vm: Add rudimentary bytecode execution tracing capability.

py/bc.h

@@ -13,6 +13,7 @@ typedef struct _mp_exc_stack {
 mp_vm_return_kind_t mp_execute_byte_code(const byte *code, const mp_obj_t *args, uint n_args, const mp_obj_t *args2, uint n_args2, mp_obj_t *ret);
 mp_vm_return_kind_t mp_execute_byte_code_2(const byte *code_info, const byte **ip_in_out, mp_obj_t *fastn, mp_obj_t **sp_in_out, mp_exc_stack_t *exc_stack, mp_exc_stack_t **exc_sp_in_out, volatile mp_obj_t inject_exc);
 void mp_byte_code_print(const byte *code, int len);
+void mp_byte_code_print2(const byte *code, int len);
 
 // Helper macros to access pointer with least significant bit holding a flag
 #define MP_TAGPTR_PTR(x) ((void*)((machine_uint_t)(x) & ~((machine_uint_t)1)))

py/showbc.c

@@ -28,6 +28,8 @@
     ip += sizeof(machine_uint_t); \
 } while (0)
 
+void mp_byte_code_print2(const byte *ip, int len);
+
 void mp_byte_code_print(const byte *ip, int len) {
     const byte *ip_start = ip;
 
@@ -71,7 +73,11 @@ void mp_byte_code_print(const byte *ip, int len) {
             printf("  bc=" INT_FMT " line=" UINT_FMT "\n", bc, source_line);
         }
     }
+    mp_byte_code_print2(ip, len - 0);
+}
 
+void mp_byte_code_print2(const byte *ip, int len) {
+    const byte *ip_start = ip;
     machine_uint_t unum;
     qstr qstr;
     while (ip - ip_start < len) {

py/vm.c

@@ -14,6 +14,11 @@
 #include "objgenerator.h"
 
 #define DETECT_VM_STACK_OVERFLOW (0)
+#if 0
+#define TRACE(ip) mp_byte_code_print2(ip, 1);
+#else
+#define TRACE(ip)
+#endif
 
 // Value stack grows up (this makes it incompatible with native C stack, but
 // makes sure that arguments to functions are in natural order arg1..argN
@@ -168,6 +173,7 @@ mp_vm_return_kind_t mp_execute_byte_code_2(const byte *code_info, const byte **i
 #if MICROPY_USE_COMPUTED_GOTO
     #include "vmentrytable.h"
     #define DISPATCH() do { \
+        TRACE(ip); \
         save_ip = ip; \
         op = *ip++; \
         goto *entry_table[op]; \
@@ -223,6 +229,7 @@ dispatch_loop:
 #if MICROPY_USE_COMPUTED_GOTO
                 DISPATCH();
 #else
+                TRACE(ip);
                 save_ip = ip;
                 op = *ip++;