[llvm-bugs] [Bug 37122] New: Lvalue reference types appear in the signature of __builtin_va_start when compiled as C and targeting Windows

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=37122

            Bug ID: 37122
           Summary: Lvalue reference types appear in the signature of
                    __builtin_va_start when compiled as C and targeting
                    Windows
           Product: clang
           Version: 6.0
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: thonerma at synopsys.com
                CC: llvm-bugs at lists.llvm.org

It seems that the signature of __builtin_va_start contains a C++ lvalue
reference type when targeting Windows, even when compiling as C:

$ cat t.c
void f(int n, ...) {
  __builtin_va_list v;
  __builtin_va_start(v, n);
}

$ clang --version
clang version 6.0.0 (tags/RELEASE_600/final)
Target: x86_64-unknown-linux-gnu
...

$ clang -c -Xclang -ast-dump -target x86_64-pc-windows-gnu t.c
...
`-FunctionDecl 0x4c89578 <col:3> col:3 implicit used __builtin_va_start 'void
(__builtin_va_list &, ...)' extern
  |-ParmVarDecl 0x4c89618 <<invalid sloc>> <invalid sloc> '__builtin_va_list &'
  `-NoThrowAttr 0x4c89680 <col:3> Implicit

Note the presence of '__builtin_va_list &' as a parameter type.

The lvalue reference is a surprise for AST consumers that do not expect to
encounter C++ reference types in code compiled as C.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20180413/ae9c0a26/attachment.html>