Split library clangRewrite into clangRewriteCore and clangRewriteFrontend.

This is similar to how we divide up the StaticAnalyzer libraries to separate
core functionality to what is clearly associated with Frontend actions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163050 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 217 insertions, 0 deletions

diff --git a/lib/Rewrite/Frontend/RewriteMacros.cpp b/lib/Rewrite/Frontend/RewriteMacros.cpp
new file mode 100644
index 0000000000..f399dd5d7c
--- /dev/null
+++ b/lib/Rewrite/Frontend/RewriteMacros.cpp
@@ -0,0 +1,217 @@
+//===--- RewriteMacros.cpp - Rewrite macros into their expansions ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This code rewrites macro invocations into their expansions.  This gives you
+// a macro expanded file that retains comments and #includes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/Rewriters.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Path.h"
+#include "llvm/ADT/OwningPtr.h"
+#include <cstdio>
+
+using namespace clang;
+
+/// isSameToken - Return true if the two specified tokens start have the same
+/// content.
+static bool isSameToken(Token &RawTok, Token &PPTok) {
+  // If two tokens have the same kind and the same identifier info, they are
+  // obviously the same.
+  if (PPTok.getKind() == RawTok.getKind() &&
+      PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())
+    return true;
+
+  // Otherwise, if they are different but have the same identifier info, they
+  // are also considered to be the same.  This allows keywords and raw lexed
+  // identifiers with the same name to be treated the same.
+  if (PPTok.getIdentifierInfo() &&
+      PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())
+    return true;
+
+  return false;
+}
+
+
+/// GetNextRawTok - Return the next raw token in the stream, skipping over
+/// comments if ReturnComment is false.
+static const Token &GetNextRawTok(const std::vector<Token> &RawTokens,
+                                  unsigned &CurTok, bool ReturnComment) {
+  assert(CurTok < RawTokens.size() && "Overran eof!");
+
+  // If the client doesn't want comments and we have one, skip it.
+  if (!ReturnComment && RawTokens[CurTok].is(tok::comment))
+    ++CurTok;
+
+  return RawTokens[CurTok++];
+}
+
+
+/// LexRawTokensFromMainFile - Lets all the raw tokens from the main file into
+/// the specified vector.
+static void LexRawTokensFromMainFile(Preprocessor &PP,
+                                     std::vector<Token> &RawTokens) {
+  SourceManager &SM = PP.getSourceManager();
+
+  // Create a lexer to lex all the tokens of the main file in raw mode.  Even
+  // though it is in raw mode, it will not return comments.
+  const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
+  Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOpts());
+
+  // Switch on comment lexing because we really do want them.
+  RawLex.SetCommentRetentionState(true);
+
+  Token RawTok;
+  do {
+    RawLex.LexFromRawLexer(RawTok);
+
+    // If we have an identifier with no identifier info for our raw token, look
+    // up the indentifier info.  This is important for equality comparison of
+    // identifier tokens.
+    if (RawTok.is(tok::raw_identifier))
+      PP.LookUpIdentifierInfo(RawTok);
+
+    RawTokens.push_back(RawTok);
+  } while (RawTok.isNot(tok::eof));
+}
+
+
+/// RewriteMacrosInInput - Implement -rewrite-macros mode.
+void clang::RewriteMacrosInInput(Preprocessor &PP, raw_ostream *OS) {
+  SourceManager &SM = PP.getSourceManager();
+
+  Rewriter Rewrite;
+  Rewrite.setSourceMgr(SM, PP.getLangOpts());
+  RewriteBuffer &RB = Rewrite.getEditBuffer(SM.getMainFileID());
+
+  std::vector<Token> RawTokens;
+  LexRawTokensFromMainFile(PP, RawTokens);
+  unsigned CurRawTok = 0;
+  Token RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+
+
+  // Get the first preprocessing token.
+  PP.EnterMainSourceFile();
+  Token PPTok;
+  PP.Lex(PPTok);
+
+  // Preprocess the input file in parallel with raw lexing the main file. Ignore
+  // all tokens that are preprocessed from a file other than the main file (e.g.
+  // a header).  If we see tokens that are in the preprocessed file but not the
+  // lexed file, we have a macro expansion.  If we see tokens in the lexed file
+  // that aren't in the preprocessed view, we have macros that expand to no
+  // tokens, or macro arguments etc.
+  while (RawTok.isNot(tok::eof) || PPTok.isNot(tok::eof)) {
+    SourceLocation PPLoc = SM.getExpansionLoc(PPTok.getLocation());
+
+    // If PPTok is from a different source file, ignore it.
+    if (!SM.isFromMainFile(PPLoc)) {
+      PP.Lex(PPTok);
+      continue;
+    }
+
+    // If the raw file hits a preprocessor directive, they will be extra tokens
+    // in the raw file that don't exist in the preprocsesed file.  However, we
+    // choose to preserve them in the output file and otherwise handle them
+    // specially.
+    if (RawTok.is(tok::hash) && RawTok.isAtStartOfLine()) {
+      // If this is a #warning directive or #pragma mark (GNU extensions),
+      // comment the line out.
+      if (RawTokens[CurRawTok].is(tok::identifier)) {
+        const IdentifierInfo *II = RawTokens[CurRawTok].getIdentifierInfo();
+        if (II->getName() == "warning") {
+          // Comment out #warning.
+          RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");
+        } else if (II->getName() == "pragma" &&
+                   RawTokens[CurRawTok+1].is(tok::identifier) &&
+                   (RawTokens[CurRawTok+1].getIdentifierInfo()->getName() ==
+                    "mark")) {
+          // Comment out #pragma mark.
+          RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");
+        }
+      }
+
+      // Otherwise, if this is a #include or some other directive, just leave it
+      // in the file by skipping over the line.
+      RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      while (!RawTok.isAtStartOfLine() && RawTok.isNot(tok::eof))
+        RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      continue;
+    }
+
+    // Okay, both tokens are from the same file.  Get their offsets from the
+    // start of the file.
+    unsigned PPOffs = SM.getFileOffset(PPLoc);
+    unsigned RawOffs = SM.getFileOffset(RawTok.getLocation());
+
+    // If the offsets are the same and the token kind is the same, ignore them.
+    if (PPOffs == RawOffs && isSameToken(RawTok, PPTok)) {
+      RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      PP.Lex(PPTok);
+      continue;
+    }
+
+    // If the PP token is farther along than the raw token, something was
+    // deleted.  Comment out the raw token.
+    if (RawOffs <= PPOffs) {
+      // Comment out a whole run of tokens instead of bracketing each one with
+      // comments.  Add a leading space if RawTok didn't have one.
+      bool HasSpace = RawTok.hasLeadingSpace();
+      RB.InsertTextAfter(RawOffs, &" /*"[HasSpace]);
+      unsigned EndPos;
+
+      do {
+        EndPos = RawOffs+RawTok.getLength();
+
+        RawTok = GetNextRawTok(RawTokens, CurRawTok, true);
+        RawOffs = SM.getFileOffset(RawTok.getLocation());
+
+        if (RawTok.is(tok::comment)) {
+          // Skip past the comment.
+          RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+          break;
+        }
+
+      } while (RawOffs <= PPOffs && !RawTok.isAtStartOfLine() &&
+               (PPOffs != RawOffs || !isSameToken(RawTok, PPTok)));
+
+      RB.InsertTextBefore(EndPos, "*/");
+      continue;
+    }
+
+    // Otherwise, there was a replacement an expansion.  Insert the new token
+    // in the output buffer.  Insert the whole run of new tokens at once to get
+    // them in the right order.
+    unsigned InsertPos = PPOffs;
+    std::string Expansion;
+    while (PPOffs < RawOffs) {
+      Expansion += ' ' + PP.getSpelling(PPTok);
+      PP.Lex(PPTok);
+      PPLoc = SM.getExpansionLoc(PPTok.getLocation());
+      PPOffs = SM.getFileOffset(PPLoc);
+    }
+    Expansion += ' ';
+    RB.InsertTextBefore(InsertPos, Expansion);
+  }
+
+  // Get the buffer corresponding to MainFileID.  If we haven't changed it, then
+  // we are done.
+  if (const RewriteBuffer *RewriteBuf =
+      Rewrite.getRewriteBufferFor(SM.getMainFileID())) {
+    //printf("Changed:\n");
+    *OS << std::string(RewriteBuf->begin(), RewriteBuf->end());
+  } else {
+    fprintf(stderr, "No changes\n");
+  }
+  OS->flush();
+}