Author: Sudharsan Veeravalli Date: 2024-07-08T18:17:51-07:00 New Revision: d65f4232026a6c0fcd2431e1d28a7ad49127f6e5
URL: https://github.com/llvm/llvm-project/commit/d65f4232026a6c0fcd2431e1d28a7ad49127f6e5 DIFF: https://github.com/llvm/llvm-project/commit/d65f4232026a6c0fcd2431e1d28a7ad49127f6e5.diff LOG: [RISCV] Handle empty structs/unions passing in C++ (#97315) According to RISC-V integer calling convention empty structs or union arguments or return values are ignored by C compilers which support them as a non-standard extension. This is not the case for C++, which requires them to be sized types. Fixes #97285 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/CodeGen/Targets/RISCV.cpp clang/test/CodeGen/RISCV/abi-empty-structs.c Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 838cb69f647ee..e086b4fa43743 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -1084,6 +1084,7 @@ RISC-V Support - ``__attribute__((rvv_vector_bits(N)))`` is now supported for RVV vbool*_t types. - Profile names in ``-march`` option are now supported. +- Passing empty structs/unions as arguments in C++ is now handled correctly. The behavior is similar to GCC's. CUDA/HIP Language Changes ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/CodeGen/Targets/RISCV.cpp b/clang/lib/CodeGen/Targets/RISCV.cpp index a4c5ec315b8df..f2add9351c03c 100644 --- a/clang/lib/CodeGen/Targets/RISCV.cpp +++ b/clang/lib/CodeGen/Targets/RISCV.cpp @@ -361,12 +361,13 @@ ABIArgInfo RISCVABIInfo::classifyArgumentType(QualType Ty, bool IsFixed, CGCXXABI::RAA_DirectInMemory); } - // Ignore empty structs/unions. - if (isEmptyRecord(getContext(), Ty, true)) - return ABIArgInfo::getIgnore(); - uint64_t Size = getContext().getTypeSize(Ty); + // Ignore empty structs/unions whose size is zero. According to the calling + // convention empty structs/unions are required to be sized types in C++. + if (isEmptyRecord(getContext(), Ty, true) && Size == 0) + return ABIArgInfo::getIgnore(); + // Pass floating point values via FPRs if possible. if (IsFixed && Ty->isFloatingType() && !Ty->isComplexType() && FLen >= Size && ArgFPRsLeft) { diff --git a/clang/test/CodeGen/RISCV/abi-empty-structs.c b/clang/test/CodeGen/RISCV/abi-empty-structs.c index c48a2891627d4..5157165787fcb 100644 --- a/clang/test/CodeGen/RISCV/abi-empty-structs.c +++ b/clang/test/CodeGen/RISCV/abi-empty-structs.c @@ -167,6 +167,61 @@ struct s9 { // void test_s9(struct s9 a) {} +struct s10 { }; +// CHECK-C-LABEL: define dso_local void @test_s10 +// CHECK-C-SAME: () #[[ATTR0]] { +// CHECK-C: entry: +// +// CHECK32-CXX-LABEL: define dso_local i32 @_Z8test_s103s10 +// CHECK32-CXX-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] { +// CHECK32-CXX: entry: +// +// CHECK64-CXX-LABEL: define dso_local i64 @_Z8test_s103s10 +// CHECK64-CXX-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] { +// CHECK64-CXX: entry: +// +struct s10 test_s10(struct s10 a) { + return a; +} + +struct s11 { int : 0; }; +// CHECK-C-LABEL: define dso_local void @test_s11 +// CHECK-C-SAME: () #[[ATTR0]] { +// CHECK-C: entry: +// +// CHECK32-CXX-LABEL: define dso_local i32 @_Z8test_s113s11 +// CHECK32-CXX-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] { +// CHECK32-CXX: entry: +// +// CHECK64-CXX-LABEL: define dso_local i64 @_Z8test_s113s11 +// CHECK64-CXX-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] { +// CHECK64-CXX: entry: +// +struct s11 test_s11(struct s11 a) { + return a; +} + +struct s12 {int x[0];}; +// CHECK32-C-LABEL: define dso_local i32 @test_s12 +// CHECK32-C-SAME: (i32 noundef [[I1:%.*]], i32 noundef [[I2:%.*]]) #[[ATTR0]] { +// CHECK32-C: entry: +// +// CHECK64-C-LABEL: define dso_local signext i32 @test_s12 +// CHECK64-C-SAME: (i32 noundef signext [[I1:%.*]], i32 noundef signext [[I2:%.*]]) #[[ATTR0]] { +// CHECK64-C: entry: +// +// CHECK32-CXX-LABEL: define dso_local noundef i32 @_Z8test_s12i3s12i +// CHECK32-CXX-SAME: (i32 noundef [[I1:%.*]], i32 noundef [[I2:%.*]]) #[[ATTR0]] { +// CHECK32-CXX: entry: +// +// CHECK64-CXX-LABEL: define dso_local noundef signext i32 @_Z8test_s12i3s12i +// CHECK64-CXX-SAME: (i32 noundef signext [[I1:%.*]], i32 noundef signext [[I2:%.*]]) #[[ATTR0]] { +// CHECK64-CXX: entry: +// +int test_s12(int32_t i1, struct s12 a, int32_t i2) { + return i2; +} + //// NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line: // CHECK32-C: {{.*}} // CHECK64-C: {{.*}} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
