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| author | Alon Zakai <azakai@google.com> | 2019-12-19 09:04:08 -0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-12-19 09:04:08 -0800 |
| commit | 4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6 (patch) | |
| tree | 91bffc2d47b1fe4bba01e7ada77006ef340bd138 /third_party/llvm-project/MemoryBuffer.cpp | |
| parent | 0048f5b004ddf50e750aa335d0be314a73852058 (diff) | |
| download | binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.tar.gz binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.tar.bz2 binaryen-4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6.zip | |
DWARF parsing and writing support using LLVM (#2520)
This imports LLVM code for DWARF handling. That code has the
Apache 2 license like us. It's also the same code used to
emit DWARF in the common toolchain, so it seems like a safe choice.
This adds two passes: --dwarfdump which runs the same code LLVM
runs for llvm-dwarfdump. This shows we can parse it ok, and will
be useful for debugging. And --dwarfupdate writes out the DWARF
sections (unchanged from what we read, so it just roundtrips - for
updating we need #2515).
This puts LLVM in thirdparty which is added here.
All the LLVM code is behind USE_LLVM_DWARF, which is on
by default, but off in JS for now, as it increases code size by 20%.
This current approach imports the LLVM files directly. This is not
how they are intended to be used, so it required a bunch of
local changes - more than I expected actually, for the platform-specific
stuff. For now this seems to work, so it may be good enough, but
in the long term we may want to switch to linking against libllvm.
A downside to doing that is that binaryen users would need to
have an LLVM build, and even in the waterfall builds we'd have a
problem - while we ship LLVM there anyhow, we constantly update
it, which means that binaryen would need to be on latest llvm all
the time too (which otherwise, given DWARF is quite stable, we
might not need to constantly update).
An even larger issue is that as I did this work I learned about how
DWARF works in LLVM, and while the reading code is easy to
reuse, the writing code is trickier. The main code path is heavily
integrated with the MC layer, which we don't have - we might want
to create a "fake MC layer" for that, but it sounds hard. Instead,
there is the YAML path which is used mostly for testing, and which
can convert DWARF to and from YAML and from binary. Using
the non-YAML parts there, we can convert binary DWARF to
the YAML layer's nice Info data, then convert that to binary. This
works, however, this is not the path LLVM uses normally, and it
supports only some basic DWARF sections - I had to add ranges
support, in fact. So if we need more complex things, we may end
up needing to use the MC layer approach, or consider some other
DWARF library. However, hopefully that should not affect the core
binaryen code which just calls a library for DWARF stuff.
Helps #2400
Diffstat (limited to 'third_party/llvm-project/MemoryBuffer.cpp')
| -rw-r--r-- | third_party/llvm-project/MemoryBuffer.cpp | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/third_party/llvm-project/MemoryBuffer.cpp b/third_party/llvm-project/MemoryBuffer.cpp new file mode 100644 index 000000000..79b93fd90 --- /dev/null +++ b/third_party/llvm-project/MemoryBuffer.cpp @@ -0,0 +1,355 @@ +//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===// +// +// 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 MemoryBuffer interface. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/MemoryBuffer.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/Config/config.h" +#include "llvm/Support/Errc.h" +#include "llvm/Support/Errno.h" +#include "llvm/Support/FileSystem.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/Path.h" +#include "llvm/Support/Process.h" +#include "llvm/Support/Program.h" +#include "llvm/Support/SmallVectorMemoryBuffer.h" +#include <cassert> +#include <cerrno> +#include <cstring> +#include <new> +#include <sys/types.h> +#include <system_error> +#if !defined(_MSC_VER) && !defined(__MINGW32__) +#include <unistd.h> +#else +#include <io.h> +#endif +using namespace llvm; + +//===----------------------------------------------------------------------===// +// MemoryBuffer implementation itself. +//===----------------------------------------------------------------------===// + +MemoryBuffer::~MemoryBuffer() { } + +/// init - Initialize this MemoryBuffer as a reference to externally allocated +/// memory, memory that we know is already null terminated. +void MemoryBuffer::init(const char *BufStart, const char *BufEnd, + bool RequiresNullTerminator) { + assert((!RequiresNullTerminator || BufEnd[0] == 0) && + "Buffer is not null terminated!"); + BufferStart = BufStart; + BufferEnd = BufEnd; +} + +//===----------------------------------------------------------------------===// +// MemoryBufferMem implementation. +//===----------------------------------------------------------------------===// + +/// CopyStringRef - Copies contents of a StringRef into a block of memory and +/// null-terminates it. +static void CopyStringRef(char *Memory, StringRef Data) { + if (!Data.empty()) + memcpy(Memory, Data.data(), Data.size()); + Memory[Data.size()] = 0; // Null terminate string. +} + +namespace { +struct NamedBufferAlloc { + const Twine &Name; + NamedBufferAlloc(const Twine &Name) : Name(Name) {} +}; +} + +void *operator new(size_t N, const NamedBufferAlloc &Alloc) { + SmallString<256> NameBuf; + StringRef NameRef = Alloc.Name.toStringRef(NameBuf); + + char *Mem = static_cast<char *>(operator new(N + NameRef.size() + 1)); + CopyStringRef(Mem + N, NameRef); + return Mem; +} + +namespace { +/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory. +template<typename MB> +class MemoryBufferMem : public MB { +public: + MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) { + MemoryBuffer::init(InputData.begin(), InputData.end(), + RequiresNullTerminator); + } + + /// Disable sized deallocation for MemoryBufferMem, because it has + /// tail-allocated data. + void operator delete(void *p) { ::operator delete(p); } + + StringRef getBufferIdentifier() const override { + // The name is stored after the class itself. + return StringRef(reinterpret_cast<const char *>(this + 1)); + } + + MemoryBuffer::BufferKind getBufferKind() const override { + return MemoryBuffer::MemoryBuffer_Malloc; + } +}; +} + +template <typename MB> +static ErrorOr<std::unique_ptr<MB>> +getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, + uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile); + +std::unique_ptr<MemoryBuffer> +MemoryBuffer::getMemBuffer(StringRef InputData, StringRef BufferName, + bool RequiresNullTerminator) { + auto *Ret = new (NamedBufferAlloc(BufferName)) + MemoryBufferMem<MemoryBuffer>(InputData, RequiresNullTerminator); + return std::unique_ptr<MemoryBuffer>(Ret); +} + +std::unique_ptr<MemoryBuffer> +MemoryBuffer::getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator) { + return std::unique_ptr<MemoryBuffer>(getMemBuffer( + Ref.getBuffer(), Ref.getBufferIdentifier(), RequiresNullTerminator)); +} + +static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> +getMemBufferCopyImpl(StringRef InputData, const Twine &BufferName) { + auto Buf = WritableMemoryBuffer::getNewUninitMemBuffer(InputData.size(), BufferName); + if (!Buf) + return make_error_code(errc::not_enough_memory); + memcpy(Buf->getBufferStart(), InputData.data(), InputData.size()); + return std::move(Buf); +} + +std::unique_ptr<MemoryBuffer> +MemoryBuffer::getMemBufferCopy(StringRef InputData, const Twine &BufferName) { + auto Buf = getMemBufferCopyImpl(InputData, BufferName); + if (Buf) + return std::move(*Buf); + return nullptr; +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getFileOrSTDIN(const Twine &Filename, int64_t FileSize, + bool RequiresNullTerminator) { + SmallString<256> NameBuf; + StringRef NameRef = Filename.toStringRef(NameBuf); + + if (NameRef == "-") + return getSTDIN(); + return getFile(Filename, FileSize, RequiresNullTerminator); +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getFileSlice(const Twine &FilePath, uint64_t MapSize, + uint64_t Offset, bool IsVolatile) { + return getFileAux<MemoryBuffer>(FilePath, -1, MapSize, Offset, false, + IsVolatile); +} + +//===----------------------------------------------------------------------===// +// MemoryBuffer::getFile implementation. +//===----------------------------------------------------------------------===// + +#if 0 // XXX BINARYEN +namespace { +/// Memory maps a file descriptor using sys::fs::mapped_file_region. +/// +/// This handles converting the offset into a legal offset on the platform. +template<typename MB> +class MemoryBufferMMapFile : public MB { + sys::fs::mapped_file_region MFR; + + static uint64_t getLegalMapOffset(uint64_t Offset) { + return Offset & ~(sys::fs::mapped_file_region::alignment() - 1); + } + + static uint64_t getLegalMapSize(uint64_t Len, uint64_t Offset) { + return Len + (Offset - getLegalMapOffset(Offset)); + } + + const char *getStart(uint64_t Len, uint64_t Offset) { + return MFR.const_data() + (Offset - getLegalMapOffset(Offset)); + } + +public: + MemoryBufferMMapFile(bool RequiresNullTerminator, sys::fs::file_t FD, uint64_t Len, + uint64_t Offset, std::error_code &EC) + : MFR(FD, MB::Mapmode, getLegalMapSize(Len, Offset), + getLegalMapOffset(Offset), EC) { + if (!EC) { + const char *Start = getStart(Len, Offset); + MemoryBuffer::init(Start, Start + Len, RequiresNullTerminator); + } + } + + /// Disable sized deallocation for MemoryBufferMMapFile, because it has + /// tail-allocated data. + void operator delete(void *p) { ::operator delete(p); } + + StringRef getBufferIdentifier() const override { + // The name is stored after the class itself. + return StringRef(reinterpret_cast<const char *>(this + 1)); + } + + MemoryBuffer::BufferKind getBufferKind() const override { + return MemoryBuffer::MemoryBuffer_MMap; + } +}; +} +#endif + +static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> +getMemoryBufferForStream(sys::fs::file_t FD, const Twine &BufferName) { + llvm_unreachable("getMemoryBufferForStream"); +} + + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getFile(const Twine &Filename, int64_t FileSize, + bool RequiresNullTerminator, bool IsVolatile) { + return getFileAux<MemoryBuffer>(Filename, FileSize, FileSize, 0, + RequiresNullTerminator, IsVolatile); +} + +template <typename MB> +static ErrorOr<std::unique_ptr<MB>> +getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, + uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, + bool IsVolatile); + +template <typename MB> +static ErrorOr<std::unique_ptr<MB>> +getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, + uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile) { + llvm_unreachable("getFileAux"); +} + +ErrorOr<std::unique_ptr<WritableMemoryBuffer>> +WritableMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize, + bool IsVolatile) { + return getFileAux<WritableMemoryBuffer>(Filename, FileSize, FileSize, 0, + /*RequiresNullTerminator*/ false, + IsVolatile); +} + +ErrorOr<std::unique_ptr<WritableMemoryBuffer>> +WritableMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize, + uint64_t Offset, bool IsVolatile) { + return getFileAux<WritableMemoryBuffer>(Filename, -1, MapSize, Offset, false, + IsVolatile); +} + +std::unique_ptr<WritableMemoryBuffer> +WritableMemoryBuffer::getNewUninitMemBuffer(size_t Size, const Twine &BufferName) { + using MemBuffer = MemoryBufferMem<WritableMemoryBuffer>; + // Allocate space for the MemoryBuffer, the data and the name. It is important + // that MemoryBuffer and data are aligned so PointerIntPair works with them. + // TODO: Is 16-byte alignment enough? We copy small object files with large + // alignment expectations into this buffer. + SmallString<256> NameBuf; + StringRef NameRef = BufferName.toStringRef(NameBuf); + size_t AlignedStringLen = alignTo(sizeof(MemBuffer) + NameRef.size() + 1, 16); + size_t RealLen = AlignedStringLen + Size + 1; + char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow)); + if (!Mem) + return nullptr; + + // The name is stored after the class itself. + CopyStringRef(Mem + sizeof(MemBuffer), NameRef); + + // The buffer begins after the name and must be aligned. + char *Buf = Mem + AlignedStringLen; + Buf[Size] = 0; // Null terminate buffer. + + auto *Ret = new (Mem) MemBuffer(StringRef(Buf, Size), true); + return std::unique_ptr<WritableMemoryBuffer>(Ret); +} + +std::unique_ptr<WritableMemoryBuffer> +WritableMemoryBuffer::getNewMemBuffer(size_t Size, const Twine &BufferName) { + auto SB = WritableMemoryBuffer::getNewUninitMemBuffer(Size, BufferName); + if (!SB) + return nullptr; + memset(SB->getBufferStart(), 0, Size); + return SB; +} + +static bool shouldUseMmap(sys::fs::file_t FD, + size_t FileSize, + size_t MapSize, + off_t Offset, + bool RequiresNullTerminator, + int PageSize, + bool IsVolatile) { + // XXX BINARYEn + return false; +} + +static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> +getReadWriteFile(const Twine &Filename, uint64_t FileSize, uint64_t MapSize, + uint64_t Offset) { + llvm_unreachable("getReadWriteFile"); +} + +ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> +WriteThroughMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize) { + return getReadWriteFile(Filename, FileSize, FileSize, 0); +} + +/// Map a subrange of the specified file as a WritableMemoryBuffer. +ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> +WriteThroughMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize, + uint64_t Offset) { + return getReadWriteFile(Filename, -1, MapSize, Offset); +} + +template <typename MB> +static ErrorOr<std::unique_ptr<MB>> +getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, + uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, + bool IsVolatile) { + llvm_unreachable("getOpenFileImpl"); +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getOpenFile(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, + bool RequiresNullTerminator, bool IsVolatile) { + return getOpenFileImpl<MemoryBuffer>(FD, Filename, FileSize, FileSize, 0, + RequiresNullTerminator, IsVolatile); +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getOpenFileSlice(sys::fs::file_t FD, const Twine &Filename, uint64_t MapSize, + int64_t Offset, bool IsVolatile) { + assert(MapSize != uint64_t(-1)); + return getOpenFileImpl<MemoryBuffer>(FD, Filename, -1, MapSize, Offset, false, + IsVolatile); +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> MemoryBuffer::getSTDIN() { + llvm_unreachable("getSTDIN"); +} + +ErrorOr<std::unique_ptr<MemoryBuffer>> +MemoryBuffer::getFileAsStream(const Twine &Filename) { + llvm_unreachable("getFileAsStream"); +} + +MemoryBufferRef MemoryBuffer::getMemBufferRef() const { + StringRef Data = getBuffer(); + StringRef Identifier = getBufferIdentifier(); + return MemoryBufferRef(Data, Identifier); +} + +SmallVectorMemoryBuffer::~SmallVectorMemoryBuffer() {} |