llvm-project/llvm/lib/Support/SourceMgr.cpp

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//===- SourceMgr.cpp - Manager for Simple Source Buffers & Diagnostics ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the SourceMgr class. This class is used as a simple
// substrate for diagnostics, #include handling, and other low level things for
// simple parsers.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/SourceMgr.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/Locale.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
[Support] Make line-number cache robust against access patterns. Summary: The LLVM SourceMgr class (which is used indirectly by Swift, though not Clang) has a routine for looking up line numbers of SMLocs. This routine uses a shared, special-purpose cache that handles exactly one access pattern efficiently: looking up the line number of an SMLoc that points into the same buffer as the last query made to the SourceMgr, at a location in the buffer at or ahead of the last query. When this works it's fine, but when it fails it's catastrophic for performancer: one recent out-of-order access from a Swift utility routine ran for tens of seconds, spending 99% of its time repeatedly scanning buffers for '\n'. This change removes the shared cache from the SourceMgr and installs a new cache in each SrcBuffer. The per-SrcBuffer caches are also "full", in the sense that rather than caching a single last-query pointer, they cache _all_ the line-ending offsets, in a binary-searchable array, such that once it's populated (on first access), all subsequent access patterns run at the same speed. Performance measurements I've done show this is actually a little bit faster on real codebases (though only a couple fractions of a percent). Memory usage is up by a few tens to hundreds of bytes per SrcBuffer that has a line lookup done on it; I've attempted to minimize this by using dynamic selection of integer sized when storing offset arrays. But the main motive here is to make-impossible the cases we don't always see, that show up by surprise when there is an out-of-order access pattern. Reviewers: jordan_rose Reviewed By: jordan_rose Subscribers: probinson, llvm-commits Differential Revision: https://reviews.llvm.org/D45003 llvm-svn: 329470
2018-04-07 08:44:02 +08:00
#include <limits>
#include <memory>
#include <string>
#include <utility>
using namespace llvm;
static const size_t TabStop = 8;
unsigned SourceMgr::AddIncludeFile(const std::string &Filename,
SMLoc IncludeLoc,
std::string &IncludedFile) {
IncludedFile = Filename;
ErrorOr<std::unique_ptr<MemoryBuffer>> NewBufOrErr =
MemoryBuffer::getFile(IncludedFile);
// If the file didn't exist directly, see if it's in an include path.
for (unsigned i = 0, e = IncludeDirectories.size(); i != e && !NewBufOrErr;
++i) {
IncludedFile =
IncludeDirectories[i] + sys::path::get_separator().data() + Filename;
NewBufOrErr = MemoryBuffer::getFile(IncludedFile);
}
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if (!NewBufOrErr)
return 0;
return AddNewSourceBuffer(std::move(*NewBufOrErr), IncludeLoc);
}
unsigned SourceMgr::FindBufferContainingLoc(SMLoc Loc) const {
for (unsigned i = 0, e = Buffers.size(); i != e; ++i)
if (Loc.getPointer() >= Buffers[i].Buffer->getBufferStart() &&
// Use <= here so that a pointer to the null at the end of the buffer
// is included as part of the buffer.
Loc.getPointer() <= Buffers[i].Buffer->getBufferEnd())
return i + 1;
return 0;
}
[Support] Make line-number cache robust against access patterns. Summary: The LLVM SourceMgr class (which is used indirectly by Swift, though not Clang) has a routine for looking up line numbers of SMLocs. This routine uses a shared, special-purpose cache that handles exactly one access pattern efficiently: looking up the line number of an SMLoc that points into the same buffer as the last query made to the SourceMgr, at a location in the buffer at or ahead of the last query. When this works it's fine, but when it fails it's catastrophic for performancer: one recent out-of-order access from a Swift utility routine ran for tens of seconds, spending 99% of its time repeatedly scanning buffers for '\n'. This change removes the shared cache from the SourceMgr and installs a new cache in each SrcBuffer. The per-SrcBuffer caches are also "full", in the sense that rather than caching a single last-query pointer, they cache _all_ the line-ending offsets, in a binary-searchable array, such that once it's populated (on first access), all subsequent access patterns run at the same speed. Performance measurements I've done show this is actually a little bit faster on real codebases (though only a couple fractions of a percent). Memory usage is up by a few tens to hundreds of bytes per SrcBuffer that has a line lookup done on it; I've attempted to minimize this by using dynamic selection of integer sized when storing offset arrays. But the main motive here is to make-impossible the cases we don't always see, that show up by surprise when there is an out-of-order access pattern. Reviewers: jordan_rose Reviewed By: jordan_rose Subscribers: probinson, llvm-commits Differential Revision: https://reviews.llvm.org/D45003 llvm-svn: 329470
2018-04-07 08:44:02 +08:00
template <typename T>
unsigned SourceMgr::SrcBuffer::getLineNumber(const char *Ptr) const {
// Ensure OffsetCache is allocated and populated with offsets of all the
// '\n' bytes.
std::vector<T> *Offsets = nullptr;
if (OffsetCache.isNull()) {
Offsets = new std::vector<T>();
OffsetCache = Offsets;
size_t Sz = Buffer->getBufferSize();
assert(Sz <= std::numeric_limits<T>::max());
StringRef S = Buffer->getBuffer();
for (size_t N = 0; N < Sz; ++N) {
if (S[N] == '\n') {
Offsets->push_back(static_cast<T>(N));
}
}
} else {
Offsets = OffsetCache.get<std::vector<T> *>();
}
const char *BufStart = Buffer->getBufferStart();
assert(Ptr >= BufStart && Ptr <= Buffer->getBufferEnd());
ptrdiff_t PtrDiff = Ptr - BufStart;
assert(PtrDiff >= 0 && static_cast<size_t>(PtrDiff) <= std::numeric_limits<T>::max());
T PtrOffset = static_cast<T>(PtrDiff);
// llvm::lower_bound gives the number of EOL before PtrOffset. Add 1 to get
// the line number.
return llvm::lower_bound(*Offsets, PtrOffset) - Offsets->begin() + 1;
[Support] Make line-number cache robust against access patterns. Summary: The LLVM SourceMgr class (which is used indirectly by Swift, though not Clang) has a routine for looking up line numbers of SMLocs. This routine uses a shared, special-purpose cache that handles exactly one access pattern efficiently: looking up the line number of an SMLoc that points into the same buffer as the last query made to the SourceMgr, at a location in the buffer at or ahead of the last query. When this works it's fine, but when it fails it's catastrophic for performancer: one recent out-of-order access from a Swift utility routine ran for tens of seconds, spending 99% of its time repeatedly scanning buffers for '\n'. This change removes the shared cache from the SourceMgr and installs a new cache in each SrcBuffer. The per-SrcBuffer caches are also "full", in the sense that rather than caching a single last-query pointer, they cache _all_ the line-ending offsets, in a binary-searchable array, such that once it's populated (on first access), all subsequent access patterns run at the same speed. Performance measurements I've done show this is actually a little bit faster on real codebases (though only a couple fractions of a percent). Memory usage is up by a few tens to hundreds of bytes per SrcBuffer that has a line lookup done on it; I've attempted to minimize this by using dynamic selection of integer sized when storing offset arrays. But the main motive here is to make-impossible the cases we don't always see, that show up by surprise when there is an out-of-order access pattern. Reviewers: jordan_rose Reviewed By: jordan_rose Subscribers: probinson, llvm-commits Differential Revision: https://reviews.llvm.org/D45003 llvm-svn: 329470
2018-04-07 08:44:02 +08:00
}
SourceMgr::SrcBuffer::SrcBuffer(SourceMgr::SrcBuffer &&Other)
: Buffer(std::move(Other.Buffer)),
OffsetCache(Other.OffsetCache),
IncludeLoc(Other.IncludeLoc) {
Other.OffsetCache = nullptr;
}
SourceMgr::SrcBuffer::~SrcBuffer() {
if (!OffsetCache.isNull()) {
if (OffsetCache.is<std::vector<uint8_t>*>())
delete OffsetCache.get<std::vector<uint8_t>*>();
else if (OffsetCache.is<std::vector<uint16_t>*>())
delete OffsetCache.get<std::vector<uint16_t>*>();
else if (OffsetCache.is<std::vector<uint32_t>*>())
delete OffsetCache.get<std::vector<uint32_t>*>();
else
delete OffsetCache.get<std::vector<uint64_t>*>();
OffsetCache = nullptr;
}
}
std::pair<unsigned, unsigned>
SourceMgr::getLineAndColumn(SMLoc Loc, unsigned BufferID) const {
if (!BufferID)
BufferID = FindBufferContainingLoc(Loc);
assert(BufferID && "Invalid Location!");
2010-01-27 18:13:11 +08:00
[Support] Make line-number cache robust against access patterns. Summary: The LLVM SourceMgr class (which is used indirectly by Swift, though not Clang) has a routine for looking up line numbers of SMLocs. This routine uses a shared, special-purpose cache that handles exactly one access pattern efficiently: looking up the line number of an SMLoc that points into the same buffer as the last query made to the SourceMgr, at a location in the buffer at or ahead of the last query. When this works it's fine, but when it fails it's catastrophic for performancer: one recent out-of-order access from a Swift utility routine ran for tens of seconds, spending 99% of its time repeatedly scanning buffers for '\n'. This change removes the shared cache from the SourceMgr and installs a new cache in each SrcBuffer. The per-SrcBuffer caches are also "full", in the sense that rather than caching a single last-query pointer, they cache _all_ the line-ending offsets, in a binary-searchable array, such that once it's populated (on first access), all subsequent access patterns run at the same speed. Performance measurements I've done show this is actually a little bit faster on real codebases (though only a couple fractions of a percent). Memory usage is up by a few tens to hundreds of bytes per SrcBuffer that has a line lookup done on it; I've attempted to minimize this by using dynamic selection of integer sized when storing offset arrays. But the main motive here is to make-impossible the cases we don't always see, that show up by surprise when there is an out-of-order access pattern. Reviewers: jordan_rose Reviewed By: jordan_rose Subscribers: probinson, llvm-commits Differential Revision: https://reviews.llvm.org/D45003 llvm-svn: 329470
2018-04-07 08:44:02 +08:00
auto &SB = getBufferInfo(BufferID);
const char *Ptr = Loc.getPointer();
size_t Sz = SB.Buffer->getBufferSize();
unsigned LineNo;
if (Sz <= std::numeric_limits<uint8_t>::max())
LineNo = SB.getLineNumber<uint8_t>(Ptr);
else if (Sz <= std::numeric_limits<uint16_t>::max())
LineNo = SB.getLineNumber<uint16_t>(Ptr);
else if (Sz <= std::numeric_limits<uint32_t>::max())
LineNo = SB.getLineNumber<uint32_t>(Ptr);
else
LineNo = SB.getLineNumber<uint64_t>(Ptr);
const char *BufStart = SB.Buffer->getBufferStart();
size_t NewlineOffs = StringRef(BufStart, Ptr-BufStart).find_last_of("\n\r");
if (NewlineOffs == StringRef::npos) NewlineOffs = ~(size_t)0;
return std::make_pair(LineNo, Ptr-BufStart-NewlineOffs);
}
void SourceMgr::PrintIncludeStack(SMLoc IncludeLoc, raw_ostream &OS) const {
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if (IncludeLoc == SMLoc()) return; // Top of stack.
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unsigned CurBuf = FindBufferContainingLoc(IncludeLoc);
assert(CurBuf && "Invalid or unspecified location!");
PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
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OS << "Included from "
<< getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
<< ":" << FindLineNumber(IncludeLoc, CurBuf) << ":\n";
}
SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
const Twine &Msg,
ArrayRef<SMRange> Ranges,
ArrayRef<SMFixIt> FixIts) const {
// First thing to do: find the current buffer containing the specified
// location to pull out the source line.
SmallVector<std::pair<unsigned, unsigned>, 4> ColRanges;
std::pair<unsigned, unsigned> LineAndCol;
StringRef BufferID = "<unknown>";
std::string LineStr;
if (Loc.isValid()) {
unsigned CurBuf = FindBufferContainingLoc(Loc);
assert(CurBuf && "Invalid or unspecified location!");
const MemoryBuffer *CurMB = getMemoryBuffer(CurBuf);
BufferID = CurMB->getBufferIdentifier();
// Scan backward to find the start of the line.
const char *LineStart = Loc.getPointer();
const char *BufStart = CurMB->getBufferStart();
while (LineStart != BufStart && LineStart[-1] != '\n' &&
LineStart[-1] != '\r')
--LineStart;
// Get the end of the line.
const char *LineEnd = Loc.getPointer();
const char *BufEnd = CurMB->getBufferEnd();
while (LineEnd != BufEnd && LineEnd[0] != '\n' && LineEnd[0] != '\r')
++LineEnd;
LineStr = std::string(LineStart, LineEnd);
// Convert any ranges to column ranges that only intersect the line of the
// location.
for (unsigned i = 0, e = Ranges.size(); i != e; ++i) {
SMRange R = Ranges[i];
if (!R.isValid()) continue;
// If the line doesn't contain any part of the range, then ignore it.
if (R.Start.getPointer() > LineEnd || R.End.getPointer() < LineStart)
continue;
// Ignore pieces of the range that go onto other lines.
if (R.Start.getPointer() < LineStart)
R.Start = SMLoc::getFromPointer(LineStart);
if (R.End.getPointer() > LineEnd)
R.End = SMLoc::getFromPointer(LineEnd);
// Translate from SMLoc ranges to column ranges.
// FIXME: Handle multibyte characters.
ColRanges.push_back(std::make_pair(R.Start.getPointer()-LineStart,
R.End.getPointer()-LineStart));
}
LineAndCol = getLineAndColumn(Loc, CurBuf);
}
return SMDiagnostic(*this, Loc, BufferID, LineAndCol.first,
LineAndCol.second-1, Kind, Msg.str(),
LineStr, ColRanges, FixIts);
}
void SourceMgr::PrintMessage(raw_ostream &OS, const SMDiagnostic &Diagnostic,
bool ShowColors) const {
// Report the message with the diagnostic handler if present.
if (DiagHandler) {
DiagHandler(Diagnostic, DiagContext);
return;
}
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if (Diagnostic.getLoc().isValid()) {
unsigned CurBuf = FindBufferContainingLoc(Diagnostic.getLoc());
assert(CurBuf && "Invalid or unspecified location!");
PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
}
Diagnostic.print(nullptr, OS, ShowColors);
}
void SourceMgr::PrintMessage(raw_ostream &OS, SMLoc Loc,
SourceMgr::DiagKind Kind,
const Twine &Msg, ArrayRef<SMRange> Ranges,
ArrayRef<SMFixIt> FixIts, bool ShowColors) const {
PrintMessage(OS, GetMessage(Loc, Kind, Msg, Ranges, FixIts), ShowColors);
}
void SourceMgr::PrintMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
const Twine &Msg, ArrayRef<SMRange> Ranges,
ArrayRef<SMFixIt> FixIts, bool ShowColors) const {
PrintMessage(errs(), Loc, Kind, Msg, Ranges, FixIts, ShowColors);
}
//===----------------------------------------------------------------------===//
// SMDiagnostic Implementation
//===----------------------------------------------------------------------===//
SMDiagnostic::SMDiagnostic(const SourceMgr &sm, SMLoc L, StringRef FN, int Line,
int Col, SourceMgr::DiagKind Kind, StringRef Msg,
StringRef LineStr,
ArrayRef<std::pair<unsigned, unsigned>> Ranges,
ArrayRef<SMFixIt> Hints)
: SM(&sm), Loc(L), Filename(std::string(FN)), LineNo(Line), ColumnNo(Col),
Kind(Kind), Message(std::string(Msg)), LineContents(std::string(LineStr)),
Ranges(Ranges.vec()), FixIts(Hints.begin(), Hints.end()) {
llvm::sort(FixIts);
}
static void buildFixItLine(std::string &CaretLine, std::string &FixItLine,
ArrayRef<SMFixIt> FixIts, ArrayRef<char> SourceLine){
if (FixIts.empty())
return;
const char *LineStart = SourceLine.begin();
const char *LineEnd = SourceLine.end();
size_t PrevHintEndCol = 0;
for (ArrayRef<SMFixIt>::iterator I = FixIts.begin(), E = FixIts.end();
I != E; ++I) {
// If the fixit contains a newline or tab, ignore it.
if (I->getText().find_first_of("\n\r\t") != StringRef::npos)
continue;
SMRange R = I->getRange();
// If the line doesn't contain any part of the range, then ignore it.
if (R.Start.getPointer() > LineEnd || R.End.getPointer() < LineStart)
continue;
// Translate from SMLoc to column.
// Ignore pieces of the range that go onto other lines.
// FIXME: Handle multibyte characters in the source line.
unsigned FirstCol;
if (R.Start.getPointer() < LineStart)
FirstCol = 0;
else
FirstCol = R.Start.getPointer() - LineStart;
// If we inserted a long previous hint, push this one forwards, and add
// an extra space to show that this is not part of the previous
// completion. This is sort of the best we can do when two hints appear
// to overlap.
//
// Note that if this hint is located immediately after the previous
// hint, no space will be added, since the location is more important.
unsigned HintCol = FirstCol;
if (HintCol < PrevHintEndCol)
HintCol = PrevHintEndCol + 1;
// FIXME: This assertion is intended to catch unintended use of multibyte
// characters in fixits. If we decide to do this, we'll have to track
// separate byte widths for the source and fixit lines.
assert((size_t)sys::locale::columnWidth(I->getText()) ==
I->getText().size());
// This relies on one byte per column in our fixit hints.
unsigned LastColumnModified = HintCol + I->getText().size();
if (LastColumnModified > FixItLine.size())
FixItLine.resize(LastColumnModified, ' ');
std::copy(I->getText().begin(), I->getText().end(),
FixItLine.begin() + HintCol);
PrevHintEndCol = LastColumnModified;
// For replacements, mark the removal range with '~'.
// FIXME: Handle multibyte characters in the source line.
unsigned LastCol;
if (R.End.getPointer() >= LineEnd)
LastCol = LineEnd - LineStart;
else
LastCol = R.End.getPointer() - LineStart;
std::fill(&CaretLine[FirstCol], &CaretLine[LastCol], '~');
}
}
static void printSourceLine(raw_ostream &S, StringRef LineContents) {
// Print out the source line one character at a time, so we can expand tabs.
for (unsigned i = 0, e = LineContents.size(), OutCol = 0; i != e; ++i) {
size_t NextTab = LineContents.find('\t', i);
// If there were no tabs left, print the rest, we are done.
if (NextTab == StringRef::npos) {
S << LineContents.drop_front(i);
break;
}
// Otherwise, print from i to NextTab.
S << LineContents.slice(i, NextTab);
OutCol += NextTab - i;
i = NextTab;
// If we have a tab, emit at least one space, then round up to 8 columns.
do {
S << ' ';
++OutCol;
} while ((OutCol % TabStop) != 0);
}
S << '\n';
}
static bool isNonASCII(char c) {
return c & 0x80;
}
void SMDiagnostic::print(const char *ProgName, raw_ostream &OS,
bool ShowColors, bool ShowKindLabel) const {
{
WithColor S(OS, raw_ostream::SAVEDCOLOR, true, false, !ShowColors);
if (ProgName && ProgName[0])
S << ProgName << ": ";
if (!Filename.empty()) {
if (Filename == "-")
S << "<stdin>";
else
S << Filename;
if (LineNo != -1) {
S << ':' << LineNo;
if (ColumnNo != -1)
S << ':' << (ColumnNo + 1);
}
S << ": ";
}
}
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if (ShowKindLabel) {
switch (Kind) {
case SourceMgr::DK_Error:
WithColor::error(OS, "", !ShowColors);
break;
case SourceMgr::DK_Warning:
WithColor::warning(OS, "", !ShowColors);
break;
case SourceMgr::DK_Note:
WithColor::note(OS, "", !ShowColors);
break;
case SourceMgr::DK_Remark:
WithColor::remark(OS, "", !ShowColors);
break;
}
}
WithColor(OS, raw_ostream::SAVEDCOLOR, true, false, !ShowColors)
<< Message << '\n';
if (LineNo == -1 || ColumnNo == -1)
return;
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// FIXME: If there are multibyte or multi-column characters in the source, all
// our ranges will be wrong. To do this properly, we'll need a byte-to-column
// map like Clang's TextDiagnostic. For now, we'll just handle tabs by
// expanding them later, and bail out rather than show incorrect ranges and
// misaligned fixits for any other odd characters.
if (find_if(LineContents, isNonASCII) != LineContents.end()) {
printSourceLine(OS, LineContents);
return;
}
size_t NumColumns = LineContents.size();
// Build the line with the caret and ranges.
std::string CaretLine(NumColumns+1, ' ');
// Expand any ranges.
for (unsigned r = 0, e = Ranges.size(); r != e; ++r) {
std::pair<unsigned, unsigned> R = Ranges[r];
std::fill(&CaretLine[R.first],
&CaretLine[std::min((size_t)R.second, CaretLine.size())],
'~');
}
// Add any fix-its.
// FIXME: Find the beginning of the line properly for multibyte characters.
std::string FixItInsertionLine;
buildFixItLine(CaretLine, FixItInsertionLine, FixIts,
makeArrayRef(Loc.getPointer() - ColumnNo,
LineContents.size()));
// Finally, plop on the caret.
if (unsigned(ColumnNo) <= NumColumns)
CaretLine[ColumnNo] = '^';
else
CaretLine[NumColumns] = '^';
// ... and remove trailing whitespace so the output doesn't wrap for it. We
// know that the line isn't completely empty because it has the caret in it at
// least.
CaretLine.erase(CaretLine.find_last_not_of(' ')+1);
printSourceLine(OS, LineContents);
{
WithColor S(OS, raw_ostream::GREEN, true, false, !ShowColors);
// Print out the caret line, matching tabs in the source line.
for (unsigned i = 0, e = CaretLine.size(), OutCol = 0; i != e; ++i) {
if (i >= LineContents.size() || LineContents[i] != '\t') {
S << CaretLine[i];
++OutCol;
continue;
}
// Okay, we have a tab. Insert the appropriate number of characters.
do {
S << CaretLine[i];
++OutCol;
} while ((OutCol % TabStop) != 0);
}
S << '\n';
}
// Print out the replacement line, matching tabs in the source line.
if (FixItInsertionLine.empty())
return;
for (size_t i = 0, e = FixItInsertionLine.size(), OutCol = 0; i < e; ++i) {
if (i >= LineContents.size() || LineContents[i] != '\t') {
OS << FixItInsertionLine[i];
++OutCol;
continue;
}
// Okay, we have a tab. Insert the appropriate number of characters.
do {
OS << FixItInsertionLine[i];
// FIXME: This is trying not to break up replacements, but then to re-sync
// with the tabs between replacements. This will fail, though, if two
// fix-it replacements are exactly adjacent, or if a fix-it contains a
// space. Really we should be precomputing column widths, which we'll
// need anyway for multibyte chars.
if (FixItInsertionLine[i] != ' ')
++i;
++OutCol;
} while (((OutCol % TabStop) != 0) && i != e);
}
OS << '\n';
}