[clang] [Clang][Cygwin] Cygwin x86_64 should accepts __stdcall (PR #158385)
Tomohiro Kashiwada via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 12 16:50:06 PDT 2025
https://github.com/kikairoya created https://github.com/llvm/llvm-project/pull/158385
Cygwin should support calling convention attributes `__cdecl`, `__stdcall`, `__thiscall`, `__fastcall`, and `__vectorcall`, even though they have no effect in x86_64 except `__vectorcall`, as done in MinGW.
Originally reported in https://cygwin.com/pipermail/cygwin/2025-September/258782.html
>From c6dd0311d579abe0eca0f8f5e1ab9d2f8f9db18c Mon Sep 17 00:00:00 2001
From: kikairoya <kikairoya at gmail.com>
Date: Fri, 12 Sep 2025 21:56:19 +0900
Subject: [PATCH 1/2] set calling conv list
---
clang/lib/Basic/Targets/X86.h | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 6e013c95dbf01..d261540040e46 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -983,6 +983,7 @@ class LLVM_LIBRARY_VISIBILITY CygwinX86_64TargetInfo : public X86_64TargetInfo {
: X86_64TargetInfo(Triple, Opts) {
this->WCharType = TargetInfo::UnsignedShort;
this->WIntType = TargetInfo::UnsignedInt;
+ this->UseMicrosoftManglingForC = true;
}
void getTargetDefines(const LangOptions &Opts,
@@ -997,9 +998,37 @@ class LLVM_LIBRARY_VISIBILITY CygwinX86_64TargetInfo : public X86_64TargetInfo {
Builder.defineMacro("_GNU_SOURCE");
}
+ CallingConvCheckResult checkCallingConvention(CallingConv CC) const override {
+ switch (CC) {
+ case CC_X86StdCall:
+ case CC_X86ThisCall:
+ case CC_X86FastCall:
+ return CCCR_Ignore;
+ case CC_C:
+ case CC_X86VectorCall:
+ case CC_IntelOclBicc:
+ case CC_PreserveMost:
+ case CC_PreserveAll:
+ case CC_PreserveNone:
+ case CC_X86_64SysV:
+ case CC_Swift:
+ case CC_SwiftAsync:
+ case CC_X86RegCall:
+ case CC_DeviceKernel:
+ return CCCR_OK;
+ default:
+ return CCCR_Warning;
+ }
+ }
+
BuiltinVaListKind getBuiltinVaListKind() const override {
return TargetInfo::CharPtrBuiltinVaList;
}
+
+ TargetInfo::CallingConvKind
+ getCallingConvKind(bool ClangABICompat4) const override {
+ return CCK_MicrosoftWin64;
+ }
};
class LLVM_LIBRARY_VISIBILITY DarwinX86_64TargetInfo
>From 090635650aa436f93c540a6d580becbffb149097 Mon Sep 17 00:00:00 2001
From: kikairoya <kikairoya at gmail.com>
Date: Sat, 13 Sep 2025 08:19:42 +0900
Subject: [PATCH 2/2] stdcall test
---
clang/test/CodeGen/calling-conv-ignored.c | 2 ++
clang/test/CodeGen/ms_abi.c | 2 ++
clang/test/CodeGen/sysv_abi.c | 4 ++++
clang/test/DebugInfo/Generic/cc.c | 6 ++++--
clang/test/Parser/x64-windows-calling-convention-handling.c | 4 +++-
clang/test/Sema/MicrosoftCompatibility-x64.c | 4 +++-
6 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/clang/test/CodeGen/calling-conv-ignored.c b/clang/test/CodeGen/calling-conv-ignored.c
index 9c47f641eaacb..5dbc7e4084c88 100644
--- a/clang/test/CodeGen/calling-conv-ignored.c
+++ b/clang/test/CodeGen/calling-conv-ignored.c
@@ -1,5 +1,7 @@
// RUN: %clang_cc1 -triple i686-windows-msvc -emit-llvm -o - %s | FileCheck %s --check-prefix=X86
// RUN: %clang_cc1 -triple x86_64-windows-msvc -emit-llvm -o - %s | FileCheck %s --check-prefix=X64
+// RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=X64
+// RUN: %clang_cc1 -triple x86_64-cygwin -emit-llvm -o - %s | FileCheck %s --check-prefix=X64
// RUN: %clang_cc1 -triple i686-windows-msvc -emit-llvm -o - %s -fdefault-calling-conv=vectorcall | FileCheck %s --check-prefix=X86-VEC
// RUN: %clang_cc1 -triple x86_64-windows-msvc -emit-llvm -o - %s -fdefault-calling-conv=vectorcall | FileCheck %s --check-prefix=X64-VEC
diff --git a/clang/test/CodeGen/ms_abi.c b/clang/test/CodeGen/ms_abi.c
index 5d58c9816da78..2047febabdb11 100644
--- a/clang/test/CodeGen/ms_abi.c
+++ b/clang/test/CodeGen/ms_abi.c
@@ -1,5 +1,7 @@
// RUN: %clang_cc1 -triple x86_64-unknown-freebsd10.0 -emit-llvm < %s | FileCheck -check-prefix=FREEBSD %s
// RUN: %clang_cc1 -triple x86_64-pc-win32 -emit-llvm < %s | FileCheck -check-prefix=WIN64 %s
+// RUN: %clang_cc1 -triple x86_64-mingw -emit-llvm < %s | FileCheck -check-prefix=WIN64 %s
+// RUN: %clang_cc1 -triple x86_64-cygwin -emit-llvm < %s | FileCheck -check-prefix=WIN64 %s
// RUN: %clang_cc1 -triple x86_64-uefi -emit-llvm < %s | FileCheck -check-prefix=WIN64 %s
struct foo {
diff --git a/clang/test/CodeGen/sysv_abi.c b/clang/test/CodeGen/sysv_abi.c
index 29ea819c2aa26..a66ecc6e26242 100644
--- a/clang/test/CodeGen/sysv_abi.c
+++ b/clang/test/CodeGen/sysv_abi.c
@@ -1,7 +1,11 @@
// RUN: %clang_cc1 -triple x86_64-pc-win32 -emit-llvm -target-cpu skylake-avx512 < %s | FileCheck %s --check-prefixes=CHECK,AVX
+// RUN: %clang_cc1 -triple x86_64-mingw -emit-llvm -target-cpu skylake-avx512 < %s | FileCheck %s --check-prefixes=CHECK,AVX
+// RUN: %clang_cc1 -triple x86_64-cygwin -emit-llvm -target-cpu skylake-avx512 < %s | FileCheck %s --check-prefixes=CHECK,AVX
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -target-cpu skylake-avx512 < %s | FileCheck %s --check-prefixes=CHECK,AVX
// RUN: %clang_cc1 -triple x86_64-uefi -emit-llvm -target-cpu skylake-avx512 < %s | FileCheck %s --check-prefixes=CHECK,AVX
// RUN: %clang_cc1 -triple x86_64-pc-win32 -emit-llvm < %s | FileCheck %s --check-prefixes=CHECK,NOAVX
+// RUN: %clang_cc1 -triple x86_64-mingw -emit-llvm < %s | FileCheck %s --check-prefixes=CHECK,NOAVX
+// RUN: %clang_cc1 -triple x86_64-cygwin -emit-llvm < %s | FileCheck %s --check-prefixes=CHECK,NOAVX
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm < %s | FileCheck %s --check-prefixes=CHECK,NOAVX
// RUN: %clang_cc1 -triple x86_64-uefi -emit-llvm < %s | FileCheck %s --check-prefixes=CHECK,NOAVX
diff --git a/clang/test/DebugInfo/Generic/cc.c b/clang/test/DebugInfo/Generic/cc.c
index 2bfb1c28e9353..e430e4c8ed87b 100644
--- a/clang/test/DebugInfo/Generic/cc.c
+++ b/clang/test/DebugInfo/Generic/cc.c
@@ -1,5 +1,7 @@
// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=LINUX
-// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=WINDOWS
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=WINDOWS
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-gnu -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=WINDOWS
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-cygnus -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=WINDOWS
// RUN: %clang_cc1 -triple i386-pc-linux-gnu -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=LINUX32
// RUN: %clang_cc1 -triple armv7--linux-gnueabihf -o - -emit-llvm -debug-info-kind=limited %s | FileCheck %s --check-prefix=ARM
@@ -77,7 +79,7 @@ __attribute__((intel_ocl_bicc)) int add_inteloclbicc(int a, int b) {
}
#endif
-#ifdef _WIN64
+#if defined(_WIN64) || defined(__CYGWIN__)
// WINDOWS: !DISubprogram({{.*}}"add_sysvabi", {{.*}}type: ![[FTY:[0-9]+]]
// WINDOWS: ![[FTY]] = !DISubroutineType({{.*}}cc: DW_CC_LLVM_X86_64SysV,
__attribute__((sysv_abi)) int add_sysvabi(int a, int b) {
diff --git a/clang/test/Parser/x64-windows-calling-convention-handling.c b/clang/test/Parser/x64-windows-calling-convention-handling.c
index c027663414829..224931c4eb91d 100644
--- a/clang/test/Parser/x64-windows-calling-convention-handling.c
+++ b/clang/test/Parser/x64-windows-calling-convention-handling.c
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -triple x86_64-windows -fms-compatibility -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-windows -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-mingw -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64-cygwin -fsyntax-only -verify %s
int __cdecl cdecl(int a, int b, int c, int d) { // expected-no-diagnostics
return a + b + c + d;
diff --git a/clang/test/Sema/MicrosoftCompatibility-x64.c b/clang/test/Sema/MicrosoftCompatibility-x64.c
index 7d1f64996eb3c..a422b549dcc00 100644
--- a/clang/test/Sema/MicrosoftCompatibility-x64.c
+++ b/clang/test/Sema/MicrosoftCompatibility-x64.c
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 %s -Wmicrosoft -verify -fms-compatibility -triple x86_64-pc-win32
+// RUN: %clang_cc1 %s -Wmicrosoft -verify -triple x86_64-pc-win32
+// RUN: %clang_cc1 %s -Wmicrosoft -verify -triple x86_64-w64-mingw32
+// RUN: %clang_cc1 %s -Wmicrosoft -verify -triple x86_64-pc-cygwin
// None of these should warn. stdcall is treated as equivalent to cdecl on
// x64.
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