New trap handler ABI (v4)

Replace the stop reasons ttmp11.trap_raised and ttmp11.excp_raised
with ttmp11.wave_stopped which indicates that the trap handler has
halted the wave as the result of an event (trap, single-step or
exception).

If the wave is stopped because of a trap, also record the trap_id in
ttmp11.saved_trap_id[7:0].

Save status.halt in ttmp11.saved_status_halt, so that it can be
restored when resuming a wave (changing a wave's state from stopped to
running or single-stepping).

Change-Id: I7322f59b60e8cc1b92bf5f067dba606a3109ef49

runtime/hsa-runtime/loader/executable.cpp

@@ -76,7 +76,8 @@ __attribute__((noinline)) static void _loader_debug_state() {
 // 1: Initial debug protocol
 // 2: New trap handler ABI. The reason for halting a wave is recorded in ttmp11[8:7].
 // 3: New trap handler ABI. A wave halted at S_ENDPGM rewinds its PC by 8 bytes, and sets ttmp11[9]=1.
-HSA_API r_debug _amdgpu_r_debug = {3,
+// 4: New trap handler ABI. Save the trap id in ttmp11[16:9]
+HSA_API r_debug _amdgpu_r_debug = {4,
                            nullptr,
                            reinterpret_cast<uintptr_t>(&_loader_debug_state),
                            r_debug::RT_CONSISTENT,