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llvm-project/clang/lib/Lex/Preprocessor.cpp

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//===--- Preprocess.cpp - C Language Family Preprocessor Implementation ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Preprocessor interface.
//
//===----------------------------------------------------------------------===//
//
// Options to support:
// -H - Print the name of each header file used.
// -d[DNI] - Dump various things.
// -fworking-directory - #line's with preprocessor's working dir.
// -fpreprocessed
// -dependency-file,-M,-MM,-MF,-MG,-MP,-MT,-MQ,-MD,-MMD
// -W*
// -w
//
// Messages to emit:
// "Multiple include guards may be useful for:\n"
//
//===----------------------------------------------------------------------===//
#include "clang/Lex/Preprocessor.h"
#include "MacroArgs.h"
#include "clang/Lex/ExternalPreprocessorSource.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Pragma.h"
#include "clang/Lex/PreprocessingRecord.h"
#include "clang/Lex/ScratchBuffer.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
//===----------------------------------------------------------------------===//
ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
Preprocessor::Preprocessor(Diagnostic &diags, const LangOptions &opts,
const TargetInfo &target, SourceManager &SM,
HeaderSearch &Headers,
IdentifierInfoLookup* IILookup,
bool OwnsHeaders)
: Diags(&diags), Features(opts), Target(target),FileMgr(Headers.getFileMgr()),
SourceMgr(SM), HeaderInfo(Headers), ExternalSource(0),
Identifiers(opts, IILookup), BuiltinInfo(Target), CodeCompletionFile(0),
SkipMainFilePreamble(0, true), CurPPLexer(0), CurDirLookup(0), Callbacks(0),
MacroArgCache(0), Record(0) {
ScratchBuf = new ScratchBuffer(SourceMgr);
CounterValue = 0; // __COUNTER__ starts at 0.
OwnsHeaderSearch = OwnsHeaders;
// Clear stats.
NumDirectives = NumDefined = NumUndefined = NumPragma = 0;
NumIf = NumElse = NumEndif = 0;
NumEnteredSourceFiles = 0;
NumMacroExpanded = NumFnMacroExpanded = NumBuiltinMacroExpanded = 0;
NumFastMacroExpanded = NumTokenPaste = NumFastTokenPaste = 0;
MaxIncludeStackDepth = 0;
NumSkipped = 0;
// Default to discarding comments.
KeepComments = false;
KeepMacroComments = false;
// Macro expansion is enabled.
DisableMacroExpansion = false;
InMacroArgs = false;
NumCachedTokenLexers = 0;
CachedLexPos = 0;
// We haven't read anything from the external source.
ReadMacrosFromExternalSource = false;
// "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
// This gets unpoisoned where it is allowed.
(Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
// Initialize the pragma handlers.
PragmaHandlers = new PragmaNamespace(llvm::StringRef());
RegisterBuiltinPragmas();
// Initialize builtin macros like __LINE__ and friends.
RegisterBuiltinMacros();
}
Preprocessor::~Preprocessor() {
assert(BacktrackPositions.empty() && "EnableBacktrack/Backtrack imbalance!");
while (!IncludeMacroStack.empty()) {
delete IncludeMacroStack.back().TheLexer;
delete IncludeMacroStack.back().TheTokenLexer;
IncludeMacroStack.pop_back();
}
// Free any macro definitions.
for (llvm::DenseMap<IdentifierInfo*, MacroInfo*>::iterator I =
Macros.begin(), E = Macros.end(); I != E; ++I) {
// We don't need to free the MacroInfo objects directly. These
// will be released when the BumpPtrAllocator 'BP' object gets
// destroyed. We still need to run the dtor, however, to free
// memory alocated by MacroInfo.
I->second->Destroy();
I->first->setHasMacroDefinition(false);
}
for (std::vector<MacroInfo*>::iterator I = MICache.begin(),
E = MICache.end(); I != E; ++I) {
// We don't need to free the MacroInfo objects directly. These
// will be released when the BumpPtrAllocator 'BP' object gets
// destroyed. We still need to run the dtor, however, to free
// memory alocated by MacroInfo.
(*I)->Destroy();
}
// Free any cached macro expanders.
for (unsigned i = 0, e = NumCachedTokenLexers; i != e; ++i)
delete TokenLexerCache[i];
// Free any cached MacroArgs.
for (MacroArgs *ArgList = MacroArgCache; ArgList; )
ArgList = ArgList->deallocate();
// Release pragma information.
delete PragmaHandlers;
// Delete the scratch buffer info.
delete ScratchBuf;
// Delete the header search info, if we own it.
if (OwnsHeaderSearch)
delete &HeaderInfo;
delete Callbacks;
}
void Preprocessor::setPTHManager(PTHManager* pm) {
PTH.reset(pm);
FileMgr.addStatCache(PTH->createStatCache());
}
void Preprocessor::DumpToken(const Token &Tok, bool DumpFlags) const {
llvm::errs() << tok::getTokenName(Tok.getKind()) << " '"
<< getSpelling(Tok) << "'";
if (!DumpFlags) return;
llvm::errs() << "\t";
if (Tok.isAtStartOfLine())
llvm::errs() << " [StartOfLine]";
if (Tok.hasLeadingSpace())
llvm::errs() << " [LeadingSpace]";
if (Tok.isExpandDisabled())
llvm::errs() << " [ExpandDisabled]";
if (Tok.needsCleaning()) {
const char *Start = SourceMgr.getCharacterData(Tok.getLocation());
llvm::errs() << " [UnClean='" << llvm::StringRef(Start, Tok.getLength())
<< "']";
}
llvm::errs() << "\tLoc=<";
DumpLocation(Tok.getLocation());
llvm::errs() << ">";
}
void Preprocessor::DumpLocation(SourceLocation Loc) const {
Loc.dump(SourceMgr);
}
void Preprocessor::DumpMacro(const MacroInfo &MI) const {
llvm::errs() << "MACRO: ";
for (unsigned i = 0, e = MI.getNumTokens(); i != e; ++i) {
DumpToken(MI.getReplacementToken(i));
llvm::errs() << " ";
}
llvm::errs() << "\n";
}
void Preprocessor::PrintStats() {
llvm::errs() << "\n*** Preprocessor Stats:\n";
llvm::errs() << NumDirectives << " directives found:\n";
llvm::errs() << " " << NumDefined << " #define.\n";
llvm::errs() << " " << NumUndefined << " #undef.\n";
llvm::errs() << " #include/#include_next/#import:\n";
llvm::errs() << " " << NumEnteredSourceFiles << " source files entered.\n";
llvm::errs() << " " << MaxIncludeStackDepth << " max include stack depth\n";
llvm::errs() << " " << NumIf << " #if/#ifndef/#ifdef.\n";
llvm::errs() << " " << NumElse << " #else/#elif.\n";
llvm::errs() << " " << NumEndif << " #endif.\n";
llvm::errs() << " " << NumPragma << " #pragma.\n";
llvm::errs() << NumSkipped << " #if/#ifndef#ifdef regions skipped\n";
llvm::errs() << NumMacroExpanded << "/" << NumFnMacroExpanded << "/"
<< NumBuiltinMacroExpanded << " obj/fn/builtin macros expanded, "
<< NumFastMacroExpanded << " on the fast path.\n";
llvm::errs() << (NumFastTokenPaste+NumTokenPaste)
<< " token paste (##) operations performed, "
<< NumFastTokenPaste << " on the fast path.\n";
}
Preprocessor::macro_iterator
Preprocessor::macro_begin(bool IncludeExternalMacros) const {
if (IncludeExternalMacros && ExternalSource &&
!ReadMacrosFromExternalSource) {
ReadMacrosFromExternalSource = true;
ExternalSource->ReadDefinedMacros();
}
return Macros.begin();
}
Preprocessor::macro_iterator
Preprocessor::macro_end(bool IncludeExternalMacros) const {
if (IncludeExternalMacros && ExternalSource &&
!ReadMacrosFromExternalSource) {
ReadMacrosFromExternalSource = true;
ExternalSource->ReadDefinedMacros();
}
return Macros.end();
}
bool Preprocessor::SetCodeCompletionPoint(const FileEntry *File,
unsigned TruncateAtLine,
unsigned TruncateAtColumn) {
using llvm::MemoryBuffer;
CodeCompletionFile = File;
// Okay to clear out the code-completion point by passing NULL.
if (!CodeCompletionFile)
return false;
// Load the actual file's contents.
bool Invalid = false;
const MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File, &Invalid);
if (Invalid)
return true;
// Find the byte position of the truncation point.
const char *Position = Buffer->getBufferStart();
for (unsigned Line = 1; Line < TruncateAtLine; ++Line) {
for (; *Position; ++Position) {
if (*Position != '\r' && *Position != '\n')
continue;
// Eat \r\n or \n\r as a single line.
if ((Position[1] == '\r' || Position[1] == '\n') &&
Position[0] != Position[1])
++Position;
++Position;
break;
}
}
Position += TruncateAtColumn - 1;
// Truncate the buffer.
if (Position < Buffer->getBufferEnd()) {
llvm::StringRef Data(Buffer->getBufferStart(),
Position-Buffer->getBufferStart());
MemoryBuffer *TruncatedBuffer
= MemoryBuffer::getMemBufferCopy(Data, Buffer->getBufferIdentifier());
SourceMgr.overrideFileContents(File, TruncatedBuffer);
}
return false;
}
bool Preprocessor::isCodeCompletionFile(SourceLocation FileLoc) const {
return CodeCompletionFile && FileLoc.isFileID() &&
SourceMgr.getFileEntryForID(SourceMgr.getFileID(FileLoc))
== CodeCompletionFile;
}
//===----------------------------------------------------------------------===//
// Token Spelling
//===----------------------------------------------------------------------===//
/// getSpelling() - Return the 'spelling' of this token. The spelling of a
/// token are the characters used to represent the token in the source file
/// after trigraph expansion and escaped-newline folding. In particular, this
/// wants to get the true, uncanonicalized, spelling of things like digraphs
/// UCNs, etc.
std::string Preprocessor::getSpelling(const Token &Tok,
const SourceManager &SourceMgr,
const LangOptions &Features,
bool *Invalid) {
assert((int)Tok.getLength() >= 0 && "Token character range is bogus!");
// If this token contains nothing interesting, return it directly.
bool CharDataInvalid = false;
const char* TokStart = SourceMgr.getCharacterData(Tok.getLocation(),
&CharDataInvalid);
if (Invalid)
*Invalid = CharDataInvalid;
if (CharDataInvalid)
return std::string();
if (!Tok.needsCleaning())
return std::string(TokStart, TokStart+Tok.getLength());
std::string Result;
Result.reserve(Tok.getLength());
// Otherwise, hard case, relex the characters into the string.
for (const char *Ptr = TokStart, *End = TokStart+Tok.getLength();
Ptr != End; ) {
unsigned CharSize;
Result.push_back(Lexer::getCharAndSizeNoWarn(Ptr, CharSize, Features));
Ptr += CharSize;
}
assert(Result.size() != unsigned(Tok.getLength()) &&
"NeedsCleaning flag set on something that didn't need cleaning!");
return Result;
}
/// getSpelling() - Return the 'spelling' of this token. The spelling of a
/// token are the characters used to represent the token in the source file
/// after trigraph expansion and escaped-newline folding. In particular, this
/// wants to get the true, uncanonicalized, spelling of things like digraphs
/// UCNs, etc.
std::string Preprocessor::getSpelling(const Token &Tok, bool *Invalid) const {
return getSpelling(Tok, SourceMgr, Features, Invalid);
}
/// getSpelling - This method is used to get the spelling of a token into a
/// preallocated buffer, instead of as an std::string. The caller is required
/// to allocate enough space for the token, which is guaranteed to be at least
/// Tok.getLength() bytes long. The actual length of the token is returned.
///
/// Note that this method may do two possible things: it may either fill in
/// the buffer specified with characters, or it may *change the input pointer*
/// to point to a constant buffer with the data already in it (avoiding a
/// copy). The caller is not allowed to modify the returned buffer pointer
/// if an internal buffer is returned.
unsigned Preprocessor::getSpelling(const Token &Tok,
const char *&Buffer, bool *Invalid) const {
assert((int)Tok.getLength() >= 0 && "Token character range is bogus!");
// If this token is an identifier, just return the string from the identifier
// table, which is very quick.
if (const IdentifierInfo *II = Tok.getIdentifierInfo()) {
Buffer = II->getNameStart();
return II->getLength();
}
// Otherwise, compute the start of the token in the input lexer buffer.
const char *TokStart = 0;
if (Tok.isLiteral())
TokStart = Tok.getLiteralData();
if (TokStart == 0) {
bool CharDataInvalid = false;
TokStart = SourceMgr.getCharacterData(Tok.getLocation(), &CharDataInvalid);
if (Invalid)
*Invalid = CharDataInvalid;
if (CharDataInvalid) {
Buffer = "";
return 0;
}
}
// If this token contains nothing interesting, return it directly.
if (!Tok.needsCleaning()) {
Buffer = TokStart;
return Tok.getLength();
}
// Otherwise, hard case, relex the characters into the string.
char *OutBuf = const_cast<char*>(Buffer);
for (const char *Ptr = TokStart, *End = TokStart+Tok.getLength();
Ptr != End; ) {
unsigned CharSize;
*OutBuf++ = Lexer::getCharAndSizeNoWarn(Ptr, CharSize, Features);
Ptr += CharSize;
}
assert(unsigned(OutBuf-Buffer) != Tok.getLength() &&
"NeedsCleaning flag set on something that didn't need cleaning!");
return OutBuf-Buffer;
}
/// getSpelling - This method is used to get the spelling of a token into a
/// SmallVector. Note that the returned StringRef may not point to the
/// supplied buffer if a copy can be avoided.
llvm::StringRef Preprocessor::getSpelling(const Token &Tok,
llvm::SmallVectorImpl<char> &Buffer,
bool *Invalid) const {
// Try the fast path.
if (const IdentifierInfo *II = Tok.getIdentifierInfo())
return II->getName();
// Resize the buffer if we need to copy into it.
if (Tok.needsCleaning())
Buffer.resize(Tok.getLength());
const char *Ptr = Buffer.data();
unsigned Len = getSpelling(Tok, Ptr, Invalid);
return llvm::StringRef(Ptr, Len);
}
/// CreateString - Plop the specified string into a scratch buffer and return a
/// location for it. If specified, the source location provides a source
/// location for the token.
void Preprocessor::CreateString(const char *Buf, unsigned Len, Token &Tok,
SourceLocation InstantiationLoc) {
Tok.setLength(Len);
const char *DestPtr;
SourceLocation Loc = ScratchBuf->getToken(Buf, Len, DestPtr);
if (InstantiationLoc.isValid())
Loc = SourceMgr.createInstantiationLoc(Loc, InstantiationLoc,
InstantiationLoc, Len);
Tok.setLocation(Loc);
// If this is a literal token, set the pointer data.
if (Tok.isLiteral())
Tok.setLiteralData(DestPtr);
}
/// AdvanceToTokenCharacter - Given a location that specifies the start of a
/// token, return a new location that specifies a character within the token.
SourceLocation Preprocessor::AdvanceToTokenCharacter(SourceLocation TokStart,
unsigned CharNo) {
// Figure out how many physical characters away the specified instantiation
// character is. This needs to take into consideration newlines and
// trigraphs.
bool Invalid = false;
const char *TokPtr = SourceMgr.getCharacterData(TokStart, &Invalid);
// If they request the first char of the token, we're trivially done.
if (Invalid || (CharNo == 0 && Lexer::isObviouslySimpleCharacter(*TokPtr)))
return TokStart;
unsigned PhysOffset = 0;
// The usual case is that tokens don't contain anything interesting. Skip
// over the uninteresting characters. If a token only consists of simple
// chars, this method is extremely fast.
while (Lexer::isObviouslySimpleCharacter(*TokPtr)) {
if (CharNo == 0)
return TokStart.getFileLocWithOffset(PhysOffset);
++TokPtr, --CharNo, ++PhysOffset;
}
// If we have a character that may be a trigraph or escaped newline, use a
// lexer to parse it correctly.
for (; CharNo; --CharNo) {
unsigned Size;
Lexer::getCharAndSizeNoWarn(TokPtr, Size, Features);
TokPtr += Size;
PhysOffset += Size;
}
// Final detail: if we end up on an escaped newline, we want to return the
// location of the actual byte of the token. For example foo\<newline>bar
// advanced by 3 should return the location of b, not of \\. One compounding
// detail of this is that the escape may be made by a trigraph.
if (!Lexer::isObviouslySimpleCharacter(*TokPtr))
PhysOffset += Lexer::SkipEscapedNewLines(TokPtr)-TokPtr;
return TokStart.getFileLocWithOffset(PhysOffset);
}
SourceLocation Preprocessor::getLocForEndOfToken(SourceLocation Loc,
unsigned Offset) {
if (Loc.isInvalid() || !Loc.isFileID())
return SourceLocation();
unsigned Len = Lexer::MeasureTokenLength(Loc, getSourceManager(), Features);
if (Len > Offset)
Len = Len - Offset;
else
return Loc;
return AdvanceToTokenCharacter(Loc, Len);
}
//===----------------------------------------------------------------------===//
// Preprocessor Initialization Methods
//===----------------------------------------------------------------------===//
/// EnterMainSourceFile - Enter the specified FileID as the main source file,
/// which implicitly adds the builtin defines etc.
void Preprocessor::EnterMainSourceFile() {
// We do not allow the preprocessor to reenter the main file. Doing so will
// cause FileID's to accumulate information from both runs (e.g. #line
// information) and predefined macros aren't guaranteed to be set properly.
assert(NumEnteredSourceFiles == 0 && "Cannot reenter the main file!");
FileID MainFileID = SourceMgr.getMainFileID();
// Enter the main file source buffer.
EnterSourceFile(MainFileID, 0, SourceLocation());
// If we've been asked to skip bytes in the main file (e.g., as part of a
// precompiled preamble), do so now.
if (SkipMainFilePreamble.first > 0)
CurLexer->SkipBytes(SkipMainFilePreamble.first,
SkipMainFilePreamble.second);
// Tell the header info that the main file was entered. If the file is later
// #imported, it won't be re-entered.
if (const FileEntry *FE = SourceMgr.getFileEntryForID(MainFileID))
HeaderInfo.IncrementIncludeCount(FE);
// Preprocess Predefines to populate the initial preprocessor state.
llvm::MemoryBuffer *SB =
llvm::MemoryBuffer::getMemBufferCopy(Predefines, "<built-in>");
assert(SB && "Cannot fail to create predefined source buffer");
FileID FID = SourceMgr.createFileIDForMemBuffer(SB);
assert(!FID.isInvalid() && "Could not create FileID for predefines?");
// Start parsing the predefines.
EnterSourceFile(FID, 0, SourceLocation());
}
void Preprocessor::EndSourceFile() {
// Notify the client that we reached the end of the source file.
if (Callbacks)
Callbacks->EndOfMainFile();
}
//===----------------------------------------------------------------------===//
// Lexer Event Handling.
//===----------------------------------------------------------------------===//
/// LookUpIdentifierInfo - Given a tok::identifier token, look up the
/// identifier information for the token and install it into the token.
IdentifierInfo *Preprocessor::LookUpIdentifierInfo(Token &Identifier,
const char *BufPtr) const {
assert(Identifier.is(tok::identifier) && "Not an identifier!");
assert(Identifier.getIdentifierInfo() == 0 && "Identinfo already exists!");
// Look up this token, see if it is a macro, or if it is a language keyword.
IdentifierInfo *II;
if (BufPtr && !Identifier.needsCleaning()) {
// No cleaning needed, just use the characters from the lexed buffer.
II = getIdentifierInfo(llvm::StringRef(BufPtr, Identifier.getLength()));
} else {
// Cleaning needed, alloca a buffer, clean into it, then use the buffer.
llvm::SmallString<64> IdentifierBuffer;
llvm::StringRef CleanedStr = getSpelling(Identifier, IdentifierBuffer);
II = getIdentifierInfo(CleanedStr);
}
Identifier.setIdentifierInfo(II);
return II;
}
/// HandleIdentifier - This callback is invoked when the lexer reads an
/// identifier. This callback looks up the identifier in the map and/or
/// potentially macro expands it or turns it into a named token (like 'for').
///
/// Note that callers of this method are guarded by checking the
/// IdentifierInfo's 'isHandleIdentifierCase' bit. If this method changes, the
/// IdentifierInfo methods that compute these properties will need to change to
/// match.
void Preprocessor::HandleIdentifier(Token &Identifier) {
assert(Identifier.getIdentifierInfo() &&
"Can't handle identifiers without identifier info!");
IdentifierInfo &II = *Identifier.getIdentifierInfo();
// If this identifier was poisoned, and if it was not produced from a macro
// expansion, emit an error.
if (II.isPoisoned() && CurPPLexer) {
if (&II != Ident__VA_ARGS__) // We warn about __VA_ARGS__ with poisoning.
Diag(Identifier, diag::err_pp_used_poisoned_id);
else
Diag(Identifier, diag::ext_pp_bad_vaargs_use);
}
// If this is a macro to be expanded, do it.
if (MacroInfo *MI = getMacroInfo(&II)) {
if (!DisableMacroExpansion && !Identifier.isExpandDisabled()) {
if (MI->isEnabled()) {
if (!HandleMacroExpandedIdentifier(Identifier, MI))
return;
} else {
// C99 6.10.3.4p2 says that a disabled macro may never again be
// expanded, even if it's in a context where it could be expanded in the
// future.
Identifier.setFlag(Token::DisableExpand);
}
}
}
// C++ 2.11p2: If this is an alternative representation of a C++ operator,
// then we act as if it is the actual operator and not the textual
// representation of it.
if (II.isCPlusPlusOperatorKeyword())
Identifier.setIdentifierInfo(0);
// If this is an extension token, diagnose its use.
// We avoid diagnosing tokens that originate from macro definitions.
// FIXME: This warning is disabled in cases where it shouldn't be,
// like "#define TY typeof", "TY(1) x".
if (II.isExtensionToken() && !DisableMacroExpansion)
Diag(Identifier, diag::ext_token_used);
}
void Preprocessor::AddCommentHandler(CommentHandler *Handler) {
assert(Handler && "NULL comment handler");
assert(std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler) ==
CommentHandlers.end() && "Comment handler already registered");
CommentHandlers.push_back(Handler);
}
void Preprocessor::RemoveCommentHandler(CommentHandler *Handler) {
std::vector<CommentHandler *>::iterator Pos
= std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler);
assert(Pos != CommentHandlers.end() && "Comment handler not registered");
CommentHandlers.erase(Pos);
}
bool Preprocessor::HandleComment(Token &result, SourceRange Comment) {
bool AnyPendingTokens = false;
for (std::vector<CommentHandler *>::iterator H = CommentHandlers.begin(),
HEnd = CommentHandlers.end();
H != HEnd; ++H) {
if ((*H)->HandleComment(*this, Comment))
AnyPendingTokens = true;
}
if (!AnyPendingTokens || getCommentRetentionState())
return false;
Lex(result);
return true;
}
CommentHandler::~CommentHandler() { }
void Preprocessor::createPreprocessingRecord() {
if (Record)
return;
Record = new PreprocessingRecord;
addPPCallbacks(Record);
}
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