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

@@ -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;