[lldb] When LLDB_ENABLE_MTE is ON always run the driver with MTE (#186322)

When LLDB_ENABLE_MTE is set to ON, we should always run the driver with
MTE by signing with the checked-allocations entitlement.

lldb/include/lldb/Host/Config.h.cmake

@@ -51,6 +51,8 @@
 
 #cmakedefine01 LLDB_ENABLE_TREESITTER
 
+#cmakedefine01 LLDB_ENABLE_MTE
+
 #cmakedefine LLDB_PYTHON_HOME R"(${LLDB_PYTHON_HOME})"
 
 #define LLDB_INSTALL_LIBDIR_BASENAME "${LLDB_INSTALL_LIBDIR_BASENAME}"

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp

@@ -25,6 +25,7 @@
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/ThreadedCommunication.h"
 #include "lldb/DataFormatters/TypeSummary.h"
+#include "lldb/Host/Config.h"
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/Pipe.h"
@@ -49,6 +50,7 @@
 #include <cstdlib>
 #include <memory>
 #include <optional>
+#include <stdlib.h>
 #include <string>
 
 using namespace lldb;
@@ -289,6 +291,13 @@ llvm::StringRef ScriptInterpreterPython::GetPluginDescriptionStatic() {
 }
 
 void ScriptInterpreterPython::Initialize() {
+#if LLDB_ENABLE_MTE
+  // Python's allocator (pymalloc) is not aware of Memory Tagging Extension
+  // (MTE) and crashes.
+  // https://bugs.python.org/issue43593
+  setenv("PYTHONMALLOC", "malloc", /*overwrite=*/true);
+#endif
+
   HostInfo::SetSharedLibraryDirectoryHelper(
       ScriptInterpreterPython::SharedLibraryDirectoryHelper);
   PluginManager::RegisterPlugin(

lldb/tools/driver/CMakeLists.txt

@@ -9,11 +9,23 @@ if(APPLE)
     )
   # Inline info plist in binary (use target_link_options for this as soon as CMake 3.13 is available)
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-sectcreate,__TEXT,__info_plist,${CMAKE_CURRENT_BINARY_DIR}/lldb-Info.plist")
+
+  if(LLDB_CODESIGN_IDENTITY)
+    set(LLVM_CODESIGNING_IDENTITY ${LLDB_CODESIGN_IDENTITY})
+  elseif(NOT LLVM_CODESIGNING_IDENTITY)
+    set(LLVM_CODESIGNING_IDENTITY "-")
+  endif()
+
+  # If we're building with assertions and LLDB_ENABLE_MTE is set to ON,
+  # build the driver to always run under MTE.
+  if (LLDB_ENABLE_MTE AND LLVM_ENABLE_ASSERTIONS)
+    set(ENTITLEMENTS ENTITLEMENTS ${CMAKE_CURRENT_SOURCE_DIR}/lldb-mte-entitlements.plist)
+  endif()
 endif()
 
 if (UNIX AND "${CMAKE_SYSTEM_NAME}" MATCHES "AIX")
-  remove_definitions("-D_XOPEN_SOURCE=700")                                    
-  add_definitions("-D_ALL_SOURCE")                                             
+  remove_definitions("-D_XOPEN_SOURCE=700")
+  add_definitions("-D_ALL_SOURCE")
 endif()
 
 set(LLDB_DRIVER_LINK_LIBS
@@ -30,6 +42,8 @@ add_lldb_tool(lldb
   Driver.cpp
   Platform.cpp
 
+  ${ENTITLEMENTS}
+
   LINK_COMPONENTS
     Option
     Support

lldb/tools/driver/lldb-mte-entitlements.plist

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.developer.hardened-process</key>
+	<true/>
+	<key>com.apple.developer.hardened-process.checked-allocations</key>
+	<true/>
+</dict>
+</plist>