[lldb] Refactor DataBuffer so we can map files as read-only

Currently, all data buffers are assumed to be writable. This is a
problem on macOS where it's not allowed to load unsigned binaries in
memory as writable. To be more precise, MAP_RESILIENT_CODESIGN and
MAP_RESILIENT_MEDIA need to be set for mapped (unsigned) binaries on our
platform.

Binaries are mapped through FileSystem::CreateDataBuffer which returns a
DataBufferLLVM. The latter is backed by a llvm::WritableMemoryBuffer
because every DataBuffer in LLDB is considered to be writable. In order
to use a read-only llvm::MemoryBuffer I had to split our abstraction
around it.

This patch distinguishes between a DataBuffer (read-only) and
WritableDataBuffer (read-write) and updates LLDB to use the appropriate
one.

rdar://74890607

Differential revision: https://reviews.llvm.org/D122856

1 files changed, 1 insertions, 1 deletions

diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp
index 381a41e..b7b28bc 100644
--- a/lldb/source/Commands/CommandObjectMemory.cpp
+++ b/lldb/source/Commands/CommandObjectMemory.cpp
@@ -639,7 +639,7 @@ protected:
       return false;
     }
 
-    DataBufferSP data_sp;
+    WritableDataBufferSP data_sp;
     size_t bytes_read = 0;
     if (compiler_type.GetOpaqueQualType()) {
       // Make sure we don't display our type as ASCII bytes like the default