Merge pull request #1831 from monaka/pr-make-type-casts-safer

Make type casts safer

8 files changed, 245 insertions, 151 deletions

diff --git a/include/mruby/dump.h b/include/mruby/dump.h
index 69fd776b3..35546f9de 100644
--- a/include/mruby/dump.h
+++ b/include/mruby/dump.h
@@ -92,14 +92,14 @@ struct rite_binary_footer {
   RITE_SECTION_HEADER;
 };
 
-static inline int
+static inline size_t
 uint8_to_bin(uint8_t s, uint8_t *bin)
 {
   *bin = s;
   return sizeof(uint8_t);
 }
 
-static inline int
+static inline size_t
 uint16_to_bin(uint16_t s, uint8_t *bin)
 {
   *bin++ = (s >> 8) & 0xff;
@@ -107,7 +107,7 @@ uint16_to_bin(uint16_t s, uint8_t *bin)
   return sizeof(uint16_t);
 }
 
-static inline int
+static inline size_t
 uint32_to_bin(uint32_t l, uint8_t *bin)
 {
   *bin++ = (l >> 24) & 0xff;
diff --git a/include/mruby/string.h b/include/mruby/string.h
index 9ccbae56c..8a26192e6 100644
--- a/include/mruby/string.h
+++ b/include/mruby/string.h
@@ -15,7 +15,7 @@ extern "C" {
 
 extern const char mrb_digitmap[];
 
-#define RSTRING_EMBED_LEN_MAX (sizeof(void*) * 3 - 1)
+#define RSTRING_EMBED_LEN_MAX ((mrb_int)(sizeof(void*) * 3 - 1))
 
 struct RString {
   MRB_OBJECT_HEADER;
diff --git a/mrbgems/mruby-proc-ext/src/proc.c b/mrbgems/mruby-proc-ext/src/proc.c
index 0bf1204f5..4e41891a4 100644
--- a/mrbgems/mruby-proc-ext/src/proc.c
+++ b/mrbgems/mruby-proc-ext/src/proc.c
@@ -21,7 +21,7 @@ mrb_proc_source_location(mrb_state *mrb, mrb_value self)
   }
   else {
     mrb_irep *irep = p->body.irep;
-    uint32_t line;
+    int32_t line;
     const char *filename;
 
     filename = mrb_debug_get_filename(irep, 0);
diff --git a/src/class.c b/src/class.c
index 5a084b016..d880e3627 100644
--- a/src/class.c
+++ b/src/class.c
@@ -540,9 +540,12 @@ mrb_get_args(mrb_state *mrb, const char *format, ...)
 
         ps = va_arg(ap, char**);
         if (i < argc) {
+          size_t size_t_len;
           ss = to_str(mrb, *sp++);
           s = mrb_str_ptr(ss);
-          len = (mrb_int)strlen(RSTRING_PTR(ss));
+          size_t_len = strlen(RSTRING_PTR(ss));
+          mrb_assert(size_t_len <= MRB_INT_MAX);
+          len = (mrb_int)size_t_len;
           if (len < RSTRING_LEN(ss)) {
             mrb_raise(mrb, E_ARGUMENT_ERROR, "string contains null byte");
           }
diff --git a/src/codegen.c b/src/codegen.c
index 0b4d18bba..700cfdbf8 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -5,6 +5,7 @@
 */
 
 #include <ctype.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include "mruby.h"
@@ -2582,14 +2583,16 @@ static void
 codedump(mrb_state *mrb, mrb_irep *irep)
 {
 #ifdef ENABLE_STDIO
-  uint32_t i;
+  int i;
   int ai;
   mrb_code c;
 
   if (!irep) return;
   printf("irep %p nregs=%d nlocals=%d pools=%d syms=%d reps=%d\n", irep,
          irep->nregs, irep->nlocals, (int)irep->plen, (int)irep->slen, (int)irep->rlen);
-  for (i=0; i<irep->ilen; i++) {
+
+  mrb_assert(irep->ilen <= INT_MAX);
+  for (i = 0; i < (int)(irep->ilen); i++) {
     ai = mrb_gc_arena_save(mrb);
     printf("%03d ", i);
     c = irep->iseq[i];
diff --git a/src/dump.c b/src/dump.c
index 72d1ffcbe..b9e02fe77 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -12,12 +12,16 @@
 #include "mruby/numeric.h"
 #include "mruby/debug.h"
 
-static uint32_t get_irep_record_size_1(mrb_state *mrb, mrb_irep *irep);
+static size_t get_irep_record_size_1(mrb_state *mrb, mrb_irep *irep);
 
-static uint32_t
+#if UINT32_MAX > SIZE_MAX
+# error This code cannot be built on your environment.
+#endif
+
+static size_t
 get_irep_header_size(mrb_state *mrb)
 {
-  uint32_t size = 0;
+  size_t size = 0;
 
   size += sizeof(uint32_t) * 1;
   size += sizeof(uint16_t) * 3;
@@ -25,7 +29,7 @@ get_irep_header_size(mrb_state *mrb)
   return size;
 }
 
-static uint32_t
+static ptrdiff_t
 write_irep_header(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
 {
   uint8_t *cur = buf;
@@ -35,20 +39,22 @@ write_irep_header(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
   cur += uint16_to_bin((uint16_t)irep->nregs, cur);  /* number of register variable */
   cur += uint16_to_bin((uint16_t)irep->rlen, cur);  /* number of child irep */
 
-  return (cur - buf);
+  return cur - buf;
 }
 
 
-static uint32_t
+static size_t
 get_iseq_block_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
+  size_t size = 0;
+
   size += sizeof(uint32_t); /* ilen */
   size += sizeof(uint32_t) * irep->ilen; /* iseq(n) */
+
   return size;
 }
 
-static uint32_t
+static ptrdiff_t
 write_iseq_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
 {
   uint8_t *cur = buf;
@@ -59,16 +65,15 @@ write_iseq_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
     cur += uint32_to_bin(irep->iseq[iseq_no], cur); /* opcode */
   }
 
-  return (cur - buf);
+  return cur - buf;
 }
 
 
-static uint32_t
+static size_t
 get_pool_block_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
-  uint32_t pool_no;
-  int len;
+  size_t size = 0;
+  size_t pool_no;
   mrb_value str;
   char buf[32];
 
@@ -81,16 +86,31 @@ get_pool_block_size(mrb_state *mrb, mrb_irep *irep)
     switch (mrb_type(irep->pool[pool_no])) {
     case MRB_TT_FIXNUM:
       str = mrb_fixnum_to_str(mrb, irep->pool[pool_no], 10);
-      size += RSTRING_LEN(str);
+      {
+        mrb_int len = RSTRING_LEN(str);
+        mrb_assert(len >= 0);
+        mrb_assert((size_t)len <= SIZE_MAX);
+        size += (size_t)len;
+      }
       break;
 
     case MRB_TT_FLOAT:
-      len = mrb_float_to_str(buf, mrb_float(irep->pool[pool_no]));
-      size += len;
+      {
+        int len;
+        len = mrb_float_to_str(buf, mrb_float(irep->pool[pool_no]));
+        mrb_assert(len >= 0);
+        mrb_assert((size_t)len <= SIZE_MAX);
+        size += (size_t)len;
+      }
       break;
 
     case MRB_TT_STRING:
-      size += RSTRING_LEN(irep->pool[pool_no]);
+      {
+        mrb_int len = RSTRING_LEN(irep->pool[pool_no]);
+        mrb_assert(len >= 0);
+        mrb_assert((size_t)len <= SIZE_MAX);
+        size += (size_t)len;
+      }
       break;
 
     default:
@@ -102,12 +122,12 @@ get_pool_block_size(mrb_state *mrb, mrb_irep *irep)
   return size;
 }
 
-static uint32_t
+static ptrdiff_t
 write_pool_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
 {
-  uint32_t pool_no;
+  size_t pool_no;
   uint8_t *cur = buf;
-  uint32_t len;
+  uint16_t len;
   mrb_value str;
   const char *char_ptr;
   char char_buf[30];
@@ -122,19 +142,37 @@ write_pool_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
       cur += uint8_to_bin(IREP_TT_FIXNUM, cur); /* data type */
       str = mrb_fixnum_to_str(mrb, irep->pool[pool_no], 10);
       char_ptr = RSTRING_PTR(str);
-      len = RSTRING_LEN(str);
+      {
+        mrb_int tlen;
+        tlen = RSTRING_LEN(str);
+        mrb_assert(tlen >= 0);
+        mrb_assert(tlen <= INT16_MAX);
+        len = (uint16_t)tlen;
+      }
       break;
 
     case MRB_TT_FLOAT:
       cur += uint8_to_bin(IREP_TT_FLOAT, cur); /* data type */
-      len = mrb_float_to_str(char_buf, mrb_float(irep->pool[pool_no]));
+      {
+        int tlen;
+        tlen = mrb_float_to_str(char_buf, mrb_float(irep->pool[pool_no]));
+        mrb_assert(tlen >= 0);
+        mrb_assert(tlen <= INT16_MAX);
+        len = (uint16_t)tlen;
+      }
       char_ptr = &char_buf[0];
       break;
 
     case MRB_TT_STRING:
       cur += uint8_to_bin(IREP_TT_STRING, cur); /* data type */
       char_ptr = RSTRING_PTR(irep->pool[pool_no]);
-      len = RSTRING_LEN(irep->pool[pool_no]);
+      {
+        mrb_int tlen;
+        tlen = RSTRING_LEN(irep->pool[pool_no]);
+        mrb_assert(tlen >= 0);
+        mrb_assert(tlen <= INT16_MAX);
+        len = (uint16_t)tlen;
+      }
       break;
 
     default:
@@ -142,20 +180,20 @@ write_pool_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
     }
 
     cur += uint16_to_bin(len, cur); /* data length */
-    memcpy(cur, char_ptr, len);
+    memcpy(cur, char_ptr, (size_t)len);
     cur += len;
 
     mrb_gc_arena_restore(mrb, ai);
   }
 
-  return (uint32_t)(cur - buf);
+  return cur - buf;
 }
 
 
-static uint32_t
+static size_t
 get_syms_block_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
+  size_t size = 0;
   uint32_t sym_no;
   size_t len;
 
@@ -171,7 +209,7 @@ get_syms_block_size(mrb_state *mrb, mrb_irep *irep)
   return size;
 }
 
-static uint32_t
+static ptrdiff_t
 write_syms_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
 {
   uint32_t sym_no;
@@ -185,10 +223,8 @@ write_syms_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
       size_t len;
 
       name = mrb_sym2name_len(mrb, irep->syms[sym_no], &len);
-      if (len > UINT16_MAX) {
-        return MRB_DUMP_GENERAL_FAILURE;
-      }
 
+      mrb_assert(len <= UINT16_MAX);
       cur += uint16_to_bin((uint16_t)len, cur); /* length of symbol name */
       memcpy(cur, name, len); /* symbol name */
       cur += (uint16_t)len;
@@ -199,13 +235,13 @@ write_syms_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf)
     }
   }
 
-  return (uint32_t)(cur - buf);
+  return cur - buf;
 }
 
-static uint32_t
+static size_t
 get_irep_record_size_1(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
+  size_t size = 0;
 
   size += get_irep_header_size(mrb);
   size += get_iseq_block_size(mrb, irep);
@@ -214,11 +250,11 @@ get_irep_record_size_1(mrb_state *mrb, mrb_irep *irep)
   return size;
 }
 
-static uint32_t
+static size_t
 get_irep_record_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
-  uint32_t irep_no;
+  size_t size = 0;
+  size_t irep_no;
   
   size = get_irep_record_size_1(mrb, irep);
   for (irep_no = 0; irep_no < irep->rlen; irep_no++) {
@@ -228,7 +264,7 @@ get_irep_record_size(mrb_state *mrb, mrb_irep *irep)
 }
 
 static int
-write_irep_record(mrb_state *mrb, mrb_irep *irep, uint8_t* bin, uint32_t *irep_record_size)
+write_irep_record(mrb_state *mrb, mrb_irep *irep, uint8_t* bin, size_t *irep_record_size)
 {
   uint32_t i;
 
@@ -250,14 +286,14 @@ write_irep_record(mrb_state *mrb, mrb_irep *irep, uint8_t* bin, uint32_t *irep_r
 
   for (i = 0; i < irep->rlen; i++) {
     int result;
-    uint32_t rlen;
+    size_t rsize;
 
-    result = write_irep_record(mrb, irep->reps[i], bin, &rlen);
+    result = write_irep_record(mrb, irep->reps[i], bin, &rsize);
     if (result != MRB_DUMP_OK) {
       return result;
     }
-    *irep_record_size += rlen;
-    bin += rlen;
+    *irep_record_size += rsize;
+    bin += rsize;
   }
   return MRB_DUMP_OK;
 }
@@ -276,12 +312,13 @@ write_footer(mrb_state *mrb, uint8_t *bin)
 
 
 static int
-write_section_irep_header(mrb_state *mrb, uint32_t section_size, uint8_t *bin)
+write_section_irep_header(mrb_state *mrb, size_t section_size, uint8_t *bin)
 {
   struct rite_section_irep_header *header = (struct rite_section_irep_header*)bin;
 
   memcpy(header->section_identify, RITE_SECTION_IREP_IDENTIFIER, sizeof(header->section_identify));
-  uint32_to_bin(section_size, header->section_size);
+  mrb_assert(section_size <= UINT32_MAX);
+  uint32_to_bin((uint32_t)section_size, header->section_size);
   memcpy(header->rite_version, RITE_VM_VER, sizeof(header->rite_version));
 
   return MRB_DUMP_OK;
@@ -291,7 +328,8 @@ static int
 write_section_irep(mrb_state *mrb, mrb_irep *irep, uint8_t *bin)
 {
   int result;
-  uint32_t section_size = 0, rlen = 0; /* size of irep record */
+  size_t section_size = 0; /* size of irep record */
+  size_t rsize = 0;
   uint8_t *cur = bin;
 
   if (mrb == NULL || bin == NULL) {
@@ -301,33 +339,32 @@ write_section_irep(mrb_state *mrb, mrb_irep *irep, uint8_t *bin)
   cur += sizeof(struct rite_section_irep_header);
   section_size += sizeof(struct rite_section_irep_header);
 
-  result = write_irep_record(mrb, irep, cur, &rlen);
+  result = write_irep_record(mrb, irep, cur, &rsize);
   if (result != MRB_DUMP_OK) {
     return result;
   }
-  cur += rlen;
-  section_size += rlen;
+  cur += rsize;
+  section_size += rsize;
   write_section_irep_header(mrb, section_size, bin);
 
   return MRB_DUMP_OK;
 }
 
 static int
-write_section_lineno_header(mrb_state *mrb, uint32_t section_size, uint8_t *bin)
+write_section_lineno_header(mrb_state *mrb, size_t section_size, uint8_t *bin)
 {
   struct rite_section_lineno_header *header = (struct rite_section_lineno_header*)bin;
 
-  /* TODO */
   memcpy(header->section_identify, RITE_SECTION_LINENO_IDENTIFIER, sizeof(header->section_identify));
-  uint32_to_bin(section_size, header->section_size);
+  uint32_to_bin((uint32_t)section_size, header->section_size);
 
   return MRB_DUMP_OK;
 }
 
-static uint32_t
+static size_t
 get_lineno_record_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t size = 0;
+  size_t size = 0;
 
   size += sizeof(uint32_t); /* record size */
   size += sizeof(uint16_t); /* filename size */
@@ -338,21 +375,27 @@ get_lineno_record_size(mrb_state *mrb, mrb_irep *irep)
   if (irep->lines) {
     size += sizeof(uint16_t) * irep->ilen; /* lineno */
   }
+
   return size;
 }
 
-static int
+static size_t
 write_lineno_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t* bin)
 {
   uint8_t *cur = bin;
-  uint32_t filename_len = 0, iseq_no;
+  size_t iseq_no;
+  size_t filename_len;
+  ptrdiff_t diff;
 
   cur += sizeof(uint32_t); /* record size */
 
   if (irep->filename) {
     filename_len = strlen(irep->filename);
+  } else {
+    filename_len = 0;
   }
-  cur += uint16_to_bin(filename_len, cur); /* filename size */
+  mrb_assert(filename_len <= UINT16_MAX);
+  cur += uint16_to_bin((uint16_t)filename_len, cur); /* filename size */
 
   if (filename_len) {
     memcpy(cur, irep->filename, filename_len);
@@ -360,7 +403,8 @@ write_lineno_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t* bin)
   }
 
   if (irep->lines) {
-    cur += uint32_to_bin(irep->ilen, cur); /* niseq */
+    mrb_assert(irep->ilen <= UINT32_MAX);
+    cur += uint32_to_bin((uint32_t)(irep->ilen), cur); /* niseq */
     for (iseq_no = 0; iseq_no < irep->ilen; iseq_no++) {
       cur += uint16_to_bin(irep->lines[iseq_no], cur); /* opcode */
     }
@@ -369,16 +413,21 @@ write_lineno_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t* bin)
     cur += uint32_to_bin(0, cur); /* niseq */
   }
 
-  uint32_to_bin(cur - bin, bin); /* record size */
+  diff = cur - bin;
+  mrb_assert(diff >= 0);
+  mrb_assert(diff <= UINT32_MAX);
+
+  uint32_to_bin((uint32_t)diff, bin); /* record size */
 
-  return (cur - bin);
+  mrb_assert((size_t)diff <= SIZE_MAX);
+  return (size_t)diff;
 }
 
-static int
+static size_t
 write_lineno_record(mrb_state *mrb, mrb_irep *irep, uint8_t* bin)
 {
-  uint32_t i;
-  uint32_t rlen, size = 0;
+  size_t i;
+  size_t rlen, size = 0;
 
   rlen = write_lineno_record_1(mrb, irep, bin);
   bin += rlen;
@@ -394,7 +443,8 @@ write_lineno_record(mrb_state *mrb, mrb_irep *irep, uint8_t* bin)
 static int
 write_section_lineno(mrb_state *mrb, mrb_irep *irep, uint8_t *bin)
 {
-  uint32_t section_size = 0, rlen = 0; /* size of irep record */
+  size_t section_size = 0;
+  size_t rlen = 0; /* size of irep record */
   uint8_t *cur = bin;
 
   if (mrb == NULL || bin == NULL) {
@@ -412,11 +462,12 @@ write_section_lineno(mrb_state *mrb, mrb_irep *irep, uint8_t *bin)
   return MRB_DUMP_OK;
 }
 
-static uint32_t
+static size_t
 get_debug_record_size(mrb_state *mrb, mrb_irep *irep)
 {
-  uint32_t ret = 0, f_idx;
-  uint32_t i;
+  size_t ret = 0;
+  uint16_t f_idx;
+  size_t i;
 
   ret += sizeof(uint32_t); /* record size */
   ret += sizeof(uint16_t); /* file count */
@@ -432,11 +483,11 @@ get_debug_record_size(mrb_state *mrb, mrb_irep *irep)
     ret += sizeof(uint8_t); /* line type */
     switch(file->line_type) {
       case mrb_debug_line_ary:
-        ret += sizeof(uint16_t) * file->line_entry_count;
+        ret += sizeof(uint16_t) * (size_t)(file->line_entry_count);
         break;
 
       case mrb_debug_line_flat_map:
-        ret += (sizeof(uint32_t) + sizeof(uint16_t)) * file->line_entry_count;
+        ret += (sizeof(uint32_t) + sizeof(uint16_t)) * (size_t)(file->line_entry_count);
         break;
 
       default: mrb_assert(0); break;
@@ -450,9 +501,9 @@ get_debug_record_size(mrb_state *mrb, mrb_irep *irep)
 }
 
 static int
-find_filename_index(const mrb_sym *ary, uint32_t ary_len, mrb_sym s)
+find_filename_index(const mrb_sym *ary, uint16_t ary_len, mrb_sym s)
 {
-  uint32_t i;
+  int i;
 
   for (i = 0; i < ary_len; ++i) {
     if (ary[i] == s) { return i; }
@@ -460,13 +511,13 @@ find_filename_index(const mrb_sym *ary, uint32_t ary_len, mrb_sym s)
   return -1;
 }
 
-static uint32_t
-get_filename_table_size(mrb_state *mrb, mrb_irep *irep, mrb_sym **fp, uint32_t *lp)
+static size_t
+get_filename_table_size(mrb_state *mrb, mrb_irep *irep, mrb_sym **fp, uint16_t *lp)
 {
   mrb_sym *filenames = *fp;
-  uint32_t tsize = 0;
+  uint16_t tsize = 0;
   uint32_t file_i;
-  uint32_t size = 0;
+  size_t size = 0;
   mrb_irep_debug_info *di = irep->debug_info;
 
   if (lp == NULL) {
@@ -496,12 +547,12 @@ get_filename_table_size(mrb_state *mrb, mrb_irep *irep, mrb_sym **fp, uint32_t *
   return size;
 }
 
-static int
-write_debug_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const* filenames, uint32_t filenames_len)
+static size_t
+write_debug_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const* filenames, uint16_t filenames_len)
 {
   uint8_t *cur;
-  uint32_t f_idx;
-  uint32_t ret;
+  uint16_t f_idx;
+  ptrdiff_t ret;
 
   cur = bin + sizeof(uint32_t); /* skip record size */
   cur += uint16_to_bin(irep->debug_info->flen, cur); /* file count */
@@ -516,8 +567,9 @@ write_debug_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const
     /* filename index */
     filename_idx = find_filename_index(filenames, filenames_len,
                                                   file->filename_sym);
-    mrb_assert(filename_idx != -1);
-    cur += uint16_to_bin(filename_idx, cur);
+    mrb_assert(filename_idx >= 0);
+    mrb_assert(filename_idx <= UINT16_MAX);
+    cur += uint16_to_bin((uint16_t)filename_idx, cur);
 
     /* lines */
     cur += uint32_to_bin(file->line_entry_count, cur);
@@ -543,16 +595,19 @@ write_debug_record_1(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const
   }
 
   ret = cur - bin;
+  mrb_assert(ret >= 0);
+  mrb_assert(ret <= UINT32_MAX);
   uint32_to_bin(ret, bin);
 
-  return ret;
+  mrb_assert((size_t)ret <= SIZE_MAX);
+  return (size_t)ret;
 }
 
-static uint32_t
-write_debug_record(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const* filenames, uint32_t filenames_len)
+static size_t
+write_debug_record(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const* filenames, uint16_t filenames_len)
 {
-  uint32_t size, len;
-  uint32_t irep_no;
+  size_t size, len;
+  size_t irep_no;
   
   size = len = write_debug_record_1(mrb, irep, bin, filenames, filenames_len);
   bin += len;
@@ -566,14 +621,14 @@ write_debug_record(mrb_state *mrb, mrb_irep *irep, uint8_t *bin, mrb_sym const*
   return size;
 }
 
-static uint32_t
-write_filename_table(mrb_state *mrb, mrb_irep *irep, uint8_t **cp, mrb_sym **fp, uint32_t *lp)
+static size_t
+write_filename_table(mrb_state *mrb, mrb_irep *irep, uint8_t **cp, mrb_sym **fp, uint16_t *lp)
 {
   uint8_t *cur = *cp;
   mrb_sym *filenames = *fp;
   uint32_t file_i;
   uint16_t fn_len;
-  uint32_t size = 0;
+  size_t size = 0;
   mrb_irep_debug_info *debug_info = irep->debug_info;
 
   for (file_i = 0; file_i < debug_info->flen; ++file_i) {
@@ -603,13 +658,13 @@ write_filename_table(mrb_state *mrb, mrb_irep *irep, uint8_t **cp, mrb_sym **fp,
 static int
 write_section_debug(mrb_state *mrb, mrb_irep *irep, uint8_t *cur)
 {
-  uint32_t section_size = 0;
+  size_t section_size = 0;
   const uint8_t *bin = cur;
   struct rite_section_debug_header *header;
   mrb_sym *filenames;
-  uint32_t filenames_len = 0;
+  uint16_t filenames_len = 0;
   uint8_t *filenames_len_out;
-  uint32_t dlen;
+  size_t dlen;
 
   if (mrb == NULL || cur == NULL) {
     return MRB_DUMP_INVALID_ARGUMENT;
@@ -632,6 +687,7 @@ write_section_debug(mrb_state *mrb, mrb_irep *irep, uint8_t *cur)
   section_size += dlen;
 
   memcpy(header->section_identify, RITE_SECTION_DEBUG_IDENTIFIER, sizeof(header->section_identify));
+  mrb_assert(section_size <= INT32_MAX);
   uint32_to_bin(section_size, header->section_size);
 
   mrb_free(mrb, filenames);
@@ -640,7 +696,7 @@ write_section_debug(mrb_state *mrb, mrb_irep *irep, uint8_t *cur)
 }
 
 static int
-write_rite_binary_header(mrb_state *mrb, uint32_t binary_size, uint8_t *bin)
+write_rite_binary_header(mrb_state *mrb, size_t binary_size, uint8_t *bin)
 {
   struct rite_binary_header *header = (struct rite_binary_header *)bin;
   uint16_t crc;
@@ -650,7 +706,8 @@ write_rite_binary_header(mrb_state *mrb, uint32_t binary_size, uint8_t *bin)
   memcpy(header->binary_version, RITE_BINARY_FORMAT_VER, sizeof(header->binary_version));
   memcpy(header->compiler_name, RITE_COMPILER_NAME, sizeof(header->compiler_name));
   memcpy(header->compiler_version, RITE_COMPILER_VERSION, sizeof(header->compiler_version));
-  uint32_to_bin(binary_size, header->binary_size);
+  mrb_assert(binary_size <= UINT32_MAX);
+  uint32_to_bin((uint32_t)binary_size, header->binary_size);
 
   offset = (&(header->binary_crc[0]) - bin) + sizeof(uint16_t);
   crc = calc_crc_16_ccitt(bin + offset, binary_size - offset, 0);
@@ -662,7 +719,7 @@ write_rite_binary_header(mrb_state *mrb, uint32_t binary_size, uint8_t *bin)
 static mrb_bool
 is_debug_info_defined(mrb_irep *irep)
 {
-  uint32_t i;
+  size_t i;
 
   if (!irep->debug_info) return 0;
   for (i=0; i<irep->rlen; i++) {
@@ -672,11 +729,11 @@ is_debug_info_defined(mrb_irep *irep)
 }
 
 static int
-dump_irep(mrb_state *mrb, mrb_irep *irep, int debug_info, uint8_t **bin, uint32_t *bin_size)
+dump_irep(mrb_state *mrb, mrb_irep *irep, int debug_info, uint8_t **bin, size_t *bin_size)
 {
   int result = MRB_DUMP_GENERAL_FAILURE;
-  uint32_t section_irep_size;
-  uint32_t section_lineno_size = 0;
+  size_t section_irep_size;
+  size_t section_lineno_size = 0;
   uint8_t *cur = NULL;
   mrb_bool const debug_info_defined = is_debug_info_defined(irep);
 
@@ -757,7 +814,7 @@ int
 mrb_dump_irep_binary(mrb_state *mrb, mrb_irep *irep, int debug_info, FILE* fp)
 {
   uint8_t *bin = NULL;
-  uint32_t bin_size = 0;
+  size_t bin_size = 0;
   int result;
 
   if (fp == NULL) {
@@ -793,7 +850,7 @@ int
 mrb_dump_irep_cfunc(mrb_state *mrb, mrb_irep *irep, int debug_info, FILE *fp, const char *initname)
 {
   uint8_t *bin = NULL;
-  uint32_t bin_size = 0, bin_idx = 0;
+  size_t bin_size = 0, bin_idx = 0;
   int result;
 
   if (fp == NULL || initname == NULL || !is_valid_c_symbol_name(initname)) {
diff --git a/src/load.c b/src/load.c
index de517f89f..aa39efba4 100644
--- a/src/load.c
+++ b/src/load.c
@@ -26,6 +26,10 @@
 # error This code assumes CHAR_BIT == 8
 #endif
 
+#if UINT32_MAX > SIZE_MAX
+# error This code cannot be built on your environment.
+#endif
+
 static size_t
 offset_crc_body(void)
 {
@@ -34,10 +38,11 @@ offset_crc_body(void)
 }
 
 static mrb_irep*
-read_irep_record_1(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool alloc)
+read_irep_record_1(mrb_state *mrb, const uint8_t *bin, size_t *len, mrb_bool alloc)
 {
   size_t i;
   const uint8_t *src = bin;
+  ptrdiff_t diff;
   uint16_t tt, pool_data_len, snl;
   size_t plen;
   int ai = mrb_gc_arena_save(mrb);
@@ -55,12 +60,12 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool a
   src += sizeof(uint16_t);
 
   /* number of child irep */
-  irep->rlen = bin_to_uint16(src);
+  irep->rlen = (size_t)bin_to_uint16(src);
   src += sizeof(uint16_t);
 
   /* Binary Data Section */
   /* ISEQ BLOCK */
-  irep->ilen = bin_to_uint32(src);
+  irep->ilen = (size_t)bin_to_uint32(src);
   src += sizeof(uint32_t);
   if (irep->ilen > 0) {
     if (SIZE_ERROR_MUL(sizeof(mrb_code), irep->ilen)) {
@@ -71,13 +76,13 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool a
       return NULL;
     }
     for (i = 0; i < irep->ilen; i++) {
-      irep->iseq[i] = bin_to_uint32(src);     /* iseq */
+      irep->iseq[i] = (size_t)bin_to_uint32(src);     /* iseq */
       src += sizeof(uint32_t);
     }
   }
 
   /* POOL BLOCK */
-  plen = bin_to_uint32(src); /* number of pool */
+  plen = (size_t)bin_to_uint32(src); /* number of pool */
   src += sizeof(uint32_t);
   if (plen > 0) {
     if (SIZE_ERROR_MUL(sizeof(mrb_value), plen)) {
@@ -125,7 +130,7 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool a
   }
 
   /* SYMS BLOCK */
-  irep->slen = bin_to_uint32(src);  /* syms length */
+  irep->slen = (size_t)bin_to_uint32(src);  /* syms length */
   src += sizeof(uint32_t);
   if (irep->slen > 0) {
     if (SIZE_ERROR_MUL(sizeof(mrb_sym), irep->slen)) {
@@ -158,20 +163,24 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool a
   }
 
   irep->reps = (mrb_irep**)mrb_malloc(mrb, sizeof(mrb_irep*)*irep->rlen);
-  *len = src - bin;
+
+  diff = src - bin;
+  mrb_assert(diff >= 0);
+  mrb_assert((size_t)diff <= SIZE_MAX);
+  *len = (size_t)diff;
 
   return irep;
 }
 
 static mrb_irep*
-read_irep_record(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool alloc)
+read_irep_record(mrb_state *mrb, const uint8_t *bin, size_t *len, mrb_bool alloc)
 {
   mrb_irep *irep = read_irep_record_1(mrb, bin, len, alloc);
   size_t i;
 
   bin += *len;
   for (i=0; i<irep->rlen; i++) {
-    uint32_t rlen;
+    size_t rlen;
 
     irep->reps[i] = read_irep_record(mrb, bin, &rlen, alloc);
     bin += rlen;
@@ -183,14 +192,14 @@ read_irep_record(mrb_state *mrb, const uint8_t *bin, uint32_t *len, mrb_bool all
 static mrb_irep*
 read_section_irep(mrb_state *mrb, const uint8_t *bin, mrb_bool alloc)
 {
-  uint32_t len;
+  size_t len;
 
   bin += sizeof(struct rite_section_irep_header);
   return read_irep_record(mrb, bin, &len, alloc);
 }
 
 static int
-read_lineno_record_1(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, uint32_t *len)
+read_lineno_record_1(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, size_t *len)
 {
   int ret;
   size_t i, fname_len, niseq;
@@ -216,7 +225,7 @@ read_lineno_record_1(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, uint32_
   bin += fname_len;
   *len += fname_len;
 
-  niseq = bin_to_uint32(bin);
+  niseq = (size_t)bin_to_uint32(bin);
   bin += sizeof(uint32_t); /* niseq */
   *len += sizeof(uint32_t);
 
@@ -239,14 +248,14 @@ read_lineno_record_1(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, uint32_
 }
 
 static int
-read_lineno_record(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, uint32_t *lenp)
+read_lineno_record(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, size_t *lenp)
 {
   int result = read_lineno_record_1(mrb, bin, irep, lenp);
   size_t i;
 
   if (result != MRB_DUMP_OK) return result;
   for (i = 0; i < irep->rlen; i++) {
-    uint32_t len;
+    size_t len;
 
     result = read_lineno_record(mrb, bin, irep->reps[i], &len);
     if (result != MRB_DUMP_OK) break;
@@ -259,7 +268,7 @@ read_lineno_record(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep, uint32_t
 static int
 read_section_lineno(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep)
 {
-  uint32_t len;
+  size_t len;
 
   len = 0;
   bin += sizeof(struct rite_section_lineno_header);
@@ -269,9 +278,10 @@ read_section_lineno(mrb_state *mrb, const uint8_t *bin, mrb_irep *irep)
 }
 
 static int
-read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t *len, const mrb_sym *filenames, size_t filenames_len)
+read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, size_t *record_len, const mrb_sym *filenames, size_t filenames_len)
 {
   const uint8_t *bin = start;
+  ptrdiff_t diff;
   size_t record_size, i;
   uint16_t f_idx;
 
@@ -280,7 +290,7 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t
   irep->debug_info = (mrb_irep_debug_info*)mrb_malloc(mrb, sizeof(mrb_irep_debug_info));
   irep->debug_info->pc_count = irep->ilen;
 
-  record_size = bin_to_uint32(bin);
+  record_size = (size_t)bin_to_uint32(bin);
   bin += sizeof(uint32_t);
 
   irep->debug_info->flen = bin_to_uint16(bin);
@@ -295,7 +305,8 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t
     file = (mrb_irep_debug_info_file *)mrb_malloc(mrb, sizeof(*file));
     irep->debug_info->files[f_idx] = file;
 
-    file->start_pos = bin_to_uint32(bin); bin += sizeof(uint32_t);
+    file->start_pos = bin_to_uint32(bin);
+    bin += sizeof(uint32_t);
 
     /* filename */
     filename_idx = bin_to_uint16(bin);
@@ -305,26 +316,31 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t
     len = 0;
     file->filename = mrb_sym2name_len(mrb, file->filename_sym, &len);
 
-    file->line_entry_count = bin_to_uint32(bin); bin += sizeof(uint32_t);
-    file->line_type = (mrb_debug_line_type)bin_to_uint8(bin); bin += sizeof(uint8_t);
+    file->line_entry_count = bin_to_uint32(bin);
+    bin += sizeof(uint32_t);
+    file->line_type = (mrb_debug_line_type)bin_to_uint8(bin);
+    bin += sizeof(uint8_t);
     switch(file->line_type) {
       case mrb_debug_line_ary: {
-        size_t l;
+        uint32_t l;
 
-        file->line_ary = (uint16_t *)mrb_malloc(mrb, sizeof(uint16_t) * file->line_entry_count);
+        file->line_ary = (uint16_t *)mrb_malloc(mrb, sizeof(uint16_t) * (size_t)(file->line_entry_count));
         for(l = 0; l < file->line_entry_count; ++l) {
-          file->line_ary[l] = bin_to_uint16(bin); bin += sizeof(uint16_t);
+          file->line_ary[l] = bin_to_uint16(bin);
+          bin += sizeof(uint16_t);
         }
       } break;
 
       case mrb_debug_line_flat_map: {
-        size_t l;
+        uint32_t l;
 
         file->line_flat_map = (mrb_irep_debug_info_line*)mrb_malloc(
-            mrb, sizeof(mrb_irep_debug_info_line) * file->line_entry_count);
+            mrb, sizeof(mrb_irep_debug_info_line) * (size_t)(file->line_entry_count));
         for(l = 0; l < file->line_entry_count; ++l) {
-          file->line_flat_map[l].start_pos = bin_to_uint32(bin); bin += sizeof(uint32_t);
-          file->line_flat_map[l].line = bin_to_uint16(bin); bin += sizeof(uint16_t);
+          file->line_flat_map[l].start_pos = bin_to_uint32(bin);
+          bin += sizeof(uint32_t);
+          file->line_flat_map[l].line = bin_to_uint16(bin);
+          bin += sizeof(uint16_t);
         }
       } break;
 
@@ -332,12 +348,16 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t
     }
   }
 
-  if((long)record_size != (bin - start)) {
+  diff = bin - start;
+  mrb_assert(diff >= 0);
+  mrb_assert((size_t)diff <= SIZE_MAX);
+
+  if(record_size != (size_t)diff) {
     return MRB_DUMP_GENERAL_FAILURE;
   }
 
   for (i = 0; i < irep->rlen; i++) {
-    uint32_t len;
+    size_t len;
     int ret;
 
     ret =read_debug_record(mrb, bin, irep->reps[i], &len, filenames, filenames_len);
@@ -345,7 +365,10 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, uint32_t
     bin += len;
   }
 
-  *len = bin - start;
+  diff = bin - start;
+  mrb_assert(diff >= 0);
+  mrb_assert((size_t)diff <= SIZE_MAX);
+  *record_len = (size_t)diff;
 
   return MRB_DUMP_OK;
 }
@@ -354,11 +377,12 @@ static int
 read_section_debug(mrb_state *mrb, const uint8_t *start, mrb_irep *irep, mrb_bool alloc)
 {
   const uint8_t *bin;
+  ptrdiff_t diff;
   struct rite_section_debug_header *header;
   uint16_t i;
-  uint32_t len = 0;
+  size_t len = 0;
   int result;
-  size_t filenames_len;
+  uint16_t filenames_len;
   mrb_sym *filenames;
 
   bin = start;
@@ -367,15 +391,15 @@ read_section_debug(mrb_state *mrb, const uint8_t *start, mrb_irep *irep, mrb_boo
 
   filenames_len = bin_to_uint16(bin);
   bin += sizeof(uint16_t);
-  filenames = (mrb_sym*)mrb_malloc(mrb, sizeof(mrb_sym) * filenames_len);
+  filenames = (mrb_sym*)mrb_malloc(mrb, sizeof(mrb_sym) * (size_t)filenames_len);
   for(i = 0; i < filenames_len; ++i) {
     uint16_t f_len = bin_to_uint16(bin);
     bin += sizeof(uint16_t);
     if (alloc) {
-      filenames[i] = mrb_intern(mrb, (const char *)bin, f_len);
+      filenames[i] = mrb_intern(mrb, (const char *)bin, (size_t)f_len);
     }
     else {
-      filenames[i] = mrb_intern_static(mrb, (const char *)bin, f_len);
+      filenames[i] = mrb_intern_static(mrb, (const char *)bin, (size_t)f_len);
     }
     bin += f_len;
   }
@@ -384,7 +408,10 @@ read_section_debug(mrb_state *mrb, const uint8_t *start, mrb_irep *irep, mrb_boo
   if (result != MRB_DUMP_OK) goto debug_exit;
 
   bin += len;
-  if ((bin - start) != bin_to_uint32(header->section_size)) {
+  diff = bin - start;
+  mrb_assert(diff >= 0);
+  mrb_assert(diff <= UINT32_MAX);
+  if ((uint32_t)diff != bin_to_uint32(header->section_size)) {
     result = MRB_DUMP_GENERAL_FAILURE;
   }
 
@@ -408,7 +435,7 @@ read_binary_header(const uint8_t *bin, size_t *bin_size, uint16_t *crc)
 
   *crc = bin_to_uint16(header->binary_crc);
   if (bin_size) {
-    *bin_size = bin_to_uint32(header->binary_size);
+    *bin_size = (size_t)bin_to_uint32(header->binary_size);
   }
 
   return MRB_DUMP_OK;
@@ -504,14 +531,14 @@ read_lineno_record_file(mrb_state *mrb, FILE *fp, mrb_irep *irep)
   const size_t record_header_size = sizeof(header);
   int result;
   size_t i, buf_size;
-  uint32_t len;
+  size_t len;
   void *ptr;
   uint8_t *buf;
 
   if (fread(header, record_header_size, 1, fp) == 0) {
     return MRB_DUMP_READ_FAULT;
   }
-  buf_size = bin_to_uint32(&header[0]);
+  buf_size = (size_t)bin_to_uint32(&header[0]);
   if (SIZE_ERROR(buf_size)) {
     return MRB_DUMP_GENERAL_FAILURE;
   }
@@ -553,7 +580,7 @@ read_irep_record_file(mrb_state *mrb, FILE *fp)
   uint8_t header[1 + 4];
   const size_t record_header_size = sizeof(header);
   size_t buf_size, i;
-  uint32_t len;
+  size_t len;
   mrb_irep *irep = NULL;
   void *ptr;
   uint8_t *buf;
@@ -561,7 +588,7 @@ read_irep_record_file(mrb_state *mrb, FILE *fp)
   if (fread(header, record_header_size, 1, fp) == 0) {
     return NULL;
   }
-  buf_size = bin_to_uint32(&header[0]);
+  buf_size = (size_t)bin_to_uint32(&header[0]);
   if (SIZE_ERROR(buf_size)) {
     return NULL;
   }
@@ -600,7 +627,7 @@ mrb_read_irep_file(mrb_state *mrb, FILE* fp)
   int result;
   uint8_t *buf;
   uint16_t crc, crcwk = 0;
-  uint32_t section_size = 0;
+  size_t section_size = 0;
   size_t nbytes;
   struct rite_section_header section_header;
   long fpos;
@@ -657,7 +684,7 @@ mrb_read_irep_file(mrb_state *mrb, FILE* fp)
     if (fread(&section_header, sizeof(struct rite_section_header), 1, fp) == 0) {
       return NULL;
     }
-    section_size = bin_to_uint32(section_header.section_size);
+    section_size = (size_t)bin_to_uint32(section_header.section_size);
 
     if (memcmp(section_header.section_identify, RITE_SECTION_IREP_IDENTIFIER, sizeof(section_header.section_identify)) == 0) {
       fseek(fp, fpos, SEEK_SET);
diff --git a/src/string.c b/src/string.c
index 85a3cc2a7..123a1dcb5 100644
--- a/src/string.c
+++ b/src/string.c
@@ -2067,8 +2067,12 @@ mrb_string_value_cstr(mrb_state *mrb, mrb_value *ptr)
 {
   struct RString *ps = mrb_str_ptr(*ptr);
   char *s = STR_PTR(ps);
+  mrb_int len;
 
-  if (!s || STR_LEN(ps) != strlen(s)) {
+  len = STR_LEN(ps);
+  mrb_assert(len >= 0);
+  mrb_assert((size_t)len <= SIZE_MAX);
+  if (!s || (size_t)len != strlen(s)) {
     mrb_raise(mrb, E_ARGUMENT_ERROR, "string contains null byte");
   }
   return s;