diff options
Diffstat (limited to 'lib/CodeGen/CGExprConstant.cpp')
| -rw-r--r-- | lib/CodeGen/CGExprConstant.cpp | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp index b90b3ab61d8e..acfb9b6dbb25 100644 --- a/lib/CodeGen/CGExprConstant.cpp +++ b/lib/CodeGen/CGExprConstant.cpp @@ -33,6 +33,7 @@ using namespace CodeGen; //===----------------------------------------------------------------------===// namespace { +class ConstExprEmitter; class ConstStructBuilder { CodeGenModule &CGM; CodeGenFunction *CGF; @@ -42,6 +43,10 @@ class ConstStructBuilder { CharUnits LLVMStructAlignment; SmallVector<llvm::Constant *, 32> Elements; public: + static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CFG, + ConstExprEmitter *Emitter, + llvm::ConstantStruct *Base, + InitListExpr *Updater); static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, InitListExpr *ILE); static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, @@ -68,6 +73,8 @@ private: void ConvertStructToPacked(); bool Build(InitListExpr *ILE); + bool Build(ConstExprEmitter *Emitter, llvm::ConstantStruct *Base, + InitListExpr *Updater); void Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase, const CXXRecordDecl *VTableClass, CharUnits BaseOffset); llvm::Constant *Finalize(QualType Ty); @@ -547,6 +554,17 @@ llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) { llvm::Constant *ConstStructBuilder::BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, + ConstExprEmitter *Emitter, + llvm::ConstantStruct *Base, + InitListExpr *Updater) { + ConstStructBuilder Builder(CGM, CGF); + if (!Builder.Build(Emitter, Base, Updater)) + return nullptr; + return Builder.Finalize(Updater->getType()); +} + +llvm::Constant *ConstStructBuilder::BuildStruct(CodeGenModule &CGM, + CodeGenFunction *CGF, InitListExpr *ILE) { ConstStructBuilder Builder(CGM, CGF); @@ -818,6 +836,82 @@ public: return nullptr; } + llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base, + InitListExpr *Updater) { + QualType ExprType = Updater->getType(); + + if (ExprType->isArrayType()) { + llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(ExprType)); + llvm::Type *ElemType = AType->getElementType(); + + unsigned NumInitElements = Updater->getNumInits(); + unsigned NumElements = AType->getNumElements(); + + std::vector<llvm::Constant *> Elts; + Elts.reserve(NumElements); + + if (llvm::ConstantDataArray *DataArray = + dyn_cast<llvm::ConstantDataArray>(Base)) + for (unsigned i = 0; i != NumElements; ++i) + Elts.push_back(DataArray->getElementAsConstant(i)); + else if (llvm::ConstantArray *Array = + dyn_cast<llvm::ConstantArray>(Base)) + for (unsigned i = 0; i != NumElements; ++i) + Elts.push_back(Array->getOperand(i)); + else + return nullptr; // FIXME: other array types not implemented + + llvm::Constant *fillC = nullptr; + if (Expr *filler = Updater->getArrayFiller()) + if (!isa<NoInitExpr>(filler)) + fillC = CGM.EmitConstantExpr(filler, filler->getType(), CGF); + bool RewriteType = (fillC && fillC->getType() != ElemType); + + for (unsigned i = 0; i != NumElements; ++i) { + Expr *Init = nullptr; + if (i < NumInitElements) + Init = Updater->getInit(i); + + if (!Init && fillC) + Elts[i] = fillC; + else if (!Init || isa<NoInitExpr>(Init)) + ; // Do nothing. + else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) + Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE); + else + Elts[i] = CGM.EmitConstantExpr(Init, Init->getType(), CGF); + + if (!Elts[i]) + return nullptr; + RewriteType |= (Elts[i]->getType() != ElemType); + } + + if (RewriteType) { + std::vector<llvm::Type *> Types; + Types.reserve(NumElements); + for (unsigned i = 0; i != NumElements; ++i) + Types.push_back(Elts[i]->getType()); + llvm::StructType *SType = llvm::StructType::get(AType->getContext(), + Types, true); + return llvm::ConstantStruct::get(SType, Elts); + } + + return llvm::ConstantArray::get(AType, Elts); + } + + if (ExprType->isRecordType()) + return ConstStructBuilder::BuildStruct(CGM, CGF, this, + dyn_cast<llvm::ConstantStruct>(Base), Updater); + + return nullptr; + } + + llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) { + return EmitDesignatedInitUpdater( + CGM.EmitConstantExpr(E->getBase(), E->getType(), CGF), + E->getUpdater()); + } + llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E) { if (!E->getConstructor()->isTrivial()) return nullptr; @@ -1003,6 +1097,68 @@ public: } // end anonymous namespace. +bool ConstStructBuilder::Build(ConstExprEmitter *Emitter, + llvm::ConstantStruct *Base, + InitListExpr *Updater) { + assert(Base && "base expression should not be empty"); + + QualType ExprType = Updater->getType(); + RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl(); + const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); + const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout( + Base->getType()); + unsigned FieldNo = -1; + unsigned ElementNo = 0; + + for (FieldDecl *Field : RD->fields()) { + ++FieldNo; + + if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field) + continue; + + // Skip anonymous bitfields. + if (Field->isUnnamedBitfield()) + continue; + + llvm::Constant *EltInit = Base->getOperand(ElementNo); + + // Bail out if the type of the ConstantStruct does not have the same layout + // as the type of the InitListExpr. + if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() || + Layout.getFieldOffset(ElementNo) != + BaseLayout->getElementOffsetInBits(ElementNo)) + return false; + + // Get the initializer. If we encounter an empty field or a NoInitExpr, + // we use values from the base expression. + Expr *Init = nullptr; + if (ElementNo < Updater->getNumInits()) + Init = Updater->getInit(ElementNo); + + if (!Init || isa<NoInitExpr>(Init)) + ; // Do nothing. + else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) + EltInit = Emitter->EmitDesignatedInitUpdater(EltInit, ChildILE); + else + EltInit = CGM.EmitConstantExpr(Init, Field->getType(), CGF); + + ++ElementNo; + + if (!EltInit) + return false; + + if (!Field->isBitField()) + AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit); + else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit)) + AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI); + else + // Initializing a bitfield with a non-trivial constant? + return false; + } + + return true; +} + llvm::Constant *CodeGenModule::EmitConstantInit(const VarDecl &D, CodeGenFunction *CGF) { // Make a quick check if variable can be default NULL initialized |