Support strlen() and __builtin_strlen() as constant expressions with
the call argument is a string literal. Fixes
<rdar://problem/8413477>.
llvm-svn: 113580
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 04aea9e..7736581 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1159,6 +1159,24 @@
case Builtin::BI__builtin_expect:
return Visit(E->getArg(0));
+
+ case Builtin::BIstrlen:
+ case Builtin::BI__builtin_strlen:
+ // As an extension, we support strlen() and __builtin_strlen() as constant
+ // expressions when the argument is a string literal.
+ if (StringLiteral *S
+ = dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) {
+ // The string literal may have embedded null characters. Find the first
+ // one and truncate there.
+ llvm::StringRef Str = S->getString();
+ llvm::StringRef::size_type Pos = Str.find(0);
+ if (Pos != llvm::StringRef::npos)
+ Str = Str.substr(0, Pos);
+
+ return Success(Str.size(), E);
+ }
+
+ return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
}