diff options
| -rw-r--r-- | clang/lib/CodeGen/CGExprConstant.cpp | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp index bf8123648bb..0e9d20928c7 100644 --- a/clang/lib/CodeGen/CGExprConstant.cpp +++ b/clang/lib/CodeGen/CGExprConstant.cpp @@ -378,9 +378,35 @@ public: if (E->getType()->isUnionType()) { const llvm::Type *Ty = ConvertType(E->getType()); Expr *SubExpr = E->getSubExpr(); - return EmitUnion(CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF), - Ty); + + 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::Int8Ty; + if (NumPadBytes > 1) + Ty = llvm::ArrayType::get(Ty, NumPadBytes); + + Elts.push_back(llvm::Constant::getNullValue(Ty)); + Types.push_back(Ty); + } + + llvm::StructType* STy = llvm::StructType::get(Types, false); + return llvm::ConstantStruct::get(STy, Elts); } + // Explicit and implicit no-op casts QualType Ty = E->getType(), SubTy = E->getSubExpr()->getType(); if (CGM.getContext().hasSameUnqualifiedType(Ty, SubTy)) { |
