Created hook at VM code fetch. It's for debugger

include/mrbconf.h

@@ -50,6 +50,7 @@
 //#define DISABLE_TIME		/* Time class */
 //#define DISABLE_STRUCT	/* Struct class */
 //#define DISABLE_STDIO		/* use of stdio */
+//#define DISABLE_DEBUG   /* hooks for debugger */
 
 /* Now DISABLE_GEMS is added as a command line flag in Rakefile, */
 /* we do not need to set it here. */
@@ -118,6 +119,9 @@ typedef short mrb_sym;
 #ifndef DISABLE_STDIO
 #define ENABLE_STDIO
 #endif
+#ifndef DISABLE_DEBUG
+#define ENABLE_DEBUG
+#endif
 
 #ifndef FALSE
 # define FALSE 0

include/mruby.h

@@ -133,6 +133,10 @@ typedef struct mrb_state {
   struct RNode *local_svar;/* regexp */
 #endif
 
+#ifdef ENABLE_DEBUG
+  void (*hook_vm_fetch_code)(struct mrb_state* mrb, struct mrb_irep *irep, mrb_code *pc, mrb_value *regs);
+#endif
+
   struct RClass *eException_class;
   struct RClass *eStandardError_class;
 

src/vm.c

@@ -480,13 +480,19 @@ argnum_error(mrb_state *mrb, int num)
   mrb->exc = (struct RObject*)mrb_object(exc);
 }
 
+#ifdef ENABLE_DEBUG
+#define HOOK_MRB_VM_FETCH_CODE(mrb, irep, pc, regs) ((mrb)->hook_vm_fetch_code ? (mrb)->hook_vm_fetch_code((mrb), (irep), (pc), (regs)) : NULL)
+#else
+#define HOOK_MRB_VM_FETCH_CODE(mrb, irep, pc, regs)
+#endif
+
 #ifdef __GNUC__
 #define DIRECT_THREADED
 #endif
 
 #ifndef DIRECT_THREADED
 
-#define INIT_DISPATCH for (;;) { i = *pc; switch (GET_OPCODE(i)) {
+#define INIT_DISPATCH for (;;) { i = *pc; HOOK_MRB_VM_FETCH_CODE(mrb, irep, pc, regs); switch (GET_OPCODE(i)) {
 #define CASE(op) case op:
 #define NEXT pc++; break
 #define JUMP break
@@ -496,8 +502,8 @@ argnum_error(mrb_state *mrb, int num)
 
 #define INIT_DISPATCH JUMP; return mrb_nil_value();
 #define CASE(op) L_ ## op:
-#define NEXT i=*++pc; goto *optable[GET_OPCODE(i)]
-#define JUMP i=*pc; goto *optable[GET_OPCODE(i)]
+#define NEXT i=*++pc; HOOK_MRB_VM_FETCH_CODE(mrb, irep, pc, regs); goto *optable[GET_OPCODE(i)]
+#define JUMP i=*pc; HOOK_MRB_VM_FETCH_CODE(mrb, irep, pc, regs); goto *optable[GET_OPCODE(i)]
 
 #define END_DISPATCH