caio/clang-p2996
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[lldb] Refactor DataBuffer so we can map files as read-only

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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
This commit is contained in:
Jonas Devlieghere
2022-04-01 15:59:18 -07:00
parent 4169650537
commit fc54427e76
80 changed files with 433 additions and 170 deletions
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11
lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
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@@ -2442,7 +2442,7 @@ bool RenderScriptRuntime::LoadAllocation(Stream &strm, const uint32_t alloc_id,
auto data_sp = FileSystem::Instance().CreateDataBuffer(file.GetPath());
// Cast start of buffer to FileHeader and use pointer to read metadata
void *file_buf = data_sp->GetBytes();
const void *file_buf = data_sp->GetBytes();
if (file_buf == nullptr ||
data_sp->GetByteSize() < (sizeof(AllocationDetails::FileHeader) +
sizeof(AllocationDetails::ElementHeader))) {
@@ -2451,7 +2451,7 @@ bool RenderScriptRuntime::LoadAllocation(Stream &strm, const uint32_t alloc_id,
return false;
}
const AllocationDetails::FileHeader *file_header =
static_cast<AllocationDetails::FileHeader *>(file_buf);
static_cast<const AllocationDetails::FileHeader *>(file_buf);
// Check file starts with ascii characters "RSAD"
if (memcmp(file_header->ident, "RSAD", 4)) {
@@ -2463,8 +2463,9 @@ bool RenderScriptRuntime::LoadAllocation(Stream &strm, const uint32_t alloc_id,
// Look at the type of the root element in the header
AllocationDetails::ElementHeader root_el_hdr;
memcpy(&root_el_hdr, static_cast<uint8_t *>(file_buf) +
sizeof(AllocationDetails::FileHeader),
memcpy(&root_el_hdr,
static_cast<const uint8_t *>(file_buf) +
sizeof(AllocationDetails::FileHeader),
sizeof(AllocationDetails::ElementHeader));
LLDB_LOGF(log, "%s - header type %" PRIu32 ", element size %" PRIu32,
@@ -2515,7 +2516,7 @@ bool RenderScriptRuntime::LoadAllocation(Stream &strm, const uint32_t alloc_id,
}
// Advance buffer past header
file_buf = static_cast<uint8_t *>(file_buf) + file_header->hdr_size;
file_buf = static_cast<const uint8_t *>(file_buf) + file_header->hdr_size;
// Calculate size of allocation data in file
size_t size = data_sp->GetByteSize() - file_header->hdr_size;