From 5069aa33b9aab4919322d24ffd9fa24e3b5ccfb6 Mon Sep 17 00:00:00 2001
From: Anna Zaks <ganna@apple.com>
Date: Fri, 3 Feb 2012 01:27:37 +0000
Subject: [PATCH] Do not show macro expansion in strncat warnings, which can be
 defined as a builtin.

llvm-svn: 149657
---
 clang/lib/Sema/SemaChecking.cpp     | 23 ++++++++++++++++-------
 clang/test/Sema/warn-strncat-size.c | 13 ++++++++++++-
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 9dbee1b2b3c6..10cf17321658 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2742,12 +2742,22 @@ void Sema::CheckStrncatArguments(const CallExpr *CE,
   if (PatternType == 0)
     return;
 
+  // Generate the diagnostic.
+  SourceLocation SL = LenArg->getLocStart();
+  SourceRange SR = LenArg->getSourceRange();
+  SourceManager &SM  = PP.getSourceManager();
+
+  // If the function is defined as a builtin macro, do not show macro expansion.
+  if (SM.isMacroArgExpansion(SL)) {
+    SL = SM.getSpellingLoc(SL);
+    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
+                     SM.getSpellingLoc(SR.getEnd()));
+  }
+
   if (PatternType == 1)
-    Diag(DstArg->getLocStart(), diag::warn_strncat_large_size)
-      << LenArg->getSourceRange();
+    Diag(SL, diag::warn_strncat_large_size) << SR;
   else
-    Diag(DstArg->getLocStart(), diag::warn_strncat_src_size)
-      << LenArg->getSourceRange();
+    Diag(SL, diag::warn_strncat_src_size) << SR;
 
   // Output a FIXIT hint if the destination is an array (rather than a
   // pointer to an array).  This could be enhanced to handle some
@@ -2773,9 +2783,8 @@ void Sema::CheckStrncatArguments(const CallExpr *CE,
   DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
   OS << ") - 1";
 
-  Diag(LenArg->getLocStart(), diag::note_strncat_wrong_size)
-    << FixItHint::CreateReplacement(LenArg->getSourceRange(),
-                                    OS.str());
+  Diag(SL, diag::note_strncat_wrong_size)
+    << FixItHint::CreateReplacement(SR, OS.str());
 }
 
 //===--- CHECK: Return Address of Stack Variable --------------------------===//
diff --git a/clang/test/Sema/warn-strncat-size.c b/clang/test/Sema/warn-strncat-size.c
index 4233f25d5a45..7157edffea47 100644
--- a/clang/test/Sema/warn-strncat-size.c
+++ b/clang/test/Sema/warn-strncat-size.c
@@ -1,9 +1,20 @@
 // RUN: %clang_cc1 -Wstrncat-size -verify -fsyntax-only %s
+// RUN: %clang_cc1 -DUSE_BUILTINS -Wstrncat-size -verify -fsyntax-only %s
+// RUN: %clang_cc1 -fsyntax-only -Wstrncat-size -fixit -x c %s
+// RUN: %clang_cc1 -DUSE_BUILTINS -fsyntax-only -Wstrncat-size -fixit -x c %s
 
 typedef __SIZE_TYPE__ size_t;
-char  *strncat(char *, const char *, size_t);
 size_t strlen (const char *s);
 
+#ifdef USE_BUILTINS
+# define BUILTIN(f) __builtin_ ## f
+#else
+# define BUILTIN(f) f
+#endif
+
+#define strncat BUILTIN(strncat)
+char *strncat(char *restrict s1, const char *restrict s2, size_t n);
+
 struct {
   char f1[100];
   char f2[100][3];