Fis for Assertion failure on dependent expression.

[Sunil_Srivastava]

Summary

The check for the value passed to __buildtin_return_address needs to be guarded by check for the Dependent context, or else it runs into an assertion failure in the test case given below.

[erichkeane]

Fix looks fine, I'm on the fence about how to handle the test, whether it is valuable to convert it to a C++ test and omit the #ifdef/extra run line, or leave it as it is (without the 2nd run with Wmost).

I'll leave the opinion here to other reviewers/submitter to deal with before commit.

clang/test/Sema/builtin-returnaddress.c

3

I don't think the -Wmost test 'RUN' line is valuable for the C++ mode, it is simply validating that this diagnostic is in Wmost mode (which running in C mode is sufficient).

[Sunil_Srivastava]

clang/test/Sema/builtin-returnaddress.c

3

Good point. I will remove that.

clang/lib/Sema/SemaChecking.cpp

#include "clang/Basic/Builtins.def"
   case Builtin::BI__builtin_frame_address:
   case Builtin::BI__builtin_return_address: {
     if (SemaBuiltinConstantArgRange(TheCall, 0, 0, 0xFFFF))
       return ExprError();
 
     // -Wframe-address warning if non-zero passed to builtin
     // return/frame address.
     Expr::EvalResult Result;
-    if (TheCall->getArg(0)->EvaluateAsInt(Result, getASTContext()) &&
+    if (!TheCall->getArg(0)->isValueDependent() &&
+        TheCall->getArg(0)->EvaluateAsInt(Result, getASTContext()) &&
         Result.Val.getInt() != 0)
       Diag(TheCall->getBeginLoc(), diag::warn_frame_address)
           << ((BuiltinID == Builtin::BI__builtin_return_address)
                   ? "__builtin_return_address"
                   : "__builtin_frame_address")
           << TheCall->getSourceRange();
     break;
   }

clang/test/Sema/builtin-returnaddress.c

 // RUN: %clang_cc1 -fsyntax-only -Wframe-address -verify %s
 // RUN: %clang_cc1 -fsyntax-only -Wmost -verify %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wframe-address -verify %s
 
 void* a(unsigned x) {
 return __builtin_return_address(0);
 }
 
 void* b(unsigned x) {
 return __builtin_return_address(1); // expected-warning{{calling '__builtin_return_address' with a nonzero argument is unsafe}}
 }
 
 void* c(unsigned x) {
 return __builtin_frame_address(0);
 }
 
 void* d(unsigned x) {
 return __builtin_frame_address(1); // expected-warning{{calling '__builtin_frame_address' with a nonzero argument is unsafe}}
 }
 
+#ifdef __cplusplus
+template<int N> void *RA()
+{
+  return __builtin_return_address(N); // expected-warning{{calling '__builtin_return_address' with a nonzero argument is unsafe}}
+}
+
+void *foo()
+{
+ return RA<2>(); // expected-note{{in instantiation of function template specialization 'RA<2>' requested here}}
+}
+#endif