SixWeining updated this revision to Diff 547711.
SixWeining added a comment.
add an extra check for when a candidate from detectFAREligibleStructHelper may
not be valid
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D156116/new/
https://reviews.llvm.org/D156116
Files:
clang/docs/ReleaseNotes.rst
clang/lib/CodeGen/Targets/LoongArch.cpp
clang/test/CodeGen/LoongArch/abi-lp64d-empty-structs.c
Index: clang/test/CodeGen/LoongArch/abi-lp64d-empty-structs.c
===================================================================
--- clang/test/CodeGen/LoongArch/abi-lp64d-empty-structs.c
+++ clang/test/CodeGen/LoongArch/abi-lp64d-empty-structs.c
@@ -3,7 +3,6 @@
// RUN: %clang_cc1 -triple loongarch64 -target-feature +f -target-feature +d -target-abi lp64d -emit-llvm %s -o - -x c++ | \
// RUN: FileCheck --check-prefix=CHECK-CXX %s
-// FIXME: This isn't currently respected.
// Fields containing empty structs or unions are ignored when flattening
// structs to examine whether the structs can be passed via FARs, even in C++.
// But there is an exception that non-zero-length array of empty structures are
@@ -16,7 +15,7 @@
struct s1 { struct empty e; float f; };
// CHECK-C: define{{.*}} float @test_s1(float {{.*}})
-// CHECK-CXX: define{{.*}} i64 @_Z7test_s12s1(i64 {{.*}})
+// CHECK-CXX: define{{.*}} float @_Z7test_s12s1(float {{.*}})
struct s1 test_s1(struct s1 a) {
return a;
}
@@ -24,7 +23,7 @@
struct s2 { struct empty e; int32_t i; float f; };
// CHECK-C: define{{.*}} { i32, float } @test_s2(i32 {{.*}}, float {{.*}})
-// CHECK-CXX: define{{.*}} [2 x i64] @_Z7test_s22s2([2 x i64] {{.*}})
+// CHECK-CXX: define{{.*}} { i32, float } @_Z7test_s22s2(i32 {{.*}}, float {{.*}})
struct s2 test_s2(struct s2 a) {
return a;
}
@@ -32,7 +31,7 @@
struct s3 { struct empty e; float f; float g; };
// CHECK-C: define{{.*}} { float, float } @test_s3(float {{.*}}, float {{.*}})
-// CHECK-CXX: define{{.*}} [2 x i64] @_Z7test_s32s3([2 x i64] {{.*}})
+// CHECK-CXX: define{{.*}} { float, float } @_Z7test_s32s3(float {{.*}}, float {{.*}})
struct s3 test_s3(struct s3 a) {
return a;
}
@@ -40,7 +39,7 @@
struct s4 { struct empty e; float __complex__ c; };
// CHECK-C: define{{.*}} { float, float } @test_s4(float {{.*}}, float {{.*}})
-// CHECK-CXX: define{{.*}} [2 x i64] @_Z7test_s42s4([2 x i64] {{.*}})
+// CHECK-CXX: define{{.*}} { float, float } @_Z7test_s42s4(float {{.*}}, float {{.*}})
struct s4 test_s4(struct s4 a) {
return a;
}
@@ -77,7 +76,14 @@
struct s8 { struct empty_arr0 e; float f; };
// CHECK-C: define{{.*}} float @test_s8(float {{.*}})
-// CHECK-CXX: define{{.*}} i64 @_Z7test_s82s8(i64 {{.*}})
+// CHECK-CXX: define{{.*}} float @_Z7test_s82s8(float {{.*}})
struct s8 test_s8(struct s8 a) {
return a;
}
+
+// CHECK-C: define{{.*}} void @test_s9()
+// CHECK-CXX: define{{.*}} i64 @_Z7test_s92s9(i64 {{.*}})
+struct s9 { struct empty e; };
+struct s9 test_s9(struct s9 a) {
+ return a;
+}
Index: clang/lib/CodeGen/Targets/LoongArch.cpp
===================================================================
--- clang/lib/CodeGen/Targets/LoongArch.cpp
+++ clang/lib/CodeGen/Targets/LoongArch.cpp
@@ -148,6 +148,13 @@
if (const ConstantArrayType *ATy = getContext().getAsConstantArrayType(Ty)) {
uint64_t ArraySize = ATy->getSize().getZExtValue();
QualType EltTy = ATy->getElementType();
+ // Non-zero-length arrays of empty records make the struct ineligible to be
+ // passed via FARs in C++.
+ if (const auto *RTy = EltTy->getAs<RecordType>()) {
+ if (ArraySize != 0 && isa<CXXRecordDecl>(RTy->getDecl()) &&
+ isEmptyRecord(getContext(), EltTy, true, true))
+ return false;
+ }
CharUnits EltSize = getContext().getTypeSizeInChars(EltTy);
for (uint64_t i = 0; i < ArraySize; ++i) {
if (!detectFARsEligibleStructHelper(EltTy, CurOff, Field1Ty, Field1Off,
@@ -163,7 +170,7 @@
// copy constructor are not eligible for the FP calling convention.
if (getRecordArgABI(Ty, CGT.getCXXABI()))
return false;
- if (isEmptyRecord(getContext(), Ty, true))
+ if (isEmptyRecord(getContext(), Ty, true, true))
return true;
const RecordDecl *RD = RTy->getDecl();
// Unions aren't eligible unless they're empty (which is caught above).
@@ -222,6 +229,8 @@
if (!detectFARsEligibleStructHelper(Ty, CharUnits::Zero(), Field1Ty,
Field1Off, Field2Ty, Field2Off))
return false;
+ if (!Field1Ty)
+ return false;
// Not really a candidate if we have a single int but no float.
if (Field1Ty && !Field2Ty && !Field1Ty->isFloatingPointTy())
return false;
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -192,6 +192,9 @@
LoongArch Support
^^^^^^^^^^^^^^^^^
+- An ABI mismatch between GCC and Clang related to the handling of empty structs
+ in C++ parameter passing under ``lp64d`` ABI was fixed.
+
RISC-V Support
^^^^^^^^^^^^^^
- Unaligned memory accesses can be toggled by ``-m[no-]unaligned-access`` or the
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