Currently the emitter for post-increment bytecodes explicitly reserve an extra stack slot for GC roots via increasing stackMaxDepth if necessary. A similar reservation would be necessary for enditer bytecode to fix bug 349326. There I plan to use an extra slot to save an exception thrown from for-in loop when executing the iterator. Thus I suggest to extend JSCodeSpec with a field indicating extra temporary slots that the bytecode may need and account for it with a generic code in UpdateDepth from jsemit.c.

The patch adds ntmps to JSCodeSpec and update jsopcode.tbl to insert another column to OPDEF macro. The patch always uses 0 for extra temporary slots and does not touch post-increment generation code as I plan to do that in a separated bug. For greater readability in jsopcode.tbl I grouped the stack-related numbers without spaces as in: OPDEF(JSOP_PUSH, 1, "push", NULL, 1, 0,1,0, 0, JOF_BYTE) I also considered writing OPDEF as OPDEF(JSOP_PUSH, 1, "push", NULL, 1, ST(0,1,0), 0, JOF_BYTE) where ST macro would be defined only when defining js_CodeSpec. But that, although very readable, makes jsopcode.tbl source even wider. The patch also always uses explicit strings when naming bytecode in OPDEF like "null" instead of refering to js_null_str as such names is used only in DEBUG-only dissembling routines.

Comment on attachment 266041 [details] [diff] [review] implementation v1 Does bitfield init work on MSVC? I don't see any non-zero ntmps entries in jsopcode.tbl yet -- how many will there be? Could be overkill if a format flag could be used instead. /be

The patch adds a new format flag to use with ops that needs an extra stack slot for rooting. In the patch I changed JOF constants to use (1<<offset) for better readability.

Comment on attachment 266981 [details] [diff] [review] implementation v2 Looks ok. Nits: * Traditional name is _SHIFT, not _LOG (maybe _LOG2 as runner-up to _SHIFT). * JS_BIT(n) is a bit longer (three chars, vs. "1<<") but avoids uint vs. int and 16-bit int historical concerns. No jsopcode.tbl patch yet? /be

Addressing the nits: I can not use JS_BIT since the code has: #define JOF_NAME (1U<<4) /* name operation */ #define JOF_PROP (2U<<4) /* obj.prop operation */ #define JOF_ELEM (3U<<4) /* obj[index] operation */ #define JOF_XMLNAME (4U<<4) /* XML name: *, a::b, @a, @a::b, etc. */ #define JOF_VARPROP (5U<<4) /* x.prop for arg, var, or local x */ #define JOF_MODEMASK (7U<<4) /* mask for above addressing modes */ I.e. I need number << shift and JS_BIT hives only 1 << shift. But to make numbers unsigned I added the U prefix.

(In reply to comment #4) > > No jsopcode.tbl patch yet? The post++/// changes will be done in bug 383188 and enditer starts to use the JOF_TMPSLOT in bug 349326.

Comment on attachment 267186 [details] [diff] [review] implementation v3 Looks good, thanks. /be

I committed the patch from comment 5 to the trunk: Checking in jsemit.c; /cvsroot/mozilla/js/src/jsemit.c,v <-- jsemit.c new revision: 3.253; previous revision: 3.252 done Checking in jsopcode.h; /cvsroot/mozilla/js/src/jsopcode.h,v <-- jsopcode.h new revision: 3.48; previous revision: 3.47 done