diff options
| -rw-r--r-- | clang/lib/CodeGen/CGDecl.cpp | 103 |
1 files changed, 56 insertions, 47 deletions
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp index 57b2fbadbee..3a5bc0e4694 100644 --- a/clang/lib/CodeGen/CGDecl.cpp +++ b/clang/lib/CodeGen/CGDecl.cpp @@ -1055,6 +1055,61 @@ static BytePattern shouldUseMemSetToInitialize(llvm::Constant *Init, return constantIsRepeatedBytePattern(Init); } +static void emitStoresForConstant(CodeGenModule &CGM, const VarDecl &D, + Address Loc, bool isVolatile, + CGBuilderTy &Builder, + llvm::Constant *constant) { + auto *Int8Ty = llvm::IntegerType::getInt8Ty(CGM.getLLVMContext()); + auto *IntPtrTy = CGM.getDataLayout().getIntPtrType(CGM.getLLVMContext()); + + // If the initializer is all or mostly the same, codegen with bzero / memset + // then do a few stores afterward. + uint64_t ConstantSize = + CGM.getDataLayout().getTypeAllocSize(constant->getType()); + auto *SizeVal = llvm::ConstantInt::get(IntPtrTy, ConstantSize); + if (shouldUseBZeroPlusStoresToInitialize(constant, ConstantSize)) { + Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal, + isVolatile); + + bool valueAlreadyCorrect = + constant->isNullValue() || isa<llvm::UndefValue>(constant); + if (!valueAlreadyCorrect) { + Loc = Builder.CreateBitCast( + Loc, constant->getType()->getPointerTo(Loc.getAddressSpace())); + emitStoresForInitAfterBZero(CGM, constant, Loc, isVolatile, Builder); + } + return; + } + + BytePattern Pattern = shouldUseMemSetToInitialize(constant, ConstantSize); + if (!Pattern.isNone()) { + uint8_t Value = Pattern.isAny() ? 0x00 : Pattern.getValue(); + Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, Value), SizeVal, + isVolatile); + return; + } + + // Otherwise, create a temporary global with the initializer then memcpy from + // the global to the alloca. + std::string Name = getStaticDeclName(CGM, D); + unsigned AS = CGM.getContext().getTargetAddressSpace( + CGM.getStringLiteralAddressSpace()); + llvm::Type *BP = llvm::PointerType::getInt8PtrTy(CGM.getLLVMContext(), AS); + + llvm::GlobalVariable *GV = new llvm::GlobalVariable( + CGM.getModule(), constant->getType(), true, + llvm::GlobalValue::PrivateLinkage, constant, Name, nullptr, + llvm::GlobalValue::NotThreadLocal, AS); + GV->setAlignment(Loc.getAlignment().getQuantity()); + GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); + + Address SrcPtr = Address(GV, Loc.getAlignment()); + if (SrcPtr.getType() != BP) + SrcPtr = Builder.CreateBitCast(SrcPtr, BP); + + Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, isVolatile); +} + /// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a /// variable declaration with auto, register, or no storage class specifier. /// These turn into simple stack objects, or GlobalValues depending on target. @@ -1500,57 +1555,11 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) { // in various ways. bool isVolatile = type.isVolatileQualified(); - llvm::Value *SizeVal = - llvm::ConstantInt::get(IntPtrTy, - getContext().getTypeSizeInChars(type).getQuantity()); - llvm::Type *BP = CGM.Int8Ty->getPointerTo(Loc.getAddressSpace()); if (Loc.getType() != BP) Loc = Builder.CreateBitCast(Loc, BP); - // If the initializer is all or mostly the same, codegen with bzero / memset - // then do a few stores afterward. - uint64_t ConstantSize = - CGM.getDataLayout().getTypeAllocSize(constant->getType()); - if (shouldUseBZeroPlusStoresToInitialize(constant, ConstantSize)) { - Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal, - isVolatile); - // Zero and undef don't require a stores. - if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) { - Loc = Builder.CreateBitCast(Loc, - constant->getType()->getPointerTo(Loc.getAddressSpace())); - emitStoresForInitAfterBZero(CGM, constant, Loc, isVolatile, Builder); - } - return; - } - - BytePattern Pattern = shouldUseMemSetToInitialize(constant, ConstantSize); - if (!Pattern.isNone()) { - uint8_t Value = Pattern.isAny() ? 0x00 : Pattern.getValue(); - Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, Value), SizeVal, - isVolatile); - return; - } - - // Otherwise, create a temporary global with the initializer then - // memcpy from the global to the alloca. - std::string Name = getStaticDeclName(CGM, D); - unsigned AS = CGM.getContext().getTargetAddressSpace( - CGM.getStringLiteralAddressSpace()); - BP = llvm::PointerType::getInt8PtrTy(getLLVMContext(), AS); - - llvm::GlobalVariable *GV = new llvm::GlobalVariable( - CGM.getModule(), constant->getType(), true, - llvm::GlobalValue::PrivateLinkage, constant, Name, nullptr, - llvm::GlobalValue::NotThreadLocal, AS); - GV->setAlignment(Loc.getAlignment().getQuantity()); - GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); - - Address SrcPtr = Address(GV, Loc.getAlignment()); - if (SrcPtr.getType() != BP) - SrcPtr = Builder.CreateBitCast(SrcPtr, BP); - - Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, isVolatile); + emitStoresForConstant(CGM, D, Loc, isVolatile, Builder, constant); } /// Emit an expression as an initializer for an object (variable, field, etc.) |
