[PATCH 05/10] monitor/hmp: add CPUClass::get_pc fallback for HMP $pc

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Some targets, including x86, have no GDB register named "pc" (x86
uses eip/rip). When the GDB register lookup fails for "$pc" in
HMP expressions, fall back to CPUClass::get_pc so that "p $pc",
"x $pc" etc. work without relying on the legacy MonitorDef table.

This prepares for the eventual removal of MonitorDef while making
$pc available immediately for all targets that implement get_pc.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 monitor/hmp.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/monitor/hmp.c b/monitor/hmp.c
index 10e19e417aba..0a74247ca66a 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -402,7 +402,7 @@ void hmp_help_cmd(MonitorHMP *mon, const char *name)
  * Set @pval to the value in the register identified by @name.
  * return %true if the register is found, %false otherwise.
  */
-static bool gdb_get_register(MonitorHMP *hmp, int64_t *pval, const char *name)
+static bool get_register(MonitorHMP *hmp, int64_t *pval, const char *name)
 {
     g_autoptr(GArray) regs = NULL;
     CPUState *cs = monitor_hmp_get_cpu(hmp);
@@ -435,6 +435,10 @@ static bool gdb_get_register(MonitorHMP *hmp, int64_t *pval, const char *name)
         }
         return true;
     }
+    if (!strcmp(name, "pc") && cs->cc->get_pc) {
+        *pval = cs->cc->get_pc(cs);
+        return true;
+    }
     return false;
 }
 
@@ -526,7 +530,7 @@ static int64_t expr_unary(MonitorHMP *mon)
                 pch++;
             }
             *q = 0;
-            if (!gdb_get_register(mon, &reg, buf)
+            if (!get_register(mon, &reg, buf)
                 && get_monitor_def(mon, &reg, buf) < 0) {
                 expr_error(mon, "unknown register");
             }

-- 
2.55.0.543.g5ebe2ebe4ea8