target/hppa: Speed up hppa_is_pa20()

Although the hppa_is_pa20() helper is costly due to string comparisons
in object_dynamic_cast(), it is called quite often during memory lookups
and at each start of a block of instruction translations.
Speed hppa_is_pa20() up by calling object_dynamic_cast() only once at
CPU creation and store the result in the is_pa20 of struct CPUArchState.

Signed-off-by: Helge Deller <[email protected]>
Co-developed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>

Author: hdeller

target/hppa/cpu.c

@@ -193,6 +193,13 @@ static void hppa_cpu_realizefn(DeviceState *dev, Error **errp)
     tcg_cflags_set(cs, CF_PCREL);
 }
 
+static void hppa_cpu_initfn(Object *obj)
+{
+    CPUHPPAState *env = cpu_env(CPU(obj));
+
+    env->is_pa20 = !!object_dynamic_cast(obj, TYPE_HPPA64_CPU);
+}
+
 static void hppa_cpu_reset_hold(Object *obj, ResetType type)
 {
     HPPACPUClass *scc = HPPA_CPU_GET_CLASS(obj);
@@ -282,6 +289,7 @@ static const TypeInfo hppa_cpu_type_infos[] = {
         .parent = TYPE_CPU,
         .instance_size = sizeof(HPPACPU),
         .instance_align = __alignof(HPPACPU),
+        .instance_init = hppa_cpu_initfn,
         .abstract = false,
         .class_size = sizeof(HPPACPUClass),
         .class_init = hppa_cpu_class_init,

target/hppa/cpu.h

@@ -266,6 +266,8 @@ typedef struct CPUArchState {
 
     /* Fields up to this point are cleared by a CPU reset */
     struct {} end_reset_fields;
+
+    bool is_pa20;
 } CPUHPPAState;
 
 /**
@@ -297,9 +299,9 @@ struct HPPACPUClass {
 
 #include "exec/cpu-all.h"
 
-static inline bool hppa_is_pa20(CPUHPPAState *env)
+static inline bool hppa_is_pa20(const CPUHPPAState *env)
 {
-    return object_dynamic_cast(OBJECT(env_cpu(env)), TYPE_HPPA64_CPU) != NULL;
+    return env->is_pa20;
 }
 
 static inline int HPPA_BTLB_ENTRIES(CPUHPPAState *env)