Read and write a LC_NOTE "addrable bits" for addressing mask

This patch adds code to process save-core for Mach-O files which
embeds an "addrable bits" LC_NOTE when the process is using a
code address mask (e.g. AArch64 v8.3 with ptrauth aka arm64e).
Add code to ObjectFileMachO to read that LC_NOTE from corefiles,
and ProcessMachCore to set the process masks based on it when reading
a corefile back in.

Also have "process status --verbose" print the current address masks
that lldb is using internally to strip ptrauth bits off of addresses.

Differential Revision: https://reviews.llvm.org/D106348
rdar://68630113

1 files changed, 14 insertions, 0 deletions

diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index e4f67c0..00fb4d66 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -29,6 +29,8 @@
 #include "lldb/Utility/Args.h"
 #include "lldb/Utility/State.h"
 
+#include <bitset>
+
 using namespace lldb;
 using namespace lldb_private;
 
@@ -1341,6 +1343,18 @@ protected:
                              num_frames, num_frames_with_source, stop_format);
 
     if (m_options.m_verbose) {
+      addr_t code_mask = process->GetCodeAddressMask();
+      addr_t data_mask = process->GetDataAddressMask();
+      if (code_mask != 0) {
+        int bits = std::bitset<64>(~code_mask).count();
+        result.AppendMessageWithFormat(
+            "Addressable code address mask: 0x%" PRIx64 "\n", code_mask);
+        result.AppendMessageWithFormat(
+            "Addressable data address mask: 0x%" PRIx64 "\n", data_mask);
+        result.AppendMessageWithFormat(
+            "Number of bits used in addressing (code): %d\n", bits);
+      }
+
       PlatformSP platform_sp = process->GetTarget().GetPlatform();
       if (!platform_sp) {
         result.AppendError("Couldn'retrieve the target's platform");