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Make sure DataBufferLLVM contents are writable 

Summary:
We sometimes need to write to the object file we've mapped into memory,
generally to apply relocations to debug info sections. We've had that
ability before, but with the introduction of DataBufferLLVM, we have
lost it, as the underlying llvm class (MemoryBuffer) only supports
read-only mappings.

This switches DataBufferLLVM to use the new llvm::WritableMemoryBuffer
class as a back-end, as this one guarantees to return a writable buffer.

This removes the need for the "Private" flag to the DataBufferLLVM
creation functions, as it was really used to mean "writable". The LLVM
function also does not have the NullTerminate flag, so I've modified our
clients to not require this feature and removed that flag as well.

Reviewers: zturner, clayborg, jingham

Subscribers: emaste, aprantl, arichardson, krytarowski, lldb-commits

Differential Revision: https://reviews.llvm.org/D40079

llvm-svn: 321255
This commit is contained in:
Pavel Labath 2017-12-21 10:54:30 +00:00
parent 4e945b6d05
commit 50251fc715
12 changed files with 61 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lldb/include/lldb/Interpreter/OptionValueFileSpec.h
View File

@ -77,7 +77,7 @@ public:
void SetDefaultValue(const FileSpec &value) { m_default_value = value; }
const lldb::DataBufferSP &GetFileContents(bool null_terminate);
const lldb::DataBufferSP &GetFileContents();
void SetCompletionMask(uint32_t mask) { m_completion_mask = mask; }

3
lldb/include/lldb/Symbol/ObjectFile.h
View File

@ -879,6 +879,9 @@ protected:
ConstString GetNextSyntheticSymbolName();
static lldb::DataBufferSP MapFileData(const FileSpec &file, uint64_t Size,
uint64_t Offset);
private:
DISALLOW_COPY_AND_ASSIGN(ObjectFile);
};

2
lldb/include/lldb/Target/Target.h
View File

@ -161,7 +161,7 @@ public:
lldb::LanguageType GetLanguage() const;
const char *GetExpressionPrefixContentsAsCString();
llvm::StringRef GetExpressionPrefixContents();
bool GetUseHexImmediates() const;

11
lldb/include/lldb/Utility/DataBufferLLVM.h
View File

@ -17,7 +17,7 @@
#include <stdint.h> // for uint8_t, uint64_t
namespace llvm {
class MemoryBuffer;
class WritableMemoryBuffer;
class Twine;
}
@ -28,10 +28,10 @@ public:
~DataBufferLLVM();
static std::shared_ptr<DataBufferLLVM>
CreateSliceFromPath(const llvm::Twine &Path, uint64_t Size, uint64_t Offset, bool Private = false);
CreateSliceFromPath(const llvm::Twine &Path, uint64_t Size, uint64_t Offset);
static std::shared_ptr<DataBufferLLVM>
CreateFromPath(const llvm::Twine &Path, bool NullTerminate = false, bool Private = false);
CreateFromPath(const llvm::Twine &Path);
uint8_t *GetBytes() override;
const uint8_t *GetBytes() const override;
@ -42,10 +42,9 @@ public:
private:
/// \brief Construct a DataBufferLLVM from \p Buffer. \p Buffer must be a
/// valid pointer.
explicit DataBufferLLVM(std::unique_ptr<llvm::MemoryBuffer> Buffer);
const uint8_t *GetBuffer() const;
explicit DataBufferLLVM(std::unique_ptr<llvm::WritableMemoryBuffer> Buffer);
std::unique_ptr<llvm::MemoryBuffer> Buffer;
std::unique_ptr<llvm::WritableMemoryBuffer> Buffer;
};
}

6
lldb/source/Interpreter/OptionValueFileSpec.cpp
View File

@ -113,14 +113,12 @@ size_t OptionValueFileSpec::AutoComplete(
return matches.GetSize();
}
const lldb::DataBufferSP &
OptionValueFileSpec::GetFileContents(bool null_terminate) {
const lldb::DataBufferSP &OptionValueFileSpec::GetFileContents() {
if (m_current_value) {
const auto file_mod_time = FileSystem::GetModificationTime(m_current_value);
if (m_data_sp && m_data_mod_time == file_mod_time)
return m_data_sp;
m_data_sp = DataBufferLLVM::CreateFromPath(m_current_value.GetPath(),
null_terminate);
m_data_sp = DataBufferLLVM::CreateFromPath(m_current_value.GetPath());
m_data_mod_time = file_mod_time;
}
return m_data_sp;

22
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
View File

@ -24,7 +24,6 @@
#include "lldb/Target/Target.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataBufferLLVM.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/Stream.h"
@ -406,8 +405,7 @@ ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
lldb::offset_t file_offset,
lldb::offset_t length) {
if (!data_sp) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset, true);
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
@ -424,8 +422,7 @@ ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset, true);
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
@ -684,8 +681,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
size_t section_header_end = header.e_shoff + header.e_shentsize;
if (header.HasHeaderExtension() &&
section_header_end > data_sp->GetByteSize()) {
data_sp = DataBufferLLVM::CreateSliceFromPath(
file.GetPath(), section_header_end, file_offset);
data_sp = MapFileData(file, section_header_end, file_offset);
if (data_sp) {
data.SetData(data_sp);
lldb::offset_t header_offset = data_offset;
@ -698,8 +694,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
section_header_end =
header.e_shoff + header.e_shnum * header.e_shentsize;
if (section_header_end > data_sp->GetByteSize()) {
data_sp = DataBufferLLVM::CreateSliceFromPath(
file.GetPath(), section_header_end, file_offset);
data_sp = MapFileData(file, section_header_end, file_offset);
if (data_sp)
data.SetData(data_sp);
}
@ -741,8 +736,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
size_t program_headers_end =
header.e_phoff + header.e_phnum * header.e_phentsize;
if (program_headers_end > data_sp->GetByteSize()) {
data_sp = DataBufferLLVM::CreateSliceFromPath(
file.GetPath(), program_headers_end, file_offset);
data_sp = MapFileData(file, program_headers_end, file_offset);
if (data_sp)
data.SetData(data_sp);
}
@ -757,8 +751,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
}
if (segment_data_end > data_sp->GetByteSize()) {
data_sp = DataBufferLLVM::CreateSliceFromPath(
file.GetPath(), segment_data_end, file_offset);
data_sp = MapFileData(file, segment_data_end, file_offset);
if (data_sp)
data.SetData(data_sp);
}
@ -767,8 +760,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
CalculateELFNotesSegmentsCRC32(program_headers, data);
} else {
// Need to map entire file into memory to calculate the crc.
data_sp = DataBufferLLVM::CreateSliceFromPath(file.GetPath(), -1,
file_offset);
data_sp = MapFileData(file, -1, file_offset);
if (data_sp) {
data.SetData(data_sp);
gnu_debuglink_crc = calc_gnu_debuglink_crc32(

36
lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
View File

@ -38,7 +38,7 @@
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadList.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataBufferLLVM.h"
#include "lldb/Utility/DataBuffer.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Status.h"
@ -862,8 +862,7 @@ ObjectFile *ObjectFileMachO::CreateInstance(const lldb::ModuleSP &module_sp,
lldb::offset_t file_offset,
lldb::offset_t length) {
if (!data_sp) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
@ -874,8 +873,7 @@ ObjectFile *ObjectFileMachO::CreateInstance(const lldb::ModuleSP &module_sp,
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
@ -914,8 +912,7 @@ size_t ObjectFileMachO::GetModuleSpecifications(
size_t header_and_load_cmds =
header.sizeofcmds + MachHeaderSizeFromMagic(header.magic);
if (header_and_load_cmds >= data_sp->GetByteSize()) {
data_sp = DataBufferLLVM::CreateSliceFromPath(
file.GetPath(), header_and_load_cmds, file_offset);
data_sp = MapFileData(file, header_and_load_cmds, file_offset);
data.SetData(data_sp);
data_offset = MachHeaderSizeFromMagic(header.magic);
}
@ -1127,8 +1124,7 @@ bool ObjectFileMachO::ParseHeader() {
ReadMemory(process_sp, m_memory_addr, header_and_lc_size);
} else {
// Read in all only the load command data from the file on disk
data_sp = DataBufferLLVM::CreateSliceFromPath(
m_file.GetPath(), header_and_lc_size, m_file_offset);
data_sp = MapFileData(m_file, header_and_lc_size, m_file_offset);
if (data_sp->GetByteSize() != header_and_lc_size)
return false;
}
@ -2100,9 +2096,8 @@ UUID ObjectFileMachO::GetSharedCacheUUID(FileSpec dyld_shared_cache,
const ByteOrder byte_order,
const uint32_t addr_byte_size) {
UUID dsc_uuid;
DataBufferSP DscData = DataBufferLLVM::CreateSliceFromPath(
dyld_shared_cache.GetPath(),
sizeof(struct lldb_copy_dyld_cache_header_v1), 0);
DataBufferSP DscData = MapFileData(
dyld_shared_cache, sizeof(struct lldb_copy_dyld_cache_header_v1), 0);
if (!DscData)
return dsc_uuid;
DataExtractor dsc_header_data(DscData, byte_order, addr_byte_size);
@ -2708,9 +2703,8 @@ size_t ObjectFileMachO::ParseSymtab() {
// Process the dyld shared cache header to find the unmapped symbols
DataBufferSP dsc_data_sp = DataBufferLLVM::CreateSliceFromPath(
dsc_filespec.GetPath(), sizeof(struct lldb_copy_dyld_cache_header_v1),
0);
DataBufferSP dsc_data_sp = MapFileData(
dsc_filespec, sizeof(struct lldb_copy_dyld_cache_header_v1), 0);
if (!dsc_uuid.IsValid()) {
dsc_uuid = GetSharedCacheUUID(dsc_filespec, byte_order, addr_byte_size);
}
@ -2742,11 +2736,9 @@ size_t ObjectFileMachO::ParseSymtab() {
if (uuid_match &&
mappingOffset >= sizeof(struct lldb_copy_dyld_cache_header_v1)) {
DataBufferSP dsc_mapping_info_data_sp =
DataBufferLLVM::CreateSliceFromPath(
dsc_filespec.GetPath(),
sizeof(struct lldb_copy_dyld_cache_mapping_info),
mappingOffset);
DataBufferSP dsc_mapping_info_data_sp = MapFileData(
dsc_filespec, sizeof(struct lldb_copy_dyld_cache_mapping_info),
mappingOffset);
DataExtractor dsc_mapping_info_data(dsc_mapping_info_data_sp,
byte_order, addr_byte_size);
@ -2770,9 +2762,7 @@ size_t ObjectFileMachO::ParseSymtab() {
if (localSymbolsOffset && localSymbolsSize) {
// Map the local symbols
DataBufferSP dsc_local_symbols_data_sp =
DataBufferLLVM::CreateSliceFromPath(dsc_filespec.GetPath(),
localSymbolsSize,
localSymbolsOffset);
MapFileData(dsc_filespec, localSymbolsSize, localSymbolsOffset);
if (dsc_local_symbols_data_sp) {
DataExtractor dsc_local_symbols_data(dsc_local_symbols_data_sp,

10
lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
View File

@ -22,7 +22,6 @@
#include "lldb/Target/Target.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataBufferLLVM.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/StreamString.h"
#include "lldb/Utility/Timer.h"
@ -66,8 +65,7 @@ ObjectFile *ObjectFilePECOFF::CreateInstance(const lldb::ModuleSP &module_sp,
lldb::offset_t file_offset,
lldb::offset_t length) {
if (!data_sp) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
data_sp = MapFileData(file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
@ -78,8 +76,7 @@ ObjectFile *ObjectFilePECOFF::CreateInstance(const lldb::ModuleSP &module_sp,
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length) {
data_sp =
DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
data_sp = MapFileData(file, length, file_offset);
if (!data_sp)
return nullptr;
}
@ -436,8 +433,7 @@ DataExtractor ObjectFilePECOFF::ReadImageData(uint32_t offset, size_t size) {
if (m_file) {
// A bit of a hack, but we intend to write to this buffer, so we can't
// mmap it.
auto buffer_sp =
DataBufferLLVM::CreateSliceFromPath(m_file.GetPath(), size, offset, true);
auto buffer_sp = MapFileData(m_file, size, offset);
return DataExtractor(buffer_sp, GetByteOrder(), GetAddressByteSize());
}
ProcessSP process_sp(m_process_wp.lock());

2
lldb/source/Plugins/Platform/MacOSX/PlatformDarwin.cpp
View File

@ -1173,7 +1173,7 @@ const char *PlatformDarwin::GetDeveloperDirectory() {
xcode_dir_path.append("/usr/share/xcode-select/xcode_dir_path");
temp_file_spec.SetFile(xcode_dir_path, false);
auto dir_buffer =
DataBufferLLVM::CreateFromPath(temp_file_spec.GetPath(), true);
DataBufferLLVM::CreateFromPath(temp_file_spec.GetPath());
if (dir_buffer && dir_buffer->GetByteSize() > 0) {
llvm::StringRef path_ref(dir_buffer->GetChars());
// Trim tailing newlines and make sure there is enough room for a null

5
lldb/source/Symbol/ObjectFile.cpp
View File

@ -688,3 +688,8 @@ Status ObjectFile::LoadInMemory(Target &target, bool set_pc) {
void ObjectFile::RelocateSection(lldb_private::Section *section)
{
}
DataBufferSP ObjectFile::MapFileData(const FileSpec &file, uint64_t Size,
uint64_t Offset) {
return DataBufferLLVM::CreateSliceFromPath(file.GetPath(), Size, Offset);
}

13
lldb/source/Target/Target.cpp
View File

@ -2313,7 +2313,7 @@ ExpressionResults Target::EvaluateExpression(
result_valobj_sp = persistent_var_sp->GetValueObject();
execution_results = eExpressionCompleted;
} else {
const char *prefix = GetExpressionPrefixContentsAsCString();
llvm::StringRef prefix = GetExpressionPrefixContents();
Status error;
execution_results = UserExpression::Evaluate(exe_ctx, options, expr, prefix,
result_valobj_sp, error,
@ -4046,18 +4046,19 @@ LanguageType TargetProperties::GetLanguage() const {
return LanguageType();
}
const char *TargetProperties::GetExpressionPrefixContentsAsCString() {
llvm::StringRef TargetProperties::GetExpressionPrefixContents() {
const uint32_t idx = ePropertyExprPrefix;
OptionValueFileSpec *file =
m_collection_sp->GetPropertyAtIndexAsOptionValueFileSpec(nullptr, false,
idx);
if (file) {
const bool null_terminate = true;
DataBufferSP data_sp(file->GetFileContents(null_terminate));
DataBufferSP data_sp(file->GetFileContents());
if (data_sp)
return (const char *)data_sp->GetBytes();
return llvm::StringRef(
reinterpret_cast<const char *>(data_sp->GetBytes()),
data_sp->GetByteSize());
}
return nullptr;
return "";
}
bool TargetProperties::GetBreakpointsConsultPlatformAvoidList() {

28
lldb/source/Utility/DataBufferLLVM.cpp
View File

@ -18,7 +18,8 @@
using namespace lldb_private;
DataBufferLLVM::DataBufferLLVM(std::unique_ptr<llvm::MemoryBuffer> MemBuffer)
DataBufferLLVM::DataBufferLLVM(
std::unique_ptr<llvm::WritableMemoryBuffer> MemBuffer)
: Buffer(std::move(MemBuffer)) {
assert(Buffer != nullptr &&
"Cannot construct a DataBufferLLVM with a null buffer");
@ -28,13 +29,13 @@ DataBufferLLVM::~DataBufferLLVM() {}
std::shared_ptr<DataBufferLLVM>
DataBufferLLVM::CreateSliceFromPath(const llvm::Twine &Path, uint64_t Size,
uint64_t Offset, bool Private) {
uint64_t Offset) {
// If the file resides non-locally, pass the volatile flag so that we don't
// mmap it.
if (!Private)
Private = !llvm::sys::fs::is_local(Path);
bool IsVolatile = !llvm::sys::fs::is_local(Path);
auto Buffer = llvm::MemoryBuffer::getFileSlice(Path, Size, Offset, Private);
auto Buffer =
llvm::WritableMemoryBuffer::getFileSlice(Path, Size, Offset, IsVolatile);
if (!Buffer)
return nullptr;
return std::shared_ptr<DataBufferLLVM>(
@ -42,13 +43,12 @@ DataBufferLLVM::CreateSliceFromPath(const llvm::Twine &Path, uint64_t Size,
}
std::shared_ptr<DataBufferLLVM>
DataBufferLLVM::CreateFromPath(const llvm::Twine &Path, bool NullTerminate, bool Private) {
DataBufferLLVM::CreateFromPath(const llvm::Twine &Path) {
// If the file resides non-locally, pass the volatile flag so that we don't
// mmap it.
if (!Private)
Private = !llvm::sys::fs::is_local(Path);
bool IsVolatile = !llvm::sys::fs::is_local(Path);
auto Buffer = llvm::MemoryBuffer::getFile(Path, -1, NullTerminate, Private);
auto Buffer = llvm::WritableMemoryBuffer::getFile(Path, -1, IsVolatile);
if (!Buffer)
return nullptr;
return std::shared_ptr<DataBufferLLVM>(
@ -56,15 +56,13 @@ DataBufferLLVM::CreateFromPath(const llvm::Twine &Path, bool NullTerminate, bool
}
uint8_t *DataBufferLLVM::GetBytes() {
return const_cast<uint8_t *>(GetBuffer());
return reinterpret_cast<uint8_t *>(Buffer->getBufferStart());
}
const uint8_t *DataBufferLLVM::GetBytes() const { return GetBuffer(); }
const uint8_t *DataBufferLLVM::GetBytes() const {
return reinterpret_cast<const uint8_t *>(Buffer->getBufferStart());
}
lldb::offset_t DataBufferLLVM::GetByteSize() const {
return Buffer->getBufferSize();
}
const uint8_t *DataBufferLLVM::GetBuffer() const {
return reinterpret_cast<const uint8_t *>(Buffer->getBufferStart());
}