From 4b20b3c80c5561040f0c0e7358b88fe8f97cf3c6 Mon Sep 17 00:00:00 2001 From: Alexander Ivchenko Date: Thu, 8 Feb 2018 11:15:21 +0000 Subject: [PATCH] Fix for #31362 - ms_abi is implemented incorrectly for values >=16 bytes. Summary: This patch is a fix for following issue: https://bugs.llvm.org/show_bug.cgi?id=31362 The problem was caused by front end lowering C calling conventions without taking into account calling conventions enforced by attribute. In this case win64cc was no correctly lowered on targets other than Windows. Reviewed By: rnk (Reid Kleckner) Differential Revision: https://reviews.llvm.org/D43016 Author: belickim llvm-svn: 324594 --- clang/lib/CodeGen/TargetInfo.cpp | 12 +++++++++++- clang/test/CodeGen/ms_abi.c | 13 +++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp index f1f2451..4ca421b 100644 --- a/clang/lib/CodeGen/TargetInfo.cpp +++ b/clang/lib/CodeGen/TargetInfo.cpp @@ -3529,7 +3529,17 @@ ABIArgInfo X86_64ABIInfo::classifyRegCallStructType(QualType Ty, void X86_64ABIInfo::computeInfo(CGFunctionInfo &FI) const { - bool IsRegCall = FI.getCallingConvention() == llvm::CallingConv::X86_RegCall; + const unsigned CallingConv = FI.getCallingConvention(); + // It is possible to force Win64 calling convention on any x86_64 target by + // using __attribute__((ms_abi)). In such case to correctly emit Win64 + // compatible code delegate this call to WinX86_64ABIInfo::computeInfo. + if (CallingConv == llvm::CallingConv::Win64) { + WinX86_64ABIInfo Win64ABIInfo(CGT); + Win64ABIInfo.computeInfo(FI); + return; + } + + bool IsRegCall = CallingConv == llvm::CallingConv::X86_RegCall; // Keep track of the number of assigned registers. unsigned FreeIntRegs = IsRegCall ? 11 : 6; diff --git a/clang/test/CodeGen/ms_abi.c b/clang/test/CodeGen/ms_abi.c index 407087e..7486166 100644 --- a/clang/test/CodeGen/ms_abi.c +++ b/clang/test/CodeGen/ms_abi.c @@ -146,3 +146,16 @@ void __attribute__((sysv_abi)) f6(__builtin_ms_va_list ap) { // WIN64: %[[AP_VAL:.*]] = load i8*, i8** %[[AP]] // WIN64-NEXT: store i8* %[[AP_VAL]], i8** %[[AP2:.*]] } + +// This test checks if structs are passed according to Win64 calling convention +// when it's enforced by __attribute((ms_abi)). +struct i128 { + unsigned long long a; + unsigned long long b; +}; + +__attribute__((ms_abi)) struct i128 f7(struct i128 a) { + // WIN64: define void @f7(%struct.i128* noalias sret %agg.result, %struct.i128* %a) + // FREEBSD: define win64cc void @f7(%struct.i128* noalias sret %agg.result, %struct.i128* %a) + return a; +} -- 2.7.4