From 7f4153dbee0c01ca839f04fd10eb939785914d8e Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 28 May 2009 05:39:39 +0000
Subject: [PATCH] fix the "pasting formed 'a]', an invalid preprocessing token"
 diagnostic to include the full instantiation location for the invalid paste. 
 For:

#define foo(a, b)  a ## b
#define bar(x) foo(x, ])
bar(a)
bar(zdy)

Instead of:

t.c:3:22: error: pasting formed 'a]', an invalid preprocessing token
#define foo(a, b)  a ## b
                     ^
t.c:3:22: error: pasting formed 'zdy]', an invalid preprocessing token

we now produce:

t.c:7:1: error: pasting formed 'a]', an invalid preprocessing token
bar(a)
^
t.c:4:16: note: instantiated from:
#define bar(x) foo(x, ])
               ^
t.c:3:22: note: instantiated from:
#define foo(a, b)  a ## b
                     ^
t.c:8:1: error: pasting formed 'zdy]', an invalid preprocessing token
bar(zdy)
^
t.c:4:16: note: instantiated from:
#define bar(x) foo(x, ])
               ^
t.c:3:22: note: instantiated from:
#define foo(a, b)  a ## b
                     ^

llvm-svn: 72519
---
 clang/lib/Lex/TokenLexer.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Lex/TokenLexer.cpp b/clang/lib/Lex/TokenLexer.cpp
index 318c57cc5f26..f9f93867c853 100644
--- a/clang/lib/Lex/TokenLexer.cpp
+++ b/clang/lib/Lex/TokenLexer.cpp
@@ -471,9 +471,16 @@ bool TokenLexer::PasteTokens(Token &Tok) {
         }
       
         // Do not emit the warning when preprocessing assembler code.
-        if (!PP.getLangOptions().AsmPreprocessor)
-          PP.Diag(PasteOpLoc, diag::err_pp_bad_paste)
+        if (!PP.getLangOptions().AsmPreprocessor) {
+          // Explicitly convert the token location to have proper instantiation
+          // information so that the user knows where it came from.
+          SourceManager &SM = PP.getSourceManager();
+          SourceLocation Loc =
+            SM.createInstantiationLoc(PasteOpLoc, InstantiateLocStart,
+                                      InstantiateLocEnd, 2);
+          PP.Diag(Loc, diag::err_pp_bad_paste)
             << std::string(Buffer.begin(), Buffer.end());
+        }
         
         // Do not consume the RHS.
         --CurToken;