216 lines · cpp
1//===--- RewriteMacros.cpp - Rewrite macros into their expansions ---------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This code rewrites macro invocations into their expansions. This gives you10// a macro expanded file that retains comments and #includes.11//12//===----------------------------------------------------------------------===//13 14#include "clang/Basic/SourceManager.h"15#include "clang/Lex/Preprocessor.h"16#include "clang/Rewrite/Core/Rewriter.h"17#include "clang/Rewrite/Frontend/Rewriters.h"18#include "llvm/ADT/RewriteBuffer.h"19#include <cstdio>20 21using namespace clang;22using llvm::RewriteBuffer;23 24/// isSameToken - Return true if the two specified tokens start have the same25/// content.26static bool isSameToken(Token &RawTok, Token &PPTok) {27 // If two tokens have the same kind and the same identifier info, they are28 // obviously the same.29 if (PPTok.getKind() == RawTok.getKind() &&30 PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())31 return true;32 33 // Otherwise, if they are different but have the same identifier info, they34 // are also considered to be the same. This allows keywords and raw lexed35 // identifiers with the same name to be treated the same.36 if (PPTok.getIdentifierInfo() &&37 PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())38 return true;39 40 return false;41}42 43 44/// GetNextRawTok - Return the next raw token in the stream, skipping over45/// comments if ReturnComment is false.46static const Token &GetNextRawTok(const std::vector<Token> &RawTokens,47 unsigned &CurTok, bool ReturnComment) {48 assert(CurTok < RawTokens.size() && "Overran eof!");49 50 // If the client doesn't want comments and we have one, skip it.51 if (!ReturnComment && RawTokens[CurTok].is(tok::comment))52 ++CurTok;53 54 return RawTokens[CurTok++];55}56 57 58/// LexRawTokensFromMainFile - Lets all the raw tokens from the main file into59/// the specified vector.60static void LexRawTokensFromMainFile(Preprocessor &PP,61 std::vector<Token> &RawTokens) {62 SourceManager &SM = PP.getSourceManager();63 64 // Create a lexer to lex all the tokens of the main file in raw mode. Even65 // though it is in raw mode, it will not return comments.66 llvm::MemoryBufferRef FromFile = SM.getBufferOrFake(SM.getMainFileID());67 Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOpts());68 69 // Switch on comment lexing because we really do want them.70 RawLex.SetCommentRetentionState(true);71 72 Token RawTok;73 do {74 RawLex.LexFromRawLexer(RawTok);75 76 // If we have an identifier with no identifier info for our raw token, look77 // up the identifier info. This is important for equality comparison of78 // identifier tokens.79 if (RawTok.is(tok::raw_identifier))80 PP.LookUpIdentifierInfo(RawTok);81 82 RawTokens.push_back(RawTok);83 } while (RawTok.isNot(tok::eof));84}85 86 87/// RewriteMacrosInInput - Implement -rewrite-macros mode.88void clang::RewriteMacrosInInput(Preprocessor &PP, raw_ostream *OS) {89 SourceManager &SM = PP.getSourceManager();90 91 Rewriter Rewrite;92 Rewrite.setSourceMgr(SM, PP.getLangOpts());93 RewriteBuffer &RB = Rewrite.getEditBuffer(SM.getMainFileID());94 95 std::vector<Token> RawTokens;96 LexRawTokensFromMainFile(PP, RawTokens);97 unsigned CurRawTok = 0;98 Token RawTok = GetNextRawTok(RawTokens, CurRawTok, false);99 100 101 // Get the first preprocessing token.102 PP.EnterMainSourceFile();103 Token PPTok;104 PP.Lex(PPTok);105 106 // Preprocess the input file in parallel with raw lexing the main file. Ignore107 // all tokens that are preprocessed from a file other than the main file (e.g.108 // a header). If we see tokens that are in the preprocessed file but not the109 // lexed file, we have a macro expansion. If we see tokens in the lexed file110 // that aren't in the preprocessed view, we have macros that expand to no111 // tokens, or macro arguments etc.112 while (RawTok.isNot(tok::eof) || PPTok.isNot(tok::eof)) {113 SourceLocation PPLoc = SM.getExpansionLoc(PPTok.getLocation());114 115 // If PPTok is from a different source file, ignore it.116 if (!SM.isWrittenInMainFile(PPLoc)) {117 PP.Lex(PPTok);118 continue;119 }120 121 // If the raw file hits a preprocessor directive, they will be extra tokens122 // in the raw file that don't exist in the preprocsesed file. However, we123 // choose to preserve them in the output file and otherwise handle them124 // specially.125 if (RawTok.is(tok::hash) && RawTok.isAtStartOfLine()) {126 // If this is a #warning directive or #pragma mark (GNU extensions),127 // comment the line out.128 if (RawTokens[CurRawTok].is(tok::identifier)) {129 const IdentifierInfo *II = RawTokens[CurRawTok].getIdentifierInfo();130 if (II->getName() == "warning") {131 // Comment out #warning.132 RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");133 } else if (II->getName() == "pragma" &&134 RawTokens[CurRawTok+1].is(tok::identifier) &&135 (RawTokens[CurRawTok+1].getIdentifierInfo()->getName() ==136 "mark")) {137 // Comment out #pragma mark.138 RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");139 }140 }141 142 // Otherwise, if this is a #include or some other directive, just leave it143 // in the file by skipping over the line.144 RawTok = GetNextRawTok(RawTokens, CurRawTok, false);145 while (!RawTok.isAtStartOfLine() && RawTok.isNot(tok::eof))146 RawTok = GetNextRawTok(RawTokens, CurRawTok, false);147 continue;148 }149 150 // Okay, both tokens are from the same file. Get their offsets from the151 // start of the file.152 unsigned PPOffs = SM.getFileOffset(PPLoc);153 unsigned RawOffs = SM.getFileOffset(RawTok.getLocation());154 155 // If the offsets are the same and the token kind is the same, ignore them.156 if (PPOffs == RawOffs && isSameToken(RawTok, PPTok)) {157 RawTok = GetNextRawTok(RawTokens, CurRawTok, false);158 PP.Lex(PPTok);159 continue;160 }161 162 // If the PP token is farther along than the raw token, something was163 // deleted. Comment out the raw token.164 if (RawOffs <= PPOffs) {165 // Comment out a whole run of tokens instead of bracketing each one with166 // comments. Add a leading space if RawTok didn't have one.167 bool HasSpace = RawTok.hasLeadingSpace();168 RB.InsertTextAfter(RawOffs, &" /*"[HasSpace]);169 unsigned EndPos;170 171 do {172 EndPos = RawOffs+RawTok.getLength();173 174 RawTok = GetNextRawTok(RawTokens, CurRawTok, true);175 RawOffs = SM.getFileOffset(RawTok.getLocation());176 177 if (RawTok.is(tok::comment)) {178 // Skip past the comment.179 RawTok = GetNextRawTok(RawTokens, CurRawTok, false);180 break;181 }182 183 } while (RawOffs <= PPOffs && !RawTok.isAtStartOfLine() &&184 (PPOffs != RawOffs || !isSameToken(RawTok, PPTok)));185 186 RB.InsertTextBefore(EndPos, "*/");187 continue;188 }189 190 // Otherwise, there was a replacement an expansion. Insert the new token191 // in the output buffer. Insert the whole run of new tokens at once to get192 // them in the right order.193 unsigned InsertPos = PPOffs;194 std::string Expansion;195 while (PPOffs < RawOffs) {196 Expansion += ' ' + PP.getSpelling(PPTok);197 PP.Lex(PPTok);198 PPLoc = SM.getExpansionLoc(PPTok.getLocation());199 PPOffs = SM.getFileOffset(PPLoc);200 }201 Expansion += ' ';202 RB.InsertTextBefore(InsertPos, Expansion);203 }204 205 // Get the buffer corresponding to MainFileID. If we haven't changed it, then206 // we are done.207 if (const RewriteBuffer *RewriteBuf =208 Rewrite.getRewriteBufferFor(SM.getMainFileID())) {209 //printf("Changed:\n");210 *OS << std::string(RewriteBuf->begin(), RewriteBuf->end());211 } else {212 fprintf(stderr, "No changes\n");213 }214 OS->flush();215}216