c9f4d5725d
* gdbarch.sh (REGISTER_NAME): Replace by gdbarch_register_name. * tracepoint.c (scope_info): Likewise. * target.c (debug_print_register): Likewise. * stack.c (frame_info): Likewise. * sh-tdep.c (sh_register_reggroup_p): Likewise. * sh64-tdep.c (sh64_do_fp_register, sh64_do_register) (sh64_media_print_registers_info) (sh64_compact_print_registers_info): Likewise. * rs6000-tdep.c (rs6000_register_reggroup_p): Likewise. * remote-sim.c (gdbsim_fetch_register): Likewise. * remote.c (packet_reg): Likewise (comment). * reggroups.c (default_register_reggroup_p): Likewise. * regcache.c (regcache_dump): Likewise. * printcmd.c (address_info): Likewise. * ppc-linux-nat.c (fetch_register, store_register): Likewise. * mt-dep.c (mt_registers_info): Likewise. * mn10300-tdep.c (mn10300_dwarf2_reg_to_regnum): Likewise (comment). * mips-tdep.c (mips_register_reggroup_p, mips_read_fp_register_single) (mips_read_fp_register_double, mips_print_fp_register) (mips_print_register, print_gp_register_row, mips_print_registers_info) (mips_register_sim_regno): Likewise. * m68klinux-nat.c (regmap, fetch_register, store_register): Likewise. * inf-ptrace.c (inf_ptrace_fetch_register) (inf_ptrace_store_register): Likewise. * infcmd.c (default_print_registers_info): Likewise. * ia64-linux-nat.c (ia64_linux_fetch_register) (ia64_linux_store_register): Likewise. * i386-linux-nat.c (fetch_register, store_register): Likewise. * i386gnu-nat.c (gnu_fetch_registers, gnu_store_registers): Likewise. * hppa-linux-nat.c (fetch_register, store_register): Likewise. * hppa-hpux-nat.c (hppa_hpux_fetch_register) (hppa_hpux_store_register): Likewise. * findvar.c (locate_var_value): Likewise. * dwarf2loc.c (locexpr_describe_location): Likewise. * dwarf2-frame.c (execute_cfa_program): Likewise. * arm-tdep.c (arm_push_dummy_call): Likewise. * arch-utils.c (legacy_register_sim_regno): Likewise. * alpha-tdep.c (alpha_register_reggroup_p): Likewise. * alpha-nat.c (fetch_osf_core_registers): Likewise. * mi/mi-main.c (mi_cmd_data_list_register_names) (mi_cmd_data_list_changed_registers, mi_cmd_data_list_register_values) (mi_cmd_data_write_register_values): Likewise. * gdbarch.c, gdbarch.h: Regenerate.
596 lines
17 KiB
C
596 lines
17 KiB
C
/* DWARF 2 location expression support for GDB.
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Copyright (C) 2003, 2005, 2007 Free Software Foundation, Inc.
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Contributed by Daniel Jacobowitz, MontaVista Software, 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 2 of the License, or (at
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your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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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, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "defs.h"
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#include "ui-out.h"
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#include "value.h"
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#include "frame.h"
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#include "gdbcore.h"
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#include "target.h"
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#include "inferior.h"
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#include "ax.h"
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#include "ax-gdb.h"
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#include "regcache.h"
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#include "objfiles.h"
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#include "exceptions.h"
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#include "elf/dwarf2.h"
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#include "dwarf2expr.h"
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#include "dwarf2loc.h"
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#include "gdb_string.h"
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#ifndef DWARF2_REG_TO_REGNUM
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#define DWARF2_REG_TO_REGNUM(REG) (REG)
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#endif
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/* A helper function for dealing with location lists. Given a
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symbol baton (BATON) and a pc value (PC), find the appropriate
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location expression, set *LOCEXPR_LENGTH, and return a pointer
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to the beginning of the expression. Returns NULL on failure.
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For now, only return the first matching location expression; there
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can be more than one in the list. */
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static gdb_byte *
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find_location_expression (struct dwarf2_loclist_baton *baton,
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size_t *locexpr_length, CORE_ADDR pc)
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{
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CORE_ADDR low, high;
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gdb_byte *loc_ptr, *buf_end;
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int length;
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unsigned int addr_size = TARGET_ADDR_BIT / TARGET_CHAR_BIT;
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CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
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/* Adjust base_address for relocatable objects. */
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CORE_ADDR base_offset = ANOFFSET (baton->objfile->section_offsets,
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SECT_OFF_TEXT (baton->objfile));
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CORE_ADDR base_address = baton->base_address + base_offset;
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loc_ptr = baton->data;
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buf_end = baton->data + baton->size;
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while (1)
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{
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low = dwarf2_read_address (loc_ptr, buf_end, &length);
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loc_ptr += length;
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high = dwarf2_read_address (loc_ptr, buf_end, &length);
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loc_ptr += length;
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/* An end-of-list entry. */
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if (low == 0 && high == 0)
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return NULL;
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/* A base-address-selection entry. */
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if ((low & base_mask) == base_mask)
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{
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base_address = high;
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continue;
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}
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/* Otherwise, a location expression entry. */
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low += base_address;
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high += base_address;
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length = extract_unsigned_integer (loc_ptr, 2);
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loc_ptr += 2;
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if (pc >= low && pc < high)
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{
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*locexpr_length = length;
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return loc_ptr;
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}
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loc_ptr += length;
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}
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}
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/* This is the baton used when performing dwarf2 expression
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evaluation. */
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struct dwarf_expr_baton
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{
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struct frame_info *frame;
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struct objfile *objfile;
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};
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/* Helper functions for dwarf2_evaluate_loc_desc. */
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/* Using the frame specified in BATON, return the value of register
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REGNUM, treated as a pointer. */
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static CORE_ADDR
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dwarf_expr_read_reg (void *baton, int dwarf_regnum)
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{
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struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
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CORE_ADDR result;
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int regnum;
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regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum);
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result = address_from_register (builtin_type_void_data_ptr,
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regnum, debaton->frame);
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return result;
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}
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/* Read memory at ADDR (length LEN) into BUF. */
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static void
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dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
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{
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read_memory (addr, buf, len);
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}
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/* Using the frame specified in BATON, find the location expression
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describing the frame base. Return a pointer to it in START and
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its length in LENGTH. */
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static void
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dwarf_expr_frame_base (void *baton, gdb_byte **start, size_t * length)
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{
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/* FIXME: cagney/2003-03-26: This code should be using
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get_frame_base_address(), and then implement a dwarf2 specific
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this_base method. */
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struct symbol *framefunc;
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struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
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framefunc = get_frame_function (debaton->frame);
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if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs)
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{
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struct dwarf2_loclist_baton *symbaton;
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struct frame_info *frame = debaton->frame;
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symbaton = SYMBOL_LOCATION_BATON (framefunc);
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*start = find_location_expression (symbaton, length,
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get_frame_address_in_block (frame));
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}
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else
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{
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struct dwarf2_locexpr_baton *symbaton;
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symbaton = SYMBOL_LOCATION_BATON (framefunc);
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*length = symbaton->size;
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*start = symbaton->data;
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}
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if (*start == NULL)
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error (_("Could not find the frame base for \"%s\"."),
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SYMBOL_NATURAL_NAME (framefunc));
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}
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/* Using the objfile specified in BATON, find the address for the
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current thread's thread-local storage with offset OFFSET. */
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static CORE_ADDR
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dwarf_expr_tls_address (void *baton, CORE_ADDR offset)
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{
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struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
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return target_translate_tls_address (debaton->objfile, offset);
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}
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/* Evaluate a location description, starting at DATA and with length
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SIZE, to find the current location of variable VAR in the context
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of FRAME. */
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static struct value *
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dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame,
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gdb_byte *data, unsigned short size,
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struct objfile *objfile)
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{
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struct gdbarch *arch = get_frame_arch (frame);
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struct value *retval;
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struct dwarf_expr_baton baton;
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struct dwarf_expr_context *ctx;
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if (size == 0)
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{
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retval = allocate_value (SYMBOL_TYPE (var));
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VALUE_LVAL (retval) = not_lval;
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set_value_optimized_out (retval, 1);
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return retval;
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}
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baton.frame = frame;
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baton.objfile = objfile;
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ctx = new_dwarf_expr_context ();
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ctx->baton = &baton;
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ctx->read_reg = dwarf_expr_read_reg;
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ctx->read_mem = dwarf_expr_read_mem;
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ctx->get_frame_base = dwarf_expr_frame_base;
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ctx->get_tls_address = dwarf_expr_tls_address;
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dwarf_expr_eval (ctx, data, size);
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if (ctx->num_pieces > 0)
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{
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int i;
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long offset = 0;
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bfd_byte *contents;
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retval = allocate_value (SYMBOL_TYPE (var));
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contents = value_contents_raw (retval);
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for (i = 0; i < ctx->num_pieces; i++)
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{
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struct dwarf_expr_piece *p = &ctx->pieces[i];
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if (p->in_reg)
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{
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bfd_byte regval[MAX_REGISTER_SIZE];
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int gdb_regnum = DWARF2_REG_TO_REGNUM (p->value);
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get_frame_register (frame, gdb_regnum, regval);
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memcpy (contents + offset, regval, p->size);
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}
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else /* In memory? */
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{
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read_memory (p->value, contents + offset, p->size);
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}
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offset += p->size;
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}
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}
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else if (ctx->in_reg)
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{
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CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0);
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int gdb_regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum);
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retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame);
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}
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else
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{
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CORE_ADDR address = dwarf_expr_fetch (ctx, 0);
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retval = allocate_value (SYMBOL_TYPE (var));
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VALUE_LVAL (retval) = lval_memory;
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set_value_lazy (retval, 1);
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VALUE_ADDRESS (retval) = address;
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}
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set_value_initialized (retval, ctx->initialized);
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free_dwarf_expr_context (ctx);
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return retval;
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}
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/* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
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struct needs_frame_baton
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{
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int needs_frame;
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};
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/* Reads from registers do require a frame. */
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static CORE_ADDR
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needs_frame_read_reg (void *baton, int regnum)
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{
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struct needs_frame_baton *nf_baton = baton;
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nf_baton->needs_frame = 1;
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return 1;
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}
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/* Reads from memory do not require a frame. */
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static void
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needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
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{
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memset (buf, 0, len);
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}
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/* Frame-relative accesses do require a frame. */
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static void
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needs_frame_frame_base (void *baton, gdb_byte **start, size_t * length)
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{
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static gdb_byte lit0 = DW_OP_lit0;
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struct needs_frame_baton *nf_baton = baton;
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*start = &lit0;
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*length = 1;
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nf_baton->needs_frame = 1;
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}
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/* Thread-local accesses do require a frame. */
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static CORE_ADDR
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needs_frame_tls_address (void *baton, CORE_ADDR offset)
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{
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struct needs_frame_baton *nf_baton = baton;
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nf_baton->needs_frame = 1;
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return 1;
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}
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/* Return non-zero iff the location expression at DATA (length SIZE)
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requires a frame to evaluate. */
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static int
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dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size)
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{
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struct needs_frame_baton baton;
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struct dwarf_expr_context *ctx;
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int in_reg;
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baton.needs_frame = 0;
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ctx = new_dwarf_expr_context ();
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ctx->baton = &baton;
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ctx->read_reg = needs_frame_read_reg;
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ctx->read_mem = needs_frame_read_mem;
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ctx->get_frame_base = needs_frame_frame_base;
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ctx->get_tls_address = needs_frame_tls_address;
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dwarf_expr_eval (ctx, data, size);
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in_reg = ctx->in_reg;
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if (ctx->num_pieces > 0)
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{
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int i;
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/* If the location has several pieces, and any of them are in
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registers, then we will need a frame to fetch them from. */
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for (i = 0; i < ctx->num_pieces; i++)
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if (ctx->pieces[i].in_reg)
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in_reg = 1;
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}
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free_dwarf_expr_context (ctx);
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return baton.needs_frame || in_reg;
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}
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static void
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dwarf2_tracepoint_var_ref (struct symbol *symbol, struct agent_expr *ax,
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struct axs_value *value, gdb_byte *data,
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int size)
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{
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if (size == 0)
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error (_("Symbol \"%s\" has been optimized out."),
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SYMBOL_PRINT_NAME (symbol));
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if (size == 1
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&& data[0] >= DW_OP_reg0
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&& data[0] <= DW_OP_reg31)
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{
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value->kind = axs_lvalue_register;
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value->u.reg = data[0] - DW_OP_reg0;
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}
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else if (data[0] == DW_OP_regx)
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{
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ULONGEST reg;
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read_uleb128 (data + 1, data + size, ®);
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value->kind = axs_lvalue_register;
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value->u.reg = reg;
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}
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else if (data[0] == DW_OP_fbreg)
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{
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/* And this is worse than just minimal; we should honor the frame base
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as above. */
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int frame_reg;
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LONGEST frame_offset;
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gdb_byte *buf_end;
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buf_end = read_sleb128 (data + 1, data + size, &frame_offset);
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if (buf_end != data + size)
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error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."),
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SYMBOL_PRINT_NAME (symbol));
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TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset);
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ax_reg (ax, frame_reg);
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ax_const_l (ax, frame_offset);
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ax_simple (ax, aop_add);
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value->kind = axs_lvalue_memory;
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}
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else if (data[0] >= DW_OP_breg0
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&& data[0] <= DW_OP_breg31)
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{
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unsigned int reg;
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LONGEST offset;
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gdb_byte *buf_end;
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reg = data[0] - DW_OP_breg0;
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buf_end = read_sleb128 (data + 1, data + size, &offset);
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if (buf_end != data + size)
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error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."),
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reg, SYMBOL_PRINT_NAME (symbol));
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ax_reg (ax, reg);
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ax_const_l (ax, offset);
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ax_simple (ax, aop_add);
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value->kind = axs_lvalue_memory;
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}
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else
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error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."),
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data[0], SYMBOL_PRINT_NAME (symbol));
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}
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/* Return the value of SYMBOL in FRAME using the DWARF-2 expression
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evaluator to calculate the location. */
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static struct value *
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locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
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{
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struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
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struct value *val;
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val = dwarf2_evaluate_loc_desc (symbol, frame, dlbaton->data, dlbaton->size,
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dlbaton->objfile);
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return val;
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}
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/* Return non-zero iff we need a frame to evaluate SYMBOL. */
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static int
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locexpr_read_needs_frame (struct symbol *symbol)
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{
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struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
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return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size);
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}
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/* Print a natural-language description of SYMBOL to STREAM. */
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static int
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locexpr_describe_location (struct symbol *symbol, struct ui_file *stream)
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{
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/* FIXME: be more extensive. */
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struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
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if (dlbaton->size == 1
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&& dlbaton->data[0] >= DW_OP_reg0
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&& dlbaton->data[0] <= DW_OP_reg31)
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{
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int regno = DWARF2_REG_TO_REGNUM (dlbaton->data[0] - DW_OP_reg0);
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fprintf_filtered (stream,
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"a variable in register %s",
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gdbarch_register_name (current_gdbarch, regno));
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return 1;
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}
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/* The location expression for a TLS variable looks like this (on a
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64-bit LE machine):
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DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
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(DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
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0x3 is the encoding for DW_OP_addr, which has an operand as long
|
||
as the size of an address on the target machine (here is 8
|
||
bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
|
||
The operand represents the offset at which the variable is within
|
||
the thread local storage. */
|
||
|
||
if (dlbaton->size > 1
|
||
&& dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address)
|
||
if (dlbaton->data[0] == DW_OP_addr)
|
||
{
|
||
int bytes_read;
|
||
CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1],
|
||
&dlbaton->data[dlbaton->size - 1],
|
||
&bytes_read);
|
||
fprintf_filtered (stream,
|
||
"a thread-local variable at offset %s in the "
|
||
"thread-local storage for `%s'",
|
||
paddr_nz (offset), dlbaton->objfile->name);
|
||
return 1;
|
||
}
|
||
|
||
|
||
fprintf_filtered (stream,
|
||
"a variable with complex or multiple locations (DWARF2)");
|
||
return 1;
|
||
}
|
||
|
||
|
||
/* Describe the location of SYMBOL as an agent value in VALUE, generating
|
||
any necessary bytecode in AX.
|
||
|
||
NOTE drow/2003-02-26: This function is extremely minimal, because
|
||
doing it correctly is extremely complicated and there is no
|
||
publicly available stub with tracepoint support for me to test
|
||
against. When there is one this function should be revisited. */
|
||
|
||
static void
|
||
locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax,
|
||
struct axs_value * value)
|
||
{
|
||
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
|
||
dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size);
|
||
}
|
||
|
||
/* The set of location functions used with the DWARF-2 expression
|
||
evaluator. */
|
||
const struct symbol_ops dwarf2_locexpr_funcs = {
|
||
locexpr_read_variable,
|
||
locexpr_read_needs_frame,
|
||
locexpr_describe_location,
|
||
locexpr_tracepoint_var_ref
|
||
};
|
||
|
||
|
||
/* Wrapper functions for location lists. These generally find
|
||
the appropriate location expression and call something above. */
|
||
|
||
/* Return the value of SYMBOL in FRAME using the DWARF-2 expression
|
||
evaluator to calculate the location. */
|
||
static struct value *
|
||
loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
|
||
{
|
||
struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
struct value *val;
|
||
gdb_byte *data;
|
||
size_t size;
|
||
|
||
data = find_location_expression (dlbaton, &size,
|
||
frame ? get_frame_address_in_block (frame)
|
||
: 0);
|
||
if (data == NULL)
|
||
{
|
||
val = allocate_value (SYMBOL_TYPE (symbol));
|
||
VALUE_LVAL (val) = not_lval;
|
||
set_value_optimized_out (val, 1);
|
||
}
|
||
else
|
||
val = dwarf2_evaluate_loc_desc (symbol, frame, data, size,
|
||
dlbaton->objfile);
|
||
|
||
return val;
|
||
}
|
||
|
||
/* Return non-zero iff we need a frame to evaluate SYMBOL. */
|
||
static int
|
||
loclist_read_needs_frame (struct symbol *symbol)
|
||
{
|
||
/* If there's a location list, then assume we need to have a frame
|
||
to choose the appropriate location expression. With tracking of
|
||
global variables this is not necessarily true, but such tracking
|
||
is disabled in GCC at the moment until we figure out how to
|
||
represent it. */
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Print a natural-language description of SYMBOL to STREAM. */
|
||
static int
|
||
loclist_describe_location (struct symbol *symbol, struct ui_file *stream)
|
||
{
|
||
/* FIXME: Could print the entire list of locations. */
|
||
fprintf_filtered (stream, "a variable with multiple locations");
|
||
return 1;
|
||
}
|
||
|
||
/* Describe the location of SYMBOL as an agent value in VALUE, generating
|
||
any necessary bytecode in AX. */
|
||
static void
|
||
loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax,
|
||
struct axs_value * value)
|
||
{
|
||
struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
gdb_byte *data;
|
||
size_t size;
|
||
|
||
data = find_location_expression (dlbaton, &size, ax->scope);
|
||
if (data == NULL)
|
||
error (_("Variable \"%s\" is not available."), SYMBOL_NATURAL_NAME (symbol));
|
||
|
||
dwarf2_tracepoint_var_ref (symbol, ax, value, data, size);
|
||
}
|
||
|
||
/* The set of location functions used with the DWARF-2 expression
|
||
evaluator and location lists. */
|
||
const struct symbol_ops dwarf2_loclist_funcs = {
|
||
loclist_read_variable,
|
||
loclist_read_needs_frame,
|
||
loclist_describe_location,
|
||
loclist_tracepoint_var_ref
|
||
};
|