From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2988 invoked by alias); 24 Mar 2004 00:02:49 -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 2981 invoked from network); 24 Mar 2004 00:02:46 -0000 Received: from unknown (HELO localhost.redhat.com) (66.30.197.194) by sources.redhat.com with SMTP; 24 Mar 2004 00:02:46 -0000 Received: from gnu.org (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id 651052B92; Tue, 23 Mar 2004 19:02:45 -0500 (EST) Message-ID: <4060D025.6070601@gnu.org> Date: Wed, 24 Mar 2004 00:02:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-GB; rv:1.4.1) Gecko/20040217 MIME-Version: 1.0 To: Daniel Jacobowitz Cc: gdb-patches@sources.redhat.com Subject: Re: [patch/rfc] signal trampoline frames References: <405E5A09.2050803@gnu.org> <20040323230930.GA23960@nevyn.them.org> In-Reply-To: <20040323230930.GA23960@nevyn.them.org> Content-Type: multipart/mixed; boundary="------------000906050201040906090401" X-SW-Source: 2004-03/txt/msg00546.txt.bz2 This is a multi-part message in MIME format. --------------000906050201040906090401 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-length: 1460 see attached? > >>> +static CORE_ADDR >>> +tramp_frame_start (CORE_ADDR pc, const struct tramp_frame *tramp) >>> +{ >>> + int ti; >>> + /* Search through the trampoline for one that matches the >>> + instruction sequence around PC. */ >>> + for (ti = 0; tramp->insn[ti] != 0; ti++) >>> + { >>> + CORE_ADDR func = pc - tramp->insn_size * ti; >>> + int i; >>> + for (i = 0; 1; i++) >>> + { >>> + bfd_byte buf[sizeof (LONGEST)]; >>> + CORE_ADDR insn; > > > tramp->insn is a ULONGEST. Both of these should probably be ULONGEST > also. changed to ->insn[0] > >>> + if (tramp->insn[i] == 0) >>> + return func; > > > So zeros in tramp->insn mark the end of the sequence? Should document > that, zeros are valid instructions and some bizarre architecture might > use one as a syscall trap. Added TRAMP_SENTINEL_INSN, it _isn't_ zero. >>> + /* If the function has a valid symbol name, it isn't a >>> + trampoline. */ >>> + find_pc_partial_function (pc, &name, NULL, NULL); >>> + if (name != NULL) >>> + return 0; >>> + /* If the function lives in a valid section (even without a starting >>> + point) it isn't a trampoline. */ >>> + if (find_pc_section (pc) != NULL) >>> + return 0; > > > I believe the first check is redundant to the second check; can we have > names without sections? I may be wrong about this, remembering the > problem on IRIX with absolute sections. I don't know. Andrew --------------000906050201040906090401 Content-Type: text/plain; name="diffs" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="diffs" Content-length: 3634 2004-03-23 Andrew Cagney * tramp-frame.h (TRAMP_SENTINEL_INSN): Define, document. * tramp-frame.c: Include "gdb_assert.h". (tramp_frame_start): Use TRAMP_SENTINEL_INSN. (tramp_frame_append): Assert the presence of TRAMP_SENTINEL_INSN. * Makefile.in (tramp-frame.o): Update dependencies. Index: Makefile.in =================================================================== RCS file: /cvs/src/src/gdb/Makefile.in,v retrieving revision 1.529 diff -u -r1.529 Makefile.in --- Makefile.in 23 Mar 2004 14:12:30 -0000 1.529 +++ Makefile.in 23 Mar 2004 23:58:05 -0000 @@ -2449,7 +2449,7 @@ $(regcache_h) tramp-frame.o: tramp-frame.c $(defs_h) $(tramp_frame_h) $(frame_unwind_h) \ $(gdbcore_h) $(symtab_h) $(objfiles_h) $(target_h) $(trad_frame_h) \ - $(frame_base_h) + $(frame_base_h) $(gdb_assert_h) typeprint.o: typeprint.c $(defs_h) $(gdb_obstack_h) $(bfd_h) $(symtab_h) \ $(gdbtypes_h) $(expression_h) $(value_h) $(gdbcore_h) $(command_h) \ $(gdbcmd_h) $(target_h) $(language_h) $(cp_abi_h) $(typeprint_h) \ Index: tramp-frame.c =================================================================== RCS file: /cvs/src/src/gdb/tramp-frame.c,v retrieving revision 1.2 diff -u -r1.2 tramp-frame.c --- tramp-frame.c 23 Mar 2004 14:12:30 -0000 1.2 +++ tramp-frame.c 23 Mar 2004 23:58:06 -0000 @@ -28,6 +28,7 @@ #include "target.h" #include "trad-frame.h" #include "frame-base.h" +#include "gdb_assert.h" struct frame_data { @@ -89,15 +90,15 @@ int ti; /* Search through the trampoline for one that matches the instruction sequence around PC. */ - for (ti = 0; tramp->insn[ti] != 0; ti++) + for (ti = 0; tramp->insn[ti] != TRAMP_SENTINEL_INSN; ti++) { CORE_ADDR func = pc - tramp->insn_size * ti; int i; for (i = 0; 1; i++) { - bfd_byte buf[sizeof (LONGEST)]; + bfd_byte buf[sizeof (tramp->insn[0])]; CORE_ADDR insn; - if (tramp->insn[i] == 0) + if (tramp->insn[i] == TRAMP_SENTINEL_INSN) return func; if (target_read_memory (func + i * tramp->insn_size, buf, tramp->insn_size) != 0) @@ -148,6 +149,15 @@ { struct frame_data *data; struct frame_unwind *unwinder; + int i; + + /* Check that the instruction sequence contains a sentinel. */ + for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++) + { + if (tramp_frame->insn[i] == TRAMP_SENTINEL_INSN) + break; + } + gdb_assert (i < ARRAY_SIZE (tramp_frame->insn)); data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data); unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind); Index: tramp-frame.h =================================================================== RCS file: /cvs/src/src/gdb/tramp-frame.h,v retrieving revision 1.2 diff -u -r1.2 tramp-frame.h --- tramp-frame.h 23 Mar 2004 14:12:30 -0000 1.2 +++ tramp-frame.h 23 Mar 2004 23:58:06 -0000 @@ -39,6 +39,10 @@ /* A trampoline descriptor. */ +/* Magic instruction that to mark the end of the signal trampoline + instruction sequence (zero for the moment). */ +#define TRAMP_SENTINEL_INSN ((LONGEST) -1) + struct tramp_frame { /* The trampoline's entire instruction sequence. Search for this in @@ -47,7 +51,8 @@ one INSN_SIZE instruction. It is also assumed that TRAMP[0] contains the first instruction of the trampoline and hence the address of the instruction matching TRAMP[0] is the trampoline's - "func" address. */ + "func" address. The instruction sequence shall be terminated by + TRAMP_SENTINEL_INSN. */ int insn_size; ULONGEST insn[8]; /* Initialize a trad-frame cache corresponding to the tramp-frame. --------------000906050201040906090401--