Prohibit changes to iseq in principle

17 files changed, 65 insertions, 61 deletions

diff --git a/include/mruby.h b/include/mruby.h
index 55505a213..b1b983f52 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -127,8 +127,8 @@ typedef struct {
   uint16_t ridx;
   uint16_t epos;
   struct REnv *env;
-  mrb_code *pc;                 /* return address */
-  mrb_code *err;                /* error position */
+  const mrb_code *pc;           /* return address */
+  const mrb_code *err;          /* error position */
   int argc;
   int acc;
   struct RClass *target_class;
@@ -243,8 +243,8 @@ typedef struct mrb_state {
 #endif
 
 #ifdef MRB_ENABLE_DEBUG_HOOK
-  void (*code_fetch_hook)(struct mrb_state* mrb, struct mrb_irep *irep, mrb_code *pc, mrb_value *regs);
-  void (*debug_op_hook)(struct mrb_state* mrb, struct mrb_irep *irep, mrb_code *pc, mrb_value *regs);
+  void (*code_fetch_hook)(struct mrb_state* mrb, struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
+  void (*debug_op_hook)(struct mrb_state* mrb, struct mrb_irep *irep, const mrb_code *pc, mrb_value *regs);
 #endif
 
 #ifdef MRB_BYTECODE_DECODE_OPTION
@@ -1057,7 +1057,7 @@ MRB_API mrb_value mrb_top_self(mrb_state *);
 MRB_API mrb_value mrb_run(mrb_state*, struct RProc*, mrb_value);
 MRB_API mrb_value mrb_top_run(mrb_state*, struct RProc*, mrb_value, unsigned int);
 MRB_API mrb_value mrb_vm_run(mrb_state*, struct RProc*, mrb_value, unsigned int);
-MRB_API mrb_value mrb_vm_exec(mrb_state*, struct RProc*, mrb_code*);
+MRB_API mrb_value mrb_vm_exec(mrb_state*, struct RProc*, const mrb_code*);
 /* compatibility macros */
 #define mrb_toplevel_run_keep(m,p,k) mrb_top_run((m),(p),mrb_top_self(m),(k))
 #define mrb_toplevel_run(m,p) mrb_toplevel_run_keep((m),(p),0)
diff --git a/include/mruby/irep.h b/include/mruby/irep.h
index d42fd0fb8..2989e0647 100644
--- a/include/mruby/irep.h
+++ b/include/mruby/irep.h
@@ -32,7 +32,7 @@ typedef struct mrb_irep {
   uint16_t nregs;          /* Number of register variables */
   uint8_t flags;
 
-  mrb_code *iseq;
+  const mrb_code *iseq;
   mrb_value *pool;
   mrb_sym *syms;
   struct mrb_irep **reps;
@@ -80,7 +80,7 @@ struct mrb_insn_data {
   uint8_t c;
 };
 
-struct mrb_insn_data mrb_decode_insn(mrb_code *pc);
+struct mrb_insn_data mrb_decode_insn(const mrb_code *pc);
 
 MRB_END_DECL
 
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c b/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
index 513db4ded..530d824eb 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
@@ -428,7 +428,7 @@ mrb_debug_disable_break_all(mrb_state *mrb, mrb_debug_context *dbg)
 }
 
 static mrb_bool
-check_start_pc_for_line(mrb_state *mrb, mrb_irep *irep, mrb_code *pc, uint16_t line)
+check_start_pc_for_line(mrb_state *mrb, mrb_irep *irep, const mrb_code *pc, uint16_t line)
 {
   if (pc > irep->iseq) {
     if (line == mrb_debug_get_line(mrb, irep, pc - irep->iseq - 1)) {
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/apiprint.c b/mrbgems/mruby-bin-debugger/tools/mrdb/apiprint.c
index f888d1430..cdd7b6fa6 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/apiprint.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/apiprint.c
@@ -33,7 +33,7 @@ mrdb_check_syntax(mrb_state *mrb, mrb_debug_context *dbg, const char *expr, size
 mrb_value
 mrb_debug_eval(mrb_state *mrb, mrb_debug_context *dbg, const char *expr, size_t len, mrb_bool *exc, int direct_eval)
 {
-  void (*tmp)(struct mrb_state *, struct mrb_irep *, mrb_code *, mrb_value *);
+  void (*tmp)(struct mrb_state *, struct mrb_irep *, const mrb_code *, mrb_value *);
   mrb_value ruby_code;
   mrb_value s;
   mrb_value v;
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c
index 003406172..d2fa4c856 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c
@@ -505,7 +505,7 @@ get_and_parse_command(mrb_state *mrb, mrdb_state *mrdb)
 }
 
 static int32_t
-check_method_breakpoint(mrb_state *mrb, mrb_irep *irep, mrb_code *pc, mrb_value *regs)
+check_method_breakpoint(mrb_state *mrb, mrb_irep *irep, const mrb_code *pc, mrb_value *regs)
 {
   struct RClass* c;
   mrb_sym sym;
@@ -546,7 +546,7 @@ check_method_breakpoint(mrb_state *mrb, mrb_irep *irep, mrb_code *pc, mrb_value
 }
 
 static void
-mrb_code_fetch_hook(mrb_state *mrb, mrb_irep *irep, mrb_code *pc, mrb_value *regs)
+mrb_code_fetch_hook(mrb_state *mrb, mrb_irep *irep, const mrb_code *pc, mrb_value *regs)
 {
   const char *file;
   int32_t line;
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
index 7b14a899f..7c21de317 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
@@ -105,7 +105,7 @@ typedef struct mrb_debug_breakpoint {
 typedef struct mrb_debug_context {
   struct mrb_irep *root_irep;
   struct mrb_irep *irep;
-  mrb_code *pc;
+  const mrb_code *pc;
   mrb_value *regs;
 
   const char *prvfile;
diff --git a/mrbgems/mruby-compiler/core/codegen.c b/mrbgems/mruby-compiler/core/codegen.c
index f4dbe63a1..36367f656 100644
--- a/mrbgems/mruby-compiler/core/codegen.c
+++ b/mrbgems/mruby-compiler/core/codegen.c
@@ -291,7 +291,7 @@ on_eval(codegen_scope *s)
 }
 
 struct mrb_insn_data
-mrb_decode_insn(mrb_code *pc)
+mrb_decode_insn(const mrb_code *pc)
 {
   struct mrb_insn_data data = { 0 };
   mrb_code insn = READ_B();
diff --git a/mrbgems/mruby-eval/src/eval.c b/mrbgems/mruby-eval/src/eval.c
index e8f1d3e95..e2388f026 100644
--- a/mrbgems/mruby-eval/src/eval.c
+++ b/mrbgems/mruby-eval/src/eval.c
@@ -102,25 +102,28 @@ patch_irep(mrb_state *mrb, mrb_irep *irep, int bnest, mrb_irep *top)
   uint8_t c;
   mrb_code insn;
   int argc = irep_argc(irep);
+  mrb_code *iseq = (mrb_code *)irep->iseq;
+
+  mrb_assert((irep->flags & MRB_ISEQ_NO_FREE) == 0);
 
   for (i = 0; i < irep->ilen; ) {
-    insn = irep->iseq[i];
+    insn = iseq[i];
     switch(insn){
     case OP_EPUSH:
-      b = PEEK_S(irep->iseq+i+1);
+      b = PEEK_S(iseq+i+1);
       patch_irep(mrb, irep->reps[b], bnest + 1, top);
       break;
 
     case OP_LAMBDA:
     case OP_BLOCK:
-      a = PEEK_B(irep->iseq+i+1);
-      b = PEEK_B(irep->iseq+i+2);
+      a = PEEK_B(iseq+i+1);
+      b = PEEK_B(iseq+i+2);
       patch_irep(mrb, irep->reps[b], bnest + 1, top);
       break;
 
     case OP_SEND:
-      b = PEEK_B(irep->iseq+i+2);
-      c = PEEK_B(irep->iseq+i+3);
+      b = PEEK_B(iseq+i+2);
+      c = PEEK_B(iseq+i+3);
       if (c != 0) {
         break;
       }
@@ -128,24 +131,24 @@ patch_irep(mrb_state *mrb, mrb_irep *irep, int bnest, mrb_irep *top)
         uint16_t arg = search_variable(mrb, irep->syms[b], bnest);
         if (arg != 0) {
           /* must replace */
-          irep->iseq[i] = OP_GETUPVAR;
-          irep->iseq[i+2] = arg >> 8;
-          irep->iseq[i+3] = arg & 0xff;
+          iseq[i] = OP_GETUPVAR;
+          iseq[i+2] = arg >> 8;
+          iseq[i+3] = arg & 0xff;
         }
       }
       break;
 
     case OP_MOVE:
-      a = PEEK_B(irep->iseq+i+1);
-      b = PEEK_B(irep->iseq+i+2);
+      a = PEEK_B(iseq+i+1);
+      b = PEEK_B(iseq+i+2);
       /* src part */
       if (potential_upvar_p(irep->lv, b, argc, irep->nlocals)) {
         uint16_t arg = search_variable(mrb, irep->lv[b - 1].name, bnest);
         if (arg != 0) {
           /* must replace */
-          irep->iseq[i] = insn = OP_GETUPVAR;
-          irep->iseq[i+2] = arg >> 8;
-          irep->iseq[i+3] = arg & 0xff;
+          iseq[i] = insn = OP_GETUPVAR;
+          iseq[i+2] = arg >> 8;
+          iseq[i+3] = arg & 0xff;
         }
       }
       /* dst part */
@@ -153,18 +156,18 @@ patch_irep(mrb_state *mrb, mrb_irep *irep, int bnest, mrb_irep *top)
         uint16_t arg = search_variable(mrb, irep->lv[a - 1].name, bnest);
         if (arg != 0) {
           /* must replace */
-          irep->iseq[i] = insn = OP_SETUPVAR;
-          irep->iseq[i+1] = (mrb_code)b;
-          irep->iseq[i+2] = arg >> 8;
-          irep->iseq[i+3] = arg & 0xff;
+          iseq[i] = insn = OP_SETUPVAR;
+          iseq[i+1] = (mrb_code)b;
+          iseq[i+2] = arg >> 8;
+          iseq[i+3] = arg & 0xff;
         }
       }
       break;
 
     case OP_GETUPVAR:
-      a = PEEK_B(irep->iseq+i+1);
-      b = PEEK_B(irep->iseq+i+2);
-      c = PEEK_B(irep->iseq+i+3);
+      a = PEEK_B(iseq+i+1);
+      b = PEEK_B(iseq+i+2);
+      c = PEEK_B(iseq+i+3);
       {
         int lev = c+1;
         mrb_irep *tmp = search_irep(top, bnest, lev, irep);
@@ -172,18 +175,18 @@ patch_irep(mrb_state *mrb, mrb_irep *irep, int bnest, mrb_irep *top)
           uint16_t arg = search_variable(mrb, tmp->lv[b-1].name, bnest);
           if (arg != 0) {
             /* must replace */
-            irep->iseq[i] = OP_GETUPVAR;
-            irep->iseq[i+2] = arg >> 8;
-            irep->iseq[i+3] = arg & 0xff;
+            iseq[i] = OP_GETUPVAR;
+            iseq[i+2] = arg >> 8;
+            iseq[i+3] = arg & 0xff;
           }
         }
       }
       break;
 
     case OP_SETUPVAR:
-      a = PEEK_B(irep->iseq+i+1);
-      b = PEEK_B(irep->iseq+i+2);
-      c = PEEK_B(irep->iseq+i+3);
+      a = PEEK_B(iseq+i+1);
+      b = PEEK_B(iseq+i+2);
+      c = PEEK_B(iseq+i+3);
       {
         int lev = c+1;
         mrb_irep *tmp = search_irep(top, bnest, lev, irep);
@@ -191,25 +194,25 @@ patch_irep(mrb_state *mrb, mrb_irep *irep, int bnest, mrb_irep *top)
           uint16_t arg = search_variable(mrb, tmp->lv[b-1].name, bnest);
           if (arg != 0) {
             /* must replace */
-            irep->iseq[i] = OP_SETUPVAR;
-            irep->iseq[i+1] = a;
-            irep->iseq[i+2] = arg >> 8;
-            irep->iseq[i+3] = arg & 0xff;
+            iseq[i] = OP_SETUPVAR;
+            iseq[i+1] = a;
+            iseq[i+2] = arg >> 8;
+            iseq[i+3] = arg & 0xff;
           }
         }
       }
       break;
 
     case OP_EXT1:
-      insn = PEEK_B(irep->iseq+i+1);
+      insn = PEEK_B(iseq+i+1);
       i += mrb_insn_size1[insn]+1;
       continue;
     case OP_EXT2:
-      insn = PEEK_B(irep->iseq+i+1);
+      insn = PEEK_B(iseq+i+1);
       i += mrb_insn_size2[insn]+1;
       continue;
     case OP_EXT3:
-      insn = PEEK_B(irep->iseq+i+1);
+      insn = PEEK_B(iseq+i+1);
       i += mrb_insn_size3[insn]+1;
       continue;
     }
diff --git a/src/array.c b/src/array.c
index 70e2fcab7..33baceb9c 100644
--- a/src/array.c
+++ b/src/array.c
@@ -1259,7 +1259,7 @@ mrb_ary_svalue(mrb_state *mrb, mrb_value ary)
   }
 }
 
-static mrb_code each_iseq[] = {
+static const mrb_code each_iseq[] = {
   OP_ENTER, 0x0, 0x00, 0x1,  /* OP_ENTER     0:0:0:0:0:0:1 */
   OP_JMPIF, 0x1, 0x0, 19,    /* OP_JMPIF     R1  19 */
   OP_LOADSELF, 0x3,          /* OP_LOADSELF  R3 */
diff --git a/src/backtrace.c b/src/backtrace.c
index c9a223e07..8001849bc 100644
--- a/src/backtrace.c
+++ b/src/backtrace.c
@@ -26,7 +26,7 @@ typedef void (*each_backtrace_func)(mrb_state*, const struct backtrace_location*
 static const mrb_data_type bt_type = { "Backtrace", mrb_free };
 
 static void
-each_backtrace(mrb_state *mrb, ptrdiff_t ciidx, mrb_code *pc0, each_backtrace_func func, void *data)
+each_backtrace(mrb_state *mrb, ptrdiff_t ciidx, const mrb_code *pc0, each_backtrace_func func, void *data)
 {
   ptrdiff_t i;
 
@@ -37,7 +37,7 @@ each_backtrace(mrb_state *mrb, ptrdiff_t ciidx, mrb_code *pc0, each_backtrace_fu
     struct backtrace_location loc;
     mrb_callinfo *ci;
     mrb_irep *irep;
-    mrb_code *pc;
+    const mrb_code *pc;
 
     ci = &mrb->c->cibase[i];
 
diff --git a/src/class.c b/src/class.c
index 7e37973f6..43540dc3b 100644
--- a/src/class.c
+++ b/src/class.c
@@ -2123,7 +2123,7 @@ inspect_main(mrb_state *mrb, mrb_value mod)
   return mrb_str_new_lit(mrb, "main");
 }
 
-static mrb_code new_iseq[] = {
+static const mrb_code new_iseq[] = {
   OP_ENTER, 0x0, 0x10, 0x1,  /* OP_ENTER     0:0:1:0:0:0:1 */
   OP_LOADSELF, 0x3,          /* OP_LOADSELF  R3 */
   OP_SEND, 0x3, 0x0, 0x0,    /* OP_SEND      R3  :allocate  0 */
diff --git a/src/codedump.c b/src/codedump.c
index 12d609075..b77a8adb4 100644
--- a/src/codedump.c
+++ b/src/codedump.c
@@ -69,7 +69,7 @@ static void
 codedump(mrb_state *mrb, mrb_irep *irep)
 {
   int ai;
-  mrb_code *pc, *pcend;
+  const mrb_code *pc, *pcend;
   mrb_code ins;
   const char *file = NULL, *next_file;
 
diff --git a/src/error.c b/src/error.c
index 664da3fd6..bb8a0ba98 100644
--- a/src/error.c
+++ b/src/error.c
@@ -198,11 +198,11 @@ static void
 exc_debug_info(mrb_state *mrb, struct RObject *exc)
 {
   mrb_callinfo *ci = mrb->c->ci;
-  mrb_code *pc = ci->pc;
+  const mrb_code *pc = ci->pc;
 
   if (mrb_obj_iv_defined(mrb, exc, mrb_intern_lit(mrb, "file"))) return;
   while (ci >= mrb->c->cibase) {
-    mrb_code *err = ci->err;
+    const mrb_code *err = ci->err;
 
     if (!err && pc) err = pc - 1;
     if (err && ci->proc && !MRB_PROC_CFUNC_P(ci->proc)) {
diff --git a/src/load.c b/src/load.c
index 97eafdbb5..2aa2c576f 100644
--- a/src/load.c
+++ b/src/load.c
@@ -102,8 +102,9 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, size_t *len, uint8_t flag
     }
     else {
       size_t data_len = sizeof(mrb_code) * irep->ilen;
-      irep->iseq = (mrb_code *)mrb_malloc(mrb, data_len);
-      memcpy(irep->iseq, src, data_len);
+      void *buf = mrb_malloc(mrb, data_len);
+      irep->iseq = (mrb_code *)buf;
+      memcpy(buf, src, data_len);
       src += data_len;
     }
   }
diff --git a/src/proc.c b/src/proc.c
index a0edf22bc..ca398384f 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -9,7 +9,7 @@
 #include <mruby/proc.h>
 #include <mruby/opcode.h>
 
-static mrb_code call_iseq[] = {
+static const mrb_code call_iseq[] = {
   OP_CALL,
 };
 
@@ -256,7 +256,7 @@ mrb_int
 mrb_proc_arity(const struct RProc *p)
 {
   struct mrb_irep *irep;
-  mrb_code *pc;
+  const mrb_code *pc;
   mrb_aspec aspec;
   int ma, op, ra, pa, arity;
 
diff --git a/src/state.c b/src/state.c
index 69b069304..010a8d68a 100644
--- a/src/state.c
+++ b/src/state.c
@@ -117,7 +117,7 @@ mrb_irep_free(mrb_state *mrb, mrb_irep *irep)
   int i;
 
   if (!(irep->flags & MRB_ISEQ_NO_FREE))
-    mrb_free(mrb, irep->iseq);
+    mrb_free(mrb, (void*)irep->iseq);
   if (irep->pool) for (i=0; i<irep->plen; i++) {
     if (mrb_type(irep->pool[i]) == MRB_TT_STRING) {
       mrb_gc_free_str(mrb, RSTRING(irep->pool[i]));
diff --git a/src/vm.c b/src/vm.c
index 458b9249e..7ba49a32d 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -971,10 +971,10 @@ check_target_class(mrb_state *mrb)
 void mrb_hash_check_kdict(mrb_state *mrb, mrb_value self);
 
 MRB_API mrb_value
-mrb_vm_exec(mrb_state *mrb, struct RProc *proc, mrb_code *pc)
+mrb_vm_exec(mrb_state *mrb, struct RProc *proc, const mrb_code *pc)
 {
   /* mrb_assert(MRB_PROC_CFUNC_P(proc)) */
-  mrb_code *pc0 = pc;
+  const mrb_code *pc0 = pc;
   mrb_irep *irep = proc->body.irep;
   mrb_value *pool = irep->pool;
   mrb_sym *syms = irep->syms;