Subj : Re: problems with error reporting
To   : sctrasca
From : Brendan Eich
Date : Tue Jun 21 2005 04:44 pm

Silviu Trasca wrote:
> Hi,
> I'm embedding SpiderMonkey in my app and have problems (invalid memory 
> reads) with error reporting for lines of code greater than 256 
> characters. I'm using an error  handler similar with the one in js/js.c 
> . I was able to reproduce the problem with "js" shell only (see the 
> valgrind output bellow). SpiderMonkey is compiled in thread safe mode, 
> on FC3.
> 
> Thanks,
> Silviu
> 
> 
> [silviu@home-tx0275arsq js]$ valgrind --tool=memcheck ./js
> ==10403== Memcheck, a memory error detector for x86-linux.
> ==10403== Copyright (C) 2002-2004, and GNU GPL'd, by Julian Seward et al.
> ==10403== Using valgrind-2.2.0, a program supervision framework for 
> x86-linux.
> ==10403== Copyright (C) 2000-2004, and GNU GPL'd, by Julian Seward et al.
> ==10403== For more details, rerun with: -v
> ==10403==
> js>MM_preloadImages('/images/nav_catalog_f2.gif','/images/nav_new_f2.gif','/images/nav_acad_f2.gif','/images/nav_about_f2.gif','/images/top_contact_on.gif,'/images/top_booksellers_on.gif,'/images/top_map_on.gif,'/images/top_cart_on.gif,'/images/top_home_on.gif);
> 1: SyntaxError: unterminated string literal:
> 1: if);
> 1: ......==10403== Invalid read of size 1
> ==10403== at 0x804A880: my_ErrorReporter (in /home/silviu/projects/js/js)


Exactly what line in my_ErrorReporter?  I have single-stepped through in 
gdb and see no invalid loads (memory reads).

/be


> ==10403== by 0x8077AC4: js_ReportUncaughtException (in 
> /home/silviu/projects/js/js)
> ==10403== by 0x804E563: JS_CompileScript (in /home/silviu/projects/js/js)
> ==10403== by 0x8049407: Process (in /home/silviu/projects/js/js)
> ==10403== Address 0x1B969986 is 0 bytes after a block of size 6 alloc'd
> ==10403== at 0x1B902A90: malloc (vg_replace_malloc.c:131)
> ==10403== by 0x80B9F90: js_GetStringBytes (in /home/silviu/projects/js/js)
> ==10403== by 0x804F45D: JS_GetStringBytes (in /home/silviu/projects/js/js)
> ==10403== by 0x80ABEB4: js_ReportCompileErrorNumber (in
> /home/silviu/projects/js/js)
> ...................................................................................................................................................................................................................................^
> js>
>

.