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llvm-project/llvm/lib/DebugInfo/MSF/MSFBuilder.cpp

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//===- MSFBuilder.cpp -----------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/MSF/MSFBuilder.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/DebugInfo/MSF/MSFError.h"
#include "llvm/DebugInfo/MSF/MappedBlockStream.h"
#include "llvm/Support/BinaryByteStream.h"
#include "llvm/Support/BinaryStreamWriter.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileOutputBuffer.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <cstring>
#include <memory>
#include <utility>
#include <vector>
using namespace llvm;
using namespace llvm::msf;
using namespace llvm::support;
static const uint32_t kSuperBlockBlock = 0;
static const uint32_t kFreePageMap0Block = 1;
static const uint32_t kFreePageMap1Block = 2;
static const uint32_t kNumReservedPages = 3;
static const uint32_t kDefaultFreePageMap = kFreePageMap1Block;
static const uint32_t kDefaultBlockMapAddr = kNumReservedPages;
MSFBuilder::MSFBuilder(uint32_t BlockSize, uint32_t MinBlockCount, bool CanGrow,
BumpPtrAllocator &Allocator)
: Allocator(Allocator), IsGrowable(CanGrow),
FreePageMap(kDefaultFreePageMap), BlockSize(BlockSize),
BlockMapAddr(kDefaultBlockMapAddr), FreeBlocks(MinBlockCount, true) {
FreeBlocks[kSuperBlockBlock] = false;
FreeBlocks[kFreePageMap0Block] = false;
FreeBlocks[kFreePageMap1Block] = false;
FreeBlocks[BlockMapAddr] = false;
}
Expected<MSFBuilder> MSFBuilder::create(BumpPtrAllocator &Allocator,
uint32_t BlockSize,
uint32_t MinBlockCount, bool CanGrow) {
if (!isValidBlockSize(BlockSize))
return make_error<MSFError>(msf_error_code::invalid_format,
"The requested block size is unsupported");
return MSFBuilder(BlockSize,
std::max(MinBlockCount, msf::getMinimumBlockCount()),
CanGrow, Allocator);
}
Error MSFBuilder::setBlockMapAddr(uint32_t Addr) {
if (Addr == BlockMapAddr)
return Error::success();
if (Addr >= FreeBlocks.size()) {
if (!IsGrowable)
return make_error<MSFError>(msf_error_code::insufficient_buffer,
"Cannot grow the number of blocks");
FreeBlocks.resize(Addr + 1, true);
}
if (!isBlockFree(Addr))
return make_error<MSFError>(
msf_error_code::block_in_use,
"Requested block map address is already in use");
FreeBlocks[BlockMapAddr] = true;
FreeBlocks[Addr] = false;
BlockMapAddr = Addr;
return Error::success();
}
void MSFBuilder::setFreePageMap(uint32_t Fpm) { FreePageMap = Fpm; }
void MSFBuilder::setUnknown1(uint32_t Unk1) { Unknown1 = Unk1; }
Error MSFBuilder::setDirectoryBlocksHint(ArrayRef<uint32_t> DirBlocks) {
for (auto B : DirectoryBlocks)
FreeBlocks[B] = true;
for (auto B : DirBlocks) {
if (!isBlockFree(B)) {
return make_error<MSFError>(msf_error_code::unspecified,
"Attempt to reuse an allocated block");
}
FreeBlocks[B] = false;
}
DirectoryBlocks = DirBlocks;
return Error::success();
}
Error MSFBuilder::allocateBlocks(uint32_t NumBlocks,
MutableArrayRef<uint32_t> Blocks) {
if (NumBlocks == 0)
return Error::success();
uint32_t NumFreeBlocks = FreeBlocks.count();
if (NumFreeBlocks < NumBlocks) {
if (!IsGrowable)
return make_error<MSFError>(msf_error_code::insufficient_buffer,
"There are no free Blocks in the file");
uint32_t AllocBlocks = NumBlocks - NumFreeBlocks;
uint32_t OldBlockCount = FreeBlocks.size();
uint32_t NewBlockCount = AllocBlocks + OldBlockCount;
uint32_t NextFpmBlock = alignTo(OldBlockCount, BlockSize) + 1;
FreeBlocks.resize(NewBlockCount, true);
// If we crossed over an fpm page, we actually need to allocate 2 extra
// blocks for each FPM group crossed and mark both blocks from the group as
// used. FPM blocks are marked as allocated regardless of whether or not
// they ultimately describe the status of blocks in the file. This means
// that not only are extraneous blocks at the end of the main FPM marked as
// allocated, but also blocks from the alternate FPM are always marked as
// allocated.
while (NextFpmBlock < NewBlockCount) {
NewBlockCount += 2;
FreeBlocks.resize(NewBlockCount, true);
FreeBlocks.reset(NextFpmBlock, NextFpmBlock + 2);
NextFpmBlock += BlockSize;
}
}
int I = 0;
int Block = FreeBlocks.find_first();
do {
assert(Block != -1 && "We ran out of Blocks!");
uint32_t NextBlock = static_cast<uint32_t>(Block);
Blocks[I++] = NextBlock;
FreeBlocks.reset(NextBlock);
Block = FreeBlocks.find_next(Block);
} while (--NumBlocks > 0);
return Error::success();
}
uint32_t MSFBuilder::getNumUsedBlocks() const {
return getTotalBlockCount() - getNumFreeBlocks();
}
uint32_t MSFBuilder::getNumFreeBlocks() const { return FreeBlocks.count(); }
uint32_t MSFBuilder::getTotalBlockCount() const { return FreeBlocks.size(); }
bool MSFBuilder::isBlockFree(uint32_t Idx) const { return FreeBlocks[Idx]; }
Expected<uint32_t> MSFBuilder::addStream(uint32_t Size,
ArrayRef<uint32_t> Blocks) {
// Add a new stream mapped to the specified blocks. Verify that the specified
// blocks are both necessary and sufficient for holding the requested number
// of bytes, and verify that all requested blocks are free.
uint32_t ReqBlocks = bytesToBlocks(Size, BlockSize);
if (ReqBlocks != Blocks.size())
return make_error<MSFError>(
msf_error_code::invalid_format,
"Incorrect number of blocks for requested stream size");
for (auto Block : Blocks) {
if (Block >= FreeBlocks.size())
FreeBlocks.resize(Block + 1, true);
if (!FreeBlocks.test(Block))
return make_error<MSFError>(
msf_error_code::unspecified,
"Attempt to re-use an already allocated block");
}
// Mark all the blocks occupied by the new stream as not free.
for (auto Block : Blocks) {
FreeBlocks.reset(Block);
}
StreamData.push_back(std::make_pair(Size, Blocks));
return StreamData.size() - 1;
}
Expected<uint32_t> MSFBuilder::addStream(uint32_t Size) {
uint32_t ReqBlocks = bytesToBlocks(Size, BlockSize);
std::vector<uint32_t> NewBlocks;
NewBlocks.resize(ReqBlocks);
if (auto EC = allocateBlocks(ReqBlocks, NewBlocks))
return std::move(EC);
StreamData.push_back(std::make_pair(Size, NewBlocks));
return StreamData.size() - 1;
}
Error MSFBuilder::setStreamSize(uint32_t Idx, uint32_t Size) {
uint32_t OldSize = getStreamSize(Idx);
if (OldSize == Size)
return Error::success();
uint32_t NewBlocks = bytesToBlocks(Size, BlockSize);
uint32_t OldBlocks = bytesToBlocks(OldSize, BlockSize);
if (NewBlocks > OldBlocks) {
uint32_t AddedBlocks = NewBlocks - OldBlocks;
// If we're growing, we have to allocate new Blocks.
std::vector<uint32_t> AddedBlockList;
AddedBlockList.resize(AddedBlocks);
if (auto EC = allocateBlocks(AddedBlocks, AddedBlockList))
return EC;
auto &CurrentBlocks = StreamData[Idx].second;
CurrentBlocks.insert(CurrentBlocks.end(), AddedBlockList.begin(),
AddedBlockList.end());
} else if (OldBlocks > NewBlocks) {
// For shrinking, free all the Blocks in the Block map, update the stream
// data, then shrink the directory.
uint32_t RemovedBlocks = OldBlocks - NewBlocks;
auto CurrentBlocks = ArrayRef<uint32_t>(StreamData[Idx].second);
auto RemovedBlockList = CurrentBlocks.drop_front(NewBlocks);
for (auto P : RemovedBlockList)
FreeBlocks[P] = true;
StreamData[Idx].second = CurrentBlocks.drop_back(RemovedBlocks);
}
StreamData[Idx].first = Size;
return Error::success();
}
uint32_t MSFBuilder::getNumStreams() const { return StreamData.size(); }
uint32_t MSFBuilder::getStreamSize(uint32_t StreamIdx) const {
return StreamData[StreamIdx].first;
}
ArrayRef<uint32_t> MSFBuilder::getStreamBlocks(uint32_t StreamIdx) const {
return StreamData[StreamIdx].second;
}
uint32_t MSFBuilder::computeDirectoryByteSize() const {
// The directory has the following layout, where each item is a ulittle32_t:
// NumStreams
// StreamSizes[NumStreams]
// StreamBlocks[NumStreams][]
uint32_t Size = sizeof(ulittle32_t); // NumStreams
Size += StreamData.size() * sizeof(ulittle32_t); // StreamSizes
for (const auto &D : StreamData) {
uint32_t ExpectedNumBlocks = bytesToBlocks(D.first, BlockSize);
assert(ExpectedNumBlocks == D.second.size() &&
"Unexpected number of blocks");
Size += ExpectedNumBlocks * sizeof(ulittle32_t);
}
return Size;
}
Expected<MSFLayout> MSFBuilder::generateLayout() {
SuperBlock *SB = Allocator.Allocate<SuperBlock>();
MSFLayout L;
L.SB = SB;
std::memcpy(SB->MagicBytes, Magic, sizeof(Magic));
SB->BlockMapAddr = BlockMapAddr;
SB->BlockSize = BlockSize;
SB->NumDirectoryBytes = computeDirectoryByteSize();
SB->FreeBlockMapBlock = FreePageMap;
SB->Unknown1 = Unknown1;
uint32_t NumDirectoryBlocks = bytesToBlocks(SB->NumDirectoryBytes, BlockSize);
if (NumDirectoryBlocks > DirectoryBlocks.size()) {
// Our hint wasn't enough to satisfy the entire directory. Allocate
// remaining pages.
std::vector<uint32_t> ExtraBlocks;
uint32_t NumExtraBlocks = NumDirectoryBlocks - DirectoryBlocks.size();
ExtraBlocks.resize(NumExtraBlocks);
if (auto EC = allocateBlocks(NumExtraBlocks, ExtraBlocks))
return std::move(EC);
DirectoryBlocks.insert(DirectoryBlocks.end(), ExtraBlocks.begin(),
ExtraBlocks.end());
} else if (NumDirectoryBlocks < DirectoryBlocks.size()) {
uint32_t NumUnnecessaryBlocks = DirectoryBlocks.size() - NumDirectoryBlocks;
for (auto B :
ArrayRef<uint32_t>(DirectoryBlocks).drop_back(NumUnnecessaryBlocks))
FreeBlocks[B] = true;
DirectoryBlocks.resize(NumDirectoryBlocks);
}
// Don't set the number of blocks in the file until after allocating Blocks
// for the directory, since the allocation might cause the file to need to
// grow.
SB->NumBlocks = FreeBlocks.size();
ulittle32_t *DirBlocks = Allocator.Allocate<ulittle32_t>(NumDirectoryBlocks);
std::uninitialized_copy_n(DirectoryBlocks.begin(), NumDirectoryBlocks,
DirBlocks);
L.DirectoryBlocks = ArrayRef<ulittle32_t>(DirBlocks, NumDirectoryBlocks);
// The stream sizes should be re-allocated as a stable pointer and the stream
// map should have each of its entries allocated as a separate stable pointer.
if (!StreamData.empty()) {
ulittle32_t *Sizes = Allocator.Allocate<ulittle32_t>(StreamData.size());
L.StreamSizes = ArrayRef<ulittle32_t>(Sizes, StreamData.size());
L.StreamMap.resize(StreamData.size());
for (uint32_t I = 0; I < StreamData.size(); ++I) {
Sizes[I] = StreamData[I].first;
ulittle32_t *BlockList =
Allocator.Allocate<ulittle32_t>(StreamData[I].second.size());
std::uninitialized_copy_n(StreamData[I].second.begin(),
StreamData[I].second.size(), BlockList);
L.StreamMap[I] =
ArrayRef<ulittle32_t>(BlockList, StreamData[I].second.size());
}
}
L.FreePageMap = FreeBlocks;
return L;
}
static void commitFpm(WritableBinaryStream &MsfBuffer, const MSFLayout &Layout,
BumpPtrAllocator &Allocator) {
auto FpmStream =
WritableMappedBlockStream::createFpmStream(Layout, MsfBuffer, Allocator);
// We only need to create the alt fpm stream so that it gets initialized.
WritableMappedBlockStream::createFpmStream(Layout, MsfBuffer, Allocator,
true);
uint32_t BI = 0;
BinaryStreamWriter FpmWriter(*FpmStream);
while (BI < Layout.SB->NumBlocks) {
uint8_t ThisByte = 0;
for (uint32_t I = 0; I < 8; ++I) {
bool IsFree =
(BI < Layout.SB->NumBlocks) ? Layout.FreePageMap.test(BI) : true;
uint8_t Mask = uint8_t(IsFree) << I;
ThisByte |= Mask;
++BI;
}
cantFail(FpmWriter.writeObject(ThisByte));
}
assert(FpmWriter.bytesRemaining() == 0);
}
Expected<FileBufferByteStream> MSFBuilder::commit(StringRef Path,
MSFLayout &Layout) {
Expected<MSFLayout> L = generateLayout();
if (!L)
return L.takeError();
Layout = std::move(*L);
uint64_t FileSize = Layout.SB->BlockSize * Layout.SB->NumBlocks;
auto OutFileOrError = FileOutputBuffer::create(Path, FileSize);
if (auto EC = OutFileOrError.takeError())
return std::move(EC);
FileBufferByteStream Buffer(std::move(*OutFileOrError),
llvm::support::little);
BinaryStreamWriter Writer(Buffer);
if (auto EC = Writer.writeObject(*Layout.SB))
return std::move(EC);
commitFpm(Buffer, Layout, Allocator);
uint32_t BlockMapOffset =
msf::blockToOffset(Layout.SB->BlockMapAddr, Layout.SB->BlockSize);
Writer.setOffset(BlockMapOffset);
if (auto EC = Writer.writeArray(Layout.DirectoryBlocks))
return std::move(EC);
auto DirStream = WritableMappedBlockStream::createDirectoryStream(
Layout, Buffer, Allocator);
BinaryStreamWriter DW(*DirStream);
if (auto EC = DW.writeInteger<uint32_t>(Layout.StreamSizes.size()))
return std::move(EC);
if (auto EC = DW.writeArray(Layout.StreamSizes))
return std::move(EC);
for (const auto &Blocks : Layout.StreamMap) {
if (auto EC = DW.writeArray(Blocks))
return std::move(EC);
}
return std::move(Buffer);
}
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