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//===--- SourceManager.cpp - Track and cache source files -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SourceManager interface.
//
//===----------------------------------------------------------------------===//
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/FileManager.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/System/Path.h"
#include <algorithm>
#include <iostream>
#include <fcntl.h>
using namespace clang;
using namespace SrcMgr;
using llvm::MemoryBuffer;
SourceManager::~SourceManager() {
for (std::map<const FileEntry *, FileInfo>::iterator I = FileInfos.begin(),
E = FileInfos.end(); I != E; ++I) {
delete I->second.Buffer;
delete[] I->second.SourceLineCache;
}
for (std::list<InfoRec>::iterator I = MemBufferInfos.begin(),
E = MemBufferInfos.end(); I != E; ++I) {
delete I->second.Buffer;
delete[] I->second.SourceLineCache;
}
}
// FIXME: REMOVE THESE
#include <unistd.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/fcntl.h>
#include <cerrno>
static const MemoryBuffer *ReadFileFast(const FileEntry *FileEnt) {
#if 0
// FIXME: Reintroduce this and zap this function once the common llvm stuff
// is fast for the small case.
return MemoryBuffer::getFile(FileEnt->getName(), strlen(FileEnt->getName()),
FileEnt->getSize());
#endif
// If the file is larger than some threshold, use 'read', otherwise use mmap.
if (FileEnt->getSize() >= 4096*4)
return MemoryBuffer::getFile(FileEnt->getName(), strlen(FileEnt->getName()),
0, FileEnt->getSize());
MemoryBuffer *SB = MemoryBuffer::getNewUninitMemBuffer(FileEnt->getSize(),
FileEnt->getName());
char *BufPtr = const_cast<char*>(SB->getBufferStart());
int FD = ::open(FileEnt->getName(), O_RDONLY);
if (FD == -1) {
delete SB;
return 0;
}
unsigned BytesLeft = FileEnt->getSize();
while (BytesLeft) {
ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
if (NumRead != -1) {
BytesLeft -= NumRead;
BufPtr += NumRead;
} else if (errno == EINTR) {
// try again
} else {
// error reading.
close(FD);
delete SB;
return 0;
}
}
close(FD);
return SB;
}
/// getFileInfo - Create or return a cached FileInfo for the specified file.
///
const InfoRec *
SourceManager::getInfoRec(const FileEntry *FileEnt) {
assert(FileEnt && "Didn't specify a file entry to use?");
// Do we already have information about this file?
std::map<const FileEntry *, FileInfo>::iterator I =
FileInfos.lower_bound(FileEnt);
if (I != FileInfos.end() && I->first == FileEnt)
return &*I;
// Nope, get information.
const MemoryBuffer *File = ReadFileFast(FileEnt);
if (File == 0)
return 0;
const InfoRec &Entry =
*FileInfos.insert(I, std::make_pair(FileEnt, FileInfo()));
FileInfo &Info = const_cast<FileInfo &>(Entry.second);
Info.Buffer = File;
Info.SourceLineCache = 0;
Info.NumLines = 0;
return &Entry;
}
/// createMemBufferInfoRec - Create a new info record for the specified memory
/// buffer. This does no caching.
const InfoRec *
SourceManager::createMemBufferInfoRec(const MemoryBuffer *Buffer) {
// Add a new info record to the MemBufferInfos list and return it.
FileInfo FI;
FI.Buffer = Buffer;
FI.SourceLineCache = 0;
FI.NumLines = 0;
MemBufferInfos.push_back(InfoRec(0, FI));
return &MemBufferInfos.back();
}
/// createFileID - Create a new fileID for the specified InfoRec and include
/// position. This works regardless of whether the InfoRec corresponds to a
/// file or some other input source.
unsigned SourceManager::createFileID(const InfoRec *File,
SourceLocation IncludePos) {
// If FileEnt is really large (e.g. it's a large .i file), we may not be able
// to fit an arbitrary position in the file in the FilePos field. To handle
// this, we create one FileID for each chunk of the file that fits in a
// FilePos field.
unsigned FileSize = File->second.Buffer->getBufferSize();
if (FileSize+1 < (1 << SourceLocation::FilePosBits)) {
FileIDs.push_back(FileIDInfo::get(IncludePos, 0, File));
assert(FileIDs.size() < (1 << SourceLocation::FileIDBits) &&
"Ran out of file ID's!");
return FileIDs.size();
}
// Create one FileID for each chunk of the file.
unsigned Result = FileIDs.size()+1;
unsigned ChunkNo = 0;
while (1) {
FileIDs.push_back(FileIDInfo::get(IncludePos, ChunkNo++, File));
if (FileSize+1 < (1 << SourceLocation::FilePosBits)) break;
FileSize -= (1 << SourceLocation::FilePosBits);
}
assert(FileIDs.size() < (1 << SourceLocation::FileIDBits) &&
"Ran out of file ID's!");
return Result;
}
/// getInstantiationLoc - Return a new SourceLocation that encodes the fact
/// that a token from physloc PhysLoc should actually be referenced from
/// InstantiationLoc.
SourceLocation SourceManager::getInstantiationLoc(SourceLocation PhysLoc,
SourceLocation InstantLoc) {
// The specified source location may be a mapped location, due to a macro
// instantiation or #line directive. Strip off this information to find out
// where the characters are actually located.
PhysLoc = getPhysicalLoc(PhysLoc);
// Resolve InstantLoc down to a real logical location.
InstantLoc = getLogicalLoc(InstantLoc);
// If the last macro id is close to the currently requested location, try to
// reuse it. This implements a small cache.
for (int i = MacroIDs.size()-1, e = MacroIDs.size()-6; i >= 0 && i != e; --i){
MacroIDInfo &LastOne = MacroIDs[i];
// The instanitation point and source physloc have to exactly match to reuse
// (for now). We could allow "nearby" instantiations in the future.
if (LastOne.getInstantiationLoc() != InstantLoc ||
LastOne.getPhysicalLoc().getFileID() != PhysLoc.getFileID())
continue;
// Check to see if the physloc of the token came from near enough to reuse.
int PhysDelta = PhysLoc.getRawFilePos() -
LastOne.getPhysicalLoc().getRawFilePos();
if (SourceLocation::isValidMacroPhysOffs(PhysDelta))
return SourceLocation::getMacroLoc(i, PhysDelta, 0);
}
MacroIDs.push_back(MacroIDInfo::get(InstantLoc, PhysLoc));
return SourceLocation::getMacroLoc(MacroIDs.size()-1, 0, 0);
}
/// getCharacterData - Return a pointer to the start of the specified location
/// in the appropriate MemoryBuffer.
const char *SourceManager::getCharacterData(SourceLocation SL) const {
// Note that this is a hot function in the getSpelling() path, which is
// heavily used by -E mode.
SL = getPhysicalLoc(SL);
return getFileInfo(SL.getFileID())->Buffer->getBufferStart() +
getFullFilePos(SL);
}
/// getColumnNumber - Return the column # for the specified file position.
/// this is significantly cheaper to compute than the line number. This returns
/// zero if the column number isn't known.
unsigned SourceManager::getColumnNumber(SourceLocation Loc) const {
unsigned FileID = Loc.getFileID();
if (FileID == 0) return 0;
unsigned FilePos = getFullFilePos(Loc);
const MemoryBuffer *Buffer = getBuffer(FileID);
const char *Buf = Buffer->getBufferStart();
unsigned LineStart = FilePos;
while (LineStart && Buf[LineStart-1] != '\n' && Buf[LineStart-1] != '\r')
--LineStart;
return FilePos-LineStart+1;
}
/// getSourceName - This method returns the name of the file or buffer that
/// the SourceLocation specifies. This can be modified with #line directives,
/// etc.
const char *SourceManager::getSourceName(SourceLocation Loc) {
unsigned FileID = Loc.getFileID();
if (FileID == 0) return "";
return getFileInfo(FileID)->Buffer->getBufferIdentifier();
}
static void ComputeLineNumbers(FileInfo *FI) DISABLE_INLINE;
static void ComputeLineNumbers(FileInfo *FI) {
const MemoryBuffer *Buffer = FI->Buffer;
// Find the file offsets of all of the *physical* source lines. This does
// not look at trigraphs, escaped newlines, or anything else tricky.
std::vector<unsigned> LineOffsets;
// Line #1 starts at char 0.
LineOffsets.push_back(0);
const unsigned char *Buf = (const unsigned char *)Buffer->getBufferStart();
const unsigned char *End = (const unsigned char *)Buffer->getBufferEnd();
unsigned Offs = 0;
while (1) {
// Skip over the contents of the line.
// TODO: Vectorize this? This is very performance sensitive for programs
// with lots of diagnostics and in -E mode.
const unsigned char *NextBuf = (const unsigned char *)Buf;
while (*NextBuf != '\n' && *NextBuf != '\r' && *NextBuf != '\0')
++NextBuf;
Offs += NextBuf-Buf;
Buf = NextBuf;
if (Buf[0] == '\n' || Buf[0] == '\r') {
// If this is \n\r or \r\n, skip both characters.
if ((Buf[1] == '\n' || Buf[1] == '\r') && Buf[0] != Buf[1])
++Offs, ++Buf;
++Offs, ++Buf;
LineOffsets.push_back(Offs);
} else {
// Otherwise, this is a null. If end of file, exit.
if (Buf == End) break;
// Otherwise, skip the null.
++Offs, ++Buf;
}
}
LineOffsets.push_back(Offs);
// Copy the offsets into the FileInfo structure.
FI->NumLines = LineOffsets.size();
FI->SourceLineCache = new unsigned[LineOffsets.size()];
std::copy(LineOffsets.begin(), LineOffsets.end(), FI->SourceLineCache);
}
/// getLineNumber - Given a SourceLocation, return the physical line number
/// for the position indicated. This requires building and caching a table of
/// line offsets for the MemoryBuffer, so this is not cheap: use only when
/// about to emit a diagnostic.
unsigned SourceManager::getLineNumber(SourceLocation Loc) {
unsigned FileID = Loc.getFileID();
if (FileID == 0) return 0;
FileInfo *FileInfo;
if (LastLineNoFileIDQuery == FileID)
FileInfo = LastLineNoFileInfo;
else
FileInfo = getFileInfo(FileID);
// If this is the first use of line information for this buffer, compute the
/// SourceLineCache for it on demand.
if (FileInfo->SourceLineCache == 0)
ComputeLineNumbers(FileInfo);
// Okay, we know we have a line number table. Do a binary search to find the
// line number that this character position lands on.
unsigned *SourceLineCache = FileInfo->SourceLineCache;
unsigned *SourceLineCacheStart = SourceLineCache;
unsigned *SourceLineCacheEnd = SourceLineCache + FileInfo->NumLines;
unsigned QueriedFilePos = getFullFilePos(Loc)+1;
// If the previous query was to the same file, we know both the file pos from
// that query and the line number returned. This allows us to narrow the
// search space from the entire file to something near the match.
if (LastLineNoFileIDQuery == FileID) {
if (QueriedFilePos >= LastLineNoFilePos) {
SourceLineCache = SourceLineCache+LastLineNoResult-1;
// The query is likely to be nearby the previous one. Here we check to
// see if it is within 5, 10 or 20 lines. It can be far away in cases
// where big comment blocks and vertical whitespace eat up lines but
// contribute no tokens.
if (SourceLineCache+5 < SourceLineCacheEnd) {
if (SourceLineCache[5] > QueriedFilePos)
SourceLineCacheEnd = SourceLineCache+5;
else if (SourceLineCache+10 < SourceLineCacheEnd) {
if (SourceLineCache[10] > QueriedFilePos)
SourceLineCacheEnd = SourceLineCache+10;
else if (SourceLineCache+20 < SourceLineCacheEnd) {
if (SourceLineCache[20] > QueriedFilePos)
SourceLineCacheEnd = SourceLineCache+20;
}
}
}
} else {
SourceLineCacheEnd = SourceLineCache+LastLineNoResult+1;
}
}
// If the spread is large, do a "radix" test as our initial guess, based on
// the assumption that lines average to approximately the same length.
// NOTE: This is currently disabled, as it does not appear to be profitable in
// initial measurements.
if (0 && SourceLineCacheEnd-SourceLineCache > 20) {
unsigned FileLen = FileInfo->SourceLineCache[FileInfo->NumLines-1];
// Take a stab at guessing where it is.
unsigned ApproxPos = FileInfo->NumLines*QueriedFilePos / FileLen;
// Check for -10 and +10 lines.
unsigned LowerBound = std::max(int(ApproxPos-10), 0);
unsigned UpperBound = std::min(ApproxPos+10, FileLen);
// If the computed lower bound is less than the query location, move it in.
if (SourceLineCache < SourceLineCacheStart+LowerBound &&
SourceLineCacheStart[LowerBound] < QueriedFilePos)
SourceLineCache = SourceLineCacheStart+LowerBound;
// If the computed upper bound is greater than the query location, move it.
if (SourceLineCacheEnd > SourceLineCacheStart+UpperBound &&
SourceLineCacheStart[UpperBound] >= QueriedFilePos)
SourceLineCacheEnd = SourceLineCacheStart+UpperBound;
}
unsigned *Pos
= std::lower_bound(SourceLineCache, SourceLineCacheEnd, QueriedFilePos);
unsigned LineNo = Pos-SourceLineCacheStart;
LastLineNoFileIDQuery = FileID;
LastLineNoFileInfo = FileInfo;
LastLineNoFilePos = QueriedFilePos;
LastLineNoResult = LineNo;
return LineNo;
}
/// PrintStats - Print statistics to stderr.
///
void SourceManager::PrintStats() const {
std::cerr << "\n*** Source Manager Stats:\n";
std::cerr << FileInfos.size() << " files mapped, " << MemBufferInfos.size()
<< " mem buffers mapped, " << FileIDs.size()
<< " file ID's allocated.\n";
std::cerr << " " << FileIDs.size() << " normal buffer FileID's, "
<< MacroIDs.size() << " macro expansion FileID's.\n";
unsigned NumLineNumsComputed = 0;
unsigned NumFileBytesMapped = 0;
for (std::map<const FileEntry *, FileInfo>::const_iterator I =
FileInfos.begin(), E = FileInfos.end(); I != E; ++I) {
NumLineNumsComputed += I->second.SourceLineCache != 0;
NumFileBytesMapped += I->second.Buffer->getBufferSize();
}
std::cerr << NumFileBytesMapped << " bytes of files mapped, "
<< NumLineNumsComputed << " files with line #'s computed.\n";
}