[COFF, ARM64] Fix ABI implementation of struct returns
Summary:
Related llvm patch: D60348.
Patch co-authored by Sanjin Sijaric.
Reviewers: rnk, efriedma, TomTan, ssijaric, ostannard
Reviewed By: efriedma
Subscribers: dmajor, richard.townsend.arm, ostannard, javed.absar, kristof.beyls, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D60349
llvm-svn: 359932
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index b837fa4..bc9be14 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/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);
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index fba5490..c37bfe3 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -1051,33 +1051,55 @@
return isDeletingDtor(GD);
}
+static bool IsSizeGreaterThan128(const CXXRecordDecl *RD) {
+ return RD->getASTContext().getTypeSize(RD->getTypeForDecl()) > 128;
+}
+
+static bool hasMicrosoftABIRestrictions(const CXXRecordDecl *RD) {
+ // For AArch64, we use the C++14 definition of an aggregate, so we also
+ // check for:
+ // No private or protected non static data members.
+ // No base classes
+ // No virtual functions
+ // Additionally, we need to ensure that there is a trivial copy assignment
+ // operator, a trivial destructor and no user-provided constructors.
+ if (RD->hasProtectedFields() || RD->hasPrivateFields())
+ return true;
+ if (RD->getNumBases() > 0)
+ return true;
+ if (RD->isPolymorphic())
+ return true;
+ if (RD->hasNonTrivialCopyAssignment())
+ return true;
+ for (const CXXConstructorDecl *Ctor : RD->ctors())
+ if (Ctor->isUserProvided())
+ return true;
+ if (RD->hasNonTrivialDestructor())
+ return true;
+ return false;
+}
+
bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
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 isAArch64 = CGM.getTarget().getTriple().isAArch64();
+ bool isSimple = !isAArch64 || !hasMicrosoftABIRestrictions(RD);
+ bool isIndirectReturn =
+ isAArch64 ? (!RD->canPassInRegisters() ||
+ IsSizeGreaterThan128(RD))
+ : !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.
+ if (isIndirectReturn || !isSimple || isInstanceMethod) {
+ CharUnits Align = CGM.getContext().getTypeAlignInChars(FI.getReturnType());
FI.getReturnInfo() = ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
+ FI.getReturnInfo().setSRetAfterThis(isInstanceMethod);
- // 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);
+ FI.getReturnInfo().setInReg(isAArch64 &&
+ !(isSimple && IsSizeGreaterThan128(RD)));
+
return true;
}
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 2e7573d..b90ab04 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -5957,8 +5957,11 @@
// Note: This permits small classes with nontrivial destructors to be
// passed in registers, which is non-conforming.
+ bool isAArch64 = S.Context.getTargetInfo().getTriple().isAArch64();
+ uint64_t TypeSize = isAArch64 ? 128 : 64;
+
if (CopyCtorIsTrivial &&
- S.getASTContext().getTypeSize(D->getTypeForDecl()) <= 64)
+ S.getASTContext().getTypeSize(D->getTypeForDecl()) <= TypeSize)
return true;
return false;
}