mgrang updated this revision to Diff 194954.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D60349/new/
https://reviews.llvm.org/D60349
Files:
include/clang/CodeGen/CGFunctionInfo.h
lib/CodeGen/CGCall.cpp
lib/CodeGen/MicrosoftCXXABI.cpp
test/CodeGen/arm64-microsoft-arguments.cpp
Index: test/CodeGen/arm64-microsoft-arguments.cpp
===================================================================
--- test/CodeGen/arm64-microsoft-arguments.cpp
+++ test/CodeGen/arm64-microsoft-arguments.cpp
@@ -14,7 +14,7 @@
struct pod bar() { return s; }
struct non_pod foo() { return t; }
// CHECK: define {{.*}} void @{{.*}}bar{{.*}}(%struct.pod* noalias sret %agg.result)
-// CHECK: define {{.*}} void @{{.*}}foo{{.*}}(%struct.non_pod* noalias %agg.result)
+// CHECK: define {{.*}} void @{{.*}}foo{{.*}}(%struct.non_pod* inreg noalias sret %agg.result)
// Check instance methods.
@@ -22,4 +22,4 @@
struct Baz { pod2 baz(); };
int qux() { return Baz().baz().x; }
-// CHECK: declare {{.*}} void @{{.*}}baz@Baz{{.*}}(%struct.Baz*, %struct.pod2*)
+// CHECK: declare {{.*}} void @{{.*}}baz@Baz{{.*}}(%struct.Baz*, %struct.pod2* sret)
Index: lib/CodeGen/MicrosoftCXXABI.cpp
===================================================================
--- lib/CodeGen/MicrosoftCXXABI.cpp
+++ lib/CodeGen/MicrosoftCXXABI.cpp
@@ -1052,32 +1052,43 @@
}
bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
+ // For AArch64 see:
+ // https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=vs-2019#return-values
+
+ // 1. For return types <= 16 bytes, use the C return semantics.
+
+ // 2. For instance methods, "this" is passed to the callee in X0 and the
+ // struct address in X1. So the callee needs to copy X1 to X0 before
+ // returning.
+
+ // 3. For non-instance methods which return a non-POD struct, the address of
+ // the struct is passed to the callee in X0. We use the "inreg" attribute on
+ // a parameter to indicate a non-POD struct.
+
+ // 4. Example of POD struct: struct pod { int x; }
+ // Example of non-POD struct: struct nonpod { int x; nonpod() {} }
+
+ bool isAArch64 = CGM.getTarget().getTriple().isAArch64();
+
+ if (isAArch64) {
+ uint64_t RetTySize = getContext().getTypeSize(FI.getReturnType());
+ if (RetTySize <= 16)
+ return false;
+ }
+
const CXXRecordDecl *RD = FI.getReturnType()->getAsCXXRecordDecl();
if (!RD)
return false;
- CharUnits Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType());
- if (FI.isInstanceMethod()) {
- // If it's an instance method, aggregates are always returned indirectly via
- // the second parameter.
- FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
- FI.getReturnInfo().setSRetAfterThis(FI.isInstanceMethod());
+ bool isIndirectReturn = !RD->isPOD();
+ bool isInstanceMethod = FI.isInstanceMethod();
- // aarch64-windows requires that instance methods use X1 for the return
- // address. So for aarch64-windows we do not mark the
- // return as SRet.
- FI.getReturnInfo().setSuppressSRet(CGM.getTarget().getTriple().getArch() ==
- llvm::Triple::aarch64);
- return true;
- } else if (!RD->isPOD()) {
- // If it's a free function, non-POD types are returned indirectly.
+ CharUnits Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType());
+ if (isIndirectReturn || isInstanceMethod) {
FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
+ FI.getReturnInfo().setSRetAfterThis(isInstanceMethod);
+ FI.getReturnInfo().setInReg(isAArch64 && isIndirectReturn);
- // aarch64-windows requires that non-POD, non-instance returns use X0 for
- // the return address. So for aarch64-windows we do not mark the return as
- // SRet.
- FI.getReturnInfo().setSuppressSRet(CGM.getTarget().getTriple().getArch() ==
- llvm::Triple::aarch64);
return true;
}
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1999,8 +1999,7 @@
// Attach attributes to sret.
if (IRFunctionArgs.hasSRetArg()) {
llvm::AttrBuilder SRETAttrs;
- if (!RetAI.getSuppressSRet())
- SRETAttrs.addAttribute(llvm::Attribute::StructRet);
+ SRETAttrs.addAttribute(llvm::Attribute::StructRet);
hasUsedSRet = true;
if (RetAI.getInReg())
SRETAttrs.addAttribute(llvm::Attribute::InReg);
Index: include/clang/CodeGen/CGFunctionInfo.h
===================================================================
--- include/clang/CodeGen/CGFunctionInfo.h
+++ include/clang/CodeGen/CGFunctionInfo.h
@@ -95,7 +95,6 @@
bool InReg : 1; // isDirect() || isExtend() || isIndirect()
bool CanBeFlattened: 1; // isDirect()
bool SignExt : 1; // isExtend()
- bool SuppressSRet : 1; // isIndirect()
bool canHavePaddingType() const {
return isDirect() || isExtend() || isIndirect() || isExpand();
@@ -111,14 +110,13 @@
}
ABIArgInfo(Kind K)
- : TheKind(K), PaddingInReg(false), InReg(false), SuppressSRet(false) {
+ : TheKind(K), PaddingInReg(false), InReg(false) {
}
public:
ABIArgInfo()
: TypeData(nullptr), PaddingType(nullptr), DirectOffset(0),
- TheKind(Direct), PaddingInReg(false), InReg(false),
- SuppressSRet(false) {}
+ TheKind(Direct), PaddingInReg(false), InReg(false) {}
static ABIArgInfo getDirect(llvm::Type *T = nullptr, unsigned Offset = 0,
llvm::Type *Padding = nullptr,
@@ -407,16 +405,6 @@
CanBeFlattened = Flatten;
}
- bool getSuppressSRet() const {
- assert(isIndirect() && "Invalid kind!");
- return SuppressSRet;
- }
-
- void setSuppressSRet(bool Suppress) {
- assert(isIndirect() && "Invalid kind!");
- SuppressSRet = Suppress;
- }
-
void dump() const;
};
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