Author: Longsheng Mou Date: 2024-04-03T19:12:12+08:00 New Revision: 956b47b48616148c15f8f95d76d5e0c215fe095c
URL: https://github.com/llvm/llvm-project/commit/956b47b48616148c15f8f95d76d5e0c215fe095c DIFF: https://github.com/llvm/llvm-project/commit/956b47b48616148c15f8f95d76d5e0c215fe095c.diff LOG: [X86_32] Teach X86_32 va_arg to ignore empty structs. (#86075) Empty structs are ignored for parameter passing purposes, but va_arg was incrementing the pointer anyway for that the size of empty struct in c++ is 1 byte, which could lead to va_list getting out of sync. Fix #86057. Added: clang/test/CodeGenCXX/x86_32-vaarg.cpp Modified: clang/lib/CodeGen/Targets/X86.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/Targets/X86.cpp b/clang/lib/CodeGen/Targets/X86.cpp index 1146a851a7715d..c831777699f627 100644 --- a/clang/lib/CodeGen/Targets/X86.cpp +++ b/clang/lib/CodeGen/Targets/X86.cpp @@ -1069,6 +1069,12 @@ Address X86_32ABIInfo::EmitVAArg(CodeGenFunction &CGF, auto TypeInfo = getContext().getTypeInfoInChars(Ty); + CCState State(*const_cast<CGFunctionInfo *>(CGF.CurFnInfo)); + ABIArgInfo AI = classifyArgumentType(Ty, State, /*ArgIndex*/ 0); + // Empty records are ignored for parameter passing purposes. + if (AI.isIgnore()) + return CGF.CreateMemTemp(Ty); + // x86-32 changes the alignment of certain arguments on the stack. // // Just messing with TypeInfo like this works because we never pass diff --git a/clang/test/CodeGenCXX/x86_32-vaarg.cpp b/clang/test/CodeGenCXX/x86_32-vaarg.cpp new file mode 100644 index 00000000000000..dcc2f7f96a40f1 --- /dev/null +++ b/clang/test/CodeGenCXX/x86_32-vaarg.cpp @@ -0,0 +1,21 @@ +// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py +// RUN: %clang_cc1 -triple i386-linux-gnu -emit-llvm -o - %s | FileCheck %s + +typedef struct {} empty; + +// CHECK-LABEL: @_Z17empty_record_testiz( +// CHECK-NEXT: entry: +// CHECK-NEXT: [[RESULT_PTR:%.*]] = alloca ptr, align 4 +// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4 +// CHECK-NEXT: [[LIST:%.*]] = alloca ptr, align 4 +// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_EMPTY:%.*]], align 1 +// CHECK-NEXT: store ptr [[AGG_RESULT:%.*]], ptr [[RESULT_PTR]], align 4 +// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4 +// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[LIST]]) +// CHECK-NEXT: ret void +// +empty empty_record_test(int z, ...) { + __builtin_va_list list; + __builtin_va_start(list, z); + return __builtin_va_arg(list, empty); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
