Check in LLVM r95781.
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
new file mode 100644
index 0000000..5800ce7
--- /dev/null
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -0,0 +1,1056 @@
+//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Constant Expr nodes as LLVM code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "CGObjCRuntime.h"
+#include "clang/AST/APValue.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Basic/Builtins.h"
+#include "llvm/Constants.h"
+#include "llvm/Function.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/Target/TargetData.h"
+using namespace clang;
+using namespace CodeGen;
+
+namespace {
+class ConstStructBuilder {
+ CodeGenModule &CGM;
+ CodeGenFunction *CGF;
+
+ bool Packed;
+
+ unsigned NextFieldOffsetInBytes;
+
+ unsigned LLVMStructAlignment;
+
+ std::vector<llvm::Constant *> Elements;
+
+ ConstStructBuilder(CodeGenModule &CGM, CodeGenFunction *CGF)
+ : CGM(CGM), CGF(CGF), Packed(false), NextFieldOffsetInBytes(0),
+ LLVMStructAlignment(1) { }
+
+ bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
+ const Expr *InitExpr) {
+ uint64_t FieldOffsetInBytes = FieldOffset / 8;
+
+ assert(NextFieldOffsetInBytes <= FieldOffsetInBytes
+ && "Field offset mismatch!");
+
+ // Emit the field.
+ llvm::Constant *C = CGM.EmitConstantExpr(InitExpr, Field->getType(), CGF);
+ if (!C)
+ return false;
+
+ unsigned FieldAlignment = getAlignment(C);
+
+ // Round up the field offset to the alignment of the field type.
+ uint64_t AlignedNextFieldOffsetInBytes =
+ llvm::RoundUpToAlignment(NextFieldOffsetInBytes, FieldAlignment);
+
+ if (AlignedNextFieldOffsetInBytes > FieldOffsetInBytes) {
+ assert(!Packed && "Alignment is wrong even with a packed struct!");
+
+ // Convert the struct to a packed struct.
+ ConvertStructToPacked();
+
+ AlignedNextFieldOffsetInBytes = NextFieldOffsetInBytes;
+ }
+
+ if (AlignedNextFieldOffsetInBytes < FieldOffsetInBytes) {
+ // We need to append padding.
+ AppendPadding(FieldOffsetInBytes - NextFieldOffsetInBytes);
+
+ assert(NextFieldOffsetInBytes == FieldOffsetInBytes &&
+ "Did not add enough padding!");
+
+ AlignedNextFieldOffsetInBytes = NextFieldOffsetInBytes;
+ }
+
+ // Add the field.
+ Elements.push_back(C);
+ NextFieldOffsetInBytes = AlignedNextFieldOffsetInBytes + getSizeInBytes(C);
+
+ if (Packed)
+ assert(LLVMStructAlignment == 1 && "Packed struct not byte-aligned!");
+ else
+ LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
+
+ return true;
+ }
+
+ bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
+ const Expr *InitExpr) {
+ llvm::ConstantInt *CI =
+ cast_or_null<llvm::ConstantInt>(CGM.EmitConstantExpr(InitExpr,
+ Field->getType(),
+ CGF));
+ // FIXME: Can this ever happen?
+ if (!CI)
+ return false;
+
+ if (FieldOffset > NextFieldOffsetInBytes * 8) {
+ // We need to add padding.
+ uint64_t NumBytes =
+ llvm::RoundUpToAlignment(FieldOffset -
+ NextFieldOffsetInBytes * 8, 8) / 8;
+
+ AppendPadding(NumBytes);
+ }
+
+ uint64_t FieldSize =
+ Field->getBitWidth()->EvaluateAsInt(CGM.getContext()).getZExtValue();
+
+ llvm::APInt FieldValue = CI->getValue();
+
+ // Promote the size of FieldValue if necessary
+ // FIXME: This should never occur, but currently it can because initializer
+ // constants are cast to bool, and because clang is not enforcing bitfield
+ // width limits.
+ if (FieldSize > FieldValue.getBitWidth())
+ FieldValue.zext(FieldSize);
+
+ // Truncate the size of FieldValue to the bit field size.
+ if (FieldSize < FieldValue.getBitWidth())
+ FieldValue.trunc(FieldSize);
+
+ if (FieldOffset < NextFieldOffsetInBytes * 8) {
+ // Either part of the field or the entire field can go into the previous
+ // byte.
+ assert(!Elements.empty() && "Elements can't be empty!");
+
+ unsigned BitsInPreviousByte =
+ NextFieldOffsetInBytes * 8 - FieldOffset;
+
+ bool FitsCompletelyInPreviousByte =
+ BitsInPreviousByte >= FieldValue.getBitWidth();
+
+ llvm::APInt Tmp = FieldValue;
+
+ if (!FitsCompletelyInPreviousByte) {
+ unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
+
+ if (CGM.getTargetData().isBigEndian()) {
+ Tmp = Tmp.lshr(NewFieldWidth);
+ Tmp.trunc(BitsInPreviousByte);
+
+ // We want the remaining high bits.
+ FieldValue.trunc(NewFieldWidth);
+ } else {
+ Tmp.trunc(BitsInPreviousByte);
+
+ // We want the remaining low bits.
+ FieldValue = FieldValue.lshr(BitsInPreviousByte);
+ FieldValue.trunc(NewFieldWidth);
+ }
+ }
+
+ Tmp.zext(8);
+ if (CGM.getTargetData().isBigEndian()) {
+ if (FitsCompletelyInPreviousByte)
+ Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
+ } else {
+ Tmp = Tmp.shl(8 - BitsInPreviousByte);
+ }
+
+ // Or in the bits that go into the previous byte.
+ if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(Elements.back()))
+ Tmp |= Val->getValue();
+ else
+ assert(isa<llvm::UndefValue>(Elements.back()));
+
+ Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
+
+ if (FitsCompletelyInPreviousByte)
+ return true;
+ }
+
+ while (FieldValue.getBitWidth() > 8) {
+ llvm::APInt Tmp;
+
+ if (CGM.getTargetData().isBigEndian()) {
+ // We want the high bits.
+ Tmp = FieldValue;
+ Tmp = Tmp.lshr(Tmp.getBitWidth() - 8);
+ Tmp.trunc(8);
+ } else {
+ // We want the low bits.
+ Tmp = FieldValue;
+ Tmp.trunc(8);
+
+ FieldValue = FieldValue.lshr(8);
+ }
+
+ Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
+ NextFieldOffsetInBytes++;
+
+ FieldValue.trunc(FieldValue.getBitWidth() - 8);
+ }
+
+ assert(FieldValue.getBitWidth() > 0 &&
+ "Should have at least one bit left!");
+ assert(FieldValue.getBitWidth() <= 8 &&
+ "Should not have more than a byte left!");
+
+ if (FieldValue.getBitWidth() < 8) {
+ if (CGM.getTargetData().isBigEndian()) {
+ unsigned BitWidth = FieldValue.getBitWidth();
+
+ FieldValue.zext(8);
+ FieldValue = FieldValue << (8 - BitWidth);
+ } else
+ FieldValue.zext(8);
+ }
+
+ // Append the last element.
+ Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
+ FieldValue));
+ NextFieldOffsetInBytes++;
+ return true;
+ }
+
+ void AppendPadding(uint64_t NumBytes) {
+ if (!NumBytes)
+ return;
+
+ const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext());
+ if (NumBytes > 1)
+ Ty = llvm::ArrayType::get(Ty, NumBytes);
+
+ llvm::Constant *C = llvm::UndefValue::get(Ty);
+ Elements.push_back(C);
+ assert(getAlignment(C) == 1 && "Padding must have 1 byte alignment!");
+
+ NextFieldOffsetInBytes += getSizeInBytes(C);
+ }
+
+ void AppendTailPadding(uint64_t RecordSize) {
+ assert(RecordSize % 8 == 0 && "Invalid record size!");
+
+ uint64_t RecordSizeInBytes = RecordSize / 8;
+ assert(NextFieldOffsetInBytes <= RecordSizeInBytes && "Size mismatch!");
+
+ unsigned NumPadBytes = RecordSizeInBytes - NextFieldOffsetInBytes;
+ AppendPadding(NumPadBytes);
+ }
+
+ void ConvertStructToPacked() {
+ std::vector<llvm::Constant *> PackedElements;
+ uint64_t ElementOffsetInBytes = 0;
+
+ for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
+ llvm::Constant *C = Elements[i];
+
+ unsigned ElementAlign =
+ CGM.getTargetData().getABITypeAlignment(C->getType());
+ uint64_t AlignedElementOffsetInBytes =
+ llvm::RoundUpToAlignment(ElementOffsetInBytes, ElementAlign);
+
+ if (AlignedElementOffsetInBytes > ElementOffsetInBytes) {
+ // We need some padding.
+ uint64_t NumBytes =
+ AlignedElementOffsetInBytes - ElementOffsetInBytes;
+
+ const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext());
+ if (NumBytes > 1)
+ Ty = llvm::ArrayType::get(Ty, NumBytes);
+
+ llvm::Constant *Padding = llvm::UndefValue::get(Ty);
+ PackedElements.push_back(Padding);
+ ElementOffsetInBytes += getSizeInBytes(Padding);
+ }
+
+ PackedElements.push_back(C);
+ ElementOffsetInBytes += getSizeInBytes(C);
+ }
+
+ assert(ElementOffsetInBytes == NextFieldOffsetInBytes &&
+ "Packing the struct changed its size!");
+
+ Elements = PackedElements;
+ LLVMStructAlignment = 1;
+ Packed = true;
+ }
+
+ bool Build(InitListExpr *ILE) {
+ RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
+ const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
+
+ unsigned FieldNo = 0;
+ unsigned ElementNo = 0;
+ for (RecordDecl::field_iterator Field = RD->field_begin(),
+ FieldEnd = RD->field_end();
+ ElementNo < ILE->getNumInits() && Field != FieldEnd;
+ ++Field, ++FieldNo) {
+ if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
+ continue;
+
+ if (Field->isBitField()) {
+ if (!Field->getIdentifier())
+ continue;
+
+ if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo),
+ ILE->getInit(ElementNo)))
+ return false;
+ } else {
+ if (!AppendField(*Field, Layout.getFieldOffset(FieldNo),
+ ILE->getInit(ElementNo)))
+ return false;
+ }
+
+ ElementNo++;
+ }
+
+ uint64_t LayoutSizeInBytes = Layout.getSize() / 8;
+
+ if (NextFieldOffsetInBytes > LayoutSizeInBytes) {
+ // If the struct is bigger than the size of the record type,
+ // we must have a flexible array member at the end.
+ assert(RD->hasFlexibleArrayMember() &&
+ "Must have flexible array member if struct is bigger than type!");
+
+ // No tail padding is necessary.
+ return true;
+ }
+
+ uint64_t LLVMSizeInBytes = llvm::RoundUpToAlignment(NextFieldOffsetInBytes,
+ LLVMStructAlignment);
+
+ // Check if we need to convert the struct to a packed struct.
+ if (NextFieldOffsetInBytes <= LayoutSizeInBytes &&
+ LLVMSizeInBytes > LayoutSizeInBytes) {
+ assert(!Packed && "Size mismatch!");
+
+ ConvertStructToPacked();
+ assert(NextFieldOffsetInBytes == LayoutSizeInBytes &&
+ "Converting to packed did not help!");
+ }
+
+ // Append tail padding if necessary.
+ AppendTailPadding(Layout.getSize());
+
+ assert(Layout.getSize() / 8 == NextFieldOffsetInBytes &&
+ "Tail padding mismatch!");
+
+ return true;
+ }
+
+ unsigned getAlignment(const llvm::Constant *C) const {
+ if (Packed)
+ return 1;
+
+ return CGM.getTargetData().getABITypeAlignment(C->getType());
+ }
+
+ uint64_t getSizeInBytes(const llvm::Constant *C) const {
+ return CGM.getTargetData().getTypeAllocSize(C->getType());
+ }
+
+public:
+ static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF,
+ InitListExpr *ILE) {
+ ConstStructBuilder Builder(CGM, CGF);
+
+ if (!Builder.Build(ILE))
+ return 0;
+
+ llvm::Constant *Result =
+ llvm::ConstantStruct::get(CGM.getLLVMContext(),
+ Builder.Elements, Builder.Packed);
+
+ assert(llvm::RoundUpToAlignment(Builder.NextFieldOffsetInBytes,
+ Builder.getAlignment(Result)) ==
+ Builder.getSizeInBytes(Result) && "Size mismatch!");
+
+ return Result;
+ }
+};
+
+class ConstExprEmitter :
+ public StmtVisitor<ConstExprEmitter, llvm::Constant*> {
+ CodeGenModule &CGM;
+ CodeGenFunction *CGF;
+ llvm::LLVMContext &VMContext;
+public:
+ ConstExprEmitter(CodeGenModule &cgm, CodeGenFunction *cgf)
+ : CGM(cgm), CGF(cgf), VMContext(cgm.getLLVMContext()) {
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Visitor Methods
+ //===--------------------------------------------------------------------===//
+
+ llvm::Constant *VisitStmt(Stmt *S) {
+ return 0;
+ }
+
+ llvm::Constant *VisitParenExpr(ParenExpr *PE) {
+ return Visit(PE->getSubExpr());
+ }
+
+ llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
+ return Visit(E->getInitializer());
+ }
+
+ llvm::Constant *EmitMemberFunctionPointer(CXXMethodDecl *MD) {
+ assert(MD->isInstance() && "Member function must not be static!");
+
+ MD = MD->getCanonicalDecl();
+
+ const llvm::Type *PtrDiffTy =
+ CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
+
+ llvm::Constant *Values[2];
+
+ // Get the function pointer (or index if this is a virtual function).
+ if (MD->isVirtual()) {
+ uint64_t Index = CGM.getVtableInfo().getMethodVtableIndex(MD);
+
+ // Itanium C++ ABI 2.3:
+ // For a non-virtual function, this field is a simple function pointer.
+ // For a virtual function, it is 1 plus the virtual table offset
+ // (in bytes) of the function, represented as a ptrdiff_t.
+ Values[0] = llvm::ConstantInt::get(PtrDiffTy, (Index * 8) + 1);
+ } else {
+ const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
+ const llvm::Type *Ty =
+ CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
+ FPT->isVariadic());
+
+ llvm::Constant *FuncPtr = CGM.GetAddrOfFunction(MD, Ty);
+ Values[0] = llvm::ConstantExpr::getPtrToInt(FuncPtr, PtrDiffTy);
+ }
+
+ // The adjustment will always be 0.
+ Values[1] = llvm::ConstantInt::get(PtrDiffTy, 0);
+
+ return llvm::ConstantStruct::get(CGM.getLLVMContext(),
+ Values, 2, /*Packed=*/false);
+ }
+
+ llvm::Constant *VisitUnaryAddrOf(UnaryOperator *E) {
+ if (const MemberPointerType *MPT =
+ E->getType()->getAs<MemberPointerType>()) {
+ QualType T = MPT->getPointeeType();
+ DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr());
+
+ NamedDecl *ND = DRE->getDecl();
+ if (T->isFunctionProtoType())
+ return EmitMemberFunctionPointer(cast<CXXMethodDecl>(ND));
+
+ // We have a pointer to data member.
+ return CGM.EmitPointerToDataMember(cast<FieldDecl>(ND));
+ }
+
+ return 0;
+ }
+
+ llvm::Constant *VisitBinSub(BinaryOperator *E) {
+ // This must be a pointer/pointer subtraction. This only happens for
+ // address of label.
+ if (!isa<AddrLabelExpr>(E->getLHS()->IgnoreParenNoopCasts(CGM.getContext())) ||
+ !isa<AddrLabelExpr>(E->getRHS()->IgnoreParenNoopCasts(CGM.getContext())))
+ return 0;
+
+ llvm::Constant *LHS = CGM.EmitConstantExpr(E->getLHS(),
+ E->getLHS()->getType(), CGF);
+ llvm::Constant *RHS = CGM.EmitConstantExpr(E->getRHS(),
+ E->getRHS()->getType(), CGF);
+
+ const llvm::Type *ResultType = ConvertType(E->getType());
+ LHS = llvm::ConstantExpr::getPtrToInt(LHS, ResultType);
+ RHS = llvm::ConstantExpr::getPtrToInt(RHS, ResultType);
+
+ // No need to divide by element size, since addr of label is always void*,
+ // which has size 1 in GNUish.
+ return llvm::ConstantExpr::getSub(LHS, RHS);
+ }
+
+ llvm::Constant *VisitCastExpr(CastExpr* E) {
+ switch (E->getCastKind()) {
+ case CastExpr::CK_ToUnion: {
+ // GCC cast to union extension
+ assert(E->getType()->isUnionType() &&
+ "Destination type is not union type!");
+ const llvm::Type *Ty = ConvertType(E->getType());
+ Expr *SubExpr = E->getSubExpr();
+
+ llvm::Constant *C =
+ CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF);
+ if (!C)
+ return 0;
+
+ // Build a struct with the union sub-element as the first member,
+ // and padded to the appropriate size
+ std::vector<llvm::Constant*> Elts;
+ std::vector<const llvm::Type*> Types;
+ Elts.push_back(C);
+ Types.push_back(C->getType());
+ unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType());
+ unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(Ty);
+
+ assert(CurSize <= TotalSize && "Union size mismatch!");
+ if (unsigned NumPadBytes = TotalSize - CurSize) {
+ const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext);
+ if (NumPadBytes > 1)
+ Ty = llvm::ArrayType::get(Ty, NumPadBytes);
+
+ Elts.push_back(llvm::UndefValue::get(Ty));
+ Types.push_back(Ty);
+ }
+
+ llvm::StructType* STy =
+ llvm::StructType::get(C->getType()->getContext(), Types, false);
+ return llvm::ConstantStruct::get(STy, Elts);
+ }
+ case CastExpr::CK_NullToMemberPointer:
+ return CGM.EmitNullConstant(E->getType());
+
+ case CastExpr::CK_BaseToDerivedMemberPointer: {
+ Expr *SubExpr = E->getSubExpr();
+
+ const MemberPointerType *SrcTy =
+ SubExpr->getType()->getAs<MemberPointerType>();
+ const MemberPointerType *DestTy =
+ E->getType()->getAs<MemberPointerType>();
+
+ const CXXRecordDecl *BaseClass =
+ cast<CXXRecordDecl>(cast<RecordType>(SrcTy->getClass())->getDecl());
+ const CXXRecordDecl *DerivedClass =
+ cast<CXXRecordDecl>(cast<RecordType>(DestTy->getClass())->getDecl());
+
+ if (SrcTy->getPointeeType()->isFunctionProtoType()) {
+ llvm::Constant *C =
+ CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF);
+ if (!C)
+ return 0;
+
+ llvm::ConstantStruct *CS = cast<llvm::ConstantStruct>(C);
+
+ // Check if we need to update the adjustment.
+ if (llvm::Constant *Offset =
+ CGM.GetNonVirtualBaseClassOffset(DerivedClass, BaseClass)) {
+ llvm::Constant *Values[2];
+
+ Values[0] = CS->getOperand(0);
+ Values[1] = llvm::ConstantExpr::getAdd(CS->getOperand(1), Offset);
+ return llvm::ConstantStruct::get(CGM.getLLVMContext(), Values, 2,
+ /*Packed=*/false);
+ }
+
+ return CS;
+ }
+ }
+
+ case CastExpr::CK_BitCast:
+ // This must be a member function pointer cast.
+ return Visit(E->getSubExpr());
+
+ default: {
+ // FIXME: This should be handled by the CK_NoOp cast kind.
+ // Explicit and implicit no-op casts
+ QualType Ty = E->getType(), SubTy = E->getSubExpr()->getType();
+ if (CGM.getContext().hasSameUnqualifiedType(Ty, SubTy))
+ return Visit(E->getSubExpr());
+
+ // Handle integer->integer casts for address-of-label differences.
+ if (Ty->isIntegerType() && SubTy->isIntegerType() &&
+ CGF) {
+ llvm::Value *Src = Visit(E->getSubExpr());
+ if (Src == 0) return 0;
+
+ // Use EmitScalarConversion to perform the conversion.
+ return cast<llvm::Constant>(CGF->EmitScalarConversion(Src, SubTy, Ty));
+ }
+
+ return 0;
+ }
+ }
+ }
+
+ llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
+ return Visit(DAE->getExpr());
+ }
+
+ llvm::Constant *EmitArrayInitialization(InitListExpr *ILE) {
+ std::vector<llvm::Constant*> Elts;
+ const llvm::ArrayType *AType =
+ cast<llvm::ArrayType>(ConvertType(ILE->getType()));
+ unsigned NumInitElements = ILE->getNumInits();
+ // FIXME: Check for wide strings
+ // FIXME: Check for NumInitElements exactly equal to 1??
+ if (NumInitElements > 0 &&
+ (isa<StringLiteral>(ILE->getInit(0)) ||
+ isa<ObjCEncodeExpr>(ILE->getInit(0))) &&
+ ILE->getType()->getArrayElementTypeNoTypeQual()->isCharType())
+ return Visit(ILE->getInit(0));
+ const llvm::Type *ElemTy = AType->getElementType();
+ unsigned NumElements = AType->getNumElements();
+
+ // Initialising an array requires us to automatically
+ // initialise any elements that have not been initialised explicitly
+ unsigned NumInitableElts = std::min(NumInitElements, NumElements);
+
+ // Copy initializer elements.
+ unsigned i = 0;
+ bool RewriteType = false;
+ for (; i < NumInitableElts; ++i) {
+ Expr *Init = ILE->getInit(i);
+ llvm::Constant *C = CGM.EmitConstantExpr(Init, Init->getType(), CGF);
+ if (!C)
+ return 0;
+ RewriteType |= (C->getType() != ElemTy);
+ Elts.push_back(C);
+ }
+
+ // Initialize remaining array elements.
+ // FIXME: This doesn't handle member pointers correctly!
+ for (; i < NumElements; ++i)
+ Elts.push_back(llvm::Constant::getNullValue(ElemTy));
+
+ if (RewriteType) {
+ // FIXME: Try to avoid packing the array
+ std::vector<const llvm::Type*> Types;
+ for (unsigned i = 0; i < Elts.size(); ++i)
+ Types.push_back(Elts[i]->getType());
+ const llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
+ Types, true);
+ return llvm::ConstantStruct::get(SType, Elts);
+ }
+
+ return llvm::ConstantArray::get(AType, Elts);
+ }
+
+ llvm::Constant *EmitStructInitialization(InitListExpr *ILE) {
+ return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
+ }
+
+ llvm::Constant *EmitUnionInitialization(InitListExpr *ILE) {
+ return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
+ }
+
+ llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E) {
+ return CGM.EmitNullConstant(E->getType());
+ }
+
+ llvm::Constant *VisitInitListExpr(InitListExpr *ILE) {
+ if (ILE->getType()->isScalarType()) {
+ // We have a scalar in braces. Just use the first element.
+ if (ILE->getNumInits() > 0) {
+ Expr *Init = ILE->getInit(0);
+ return CGM.EmitConstantExpr(Init, Init->getType(), CGF);
+ }
+ return CGM.EmitNullConstant(ILE->getType());
+ }
+
+ if (ILE->getType()->isArrayType())
+ return EmitArrayInitialization(ILE);
+
+ if (ILE->getType()->isRecordType())
+ return EmitStructInitialization(ILE);
+
+ if (ILE->getType()->isUnionType())
+ return EmitUnionInitialization(ILE);
+
+ // If ILE was a constant vector, we would have handled it already.
+ if (ILE->getType()->isVectorType())
+ return 0;
+
+ assert(0 && "Unable to handle InitListExpr");
+ // Get rid of control reaches end of void function warning.
+ // Not reached.
+ return 0;
+ }
+
+ llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E) {
+ if (!E->getConstructor()->isTrivial())
+ return 0;
+
+ QualType Ty = E->getType();
+
+ // FIXME: We should not have to call getBaseElementType here.
+ const RecordType *RT =
+ CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
+ const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+
+ // If the class doesn't have a trivial destructor, we can't emit it as a
+ // constant expr.
+ if (!RD->hasTrivialDestructor())
+ return 0;
+
+ // Only copy and default constructors can be trivial.
+
+
+ if (E->getNumArgs()) {
+ assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
+ assert(E->getConstructor()->isCopyConstructor() &&
+ "trivial ctor has argument but isn't a copy ctor");
+
+ Expr *Arg = E->getArg(0);
+ assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
+ "argument to copy ctor is of wrong type");
+
+ return Visit(Arg);
+ }
+
+ return CGM.EmitNullConstant(Ty);
+ }
+
+ llvm::Constant *VisitStringLiteral(StringLiteral *E) {
+ assert(!E->getType()->isPointerType() && "Strings are always arrays");
+
+ // This must be a string initializing an array in a static initializer.
+ // Don't emit it as the address of the string, emit the string data itself
+ // as an inline array.
+ return llvm::ConstantArray::get(VMContext,
+ CGM.GetStringForStringLiteral(E), false);
+ }
+
+ llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E) {
+ // This must be an @encode initializing an array in a static initializer.
+ // Don't emit it as the address of the string, emit the string data itself
+ // as an inline array.
+ std::string Str;
+ CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
+ const ConstantArrayType *CAT = cast<ConstantArrayType>(E->getType());
+
+ // Resize the string to the right size, adding zeros at the end, or
+ // truncating as needed.
+ Str.resize(CAT->getSize().getZExtValue(), '\0');
+ return llvm::ConstantArray::get(VMContext, Str, false);
+ }
+
+ llvm::Constant *VisitUnaryExtension(const UnaryOperator *E) {
+ return Visit(E->getSubExpr());
+ }
+
+ // Utility methods
+ const llvm::Type *ConvertType(QualType T) {
+ return CGM.getTypes().ConvertType(T);
+ }
+
+public:
+ llvm::Constant *EmitLValue(Expr *E) {
+ switch (E->getStmtClass()) {
+ default: break;
+ case Expr::CompoundLiteralExprClass: {
+ // Note that due to the nature of compound literals, this is guaranteed
+ // to be the only use of the variable, so we just generate it here.
+ CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
+ llvm::Constant* C = Visit(CLE->getInitializer());
+ // FIXME: "Leaked" on failure.
+ if (C)
+ C = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
+ E->getType().isConstant(CGM.getContext()),
+ llvm::GlobalValue::InternalLinkage,
+ C, ".compoundliteral", 0, false,
+ E->getType().getAddressSpace());
+ return C;
+ }
+ case Expr::DeclRefExprClass: {
+ NamedDecl *Decl = cast<DeclRefExpr>(E)->getDecl();
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Decl))
+ return CGM.GetAddrOfFunction(FD);
+ if (const VarDecl* VD = dyn_cast<VarDecl>(Decl)) {
+ // We can never refer to a variable with local storage.
+ if (!VD->hasLocalStorage()) {
+ if (VD->isFileVarDecl() || VD->hasExternalStorage())
+ return CGM.GetAddrOfGlobalVar(VD);
+ else if (VD->isBlockVarDecl()) {
+ assert(CGF && "Can't access static local vars without CGF");
+ return CGF->GetAddrOfStaticLocalVar(VD);
+ }
+ }
+ }
+ break;
+ }
+ case Expr::StringLiteralClass:
+ return CGM.GetAddrOfConstantStringFromLiteral(cast<StringLiteral>(E));
+ case Expr::ObjCEncodeExprClass:
+ return CGM.GetAddrOfConstantStringFromObjCEncode(cast<ObjCEncodeExpr>(E));
+ case Expr::ObjCStringLiteralClass: {
+ ObjCStringLiteral* SL = cast<ObjCStringLiteral>(E);
+ llvm::Constant *C =
+ CGM.getObjCRuntime().GenerateConstantString(SL->getString());
+ return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
+ }
+ case Expr::PredefinedExprClass: {
+ unsigned Type = cast<PredefinedExpr>(E)->getIdentType();
+ if (CGF) {
+ LValue Res = CGF->EmitPredefinedFunctionName(Type);
+ return cast<llvm::Constant>(Res.getAddress());
+ } else if (Type == PredefinedExpr::PrettyFunction) {
+ return CGM.GetAddrOfConstantCString("top level", ".tmp");
+ }
+
+ return CGM.GetAddrOfConstantCString("", ".tmp");
+ }
+ case Expr::AddrLabelExprClass: {
+ assert(CGF && "Invalid address of label expression outside function.");
+ llvm::Constant *Ptr =
+ CGF->GetAddrOfLabel(cast<AddrLabelExpr>(E)->getLabel());
+ return llvm::ConstantExpr::getBitCast(Ptr, ConvertType(E->getType()));
+ }
+ case Expr::CallExprClass: {
+ CallExpr* CE = cast<CallExpr>(E);
+ unsigned builtin = CE->isBuiltinCall(CGM.getContext());
+ if (builtin !=
+ Builtin::BI__builtin___CFStringMakeConstantString &&
+ builtin !=
+ Builtin::BI__builtin___NSStringMakeConstantString)
+ break;
+ const Expr *Arg = CE->getArg(0)->IgnoreParenCasts();
+ const StringLiteral *Literal = cast<StringLiteral>(Arg);
+ if (builtin ==
+ Builtin::BI__builtin___NSStringMakeConstantString) {
+ return CGM.getObjCRuntime().GenerateConstantString(Literal);
+ }
+ // FIXME: need to deal with UCN conversion issues.
+ return CGM.GetAddrOfConstantCFString(Literal);
+ }
+ case Expr::BlockExprClass: {
+ std::string FunctionName;
+ if (CGF)
+ FunctionName = CGF->CurFn->getName();
+ else
+ FunctionName = "global";
+
+ return CGM.GetAddrOfGlobalBlock(cast<BlockExpr>(E), FunctionName.c_str());
+ }
+ }
+
+ return 0;
+ }
+};
+
+} // end anonymous namespace.
+
+llvm::Constant *CodeGenModule::EmitConstantExpr(const Expr *E,
+ QualType DestType,
+ CodeGenFunction *CGF) {
+ Expr::EvalResult Result;
+
+ bool Success = false;
+
+ if (DestType->isReferenceType())
+ Success = E->EvaluateAsLValue(Result, Context);
+ else
+ Success = E->Evaluate(Result, Context);
+
+ if (Success && !Result.HasSideEffects) {
+ switch (Result.Val.getKind()) {
+ case APValue::Uninitialized:
+ assert(0 && "Constant expressions should be initialized.");
+ return 0;
+ case APValue::LValue: {
+ const llvm::Type *DestTy = getTypes().ConvertTypeForMem(DestType);
+ llvm::Constant *Offset =
+ llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext),
+ Result.Val.getLValueOffset().getQuantity());
+
+ llvm::Constant *C;
+ if (const Expr *LVBase = Result.Val.getLValueBase()) {
+ C = ConstExprEmitter(*this, CGF).EmitLValue(const_cast<Expr*>(LVBase));
+
+ // Apply offset if necessary.
+ if (!Offset->isNullValue()) {
+ const llvm::Type *Type = llvm::Type::getInt8PtrTy(VMContext);
+ llvm::Constant *Casted = llvm::ConstantExpr::getBitCast(C, Type);
+ Casted = llvm::ConstantExpr::getGetElementPtr(Casted, &Offset, 1);
+ C = llvm::ConstantExpr::getBitCast(Casted, C->getType());
+ }
+
+ // Convert to the appropriate type; this could be an lvalue for
+ // an integer.
+ if (isa<llvm::PointerType>(DestTy))
+ return llvm::ConstantExpr::getBitCast(C, DestTy);
+
+ return llvm::ConstantExpr::getPtrToInt(C, DestTy);
+ } else {
+ C = Offset;
+
+ // Convert to the appropriate type; this could be an lvalue for
+ // an integer.
+ if (isa<llvm::PointerType>(DestTy))
+ return llvm::ConstantExpr::getIntToPtr(C, DestTy);
+
+ // If the types don't match this should only be a truncate.
+ if (C->getType() != DestTy)
+ return llvm::ConstantExpr::getTrunc(C, DestTy);
+
+ return C;
+ }
+ }
+ case APValue::Int: {
+ llvm::Constant *C = llvm::ConstantInt::get(VMContext,
+ Result.Val.getInt());
+
+ if (C->getType() == llvm::Type::getInt1Ty(VMContext)) {
+ const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType());
+ C = llvm::ConstantExpr::getZExt(C, BoolTy);
+ }
+ return C;
+ }
+ case APValue::ComplexInt: {
+ llvm::Constant *Complex[2];
+
+ Complex[0] = llvm::ConstantInt::get(VMContext,
+ Result.Val.getComplexIntReal());
+ Complex[1] = llvm::ConstantInt::get(VMContext,
+ Result.Val.getComplexIntImag());
+
+ // FIXME: the target may want to specify that this is packed.
+ return llvm::ConstantStruct::get(VMContext, Complex, 2, false);
+ }
+ case APValue::Float:
+ return llvm::ConstantFP::get(VMContext, Result.Val.getFloat());
+ case APValue::ComplexFloat: {
+ llvm::Constant *Complex[2];
+
+ Complex[0] = llvm::ConstantFP::get(VMContext,
+ Result.Val.getComplexFloatReal());
+ Complex[1] = llvm::ConstantFP::get(VMContext,
+ Result.Val.getComplexFloatImag());
+
+ // FIXME: the target may want to specify that this is packed.
+ return llvm::ConstantStruct::get(VMContext, Complex, 2, false);
+ }
+ case APValue::Vector: {
+ llvm::SmallVector<llvm::Constant *, 4> Inits;
+ unsigned NumElts = Result.Val.getVectorLength();
+
+ for (unsigned i = 0; i != NumElts; ++i) {
+ APValue &Elt = Result.Val.getVectorElt(i);
+ if (Elt.isInt())
+ Inits.push_back(llvm::ConstantInt::get(VMContext, Elt.getInt()));
+ else
+ Inits.push_back(llvm::ConstantFP::get(VMContext, Elt.getFloat()));
+ }
+ return llvm::ConstantVector::get(&Inits[0], Inits.size());
+ }
+ }
+ }
+
+ llvm::Constant* C = ConstExprEmitter(*this, CGF).Visit(const_cast<Expr*>(E));
+ if (C && C->getType() == llvm::Type::getInt1Ty(VMContext)) {
+ const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType());
+ C = llvm::ConstantExpr::getZExt(C, BoolTy);
+ }
+ return C;
+}
+
+static bool containsPointerToDataMember(CodeGenTypes &Types, QualType T) {
+ // No need to check for member pointers when not compiling C++.
+ if (!Types.getContext().getLangOptions().CPlusPlus)
+ return false;
+
+ T = Types.getContext().getBaseElementType(T);
+
+ if (const RecordType *RT = T->getAs<RecordType>()) {
+ const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+
+ // FIXME: It would be better if there was a way to explicitly compute the
+ // record layout instead of converting to a type.
+ Types.ConvertTagDeclType(RD);
+
+ const CGRecordLayout &Layout = Types.getCGRecordLayout(RD);
+ return Layout.containsPointerToDataMember();
+ }
+
+ if (const MemberPointerType *MPT = T->getAs<MemberPointerType>())
+ return !MPT->getPointeeType()->isFunctionType();
+
+ return false;
+}
+
+llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
+ if (!containsPointerToDataMember(getTypes(), T))
+ return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
+
+ if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
+
+ QualType ElementTy = CAT->getElementType();
+
+ llvm::Constant *Element = EmitNullConstant(ElementTy);
+ unsigned NumElements = CAT->getSize().getZExtValue();
+ std::vector<llvm::Constant *> Array(NumElements);
+ for (unsigned i = 0; i != NumElements; ++i)
+ Array[i] = Element;
+
+ const llvm::ArrayType *ATy =
+ cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
+ return llvm::ConstantArray::get(ATy, Array);
+ }
+
+ if (const RecordType *RT = T->getAs<RecordType>()) {
+ const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+ assert(!RD->getNumBases() &&
+ "FIXME: Handle zero-initializing structs with bases and "
+ "pointers to data members.");
+ const llvm::StructType *STy =
+ cast<llvm::StructType>(getTypes().ConvertTypeForMem(T));
+ unsigned NumElements = STy->getNumElements();
+ std::vector<llvm::Constant *> Elements(NumElements);
+
+ for (RecordDecl::field_iterator I = RD->field_begin(),
+ E = RD->field_end(); I != E; ++I) {
+ const FieldDecl *FD = *I;
+
+ unsigned FieldNo = getTypes().getLLVMFieldNo(FD);
+ Elements[FieldNo] = EmitNullConstant(FD->getType());
+ }
+
+ // Now go through all other fields and zero them out.
+ for (unsigned i = 0; i != NumElements; ++i) {
+ if (!Elements[i])
+ Elements[i] = llvm::Constant::getNullValue(STy->getElementType(i));
+ }
+
+ return llvm::ConstantStruct::get(STy, Elements);
+ }
+
+ assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() &&
+ "Should only see pointers to data members here!");
+
+ // Itanium C++ ABI 2.3:
+ // A NULL pointer is represented as -1.
+ return llvm::ConstantInt::get(getTypes().ConvertTypeForMem(T), -1,
+ /*isSigned=*/true);
+}
+
+llvm::Constant *
+CodeGenModule::EmitPointerToDataMember(const FieldDecl *FD) {
+
+ // Itanium C++ ABI 2.3:
+ // A pointer to data member is an offset from the base address of the class
+ // object containing it, represented as a ptrdiff_t
+
+ const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(FD->getParent());
+ QualType ClassType =
+ getContext().getTypeDeclType(const_cast<CXXRecordDecl *>(ClassDecl));
+
+ const llvm::StructType *ClassLTy =
+ cast<llvm::StructType>(getTypes().ConvertType(ClassType));
+
+ unsigned FieldNo = getTypes().getLLVMFieldNo(FD);
+ uint64_t Offset =
+ getTargetData().getStructLayout(ClassLTy)->getElementOffset(FieldNo);
+
+ const llvm::Type *PtrDiffTy =
+ getTypes().ConvertType(getContext().getPointerDiffType());
+
+ return llvm::ConstantInt::get(PtrDiffTy, Offset);
+}