[clang] Turn -fno-builtin flag into an IR Attribute

Summary:
This is a follow up on https://reviews.llvm.org/D61634#1742154 to turn the clang driver -fno-builtin flag into an IR attribute.
I also investigated pushing the attribute earlier on (in Sema) but it looks like this patch is simple and will cover all function calls.

Reviewers: aaron.ballman, courbet

Subscribers: cfe-commits, tejohnson

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71193

1 files changed, 14 insertions, 11 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index d41516b..b49b194 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1877,17 +1877,20 @@ void CodeGenModule::ConstructAttributeList(
         if (Fn->isNoReturn())
           FuncAttrs.addAttribute(llvm::Attribute::NoReturn);
 
-        if (const auto *NBA = TargetDecl->getAttr<NoBuiltinAttr>()) {
-          bool HasWildcard = llvm::is_contained(NBA->builtinNames(), "*");
-          if (HasWildcard)
-            FuncAttrs.addAttribute("no-builtins");
-          else
-            for (StringRef BuiltinName : NBA->builtinNames()) {
-              SmallString<32> AttributeName;
-              AttributeName += "no-builtin-";
-              AttributeName += BuiltinName;
-              FuncAttrs.addAttribute(AttributeName);
-            }
+        const auto *NBA = Fn->getAttr<NoBuiltinAttr>();
+        bool HasWildcard = NBA && llvm::is_contained(NBA->builtinNames(), "*");
+        if (getLangOpts().NoBuiltin || HasWildcard)
+          FuncAttrs.addAttribute("no-builtins");
+        else {
+          auto AddNoBuiltinAttr = [&FuncAttrs](StringRef BuiltinName) {
+            SmallString<32> AttributeName;
+            AttributeName += "no-builtin-";
+            AttributeName += BuiltinName;
+            FuncAttrs.addAttribute(AttributeName);
+          };
+          llvm::for_each(getLangOpts().NoBuiltinFuncs, AddNoBuiltinAttr);
+          if (NBA)
+            llvm::for_each(NBA->builtinNames(), AddNoBuiltinAttr);
         }
       }
     }