Re: [RFA] arm_scan_prologue: accept strh and strb as well as str

Michael Snyder
2002-05-08T22:41:58Z

Michael Snyder wrote:
>
> Richard Earnshaw wrote:
> >
> > > [sorry for the empty reply]
> > > OK -- I'd be glad to do that. Could you possibly
> > > provide me an example to work from?
> >
> > Below.
> >
> > >
> > > arm_scan_prologue is easy, since it accepts prologue instructions
> > > in any order, but arm_skip_prologue imposes an ordering on them.
> > > I would REALLY like to merge these two functions. In fact I started
> > > to, but then got busy with other things.
> >
> > Go for it...
>
> OK, how do you like the attached?
>
> Also, Andrew and I have been discussing whether the saved arg regs
> should actually be added to the frame-saved-regs. If we decide that
> they should, may I have your pre-approval to make that change?
>
> Thanks,
> Michael

Err, sorry, I should have mentioned that there are a few more
trivial white-space changes in here too. Sloppy of me. Forgot
they were there.

> ------------------------------------------------------------------------
> 2002-04-25 Michael Snyder <msnyder@redhat.com>
>
> * arm-tdep.c (arm_scan_prologue): Accept strb r(0123),[r11,#-nn],
> strh r(0123),[r11,#-nn], str r(0123),[r11,#-nn], as well as
> strb r(0123),[sp,#nn], strh r(0123),[sp,#nn] and
> str r(0123),[sp,#nn].
> (arm_skip_prologue): Ditto. Also make disassembly
> order-independent by placing it in a loop.
>
> Index: arm-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/arm-tdep.c,v
> retrieving revision 1.57
> diff -p -r1.57 arm-tdep.c
> *** arm-tdep.c 1 May 2002 00:57:51 -0000 1.57
> --- arm-tdep.c 8 May 2002 22:31:53 -0000
> *************** arm_skip_prologue (CORE_ADDR pc)
> *** 417,423 ****
> {
> unsigned long inst;
> CORE_ADDR skip_pc;
> ! CORE_ADDR func_addr, func_end;
> char *func_name;
> struct symtab_and_line sal;
>
> --- 417,423 ----
> {
> unsigned long inst;
> CORE_ADDR skip_pc;
> ! CORE_ADDR func_addr, func_end = 0;
> char *func_name;
> struct symtab_and_line sal;
>
> *************** arm_skip_prologue (CORE_ADDR pc)
> *** 444,517 ****
>
> /* Can't find the prologue end in the symbol table, try it the hard way
> by disassembling the instructions. */
> - skip_pc = pc;
> - inst = read_memory_integer (skip_pc, 4);
> - /* "mov ip, sp" is no longer a required part of the prologue. */
> - if (inst == 0xe1a0c00d) /* mov ip, sp */
> - {
> - skip_pc += 4;
> - inst = read_memory_integer (skip_pc, 4);
> - }
>
> ! /* Some prologues begin with "str lr, [sp, #-4]!". */
> ! if (inst == 0xe52de004) /* str lr, [sp, #-4]! */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
>
> ! if ((inst & 0xfffffff0) == 0xe92d0000) /* stmfd sp!,{a1,a2,a3,a4} */
> {
> - skip_pc += 4;
> inst = read_memory_integer (skip_pc, 4);
> - }
>
> ! if ((inst & 0xfffff800) == 0xe92dd800) /* stmfd sp!,{fp,ip,lr,pc} */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
>
> ! /* Any insns after this point may float into the code, if it makes
> ! for better instruction scheduling, so we skip them only if we
> ! find them, but still consider the function to be frame-ful. */
> !
> ! /* We may have either one sfmfd instruction here, or several stfe
> ! insns, depending on the version of floating point code we
> ! support. */
> ! if ((inst & 0xffbf0fff) == 0xec2d0200) /* sfmfd fn, <cnt>, [sp]! */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
> ! else
> ! {
> ! while ((inst & 0xffff8fff) == 0xed6d0103) /* stfe fn, [sp, #-12]! */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
> ! }
>
> ! if ((inst & 0xfffff000) == 0xe24cb000) /* sub fp, ip, #nn */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
>
> ! if ((inst & 0xfffff000) == 0xe24dd000) /* sub sp, sp, #nn */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> ! }
>
> ! while ((inst & 0xffffcfc0) == 0xe50b0000) /* str r(0123), [r11, #-nn] */
> ! {
> ! skip_pc += 4;
> ! inst = read_memory_integer (skip_pc, 4);
> }
>
> ! return skip_pc;
> }
>
> /* *INDENT-OFF* */
> --- 444,506 ----
>
> /* Can't find the prologue end in the symbol table, try it the hard way
> by disassembling the instructions. */
>
> ! /* Like arm_scan_prologue, stop no later than pc + 64. */
> ! if (func_end == 0 || func_end > pc + 64)
> ! func_end = pc + 64;
>
> ! for (skip_pc = pc; skip_pc < func_end; skip_pc += 4)
> {
> inst = read_memory_integer (skip_pc, 4);
>
> ! /* "mov ip, sp" is no longer a required part of the prologue. */
> ! if (inst == 0xe1a0c00d) /* mov ip, sp */
> ! continue;
>
> ! /* Some prologues begin with "str lr, [sp, #-4]!". */
> ! if (inst == 0xe52de004) /* str lr, [sp, #-4]! */
> ! continue;
>
> ! if ((inst & 0xfffffff0) == 0xe92d0000) /* stmfd sp!,{a1,a2,a3,a4} */
> ! continue;
>
> ! if ((inst & 0xfffff800) == 0xe92dd800) /* stmfd sp!,{fp,ip,lr,pc} */
> ! continue;
>
> ! /* Any insns after this point may float into the code, if it makes
> ! for better instruction scheduling, so we skip them only if we
> ! find them, but still consider the function to be frame-ful. */
> !
> ! /* We may have either one sfmfd instruction here, or several stfe
> ! insns, depending on the version of floating point code we
> ! support. */
> ! if ((inst & 0xffbf0fff) == 0xec2d0200) /* sfmfd fn, <cnt>, [sp]! */
> ! continue;
> !
> ! if ((inst & 0xffff8fff) == 0xed6d0103) /* stfe fn, [sp, #-12]! */
> ! continue;
> !
> ! if ((inst & 0xfffff000) == 0xe24cb000) /* sub fp, ip, #nn */
> ! continue;
> !
> ! if ((inst & 0xfffff000) == 0xe24dd000) /* sub sp, sp, #nn */
> ! continue;
> !
> ! if ((inst & 0xffffc000) == 0xe54b0000 || /* strb r(0123),[r11,#-nn] */
> ! (inst & 0xffffc0f0) == 0xe14b00b0 || /* strh r(0123),[r11,#-nn] */
> ! (inst & 0xffffc000) == 0xe50b0000) /* str r(0123),[r11,#-nn] */
> ! continue;
> !
> ! if ((inst & 0xffffc000) == 0xe5cd0000 || /* strb r(0123),[sp,#nn] */
> ! (inst & 0xffffc0f0) == 0xe1cd00b0 || /* strh r(0123),[sp,#nn] */
> ! (inst & 0xffffc000) == 0xe58d0000) /* str r(0123),[sp,#nn] */
> ! continue;
> !
> ! /* Un-recognized instruction; stop scanning. */
> ! break;
> }
>
> ! return skip_pc; /* End of prologue */
> }
>
> /* *INDENT-OFF* */
> *************** thumb_scan_prologue (struct frame_info *
> *** 597,603 ****
> whether to save LR (R14). */
> mask = (insn & 0xff) | ((insn & 0x100) << 6);
>
> ! /* Calculate offsets of saved R0-R7 and LR. */
> for (regno = ARM_LR_REGNUM; regno >= 0; regno--)
> if (mask & (1 << regno))
> {
> --- 586,592 ----
> whether to save LR (R14). */
> mask = (insn & 0xff) | ((insn & 0x100) << 6);
>
> ! /* Calculate offsets of saved R0-R7 and LR. */
> for (regno = ARM_LR_REGNUM; regno >= 0; regno--)
> if (mask & (1 << regno))
> {
> *************** thumb_scan_prologue (struct frame_info *
> *** 611,617 ****
> else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR
> sub sp, #simm */
> {
> ! if ((findmask & 1) == 0) /* before push? */
> continue;
> else
> findmask |= 4; /* add/sub sp found */
> --- 600,606 ----
> else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR
> sub sp, #simm */
> {
> ! if ((findmask & 1) == 0) /* before push? */
> continue;
> else
> findmask |= 4; /* add/sub sp found */
> *************** arm_scan_prologue (struct frame_info *fi
> *** 857,863 ****
> Be careful, however, and if it doesn't look like a prologue,
> don't try to scan it. If, for instance, a frameless function
> begins with stmfd sp!, then we will tell ourselves there is
> ! a frame, which will confuse stack traceback, as well ad"finish"
> and other operations that rely on a knowledge of the stack
> traceback.
>
> --- 846,852 ----
> Be careful, however, and if it doesn't look like a prologue,
> don't try to scan it. If, for instance, a frameless function
> begins with stmfd sp!, then we will tell ourselves there is
> ! a frame, which will confuse stack traceback, as well as "finish"
> and other operations that rely on a knowledge of the stack
> traceback.
>
> *************** arm_scan_prologue (struct frame_info *fi
> *** 870,876 ****
> [Note further: The "mov ip,sp" only seems to be missing in
> frameless functions at optimization level "-O2" or above,
> in which case it is often (but not always) replaced by
> ! "str lr, [sp, #-4]!". - Michael Snyder, 2002-04-23] */
>
> sp_offset = fp_offset = 0;
>
> --- 859,865 ----
> [Note further: The "mov ip,sp" only seems to be missing in
> frameless functions at optimization level "-O2" or above,
> in which case it is often (but not always) replaced by
> ! "str lr, [sp, #-4]!". - Michael Snyder, 2002-04-23] */
>
> sp_offset = fp_offset = 0;
>
> *************** arm_scan_prologue (struct frame_info *fi
> *** 904,910 ****
> fi->saved_regs[regno] = sp_offset;
> }
> }
> ! else if ((insn & 0xffffcfc0) == 0xe50b0000) /* str rx, [r11, -n] */
> {
> /* No need to add this to saved_regs -- it's just an arg reg. */
> continue;
> --- 893,908 ----
> fi->saved_regs[regno] = sp_offset;
> }
> }
> ! else if ((insn & 0xffffc000) == 0xe54b0000 || /* strb rx,[r11,#-n] */
> ! (insn & 0xffffc0f0) == 0xe14b00b0 || /* strh rx,[r11,#-n] */
> ! (insn & 0xffffc000) == 0xe50b0000) /* str rx,[r11,#-n] */
> ! {
> ! /* No need to add this to saved_regs -- it's just an arg reg. */
> ! continue;
> ! }
> ! else if ((insn & 0xffffc000) == 0xe5cd0000 || /* strb rx,[sp,#n] */
> ! (insn & 0xffffc0f0) == 0xe1cd00b0 || /* strh rx,[sp,#n] */
> ! (insn & 0xffffc000) == 0xe58d0000) /* str rx,[sp,#n] */
> {
> /* No need to add this to saved_regs -- it's just an arg reg. */
> continue;
> *************** arm_scan_prologue (struct frame_info *fi
> *** 960,966 ****
> }
> else if ((insn & 0xf0000000) != 0xe0000000)
> break; /* Condition not true, exit early */
> ! else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
> break; /* Don't scan past a block load */
> else
> /* The optimizer might shove anything into the prologue,
> --- 958,964 ----
> }
> else if ((insn & 0xf0000000) != 0xe0000000)
> break; /* Condition not true, exit early */
> ! else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
> break; /* Don't scan past a block load */
> else
> /* The optimizer might shove anything into the prologue,
> *************** arm_get_next_pc (CORE_ADDR pc)
> *** 2050,2056 ****
> static void
> arm_software_single_step (enum target_signal sig, int insert_bpt)
> {
> ! static int next_pc; /* State between setting and unsetting. */
> static char break_mem[BREAKPOINT_MAX]; /* Temporary storage for mem@bpt */
>
> if (insert_bpt)
> --- 2048,2054 ----
> static void
> arm_software_single_step (enum target_signal sig, int insert_bpt)
> {
> ! static int next_pc; /* State between setting and unsetting. */
> static char break_mem[BREAKPOINT_MAX]; /* Temporary storage for mem@bpt */
>
> if (insert_bpt)