vm_core.h (struct rb_iseq_struct): reduce to 296 bytes on 64-bit

Most iseq do not have a catch_table, so avoid needlessly adding
4-8 bytes to the struct for the common case.

Changes from v2:
- iseq_catch_table_size removed, use if (...) for (;...;)

Changes from v1:
- renamed iseq->_catch_table to iseq->catch_table
- iseq_catch_table_bytes: made a static inline function
- iseq_catch_table_size: new function replaces the
  iseq_catch_table_each iterator macro

* iseq.h (struct iseq_catch_table): new flexible array struct
         (iseq_catch_table_bytes): allocated size function
* vm_core.h (struct rb_iseq_struct): uupdate catch_table member
* compile.c (iseq_set_exception_table): update for struct changes
* iseq.c (iseq_free): ditto
* iseq.c (iseq_memsize): ditto
* iseq.c (rb_iseq_disasm): ditto
* iseq.c (iseq_data_to_ary): ditto
* iseq.c (rb_iseq_build_for_ruby2cext): ditto (untested)
* vm.c (vm_exec): ditto
* vm_core.h (struct rb_iseq_struct): ditto
* vm_insnhelper.c (vm_throw): ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46811 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 4 deletions

diff --git a/compile.c b/compile.c
index 6c71a8586f..637e112b05 100644
--- a/compile.c
+++ b/compile.c
@@ -1681,12 +1681,15 @@ iseq_set_exception_table(rb_iseq_t *iseq)
     tlen = (int)RARRAY_LEN(iseq->compile_data->catch_table_ary);
     tptr = RARRAY_CONST_PTR(iseq->compile_data->catch_table_ary);
 
-    iseq->catch_table = tlen ? ALLOC_N(struct iseq_catch_table_entry, tlen) : 0;
-    iseq->catch_table_size = tlen;
+    iseq->catch_table = 0;
+    if (tlen > 0) {
+	iseq->catch_table = xmalloc(iseq_catch_table_bytes(tlen));
+	iseq->catch_table->size = tlen;
+    }
 
-    for (i = 0; i < tlen; i++) {
+    if (iseq->catch_table) for (i = 0; i < iseq->catch_table->size; i++) {
 	ptr = RARRAY_CONST_PTR(tptr[i]);
-	entry = &iseq->catch_table[i];
+	entry = &iseq->catch_table->entries[i];
 	entry->type = (enum catch_type)(ptr[0] & 0xffff);
 	entry->start = label_get_position((LABEL *)(ptr[1] & ~1));
 	entry->end = label_get_position((LABEL *)(ptr[2] & ~1));