From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26701 invoked by alias); 24 Apr 2002 07:09:15 -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 26624 invoked from network); 24 Apr 2002 07:09:14 -0000 Received: from unknown (HELO pizda.ninka.net) (216.101.162.242) by sources.redhat.com with SMTP; 24 Apr 2002 07:09:14 -0000 Received: from localhost (IDENT:davem@localhost.localdomain [127.0.0.1]) by pizda.ninka.net (8.9.3/8.9.3) with ESMTP id XAA26469; Tue, 23 Apr 2002 23:59:51 -0700 Date: Wed, 24 Apr 2002 00:09:00 -0000 Message-Id: <20020423.235951.23032845.davem@redhat.com> To: msnyder@redhat.com Cc: gdb-patches@sources.redhat.com Subject: Re: [RFA] Improve Sparc epilogue analysis From: "David S. Miller" In-Reply-To: <3CC5B3DD.AE14C458@redhat.com> References: <20020420.002304.41086933.davem@redhat.com> <3CC5B3DD.AE14C458@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-SW-Source: 2002-04/txt/msg00917.txt.bz2 From: Michael Snyder Date: Tue, 23 Apr 2002 12:19:57 -0700 No. Examine prologue serves two roles. One is simply to skip to the end of the prologue, but the other is to actually determine where the registers are saved by the prologue. You've short-circuited the second usage. Your idea is sound, though -- you've just implemented it in the wrong place. Instead of modifying examine_prologue, how about if you modify sparc_gdbarch_skip_prologue? Right. There is even extra confusion arising from the fact that we have two functions for the same thing. These are sparc_skip_prologue and sparc_gdbarch_skip_prologue. I killed the latter, and we can "static" the former when all the sparc targets are multi-arch'd. How does this revised patch look? 2002-04-23 David S. Miller * sparc-tdep.c (sparc_gdbarch_skip_prologue): Kill, duplicates sparc_skip_prologue. (sparc_skip_prologue): Kill frameless_p arg, and use line number information to find prologue when possible. (sparc_prologue_frameless_p): Use line number information. (sparc_gdbarch_init): Update set_gdbarch_skip_prologue call. (sparc_init_extra_frame_info): Use sparc_skip_prologue to find prologue bounds instead of looking at line number info by hand. * config/sparc/tm-sparc.h (sparc_skip_prologue): Update for killed second argument. (SKIP_PROLOGUE): Likewise. --- ./config/sparc/tm-sparc.h.~1~ Sun Apr 21 19:18:59 2002 +++ ./config/sparc/tm-sparc.h Tue Apr 23 22:38:43 2002 @@ -250,8 +250,8 @@ extern int sparc_intreg_size (void); /* Advance PC across any function entry prologue instructions to reach some "real" code. */ -extern CORE_ADDR sparc_skip_prologue (CORE_ADDR, int); -#define SKIP_PROLOGUE(PC) sparc_skip_prologue (PC, 0) +extern CORE_ADDR sparc_skip_prologue (CORE_ADDR); +#define SKIP_PROLOGUE(PC) sparc_skip_prologue (PC) /* Immediately after a function call, return the saved pc. Can't go through the frames for this because on some machines --- ./sparc-tdep.c.~1~ Sun Apr 21 20:51:34 2002 +++ ./sparc-tdep.c Tue Apr 23 23:00:46 2002 @@ -279,6 +279,8 @@ struct frame_extra_info int sp_offset; }; +CORE_ADDR sparc_skip_prologue (CORE_ADDR); + /* Call this for each newly created frame. For SPARC, we need to calculate the bottom of the frame, and do some extra work if the prologue has been generated via the -mflat option to GCC. In @@ -393,25 +395,20 @@ sparc_init_extra_frame_info (int fromlea to the current value of the stack pointer and set the in_prologue flag. */ CORE_ADDR addr; - struct symtab_and_line sal; - sal = find_pc_line (prologue_start, 0); - if (sal.line == 0) /* no line info, use PC */ - prologue_end = fi->pc; - else if (sal.end < prologue_end) - prologue_end = sal.end; + prologue_end = sparc_skip_prologue (prologue_start); if (fi->pc < prologue_end) { - for (addr = prologue_start; addr < fi->pc; addr += 4) + for (addr = fi->pc; addr < prologue_end; addr += 4) { insn = read_memory_integer (addr, 4); if (X_OP (insn) == 2 && X_OP3 (insn) == 0x3c) break; /* SAVE seen, stop searching */ } - if (addr >= fi->pc) + if (addr < prologue_end) { fi->extra_info->in_prologue = 1; - fi->frame = read_register (SP_REGNUM); + fi->frame = read_sp (); } } } @@ -685,18 +682,50 @@ examine_prologue (CORE_ADDR start_pc, in return pc; } +/* Advance PC across any function entry prologue instructions to reach + some "real" code. */ + CORE_ADDR -sparc_skip_prologue (CORE_ADDR start_pc, int frameless_p) +sparc_skip_prologue (CORE_ADDR start_pc) { - return examine_prologue (start_pc, frameless_p, NULL, NULL); + struct symtab_and_line sal; + CORE_ADDR func_start, func_end; + + /* This is the preferred method, find the end of the prologue by + using the debugging information. */ + if (find_pc_partial_function (start_pc, NULL, &func_start, &func_end)) + { + sal = find_pc_line (func_start, 0); + + if (sal.end < func_end + && start_pc <= sal.end) + return sal.end + } + + /* Oh well, examine the code by hand. */ + return examine_prologue (start_pc, 0, NULL, NULL); } /* Is the prologue at IP frameless? */ int -sparc_prologue_frameless_p (CORE_ADDR ip) +sparc_prologue_frameless_p (CORE_ADDR start_pc) { - return ip == sparc_skip_prologue (ip, 1); + struct symtab_and_line sal; + CORE_ADDR func_start, func_end; + + /* This is the preferred method, find the end of the prologue by + using the debugging information. */ + if (find_pc_partial_function (start_pc, NULL, &func_start, &func_end)) + { + sal = find_pc_line (func_start, 0); + + if (sal.end < func_end + && start_pc <= sal.end) + return start_pc == sal.end; + } + + return start_pc == examine_prologue (start_pc, 1, NULL, NULL); } /* Check instruction at ADDR to see if it is a branch. @@ -2784,15 +2813,6 @@ sparc64_register_byte (int regno) return 64 * 8 + (regno - 80) * 8; } -/* Advance PC across any function entry prologue instructions to reach - some "real" code. */ - -static CORE_ADDR -sparc_gdbarch_skip_prologue (CORE_ADDR ip) -{ - return examine_prologue (ip, 0, NULL, NULL); -} - /* Immediately after a function call, return the saved pc. Can't go through the frames for this because on some machines the new frame is not set up until the new function executes @@ -2993,7 +3013,7 @@ sparc_gdbarch_init (struct gdbarch_info set_gdbarch_saved_pc_after_call (gdbarch, sparc_saved_pc_after_call); set_gdbarch_prologue_frameless_p (gdbarch, sparc_prologue_frameless_p); set_gdbarch_short_bit (gdbarch, 2 * TARGET_CHAR_BIT); - set_gdbarch_skip_prologue (gdbarch, sparc_gdbarch_skip_prologue); + set_gdbarch_skip_prologue (gdbarch, sparc_skip_prologue); set_gdbarch_sp_regnum (gdbarch, SPARC_SP_REGNUM); set_gdbarch_use_generic_dummy_frames (gdbarch, 0); set_gdbarch_write_pc (gdbarch, generic_target_write_pc);