[AArch64] Ignore stdcall and similar on aarch64/windows

[mstorsjo]

Summary

This is similar to what's done on arm and x86_64, where these calling conventions are silently ignored, as in SVN r245076 (D12034).

[rnk]

lib/Basic/Targets/AArch64.cpp

466–467 ↗

(On Diff #108977)

Do they really ignore fastcall and vectorcall on arm64?

I assume thiscall and stdcall are all over various Win SDK headers, so they need to be ignored for compatibility, but I've never seen public documented APIs using __vectorcall. The STL ifdefs out those overloads, right?

[mstorsjo]

lib/Basic/Targets/AArch64.cpp

466–467 ↗

(On Diff #108977)

I don't have MSVC for arm64 to test with (but @mgrang does so he can check), but I included them for consistency and completeness.

[mstorsjo]

lib/Basic/Targets/AArch64.cpp

466–467 ↗

(On Diff #108977)

@mgrang - can you check whether this compiles without warnings (with e.g. -W3) on MSVC?

void __stdcall foo(void) {
}

void __fastcall bar(void) {
}

void __vectorcall baz(void) {
}

@rnk - FWIW, I checked MSVC for ARM (32 bit), and that one also ignores all of them without a warning.

[mstorsjo]

Ping @mgrang, can you check the above with MSVC? I'd like to move forward with this in one form or another.

[mgrang]

In D36105#834007, @mstorsjo wrote:

Ping @mgrang, can you check the above with MSVC? I'd like to move forward with this in one form or another.

Yes, I checked with MSVC for ARM64 and it compiles without any warnings.

cl foo.c -c /W3
Microsoft (R) C/C++ Optimizing Compiler for ARM64
Copyright (C) Microsoft Corporation.  All rights reserved.

foo.c

[mstorsjo]

In D36105#834225, @mgrang wrote:

In D36105#834007, @mstorsjo wrote:

Ping @mgrang, can you check the above with MSVC? I'd like to move forward with this in one form or another.

Yes, I checked with MSVC for ARM64 and it compiles without any warnings.

Thanks! @rnk - is this ok then?

[rnk]

lgtm

cfe/trunk/lib/Basic/Targets/AArch64.h

public:
   void setDataLayout() override;
 
   void getVisualStudioDefines(const LangOptions &Opts,
                               MacroBuilder &Builder) const;
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override;
 
   BuiltinVaListKind getBuiltinVaListKind() const override;
+
+  CallingConvCheckResult checkCallingConvention(CallingConv CC) const override;
 };
 
 class LLVM_LIBRARY_VISIBILITY AArch64beTargetInfo : public AArch64TargetInfo {
 public:
   AArch64beTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts);
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override;
 

cfe/trunk/lib/Basic/Targets/AArch64.cpp

void MicrosoftARM64TargetInfo::getTargetDefines(const LangOptions &Opts,
   getVisualStudioDefines(Opts, Builder);
 }
 
 TargetInfo::BuiltinVaListKind
 MicrosoftARM64TargetInfo::getBuiltinVaListKind() const {
   return TargetInfo::CharPtrBuiltinVaList;
 }
 
+TargetInfo::CallingConvCheckResult
+MicrosoftARM64TargetInfo::checkCallingConvention(CallingConv CC) const {
+  switch (CC) {
+  case CC_X86StdCall:
+  case CC_X86ThisCall:
+  case CC_X86FastCall:
+  case CC_X86VectorCall:
+    return CCCR_Ignore;
+  case CC_C:
+  case CC_OpenCLKernel:
+  case CC_Win64:
+    return CCCR_OK;
+  default:
+    return CCCR_Warning;
+  }
+}
+
 DarwinAArch64TargetInfo::DarwinAArch64TargetInfo(const llvm::Triple &Triple,
                                                  const TargetOptions &Opts)
     : DarwinTargetInfo<AArch64leTargetInfo>(Triple, Opts) {
   Int64Type = SignedLongLong;
   WCharType = SignedInt;
   UseSignedCharForObjCBool = false;
 
   LongDoubleWidth = LongDoubleAlign = SuitableAlign = 64;

cfe/trunk/test/Parser/arm-windows-calling-convention-handling.c

 // RUN: %clang_cc1 -triple thumbv7-windows -fms-compatibility -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple aarch64-windows -fms-compatibility -fsyntax-only -verify %s
 
 int __cdecl cdecl(int a, int b, int c, int d) { // expected-no-diagnostics
   return a + b + c + d;
 }
 
 float __stdcall stdcall(float a, float b, float c, float d) { // expected-no-diagnostics
   return a + b + c + d;
 }