Extended mruby binary format

The catch handler table is combined with iseq block.
This is to prevent the structure from growing by adding a field for the
catch handler table to the `mrb_irep` structure.

"iseq block" and "catch handler table":
  [number of catch handler table (2 bytes)]
  [number of byte code (4 bytes)]
  [iseq (any bytes)]
  [catch handlers (multiple of 7 bytes)]

catch handler:
  [catch type (1 byte)]
  [begin offset (2 bytes)]
  [end offset (2 bytes)]
  [target offset (2 bytes)]

catch type: enum mrb_catch_type (0 = rescue, 1 = ensure)
begin offset: Includes the specified instruction address
end offset: Does not include the specified instruction address
target offset: replaces pc with the specified instruction address

This table is not expanded by `read_irep_record_1()`.
The necessary elements are expanded one by one when used.

1 files changed, 32 insertions, 0 deletions

diff --git a/src/dump.c b/src/dump.c
index 6acba12c2..884c44dc6 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -274,12 +274,38 @@ write_syms_block(mrb_state *mrb, const mrb_irep *irep, uint8_t *buf)
 }
 
 static size_t
+get_catch_table_block_size(mrb_state *mrb, const mrb_irep *irep)
+{
+  size_t size = 0;
+
+  size += sizeof(uint16_t); /* number of catch handler */
+  size += (sizeof(struct mrb_irep_catch_hander)) * irep->clen;
+
+  return size;
+}
+
+static ptrdiff_t
+write_catch_table_block(mrb_state *mrb, const mrb_irep *irep, uint8_t *buf)
+{
+  uint8_t *cur = buf;
+  const struct mrb_irep_catch_hander *e = mrb_irep_catch_handler_table(irep);
+  mrb_static_assert1(sizeof(*e) == 7);
+
+  /* irep->clen has already been written before iseq block */
+  memcpy(cur, (const void *)e, sizeof(*e) * irep->clen);
+  cur += sizeof(*e) * irep->clen;
+
+  return cur - buf;
+}
+
+static size_t
 get_irep_record_size_1(mrb_state *mrb, const mrb_irep *irep)
 {
   size_t size = 0;
 
   size += get_irep_header_size(mrb);
   size += get_iseq_block_size(mrb, irep);
+  size += get_catch_table_block_size(mrb, irep);
   size += get_pool_block_size(mrb, irep);
   size += get_syms_block_size(mrb, irep);
   return size;
@@ -314,7 +340,13 @@ write_irep_record(mrb_state *mrb, const mrb_irep *irep, uint8_t *bin, size_t *ir
   }
 
   bin += write_irep_header(mrb, irep, bin);
+  /*
+   * The catch handler table is after iseq block, but the number of
+   * elements is placed before iseq block.
+   */
+  bin += uint16_to_bin(irep->clen, bin);
   bin += write_iseq_block(mrb, irep, bin, flags);
+  bin += write_catch_table_block(mrb, irep, bin);
   bin += write_pool_block(mrb, irep, bin);
   bin += write_syms_block(mrb, irep, bin);