Add support for FreeBSD arm live debugging

[emaste]

Summary

Fix RegisterContextPOSIX_arm::GetReisterSet
The target trip should be 'arm' not 'aarch64'

Add sw brkpt insn to PlatformFreeBSD::GetSoftwareBreakpointTrapOpcode

[omjavaid]

Its easier to review full context diffs. Please generate it using (git diff -U999999 or svn diff --diff-cmd=diff -x -U999999)

source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp

347 ↗

(On Diff #24159)

Please add case for arm in alphabetical order before ppc.

Also add a TODO to handle both (little/big endian) arm and thumb mode trap codes.

[trixirt]

Handle thumb breakpoints
Detect when in thumb code and silently disable breakpoints
FreeBSD does not support thumb breakpoints.
Define a reasonable breakpoint instruction to enable when thumb breakpoints are supported

[emaste]

Seems I didn't get any email notification from Phabricator for this :(
I will extract the thumb part and apply it.

source/Plugins/Process/POSIX/POSIXThread.cpp

179 ↗

(On Diff #24867)

Whitespace issue?

[emaste]

Extract thumb opcode stub from original change and sync whitespace etc. with PlatformLinux.cpp

[trixirt]

Thanks!

There is also a change to support core file reading, that I believe is
ready.
http://reviews.llvm.org/D9292

Tom

lldb/trunk/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp

 #include <stdio.h>
 #ifndef LLDB_DISABLE_POSIX
 #include <sys/utsname.h>
 #endif
 
 // C++ Includes
 // Other libraries and framework includes
 // Project includes
+#include "lldb/Breakpoint/BreakpointLocation.h"
 #include "lldb/Breakpoint/BreakpointSite.h"
 #include "lldb/Core/Error.h"
 #include "lldb/Core/Debugger.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
default:
         break;
     case llvm::Triple::aarch64:
         {
             static const uint8_t g_aarch64_opcode[] = { 0x00, 0x00, 0x20, 0xd4 };
             trap_opcode = g_aarch64_opcode;
             trap_opcode_size = sizeof(g_aarch64_opcode);
         }
         break;
+    // TODO: support big-endian arm and thumb trap codes.
     case llvm::Triple::arm:
         {
-            static const uint8_t g_arm_opcode[] = { 0xfe, 0xde, 0xff, 0xe7 };
-            trap_opcode = g_arm_opcode;
-            trap_opcode_size = sizeof(g_arm_opcode);
+            static const uint8_t g_arm_breakpoint_opcode[] = { 0xfe, 0xde, 0xff, 0xe7 };
+            static const uint8_t g_thumb_breakpoint_opcode[] = { 0x01, 0xde };
+
+            lldb::BreakpointLocationSP bp_loc_sp (bp_site->GetOwnerAtIndex (0));
+            AddressClass addr_class = eAddressClassUnknown;
+
+            if (bp_loc_sp)
+                addr_class = bp_loc_sp->GetAddress ().GetAddressClass ();
+
+            if (addr_class == eAddressClassCodeAlternateISA
+                || (addr_class == eAddressClassUnknown && (bp_site->GetLoadAddress() & 1)))
+            {
+                // TODO: Enable when FreeBSD supports thumb breakpoints.
+                // FreeBSD kernel as of 10.x, does not support thumb breakpoints
+                trap_opcode = g_thumb_breakpoint_opcode;
+                trap_opcode_size = 0;
+            }
+            else
+            {
+                trap_opcode = g_arm_breakpoint_opcode;
+                trap_opcode_size = sizeof(g_arm_breakpoint_opcode);
+            }
         }
         break;
     case llvm::Triple::mips64:
         {
             static const uint8_t g_hex_opcode[] = { 0x00, 0x00, 0x00, 0x0d };
             trap_opcode = g_hex_opcode;
             trap_opcode_size = sizeof(g_hex_opcode);
         }