494954 - JS_GetScriptLineExtent() does not returns the right value

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect, P1)

Description

[Franck]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10
Build Identifier: trunk

The following script:
function foo( obj ) {
	
	obj = 1;
	obj = 1;
}

Triggers NewScriptHook with:
New debug.js:1 extent:1 - foo - lvl:1 - ptr:00A7CF68
New debug.js:1 extent:5 -  - lvl:0 - ptr:00A7D170

(printf( "New %s:%d extent:%d - %s - lvl:%d - ptr:%p\n", filename, lineno, JS_GetScriptLineExtent(cx, script), fun ? JS_GetFunctionName(fun):"", script->staticLevel, script );)



Reproducible: Always

Comment 1

[Jason Orendorff [:jorendorff]]

We have a spurious SRC_SETLINE note at the end of the function.

js> dis(foo)
flags: NULL_CLOSURE
main:
00000:  one
00001:  setarg 0
00004:  pop
00005:  one
00006:  setarg 0
00009:  pop
00010:  stop

Source notes:
  0:     0 [   0] setline  lineno 3
  2:     5 [   5] newline 
  3:    10 [   5] setline  lineno 1

Comment 2

[Jason Orendorff [:jorendorff]]

(gdb) f 2
#2  0x08099b61 in js_EmitTree (cx=0x86441d8, cg=0x865dc20, pn=0x865d920) at ../jsemit.cpp:6783
6783	        if (!UpdateLineNumberNotes(cx, cg, pn->pn_pos.end.lineno))
(gdb) p pn->pn_pos
$1 = {begin = {index = 14, lineno = 1}, end = {index = 17, lineno = 1}}

with the stack shown below.

#0  js_NewSrcNote2 (cx=0x86441d8, cg=0x865dc20, type=SRC_SETLINE, offset=1) at ../jsemit.cpp:6906
#1  0x0808d67f in UpdateLineNumberNotes (cx=0x86441d8, cg=0x865dc20, line=1) at ../jsemit.cpp:3535
#2  0x08099b61 in js_EmitTree (cx=0x86441d8, cg=0x865dc20, pn=0x865d920) at ../jsemit.cpp:6783
#3  0x08099c56 in js_EmitFunctionScript (cx=0x86441d8, cg=0x865dc20, body=0x865d920) at ../jsemit.cpp:3498
#4  0x08091a0e in js_EmitTree (cx=0x86441d8, cg=0xbfef4ee8, pn=0x865d880) at ../jsemit.cpp:4297
#5  0x080feadd in JSCompiler::compileScript (cx=0x86441d8, scopeChain=0x8647000, callerFrame=0x0, principals=0x0, tcflags=24576, 
    chars=0x0, length=0, file=0x865d268, filename=0x8655fd0 "crasher.js", lineno=1, source=0x0) at ../jsparse.cpp:896
#6  0x0805673f in JS_CompileFile (cx=0x86441d8, obj=0x8647000, filename=0x8655fd0 "crasher.js") at ../jsapi.cpp:4784
#7  0x08051109 in Load (cx=0x86441d8, obj=0x8647000, argc=1, argv=0x865b270, rval=0xbfef51a0) at ../../shell/js.cpp:890
...

Comment 3

[Brendan Eich [:brendan]]

Attachment: fix

Comment 4

[Brendan Eich [:brendan]]

This should block.

/be

Comment 6

[Brendan Eich [:brendan]]

Fixed in tm:

http://hg.mozilla.org/tracemonkey/rev/e7a08f46b514

/be

Comment 7

[John J. Barton]

How would I succeed at getting more of the line number bugs fixed? For example, 488730

Comment 8

[Brendan Eich [:brendan]]

(In reply to comment #7)
> How would I succeed at getting more of the line number bugs fixed? For example,
> 488730

Get bugs like that in the right component, and cc: peers and owner, for a start. :-/

/be

Comment 9

[Mike Beltzner [:beltzner, not reading bugmail]]

As per comment 4

Comment 10

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/e7a08f46b514

Comment 11

[Robert Sayre]

http://hg.mozilla.org/releases/mozilla-1.9.1/rev/1e46b279b508