[clang] [CIR] Upstream minimal builtin function call support (PR #142981)

[Erich Keane via cfe-commits]

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@@ -1004,8 +1004,48 @@ static cir::FuncOp emitFunctionDeclPointer(CIRGenModule &cgm, GlobalDecl gd) {
   return cgm.getAddrOfFunction(gd);
 }
 
-static CIRGenCallee emitDirectCallee(CIRGenModule &cgm, GlobalDecl gd) {
-  assert(!cir::MissingFeatures::opCallBuiltinFunc());
+// Detect the unusual situation where an inline version is shadowed by a
+// non-inline version. In that case we should pick the external one
+// everywhere. That's GCC behavior too.
+static bool onlyHasInlineBuiltinDeclaration(const FunctionDecl *fd) {
+  for (const FunctionDecl *pd = fd; pd; pd = pd->getPreviousDecl())
+    if (!pd->isInlineBuiltinDeclaration())
+      return false;
+  return true;
+}
+
+CIRGenCallee CIRGenFunction::emitDirectCallee(const GlobalDecl &gd) {
+  const auto *fd = cast<FunctionDecl>(gd.getDecl());
+
+  if (unsigned builtinID = fd->getBuiltinID()) {
+    std::string noBuiltinFD = ("no-builtin-" + fd->getName()).str();
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erichkeane wrote:

What is this for? And the line below?

https://github.com/llvm/llvm-project/pull/142981