[Clang][Cygwin] Use correct BuiltinVaListKind.

[jeremyd2019]

This was in older patches for Cygwin support, but was somehow lost in the latest rounds.

[llvmbot]

@llvm/pr-subscribers-clang

Author: None (jeremyd2019)

Changes

This was in older patches for Cygwin support, but was somehow lost in the latest rounds.

---

Full diff: https://github.com/llvm/llvm-project/pull/143166.diff

1 Files Affected:

• (modified) clang/lib/Basic/Targets/X86.h (+4)

diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 3d58be8f898c6..b3fe98c5c742f 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -984,6 +984,10 @@ class LLVM_LIBRARY_VISIBILITY CygwinX86_64TargetInfo : public X86_64TargetInfo {
     this->WCharType = TargetInfo::UnsignedShort;
   }
 
+  BuiltinVaListKind getBuiltinVaListKind() const override {
+    return TargetInfo::CharPtrBuiltinVaList;
+  }
+
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override {
     X86_64TargetInfo::getTargetDefines(Opts, Builder);

[jeremyd2019]

@mstorsjo

[mstorsjo]

The change looks good, but can we have a test for it in some form?

[jeremyd2019]

I don't know - it's easy enough to do in vivo

#include <stdio.h>
#include <stdarg.h>

void test(const char * fmt, ...)
{
        va_list args;
        va_start(args, fmt);
        vprintf(fmt, args);
        va_end(args);
}

int main(void)
{
        test("asdf %d %s\n", 1, 1==1 ? "TEST" : "TESTS");
        return 0;
}

Before this change

asdf -13288 (null)

After

asdf 1 TEST

[jeremyd2019]

I'm not seeing an obvious place for a target-specific va_list test, can you suggest where this would go?

[mstorsjo]

I'm not seeing an obvious place for a target-specific va_list test, can you suggest where this would go?

No idea offhand; I tried breaking the existing getBuiltinVaListKind for WindowsX86_64TargetInfo and running check-clang, which caused failures in the following tests:

  Clang :: AST/ast-dump-template-json-win32-mangler-crash.cpp
  Clang :: CodeGen/ms_abi.c
  Clang :: CodeGenCXX/ext-int.cpp

So some of them may contain a good sample for tests that cover this bit.

[jeremyd2019]

None of those really cry out to me as a place to extend with a cygwin test... but adding a new test in CodeGen that validates that the va_list works the same on windows and cygwin based on the existing tests wouldn't be too hard.

[kikairoya]

I have a test already: #143115