Revert "Make -Wstring-plus-int warns even if when the result is not out of bounds"

This reverts commit r349054.

It's causing:

FAILED: tools/clang/bindings/python/tests/CMakeFiles/check-clang-python
FAIL: test_diagnostic_range (tests.cindex.test_diagnostics.TestDiagnostics)
----------------------------------------------------------------------
Traceback (most recent call last):
  File
  "/Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/bindings/python/tests/cindex/test_diagnostics.py",
  line 55, in test_diagnostic_range
      self.assertEqual(len(tu.diagnostics), 1)
      AssertionError: 2 != 1

======================================================================
FAIL: test_diagnostic_warning (tests.cindex.test_diagnostics.TestDiagnostics)
----------------------------------------------------------------------
Traceback (most recent call last):
  File
  "/Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/bindings/python/tests/cindex/test_diagnostics.py",
  line 18, in test_diagnostic_warning
      self.assertEqual(len(tu.diagnostics), 2)
      AssertionError: 1 != 2

llvm-svn: 349117

2 files changed, 22 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 0771e7e1df4..4ba0fb12e70 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -9135,6 +9135,16 @@ static void diagnoseStringPlusInt(Sema &Self, SourceLocation OpLoc,
   if (!IsStringPlusInt || IndexExpr->isValueDependent())
     return;
 
+  Expr::EvalResult Result;
+  if (IndexExpr->EvaluateAsInt(Result, Self.getASTContext())) {
+    llvm::APSInt index = Result.Val.getInt();
+    unsigned StrLenWithNull = StrExpr->getLength() + 1;
+    if (index.isNonNegative() &&
+        index <= llvm::APSInt(llvm::APInt(index.getBitWidth(), StrLenWithNull),
+                              index.isUnsigned()))
+      return;
+  }
+
   SourceRange DiagRange(LHSExpr->getBeginLoc(), RHSExpr->getEndLoc());
   Self.Diag(OpLoc, diag::warn_string_plus_int)
       << DiagRange << IndexExpr->IgnoreImpCasts()->getType();
diff --git a/clang/test/SemaCXX/string-plus-int.cpp b/clang/test/SemaCXX/string-plus-int.cpp
index 448fb49fb49..fe9c7194969 100644
--- a/clang/test/SemaCXX/string-plus-int.cpp
+++ b/clang/test/SemaCXX/string-plus-int.cpp
@@ -31,36 +31,37 @@ void f(int index) {
   consume("foo" + 5);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
   consume("foo" + index);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
   consume("foo" + kMyEnum);  // expected-warning {{adding 'MyEnum' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-  consume("foo" + kMySmallEnum); // expected-warning {{adding 'MyEnum' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
 
   consume(5 + "foo");  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
   consume(index + "foo");  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
   consume(kMyEnum + "foo");  // expected-warning {{adding 'MyEnum' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-  consume(kMySmallEnum + "foo"); // expected-warning {{adding 'MyEnum' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
 
   // FIXME: suggest replacing with "foo"[5]
   consumeChar(*("foo" + 5));  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
   consumeChar(*(5 + "foo"));  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
 
   consume(L"foo" + 5);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-  consume(L"foo" + 2); // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-
-  consume("foo" + 3);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-  consume("foo" + 4);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-  consume("\pfoo" + 4);  // expected-warning {{adding 'int' to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
-
-  #define A "foo"
-  #define B "bar"
-  consume(A B + sizeof(A) - 1); // expected-warning {{to a string does not append to the string}} expected-note {{use array indexing to silence this warning}}
 
   // Should not warn.
   consume(&("foo"[3]));
   consume(&("foo"[index]));
   consume(&("foo"[kMyEnum]));
+  consume("foo" + kMySmallEnum);
+  consume(kMySmallEnum + "foo");
 
+  consume(L"foo" + 2);
+
+  consume("foo" + 3);  // Points at the \0
+  consume("foo" + 4);  // Points 1 past the \0, which is legal too.
+  consume("\pfoo" + 4);  // Pascal strings don't have a trailing \0, but they
+                         // have a leading length byte, so this is fine too.
 
   consume("foo" + kMyOperatorOverloadedEnum);
   consume(kMyOperatorOverloadedEnum + "foo");
+
+  #define A "foo"
+  #define B "bar"
+  consume(A B + sizeof(A) - 1);
 }
 
 template <typename T>