From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10752 invoked by alias); 5 Feb 2003 22:26:25 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 10745 invoked from network); 5 Feb 2003 22:26:24 -0000 Received: from unknown (HELO crack.them.org) (65.125.64.184) by 172.16.49.205 with SMTP; 5 Feb 2003 22:26:24 -0000 Received: from nevyn.them.org ([66.93.61.169] ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 18gZss-00030m-00; Wed, 05 Feb 2003 18:27:19 -0600 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 18gXzu-0007g0-00; Wed, 05 Feb 2003 17:26:26 -0500 Date: Wed, 05 Feb 2003 22:26:00 -0000 From: Daniel Jacobowitz To: Elena Zannoni Cc: gdb-patches@sources.redhat.com Subject: Re: RFA: Fix a big memory leak reading minimal symbols Message-ID: <20030205222626.GA28452@nevyn.them.org> Mail-Followup-To: Elena Zannoni , gdb-patches@sources.redhat.com References: <20030126191411.GA1824@nevyn.them.org> <15937.26495.326748.558348@localhost.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15937.26495.326748.558348@localhost.redhat.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-02/txt/msg00201.txt.bz2 On Wed, Feb 05, 2003 at 02:35:27PM -0500, Elena Zannoni wrote: > Daniel Jacobowitz writes: > > This patch is good for a whopping 13% (7MB) of memory usage when reading in > > all of mozilla's minimal symbols (stabs). The control flow looks like this > > right now: > > - init_minimal_symbol_collection in elf_symfile_read > > - install_minimal_symbols in elfstab_build_psymtabs. Presumably added so > > that we don't lose the minimal symbols above. > > right, elfstab_build_psymtab is called by elf_symfile_read, after > init_minimal_symbol_collection. > > > - dbx_symfile_read contains a complete init_minimal_symbol_collection / > > install_minimal_symbols pair, which generally finds no minimal symbols > > in ELF. > > elfstab_build_psymtab calls dbx_symfile_read. > > > - install_minimal_symbols and matching cleanup in elf_symfile_read. > > > > at the end. > > > Only problem is, that second init_minimal_symbol_collection call zeroed out > > the bunch pointer. We've installed them but we never free them, so they > > just sit around wasting memory. > > OK, I see the problem in this sequence. There is another 'stray' call > to install_minimal_symbols, in stabsect_build_psymtab, and this > function also calls dbx_symfile_read. The sequence is the same. So the > problem should occur there as well. > stabsect_build_psymtab is called by som_symfile_read. And by nlm_symfile_read too. > > This patch arranges for all calls to init_minimal_symbol_collection in ELF > > targets to be paired with matching cleanups and install_minimal_symbols > > calls. This means that elfmdebug_build_psymtabs gets its own pair instead > > of relying on elf_symfile_read, and that elf_symfile_read installs its own > > minimal symbols much earlier. > > How does elfstab_build_psymtabs get invoked from mdebug? Oh, it > doesn't. It gets invoked after the mdebug stuff is over. > > I see, you are adding pairs of install+cleanup to the mdebug psymtab > builder, i.e. each piece is self-sufficient. For the stabs psymtab > builder the appropriate steps are done in dbx_symfile_read already. Right. Each reader that wants to do this, should do it itself, since they don't nest. > let's see all the symtabs builders: > > coffstab_build_psymtabs -> calls dbx_symfile_read ok Ugh. This is OK but its caller isn't; coff_symtab_read has some minimal symbols outstanding when it calls coffstab_build_psymtabs. Fixed, but I don't have any tests for COFF set up. > elfstab_build_psymtabs -> you fixed ok > stabsect_build_psymtabs -> dubious Fixed, in both callers. > dwarf2_build_psymtabs -> no need > dwarf_build_psymtabs -> don't care > hpread_build_psymtabs -> no clue, messy. I think it does it directly. > mdebug_build_psymtabs -> you fixed ok > > if the table above makes sense, then can you verify/fix the dubious case? How's this look? New changes in coff_symfile_read, nlm_symfile_read, som_symfile_read, and stabsect_build_psymtabs. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer 2002-02-05 Daniel Jacobowitz * coffread.c (coff_symfile_read): Clean up minimal symbols earlier. * dbxread.c (elfstab_build_psymtabs): Don't call install_minimal_symbols. (stabsect_build_psymtabs): Likewise. * elfread.c (elf_symfile_read): Call install_minimal_symbols earlier. * somread.c (som_symfile_read): Call install_minimal_symbols and do_cleanups earlier. * nlmread.c (nlm_symfile_read): Likewise. * mdebugread.c (elfmdebug_build_psymtabs): Call install_minimal_symbols and make appropriate cleanups. Index: coffread.c =================================================================== RCS file: /cvs/src/src/gdb/coffread.c,v retrieving revision 1.33 diff -u -p -r1.33 coffread.c --- coffread.c 4 Feb 2003 18:07:00 -0000 1.33 +++ coffread.c 5 Feb 2003 22:22:13 -0000 @@ -515,7 +515,7 @@ coff_symfile_read (struct objfile *objfi unsigned int num_symbols; int symtab_offset; int stringtab_offset; - struct cleanup *back_to; + struct cleanup *back_to, *cleanup_minimal_symbols; int stabstrsize; int len; char * target; @@ -595,7 +595,7 @@ coff_symfile_read (struct objfile *objfi error ("\"%s\": can't get string table", name); init_minimal_symbol_collection (); - make_cleanup_discard_minimal_symbols (); + cleanup_minimal_symbols = make_cleanup_discard_minimal_symbols (); /* Now that the executable file is positioned at symbol table, process it and define symbols accordingly. */ @@ -615,6 +615,9 @@ coff_symfile_read (struct objfile *objfi minimal symbols for this objfile. */ install_minimal_symbols (objfile); + + /* Free the installed minimal symbol data. */ + do_cleanups (cleanup_minimal_symbols); bfd_map_over_sections (abfd, coff_locate_sections, (void *) info); Index: dbxread.c =================================================================== RCS file: /cvs/src/src/gdb/dbxread.c,v retrieving revision 1.41 diff -u -p -r1.41 dbxread.c --- dbxread.c 31 Jan 2003 19:22:17 -0000 1.41 +++ dbxread.c 5 Feb 2003 22:22:13 -0000 @@ -3555,7 +3555,6 @@ elfstab_build_psymtabs (struct objfile * buildsym_new_init (); free_header_files (); init_header_files (); - install_minimal_symbols (objfile); processing_acc_compilation = 1; @@ -3567,7 +3566,10 @@ elfstab_build_psymtabs (struct objfile * /* In an elf file, we've already installed the minimal symbols that came from the elf (non-stab) symbol table, so always act like an - incremental load here. */ + incremental load here. dbx_symfile_read should not generate any new + minimal symbols, since we will have already read the ELF dynamic symbol + table and normal symbol entries won't be in the ".stab" section; but in + case it does, it will install them itself. */ dbx_symfile_read (objfile, 0); if (back_to) @@ -3649,7 +3651,6 @@ stabsect_build_psymtabs (struct objfile buildsym_new_init (); free_header_files (); init_header_files (); - install_minimal_symbols (objfile); /* Now, do an incremental load */ Index: elfread.c =================================================================== RCS file: /cvs/src/src/gdb/elfread.c,v retrieving revision 1.30 diff -u -p -r1.30 elfread.c --- elfread.c 31 Jan 2003 19:22:18 -0000 1.30 +++ elfread.c 5 Feb 2003 22:22:14 -0000 @@ -542,6 +542,15 @@ elf_symfile_read (struct objfile *objfil elf_symtab_read (objfile, 1); + /* Install any minimal symbols that have been collected as the current + minimal symbols for this objfile. The debug readers below this point + should not generate new minimal symbols; if they do it's their + responsibility to install them. "mdebug" appears to be the only one + which will do this. */ + + install_minimal_symbols (objfile); + do_cleanups (back_to); + /* Now process debugging information, which is contained in special ELF sections. */ @@ -611,13 +620,6 @@ elf_symfile_read (struct objfile *objfil if (DWARF2_BUILD_FRAME_INFO_P ()) DWARF2_BUILD_FRAME_INFO(objfile); - - /* Install any minimal symbols that have been collected as the current - minimal symbols for this objfile. */ - - install_minimal_symbols (objfile); - - do_cleanups (back_to); } /* This cleans up the objfile's sym_stab_info pointer, and the chain of Index: mdebugread.c =================================================================== RCS file: /cvs/src/src/gdb/mdebugread.c,v retrieving revision 1.40 diff -u -p -r1.40 mdebugread.c --- mdebugread.c 4 Feb 2003 18:07:01 -0000 1.40 +++ mdebugread.c 5 Feb 2003 22:22:15 -0000 @@ -4808,6 +4808,14 @@ elfmdebug_build_psymtabs (struct objfile { bfd *abfd = objfile->obfd; struct ecoff_debug_info *info; + struct cleanup *back_to; + + /* FIXME: It's not clear whether we should be getting minimal symbol + information from .mdebug in an ELF file, or whether we will. + Re-initialize the minimal symbol reader in case we do. */ + + init_minimal_symbol_collection (); + back_to = make_cleanup_discard_minimal_symbols (); info = ((struct ecoff_debug_info *) obstack_alloc (&objfile->psymbol_obstack, @@ -4818,6 +4826,9 @@ elfmdebug_build_psymtabs (struct objfile bfd_errmsg (bfd_get_error ())); mdebug_build_psymtabs (objfile, swap, info); + + install_minimal_symbols (objfile); + do_cleanups (back_to); } Index: nlmread.c =================================================================== RCS file: /cvs/src/src/gdb/nlmread.c,v retrieving revision 1.9 diff -u -p -r1.9 nlmread.c --- nlmread.c 2 Dec 2001 22:38:23 -0000 1.9 +++ nlmread.c 5 Feb 2003 22:22:15 -0000 @@ -190,6 +190,12 @@ nlm_symfile_read (struct objfile *objfil nlm_symtab_read (abfd, offset, objfile); + /* Install any minimal symbols that have been collected as the current + minimal symbols for this objfile. */ + + install_minimal_symbols (objfile); + do_cleanups (back_to); + stabsect_build_psymtabs (objfile, mainline, ".stab", ".stabstr", ".text"); @@ -204,13 +210,6 @@ nlm_symfile_read (struct objfile *objfil /* FIXME: We could locate and read the optional native debugging format here and add the symbols to the minimal symbol table. */ - - /* Install any minimal symbols that have been collected as the current - minimal symbols for this objfile. */ - - install_minimal_symbols (objfile); - - do_cleanups (back_to); } Index: somread.c =================================================================== RCS file: /cvs/src/src/gdb/somread.c,v retrieving revision 1.16 diff -u -p -r1.16 somread.c --- somread.c 19 Jan 2003 04:06:46 -0000 1.16 +++ somread.c 5 Feb 2003 22:22:15 -0000 @@ -353,6 +353,14 @@ som_symfile_read (struct objfile *objfil som_symtab_read (abfd, objfile, objfile->section_offsets); + /* Install any minimal symbols that have been collected as the current + minimal symbols for this objfile. + Further symbol-reading is done incrementally, file-by-file, + in a step known as "psymtab-to-symtab" expansion. hp-symtab-read.c + contains the code to do the actual DNTT scanning and symtab building. */ + install_minimal_symbols (objfile); + do_cleanups (back_to); + /* Now read information from the stabs debug sections. This is a no-op for SOM. Perhaps it is intended for some kind of mixed STABS/SOM @@ -366,16 +374,8 @@ som_symfile_read (struct objfile *objfil together with a scan of the GNTT. See hp-psymtab-read.c. */ hpread_build_psymtabs (objfile, mainline); - /* Install any minimal symbols that have been collected as the current - minimal symbols for this objfile. - Further symbol-reading is done incrementally, file-by-file, - in a step known as "psymtab-to-symtab" expansion. hp-symtab-read.c - contains the code to do the actual DNTT scanning and symtab building. */ - install_minimal_symbols (objfile); - /* Force hppa-tdep.c to re-read the unwind descriptors. */ objfile->obj_private = NULL; - do_cleanups (back_to); } /* Initialize anything that needs initializing when a completely new symbol