Introduce a callback to PPCallbacks for lines skipped by the preprocessor.

Patch by Jason Haslam!

llvm-svn: 140612

clang/include/clang/Lex/PPCallbacks.h

@@ -158,6 +158,12 @@ public:
   /// MI is released immediately following this callback.
   virtual void MacroUndefined(const Token &MacroNameTok, const MacroInfo *MI) {
   }
+  
+  /// SourceRangeSkipped - This hook is called when a source range is skipped.
+  /// \param Range The SourceRange that was skipped. The range begins at the
+  /// #if/#else directive and ends after the #endif/#else directive.
+  virtual void SourceRangeSkipped(SourceRange Range) {
+  }
 
   /// If -- This hook is called whenever an #if is seen.
   /// \param Range The SourceRange of the expression being tested.
@@ -286,6 +292,11 @@ public:
     Second->MacroUndefined(MacroNameTok, MI);
   }
 
+  virtual void SourceRangeSkipped(SourceRange Range) {
+    First->SourceRangeSkipped(Range);
+    Second->SourceRangeSkipped(Range);
+  }
+
   /// If -- This hook is called whenever an #if is seen.
   virtual void If(SourceRange Range) {
     First->If(Range);

clang/include/clang/Lex/Preprocessor.h

@@ -1057,7 +1057,8 @@ private:
   /// already seen one so a #else directive is a duplicate.  When this returns,
   /// the caller can lex the first valid token.
   void SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
-                                    bool FoundNonSkipPortion, bool FoundElse);
+                                    bool FoundNonSkipPortion, bool FoundElse,
+                                    SourceLocation ElseLoc = SourceLocation());
 
   /// PTHSkipExcludedConditionalBlock - A fast PTH version of
   ///  SkipExcludedConditionalBlock.

clang/lib/Lex/PPDirectives.cpp

@@ -193,7 +193,8 @@ void Preprocessor::CheckEndOfDirective(const char *DirType, bool EnableMacros) {
 /// the first valid token.
 void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
                                                 bool FoundNonSkipPortion,
-                                                bool FoundElse) {
+                                                bool FoundElse,
+                                                SourceLocation ElseLoc) {
   ++NumSkipped;
   assert(CurTokenLexer == 0 && CurPPLexer && "Lexing a macro, not a file?");
 
@@ -389,6 +390,11 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
   // of the file, just stop skipping and return to lexing whatever came after
   // the #if block.
   CurPPLexer->LexingRawMode = false;
+
+  if (Callbacks) {
+    SourceLocation BeginLoc = ElseLoc.isValid() ? ElseLoc : IfTokenLoc;
+    Callbacks->SourceRangeSkipped(SourceRange(BeginLoc, Tok.getLocation()));
+  }
 }
 
 void Preprocessor::PTHSkipExcludedConditionalBlock() {
@@ -1817,7 +1823,7 @@ void Preprocessor::HandleElseDirective(Token &Result) {
 
   // Finally, skip the rest of the contents of this block.
   SkipExcludedConditionalBlock(CI.IfLoc, /*Foundnonskip*/true,
-                               /*FoundElse*/true);
+                               /*FoundElse*/true, Result.getLocation());
 
   if (Callbacks)
     Callbacks->Else();
@@ -1850,7 +1856,8 @@ void Preprocessor::HandleElifDirective(Token &ElifToken) {
 
   // Finally, skip the rest of the contents of this block.
   SkipExcludedConditionalBlock(CI.IfLoc, /*Foundnonskip*/true,
-                               /*FoundElse*/CI.FoundElse);
+                               /*FoundElse*/CI.FoundElse,
+                               ElifToken.getLocation());
 
   if (Callbacks)
     Callbacks->Elif(SourceRange(ConditionalBegin, ConditionalEnd));