408 lines
12 KiB
C
408 lines
12 KiB
C
/* Target-dependent mdebug code for the ALPHA architecture.
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Copyright (C) 1993-2018 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "frame.h"
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#include "frame-unwind.h"
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#include "frame-base.h"
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#include "symtab.h"
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#include "gdbcore.h"
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#include "block.h"
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#include "trad-frame.h"
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#include "alpha-tdep.h"
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#include "mdebugread.h"
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/* FIXME: Some of this code should perhaps be merged with mips. */
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/* *INDENT-OFF* */
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/* Layout of a stack frame on the alpha:
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| |
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pdr members: | 7th ... nth arg, |
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| `pushed' by caller. |
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| |
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----------------|-------------------------------|<-- old_sp == vfp
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^ ^ ^ ^ | |
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| | | | | |
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| |localoff | Copies of 1st .. 6th |
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| | | | | argument if necessary. |
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| | | v | |
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| | | --- |-------------------------------|<-- LOCALS_ADDRESS
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| | | | |
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| | | | Locals and temporaries. |
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| | | | |
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| | | |-------------------------------|
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| | | | |
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|-fregoffset | Saved float registers. |
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| | | | F9 |
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| | | | . |
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| | | | . |
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| | | | F2 |
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| | v | |
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| | -------|-------------------------------|
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| | | |
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| | | Saved registers. |
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| | | S6 |
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|-regoffset | . |
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| | | . |
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| | | S0 |
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| | | pdr.pcreg |
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| v | |
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| ----------|-------------------------------|
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| | |
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frameoffset | Argument build area, gets |
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| | 7th ... nth arg for any |
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| | called procedure. |
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v | |
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-------------|-------------------------------|<-- sp
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| |
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*/
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/* *INDENT-ON* */
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#define PROC_LOW_ADDR(proc) ((proc)->pdr.adr)
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#define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
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#define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
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#define PROC_REG_MASK(proc) ((proc)->pdr.regmask)
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#define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask)
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#define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset)
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#define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset)
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#define PROC_PC_REG(proc) ((proc)->pdr.pcreg)
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#define PROC_LOCALOFF(proc) ((proc)->pdr.localoff)
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/* Locate the mdebug PDR for the given PC. Return null if one can't
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be found; you'll have to fall back to other methods in that case. */
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static struct mdebug_extra_func_info *
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find_proc_desc (CORE_ADDR pc)
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{
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const struct block *b = block_for_pc (pc);
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struct mdebug_extra_func_info *proc_desc = NULL;
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struct symbol *sym = NULL;
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const char *sh_name = NULL;
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if (b)
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{
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CORE_ADDR startaddr;
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find_pc_partial_function (pc, &sh_name, &startaddr, NULL);
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if (startaddr > BLOCK_START (b))
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/* This is the "pathological" case referred to in a comment in
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print_frame_info. It might be better to move this check into
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symbol reading. */
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sym = NULL;
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else
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sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN,
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0).symbol;
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}
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if (sym)
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{
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proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE_BYTES (sym);
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/* Correct incorrect setjmp procedure descriptor from the library
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to make backtrace through setjmp work. */
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if (proc_desc->pdr.pcreg == 0
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&& strcmp (sh_name, "setjmp") == 0)
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{
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proc_desc->pdr.pcreg = ALPHA_RA_REGNUM;
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proc_desc->pdr.regmask = 0x80000000;
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proc_desc->pdr.regoffset = -4;
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}
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/* If we never found a PDR for this function in symbol reading,
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then examine prologues to find the information. */
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if (proc_desc->pdr.framereg == -1)
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proc_desc = NULL;
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}
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return proc_desc;
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}
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/* Return a non-zero result if the function is frameless; zero otherwise. */
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static int
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alpha_mdebug_frameless (struct mdebug_extra_func_info *proc_desc)
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{
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return (PROC_FRAME_REG (proc_desc) == ALPHA_SP_REGNUM
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&& PROC_FRAME_OFFSET (proc_desc) == 0);
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}
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/* This returns the PC of the first inst after the prologue. If we can't
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find the prologue, then return 0. */
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static CORE_ADDR
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alpha_mdebug_after_prologue (CORE_ADDR pc,
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struct mdebug_extra_func_info *proc_desc)
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{
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if (proc_desc)
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{
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/* If function is frameless, then we need to do it the hard way. I
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strongly suspect that frameless always means prologueless... */
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if (alpha_mdebug_frameless (proc_desc))
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return 0;
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}
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return alpha_after_prologue (pc);
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}
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/* Return non-zero if we *might* be in a function prologue. Return zero
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if we are definitively *not* in a function prologue. */
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static int
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alpha_mdebug_in_prologue (CORE_ADDR pc,
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struct mdebug_extra_func_info *proc_desc)
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{
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CORE_ADDR after_prologue_pc = alpha_mdebug_after_prologue (pc, proc_desc);
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return (after_prologue_pc == 0 || pc < after_prologue_pc);
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}
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/* Frame unwinder that reads mdebug PDRs. */
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struct alpha_mdebug_unwind_cache
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{
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struct mdebug_extra_func_info *proc_desc;
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CORE_ADDR vfp;
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struct trad_frame_saved_reg *saved_regs;
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};
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/* Extract all of the information about the frame from PROC_DESC
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and store the resulting register save locations in the structure. */
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static struct alpha_mdebug_unwind_cache *
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alpha_mdebug_frame_unwind_cache (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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struct alpha_mdebug_unwind_cache *info;
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struct mdebug_extra_func_info *proc_desc;
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ULONGEST vfp;
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CORE_ADDR pc, reg_position;
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unsigned long mask;
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int ireg, returnreg;
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if (*this_prologue_cache)
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return (struct alpha_mdebug_unwind_cache *) *this_prologue_cache;
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info = FRAME_OBSTACK_ZALLOC (struct alpha_mdebug_unwind_cache);
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*this_prologue_cache = info;
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pc = get_frame_address_in_block (this_frame);
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/* ??? We don't seem to be able to cache the lookup of the PDR
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from alpha_mdebug_frame_p. It'd be nice if we could change
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the arguments to that function. Oh well. */
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proc_desc = find_proc_desc (pc);
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info->proc_desc = proc_desc;
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gdb_assert (proc_desc != NULL);
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info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
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/* The VFP of the frame is at FRAME_REG+FRAME_OFFSET. */
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vfp = get_frame_register_unsigned (this_frame, PROC_FRAME_REG (proc_desc));
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vfp += PROC_FRAME_OFFSET (info->proc_desc);
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info->vfp = vfp;
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/* Fill in the offsets for the registers which gen_mask says were saved. */
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reg_position = vfp + PROC_REG_OFFSET (proc_desc);
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mask = PROC_REG_MASK (proc_desc);
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returnreg = PROC_PC_REG (proc_desc);
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/* Note that RA is always saved first, regardless of its actual
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register number. */
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if (mask & (1 << returnreg))
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{
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/* Clear bit for RA so we don't save it again later. */
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mask &= ~(1 << returnreg);
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info->saved_regs[returnreg].addr = reg_position;
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reg_position += 8;
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}
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for (ireg = 0; ireg <= 31; ++ireg)
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if (mask & (1 << ireg))
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{
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info->saved_regs[ireg].addr = reg_position;
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reg_position += 8;
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}
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reg_position = vfp + PROC_FREG_OFFSET (proc_desc);
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mask = PROC_FREG_MASK (proc_desc);
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for (ireg = 0; ireg <= 31; ++ireg)
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if (mask & (1 << ireg))
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{
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info->saved_regs[ALPHA_FP0_REGNUM + ireg].addr = reg_position;
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reg_position += 8;
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}
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/* The stack pointer of the previous frame is computed by popping
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the current stack frame. */
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if (!trad_frame_addr_p (info->saved_regs, ALPHA_SP_REGNUM))
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trad_frame_set_value (info->saved_regs, ALPHA_SP_REGNUM, vfp);
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return info;
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}
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/* Given a GDB frame, determine the address of the calling function's
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frame. This will be used to create a new GDB frame struct. */
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static void
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alpha_mdebug_frame_this_id (struct frame_info *this_frame,
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void **this_prologue_cache,
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struct frame_id *this_id)
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{
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struct alpha_mdebug_unwind_cache *info
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= alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
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*this_id = frame_id_build (info->vfp, get_frame_func (this_frame));
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}
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/* Retrieve the value of REGNUM in FRAME. Don't give up! */
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static struct value *
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alpha_mdebug_frame_prev_register (struct frame_info *this_frame,
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void **this_prologue_cache, int regnum)
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{
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struct alpha_mdebug_unwind_cache *info
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= alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
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/* The PC of the previous frame is stored in the link register of
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the current frame. Frob regnum so that we pull the value from
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the correct place. */
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if (regnum == ALPHA_PC_REGNUM)
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regnum = PROC_PC_REG (info->proc_desc);
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return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
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}
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/* Return a non-zero result if the size of the stack frame exceeds the
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maximum debuggable frame size (512 Kbytes); zero otherwise. */
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static int
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alpha_mdebug_max_frame_size_exceeded (struct mdebug_extra_func_info *proc_desc)
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{
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/* If frame offset is null, we can be in two cases: either the
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function is frameless (the stack frame is null) or its
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frame exceeds the maximum debuggable frame size (512 Kbytes). */
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return (PROC_FRAME_OFFSET (proc_desc) == 0
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&& !alpha_mdebug_frameless (proc_desc));
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}
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static int
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alpha_mdebug_frame_sniffer (const struct frame_unwind *self,
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struct frame_info *this_frame,
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void **this_cache)
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{
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CORE_ADDR pc = get_frame_address_in_block (this_frame);
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struct mdebug_extra_func_info *proc_desc;
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/* If this PC does not map to a PDR, then clearly this isn't an
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mdebug frame. */
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proc_desc = find_proc_desc (pc);
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if (proc_desc == NULL)
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return 0;
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/* If we're in the prologue, the PDR for this frame is not yet valid.
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Say no here and we'll fall back on the heuristic unwinder. */
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if (alpha_mdebug_in_prologue (pc, proc_desc))
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return 0;
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/* If the maximum debuggable frame size has been exceeded, the
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proc desc is bogus. Fall back on the heuristic unwinder. */
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if (alpha_mdebug_max_frame_size_exceeded (proc_desc))
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return 0;
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return 1;
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}
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static const struct frame_unwind alpha_mdebug_frame_unwind = {
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NORMAL_FRAME,
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default_frame_unwind_stop_reason,
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alpha_mdebug_frame_this_id,
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alpha_mdebug_frame_prev_register,
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NULL,
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alpha_mdebug_frame_sniffer
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};
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static CORE_ADDR
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alpha_mdebug_frame_base_address (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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struct alpha_mdebug_unwind_cache *info
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= alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
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return info->vfp;
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}
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static CORE_ADDR
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alpha_mdebug_frame_locals_address (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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struct alpha_mdebug_unwind_cache *info
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= alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
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return info->vfp - PROC_LOCALOFF (info->proc_desc);
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}
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static CORE_ADDR
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alpha_mdebug_frame_args_address (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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struct alpha_mdebug_unwind_cache *info
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= alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
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return info->vfp - ALPHA_NUM_ARG_REGS * 8;
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}
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static const struct frame_base alpha_mdebug_frame_base = {
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&alpha_mdebug_frame_unwind,
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alpha_mdebug_frame_base_address,
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alpha_mdebug_frame_locals_address,
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alpha_mdebug_frame_args_address
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};
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static const struct frame_base *
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alpha_mdebug_frame_base_sniffer (struct frame_info *this_frame)
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{
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CORE_ADDR pc = get_frame_address_in_block (this_frame);
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struct mdebug_extra_func_info *proc_desc;
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/* If this PC does not map to a PDR, then clearly this isn't an
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mdebug frame. */
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proc_desc = find_proc_desc (pc);
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if (proc_desc == NULL)
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return NULL;
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/* If the maximum debuggable frame size has been exceeded, the
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proc desc is bogus. Fall back on the heuristic unwinder. */
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if (alpha_mdebug_max_frame_size_exceeded (proc_desc))
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return 0;
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return &alpha_mdebug_frame_base;
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}
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void
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alpha_mdebug_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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frame_unwind_append_unwinder (gdbarch, &alpha_mdebug_frame_unwind);
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frame_base_append_sniffer (gdbarch, alpha_mdebug_frame_base_sniffer);
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}
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