for (Stmt::const_child_range I = S->children(); I; ++I)
955    if (ContainsLabel(*I, IgnoreCaseStmts))
956      return true;
957
958  return false;
959}
960
961/// containsBreak - Return true if the statement contains a break out of it.
962/// If the statement (recursively) contains a switch or loop with a break
963/// inside of it, this is fine.
964bool CodeGenFunction::containsBreak(const Stmt *S) {
965  // Null statement, not a label!
966  if (!S) return false;
967
968  // If this is a switch or loop that defines its own break scope, then we can
969  // include it and anything inside of it.
970  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) ||
971      isa<ForStmt>(S))
972    return false;
973
974  if (isa<BreakStmt>(S))
975    return true;
976
977  // Scan subexpressions for verboten breaks.
978  for (Stmt::const_child_range I = S->children(); I; ++I)
979    if (containsBreak(*I))
980      return true;
981
982  return false;
983}
984
985
986/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
987/// to a constant, or if it does but contains a label, return false.  If it
988/// constant folds return true and set the boolean result in Result.
989bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
990                                                   bool &ResultBool) {
991  llvm::APSInt ResultInt;
992  if (!ConstantFoldsToSimpleInteger(Cond, ResultInt))
993    return false;
994
995  ResultBool = ResultInt.getBoolValue();
996  return true;
997}
998
999/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
1000/// to a constant, or if it does but contains a label, return false.  If it
1001/// constant folds return true and set the folded value.
1002bool CodeGenFunction::
1003ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt) {
1004  // FIXME: Rename and handle conversion of other evaluatable things
1005  // to bool.
1006  llvm::APSInt Int;
1007  if (!Cond->EvaluateAsInt(Int, getContext()))
1008    return false;  // Not foldable, not integer or not fully evaluatable.
1009
1010  if (CodeGenFunction::ContainsLabel(Cond))
1011    return false;  // Contains a label.
1012
1013  ResultInt = Int;
1014  return true;
1015}
1016
1017
1018
1019/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if
1020/// statement) to the specified blocks.  Based on the condition, this might try
1021/// to simplify the codegen of the conditional based on the branch.
1022///
1023void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
1024                                           llvm::BasicBlock *TrueBlock,
1025                                           llvm::BasicBlock *FalseBlock,
1026                                           uint64_t TrueCount) {
1027  Cond = Cond->IgnoreParens();
1028
1029  if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
1030
1031    // Handle X && Y in a condition.
1032    if (CondBOp->getOpcode() == BO_LAnd) {
1033      RegionCounter Cnt = getPGORegionCounter(CondBOp);
1034
1035      // If we have "1 && X", simplify the code.  "0 && X" would have constant
1036      // folded if the case was simple enough.
1037      bool ConstantBool = false;
1038      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
1039          ConstantBool) {
1040        // br(1 && X) -> br(X).
1041        Cnt.beginRegion(Builder);
1042        return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock,
1043                                    TrueCount);
1044      }
1045
1046      // If we have "X && 1", simplify the code to use an uncond branch.
1047      // "X && 0" would have been constant folded to 0.
1048      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
1049          ConstantBool) {
1050        // br(X && 1) -> br(X).
1051        return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock,
1052                                    TrueCount);
1053      }
1054
1055      // Emit the LHS as a conditional.  If the LHS conditional is false, we
1056      // want to jump to the FalseBlock.
1057      llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true");
1058      // The counter tells us how often we evaluate RHS, and all of TrueCount
1059      // can be propagated to that branch.
1060      uint64_t RHSCount = Cnt.getCount();
1061
1062      ConditionalEvaluation eval(*this);
1063      {
1064        ApplyDebugLocation DL(*this, Cond);
1065        EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount);
1066        EmitBlock(LHSTrue);
1067      }
1068
1069      // Any temporaries created here are conditional.
1070      Cnt.beginRegion(Builder);
1071      eval.begin(*this);
1072      EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, TrueCount);
1073      eval.end(*this);
1074
1075      return;
1076    }
1077
1078    if (CondBOp->getOpcode() == BO_LOr) {
1079      RegionCounter Cnt = getPGORegionCounter(CondBOp);
1080
1081      // If we have "0 || X", simplify the code.  "1 || X" would have constant
1082      // folded if the case was simple enough.
1083      bool ConstantBool = false;
1084      if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
1085          !ConstantBool) {
1086        // br(0 || X) -> br(X).
1087        Cnt.beginRegion(Builder);
1088        return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock,
1089                                    TrueCount);
1090      }
1091
1092      // If we have "X || 0", simplify the code to use an uncond branch.
1093      // "X || 1" would have been constant folded to 1.
1094      if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
1095          !ConstantBool) {
1096        // br(X || 0) -> br(X).
1097        return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock,
1098                                    TrueCount);
1099      }
1100
1101      // Emit the LHS as a conditional.  If the LHS conditional is true, we
1102      // want to jump to the TrueBlock.
1103      llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false");
1104      // We have the count for entry to the RHS and for the whole expression
1105      // being true, so we can divy up True count between the short circuit and
1106      // the RHS.
1107      uint64_t LHSCount = Cnt.getParentCount() - Cnt.getCount();
1108      uint64_t RHSCount = TrueCount - LHSCount;
1109
1110      ConditionalEvaluation eval(*this);
1111      {
1112        ApplyDebugLocation DL(*this, Cond);
1113        EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount);
1114        EmitBlock(LHSFalse);
1115      }
1116
1117      // Any temporaries created here are conditional.
1118      Cnt.beginRegion(Builder);
1119      eval.begin(*this);
1120      EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, RHSCount);
1121
1122      eval.end(*this);
1123
1124      return;
1125    }
1126  }
1127
1128  if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) {
1129    // br(!x, t, f) -> br(x, f, t)
1130    if (CondUOp->getOpcode() == UO_LNot) {
1131      // Negate the count.
1132      uint64_t FalseCount = PGO.getCurrentRegionCount() - TrueCount;
1133      // Negate the condition and swap the destination blocks.
1134      return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock,
1135                                  FalseCount);
1136    }
1137  }
1138
1139  if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) {
1140    // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f))
1141    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1142    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1143
1144    RegionCounter Cnt = getPGORegionCounter(CondOp);
1145    ConditionalEvaluation cond(*this);
1146    EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock, Cnt.getCount());
1147
1148    // When computing PGO branch weights, we only know the overall count for
1149    // the true block. This code is essentially doing tail duplication of the
1150    // naive code-gen, introducing new edges for which counts are not
1151    // available. Divide the counts proportionally between the LHS and RHS of
1152    // the conditional operator.
1153    uint64_t LHSScaledTrueCount = 0;
1154    if (TrueCount) {
1155      double LHSRatio = Cnt.getCount() / (double) Cnt.getParentCount();
1156      LHSScaledTrueCount = TrueCount * LHSRatio;
1157    }
1158
1159    cond.begin(*this);
1160    EmitBlock(LHSBlock);
1161    Cnt.beginRegion(Builder);
1162    {
1163      ApplyDebugLocation DL(*this, Cond);
1164      EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock,
1165                           LHSScaledTrueCount);
1166    }
1167    cond.end(*this);
1168
1169    cond.begin(*this);
1170    EmitBlock(RHSBlock);
1171    EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock,
1172                         TrueCount - LHSScaledTrueCount);
1173    cond.end(*this);
1174
1175    return;
1176  }
1177
1178  if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) {
1179    // Conditional operator handling can give us a throw expression as a
1180    // condition for a case like:
1181    //   br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f)
1182    // Fold this to:
1183    //   br(c, throw x, br(y, t, f))
1184    EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false);
1185    return;
1186  }
1187
1188  // Create branch weights based on the number of times we get here and the
1189  // number of times the condition should be true.
1190  uint64_t CurrentCount = std::max(PGO.getCurrentRegionCount(), TrueCount);
1191  llvm::MDNode *Weights = PGO.createBranchWeights(TrueCount,
1192                                                  CurrentCount - TrueCount);
1193
1194  // Emit the code with the fully general case.
1195  llvm::Value *CondV;
1196  {
1197    ApplyDebugLocation DL(*this, Cond);
1198    CondV = EvaluateExprAsBool(Cond);
1199  }
1200  Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights);
1201}
1202
1203/// ErrorUnsupported - Print out an error that codegen doesn't support the
1204/// specified stmt yet.
1205void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) {
1206  CGM.ErrorUnsupported(S, Type);
1207}
1208
1209/// emitNonZeroVLAInit - Emit the "zero" initialization of a
1210/// variable-length array whose elements have a non-zero bit-pattern.
1211///
1212/// \param baseType the inner-most element type of the array
1213/// \param src - a char* pointing to the bit-pattern for a single
1214/// base element of the array
1215/// \param sizeInChars - the total size of the VLA, in chars
1216static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType,
1217                               llvm::Value *dest, llvm::Value *src,
1218                               llvm::Value *sizeInChars) {
1219  std::pair<CharUnits,CharUnits> baseSizeAndAlign
1220    = CGF.getContext().getTypeInfoInChars(baseType);
1221
1222  CGBuilderTy &Builder = CGF.Builder;
1223
1224  llvm::Value *baseSizeInChars
1225    = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity());
1226
1227  llvm::Type *i8p = Builder.getInt8PtrTy();
1228
1229  llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin");
1230  llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end");
1231
1232  llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock();
1233  llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop");
1234  llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont");
1235
1236  // Make a loop over the VLA.  C99 guarantees that the VLA element
1237  // count must be nonzero.
1238  CGF.EmitBlock(loopBB);
1239
1240  llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur");
1241  cur->addIncoming(begin, originBB);
1242
1243  // memcpy the individual element bit-pattern.
1244  Builder.CreateMemCpy(cur, src, baseSizeInChars,
1245                       baseSizeAndAlign.second.getQuantity(),
1246                       /*volatile*/ false);
1247
1248  // Go to the next element.
1249  llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(Builder.getInt8Ty(),
1250                                                         cur, 1, "vla.next");
1251
1252  // Leave if that's the end of the VLA.
1253  llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone");
1254  Builder.CreateCondBr(done, contBB, loopBB);
1255  cur->addIncoming(next, loopBB);
1256
1257  CGF.EmitBlock(contBB);
1258}
1259
1260void
1261CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
1262  // Ignore empty classes in C++.
1263  if (getLangOpts().CPlusPlus) {
1264    if (const RecordType *RT = Ty->getAs<RecordType>()) {
1265      if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty())
1266        return;
1267    }
1268  }
1269
1270  // Cast the dest ptr to the appropriate i8 pointer type.
1271  unsigned DestAS =
1272    cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace();
1273  llvm::Type *BP = Builder.getInt8PtrTy(DestAS);
1274  if (DestPtr->getType() != BP)
1275    DestPtr = Builder.CreateBitCast(DestPtr, BP);
1276
1277  // Get size and alignment info for this aggregate.
1278  std::pair<CharUnits, CharUnits> TypeInfo =
1279    getContext().getTypeInfoInChars(Ty);
1280  CharUnits Size = TypeInfo.first;
1281  CharUnits Align = TypeInfo.second;
1282
1283  llvm::Value *SizeVal;
1284  const VariableArrayType *vla;
1285
1286  // Don't bother emitting a zero-byte memset.
1287  if (Size.isZero()) {
1288    // But note that getTypeInfo returns 0 for a VLA.
1289    if (const VariableArrayType *vlaType =
1290          dyn_cast_or_null<VariableArrayType>(
1291                                          getContext().getAsArrayType(Ty))) {
1292      QualType eltType;
1293      llvm::Value *numElts;
1294      std::tie(numElts, eltType) = getVLASize(vlaType);
1295
1296      SizeVal = numElts;
1297      CharUnits eltSize = getContext().getTypeSizeInChars(eltType);
1298      if (!eltSize.isOne())
1299        SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize));
1300      vla = vlaType;
1301    } else {
1302      return;
1303    }
1304  } else {
1305    SizeVal = CGM.getSize(Size);
1306    vla = nullptr;
1307  }
1308
1309  // If the type contains a pointer to data member we can't memset it to zero.
1310  // Instead, create a null constant and copy it to the destination.
1311  // TODO: there are other patterns besides zero that we can usefully memset,
1312  // like -1, which happens to be the pattern used by member-pointers.
1313  if (!CGM.getTypes().isZeroInitializable(Ty)) {
1314    // For a VLA, emit a single element, then splat that over the VLA.
1315    if (vla) Ty = getContext().getBaseElementType(vla);
1316
1317    llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty);
1318
1319    llvm::GlobalVariable *NullVariable =
1320      new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(),
1321                               /*isConstant=*/true,
1322                               llvm::GlobalVariable::PrivateLinkage,
1323                               NullConstant, Twine());
1324    llvm::Value *SrcPtr =
1325      Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy());
1326
1327    if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal);
1328
1329    // Get and call the appropriate llvm.memcpy overload.
1330    Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false);
1331    return;
1332  }
1333
1334  // Otherwise, just memset the whole thing to zero.  This is legal
1335  // because in LLVM, all default initializers (other than the ones we just
1336  // handled above) are guaranteed to have a bit pattern of all zeros.
1337  Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal,
1338                       Align.getQuantity(), false);
1339}
1340
1341llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) {
1342  // Make sure that there is a block for the indirect goto.
1343  if (!IndirectBranch)
1344    GetIndirectGotoBlock();
1345
1346  llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock();
1347
1348  // Make sure the indirect branch includes all of the address-taken blocks.
1349  IndirectBranch->addDestination(BB);
1350  return llvm::BlockAddress::get(CurFn, BB);
1351}
1352
1353llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
1354  // If we already made the indirect branch for indirect goto, return its block.
1355  if (IndirectBranch) return IndirectBranch->getParent();
1356
1357  CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto"));
1358
1359  // Create the PHI node that indirect gotos will add entries to.
1360  llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0,
1361                                              "indirect.goto.dest");
1362
1363  // Create the indirect branch instruction.
1364  IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal);
1365  return IndirectBranch->getParent();
1366}
1367
1368/// Computes the length of an array in elements, as well as the base
1369/// element type and a properly-typed first element pointer.
1370llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType,
1371                                              QualType &baseType,
1372                                              llvm::Value *&addr) {
1373  const ArrayType *arrayType = origArrayType;
1374
1375  // If it's a VLA, we have to load the stored size.  Note that
1376  // this is the size of the VLA in bytes, not its size in elements.
1377  llvm::Value *numVLAElements = nullptr;
1378  if (isa<VariableArrayType>(arrayType)) {
1379    numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first;
1380
1381    // Walk into all VLAs.  This doesn't require changes to addr,
1382    // which has type T* where T is the first non-VLA element type.
1383    do {
1384      QualType elementType = arrayType->getElementType();
1385      arrayType = getContext().getAsArrayType(elementType);
1386
1387      // If we only have VLA components, 'addr' requires no adjustment.
1388      if (!arrayType) {
1389        baseType = elementType;
1390        return numVLAElements;
1391      }
1392    } while (isa<VariableArrayType>(arrayType));
1393
1394    // We get out here only if we find a constant array type
1395    // inside the VLA.
1396  }
1397
1398  // We have some number of constant-length arrays, so addr should
1399  // have LLVM type [M x [N x [...]]]*.  Build a GEP that walks
1400  // down to the first element of addr.
1401  SmallVector<llvm::Value*, 8> gepIndices;
1402
1403  // GEP down to the array type.
1404  llvm::ConstantInt *zero = Builder.getInt32(0);
1405  gepIndices.push_back(zero);
1406
1407  uint64_t countFromCLAs = 1;
1408  QualType eltType;
1409
1410  llvm::ArrayType *llvmArrayType =
1411    dyn_cast<llvm::ArrayType>(
1412      cast<llvm::PointerType>(addr->getType())->getElementType());
1413  while (llvmArrayType) {
1414    assert(isa<ConstantArrayType>(arrayType));
1415    assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue()
1416             == llvmArrayType->getNumElements());
1417
1418    gepIndices.push_back(zero);
1419    countFromCLAs *= llvmArrayType->getNumElements();
1420    eltType = arrayType->getElementType();
1421
1422    llvmArrayType =
1423      dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType());
1424    arrayType = getContext().getAsArrayType(arrayType->getElementType());
1425    assert((!llvmArrayType || arrayType) &&
1426           "LLVM and Clang types are out-of-synch");
1427  }
1428
1429  if (arrayType) {
1430    // From this point onwards, the Clang array type has been emitted
1431    // as some other type (probably a packed struct). Compute the array
1432    // size, and just emit the 'begin' expression as a bitcast.
1433    while (arrayType) {
1434      countFromCLAs *=
1435          cast<ConstantArrayType>(arrayType)->getSize().getZExtValue();
1436      eltType = arrayType->getElementType();
1437      arrayType = getContext().getAsArrayType(eltType);
1438    }
1439
1440    unsigned AddressSpace = addr->getType()->getPointerAddressSpace();
1441    llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace);
1442    addr = Builder.CreateBitCast(addr, BaseType, "array.begin");
1443  } else {
1444    // Create the actual GEP.
1445    addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin");
1446  }
1447
1448  baseType = eltType;
1449
1450  llvm::Value *numElements
1451    = llvm::ConstantInt::get(SizeTy, countFromCLAs);
1452
1453  // If we had any VLA dimensions, factor them in.
1454  if (numVLAElements)
1455    numElements = Builder.CreateNUWMul(numVLAElements, numElements);
1456
1457  return numElements;
1458}
1459
1460std::pair<llvm::Value*, QualType>
1461CodeGenFunction::getVLASize(QualType type) {
1462  const VariableArrayType *vla = getContext().getAsVariableArrayType(type);
1463  assert(vla && "type was not a variable array type!");
1464  return getVLASize(vla);
1465}
1466
1467std::pair<llvm::Value*, QualType>
1468CodeGenFunction::getVLASize(const VariableArrayType *type) {
1469  // The number of elements so far; always size_t.
1470  llvm::Value *numElements = nullptr;
1471
1472  QualType elementType;
1473  do {
1474    elementType = type->getElementType();
1475    llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()];
1476    assert(vlaSize && "no size for VLA!");
1477    assert(vlaSize->getType() == SizeTy);
1478
1479    if (!numElements) {
1480      numElements = vlaSize;
1481    } else {
1482      // It's undefined behavior if this wraps around, so mark it that way.
1483      // FIXME: Teach -fsanitize=undefined to trap this.
1484      numElements = Builder.CreateNUWMul(numElements, vlaSize);
1485    }
1486  } while ((type = getContext().getAsVariableArrayType(elementType)));
1487
1488  return std::pair<llvm::Value*,QualType>(numElements, elementType);
1489}
1490
1491void CodeGenFunction::EmitVariablyModifiedType(QualType type) {
1492  assert(type->isVariablyModifiedType() &&
1493         "Must pass variably modified type to EmitVLASizes!");
1494
1495  EnsureInsertPoint();
1496
1497  // We're going to walk down into the type and look for VLA
1498  // expressions.
1499  do {
1500    assert(type->isVariablyModifiedType());
1501
1502    const Type *ty = type.getTypePtr();
1503    switch (ty->getTypeClass()) {
1504
1505#define TYPE(Class, Base)
1506#define ABSTRACT_TYPE(Class, Base)
1507#define NON_CANONICAL_TYPE(Class, Base)
1508#define DEPENDENT_TYPE(Class, Base) case Type::Class:
1509#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base)
1510#include "clang/AST/TypeNodes.def"
1511      llvm_unreachable("unexpected dependent type!");
1512
1513    // These types are never variably-modified.
1514    case Type::Builtin:
1515    case Type::Complex:
1516    case Type::Vector:
1517    case Type::ExtVector:
1518    case Type::Record:
1519    case Type::Enum:
1520    case Type::Elaborated:
1521    case Type::TemplateSpecialization:
1522    case Type::ObjCObject:
1523    case Type::ObjCInterface:
1524    case Type::ObjCObjectPointer:
1525      llvm_unreachable("type class is never variably-modified!");
1526
1527    case Type::Adjusted:
1528      type = cast<AdjustedType>(ty)->getAdjustedType();
1529      break;
1530
1531    case Type::Decayed:
1532      type = cast<DecayedType>(ty)->getPointeeType();
1533      break;
1534
1535    case Type::Pointer:
1536      type = cast<PointerType>(ty)->getPointeeType();
1537      break;
1538
1539    case Type::BlockPointer:
1540      type = cast<BlockPointerType>(ty)->getPointeeType();
1541      break;
1542
1543    case Type::LValueReference:
1544    case Type::RValueReference:
1545      type = cast<ReferenceType>(ty)->getPointeeType();
1546      break;
1547
1548    case Type::MemberPointer:
1549      type = cast<MemberPointerType>(ty)->getPointeeType();
1550      break;
1551
1552    case Type::ConstantArray:
1553    case Type::IncompleteArray:
1554      // Losing element qualification here is fine.
1555      type = cast<ArrayType>(ty)->getElementType();
1556      break;
1557
1558    case Type::VariableArray: {
1559      // Losing element qualification here is fine.
1560      const VariableArrayType *vat = cast<VariableArrayType>(ty);
1561
1562      // Unknown size indication requires no size computation.
1563      // Otherwise, evaluate and record it.
1564      if (const Expr *size = vat->getSizeExpr()) {
1565        // It's possible that we might have emitted this already,
1566        // e.g. with a typedef and a pointer to it.
1567        llvm::Value *&entry = VLASizeMap[size];
1568        if (!entry) {
1569          llvm::Value *Size = EmitScalarExpr(size);
1570
1571          // C11 6.7.6.2p5:
1572          //   If the size is an expression that is not an integer constant
1573          //   expression [...] each time it is evaluated it shall have a value
1574          //   greater than zero.
1575          if (SanOpts.has(SanitizerKind::VLABound) &&
1576              size->getType()->isSignedIntegerType()) {
1577            SanitizerScope SanScope(this);
1578            llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType());
1579            llvm::Constant *StaticArgs[] = {
1580              EmitCheckSourceLocation(size->getLocStart()),
1581              EmitCheckTypeDescriptor(size->getType())
1582            };
1583            EmitCheck(std::make_pair(Builder.CreateICmpSGT(Size, Zero),
1584                                     SanitizerKind::VLABound),
1585                      "vla_bound_not_positive", StaticArgs, Size);
1586          }
1587
1588          // Always zexting here would be wrong if it weren't
1589          // undefined behavior to have a negative bound.
1590          entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false);
1591        }
1592      }
1593      type = vat->getElementType();
1594      break;
1595    }
1596
1597    case Type::FunctionProto:
1598    case Type::FunctionNoProto:
1599      type = cast<FunctionType>(ty)->getReturnType();
1600      break;
1601
1602    case Type::Paren:
1603    case Type::TypeOf:
1604    case Type::UnaryTransform:
1605    case Type::Attributed:
1606    case Type::SubstTemplateTypeParm:
1607    case Type::PackExpansion:
1608      // Keep walking after single level desugaring.
1609      type = type.getSingleStepDesugaredType(getContext());
1610      break;
1611
1612    case Type::Typedef:
1613    case Type::Decltype:
1614    case Type::Auto:
1615      // Stop walking: nothing to do.
1616      return;
1617
1618    case Type::TypeOfExpr:
1619      // Stop walking: emit typeof expression.
1620      EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr());
1621      return;
1622
1623    case Type::Atomic:
1624      type = cast<AtomicType>(ty)->getValueType();
1625      break;
1626    }
1627  } while (type->isVariablyModifiedType());
1628}
1629
1630llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) {
1631  if (getContext().getBuiltinVaListType()->isArrayType())
1632    return EmitScalarExpr(E);
1633  return EmitLValue(E).getAddress();
1634}
1635
1636void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E,
1637                                              llvm::Constant *Init) {
1638  assert (Init && "Invalid DeclRefExpr initializer!");
1639  if (CGDebugInfo *Dbg = getDebugInfo())
1640    if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo)
1641      Dbg->EmitGlobalVariable(E->getDecl(), Init);
1642}
1643
1644CodeGenFunction::PeepholeProtection
1645CodeGenFunction::protectFromPeepholes(RValue rvalue) {
1646  // At the moment, the only aggressive peephole we do in IR gen
1647  // is trunc(zext) folding, but if we add more, we can easily
1648  // extend this protection.
1649
1650  if (!rvalue.isScalar()) return PeepholeProtection();
1651  llvm::Value *value = rvalue.getScalarVal();
1652  if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection();
1653
1654  // Just make an extra bitcast.
1655  assert(HaveInsertPoint());
1656  llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "",
1657                                                  Builder.GetInsertBlock());
1658
1659  PeepholeProtection protection;
1660  protection.Inst = inst;
1661  return protection;
1662}
1663
1664void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) {
1665  if (!protection.Inst) return;
1666
1667  // In theory, we could try to duplicate the peepholes now, but whatever.
1668  protection.Inst->eraseFromParent();
1669}
1670
1671llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn,
1672                                                 llvm::Value *AnnotatedVal,
1673                                                 StringRef AnnotationStr,
1674                                                 SourceLocation Location) {
1675  llvm::Value *Args[4] = {
1676    AnnotatedVal,
1677    Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy),
1678    Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy),
1679    CGM.EmitAnnotationLineNo(Location)
1680  };
1681  return Builder.CreateCall(AnnotationFn, Args);
1682}
1683
1684void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) {
1685  assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
1686  // FIXME We create a new bitcast for every annotation because that's what
1687  // llvm-gcc was doing.
1688  for (const auto *I : D->specific_attrs<AnnotateAttr>())
1689    EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation),
1690                       Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()),
1691                       I->getAnnotation(), D->getLocation());
1692}
1693
1694llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
1695                                                   llvm::Value *V) {
1696  assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
1697  llvm::Type *VTy = V->getType();
1698  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation,
1699                                    CGM.Int8PtrTy);
1700
1701  for (const auto *I : D->specific_attrs<AnnotateAttr>()) {
1702    // FIXME Always emit the cast inst so we can differentiate between
1703    // annotation on the first field of a struct and annotation on the struct
1704    // itself.
1705    if (VTy != CGM.Int8PtrTy)
1706      V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy));
1707    V = EmitAnnotationCall(F, V, I->getAnnotation(), D->getLocation());
1708    V = Builder.CreateBitCast(V, VTy);
1709  }
1710
1711  return V;
1712}
1713
1714CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { }
1715
1716CodeGenFunction::SanitizerScope::SanitizerScope(CodeGenFunction *CGF)
1717    : CGF(CGF) {
1718  assert(!CGF->IsSanitizerScope);
1719  CGF->IsSanitizerScope = true;
1720}
1721
1722CodeGenFunction::SanitizerScope::~SanitizerScope() {
1723  CGF->IsSanitizerScope = false;
1724}
1725
1726void CodeGenFunction::InsertHelper(llvm::Instruction *I,
1727                                   const llvm::Twine &Name,
1728                                   llvm::BasicBlock *BB,
1729                                   llvm::BasicBlock::iterator InsertPt) const {
1730  LoopStack.InsertHelper(I);
1731  if (IsSanitizerScope)
1732    CGM.getSanitizerMetadata()->disableSanitizerForInstruction(I);
1733}
1734
1735template <bool PreserveNames>
1736void CGBuilderInserter<PreserveNames>::InsertHelper(
1737    llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB,
1738    llvm::BasicBlock::iterator InsertPt) const {
1739  llvm::IRBuilderDefaultInserter<PreserveNames>::InsertHelper(I, Name, BB,
1740                                                              InsertPt);
1741  if (CGF)
1742    CGF->InsertHelper(I, Name, BB, InsertPt);
1743}
1744
1745#ifdef NDEBUG
1746#define PreserveNames false
1747#else
1748#define PreserveNames true
1749#endif
1750template void CGBuilderInserter<PreserveNames>::InsertHelper(
1751    llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB,
1752    llvm::BasicBlock::iterator InsertPt) const;
1753#undef PreserveNames
1754