[llvm-branch-commits] [clang] e5f51fd - [clang][aarch64] Precondition isHomogeneousAggregate on isCXX14Aggregate
David Truby via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Jan 12 11:50:57 PST 2021
Author: David Truby
Date: 2021-01-12T19:44:01Z
New Revision: e5f51fdd650c6d20c81fedb8e856e9858aa10991
URL: https://github.com/llvm/llvm-project/commit/e5f51fdd650c6d20c81fedb8e856e9858aa10991
DIFF: https://github.com/llvm/llvm-project/commit/e5f51fdd650c6d20c81fedb8e856e9858aa10991.diff
LOG: [clang][aarch64] Precondition isHomogeneousAggregate on isCXX14Aggregate
MSVC on WoA64 includes isCXX14Aggregate in its definition. This is de-facto
specification on that platform, so match msvc's behaviour.
Fixes: https://bugs.llvm.org/show_bug.cgi?id=47611
Co-authored-by: Peter Waller <peter.waller at arm.com>
Differential Revision: https://reviews.llvm.org/D92751
Added:
Modified:
clang/lib/CodeGen/CGCXXABI.h
clang/lib/CodeGen/MicrosoftCXXABI.cpp
clang/lib/CodeGen/TargetInfo.cpp
clang/test/CodeGenCXX/homogeneous-aggregates.cpp
llvm/test/CodeGen/AArch64/arm64-windows-calls.ll
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGCXXABI.h b/clang/lib/CodeGen/CGCXXABI.h
index 171428a3525d..ea839db7528e 100644
--- a/clang/lib/CodeGen/CGCXXABI.h
+++ b/clang/lib/CodeGen/CGCXXABI.h
@@ -146,6 +146,13 @@ class CGCXXABI {
/// 'this' parameter of C++ instance methods.
virtual bool isSRetParameterAfterThis() const { return false; }
+ /// Returns true if the ABI permits the argument to be a homogeneous
+ /// aggregate.
+ virtual bool
+ isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const {
+ return true;
+ };
+
/// Find the LLVM type used to represent the given member pointer
/// type.
virtual llvm::Type *
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index c16c72dc93d5..cb0dc1d5d717 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -771,6 +771,9 @@ class MicrosoftCXXABI : public CGCXXABI {
LoadVTablePtr(CodeGenFunction &CGF, Address This,
const CXXRecordDecl *RD) override;
+ virtual bool
+ isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const override;
+
private:
typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VTablesMapTy;
@@ -1070,7 +1073,7 @@ bool MicrosoftCXXABI::hasMostDerivedReturn(GlobalDecl GD) const {
return isDeletingDtor(GD);
}
-static bool isCXX14Aggregate(const CXXRecordDecl *RD) {
+static bool isTrivialForAArch64MSVC(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.
@@ -1107,7 +1110,7 @@ bool MicrosoftCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
bool isTrivialForABI = RD->isPOD();
bool isAArch64 = CGM.getTarget().getTriple().isAArch64();
if (isAArch64)
- isTrivialForABI = RD->canPassInRegisters() && isCXX14Aggregate(RD);
+ isTrivialForABI = RD->canPassInRegisters() && isTrivialForAArch64MSVC(RD);
// MSVC always returns structs indirectly from C++ instance methods.
bool isIndirectReturn = !isTrivialForABI || FI.isInstanceMethod();
@@ -4358,3 +4361,12 @@ MicrosoftCXXABI::LoadVTablePtr(CodeGenFunction &CGF, Address This,
performBaseAdjustment(CGF, This, QualType(RD->getTypeForDecl(), 0));
return {CGF.GetVTablePtr(This, CGM.Int8PtrTy, RD), RD};
}
+
+bool MicrosoftCXXABI::isPermittedToBeHomogeneousAggregate(
+ const CXXRecordDecl *CXXRD) const {
+ // MSVC Windows on Arm64 considers a type not HFA if it is not an
+ // aggregate according to the C++14 spec. This is not consistent with the
+ // AAPCS64, but is defacto spec on that platform.
+ return !CGM.getTarget().getTriple().isAArch64() ||
+ isTrivialForAArch64MSVC(CXXRD);
+}
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index d36c7344e284..9a11a0720f3c 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -5065,8 +5065,12 @@ bool ABIInfo::isHomogeneousAggregate(QualType Ty, const Type *&Base,
Members = 0;
- // If this is a C++ record, check the bases first.
+ // If this is a C++ record, check the properties of the record such as
+ // bases and ABI specific restrictions
if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
+ if (!getCXXABI().isPermittedToBeHomogeneousAggregate(CXXRD))
+ return false;
+
for (const auto &I : CXXRD->bases()) {
// Ignore empty records.
if (isEmptyRecord(getContext(), I.getType(), true))
diff --git a/clang/test/CodeGenCXX/homogeneous-aggregates.cpp b/clang/test/CodeGenCXX/homogeneous-aggregates.cpp
index 2b3af4226407..0fa30b2663bf 100644
--- a/clang/test/CodeGenCXX/homogeneous-aggregates.cpp
+++ b/clang/test/CodeGenCXX/homogeneous-aggregates.cpp
@@ -2,6 +2,7 @@
// RUN: %clang_cc1 -mfloat-abi hard -triple armv7-unknown-linux-gnueabi -emit-llvm -o - %s | FileCheck %s --check-prefix=ARM32
// RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=ARM64
// RUN: %clang_cc1 -mfloat-abi hard -triple x86_64-unknown-windows-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=X64
+// RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-windows-msvc -emit-llvm -o - %s | FileCheck %s --check-prefix=WOA64
#if defined(__x86_64__)
#define CC __attribute__((vectorcall))
@@ -104,3 +105,71 @@ struct HVAWithEmptyBitField : Float1, Float2 {
// ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z19with_empty_bitfield20HVAWithEmptyBitField(%struct.HVAWithEmptyBitField %a.coerce)
// X64: define dso_local x86_vectorcallcc void @"\01_Z19with_empty_bitfield20HVAWithEmptyBitField@@16"(%struct.HVAWithEmptyBitField inreg %a.coerce)
void CC with_empty_bitfield(HVAWithEmptyBitField a) {}
+
+namespace pr47611 {
+// MSVC on Arm includes "isCXX14Aggregate" as part of its definition of
+// Homogeneous Floating-point Aggregate (HFA). Additionally, it has a
diff erent
+// handling of C++14 aggregates, which can lead to confusion.
+
+// Pod is a trivial HFA.
+struct Pod {
+ double b[2];
+};
+// Not an aggregate according to C++14 spec => not HFA according to MSVC.
+struct NotCXX14Aggregate {
+ NotCXX14Aggregate();
+ Pod p;
+};
+// NotPod is a C++14 aggregate. But not HFA, because it contains
+// NotCXX14Aggregate (which itself is not HFA because it's not a C++14
+// aggregate).
+struct NotPod {
+ NotCXX14Aggregate x;
+};
+struct Empty {};
+// A class with a base is returned using the sret calling convetion by MSVC.
+struct HasEmptyBase : public Empty {
+ double b[2];
+};
+struct HasPodBase : public Pod {};
+// WOA64-LABEL: define dso_local %"struct.pr47611::Pod" @"?copy at pr47611@@YA?AUPod at 1@PEAU21@@Z"(%"struct.pr47611::Pod"* %x)
+Pod copy(Pod *x) { return *x; } // MSVC: ldp d0,d1,[x0], Clang: ldp d0,d1,[x0]
+// WOA64-LABEL: define dso_local void @"?copy at pr47611@@YA?AUNotCXX14Aggregate at 1@PEAU21@@Z"(%"struct.pr47611::NotCXX14Aggregate"* inreg noalias sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %agg.result, %"struct.pr47611::NotCXX14Aggregate"* %x)
+NotCXX14Aggregate copy(NotCXX14Aggregate *x) { return *x; } // MSVC: stp x8,x9,[x0], Clang: str q0,[x0]
+// WOA64-LABEL: define dso_local [2 x i64] @"?copy at pr47611@@YA?AUNotPod at 1@PEAU21@@Z"(%"struct.pr47611::NotPod"* %x)
+NotPod copy(NotPod *x) { return *x; }
+// WOA64-LABEL: define dso_local void @"?copy at pr47611@@YA?AUHasEmptyBase at 1@PEAU21@@Z"(%"struct.pr47611::HasEmptyBase"* inreg noalias sret(%"struct.pr47611::HasEmptyBase") align 8 %agg.result, %"struct.pr47611::HasEmptyBase"* %x)
+HasEmptyBase copy(HasEmptyBase *x) { return *x; }
+// WOA64-LABEL: define dso_local void @"?copy at pr47611@@YA?AUHasPodBase at 1@PEAU21@@Z"(%"struct.pr47611::HasPodBase"* inreg noalias sret(%"struct.pr47611::HasPodBase") align 8 %agg.result, %"struct.pr47611::HasPodBase"* %x)
+HasPodBase copy(HasPodBase *x) { return *x; }
+
+void call_copy_pod(Pod *pod) {
+ *pod = copy(pod);
+ // WOA64-LABEL: define dso_local void @"?call_copy_pod at pr47611@@YAXPEAUPod at 1@@Z"
+ // WOA64: %{{.*}} = call %"struct.pr47611::Pod" @"?copy at pr47611@@YA?AUPod at 1@PEAU21@@Z"(%"struct.pr47611::Pod"* %{{.*}})
+}
+
+void call_copy_notcxx14aggregate(NotCXX14Aggregate *notcxx14aggregate) {
+ *notcxx14aggregate = copy(notcxx14aggregate);
+ // WOA64-LABEL: define dso_local void @"?call_copy_notcxx14aggregate at pr47611@@YAXPEAUNotCXX14Aggregate at 1@@Z"
+ // WOA64: call void @"?copy at pr47611@@YA?AUNotCXX14Aggregate at 1@PEAU21@@Z"(%"struct.pr47611::NotCXX14Aggregate"* inreg sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %{{.*}}, %"struct.pr47611::NotCXX14Aggregate"* %{{.*}})
+}
+
+void call_copy_notpod(NotPod *notPod) {
+ *notPod = copy(notPod);
+ // WOA64-LABEL: define dso_local void @"?call_copy_notpod at pr47611@@YAXPEAUNotPod at 1@@Z"
+ // WOA64: %{{.*}} = call [2 x i64] @"?copy at pr47611@@YA?AUNotPod at 1@PEAU21@@Z"(%"struct.pr47611::NotPod"* %{{.*}})
+}
+
+void call_copy_hasemptybase(HasEmptyBase *hasEmptyBase) {
+ *hasEmptyBase = copy(hasEmptyBase);
+ // WOA64-LABEL: define dso_local void @"?call_copy_hasemptybase at pr47611@@YAXPEAUHasEmptyBase at 1@@Z"
+ // WOA64: call void @"?copy at pr47611@@YA?AUHasEmptyBase at 1@PEAU21@@Z"(%"struct.pr47611::HasEmptyBase"* inreg sret(%"struct.pr47611::HasEmptyBase") align 8 %{{.*}}, %"struct.pr47611::HasEmptyBase"* %{{.*}})
+}
+
+void call_copy_haspodbase(HasPodBase *hasPodBase) {
+ *hasPodBase = copy(hasPodBase);
+ // WOA64-LABEL: define dso_local void @"?call_copy_haspodbase at pr47611@@YAXPEAUHasPodBase at 1@@Z"
+ // WOA64: call void @"?copy at pr47611@@YA?AUHasPodBase at 1@PEAU21@@Z"(%"struct.pr47611::HasPodBase"* inreg sret(%"struct.pr47611::HasPodBase") align 8 %{{.*}}, %"struct.pr47611::HasPodBase"* %{{.*}})
+}
+}; // namespace pr47611
diff --git a/llvm/test/CodeGen/AArch64/arm64-windows-calls.ll b/llvm/test/CodeGen/AArch64/arm64-windows-calls.ll
index 1fee2246b751..47aefd358914 100644
--- a/llvm/test/CodeGen/AArch64/arm64-windows-calls.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-windows-calls.ll
@@ -98,3 +98,80 @@ entry:
%this1 = load %class.C*, %class.C** %this.addr, align 8
ret void
}
+
+; The following tests correspond to tests in
+; clang/test/CodeGenCXX/microsoft-abi-sret-and-byval.cpp
+
+; Pod is a trivial HFA
+%struct.Pod = type { [2 x double] }
+; Not an aggregate according to C++14 spec => not HFA according to MSVC
+%struct.NotCXX14Aggregate = type { %struct.Pod }
+; NotPod is a C++14 aggregate. But not HFA, because it contains
+; NotCXX14Aggregate (which itself is not HFA because it's not a C++14
+; aggregate).
+%struct.NotPod = type { %struct.NotCXX14Aggregate }
+
+; CHECK-LABEL: copy_pod:
+define dso_local %struct.Pod @copy_pod(%struct.Pod* %x) {
+ %x1 = load %struct.Pod, %struct.Pod* %x, align 8
+ ret %struct.Pod %x1
+ ; CHECK: ldp d0, d1, [x0]
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)
+
+; CHECK-LABEL: copy_notcxx14aggregate:
+define dso_local void
+ at copy_notcxx14aggregate(%struct.NotCXX14Aggregate* inreg noalias sret(%struct.NotCXX14Aggregate) align 8 %agg.result,
+ %struct.NotCXX14Aggregate* %x) {
+ %1 = bitcast %struct.NotCXX14Aggregate* %agg.result to i8*
+ %2 = bitcast %struct.NotCXX14Aggregate* %x to i8*
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 8 %1, i8* align 8 %2, i64 16, i1 false)
+ ret void
+ ; CHECK: str q0, [x0]
+}
+
+; CHECK-LABEL: copy_notpod:
+define dso_local [2 x i64] @copy_notpod(%struct.NotPod* %x) {
+ %x1 = bitcast %struct.NotPod* %x to [2 x i64]*
+ %x2 = load [2 x i64], [2 x i64]* %x1
+ ret [2 x i64] %x2
+ ; CHECK: ldp x8, x1, [x0]
+ ; CHECK: mov x0, x8
+}
+
+ at Pod = external global %struct.Pod
+
+; CHECK-LABEL: call_copy_pod:
+define void @call_copy_pod() {
+ %x = call %struct.Pod @copy_pod(%struct.Pod* @Pod)
+ store %struct.Pod %x, %struct.Pod* @Pod
+ ret void
+ ; CHECK: bl copy_pod
+ ; CHECK-NEXT: stp d0, d1, [{{.*}}]
+}
+
+ at NotCXX14Aggregate = external global %struct.NotCXX14Aggregate
+
+; CHECK-LABEL: call_copy_notcxx14aggregate:
+define void @call_copy_notcxx14aggregate() {
+ %x = alloca %struct.NotCXX14Aggregate
+ call void @copy_notcxx14aggregate(%struct.NotCXX14Aggregate* %x, %struct.NotCXX14Aggregate* @NotCXX14Aggregate)
+ %x1 = load %struct.NotCXX14Aggregate, %struct.NotCXX14Aggregate* %x
+ store %struct.NotCXX14Aggregate %x1, %struct.NotCXX14Aggregate* @NotCXX14Aggregate
+ ret void
+ ; CHECK: bl copy_notcxx14aggregate
+ ; CHECK-NEXT: ldp {{.*}}, {{.*}}, [sp]
+}
+
+ at NotPod = external global %struct.NotPod
+
+; CHECK-LABEL: call_copy_notpod:
+define void @call_copy_notpod() {
+ %x = call [2 x i64] @copy_notpod(%struct.NotPod* @NotPod)
+ %notpod = bitcast %struct.NotPod* @NotPod to [2 x i64]*
+ store [2 x i64] %x, [2 x i64]* %notpod
+ ret void
+ ; CHECK: bl copy_notpod
+ ; CHECK-NEXT: stp x0, x1, [{{.*}}]
+}
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