Add a -rewrite-includes option, which is similar to -rewrite-macros, but only expands #include directives.

Patch contributed by Lubos Lunak (l.lunax@suse.cz).
Review by Matt Beaumont-Gay (matthewbg@google.com).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158093 91177308-0d34-0410-b5e6-96231b3b80d8

Author: dwblaikie

include/clang/Driver/CC1Options.td

@@ -332,6 +332,8 @@ def rewrite_test : Flag<"-rewrite-test">,
   HelpText<"Rewriter playground">;
 def rewrite_macros : Flag<"-rewrite-macros">,
   HelpText<"Expand macros without full preprocessing">;
+def rewrite_includes : Flag<"-rewrite-includes">,
+  HelpText<"Expand includes without full preprocessing">;
 def migrate : Flag<"-migrate">,
   HelpText<"Migrate source code">;
 }

include/clang/Frontend/FrontendOptions.h

@@ -43,6 +43,7 @@ namespace frontend {
     PrintPreamble,          ///< Print the "preamble" of the input file
     PrintPreprocessedInput, ///< -E mode.
     RewriteMacros,          ///< Expand macros but not #includes.
+    RewriteIncludes,        ///< Expand #includes but not macros.
     RewriteObjC,            ///< ObjC->C Rewriter.
     RewriteTest,            ///< Rewriter playground
     RunAnalysis,            ///< Run one or more source code analyses.

include/clang/Lex/Preprocessor.h

@@ -121,6 +121,13 @@ class Preprocessor : public RefCountedBase<Preprocessor> {
   /// DisableMacroExpansion - True if macro expansion is disabled.
   bool DisableMacroExpansion : 1;
 
+  /// MacroExpansionInDirectivesOverride - Temporarily disables
+  /// DisableMacroExpansion (i.e. enables expansion) when parsing preprocessor
+  /// directives.
+  bool MacroExpansionInDirectivesOverride : 1;
+
+  class ResetMacroExpansionHelper;
+
   /// \brief Whether we have already loaded macros from the external source.
   mutable bool ReadMacrosFromExternalSource : 1;
 
@@ -643,6 +650,12 @@ class Preprocessor : public RefCountedBase<Preprocessor> {
     while (Result.getKind() == tok::comment);
   }
 
+  /// Disables macro expansion everywhere except for preprocessor directives.
+  void SetMacroExpansionOnlyInDirectives() {
+    DisableMacroExpansion = true;
+    MacroExpansionInDirectivesOverride = true;
+  }
+
   /// LookAhead - This peeks ahead N tokens and returns that token without
   /// consuming any tokens.  LookAhead(0) returns the next token that would be
   /// returned by Lex(), LookAhead(1) returns the token after it, etc.  This

include/clang/Rewrite/FrontendActions.h

@@ -73,6 +73,11 @@ class RewriteTestAction : public PreprocessorFrontendAction {
   void ExecuteAction();
 };
 
+class RewriteIncludesAction : public PreprocessorFrontendAction {
+protected:
+  void ExecuteAction();
+};
+
 }  // end namespace clang
 
 #endif

include/clang/Rewrite/Rewriters.h

@@ -18,13 +18,18 @@
 
 namespace clang {
 class Preprocessor;
+class PreprocessorOutputOptions;
 
 /// RewriteMacrosInInput - Implement -rewrite-macros mode.
 void RewriteMacrosInInput(Preprocessor &PP, raw_ostream *OS);
 
 /// DoRewriteTest - A simple test for the TokenRewriter class.
 void DoRewriteTest(Preprocessor &PP, raw_ostream *OS);
 
+/// RewriteIncludesInInput - Implement -rewrite-includes mode.
+void RewriteIncludesInInput(Preprocessor &PP, raw_ostream *OS,
+                            const PreprocessorOutputOptions &Opts);
+
 }  // end namespace clang
 
 #endif

lib/Frontend/CompilerInvocation.cpp

@@ -445,6 +445,7 @@ static const char *getActionName(frontend::ActionKind Kind) {
   case frontend::PrintPreamble:          return "-print-preamble";
   case frontend::PrintPreprocessedInput: return "-E";
   case frontend::RewriteMacros:          return "-rewrite-macros";
+  case frontend::RewriteIncludes:        return "-rewrite-includes";
   case frontend::RewriteObjC:            return "-rewrite-objc";
   case frontend::RewriteTest:            return "-rewrite-test";
   case frontend::RunAnalysis:            return "-analyze";
@@ -1435,6 +1436,8 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.ProgramAction = frontend::PrintPreprocessedInput; break;
     case OPT_rewrite_macros:
       Opts.ProgramAction = frontend::RewriteMacros; break;
+    case OPT_rewrite_includes:
+      Opts.ProgramAction = frontend::RewriteIncludes; break;
     case OPT_rewrite_objc:
       Opts.ProgramAction = frontend::RewriteObjC; break;
     case OPT_rewrite_test:

lib/FrontendTool/ExecuteCompilerInvocation.cpp

@@ -73,6 +73,7 @@ static FrontendAction *CreateFrontendBaseAction(CompilerInstance &CI) {
   case PrintPreamble:          return new PrintPreambleAction();
   case PrintPreprocessedInput: return new PrintPreprocessedAction();
   case RewriteMacros:          return new RewriteMacrosAction();
+  case RewriteIncludes:        return new RewriteIncludesAction();
   case RewriteObjC:            return new RewriteObjCAction();
   case RewriteTest:            return new RewriteTestAction();
   case RunAnalysis:            return new ento::AnalysisAction();

lib/Lex/Lexer.cpp

@@ -2022,7 +2022,7 @@ bool Lexer::SaveBCPLComment(Token &Result, const char *CurPtr) {
   // directly.
   FormTokenWithChars(Result, CurPtr, tok::comment);
 
-  if (!ParsingPreprocessorDirective)
+  if (!ParsingPreprocessorDirective || LexingRawMode)
     return true;
 
   // If this BCPL-style comment is in a macro definition, transmogrify it into
@@ -2626,7 +2626,8 @@ void Lexer::LexTokenInternal(Token &Result) {
       ParsingPreprocessorDirective = false;
 
       // Restore comment saving mode, in case it was disabled for directive.
-      SetCommentRetentionState(PP->getCommentRetentionState());
+      if (!LexingRawMode)
+        SetCommentRetentionState(PP->getCommentRetentionState());
 
       // Since we consumed a newline, we are back at the start of a line.
       IsAtStartOfLine = true;

lib/Lex/PPDirectives.cpp

@@ -553,6 +553,21 @@ const FileEntry *Preprocessor::LookupFile(
 // Preprocessor Directive Handling.
 //===----------------------------------------------------------------------===//
 
+class Preprocessor::ResetMacroExpansionHelper {
+public:
+  ResetMacroExpansionHelper(Preprocessor *pp)
+    : PP(pp), save(pp->DisableMacroExpansion) {
+    if (pp->MacroExpansionInDirectivesOverride)
+      pp->DisableMacroExpansion = false;
+  }
+  ~ResetMacroExpansionHelper() {
+    PP->DisableMacroExpansion = save;
+  }
+private:
+  Preprocessor *PP;
+  bool save;
+};
+
 /// HandleDirective - This callback is invoked when the lexer sees a # token
 /// at the start of a line.  This consumes the directive, modifies the
 /// lexer/preprocessor state, and advances the lexer(s) so that the next token
@@ -604,6 +619,10 @@ void Preprocessor::HandleDirective(Token &Result) {
     Diag(Result, diag::ext_embedded_directive);
   }
 
+  // Temporarily enable macro expansion if set so
+  // and reset to previous state when returning from this function.
+  ResetMacroExpansionHelper helper(this);
+
 TryAgain:
   switch (Result.getKind()) {
   case tok::eod:

lib/Lex/Preprocessor.cpp

@@ -86,6 +86,7 @@ Preprocessor::Preprocessor(DiagnosticsEngine &diags, LangOptions &opts,
 
   // Macro expansion is enabled.
   DisableMacroExpansion = false;
+  MacroExpansionInDirectivesOverride = false;
   InMacroArgs = false;
   InMacroArgPreExpansion = false;
   NumCachedTokenLexers = 0;

lib/Rewrite/CMakeLists.txt

@@ -6,6 +6,7 @@ add_clang_library(clangRewrite
   FrontendActions.cpp
   HTMLPrint.cpp
   HTMLRewrite.cpp
+  InclusionRewriter.cpp
   RewriteMacros.cpp
   RewriteModernObjC.cpp
   RewriteObjC.cpp

lib/Rewrite/FrontendActions.cpp

@@ -181,3 +181,12 @@ void RewriteTestAction::ExecuteAction() {
 
   DoRewriteTest(CI.getPreprocessor(), OS);
 }
+
+void RewriteIncludesAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  raw_ostream *OS = CI.createDefaultOutputFile(true, getCurrentFile());
+  if (!OS) return;
+
+  RewriteIncludesInInput(CI.getPreprocessor(), OS,
+                         CI.getPreprocessorOutputOpts());
+}