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Make sure DataBufferLLVM contents are writable

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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
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22
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
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@@ -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(