Fix PR2101 - Codegen crash during bitfield initialization.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50769 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenTypes.cpp b/lib/CodeGen/CodeGenTypes.cpp
index a7f6670..751cd3a 100644
--- a/lib/CodeGen/CodeGenTypes.cpp
+++ b/lib/CodeGen/CodeGenTypes.cpp
@@ -521,7 +521,28 @@
unsigned StructAlign = RL.getAlignment();
if (llvmSize % StructAlign) {
unsigned StructPadding = StructAlign - (llvmSize % StructAlign);
- addPaddingFields(llvmSize + StructPadding);
+ bool needStructPadding = true;
+ if (!LLVMFields.empty()) {
+ const llvm::Type *LastFieldType = LLVMFields.back();
+ const llvm::Type *LastFieldDeclType =
+ CGT.ConvertTypeRecursive(FieldDecls.back()->getType());
+ if (LastFieldType != LastFieldDeclType) {
+ unsigned LastFieldTypeSize =
+ CGT.getTargetData().getABITypeSizeInBits(LastFieldType);
+ unsigned LastFieldDeclTypeSize =
+ CGT.getTargetData().getABITypeSizeInBits(LastFieldDeclType);
+ if (LastFieldDeclTypeSize > LastFieldTypeSize
+ && StructPadding == (LastFieldDeclTypeSize - LastFieldTypeSize)) {
+ // Replace last LLVMField with a LastFieldDeclType field will
+ // to avoid extra padding fields.
+ LLVMFields.pop_back();
+ LLVMFields.push_back(LastFieldDeclType);
+ needStructPadding = false;
+ }
+ }
+ }
+ if (needStructPadding)
+ addPaddingFields(llvmSize + StructPadding);
}
STy = llvm::StructType::get(LLVMFields);
@@ -533,8 +554,13 @@
assert(WaterMark >= llvmSize && "Invalid padding Field");
unsigned RequiredBits = WaterMark - llvmSize;
unsigned RequiredBytes = (RequiredBits + 7) / 8;
- for (unsigned i = 0; i != RequiredBytes; ++i)
- addLLVMField(llvm::Type::Int8Ty, true);
+ if (RequiredBytes == 1)
+ // This is a bitfield that is using few bits from this byte.
+ // It is not a padding field.
+ addLLVMField(llvm::Type::Int8Ty, false);
+ else
+ for (unsigned i = 0; i != RequiredBytes; ++i)
+ addLLVMField(llvm::Type::Int8Ty, true);
}
/// addLLVMField - Add llvm struct field that corresponds to llvm type Ty.
diff --git a/test/CodeGen/bitfield-init.c b/test/CodeGen/bitfield-init.c
new file mode 100644
index 0000000..6e89e11
--- /dev/null
+++ b/test/CodeGen/bitfield-init.c
@@ -0,0 +1,4 @@
+// RUN: clang %s -emit-llvm
+typedef struct { unsigned int i: 1; } c;
+const c d = { 1 };
+