[clang] Fix interaction between asm labels and inline builtins

[serge-sans-paille]

Summary

One must pick the same name as the one referenced in CodeGenFunction when
generating .inline version of an inline builtin, otherwise they are not
correctly replaced.

[serge-sans-paille]

(rebased on main branch)

[aaron.ballman]

Adding some more codegen reviewers. Can you add a release note for the fix?

[nickdesaulniers]

clang/test/CodeGen/asm-label-inline-builtins.c

19–21

please be consistent wrt. the trailing open paren (.

Let's add a check for the declaration of @vprintf.inline?

[nickdesaulniers]

clang/lib/CodeGen/CGExpr.cpp

5056–5057

I think you could use:

if (auto *A = FD->getAttr<AsmLabelAttr>())
  FDInlineName = A->getLabel().str();
else
  ...

[efriedma]

clang/lib/CodeGen/CGExpr.cpp

5057

This is throwing away the ".inline" suffix? Is that intentional?

[serge-sans-paille]

Address reviews.

[nickdesaulniers]

Please make sure to mark comments as "Done" in phab to help reviewers skip over stale feedback.

clang/lib/CodeGen/CGExpr.cpp

5055–5059

Might be able to DRY this up slightly more:

auto *A = FD->getAttr<AsmLabelAttr>();
StringRef Ident = A ? A->getLabel() : FD->getName();
std::string FDInlineName = (Ident + ".inline").str();

clang/docs/ReleaseNotes.rst

- Respect constructor constraints during class template argument deduction (CTAD).
   This is the suggested resolution to CWG DR2628.
   `Issue 57646 <https://github.com/llvm/llvm-project/issues/57646>`_
   `Issue 43829 <https://github.com/llvm/llvm-project/issues/43829>`_
 - Fixed a crash in C++20 mode in Clang and Clangd when compile source
   with compilation errors.
   `Issue 53628 <https://github.com/llvm/llvm-project/issues/53628>`_
 - The template arguments of a variable template being accessed as a
   member will now be represented in the AST.
+- Fix incorrect handling of inline builtins with asm labels.
 
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 - Clang will now check compile-time determinable string literals as format strings.
   Fixes `Issue 55805: <https://github.com/llvm/llvm-project/issues/55805>`_.
 - ``-Wformat`` now recognizes ``%b`` for the ``printf``/``scanf`` family of
   functions and ``%B`` for the ``printf`` family of functions. Fixes

clang/lib/CodeGen/CGExpr.cpp

 }
 
 static CGCallee EmitDirectCallee(CodeGenFunction &CGF, GlobalDecl GD) {
   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
 
   if (auto builtinID = FD->getBuiltinID()) {
     std::string NoBuiltinFD = ("no-builtin-" + FD->getName()).str();
     std::string NoBuiltins = "no-builtins";
-    std::string FDInlineName = (FD->getName() + ".inline").str();
+
+    auto *A = FD->getAttr<AsmLabelAttr>();
+    StringRef Ident = A ? A->getLabel() : FD->getName();
+    std::string FDInlineName = (Ident + ".inline").str();
 
     bool IsPredefinedLibFunction =
         CGF.getContext().BuiltinInfo.isPredefinedLibFunction(builtinID);
     bool HasAttributeNoBuiltin =
         CGF.CurFn->getAttributes().hasFnAttr(NoBuiltinFD) ||
         CGF.CurFn->getAttributes().hasFnAttr(NoBuiltins);
 
     // When directing calling an inline builtin, call it through it's mangled
     // name to make it clear it's not the actual builtin.
     if (CGF.CurFn->getName() != FDInlineName &&

clang/test/CodeGen/asm-label-inline-builtins.c

+// RUN: %clang_cc1 -triple x86_64 -S -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+//
+// Verifies that clang-generated *.inline carry the same name at call and callee
+// site, in spite of asm labels.
+
+typedef struct _IO_FILE FILE;
+extern FILE *stdout;
+extern int vprintf (const char *__restrict __format, __builtin_va_list __arg);
+extern int __vfprintf_chk (FILE *__restrict __stream, int __flag,
+      const char *__restrict __format, __builtin_va_list __ap);
+extern int __vprintf_chk (int __flag, const char *__restrict __format,
+     __builtin_va_list __ap);
+
+extern __typeof (vprintf) vprintf __asm ("__vprintfieee128");
+extern __typeof (__vfprintf_chk) __vfprintf_chk __asm ("__vfprintf_chkieee128");
+extern __typeof (__vprintf_chk) __vprintf_chk __asm ("__vprintf_chkieee128");
+
+extern __inline __attribute__ ((__always_inline__)) __attribute__ ((__gnu_inline__)) __attribute__ ((__artificial__)) int
+vprintf (const char *__restrict __fmt, __builtin_va_list __ap)
+{
+  return __vfprintf_chk (stdout, 2 - 1, __fmt, __ap);
+}
+
+void test(const char *fmt, __builtin_va_list ap) {
+  vprintf(fmt, ap);
+}
+
+// CHECK-LABEL: void @test(
+// CHECK: call i32 @__vprintfieee128.inline(
+//
+// CHECK-LABEL: internal i32 @__vprintfieee128.inline(
+// CHECK: call i32 @__vfprintf_chkieee128(