From 724a1ca207099b2b5a4c11f5dc57f194e3a4885f Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sun, 16 Oct 2011 09:39:09 +0000
Subject: [PATCH] Hoist the logic I added to compute the macro name into a
 helper function. No functionality changed.

llvm-svn: 142128
---
 clang/lib/Frontend/TextDiagnostic.cpp | 46 +++++++++++++++++----------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index 8dab0afcac3c..8b901ae310ee 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -389,6 +389,35 @@ static bool printWordWrapped(raw_ostream &OS, StringRef Str,
   return Wrapped;
 }
 
+/// \brief Retrieve the name of the immediate macro expansion.
+///
+/// This routine starts from a source location, and finds the name of the macro
+/// responsible for its immediate expansion. It looks through any intervening
+/// macro argument expansions to compute this. It returns a StringRef which
+/// refers to the SourceManager-owned buffer of the source where that macro
+/// name is spelled. Thus, the result shouldn't out-live that SourceManager.
+///
+static StringRef getImmediateMacroName(SourceLocation Loc,
+                                       const SourceManager &SM,
+                                       const LangOptions &LangOpts) {
+  assert(Loc.isMacroID() && "Only reasonble to call this on macros");
+  // Walk past macro argument expanions.
+  while (SM.isMacroArgExpansion(Loc))
+    Loc = SM.getImmediateExpansionRange(Loc).first;
+
+  // 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.
+  Loc = SM.getSpellingLoc(SM.getImmediateExpansionRange(Loc).first);
+
+  // Dig out the buffer where the macro name was spelled and the extents of the
+  // name so that we can render it into the expansion note.
+  std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(Loc);
+  unsigned MacroTokenLength = Lexer::MeasureTokenLength(Loc, SM, LangOpts);
+  StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
+  return ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
+}
+
 TextDiagnostic::TextDiagnostic(raw_ostream &OS,
                                const SourceManager &SM,
                                const LangOptions &LangOpts,
@@ -729,25 +758,10 @@ void TextDiagnostic::emitMacroExpansionsAndCarets(
     return;
   }
 
-  // Walk past macro argument expanions.
-  while (SM.isMacroArgExpansion(MacroLoc))
-    MacroLoc = SM.getImmediateExpansionRange(MacroLoc).first;
-
-  // 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.
-  MacroLoc = SM.getSpellingLoc(SM.getImmediateExpansionRange(MacroLoc).first);
-
-  // Dig out the buffer where the macro name was spelled and the extents of the
-  // name so that we can render it into the expansion note.
-  std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(MacroLoc);
-  unsigned MacroTokenLength = Lexer::MeasureTokenLength(MacroLoc, SM, LangOpts);
-  StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
-
   llvm::SmallString<100> MessageStorage;
   llvm::raw_svector_ostream Message(MessageStorage);
   Message << "expanded from macro: "
-          << ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
+          << getImmediateMacroName(MacroLoc, SM, LangOpts);
   emitDiagnostic(SM.getSpellingLoc(Loc), DiagnosticsEngine::Note,
                  Message.str(),
                  Ranges, ArrayRef<FixItHint>());