x86-32 Darwin ABI: Handle small structures correctly.
- Small structures are returned in a register if:
1. They fit nicely in a register.
2. All fields fit nicely in a register.
(more or less)
- We now pass the first 5000 ABITests if unions are disabled.
- <rdar://problem/6497882> [irgen] x86-32 ABI compatibility with
small structs
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68197 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 945d52f..4db36d9 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -262,6 +262,8 @@
return (Size == 8 || Size == 16 || Size == 32 || Size == 64);
}
+ static bool shouldReturnTypeInRegister(QualType Ty, ASTContext &Context);
+
public:
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context) const;
@@ -283,6 +285,60 @@
};
}
+
+/// shouldReturnTypeInRegister - Determine if the given type should be
+/// passed in a register (for the Darwin ABI).
+bool X86_32ABIInfo::shouldReturnTypeInRegister(QualType Ty,
+ ASTContext &Context) {
+ uint64_t Size = Context.getTypeSize(Ty);
+
+ // Type must be register sized.
+ if (!isRegisterSize(Size))
+ return false;
+
+ if (Ty->isVectorType()) {
+ // 64- and 128- bit vectors inside structures are not returned in
+ // registers.
+ if (Size == 64 || Size == 128)
+ return false;
+
+ return true;
+ }
+
+ // If this is a builtin, pointer, or complex type, it is ok.
+ if (Ty->getAsBuiltinType() || Ty->isPointerType() || Ty->isAnyComplexType())
+ return true;
+
+ // Arrays are treated like records.
+ if (const ConstantArrayType *AT = Context.getAsConstantArrayType(Ty))
+ return shouldReturnTypeInRegister(AT->getElementType(), Context);
+
+ // Otherwise, it must be a record type.
+ const RecordType *RT = Ty->getAsRecordType();
+ if (!RT) return false;
+
+ // Structure types are passed in register if all fields would be
+ // passed in a register.
+ for (RecordDecl::field_iterator i = RT->getDecl()->field_begin(),
+ e = RT->getDecl()->field_end(); i != e; ++i) {
+ const FieldDecl *FD = *i;
+
+ // FIXME: Reject bitfields wholesale for now; this is incorrect.
+ if (FD->isBitField())
+ return false;
+
+ // Empty structures are ignored.
+ if (isEmptyRecord(FD->getType()))
+ continue;
+
+ // Check fields recursively.
+ if (!shouldReturnTypeInRegister(FD->getType(), Context))
+ return false;
+ }
+
+ return true;
+}
+
ABIArgInfo X86_32ABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context) const {
if (RetTy->isVoidType()) {
@@ -345,8 +401,18 @@
}
uint64_t Size = Context.getTypeSize(RetTy);
- if (isRegisterSize(Size))
- return ABIArgInfo::getCoerce(llvm::IntegerType::get(Size));
+ if (isRegisterSize(Size)) {
+ // Always return in register for unions for now.
+ // FIXME: This is wrong, but better than treating as a
+ // structure.
+ if (RetTy->isUnionType())
+ return ABIArgInfo::getCoerce(llvm::IntegerType::get(Size));
+
+ // Small structures which are register sized are generally returned
+ // in a register.
+ if (X86_32ABIInfo::shouldReturnTypeInRegister(RetTy, Context))
+ return ABIArgInfo::getCoerce(llvm::IntegerType::get(Size));
+ }
return ABIArgInfo::getIndirect(0);
} else {