PR14049: Don't say "expanded from macro 'foo'" when 'foo' just happens to be

the LHS of a token paste. Use "expanded from here" instead when we're not sure
it's actually a macro.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169373 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/DiagnosticRenderer.cpp

@@ -47,6 +47,11 @@ static StringRef getImmediateMacroName(SourceLocation Loc,
    while (SM.isMacroArgExpansion(Loc))
      Loc = SM.getImmediateExpansionRange(Loc).first;
 
+   // If the macro's spelling has no FileID, then it's actually a token paste
+   // or stringization (or similar) and not a macro at all.
+   if (!SM.getFileEntryForID(SM.getFileID(SM.getSpellingLoc(Loc))))
+     return StringRef();
+
    // Find the spelling location of the start of the non-argument expansion
    // range. This is where the macro name was spelled in order to begin
    // expanding this macro.
@@ -448,8 +453,11 @@ void DiagnosticRenderer::emitMacroExpansions(SourceLocation Loc,
 
   SmallString<100> MessageStorage;
   llvm::raw_svector_ostream Message(MessageStorage);
-  Message << "expanded from macro '"
-          << getImmediateMacroName(Loc, SM, LangOpts) << "'";
+  StringRef MacroName = getImmediateMacroName(Loc, SM, LangOpts);
+  if (MacroName.empty())
+    Message << "expanded from here";
+  else
+    Message << "expanded from macro '" << MacroName << "'";
   emitDiagnostic(SpellingLoc, DiagnosticsEngine::Note,
                  Message.str(),
                  SpellingRanges, ArrayRef<FixItHint>(), &SM);

test/Misc/diag-macro-backtrace.c

@@ -12,7 +12,7 @@
 #define DROOL WAZ
 #define FOOL DROOL
 
-FOOL
+FOOL;
 
 // CHECK: :15:1: error: expected identifier or '('
 // CHECK: FOOL
@@ -50,4 +50,17 @@ FOOL
 // CHECK: :3:13: note: expanded from macro 'FOO'
 // CHECK: #define FOO 1+"hi" 
 // CHECK:             ^
-// CHECK: 1 error generated.
+
+#define ADD(a, b) a ## #b
+ADD(L, foo)
+// CHECK:    error: expected identifier or '('
+// CHECK:    ADD(L, foo)
+// CHECK: {{^\^}}
+// CHECK:    note: expanded from macro 'ADD'
+// CHECK:    #define ADD(a, b) a ## #b
+// CHECK: {{^                  \^}}
+// CHECK:    note: expanded from here
+// CHECK:    L"foo"
+// CHECK: {{^\^}}
+
+// CHECK: 2 errors generated.

test/Modules/epic-fail.m

@@ -6,7 +6,7 @@
 
 // CHECK: While building module 'Module' imported from
 // CHECK: error: expected ';' after top level declarator
-// CHECK: note: expanded from macro 'getModuleVersion'
+// CHECK: note: expanded from here
 // CHECK: fatal error: could not build module 'Module'
 // CHECK: While building module 'DependsOnModule' imported from
 // CHECK: fatal error: could not build module 'Module'