From a54a3df32c379a6953664f1d9241c731066915ec Mon Sep 17 00:00:00 2001
From: dearblue <dearblue@users.osdn.me>
Date: Sun, 24 May 2020 00:19:04 +0900
Subject: 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.
---
 src/dump.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

(limited to 'src/dump.c')

diff --git a/src/dump.c b/src/dump.c
index 6acba12c2..884c44dc6 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -273,6 +273,31 @@ write_syms_block(mrb_state *mrb, const mrb_irep *irep, uint8_t *buf)
   return cur - 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)
 {
@@ -280,6 +305,7 @@ get_irep_record_size_1(mrb_state *mrb, const mrb_irep *irep)
 
   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);
 
-- 
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