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llvm-project/clang/lib/Rewrite/Frontend/InclusionRewriter.cpp

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//===--- InclusionRewriter.cpp - Rewrite includes 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 include invocations into their expansions. This gives you
// a file with all included files merged into it.
//
//===----------------------------------------------------------------------===//
#include "clang/Rewrite/Frontend/Rewriters.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Frontend/PreprocessorOutputOptions.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace llvm;
namespace {
class InclusionRewriter : public PPCallbacks {
/// Information about which #includes were actually performed,
/// created by preprocessor callbacks.
struct FileChange {
SourceLocation From;
FileID Id;
SrcMgr::CharacteristicKind FileType;
FileChange(SourceLocation From) : From(From) {
}
};
Preprocessor &PP; ///< Used to find inclusion directives.
SourceManager &SM; ///< Used to read and manage source files.
raw_ostream &OS; ///< The destination stream for rewritten contents.
bool ShowLineMarkers; ///< Show #line markers.
bool UseLineDirective; ///< Use of line directives or line markers.
typedef std::map<unsigned, FileChange> FileChangeMap;
FileChangeMap FileChanges; /// Tracks which files were included where.
/// Used transitively for building up the FileChanges mapping over the
/// various \c PPCallbacks callbacks.
FileChangeMap::iterator LastInsertedFileChange;
public:
InclusionRewriter(Preprocessor &PP, raw_ostream &OS, bool ShowLineMarkers);
bool Process(FileID FileId, SrcMgr::CharacteristicKind FileType);
private:
virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
SrcMgr::CharacteristicKind FileType,
FileID PrevFID);
virtual void FileSkipped(const FileEntry &ParentFile,
const Token &FilenameTok,
SrcMgr::CharacteristicKind FileType);
virtual void InclusionDirective(SourceLocation HashLoc,
const Token &IncludeTok,
StringRef FileName,
bool IsAngled,
CharSourceRange FilenameRange,
const FileEntry *File,
StringRef SearchPath,
StringRef RelativePath,
const Module *Imported);
void WriteLineInfo(const char *Filename, int Line,
SrcMgr::CharacteristicKind FileType,
StringRef EOL, StringRef Extra = StringRef());
void OutputContentUpTo(const MemoryBuffer &FromFile,
unsigned &WriteFrom, unsigned WriteTo,
StringRef EOL, int &lines,
bool EnsureNewline = false);
void CommentOutDirective(Lexer &DirectivesLex, const Token &StartToken,
const MemoryBuffer &FromFile, StringRef EOL,
unsigned &NextToWrite, int &Lines);
const FileChange *FindFileChangeLocation(SourceLocation Loc) const;
StringRef NextIdentifierName(Lexer &RawLex, Token &RawToken);
};
} // end anonymous namespace
/// Initializes an InclusionRewriter with a \p PP source and \p OS destination.
InclusionRewriter::InclusionRewriter(Preprocessor &PP, raw_ostream &OS,
bool ShowLineMarkers)
: PP(PP), SM(PP.getSourceManager()), OS(OS),
ShowLineMarkers(ShowLineMarkers),
LastInsertedFileChange(FileChanges.end()) {
// If we're in microsoft mode, use normal #line instead of line markers.
UseLineDirective = PP.getLangOpts().MicrosoftExt;
}
/// Write appropriate line information as either #line directives or GNU line
/// markers depending on what mode we're in, including the \p Filename and
/// \p Line we are located at, using the specified \p EOL line separator, and
/// any \p Extra context specifiers in GNU line directives.
void InclusionRewriter::WriteLineInfo(const char *Filename, int Line,
SrcMgr::CharacteristicKind FileType,
StringRef EOL, StringRef Extra) {
if (!ShowLineMarkers)
return;
if (UseLineDirective) {
OS << "#line" << ' ' << Line << ' ' << '"' << Filename << '"';
} else {
// Use GNU linemarkers as described here:
// http://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html
OS << '#' << ' ' << Line << ' ' << '"' << Filename << '"';
if (!Extra.empty())
OS << Extra;
if (FileType == SrcMgr::C_System)
// "`3' This indicates that the following text comes from a system header
// file, so certain warnings should be suppressed."
OS << " 3";
else if (FileType == SrcMgr::C_ExternCSystem)
// as above for `3', plus "`4' This indicates that the following text
// should be treated as being wrapped in an implicit extern "C" block."
OS << " 3 4";
}
OS << EOL;
}
/// FileChanged - Whenever the preprocessor enters or exits a #include file
/// it invokes this handler.
void InclusionRewriter::FileChanged(SourceLocation Loc,
FileChangeReason Reason,
SrcMgr::CharacteristicKind NewFileType,
FileID) {
if (Reason != EnterFile)
return;
if (LastInsertedFileChange == FileChanges.end())
// we didn't reach this file (eg: the main file) via an inclusion directive
return;
LastInsertedFileChange->second.Id = FullSourceLoc(Loc, SM).getFileID();
LastInsertedFileChange->second.FileType = NewFileType;
LastInsertedFileChange = FileChanges.end();
}
/// Called whenever an inclusion is skipped due to canonical header protection
/// macros.
void InclusionRewriter::FileSkipped(const FileEntry &/*ParentFile*/,
const Token &/*FilenameTok*/,
SrcMgr::CharacteristicKind /*FileType*/) {
assert(LastInsertedFileChange != FileChanges.end() && "A file, that wasn't "
"found via an inclusion directive, was skipped");
FileChanges.erase(LastInsertedFileChange);
LastInsertedFileChange = FileChanges.end();
}
/// This should be called whenever the preprocessor encounters include
/// directives. It does not say whether the file has been included, but it
/// provides more information about the directive (hash location instead
/// of location inside the included file). It is assumed that the matching
/// FileChanged() or FileSkipped() is called after this.
void InclusionRewriter::InclusionDirective(SourceLocation HashLoc,
const Token &/*IncludeTok*/,
StringRef /*FileName*/,
bool /*IsAngled*/,
CharSourceRange /*FilenameRange*/,
const FileEntry * /*File*/,
StringRef /*SearchPath*/,
StringRef /*RelativePath*/,
const Module * /*Imported*/) {
assert(LastInsertedFileChange == FileChanges.end() && "Another inclusion "
"directive was found before the previous one was processed");
std::pair<FileChangeMap::iterator, bool> p = FileChanges.insert(
std::make_pair(HashLoc.getRawEncoding(), FileChange(HashLoc)));
assert(p.second && "Unexpected revisitation of the same include directive");
LastInsertedFileChange = p.first;
}
/// Simple lookup for a SourceLocation (specifically one denoting the hash in
/// an inclusion directive) in the map of inclusion information, FileChanges.
const InclusionRewriter::FileChange *
InclusionRewriter::FindFileChangeLocation(SourceLocation Loc) const {
FileChangeMap::const_iterator I = FileChanges.find(Loc.getRawEncoding());
if (I != FileChanges.end())
return &I->second;
return NULL;
}
/// Detect the likely line ending style of \p FromFile by examining the first
/// newline found within it.
static StringRef DetectEOL(const MemoryBuffer &FromFile) {
// detect what line endings the file uses, so that added content does not mix
// the style
const char *Pos = strchr(FromFile.getBufferStart(), '\n');
if (Pos == NULL)
return "\n";
if (Pos + 1 < FromFile.getBufferEnd() && Pos[1] == '\r')
return "\n\r";
if (Pos - 1 >= FromFile.getBufferStart() && Pos[-1] == '\r')
return "\r\n";
return "\n";
}
/// Writes out bytes from \p FromFile, starting at \p NextToWrite and ending at
/// \p WriteTo - 1.
void InclusionRewriter::OutputContentUpTo(const MemoryBuffer &FromFile,
unsigned &WriteFrom, unsigned WriteTo,
StringRef EOL, int &Line,
bool EnsureNewline) {
if (WriteTo <= WriteFrom)
return;
OS.write(FromFile.getBufferStart() + WriteFrom, WriteTo - WriteFrom);
// count lines manually, it's faster than getPresumedLoc()
Line += std::count(FromFile.getBufferStart() + WriteFrom,
FromFile.getBufferStart() + WriteTo, '\n');
if (EnsureNewline) {
char LastChar = FromFile.getBufferStart()[WriteTo - 1];
if (LastChar != '\n' && LastChar != '\r')
OS << EOL;
}
WriteFrom = WriteTo;
}
/// Print characters from \p FromFile starting at \p NextToWrite up until the
/// inclusion directive at \p StartToken, then print out the inclusion
/// inclusion directive disabled by a #if directive, updating \p NextToWrite
/// and \p Line to track the number of source lines visited and the progress
/// through the \p FromFile buffer.
void InclusionRewriter::CommentOutDirective(Lexer &DirectiveLex,
const Token &StartToken,
const MemoryBuffer &FromFile,
StringRef EOL,
unsigned &NextToWrite, int &Line) {
OutputContentUpTo(FromFile, NextToWrite,
SM.getFileOffset(StartToken.getLocation()), EOL, Line);
Token DirectiveToken;
do {
DirectiveLex.LexFromRawLexer(DirectiveToken);
} while (!DirectiveToken.is(tok::eod) && DirectiveToken.isNot(tok::eof));
OS << "#if 0 /* expanded by -frewrite-includes */" << EOL;
OutputContentUpTo(FromFile, NextToWrite,
SM.getFileOffset(DirectiveToken.getLocation()) + DirectiveToken.getLength(),
EOL, Line);
OS << "#endif /* expanded by -frewrite-includes */" << EOL;
}
/// Find the next identifier in the pragma directive specified by \p RawToken.
StringRef InclusionRewriter::NextIdentifierName(Lexer &RawLex,
Token &RawToken) {
RawLex.LexFromRawLexer(RawToken);
if (RawToken.is(tok::raw_identifier))
PP.LookUpIdentifierInfo(RawToken);
if (RawToken.is(tok::identifier))
return RawToken.getIdentifierInfo()->getName();
return StringRef();
}
/// Use a raw lexer to analyze \p FileId, inccrementally copying parts of it
/// and including content of included files recursively.
bool InclusionRewriter::Process(FileID FileId,
SrcMgr::CharacteristicKind FileType)
{
bool Invalid;
const MemoryBuffer &FromFile = *SM.getBuffer(FileId, &Invalid);
if (Invalid) // invalid inclusion
return true;
const char *FileName = FromFile.getBufferIdentifier();
Lexer RawLex(FileId, &FromFile, PP.getSourceManager(), PP.getLangOpts());
RawLex.SetCommentRetentionState(false);
StringRef EOL = DetectEOL(FromFile);
// Per the GNU docs: "1" indicates the start of a new file.
WriteLineInfo(FileName, 1, FileType, EOL, " 1");
if (SM.getFileIDSize(FileId) == 0)
return true;
// The next byte to be copied from the source file
unsigned NextToWrite = 0;
int Line = 1; // The current input file line number.
Token RawToken;
RawLex.LexFromRawLexer(RawToken);
// TODO: Consider adding a switch that strips possibly unimportant content,
// such as comments, to reduce the size of repro files.
while (RawToken.isNot(tok::eof)) {
if (RawToken.is(tok::hash) && RawToken.isAtStartOfLine()) {
RawLex.setParsingPreprocessorDirective(true);
Token HashToken = RawToken;
RawLex.LexFromRawLexer(RawToken);
if (RawToken.is(tok::raw_identifier))
PP.LookUpIdentifierInfo(RawToken);
if (RawToken.is(tok::identifier)) {
switch (RawToken.getIdentifierInfo()->getPPKeywordID()) {
case tok::pp_include:
case tok::pp_include_next:
case tok::pp_import: {
CommentOutDirective(RawLex, HashToken, FromFile, EOL, NextToWrite,
Line);
if (const FileChange *Change = FindFileChangeLocation(
HashToken.getLocation())) {
// now include and recursively process the file
if (Process(Change->Id, Change->FileType))
// and set lineinfo back to this file, if the nested one was
// actually included
// `2' indicates returning to a file (after having included
// another file.
WriteLineInfo(FileName, Line, FileType, EOL, " 2");
} else
// fix up lineinfo (since commented out directive changed line
// numbers) for inclusions that were skipped due to header guards
WriteLineInfo(FileName, Line, FileType, EOL);
break;
}
case tok::pp_pragma: {
StringRef Identifier = NextIdentifierName(RawLex, RawToken);
if (Identifier == "clang" || Identifier == "GCC") {
if (NextIdentifierName(RawLex, RawToken) == "system_header") {
// keep the directive in, commented out
CommentOutDirective(RawLex, HashToken, FromFile, EOL,
NextToWrite, Line);
// update our own type
FileType = SM.getFileCharacteristic(RawToken.getLocation());
WriteLineInfo(FileName, Line, FileType, EOL);
}
} else if (Identifier == "once") {
// keep the directive in, commented out
CommentOutDirective(RawLex, HashToken, FromFile, EOL,
NextToWrite, Line);
WriteLineInfo(FileName, Line, FileType, EOL);
}
break;
}
default:
break;
}
}
RawLex.setParsingPreprocessorDirective(false);
}
RawLex.LexFromRawLexer(RawToken);
}
OutputContentUpTo(FromFile, NextToWrite,
SM.getFileOffset(SM.getLocForEndOfFile(FileId)) + 1, EOL, Line,
/*EnsureNewline*/true);
return true;
}
/// InclusionRewriterInInput - Implement -frewrite-includes mode.
void clang::RewriteIncludesInInput(Preprocessor &PP, raw_ostream *OS,
const PreprocessorOutputOptions &Opts) {
SourceManager &SM = PP.getSourceManager();
InclusionRewriter *Rewrite = new InclusionRewriter(PP, *OS,
Opts.ShowLineMarkers);
PP.addPPCallbacks(Rewrite);
// First let the preprocessor process the entire file and call callbacks.
// Callbacks will record which #include's were actually performed.
PP.EnterMainSourceFile();
Token Tok;
// Only preprocessor directives matter here, so disable macro expansion
// everywhere else as an optimization.
// TODO: It would be even faster if the preprocessor could be switched
// to a mode where it would parse only preprocessor directives and comments,
// nothing else matters for parsing or processing.
PP.SetMacroExpansionOnlyInDirectives();
do {
PP.Lex(Tok);
} while (Tok.isNot(tok::eof));
Rewrite->Process(SM.getMainFileID(), SrcMgr::C_User);
OS->flush();
}
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