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

1 files changed, 3 insertions, 7 deletions

diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
index 72b1b15f08f..77bfa7fe0a6 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -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());