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//===--- CacheTokens.cpp - Caching of lexer tokens for PCH support --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides a possible implementation of PCH support for Clang that is
// based on caching lexed tokens and identifiers.
//
//===----------------------------------------------------------------------===//
#include "clang.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
typedef llvm::DenseMap<const FileEntry*,uint64_t> PCHMap;
typedef llvm::DenseMap<const IdentifierInfo*,uint64_t> IDMap;
static void Emit32(llvm::raw_ostream& Out, uint32_t V) {
#if 0
Out << (unsigned char)(V);
Out << (unsigned char)(V >> 8);
Out << (unsigned char)(V >> 16);
Out << (unsigned char)(V >> 24);
#else
Out << V;
#endif
}
static void EmitOffset(llvm::raw_ostream& Out, uint64_t V) {
assert(((uint32_t) V) == V && "Offset exceeds 32 bits.");
Emit32(Out, (uint32_t) V);
}
static void Emit8(llvm::raw_ostream& Out, uint32_t V) {
Out << (unsigned char)(V);
}
static void EmitBuf(llvm::raw_ostream& Out, const char* I, const char* E) {
for ( ; I != E ; ++I) Out << *I;
}
static uint32_t ResolveID(IDMap& IM, uint32_t& idx, const IdentifierInfo* II) {
IDMap::iterator I = IM.find(II);
if (I == IM.end()) {
IM[II] = idx;
return idx++;
}
return I->second;
}
static void EmitToken(llvm::raw_ostream& Out, const Token& T,
uint32_t& idcount, IDMap& IM) {
Emit8(Out, T.getKind());
Emit8(Out, T.getFlags());
Emit32(Out, ResolveID(IM, idcount, T.getIdentifierInfo()));
Emit32(Out, T.getLocation().getRawEncoding());
Emit32(Out, T.getLength());
}
static void EmitIdentifier(llvm::raw_ostream& Out, const IdentifierInfo& II) {
uint32_t X = (uint32_t) II.getTokenID() << 19;
X |= (uint32_t) II.getBuiltinID() << 9;
X |= (uint32_t) II.getObjCKeywordID() << 4;
if (II.hasMacroDefinition()) X |= 0x8;
if (II.isExtensionToken()) X |= 0x4;
if (II.isPoisoned()) X |= 0x2;
if (II.isCPlusPlusOperatorKeyword()) X |= 0x1;
Emit32(Out, X);
}
static uint64_t EmitIdentifierTable(llvm::raw_fd_ostream& Out,
const IdentifierTable& T, const IDMap& IM) {
// Record the location within the PTH file.
uint64_t Off = Out.tell();
for (IdentifierTable::const_iterator I=T.begin(), E=T.end(); I!=E; ++I) {
const IdentifierInfo& II = I->getValue();
// Write out the persistent identifier.
IDMap::const_iterator IItr = IM.find(&II);
if (IItr == IM.end()) continue;
Emit32(Out, IItr->second);
EmitIdentifier(Out, II);
// Write out the keyword.
unsigned len = I->getKeyLength();
Emit32(Out, len);
const char* buf = I->getKeyData();
EmitBuf(Out, buf, buf+len);
}
return Off;
}
static uint64_t EmitFileTable(llvm::raw_fd_ostream& Out, SourceManager& SM,
PCHMap& PM) {
uint64_t off = Out.tell();
assert (0 && "Write out the table.");
return off;
}
static uint64_t LexTokens(llvm::raw_fd_ostream& Out, Lexer& L, Preprocessor& PP,
uint32_t& idcount, IDMap& IM) {
// Record the location within the token file.
uint64_t off = Out.tell();
Token Tok;
do {
L.LexFromRawLexer(Tok);
if (Tok.is(tok::identifier)) {
Tok.setIdentifierInfo(PP.LookUpIdentifierInfo(Tok));
}
else if (Tok.is(tok::hash) && Tok.isAtStartOfLine()) {
// Special processing for #include. Store the '#' token and lex
// the next token.
EmitToken(Out, Tok, idcount, IM);
L.LexFromRawLexer(Tok);
// Did we see 'include'/'import'/'include_next'?
if (!Tok.is(tok::identifier))
continue;
IdentifierInfo* II = PP.LookUpIdentifierInfo(Tok);
Tok.setIdentifierInfo(II);
tok::PPKeywordKind K = II->getPPKeywordID();
if (K == tok::pp_include || K == tok::pp_import ||
K == tok::pp_include_next) {
// Save the 'include' token.
EmitToken(Out, Tok, idcount, IM);
// Lex the next token as an include string.
L.setParsingPreprocessorDirective(true);
L.LexIncludeFilename(Tok);
L.setParsingPreprocessorDirective(false);
if (Tok.is(tok::identifier))
Tok.setIdentifierInfo(PP.LookUpIdentifierInfo(Tok));
}
}
}
while (EmitToken(Out, Tok, idcount, IM), Tok.isNot(tok::eof));
return off;
}
void clang::CacheTokens(Preprocessor& PP, const std::string& OutFile) {
// Lex through the entire file. This will populate SourceManager with
// all of the header information.
Token Tok;
PP.EnterMainSourceFile();
do { PP.Lex(Tok); } while (Tok.isNot(tok::eof));
// Iterate over all the files in SourceManager. Create a lexer
// for each file and cache the tokens.
SourceManager& SM = PP.getSourceManager();
const LangOptions& LOpts = PP.getLangOptions();
llvm::raw_ostream& os = llvm::errs();
PCHMap PM;
IDMap IM;
uint32_t idcount = 0;
std::string ErrMsg;
llvm::raw_fd_ostream Out(OutFile.c_str(), true, ErrMsg);
if (!ErrMsg.empty()) {
os << "PCH error: " << ErrMsg << "\n";
return;
}
for (SourceManager::fileid_iterator I=SM.fileid_begin(), E=SM.fileid_end();
I!=E; ++I) {
const SrcMgr::ContentCache* C = I.getFileIDInfo().getContentCache();
if (!C) continue;
const FileEntry* FE = C->Entry; // Does this entry correspond to a file?
if (!FE) continue;
PCHMap::iterator PI = PM.find(FE); // Have we already processed this file?
if (PI != PM.end()) continue;
const llvm::MemoryBuffer* B = C->Buffer;
if (!B) continue;
Lexer L(SourceLocation::getFileLoc(I.getFileID(), 0), LOpts,
B->getBufferStart(), B->getBufferEnd(), B);
PM[FE] = LexTokens(Out, L, PP, idcount, IM);
}
// Write out the identifier table.
uint64_t IdTableOff = EmitIdentifierTable(Out, PP.getIdentifierTable(), IM);
// Write out the file table.
uint64_t FileTableOff = EmitFileTable(Out, SM, PM);
// Finally, write out the offset table at the end.
EmitOffset(Out, IdTableOff);
EmitOffset(Out, FileTableOff);
}
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