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llvm-project/clang/Driver/PrintPreprocessedOutput.cpp

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//===--- PrintPreprocessedOutput.cpp - Implement the -E mode --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This code simply runs the preprocessor on the input file and prints out the
// result. This is the traditional behavior of the -E option.
//
//===----------------------------------------------------------------------===//
#include "clang.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/Pragma.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Config/config.h"
#include <cstdio>
using namespace clang;
//===----------------------------------------------------------------------===//
// Simple buffered I/O
//===----------------------------------------------------------------------===//
//
// Empirically, iostream is over 30% slower than stdio for this workload, and
// stdio itself isn't very well suited. The problem with stdio is use of
// putchar_unlocked. We have many newline characters that need to be emitted,
// but stdio needs to do extra checks to handle line buffering mode. These
// extra checks make putchar_unlocked fall off its inlined code path, hitting
// slow system code. In practice, using 'write' directly makes 'clang -E -P'
// about 10% faster than using the stdio path on darwin.
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#else
#define USE_STDIO 1
#endif
static char *OutBufStart = 0, *OutBufEnd, *OutBufCur;
/// InitOutputBuffer - Initialize our output buffer.
///
static void InitOutputBuffer() {
#ifndef USE_STDIO
OutBufStart = new char[64*1024];
OutBufEnd = OutBufStart+64*1024;
OutBufCur = OutBufStart;
#endif
}
/// FlushBuffer - Write the accumulated bytes to the output stream.
///
static void FlushBuffer() {
#ifndef USE_STDIO
write(STDOUT_FILENO, OutBufStart, OutBufCur-OutBufStart);
OutBufCur = OutBufStart;
#endif
}
/// CleanupOutputBuffer - Finish up output.
///
static void CleanupOutputBuffer() {
#ifndef USE_STDIO
FlushBuffer();
delete [] OutBufStart;
#endif
}
static void OutputChar(char c) {
#if defined(_MSC_VER)
putchar(c);
#elif defined(USE_STDIO)
putchar_unlocked(c);
#else
if (OutBufCur >= OutBufEnd)
FlushBuffer();
*OutBufCur++ = c;
#endif
}
static void OutputString(const char *Ptr, unsigned Size) {
#ifdef USE_STDIO
fwrite(Ptr, Size, 1, stdout);
#else
if (OutBufCur+Size >= OutBufEnd)
FlushBuffer();
switch (Size) {
default:
memcpy(OutBufCur, Ptr, Size);
break;
case 3:
OutBufCur[2] = Ptr[2];
case 2:
OutBufCur[1] = Ptr[1];
case 1:
OutBufCur[0] = Ptr[0];
case 0:
break;
}
OutBufCur += Size;
#endif
}
//===----------------------------------------------------------------------===//
// Preprocessed token printer
//===----------------------------------------------------------------------===//
static llvm::cl::opt<bool>
DisableLineMarkers("P", llvm::cl::desc("Disable linemarker output in -E mode"));
static llvm::cl::opt<bool>
EnableCommentOutput("C", llvm::cl::desc("Enable comment output in -E mode"));
static llvm::cl::opt<bool>
EnableMacroCommentOutput("CC",
llvm::cl::desc("Enable comment output in -E mode, "
"even from macro expansions"));
namespace {
class PrintPPOutputPPCallbacks : public PPCallbacks {
Preprocessor &PP;
unsigned CurLine;
bool EmittedTokensOnThisLine;
DirectoryLookup::DirType FileType;
llvm::SmallString<512> CurFilename;
public:
PrintPPOutputPPCallbacks(Preprocessor &pp) : PP(pp) {
CurLine = 0;
CurFilename += "<uninit>";
EmittedTokensOnThisLine = false;
FileType = DirectoryLookup::NormalHeaderDir;
}
void SetEmittedTokensOnThisLine() { EmittedTokensOnThisLine = true; }
bool hasEmittedTokensOnThisLine() const { return EmittedTokensOnThisLine; }
virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
DirectoryLookup::DirType FileType);
virtual void Ident(SourceLocation Loc, const std::string &str);
bool HandleFirstTokOnLine(Token &Tok);
bool MoveToLine(SourceLocation Loc);
bool AvoidConcat(const Token &PrevTok, const Token &Tok);
};
}
/// UToStr - Do itoa on the specified number, in-place in the specified buffer.
/// endptr points to the end of the buffer.
static char *UToStr(unsigned N, char *EndPtr) {
// Null terminate the buffer.
*--EndPtr = '\0';
if (N == 0) // Zero is a special case.
*--EndPtr = '0';
while (N) {
*--EndPtr = '0' + char(N % 10);
N /= 10;
}
return EndPtr;
}
/// MoveToLine - Move the output to the source line specified by the location
/// object. We can do this by emitting some number of \n's, or be emitting a
/// #line directive. This returns false if already at the specified line, true
/// if some newlines were emitted.
bool PrintPPOutputPPCallbacks::MoveToLine(SourceLocation Loc) {
if (DisableLineMarkers) {
unsigned LineNo = PP.getSourceManager().getLogicalLineNumber(Loc);
if (LineNo == CurLine) return false;
CurLine = LineNo;
if (!EmittedTokensOnThisLine)
return true;
OutputChar('\n');
EmittedTokensOnThisLine = false;
return true;
}
unsigned LineNo = PP.getSourceManager().getLogicalLineNumber(Loc);
// If this line is "close enough" to the original line, just print newlines,
// otherwise print a #line directive.
if (LineNo-CurLine < 8) {
if (LineNo-CurLine == 1)
OutputChar('\n');
else if (LineNo == CurLine)
return false; // Phys line moved, but logical line didn't.
else {
const char *NewLines = "\n\n\n\n\n\n\n\n";
OutputString(NewLines, LineNo-CurLine);
}
CurLine = LineNo;
} else {
if (EmittedTokensOnThisLine) {
OutputChar('\n');
EmittedTokensOnThisLine = false;
}
CurLine = LineNo;
OutputChar('#');
OutputChar(' ');
char NumberBuffer[20];
const char *NumStr = UToStr(LineNo, NumberBuffer+20);
OutputString(NumStr, (NumberBuffer+20)-NumStr-1);
OutputChar(' ');
OutputChar('"');
OutputString(&CurFilename[0], CurFilename.size());
OutputChar('"');
if (FileType == DirectoryLookup::SystemHeaderDir)
OutputString(" 3", 2);
else if (FileType == DirectoryLookup::ExternCSystemHeaderDir)
OutputString(" 3 4", 4);
OutputChar('\n');
}
return true;
}
/// FileChanged - Whenever the preprocessor enters or exits a #include file
/// it invokes this handler. Update our conception of the current source
/// position.
void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
FileChangeReason Reason,
DirectoryLookup::DirType FileType) {
// Unless we are exiting a #include, make sure to skip ahead to the line the
// #include directive was at.
SourceManager &SourceMgr = PP.getSourceManager();
if (Reason == PPCallbacks::EnterFile) {
MoveToLine(SourceMgr.getIncludeLoc(Loc));
} else if (Reason == PPCallbacks::SystemHeaderPragma) {
MoveToLine(Loc);
// TODO GCC emits the # directive for this directive on the line AFTER the
// directive and emits a bunch of spaces that aren't needed. Emulate this
// strange behavior.
}
Loc = SourceMgr.getLogicalLoc(Loc);
CurLine = SourceMgr.getLineNumber(Loc);
if (DisableLineMarkers) return;
CurFilename.clear();
CurFilename += SourceMgr.getSourceName(Loc);
Lexer::Stringify(CurFilename);
FileType = FileType;
if (EmittedTokensOnThisLine) {
OutputChar('\n');
EmittedTokensOnThisLine = false;
}
OutputChar('#');
OutputChar(' ');
char NumberBuffer[20];
const char *NumStr = UToStr(CurLine, NumberBuffer+20);
OutputString(NumStr, (NumberBuffer+20)-NumStr-1);
OutputChar(' ');
OutputChar('"');
OutputString(&CurFilename[0], CurFilename.size());
OutputChar('"');
switch (Reason) {
case PPCallbacks::EnterFile:
OutputString(" 1", 2);
break;
case PPCallbacks::ExitFile:
OutputString(" 2", 2);
break;
case PPCallbacks::SystemHeaderPragma: break;
case PPCallbacks::RenameFile: break;
}
if (FileType == DirectoryLookup::SystemHeaderDir)
OutputString(" 3", 2);
else if (FileType == DirectoryLookup::ExternCSystemHeaderDir)
OutputString(" 3 4", 4);
OutputChar('\n');
}
/// HandleIdent - Handle #ident directives when read by the preprocessor.
///
void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
MoveToLine(Loc);
OutputString("#ident ", strlen("#ident "));
OutputString(&S[0], S.size());
EmittedTokensOnThisLine = true;
}
/// HandleFirstTokOnLine - When emitting a preprocessed file in -E mode, this
/// is called for the first token on each new line. If this really is the start
/// of a new logical line, handle it and return true, otherwise return false.
/// This may not be the start of a logical line because the "start of line"
/// marker is set for physical lines, not logical ones.
bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
// Figure out what line we went to and insert the appropriate number of
// newline characters.
if (!MoveToLine(Tok.getLocation()))
return false;
// Print out space characters so that the first token on a line is
// indented for easy reading.
const SourceManager &SourceMgr = PP.getSourceManager();
unsigned ColNo = SourceMgr.getLogicalColumnNumber(Tok.getLocation());
// This hack prevents stuff like:
// #define HASH #
// HASH define foo bar
// From having the # character end up at column 1, which makes it so it
// is not handled as a #define next time through the preprocessor if in
// -fpreprocessed mode.
if (ColNo <= 1 && Tok.is(tok::hash))
OutputChar(' ');
// Otherwise, indent the appropriate number of spaces.
for (; ColNo > 1; --ColNo)
OutputChar(' ');
return true;
}
namespace {
struct UnknownPragmaHandler : public PragmaHandler {
const char *Prefix;
PrintPPOutputPPCallbacks *Callbacks;
UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
: PragmaHandler(0), Prefix(prefix), Callbacks(callbacks) {}
virtual void HandlePragma(Preprocessor &PP, Token &PragmaTok) {
// Figure out what line we went to and insert the appropriate number of
// newline characters.
Callbacks->MoveToLine(PragmaTok.getLocation());
OutputString(Prefix, strlen(Prefix));
// Read and print all of the pragma tokens.
while (PragmaTok.isNot(tok::eom)) {
if (PragmaTok.hasLeadingSpace())
OutputChar(' ');
std::string TokSpell = PP.getSpelling(PragmaTok);
OutputString(&TokSpell[0], TokSpell.size());
PP.LexUnexpandedToken(PragmaTok);
}
OutputChar('\n');
}
};
} // end anonymous namespace
enum AvoidConcatInfo {
/// By default, a token never needs to avoid concatenation. Most tokens (e.g.
/// ',', ')', etc) don't cause a problem when concatenated.
aci_never_avoid_concat = 0,
/// aci_custom_firstchar - AvoidConcat contains custom code to handle this
/// token's requirements, and it needs to know the first character of the
/// token.
aci_custom_firstchar = 1,
/// aci_custom - AvoidConcat contains custom code to handle this token's
/// requirements, but it doesn't need to know the first character of the
/// token.
aci_custom = 2,
/// aci_avoid_equal - Many tokens cannot be safely followed by an '='
/// character. For example, "<<" turns into "<<=" when followed by an =.
aci_avoid_equal = 4
};
/// This array contains information for each token on what action to take when
/// avoiding concatenation of tokens in the AvoidConcat method.
static char TokenInfo[tok::NUM_TOKENS];
/// InitAvoidConcatTokenInfo - Tokens that must avoid concatenation should be
/// marked by this function.
static void InitAvoidConcatTokenInfo() {
// These tokens have custom code in AvoidConcat.
TokenInfo[tok::identifier ] |= aci_custom;
TokenInfo[tok::numeric_constant] |= aci_custom_firstchar;
TokenInfo[tok::period ] |= aci_custom_firstchar;
TokenInfo[tok::amp ] |= aci_custom_firstchar;
TokenInfo[tok::plus ] |= aci_custom_firstchar;
TokenInfo[tok::minus ] |= aci_custom_firstchar;
TokenInfo[tok::slash ] |= aci_custom_firstchar;
TokenInfo[tok::less ] |= aci_custom_firstchar;
TokenInfo[tok::greater ] |= aci_custom_firstchar;
TokenInfo[tok::pipe ] |= aci_custom_firstchar;
TokenInfo[tok::percent ] |= aci_custom_firstchar;
TokenInfo[tok::colon ] |= aci_custom_firstchar;
TokenInfo[tok::hash ] |= aci_custom_firstchar;
TokenInfo[tok::arrow ] |= aci_custom_firstchar;
// These tokens change behavior if followed by an '='.
TokenInfo[tok::amp ] |= aci_avoid_equal; // &=
TokenInfo[tok::plus ] |= aci_avoid_equal; // +=
TokenInfo[tok::minus ] |= aci_avoid_equal; // -=
TokenInfo[tok::slash ] |= aci_avoid_equal; // /=
TokenInfo[tok::less ] |= aci_avoid_equal; // <=
TokenInfo[tok::greater ] |= aci_avoid_equal; // >=
TokenInfo[tok::pipe ] |= aci_avoid_equal; // |=
TokenInfo[tok::percent ] |= aci_avoid_equal; // %=
TokenInfo[tok::star ] |= aci_avoid_equal; // *=
TokenInfo[tok::exclaim ] |= aci_avoid_equal; // !=
TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<=
TokenInfo[tok::greaterequal] |= aci_avoid_equal; // >>=
TokenInfo[tok::caret ] |= aci_avoid_equal; // ^=
TokenInfo[tok::equal ] |= aci_avoid_equal; // ==
}
/// AvoidConcat - If printing PrevTok immediately followed by Tok would cause
/// the two individual tokens to be lexed as a single token, return true (which
/// causes a space to be printed between them). This allows the output of -E
/// mode to be lexed to the same token stream as lexing the input directly
/// would.
///
/// This code must conservatively return true if it doesn't want to be 100%
/// accurate. This will cause the output to include extra space characters, but
/// the resulting output won't have incorrect concatenations going on. Examples
/// include "..", which we print with a space between, because we don't want to
/// track enough to tell "x.." from "...".
bool PrintPPOutputPPCallbacks::AvoidConcat(const Token &PrevTok,
const Token &Tok) {
char Buffer[256];
tok::TokenKind PrevKind = PrevTok.getKind();
if (PrevTok.getIdentifierInfo()) // Language keyword or named operator.
PrevKind = tok::identifier;
// Look up information on when we should avoid concatenation with prevtok.
unsigned ConcatInfo = TokenInfo[PrevKind];
// If prevtok never causes a problem for anything after it, return quickly.
if (ConcatInfo == 0) return false;
if (ConcatInfo & aci_avoid_equal) {
// If the next token is '=' or '==', avoid concatenation.
if (Tok.is(tok::equal) || Tok.is(tok::equalequal))
return true;
ConcatInfo &= ~aci_avoid_equal;
}
if (ConcatInfo == 0) return false;
// Basic algorithm: we look at the first character of the second token, and
// determine whether it, if appended to the first token, would form (or would
// contribute) to a larger token if concatenated.
char FirstChar = 0;
if (ConcatInfo & aci_custom) {
// If the token does not need to know the first character, don't get it.
} else if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
// Avoid spelling identifiers, the most common form of token.
FirstChar = II->getName()[0];
} else if (!Tok.needsCleaning()) {
SourceManager &SrcMgr = PP.getSourceManager();
FirstChar =
*SrcMgr.getCharacterData(SrcMgr.getPhysicalLoc(Tok.getLocation()));
} else if (Tok.getLength() < 256) {
const char *TokPtr = Buffer;
PP.getSpelling(Tok, TokPtr);
FirstChar = TokPtr[0];
} else {
FirstChar = PP.getSpelling(Tok)[0];
}
switch (PrevKind) {
default: assert(0 && "InitAvoidConcatTokenInfo built wrong");
case tok::identifier: // id+id or id+number or id+L"foo".
if (Tok.is(tok::numeric_constant) || Tok.getIdentifierInfo() ||
Tok.is(tok::wide_string_literal) /* ||
Tok.is(tok::wide_char_literal)*/)
return true;
if (Tok.isNot(tok::char_constant))
return false;
// FIXME: need a wide_char_constant!
if (!Tok.needsCleaning()) {
SourceManager &SrcMgr = PP.getSourceManager();
return *SrcMgr.getCharacterData(SrcMgr.getPhysicalLoc(Tok.getLocation()))
== 'L';
} else if (Tok.getLength() < 256) {
const char *TokPtr = Buffer;
PP.getSpelling(Tok, TokPtr);
return TokPtr[0] == 'L';
} else {
return PP.getSpelling(Tok)[0] == 'L';
}
case tok::numeric_constant:
return isalnum(FirstChar) || Tok.is(tok::numeric_constant) ||
FirstChar == '+' || FirstChar == '-' || FirstChar == '.';
case tok::period: // ..., .*, .1234
return FirstChar == '.' || FirstChar == '*' || isdigit(FirstChar);
case tok::amp: // &&
return FirstChar == '&';
case tok::plus: // ++
return FirstChar == '+';
case tok::minus: // --, ->, ->*
return FirstChar == '-' || FirstChar == '>';
case tok::slash: //, /*, //
return FirstChar == '*' || FirstChar == '/';
case tok::less: // <<, <<=, <:, <%
return FirstChar == '<' || FirstChar == ':' || FirstChar == '%';
case tok::greater: // >>, >>=
return FirstChar == '>';
case tok::pipe: // ||
return FirstChar == '|';
case tok::percent: // %>, %:
return FirstChar == '>' || FirstChar == ':';
case tok::colon: // ::, :>
return FirstChar == ':' || FirstChar == '>';
case tok::hash: // ##, #@, %:%:
return FirstChar == '#' || FirstChar == '@' || FirstChar == '%';
case tok::arrow: // ->*
return FirstChar == '*';
}
}
/// DoPrintPreprocessedInput - This implements -E mode.
///
void clang::DoPrintPreprocessedInput(Preprocessor &PP) {
// Inform the preprocessor whether we want it to retain comments or not, due
// to -C or -CC.
PP.SetCommentRetentionState(EnableCommentOutput, EnableMacroCommentOutput);
InitOutputBuffer();
InitAvoidConcatTokenInfo();
Token Tok, PrevTok;
char Buffer[256];
PrintPPOutputPPCallbacks *Callbacks = new PrintPPOutputPPCallbacks(PP);
PP.setPPCallbacks(Callbacks);
PP.AddPragmaHandler(0, new UnknownPragmaHandler("#pragma", Callbacks));
PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
// After we have configured the preprocessor, enter the main file.
// Start parsing the specified input file.
PP.EnterMainSourceFile();
// Consume all of the tokens that come from the predefines buffer. Those
// should not be emitted into the output and are guaranteed to be at the
// start.
const SourceManager &SourceMgr = PP.getSourceManager();
do PP.Lex(Tok);
while (Tok.isNot(tok::eof) && Tok.getLocation().isFileID() &&
!strcmp(SourceMgr.getSourceName(Tok.getLocation()), "<predefines>"));
while (1) {
// If this token is at the start of a line, emit newlines if needed.
if (Tok.isAtStartOfLine() && Callbacks->HandleFirstTokOnLine(Tok)) {
// done.
} else if (Tok.hasLeadingSpace() ||
// If we haven't emitted a token on this line yet, PrevTok isn't
// useful to look at and no concatenation could happen anyway.
(Callbacks->hasEmittedTokensOnThisLine() &&
// Don't print "-" next to "-", it would form "--".
Callbacks->AvoidConcat(PrevTok, Tok))) {
OutputChar(' ');
}
if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
const char *Str = II->getName();
unsigned Len = Tok.needsCleaning() ? strlen(Str) : Tok.getLength();
OutputString(Str, Len);
} else if (Tok.getLength() < 256) {
const char *TokPtr = Buffer;
unsigned Len = PP.getSpelling(Tok, TokPtr);
OutputString(TokPtr, Len);
} else {
std::string S = PP.getSpelling(Tok);
OutputString(&S[0], S.size());
}
Callbacks->SetEmittedTokensOnThisLine();
if (Tok.is(tok::eof)) break;
PrevTok = Tok;
PP.Lex(Tok);
}
OutputChar('\n');
CleanupOutputBuffer();
}
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