1618 lines
46 KiB
C
1618 lines
46 KiB
C
/* Target-machine dependent code for Nios II, for GDB.
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Copyright (C) 2012-2014 Free Software Foundation, Inc.
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Contributed by Peter Brookes (pbrookes@altera.com)
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and Andrew Draper (adraper@altera.com).
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Contributed by Mentor Graphics, 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 "trad-frame.h"
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#include "dwarf2-frame.h"
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#include "symtab.h"
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#include "inferior.h"
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#include "gdbtypes.h"
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#include "gdbcore.h"
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#include "gdbcmd.h"
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#include "osabi.h"
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#include "target.h"
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#include "dis-asm.h"
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#include "regcache.h"
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#include "value.h"
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#include "symfile.h"
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#include "arch-utils.h"
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#include "floatformat.h"
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#include "gdb_assert.h"
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#include "infcall.h"
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#include "regset.h"
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#include "target-descriptions.h"
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/* To get entry_point_address. */
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#include "objfiles.h"
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/* Nios II ISA specific encodings and macros. */
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#include "opcode/nios2.h"
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/* Nios II specific header. */
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#include "nios2-tdep.h"
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#include "features/nios2.c"
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/* Control debugging information emitted in this file. */
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static int nios2_debug = 0;
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/* The following structures are used in the cache for prologue
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analysis; see the reg_value and reg_saved tables in
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struct nios2_unwind_cache, respectively. */
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/* struct reg_value is used to record that a register has the same value
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as reg at the given offset from the start of a function. */
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struct reg_value
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{
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int reg;
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unsigned int offset;
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};
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/* struct reg_saved is used to record that a register value has been saved at
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basereg + addr, for basereg >= 0. If basereg < 0, that indicates
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that the register is not known to have been saved. Note that when
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basereg == NIOS2_Z_REGNUM (that is, r0, which holds value 0),
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addr is an absolute address. */
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struct reg_saved
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{
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int basereg;
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CORE_ADDR addr;
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};
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struct nios2_unwind_cache
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{
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/* The frame's base, optionally used by the high-level debug info. */
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CORE_ADDR base;
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/* The previous frame's inner most stack address. Used as this
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frame ID's stack_addr. */
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CORE_ADDR cfa;
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/* The address of the first instruction in this function. */
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CORE_ADDR pc;
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/* Which register holds the return address for the frame. */
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int return_regnum;
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/* Table indicating what changes have been made to each register. */
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struct reg_value reg_value[NIOS2_NUM_REGS];
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/* Table indicating where each register has been saved. */
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struct reg_saved reg_saved[NIOS2_NUM_REGS];
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};
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/* This array is a mapping from Dwarf-2 register numbering to GDB's. */
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static int nios2_dwarf2gdb_regno_map[] =
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{
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0, 1, 2, 3,
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4, 5, 6, 7,
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8, 9, 10, 11,
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12, 13, 14, 15,
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16, 17, 18, 19,
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20, 21, 22, 23,
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24, 25,
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NIOS2_GP_REGNUM, /* 26 */
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NIOS2_SP_REGNUM, /* 27 */
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NIOS2_FP_REGNUM, /* 28 */
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NIOS2_EA_REGNUM, /* 29 */
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NIOS2_BA_REGNUM, /* 30 */
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NIOS2_RA_REGNUM, /* 31 */
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NIOS2_PC_REGNUM, /* 32 */
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NIOS2_STATUS_REGNUM, /* 33 */
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NIOS2_ESTATUS_REGNUM, /* 34 */
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NIOS2_BSTATUS_REGNUM, /* 35 */
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NIOS2_IENABLE_REGNUM, /* 36 */
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NIOS2_IPENDING_REGNUM, /* 37 */
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NIOS2_CPUID_REGNUM, /* 38 */
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39, /* CTL6 */ /* 39 */
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NIOS2_EXCEPTION_REGNUM, /* 40 */
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NIOS2_PTEADDR_REGNUM, /* 41 */
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NIOS2_TLBACC_REGNUM, /* 42 */
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NIOS2_TLBMISC_REGNUM, /* 43 */
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NIOS2_ECCINJ_REGNUM, /* 44 */
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NIOS2_BADADDR_REGNUM, /* 45 */
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NIOS2_CONFIG_REGNUM, /* 46 */
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NIOS2_MPUBASE_REGNUM, /* 47 */
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NIOS2_MPUACC_REGNUM /* 48 */
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};
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/* Implement the dwarf2_reg_to_regnum gdbarch method. */
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static int
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nios2_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int dw_reg)
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{
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if (dw_reg < 0 || dw_reg > NIOS2_NUM_REGS)
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{
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warning (_("Dwarf-2 uses unmapped register #%d"), dw_reg);
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return dw_reg;
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}
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return nios2_dwarf2gdb_regno_map[dw_reg];
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}
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/* Canonical names for the 49 registers. */
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static const char *const nios2_reg_names[NIOS2_NUM_REGS] =
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{
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"zero", "at", "r2", "r3", "r4", "r5", "r6", "r7",
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"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
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"r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
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"et", "bt", "gp", "sp", "fp", "ea", "sstatus", "ra",
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"pc",
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"status", "estatus", "bstatus", "ienable",
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"ipending", "cpuid", "ctl6", "exception",
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"pteaddr", "tlbacc", "tlbmisc", "eccinj",
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"badaddr", "config", "mpubase", "mpuacc"
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};
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/* Implement the register_name gdbarch method. */
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static const char *
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nios2_register_name (struct gdbarch *gdbarch, int regno)
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{
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/* Use mnemonic aliases for GPRs. */
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if (regno >= 0 && regno < NIOS2_NUM_REGS)
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return nios2_reg_names[regno];
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else
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return tdesc_register_name (gdbarch, regno);
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}
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/* Implement the register_type gdbarch method. */
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static struct type *
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nios2_register_type (struct gdbarch *gdbarch, int regno)
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{
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/* If the XML description has register information, use that to
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determine the register type. */
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if (tdesc_has_registers (gdbarch_target_desc (gdbarch)))
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return tdesc_register_type (gdbarch, regno);
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if (regno == NIOS2_PC_REGNUM)
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return builtin_type (gdbarch)->builtin_func_ptr;
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else if (regno == NIOS2_SP_REGNUM)
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return builtin_type (gdbarch)->builtin_data_ptr;
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else
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return builtin_type (gdbarch)->builtin_uint32;
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}
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/* Given a return value in REGCACHE with a type VALTYPE,
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extract and copy its value into VALBUF. */
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static void
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nios2_extract_return_value (struct gdbarch *gdbarch, struct type *valtype,
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struct regcache *regcache, gdb_byte *valbuf)
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{
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int len = TYPE_LENGTH (valtype);
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/* Return values of up to 8 bytes are returned in $r2 $r3. */
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if (len <= register_size (gdbarch, NIOS2_R2_REGNUM))
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regcache_cooked_read (regcache, NIOS2_R2_REGNUM, valbuf);
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else
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{
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gdb_assert (len <= (register_size (gdbarch, NIOS2_R2_REGNUM)
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+ register_size (gdbarch, NIOS2_R3_REGNUM)));
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regcache_cooked_read (regcache, NIOS2_R2_REGNUM, valbuf);
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regcache_cooked_read (regcache, NIOS2_R3_REGNUM, valbuf + 4);
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}
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}
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/* Write into appropriate registers a function return value
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of type TYPE, given in virtual format. */
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static void
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nios2_store_return_value (struct gdbarch *gdbarch, struct type *valtype,
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struct regcache *regcache, const gdb_byte *valbuf)
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{
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int len = TYPE_LENGTH (valtype);
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/* Return values of up to 8 bytes are returned in $r2 $r3. */
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if (len <= register_size (gdbarch, NIOS2_R2_REGNUM))
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regcache_cooked_write (regcache, NIOS2_R2_REGNUM, valbuf);
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else
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{
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gdb_assert (len <= (register_size (gdbarch, NIOS2_R2_REGNUM)
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+ register_size (gdbarch, NIOS2_R3_REGNUM)));
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regcache_cooked_write (regcache, NIOS2_R2_REGNUM, valbuf);
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regcache_cooked_write (regcache, NIOS2_R3_REGNUM, valbuf + 4);
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}
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}
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/* Set up the default values of the registers. */
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static void
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nios2_setup_default (struct nios2_unwind_cache *cache)
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{
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int i;
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for (i = 0; i < NIOS2_NUM_REGS; i++)
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{
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/* All registers start off holding their previous values. */
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cache->reg_value[i].reg = i;
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cache->reg_value[i].offset = 0;
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/* All registers start off not saved. */
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cache->reg_saved[i].basereg = -1;
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cache->reg_saved[i].addr = 0;
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}
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}
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/* Initialize the unwind cache. */
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static void
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nios2_init_cache (struct nios2_unwind_cache *cache, CORE_ADDR pc)
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{
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cache->base = 0;
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cache->cfa = 0;
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cache->pc = pc;
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cache->return_regnum = NIOS2_RA_REGNUM;
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nios2_setup_default (cache);
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}
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/* Helper function to identify when we're in a function epilogue;
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that is, the part of the function from the point at which the
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stack adjustment is made, to the return or sibcall. On Nios II,
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we want to check that the CURRENT_PC is a return-type instruction
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and that the previous instruction is a stack adjustment.
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START_PC is the beginning of the function in question. */
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static int
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nios2_in_epilogue_p (struct gdbarch *gdbarch,
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CORE_ADDR current_pc,
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CORE_ADDR start_pc)
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{
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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/* There has to be a previous instruction in the function. */
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if (current_pc > start_pc)
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{
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/* Check whether the previous instruction was a stack
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adjustment. */
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unsigned int insn
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= read_memory_unsigned_integer (current_pc - NIOS2_OPCODE_SIZE,
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NIOS2_OPCODE_SIZE, byte_order);
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if ((insn & 0xffc0003c) == 0xdec00004 /* ADDI sp, sp, */
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|| (insn & 0xffc1ffff) == 0xdec1883a /* ADD sp, sp, */
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|| (insn & 0xffc0003f) == 0xdec00017) /* LDW sp, constant(sp) */
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{
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/* Then check if it's followed by a return or a tail
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call. */
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insn = read_memory_unsigned_integer (current_pc, NIOS2_OPCODE_SIZE,
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byte_order);
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if (insn == 0xf800283a /* RET */
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|| insn == 0xe800083a /* ERET */
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|| (insn & 0x07ffffff) == 0x0000683a /* JMP */
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|| (insn & 0xffc0003f) == 6) /* BR */
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return 1;
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}
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}
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return 0;
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}
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/* Implement the in_function_epilogue_p gdbarch method. */
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static int
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nios2_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
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{
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CORE_ADDR func_addr;
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if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
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return nios2_in_epilogue_p (gdbarch, pc, func_addr);
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return 0;
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}
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/* Define some instruction patterns supporting wildcard bits via a
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mask. */
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typedef struct
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{
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unsigned int insn;
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unsigned int mask;
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} wild_insn;
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static const wild_insn profiler_insn[] =
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{
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{ 0x0010e03a, 0x00000000 }, /* nextpc r8 */
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{ 0xf813883a, 0x00000000 }, /* mov r9,ra */
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{ 0x02800034, 0x003fffc0 }, /* movhi r10,257 */
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{ 0x52800004, 0x003fffc0 }, /* addi r10,r10,-31992 */
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{ 0x00000000, 0xffffffc0 }, /* call <mcount> */
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{ 0x483f883a, 0x00000000 } /* mov ra,r9 */
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};
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static const wild_insn irqentry_insn[] =
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{
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{ 0x0031307a, 0x00000000 }, /* rdctl et,estatus */
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{ 0xc600004c, 0x00000000 }, /* andi et,et,1 */
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{ 0xc0000026, 0x003fffc0 }, /* beq et,zero, <software_exception> */
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{ 0x0031313a, 0x00000000 }, /* rdctl et,ipending */
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{ 0xc0000026, 0x003fffc0 } /* beq et,zero, <software_exception> */
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};
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/* Attempt to match SEQUENCE, which is COUNT insns long, at START_PC. */
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static int
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nios2_match_sequence (struct gdbarch *gdbarch, CORE_ADDR start_pc,
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const wild_insn *sequence, int count)
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{
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CORE_ADDR pc = start_pc;
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int i;
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unsigned int insn;
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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for (i = 0 ; i < count ; i++)
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{
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insn = read_memory_unsigned_integer (pc, NIOS2_OPCODE_SIZE, byte_order);
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if ((insn & ~sequence[i].mask) != sequence[i].insn)
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return 0;
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pc += NIOS2_OPCODE_SIZE;
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}
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return 1;
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}
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/* Do prologue analysis, returning the PC of the first instruction
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after the function prologue. Assumes CACHE has already been
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initialized. THIS_FRAME can be null, in which case we are only
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interested in skipping the prologue. Otherwise CACHE is filled in
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from the frame information.
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The prologue will consist of the following parts:
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1) Optional profiling instrumentation. The old version uses six
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instructions. We step over this if there is an exact match.
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nextpc r8
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mov r9, ra
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movhi r10, %hiadj(.LP2)
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addi r10, r10, %lo(.LP2)
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call mcount
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mov ra, r9
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The new version uses two or three instructions (the last of
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these might get merged in with the STW which saves RA to the
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stack). We interpret these.
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mov r8, ra
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call mcount
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mov ra, r8
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2) Optional interrupt entry decision. Again, we step over
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this if there is an exact match.
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rdctl et,estatus
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andi et,et,1
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beq et,zero, <software_exception>
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rdctl et,ipending
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beq et,zero, <software_exception>
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3) A stack adjustment or stack which, which will be one of:
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addi sp, sp, -constant
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or:
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movi r8, constant
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sub sp, sp, r8
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or
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movhi r8, constant
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addi r8, r8, constant
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sub sp, sp, r8
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or
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movhi rx, %hiadj(newstack)
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addhi rx, rx, %lo(newstack)
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stw sp, constant(rx)
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mov sp, rx
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4) An optional stack check, which can take either of these forms:
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bgeu sp, rx, +8
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break 3
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or
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bltu sp, rx, .Lstack_overflow
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...
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.Lstack_overflow:
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break 3
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5) Saving any registers which need to be saved. These will
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normally just be stored onto the stack:
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stw rx, constant(sp)
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but in the large frame case will use r8 as an offset back
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to the cfa:
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add r8, r8, sp
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stw rx, -constant(r8)
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Saving control registers looks slightly different:
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rdctl rx, ctlN
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stw rx, constant(sp)
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6) An optional FP setup, either if the user has requested a
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frame pointer or if the function calls alloca.
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This is always:
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mov fp, sp
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The prologue instructions may be interleaved, and the register
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saves and FP setup can occur in either order.
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To cope with all this variability we decode all the instructions
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from the start of the prologue until we hit a branch, call or
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return. For each of the instructions mentioned in 3, 4 and 5 we
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handle the limited cases of stores to the stack and operations
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on constant values. */
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static CORE_ADDR
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nios2_analyze_prologue (struct gdbarch *gdbarch, const CORE_ADDR start_pc,
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const CORE_ADDR current_pc,
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struct nios2_unwind_cache *cache,
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struct frame_info *this_frame)
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{
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/* Maximum lines of prologue to check.
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Note that this number should not be too large, else we can
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potentially end up iterating through unmapped memory. */
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CORE_ADDR limit_pc = start_pc + 200;
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int regno;
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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/* Does the frame set up the FP register? */
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int base_reg = 0;
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struct reg_value *value = cache->reg_value;
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struct reg_value temp_value[NIOS2_NUM_REGS];
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int i;
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/* Save the starting PC so we can correct the pc after running
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through the prolog, using symbol info. */
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CORE_ADDR pc = start_pc;
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/* Is this an exception handler? */
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int exception_handler = 0;
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/* What was the original value of SP (or fake original value for
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|
functions which switch stacks? */
|
|
CORE_ADDR frame_high;
|
|
|
|
/* Is this the end of the prologue? */
|
|
int within_prologue = 1;
|
|
|
|
CORE_ADDR prologue_end;
|
|
|
|
/* Is this the innermost function? */
|
|
int innermost = (this_frame ? (frame_relative_level (this_frame) == 0) : 1);
|
|
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog,
|
|
"{ nios2_analyze_prologue start=%s, current=%s ",
|
|
paddress (gdbarch, start_pc),
|
|
paddress (gdbarch, current_pc));
|
|
|
|
/* Set up the default values of the registers. */
|
|
nios2_setup_default (cache);
|
|
|
|
/* If the first few instructions are the profile entry, then skip
|
|
over them. Newer versions of the compiler use more efficient
|
|
profiling code. */
|
|
if (nios2_match_sequence (gdbarch, pc, profiler_insn,
|
|
ARRAY_SIZE (profiler_insn)))
|
|
pc += ARRAY_SIZE (profiler_insn) * NIOS2_OPCODE_SIZE;
|
|
|
|
/* If the first few instructions are an interrupt entry, then skip
|
|
over them too. */
|
|
if (nios2_match_sequence (gdbarch, pc, irqentry_insn,
|
|
ARRAY_SIZE (irqentry_insn)))
|
|
{
|
|
pc += ARRAY_SIZE (irqentry_insn) * NIOS2_OPCODE_SIZE;
|
|
exception_handler = 1;
|
|
}
|
|
|
|
prologue_end = start_pc;
|
|
|
|
/* Find the prologue instructions. */
|
|
while (pc < limit_pc && within_prologue)
|
|
{
|
|
/* Present instruction. */
|
|
uint32_t insn;
|
|
|
|
int prologue_insn = 0;
|
|
|
|
if (pc == current_pc)
|
|
{
|
|
/* When we reach the current PC we must save the current
|
|
register state (for the backtrace) but keep analysing
|
|
because there might be more to find out (eg. is this an
|
|
exception handler). */
|
|
memcpy (temp_value, value, sizeof (temp_value));
|
|
value = temp_value;
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog, "*");
|
|
}
|
|
|
|
insn = read_memory_unsigned_integer (pc, NIOS2_OPCODE_SIZE, byte_order);
|
|
pc += NIOS2_OPCODE_SIZE;
|
|
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog, "[%08X]", insn);
|
|
|
|
/* The following instructions can appear in the prologue. */
|
|
|
|
if ((insn & 0x0001ffff) == 0x0001883a)
|
|
{
|
|
/* ADD rc, ra, rb (also used for MOV) */
|
|
|
|
int ra = GET_IW_A (insn);
|
|
int rb = GET_IW_B (insn);
|
|
int rc = GET_IW_C (insn);
|
|
|
|
if (rc == NIOS2_SP_REGNUM
|
|
&& rb == 0
|
|
&& value[ra].reg == cache->reg_saved[NIOS2_SP_REGNUM].basereg)
|
|
{
|
|
/* If the previous value of SP is available somewhere
|
|
near the new stack pointer value then this is a
|
|
stack switch. */
|
|
|
|
/* If any registers were saved on the stack before then
|
|
we can't backtrace into them now. */
|
|
for (i = 0 ; i < NIOS2_NUM_REGS ; i++)
|
|
{
|
|
if (cache->reg_saved[i].basereg == NIOS2_SP_REGNUM)
|
|
cache->reg_saved[i].basereg = -1;
|
|
if (value[i].reg == NIOS2_SP_REGNUM)
|
|
value[i].reg = -1;
|
|
}
|
|
|
|
/* Create a fake "high water mark" 4 bytes above where SP
|
|
was stored and fake up the registers to be consistent
|
|
with that. */
|
|
value[NIOS2_SP_REGNUM].reg = NIOS2_SP_REGNUM;
|
|
value[NIOS2_SP_REGNUM].offset
|
|
= (value[ra].offset
|
|
- cache->reg_saved[NIOS2_SP_REGNUM].addr
|
|
- 4);
|
|
cache->reg_saved[NIOS2_SP_REGNUM].basereg = NIOS2_SP_REGNUM;
|
|
cache->reg_saved[NIOS2_SP_REGNUM].addr = -4;
|
|
}
|
|
|
|
else if (rc != 0)
|
|
{
|
|
if (value[rb].reg == 0)
|
|
value[rc].reg = value[ra].reg;
|
|
else if (value[ra].reg == 0)
|
|
value[rc].reg = value[rb].reg;
|
|
else
|
|
value[rc].reg = -1;
|
|
value[rc].offset = value[ra].offset + value[rb].offset;
|
|
}
|
|
prologue_insn = 1;
|
|
}
|
|
|
|
else if ((insn & 0x0001ffff) == 0x0001983a)
|
|
{
|
|
/* SUB rc, ra, rb */
|
|
|
|
int ra = GET_IW_A (insn);
|
|
int rb = GET_IW_B (insn);
|
|
int rc = GET_IW_C (insn);
|
|
|
|
if (rc != 0)
|
|
{
|
|
if (value[rb].reg == 0)
|
|
value[rc].reg = value[ra].reg;
|
|
else
|
|
value[rc].reg = -1;
|
|
value[rc].offset = value[ra].offset - value[rb].offset;
|
|
}
|
|
}
|
|
|
|
else if ((insn & 0x0000003f) == 0x00000004)
|
|
{
|
|
/* ADDI rb, ra, immed (also used for MOVI) */
|
|
short immed = GET_IW_IMM16 (insn);
|
|
int ra = GET_IW_A (insn);
|
|
int rb = GET_IW_B (insn);
|
|
|
|
/* The first stack adjustment is part of the prologue.
|
|
Any subsequent stack adjustments are either down to
|
|
alloca or the epilogue so stop analysing when we hit
|
|
them. */
|
|
if (rb == NIOS2_SP_REGNUM
|
|
&& (value[rb].offset != 0 || value[ra].reg != NIOS2_SP_REGNUM))
|
|
break;
|
|
|
|
if (rb != 0)
|
|
{
|
|
value[rb].reg = value[ra].reg;
|
|
value[rb].offset = value[ra].offset + immed;
|
|
}
|
|
|
|
prologue_insn = 1;
|
|
}
|
|
|
|
else if ((insn & 0x0000003f) == 0x00000034)
|
|
{
|
|
/* ORHI rb, ra, immed (also used for MOVHI) */
|
|
unsigned int immed = GET_IW_IMM16 (insn);
|
|
int ra = GET_IW_A (insn);
|
|
int rb = GET_IW_B (insn);
|
|
|
|
if (rb != 0)
|
|
{
|
|
value[rb].reg = (value[ra].reg == 0) ? 0 : -1;
|
|
value[rb].offset = value[ra].offset | (immed << 16);
|
|
}
|
|
}
|
|
|
|
else if ((insn & IW_OP_MASK) == OP_STW
|
|
|| (insn & IW_OP_MASK) == OP_STWIO)
|
|
{
|
|
/* STW rb, immediate(ra) */
|
|
|
|
short immed16 = GET_IW_IMM16 (insn);
|
|
int ra = GET_IW_A (insn);
|
|
int rb = GET_IW_B (insn);
|
|
|
|
/* Are we storing the original value of a register?
|
|
For exception handlers the value of EA-4 (return
|
|
address from interrupts etc) is sometimes stored. */
|
|
int orig = value[rb].reg;
|
|
if (orig > 0
|
|
&& (value[rb].offset == 0
|
|
|| (orig == NIOS2_EA_REGNUM && value[rb].offset == -4)))
|
|
{
|
|
/* We are most interested in stores to the stack, but
|
|
also take note of stores to other places as they
|
|
might be useful later. */
|
|
if ((value[ra].reg == NIOS2_SP_REGNUM
|
|
&& cache->reg_saved[orig].basereg != NIOS2_SP_REGNUM)
|
|
|| cache->reg_saved[orig].basereg == -1)
|
|
{
|
|
if (pc < current_pc)
|
|
{
|
|
/* Save off callee saved registers. */
|
|
cache->reg_saved[orig].basereg = value[ra].reg;
|
|
cache->reg_saved[orig].addr
|
|
= value[ra].offset + GET_IW_IMM16 (insn);
|
|
}
|
|
|
|
prologue_insn = 1;
|
|
|
|
if (orig == NIOS2_EA_REGNUM || orig == NIOS2_ESTATUS_REGNUM)
|
|
exception_handler = 1;
|
|
}
|
|
}
|
|
else
|
|
/* Non-stack memory writes are not part of the
|
|
prologue. */
|
|
within_prologue = 0;
|
|
}
|
|
|
|
else if ((insn & 0xffc1f83f) == 0x0001303a)
|
|
{
|
|
/* RDCTL rC, ctlN */
|
|
int rc = GET_IW_C (insn);
|
|
int n = GET_IW_CONTROL_REGNUM (insn);
|
|
|
|
if (rc != 0)
|
|
{
|
|
value[rc].reg = NIOS2_STATUS_REGNUM + n;
|
|
value[rc].offset = 0;
|
|
}
|
|
|
|
prologue_insn = 1;
|
|
}
|
|
|
|
else if ((insn & 0x0000003f) == 0
|
|
&& value[8].reg == NIOS2_RA_REGNUM
|
|
&& value[8].offset == 0
|
|
&& value[NIOS2_SP_REGNUM].reg == NIOS2_SP_REGNUM
|
|
&& value[NIOS2_SP_REGNUM].offset == 0)
|
|
{
|
|
/* A CALL instruction. This is treated as a call to mcount
|
|
if ra has been stored into r8 beforehand and if it's
|
|
before the stack adjust.
|
|
Note mcount corrupts r2-r3, r9-r15 & ra. */
|
|
for (i = 2 ; i <= 3 ; i++)
|
|
value[i].reg = -1;
|
|
for (i = 9 ; i <= 15 ; i++)
|
|
value[i].reg = -1;
|
|
value[NIOS2_RA_REGNUM].reg = -1;
|
|
|
|
prologue_insn = 1;
|
|
}
|
|
|
|
else if ((insn & 0xf83fffff) == 0xd800012e)
|
|
{
|
|
/* BGEU sp, rx, +8
|
|
BREAK 3
|
|
This instruction sequence is used in stack checking;
|
|
we can ignore it. */
|
|
unsigned int next_insn
|
|
= read_memory_unsigned_integer (pc, NIOS2_OPCODE_SIZE, byte_order);
|
|
|
|
if (next_insn != 0x003da0fa)
|
|
within_prologue = 0;
|
|
else
|
|
pc += NIOS2_OPCODE_SIZE;
|
|
}
|
|
|
|
else if ((insn & 0xf800003f) == 0xd8000036)
|
|
{
|
|
/* BLTU sp, rx, .Lstackoverflow
|
|
If the location branched to holds a BREAK 3 instruction
|
|
then this is also stack overflow detection. We can
|
|
ignore it. */
|
|
CORE_ADDR target_pc = pc + ((insn & 0x3fffc0) >> 6);
|
|
unsigned int target_insn
|
|
= read_memory_unsigned_integer (target_pc, NIOS2_OPCODE_SIZE,
|
|
byte_order);
|
|
|
|
if (target_insn != 0x003da0fa)
|
|
within_prologue = 0;
|
|
}
|
|
|
|
/* Any other instructions are allowed to be moved up into the
|
|
prologue. If we reach a branch, call or return then the
|
|
prologue is considered over. We also consider a second stack
|
|
adjustment as terminating the prologue (see above). */
|
|
else
|
|
{
|
|
switch (GET_IW_OP (insn))
|
|
{
|
|
case OP_BEQ:
|
|
case OP_BGE:
|
|
case OP_BGEU:
|
|
case OP_BLT:
|
|
case OP_BLTU:
|
|
case OP_BNE:
|
|
case OP_BR:
|
|
case OP_CALL:
|
|
within_prologue = 0;
|
|
break;
|
|
case OP_OPX:
|
|
if (GET_IW_OPX (insn) == OPX_RET
|
|
|| GET_IW_OPX (insn) == OPX_ERET
|
|
|| GET_IW_OPX (insn) == OPX_BRET
|
|
|| GET_IW_OPX (insn) == OPX_CALLR
|
|
|| GET_IW_OPX (insn) == OPX_JMP)
|
|
within_prologue = 0;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (prologue_insn)
|
|
prologue_end = pc;
|
|
}
|
|
|
|
/* If THIS_FRAME is NULL, we are being called from skip_prologue
|
|
and are only interested in the PROLOGUE_END value, so just
|
|
return that now and skip over the cache updates, which depend
|
|
on having frame information. */
|
|
if (this_frame == NULL)
|
|
return prologue_end;
|
|
|
|
/* If we are in the function epilogue and have already popped
|
|
registers off the stack in preparation for returning, then we
|
|
want to go back to the original register values. */
|
|
if (innermost && nios2_in_epilogue_p (gdbarch, current_pc, start_pc))
|
|
nios2_setup_default (cache);
|
|
|
|
/* Exception handlers use a different return address register. */
|
|
if (exception_handler)
|
|
cache->return_regnum = NIOS2_EA_REGNUM;
|
|
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog, "\n-> retreg=%d, ", cache->return_regnum);
|
|
|
|
if (cache->reg_value[NIOS2_FP_REGNUM].reg == NIOS2_SP_REGNUM)
|
|
/* If the FP now holds an offset from the CFA then this is a
|
|
normal frame which uses the frame pointer. */
|
|
base_reg = NIOS2_FP_REGNUM;
|
|
else if (cache->reg_value[NIOS2_SP_REGNUM].reg == NIOS2_SP_REGNUM)
|
|
/* FP doesn't hold an offset from the CFA. If SP still holds an
|
|
offset from the CFA then we might be in a function which omits
|
|
the frame pointer, or we might be partway through the prologue.
|
|
In both cases we can find the CFA using SP. */
|
|
base_reg = NIOS2_SP_REGNUM;
|
|
else
|
|
{
|
|
/* Somehow the stack pointer has been corrupted.
|
|
We can't return. */
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog, "<can't reach cfa> }\n");
|
|
return 0;
|
|
}
|
|
|
|
if (cache->reg_value[base_reg].offset == 0
|
|
|| cache->reg_saved[NIOS2_RA_REGNUM].basereg != NIOS2_SP_REGNUM
|
|
|| cache->reg_saved[cache->return_regnum].basereg != NIOS2_SP_REGNUM)
|
|
{
|
|
/* If the frame didn't adjust the stack, didn't save RA or
|
|
didn't save EA in an exception handler then it must either
|
|
be a leaf function (doesn't call any other functions) or it
|
|
can't return. If it has called another function then it
|
|
can't be a leaf, so set base == 0 to indicate that we can't
|
|
backtrace past it. */
|
|
|
|
if (!innermost)
|
|
{
|
|
/* If it isn't the innermost function then it can't be a
|
|
leaf, unless it was interrupted. Check whether RA for
|
|
this frame is the same as PC. If so then it probably
|
|
wasn't interrupted. */
|
|
CORE_ADDR ra
|
|
= get_frame_register_unsigned (this_frame, NIOS2_RA_REGNUM);
|
|
|
|
if (ra == current_pc)
|
|
{
|
|
if (nios2_debug)
|
|
fprintf_unfiltered
|
|
(gdb_stdlog,
|
|
"<noreturn ADJUST %s, r31@r%d+?>, r%d@r%d+?> }\n",
|
|
paddress (gdbarch, cache->reg_value[base_reg].offset),
|
|
cache->reg_saved[NIOS2_RA_REGNUM].basereg,
|
|
cache->return_regnum,
|
|
cache->reg_saved[cache->return_regnum].basereg);
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Get the value of whichever register we are using for the
|
|
base. */
|
|
cache->base = get_frame_register_unsigned (this_frame, base_reg);
|
|
|
|
/* What was the value of SP at the start of this function (or just
|
|
after the stack switch). */
|
|
frame_high = cache->base - cache->reg_value[base_reg].offset;
|
|
|
|
/* Adjust all the saved registers such that they contain addresses
|
|
instead of offsets. */
|
|
for (i = 0; i < NIOS2_NUM_REGS; i++)
|
|
if (cache->reg_saved[i].basereg == NIOS2_SP_REGNUM)
|
|
{
|
|
cache->reg_saved[i].basereg = NIOS2_Z_REGNUM;
|
|
cache->reg_saved[i].addr += frame_high;
|
|
}
|
|
|
|
for (i = 0; i < NIOS2_NUM_REGS; i++)
|
|
if (cache->reg_saved[i].basereg == NIOS2_GP_REGNUM)
|
|
{
|
|
CORE_ADDR gp = get_frame_register_unsigned (this_frame,
|
|
NIOS2_GP_REGNUM);
|
|
|
|
for ( ; i < NIOS2_NUM_REGS; i++)
|
|
if (cache->reg_saved[i].basereg == NIOS2_GP_REGNUM)
|
|
{
|
|
cache->reg_saved[i].basereg = NIOS2_Z_REGNUM;
|
|
cache->reg_saved[i].addr += gp;
|
|
}
|
|
}
|
|
|
|
/* Work out what the value of SP was on the first instruction of
|
|
this function. If we didn't switch stacks then this can be
|
|
trivially computed from the base address. */
|
|
if (cache->reg_saved[NIOS2_SP_REGNUM].basereg == NIOS2_Z_REGNUM)
|
|
cache->cfa
|
|
= read_memory_unsigned_integer (cache->reg_saved[NIOS2_SP_REGNUM].addr,
|
|
4, byte_order);
|
|
else
|
|
cache->cfa = frame_high;
|
|
|
|
/* Exception handlers restore ESTATUS into STATUS. */
|
|
if (exception_handler)
|
|
{
|
|
cache->reg_saved[NIOS2_STATUS_REGNUM]
|
|
= cache->reg_saved[NIOS2_ESTATUS_REGNUM];
|
|
cache->reg_saved[NIOS2_ESTATUS_REGNUM].basereg = -1;
|
|
}
|
|
|
|
if (nios2_debug)
|
|
fprintf_unfiltered (gdb_stdlog, "cfa=%s }\n",
|
|
paddress (gdbarch, cache->cfa));
|
|
|
|
return prologue_end;
|
|
}
|
|
|
|
/* Implement the skip_prologue gdbarch hook. */
|
|
|
|
static CORE_ADDR
|
|
nios2_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
|
|
{
|
|
CORE_ADDR limit_pc;
|
|
CORE_ADDR func_addr;
|
|
|
|
struct nios2_unwind_cache cache;
|
|
|
|
/* See if we can determine the end of the prologue via the symbol
|
|
table. If so, then return either PC, or the PC after the
|
|
prologue, whichever is greater. */
|
|
if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL))
|
|
{
|
|
CORE_ADDR post_prologue_pc
|
|
= skip_prologue_using_sal (gdbarch, func_addr);
|
|
|
|
if (post_prologue_pc != 0)
|
|
return max (start_pc, post_prologue_pc);
|
|
}
|
|
|
|
/* Prologue analysis does the rest.... */
|
|
nios2_init_cache (&cache, start_pc);
|
|
return nios2_analyze_prologue (gdbarch, start_pc, start_pc, &cache, NULL);
|
|
}
|
|
|
|
/* Implement the breakpoint_from_pc gdbarch hook. */
|
|
|
|
static const gdb_byte*
|
|
nios2_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *bp_addr,
|
|
int *bp_size)
|
|
{
|
|
/* break encoding: 31->27 26->22 21->17 16->11 10->6 5->0 */
|
|
/* 00000 00000 0x1d 0x2d 11111 0x3a */
|
|
/* 00000 00000 11101 101101 11111 111010 */
|
|
/* In bytes: 00000000 00111011 01101111 11111010 */
|
|
/* 0x0 0x3b 0x6f 0xfa */
|
|
static const gdb_byte breakpoint_le[] = {0xfa, 0x6f, 0x3b, 0x0};
|
|
static const gdb_byte breakpoint_be[] = {0x0, 0x3b, 0x6f, 0xfa};
|
|
|
|
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
|
|
|
|
*bp_size = 4;
|
|
if (gdbarch_byte_order_for_code (gdbarch) == BFD_ENDIAN_BIG)
|
|
return breakpoint_be;
|
|
else
|
|
return breakpoint_le;
|
|
}
|
|
|
|
/* Implement the print_insn gdbarch method. */
|
|
|
|
static int
|
|
nios2_print_insn (bfd_vma memaddr, disassemble_info *info)
|
|
{
|
|
if (info->endian == BFD_ENDIAN_BIG)
|
|
return print_insn_big_nios2 (memaddr, info);
|
|
else
|
|
return print_insn_little_nios2 (memaddr, info);
|
|
}
|
|
|
|
|
|
/* Implement the frame_align gdbarch method. */
|
|
|
|
static CORE_ADDR
|
|
nios2_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
|
|
{
|
|
return align_down (addr, 4);
|
|
}
|
|
|
|
|
|
/* Implement the return_value gdbarch method. */
|
|
|
|
static enum return_value_convention
|
|
nios2_return_value (struct gdbarch *gdbarch, struct value *function,
|
|
struct type *type, struct regcache *regcache,
|
|
gdb_byte *readbuf, const gdb_byte *writebuf)
|
|
{
|
|
if (TYPE_LENGTH (type) > 8)
|
|
return RETURN_VALUE_STRUCT_CONVENTION;
|
|
|
|
if (readbuf)
|
|
nios2_extract_return_value (gdbarch, type, regcache, readbuf);
|
|
if (writebuf)
|
|
nios2_store_return_value (gdbarch, type, regcache, writebuf);
|
|
|
|
return RETURN_VALUE_REGISTER_CONVENTION;
|
|
}
|
|
|
|
/* Implement the dummy_id gdbarch method. */
|
|
|
|
static struct frame_id
|
|
nios2_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
|
|
{
|
|
return frame_id_build
|
|
(get_frame_register_unsigned (this_frame, NIOS2_SP_REGNUM),
|
|
get_frame_pc (this_frame));
|
|
}
|
|
|
|
/* Implement the push_dummy_call gdbarch method. */
|
|
|
|
static CORE_ADDR
|
|
nios2_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
|
|
struct regcache *regcache, CORE_ADDR bp_addr,
|
|
int nargs, struct value **args, CORE_ADDR sp,
|
|
int struct_return, CORE_ADDR struct_addr)
|
|
{
|
|
int argreg;
|
|
int float_argreg;
|
|
int argnum;
|
|
int len = 0;
|
|
int stack_offset = 0;
|
|
CORE_ADDR func_addr = find_function_addr (function, NULL);
|
|
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
|
|
|
/* Set the return address register to point to the entry point of
|
|
the program, where a breakpoint lies in wait. */
|
|
regcache_cooked_write_signed (regcache, NIOS2_RA_REGNUM, bp_addr);
|
|
|
|
/* Now make space on the stack for the args. */
|
|
for (argnum = 0; argnum < nargs; argnum++)
|
|
len += align_up (TYPE_LENGTH (value_type (args[argnum])), 4);
|
|
sp -= len;
|
|
|
|
/* Initialize the register pointer. */
|
|
argreg = NIOS2_FIRST_ARGREG;
|
|
|
|
/* The struct_return pointer occupies the first parameter-passing
|
|
register. */
|
|
if (struct_return)
|
|
regcache_cooked_write_unsigned (regcache, argreg++, struct_addr);
|
|
|
|
/* Now load as many as possible of the first arguments into
|
|
registers, and push the rest onto the stack. Loop through args
|
|
from first to last. */
|
|
for (argnum = 0; argnum < nargs; argnum++)
|
|
{
|
|
const gdb_byte *val;
|
|
gdb_byte valbuf[MAX_REGISTER_SIZE];
|
|
struct value *arg = args[argnum];
|
|
struct type *arg_type = check_typedef (value_type (arg));
|
|
int len = TYPE_LENGTH (arg_type);
|
|
enum type_code typecode = TYPE_CODE (arg_type);
|
|
|
|
val = value_contents (arg);
|
|
|
|
/* Copy the argument to general registers or the stack in
|
|
register-sized pieces. Large arguments are split between
|
|
registers and stack. */
|
|
while (len > 0)
|
|
{
|
|
int partial_len = (len < 4 ? len : 4);
|
|
|
|
if (argreg <= NIOS2_LAST_ARGREG)
|
|
{
|
|
/* The argument is being passed in a register. */
|
|
CORE_ADDR regval = extract_unsigned_integer (val, partial_len,
|
|
byte_order);
|
|
|
|
regcache_cooked_write_unsigned (regcache, argreg, regval);
|
|
argreg++;
|
|
}
|
|
else
|
|
{
|
|
/* The argument is being passed on the stack. */
|
|
CORE_ADDR addr = sp + stack_offset;
|
|
|
|
write_memory (addr, val, partial_len);
|
|
stack_offset += align_up (partial_len, 4);
|
|
}
|
|
|
|
len -= partial_len;
|
|
val += partial_len;
|
|
}
|
|
}
|
|
|
|
regcache_cooked_write_signed (regcache, NIOS2_SP_REGNUM, sp);
|
|
|
|
/* Return adjusted stack pointer. */
|
|
return sp;
|
|
}
|
|
|
|
/* Implement the unwind_pc gdbarch method. */
|
|
|
|
static CORE_ADDR
|
|
nios2_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
|
|
{
|
|
gdb_byte buf[4];
|
|
|
|
frame_unwind_register (next_frame, NIOS2_PC_REGNUM, buf);
|
|
return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr);
|
|
}
|
|
|
|
/* Implement the unwind_sp gdbarch method. */
|
|
|
|
static CORE_ADDR
|
|
nios2_unwind_sp (struct gdbarch *gdbarch, struct frame_info *this_frame)
|
|
{
|
|
return frame_unwind_register_unsigned (this_frame, NIOS2_SP_REGNUM);
|
|
}
|
|
|
|
/* Use prologue analysis to fill in the register cache
|
|
*THIS_PROLOGUE_CACHE for THIS_FRAME. This function initializes
|
|
*THIS_PROLOGUE_CACHE first. */
|
|
|
|
static struct nios2_unwind_cache *
|
|
nios2_frame_unwind_cache (struct frame_info *this_frame,
|
|
void **this_prologue_cache)
|
|
{
|
|
struct gdbarch *gdbarch = get_frame_arch (this_frame);
|
|
CORE_ADDR current_pc;
|
|
struct nios2_unwind_cache *cache;
|
|
int i;
|
|
|
|
if (*this_prologue_cache)
|
|
return *this_prologue_cache;
|
|
|
|
cache = FRAME_OBSTACK_ZALLOC (struct nios2_unwind_cache);
|
|
*this_prologue_cache = cache;
|
|
|
|
/* Zero all fields. */
|
|
nios2_init_cache (cache, get_frame_func (this_frame));
|
|
|
|
/* Prologue analysis does the rest... */
|
|
current_pc = get_frame_pc (this_frame);
|
|
if (cache->pc != 0)
|
|
nios2_analyze_prologue (gdbarch, cache->pc, current_pc, cache, this_frame);
|
|
|
|
return cache;
|
|
}
|
|
|
|
/* Implement the this_id function for the normal unwinder. */
|
|
|
|
static void
|
|
nios2_frame_this_id (struct frame_info *this_frame, void **this_cache,
|
|
struct frame_id *this_id)
|
|
{
|
|
struct nios2_unwind_cache *cache =
|
|
nios2_frame_unwind_cache (this_frame, this_cache);
|
|
|
|
/* This marks the outermost frame. */
|
|
if (cache->base == 0)
|
|
return;
|
|
|
|
*this_id = frame_id_build (cache->cfa, cache->pc);
|
|
}
|
|
|
|
/* Implement the prev_register function for the normal unwinder. */
|
|
|
|
static struct value *
|
|
nios2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
|
|
int regnum)
|
|
{
|
|
struct nios2_unwind_cache *cache =
|
|
nios2_frame_unwind_cache (this_frame, this_cache);
|
|
|
|
gdb_assert (regnum >= 0 && regnum < NIOS2_NUM_REGS);
|
|
|
|
/* The PC of the previous frame is stored in the RA register of
|
|
the current frame. Frob regnum so that we pull the value from
|
|
the correct place. */
|
|
if (regnum == NIOS2_PC_REGNUM)
|
|
regnum = cache->return_regnum;
|
|
|
|
if (regnum == NIOS2_SP_REGNUM && cache->cfa)
|
|
return frame_unwind_got_constant (this_frame, regnum, cache->cfa);
|
|
|
|
/* If we've worked out where a register is stored then load it from
|
|
there. */
|
|
if (cache->reg_saved[regnum].basereg == NIOS2_Z_REGNUM)
|
|
return frame_unwind_got_memory (this_frame, regnum,
|
|
cache->reg_saved[regnum].addr);
|
|
|
|
return frame_unwind_got_register (this_frame, regnum, regnum);
|
|
}
|
|
|
|
/* Implement the this_base, this_locals, and this_args hooks
|
|
for the normal unwinder. */
|
|
|
|
static CORE_ADDR
|
|
nios2_frame_base_address (struct frame_info *this_frame, void **this_cache)
|
|
{
|
|
struct nios2_unwind_cache *info
|
|
= nios2_frame_unwind_cache (this_frame, this_cache);
|
|
|
|
return info->base;
|
|
}
|
|
|
|
/* Data structures for the normal prologue-analysis-based
|
|
unwinder. */
|
|
|
|
static const struct frame_unwind nios2_frame_unwind =
|
|
{
|
|
NORMAL_FRAME,
|
|
default_frame_unwind_stop_reason,
|
|
nios2_frame_this_id,
|
|
nios2_frame_prev_register,
|
|
NULL,
|
|
default_frame_sniffer
|
|
};
|
|
|
|
static const struct frame_base nios2_frame_base =
|
|
{
|
|
&nios2_frame_unwind,
|
|
nios2_frame_base_address,
|
|
nios2_frame_base_address,
|
|
nios2_frame_base_address
|
|
};
|
|
|
|
/* Fill in the register cache *THIS_CACHE for THIS_FRAME for use
|
|
in the stub unwinder. */
|
|
|
|
static struct trad_frame_cache *
|
|
nios2_stub_frame_cache (struct frame_info *this_frame, void **this_cache)
|
|
{
|
|
CORE_ADDR pc;
|
|
CORE_ADDR start_addr;
|
|
CORE_ADDR stack_addr;
|
|
struct trad_frame_cache *this_trad_cache;
|
|
struct gdbarch *gdbarch = get_frame_arch (this_frame);
|
|
int num_regs = gdbarch_num_regs (gdbarch);
|
|
|
|
if (*this_cache != NULL)
|
|
return *this_cache;
|
|
this_trad_cache = trad_frame_cache_zalloc (this_frame);
|
|
*this_cache = this_trad_cache;
|
|
|
|
/* The return address is in the link register. */
|
|
trad_frame_set_reg_realreg (this_trad_cache,
|
|
gdbarch_pc_regnum (gdbarch),
|
|
NIOS2_RA_REGNUM);
|
|
|
|
/* Frame ID, since it's a frameless / stackless function, no stack
|
|
space is allocated and SP on entry is the current SP. */
|
|
pc = get_frame_pc (this_frame);
|
|
find_pc_partial_function (pc, NULL, &start_addr, NULL);
|
|
stack_addr = get_frame_register_unsigned (this_frame, NIOS2_SP_REGNUM);
|
|
trad_frame_set_id (this_trad_cache, frame_id_build (start_addr, stack_addr));
|
|
/* Assume that the frame's base is the same as the stack pointer. */
|
|
trad_frame_set_this_base (this_trad_cache, stack_addr);
|
|
|
|
return this_trad_cache;
|
|
}
|
|
|
|
/* Implement the this_id function for the stub unwinder. */
|
|
|
|
static void
|
|
nios2_stub_frame_this_id (struct frame_info *this_frame, void **this_cache,
|
|
struct frame_id *this_id)
|
|
{
|
|
struct trad_frame_cache *this_trad_cache
|
|
= nios2_stub_frame_cache (this_frame, this_cache);
|
|
|
|
trad_frame_get_id (this_trad_cache, this_id);
|
|
}
|
|
|
|
/* Implement the prev_register function for the stub unwinder. */
|
|
|
|
static struct value *
|
|
nios2_stub_frame_prev_register (struct frame_info *this_frame,
|
|
void **this_cache, int regnum)
|
|
{
|
|
struct trad_frame_cache *this_trad_cache
|
|
= nios2_stub_frame_cache (this_frame, this_cache);
|
|
|
|
return trad_frame_get_register (this_trad_cache, this_frame, regnum);
|
|
}
|
|
|
|
/* Implement the sniffer function for the stub unwinder.
|
|
This unwinder is used for cases where the normal
|
|
prologue-analysis-based unwinder can't work,
|
|
such as PLT stubs. */
|
|
|
|
static int
|
|
nios2_stub_frame_sniffer (const struct frame_unwind *self,
|
|
struct frame_info *this_frame, void **cache)
|
|
{
|
|
gdb_byte dummy[4];
|
|
struct obj_section *s;
|
|
CORE_ADDR pc = get_frame_address_in_block (this_frame);
|
|
|
|
/* Use the stub unwinder for unreadable code. */
|
|
if (target_read_memory (get_frame_pc (this_frame), dummy, 4) != 0)
|
|
return 1;
|
|
|
|
if (in_plt_section (pc))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Define the data structures for the stub unwinder. */
|
|
|
|
static const struct frame_unwind nios2_stub_frame_unwind =
|
|
{
|
|
NORMAL_FRAME,
|
|
default_frame_unwind_stop_reason,
|
|
nios2_stub_frame_this_id,
|
|
nios2_stub_frame_prev_register,
|
|
NULL,
|
|
nios2_stub_frame_sniffer
|
|
};
|
|
|
|
/* Helper function to read an instruction at PC. */
|
|
|
|
static unsigned long
|
|
nios2_fetch_instruction (struct gdbarch *gdbarch, CORE_ADDR pc)
|
|
{
|
|
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
|
|
|
return read_memory_unsigned_integer (pc, NIOS2_OPCODE_SIZE, byte_order);
|
|
}
|
|
|
|
/* Determine where to set a single step breakpoint while considering
|
|
branch prediction. */
|
|
|
|
static CORE_ADDR
|
|
nios2_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
|
|
{
|
|
struct gdbarch *gdbarch = get_frame_arch (frame);
|
|
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
|
unsigned long inst;
|
|
int op;
|
|
int imm16;
|
|
int ra;
|
|
int rb;
|
|
int ras;
|
|
int rbs;
|
|
unsigned int rau;
|
|
unsigned int rbu;
|
|
|
|
inst = nios2_fetch_instruction (gdbarch, pc);
|
|
pc += NIOS2_OPCODE_SIZE;
|
|
|
|
imm16 = (short) GET_IW_IMM16 (inst);
|
|
ra = GET_IW_A (inst);
|
|
rb = GET_IW_B (inst);
|
|
ras = get_frame_register_signed (frame, ra);
|
|
rbs = get_frame_register_signed (frame, rb);
|
|
rau = get_frame_register_unsigned (frame, ra);
|
|
rbu = get_frame_register_unsigned (frame, rb);
|
|
|
|
switch (GET_IW_OP (inst))
|
|
{
|
|
case OP_BEQ:
|
|
if (ras == rbs)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BGE:
|
|
if (ras >= rbs)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BGEU:
|
|
if (rau >= rbu)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BLT:
|
|
if (ras < rbs)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BLTU:
|
|
if (rau < rbu)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BNE:
|
|
if (ras != rbs)
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_BR:
|
|
pc += imm16;
|
|
break;
|
|
|
|
case OP_JMPI:
|
|
case OP_CALL:
|
|
pc = (pc & 0xf0000000) | (GET_IW_IMM26 (inst) << 2);
|
|
break;
|
|
|
|
case OP_OPX:
|
|
switch (GET_IW_OPX (inst))
|
|
{
|
|
case OPX_JMP:
|
|
case OPX_CALLR:
|
|
case OPX_RET:
|
|
pc = ras;
|
|
break;
|
|
|
|
case OPX_TRAP:
|
|
if (tdep->syscall_next_pc != NULL)
|
|
return tdep->syscall_next_pc (frame);
|
|
|
|
default:
|
|
break;
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return pc;
|
|
}
|
|
|
|
/* Implement the software_single_step gdbarch method. */
|
|
|
|
static int
|
|
nios2_software_single_step (struct frame_info *frame)
|
|
{
|
|
struct gdbarch *gdbarch = get_frame_arch (frame);
|
|
struct address_space *aspace = get_frame_address_space (frame);
|
|
CORE_ADDR next_pc = nios2_get_next_pc (frame, get_frame_pc (frame));
|
|
|
|
insert_single_step_breakpoint (gdbarch, aspace, next_pc);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Implement the get_longjump_target gdbarch method. */
|
|
|
|
static int
|
|
nios2_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
|
|
{
|
|
struct gdbarch *gdbarch = get_frame_arch (frame);
|
|
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
|
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
|
CORE_ADDR jb_addr = get_frame_register_unsigned (frame, NIOS2_R4_REGNUM);
|
|
gdb_byte buf[4];
|
|
|
|
if (target_read_memory (jb_addr + (tdep->jb_pc * 4), buf, 4))
|
|
return 0;
|
|
|
|
*pc = extract_unsigned_integer (buf, 4, byte_order);
|
|
return 1;
|
|
}
|
|
|
|
/* Initialize the Nios II gdbarch. */
|
|
|
|
static struct gdbarch *
|
|
nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
|
|
{
|
|
struct gdbarch *gdbarch;
|
|
struct gdbarch_tdep *tdep;
|
|
int register_bytes, i;
|
|
struct tdesc_arch_data *tdesc_data = NULL;
|
|
const struct target_desc *tdesc = info.target_desc;
|
|
|
|
if (!tdesc_has_registers (tdesc))
|
|
/* Pick a default target description. */
|
|
tdesc = tdesc_nios2;
|
|
|
|
/* Check any target description for validity. */
|
|
if (tdesc_has_registers (tdesc))
|
|
{
|
|
const struct tdesc_feature *feature;
|
|
int valid_p;
|
|
|
|
feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nios2.cpu");
|
|
if (feature == NULL)
|
|
return NULL;
|
|
|
|
tdesc_data = tdesc_data_alloc ();
|
|
|
|
valid_p = 1;
|
|
|
|
for (i = 0; i < NIOS2_NUM_REGS; i++)
|
|
valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
|
|
nios2_reg_names[i]);
|
|
|
|
if (!valid_p)
|
|
{
|
|
tdesc_data_cleanup (tdesc_data);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* Find a candidate among the list of pre-declared architectures. */
|
|
arches = gdbarch_list_lookup_by_info (arches, &info);
|
|
if (arches != NULL)
|
|
return arches->gdbarch;
|
|
|
|
/* None found, create a new architecture from the information
|
|
provided. */
|
|
tdep = xcalloc (1, sizeof (struct gdbarch_tdep));
|
|
gdbarch = gdbarch_alloc (&info, tdep);
|
|
|
|
/* longjmp support not enabled by default. */
|
|
tdep->jb_pc = -1;
|
|
|
|
/* Data type sizes. */
|
|
set_gdbarch_ptr_bit (gdbarch, 32);
|
|
set_gdbarch_addr_bit (gdbarch, 32);
|
|
set_gdbarch_short_bit (gdbarch, 16);
|
|
set_gdbarch_int_bit (gdbarch, 32);
|
|
set_gdbarch_long_bit (gdbarch, 32);
|
|
set_gdbarch_long_long_bit (gdbarch, 64);
|
|
set_gdbarch_float_bit (gdbarch, 32);
|
|
set_gdbarch_double_bit (gdbarch, 64);
|
|
|
|
set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
|
|
set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
|
|
|
|
/* The register set. */
|
|
set_gdbarch_num_regs (gdbarch, NIOS2_NUM_REGS);
|
|
set_gdbarch_sp_regnum (gdbarch, NIOS2_SP_REGNUM);
|
|
set_gdbarch_pc_regnum (gdbarch, NIOS2_PC_REGNUM); /* Pseudo register PC */
|
|
|
|
set_gdbarch_register_name (gdbarch, nios2_register_name);
|
|
set_gdbarch_register_type (gdbarch, nios2_register_type);
|
|
|
|
/* Provide register mappings for stabs and dwarf2. */
|
|
set_gdbarch_stab_reg_to_regnum (gdbarch, nios2_dwarf_reg_to_regnum);
|
|
set_gdbarch_dwarf2_reg_to_regnum (gdbarch, nios2_dwarf_reg_to_regnum);
|
|
|
|
set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
|
|
|
|
/* Call dummy code. */
|
|
set_gdbarch_frame_align (gdbarch, nios2_frame_align);
|
|
|
|
set_gdbarch_return_value (gdbarch, nios2_return_value);
|
|
|
|
set_gdbarch_skip_prologue (gdbarch, nios2_skip_prologue);
|
|
set_gdbarch_in_function_epilogue_p (gdbarch, nios2_in_function_epilogue_p);
|
|
set_gdbarch_breakpoint_from_pc (gdbarch, nios2_breakpoint_from_pc);
|
|
|
|
set_gdbarch_dummy_id (gdbarch, nios2_dummy_id);
|
|
set_gdbarch_unwind_pc (gdbarch, nios2_unwind_pc);
|
|
set_gdbarch_unwind_sp (gdbarch, nios2_unwind_sp);
|
|
|
|
/* The dwarf2 unwinder will normally produce the best results if
|
|
the debug information is available, so register it first. */
|
|
dwarf2_append_unwinders (gdbarch);
|
|
frame_unwind_append_unwinder (gdbarch, &nios2_stub_frame_unwind);
|
|
frame_unwind_append_unwinder (gdbarch, &nios2_frame_unwind);
|
|
|
|
/* Single stepping. */
|
|
set_gdbarch_software_single_step (gdbarch, nios2_software_single_step);
|
|
|
|
/* Hook in ABI-specific overrides, if they have been registered. */
|
|
gdbarch_init_osabi (info, gdbarch);
|
|
|
|
if (tdep->jb_pc >= 0)
|
|
set_gdbarch_get_longjmp_target (gdbarch, nios2_get_longjmp_target);
|
|
|
|
frame_base_set_default (gdbarch, &nios2_frame_base);
|
|
|
|
set_gdbarch_print_insn (gdbarch, nios2_print_insn);
|
|
|
|
/* Enable inferior call support. */
|
|
set_gdbarch_push_dummy_call (gdbarch, nios2_push_dummy_call);
|
|
|
|
if (tdesc_data)
|
|
tdesc_use_registers (gdbarch, tdesc, tdesc_data);
|
|
|
|
return gdbarch;
|
|
}
|
|
|
|
extern initialize_file_ftype _initialize_nios2_tdep; /* -Wmissing-prototypes */
|
|
|
|
void
|
|
_initialize_nios2_tdep (void)
|
|
{
|
|
gdbarch_register (bfd_arch_nios2, nios2_gdbarch_init, NULL);
|
|
initialize_tdesc_nios2 ();
|
|
|
|
/* Allow debugging this file's internals. */
|
|
add_setshow_boolean_cmd ("nios2", class_maintenance, &nios2_debug,
|
|
_("Set Nios II debugging."),
|
|
_("Show Nios II debugging."),
|
|
_("When on, Nios II specific debugging is enabled."),
|
|
NULL,
|
|
NULL,
|
|
&setdebuglist, &showdebuglist);
|
|
}
|