Author: quantum Date: Tue Aug 13 14:41:11 2019 New Revision: 368750 URL: http://llvm.org/viewvc/llvm-project?rev=368750&view=rev Log: [WebAssembly] Make clang emit correct va_arg code for structs
Summary: In the WebAssembly backend, when lowering variadic function calls, non-single member aggregate type arguments are always passed by pointer. However, when emitting va_arg code in clang, the arguments are instead read as if they are passed directly. This results in the pointer being read as the actual structure. Fixes https://github.com/emscripten-core/emscripten/issues/9042. Reviewers: tlively, sbc100, kripken, aheejin, dschuff Reviewed By: dschuff Subscribers: dschuff, jgravelle-google, sunfish, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D66168 Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp cfe/trunk/test/CodeGen/wasm-varargs.c Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=368750&r1=368749&r2=368750&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original) +++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Tue Aug 13 14:41:11 2019 @@ -833,10 +833,12 @@ ABIArgInfo WebAssemblyABIInfo::classifyR Address WebAssemblyABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr, QualType Ty) const { - return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*IsIndirect=*/ false, + bool IsIndirect = + isAggregateTypeForABI(Ty) && !isSingleElementStruct(Ty, getContext()); + return emitVoidPtrVAArg(CGF, VAListAddr, Ty, IsIndirect, getContext().getTypeInfoInChars(Ty), CharUnits::fromQuantity(4), - /*AllowHigherAlign=*/ true); + /*AllowHigherAlign=*/true); } //===----------------------------------------------------------------------===// Modified: cfe/trunk/test/CodeGen/wasm-varargs.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/wasm-varargs.c?rev=368750&r1=368749&r2=368750&view=diff ============================================================================== --- cfe/trunk/test/CodeGen/wasm-varargs.c (original) +++ cfe/trunk/test/CodeGen/wasm-varargs.c Tue Aug 13 14:41:11 2019 @@ -87,12 +87,13 @@ struct S test_struct(char *fmt, ...) { // CHECK: [[VA1:%[^,=]+]] = bitcast i8** [[VA]] to i8* // CHECK: call void @llvm.va_start(i8* [[VA1]]) // CHECK: [[ARGP_CUR:%[^,=]+]] = load i8*, i8** [[VA]], align 4 -// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8* [[ARGP_CUR]], i32 12 +// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8* [[ARGP_CUR]], i32 4 // CHECK: store i8* [[ARGP_NEXT]], i8** [[VA]], align 4 -// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]* -// CHECK: [[R4:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8* -// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R3]] to i8* -// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R4]], i8* align 4 [[R5]], i32 12, i1 false) +// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]** +// CHECK: [[R4:%[^,=]+]] = load [[STRUCT_S]]*, [[STRUCT_S]]** %0, align 4 +// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8* +// CHECK: [[R6:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R4]] to i8* +// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R5]], i8* align 4 [[R6]], i32 12, i1 false) // CHECK: [[VA2:%[^,=]+]] = bitcast i8** [[VA]] to i8* // CHECK: call void @llvm.va_end(i8* [[VA2]]) // CHECK: ret void _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
