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9eae7c5264
* dwarf2loc.h (dwarf2_per_cu_data): Declare. * dwarf2read.c (dwarf_stack_op_name): No longer static. Return type is const. Add 'def' argument. Add missing operators, remove unhandled ones. (decode_locdesc): Update. (dwarf2_always_disassemble): New global. (show_dwarf2_always_disassemble): New function. (_initialize_dwarf2_read): Add always-disassemble. (dwarf2_per_cu_offset_size): New function. * dwarf2loc.c (dwarf2_always_disassemble): Declare. (piece_end_p): New function. (locexpr_describe_location_piece): Replace 'size' argument with 'end'. Use piece_end_p. Rewrite recognition of TLS. Recognize some constants. Remove errors. (disassemble_dwarf_expression): New function. (locexpr_describe_location_1): Use disassemble_dwarf_expression. Add 'offset_size' argument. (loclist_describe_location): Change output formatting. * dwarf2expr.h (dwarf_stack_op_name): Declare. gdb/doc * gdb.texinfo (Maintenance Commands): Document maint set dwarf2 always-disassemble.
1983 lines
54 KiB
C
1983 lines
54 KiB
C
/* DWARF 2 location expression support for GDB.
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Copyright (C) 2003, 2005, 2007, 2008, 2009, 2010
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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 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 "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 "block.h"
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#include "dwarf2.h"
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#include "dwarf2expr.h"
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#include "dwarf2loc.h"
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#include "dwarf2-frame.h"
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#include "gdb_string.h"
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#include "gdb_assert.h"
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extern int dwarf2_always_disassemble;
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static void
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dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
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const gdb_byte **start, size_t *length);
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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 const 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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const gdb_byte *loc_ptr, *buf_end;
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int length;
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struct objfile *objfile = dwarf2_per_cu_objfile (baton->per_cu);
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struct gdbarch *gdbarch = get_objfile_arch (objfile);
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
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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 (objfile->section_offsets,
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SECT_OFF_TEXT (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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if (buf_end - loc_ptr < 2 * addr_size)
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error (_("find_location_expression: Corrupted DWARF expression."));
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low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
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loc_ptr += addr_size;
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/* A base-address-selection entry. */
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if (low == base_mask)
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{
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base_address = dwarf2_read_address (gdbarch,
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loc_ptr, buf_end, addr_size);
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loc_ptr += addr_size;
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continue;
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}
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high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
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loc_ptr += addr_size;
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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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/* 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, byte_order);
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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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struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
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CORE_ADDR result;
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int regnum;
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regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
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result = address_from_register (builtin_type (gdbarch)->builtin_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, const 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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/* Use block_linkage_function, which returns a real (not inlined)
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function, instead of get_frame_function, which may return an
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inlined function. */
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framefunc = block_linkage_function (get_frame_block (debaton->frame, NULL));
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/* If we found a frame-relative symbol then it was certainly within
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some function associated with a frame. If we can't find the frame,
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something has gone wrong. */
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gdb_assert (framefunc != NULL);
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dwarf_expr_frame_base_1 (framefunc,
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get_frame_address_in_block (debaton->frame),
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start, length);
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}
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static void
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dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
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const gdb_byte **start, size_t *length)
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{
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if (SYMBOL_LOCATION_BATON (framefunc) == NULL)
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*start = NULL;
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else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs)
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{
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struct dwarf2_loclist_baton *symbaton;
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symbaton = SYMBOL_LOCATION_BATON (framefunc);
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*start = find_location_expression (symbaton, length, pc);
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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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if (symbaton != NULL)
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{
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*length = symbaton->size;
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*start = symbaton->data;
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}
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else
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*start = NULL;
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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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/* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
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the frame in BATON. */
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static CORE_ADDR
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dwarf_expr_frame_cfa (void *baton)
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{
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struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
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return dwarf2_frame_cfa (debaton->frame);
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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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struct piece_closure
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{
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/* Reference count. */
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int refc;
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/* The number of pieces used to describe this variable. */
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int n_pieces;
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/* The target address size, used only for DWARF_VALUE_STACK. */
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int addr_size;
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/* The pieces themselves. */
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struct dwarf_expr_piece *pieces;
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};
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/* Allocate a closure for a value formed from separately-described
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PIECES. */
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static struct piece_closure *
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allocate_piece_closure (int n_pieces, struct dwarf_expr_piece *pieces,
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int addr_size)
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{
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struct piece_closure *c = XZALLOC (struct piece_closure);
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c->refc = 1;
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c->n_pieces = n_pieces;
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c->addr_size = addr_size;
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c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece);
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memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
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return c;
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}
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/* The lowest-level function to extract bits from a byte buffer.
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SOURCE is the buffer. It is updated if we read to the end of a
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byte.
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SOURCE_OFFSET_BITS is the offset of the first bit to read. It is
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updated to reflect the number of bits actually read.
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NBITS is the number of bits we want to read. It is updated to
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reflect the number of bits actually read. This function may read
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fewer bits.
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BITS_BIG_ENDIAN is taken directly from gdbarch.
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This function returns the extracted bits. */
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static unsigned int
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extract_bits_primitive (const gdb_byte **source,
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unsigned int *source_offset_bits,
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int *nbits, int bits_big_endian)
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{
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unsigned int avail, mask, datum;
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gdb_assert (*source_offset_bits < 8);
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avail = 8 - *source_offset_bits;
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if (avail > *nbits)
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avail = *nbits;
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mask = (1 << avail) - 1;
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datum = **source;
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if (bits_big_endian)
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datum >>= 8 - (*source_offset_bits + *nbits);
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else
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datum >>= *source_offset_bits;
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datum &= mask;
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*nbits -= avail;
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*source_offset_bits += avail;
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if (*source_offset_bits >= 8)
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{
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*source_offset_bits -= 8;
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++*source;
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}
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return datum;
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}
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/* Extract some bits from a source buffer and move forward in the
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buffer.
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SOURCE is the source buffer. It is updated as bytes are read.
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SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as
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bits are read.
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NBITS is the number of bits to read.
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BITS_BIG_ENDIAN is taken directly from gdbarch.
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This function returns the bits that were read. */
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static unsigned int
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extract_bits (const gdb_byte **source, unsigned int *source_offset_bits,
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int nbits, int bits_big_endian)
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{
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unsigned int datum;
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gdb_assert (nbits > 0 && nbits <= 8);
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datum = extract_bits_primitive (source, source_offset_bits, &nbits,
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bits_big_endian);
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if (nbits > 0)
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{
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unsigned int more;
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more = extract_bits_primitive (source, source_offset_bits, &nbits,
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bits_big_endian);
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if (bits_big_endian)
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datum <<= nbits;
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else
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more <<= nbits;
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datum |= more;
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}
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return datum;
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}
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/* Write some bits into a buffer and move forward in the buffer.
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DATUM is the bits to write. The low-order bits of DATUM are used.
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DEST is the destination buffer. It is updated as bytes are
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written.
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DEST_OFFSET_BITS is the bit offset in DEST at which writing is
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done.
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NBITS is the number of valid bits in DATUM.
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BITS_BIG_ENDIAN is taken directly from gdbarch. */
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static void
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insert_bits (unsigned int datum,
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gdb_byte *dest, unsigned int dest_offset_bits,
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int nbits, int bits_big_endian)
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{
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unsigned int mask;
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gdb_assert (dest_offset_bits >= 0 && dest_offset_bits + nbits <= 8);
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mask = (1 << nbits) - 1;
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if (bits_big_endian)
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{
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datum <<= 8 - (dest_offset_bits + nbits);
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mask <<= 8 - (dest_offset_bits + nbits);
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}
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else
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{
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datum <<= dest_offset_bits;
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mask <<= dest_offset_bits;
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}
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gdb_assert ((datum & ~mask) == 0);
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*dest = (*dest & ~mask) | datum;
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}
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/* Copy bits from a source to a destination.
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DEST is where the bits should be written.
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DEST_OFFSET_BITS is the bit offset into DEST.
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SOURCE is the source of bits.
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SOURCE_OFFSET_BITS is the bit offset into SOURCE.
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BIT_COUNT is the number of bits to copy.
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BITS_BIG_ENDIAN is taken directly from gdbarch. */
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static void
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copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits,
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const gdb_byte *source, unsigned int source_offset_bits,
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unsigned int bit_count,
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int bits_big_endian)
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{
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unsigned int dest_avail;
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int datum;
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/* Reduce everything to byte-size pieces. */
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dest += dest_offset_bits / 8;
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dest_offset_bits %= 8;
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source += source_offset_bits / 8;
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source_offset_bits %= 8;
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dest_avail = 8 - dest_offset_bits % 8;
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/* See if we can fill the first destination byte. */
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if (dest_avail < bit_count)
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{
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datum = extract_bits (&source, &source_offset_bits, dest_avail,
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bits_big_endian);
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insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian);
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++dest;
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dest_offset_bits = 0;
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bit_count -= dest_avail;
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}
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/* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer
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than 8 bits remaining. */
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gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8);
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for (; bit_count >= 8; bit_count -= 8)
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{
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datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian);
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*dest++ = (gdb_byte) datum;
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}
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/* Finally, we may have a few leftover bits. */
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gdb_assert (bit_count <= 8 - dest_offset_bits % 8);
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if (bit_count > 0)
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{
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datum = extract_bits (&source, &source_offset_bits, bit_count,
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bits_big_endian);
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insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian);
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}
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}
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static void
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read_pieced_value (struct value *v)
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{
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int i;
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long offset = 0;
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ULONGEST bits_to_skip;
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gdb_byte *contents;
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struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
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struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
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size_t type_len;
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size_t buffer_size = 0;
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char *buffer = NULL;
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struct cleanup *cleanup;
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int bits_big_endian
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= gdbarch_bits_big_endian (get_type_arch (value_type (v)));
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if (value_type (v) != value_enclosing_type (v))
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internal_error (__FILE__, __LINE__,
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_("Should not be able to create a lazy value with "
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"an enclosing type"));
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cleanup = make_cleanup (free_current_contents, &buffer);
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contents = value_contents_raw (v);
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bits_to_skip = 8 * value_offset (v);
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type_len = 8 * TYPE_LENGTH (value_type (v));
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for (i = 0; i < c->n_pieces && offset < type_len; i++)
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{
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struct dwarf_expr_piece *p = &c->pieces[i];
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size_t this_size, this_size_bits;
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long dest_offset_bits, source_offset_bits, source_offset;
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const gdb_byte *intermediate_buffer;
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/* Compute size, source, and destination offsets for copying, in
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bits. */
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this_size_bits = p->size;
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if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
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{
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bits_to_skip -= this_size_bits;
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continue;
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}
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if (this_size_bits > type_len - offset)
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this_size_bits = type_len - offset;
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if (bits_to_skip > 0)
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{
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dest_offset_bits = 0;
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source_offset_bits = bits_to_skip;
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this_size_bits -= bits_to_skip;
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bits_to_skip = 0;
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}
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else
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{
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dest_offset_bits = offset;
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source_offset_bits = 0;
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}
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this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
|
||
source_offset = source_offset_bits / 8;
|
||
if (buffer_size < this_size)
|
||
{
|
||
buffer_size = this_size;
|
||
buffer = xrealloc (buffer, buffer_size);
|
||
}
|
||
intermediate_buffer = buffer;
|
||
|
||
/* Copy from the source to DEST_BUFFER. */
|
||
switch (p->location)
|
||
{
|
||
case DWARF_VALUE_REGISTER:
|
||
{
|
||
struct gdbarch *arch = get_frame_arch (frame);
|
||
int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch,
|
||
p->v.expr.value);
|
||
int reg_offset = source_offset;
|
||
|
||
if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
|
||
&& this_size < register_size (arch, gdb_regnum))
|
||
{
|
||
/* Big-endian, and we want less than full size. */
|
||
reg_offset = register_size (arch, gdb_regnum) - this_size;
|
||
/* We want the lower-order THIS_SIZE_BITS of the bytes
|
||
we extract from the register. */
|
||
source_offset_bits += 8 * this_size - this_size_bits;
|
||
}
|
||
|
||
if (gdb_regnum != -1)
|
||
{
|
||
get_frame_register_bytes (frame, gdb_regnum, reg_offset,
|
||
this_size, buffer);
|
||
}
|
||
else
|
||
{
|
||
error (_("Unable to access DWARF register number %s"),
|
||
paddress (arch, p->v.expr.value));
|
||
}
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_MEMORY:
|
||
if (p->v.expr.in_stack_memory)
|
||
read_stack (p->v.expr.value + source_offset, buffer, this_size);
|
||
else
|
||
read_memory (p->v.expr.value + source_offset, buffer, this_size);
|
||
break;
|
||
|
||
case DWARF_VALUE_STACK:
|
||
{
|
||
struct gdbarch *gdbarch = get_type_arch (value_type (v));
|
||
size_t n = this_size;
|
||
|
||
if (n > c->addr_size - source_offset)
|
||
n = (c->addr_size >= source_offset
|
||
? c->addr_size - source_offset
|
||
: 0);
|
||
if (n == 0)
|
||
{
|
||
/* Nothing. */
|
||
}
|
||
else if (source_offset == 0)
|
||
store_unsigned_integer (buffer, n,
|
||
gdbarch_byte_order (gdbarch),
|
||
p->v.expr.value);
|
||
else
|
||
{
|
||
gdb_byte bytes[sizeof (ULONGEST)];
|
||
|
||
store_unsigned_integer (bytes, n + source_offset,
|
||
gdbarch_byte_order (gdbarch),
|
||
p->v.expr.value);
|
||
memcpy (buffer, bytes + source_offset, n);
|
||
}
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_LITERAL:
|
||
{
|
||
size_t n = this_size;
|
||
|
||
if (n > p->v.literal.length - source_offset)
|
||
n = (p->v.literal.length >= source_offset
|
||
? p->v.literal.length - source_offset
|
||
: 0);
|
||
if (n != 0)
|
||
intermediate_buffer = p->v.literal.data + source_offset;
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_OPTIMIZED_OUT:
|
||
/* We just leave the bits empty for now. This is not ideal
|
||
but gdb currently does not have a nice way to represent
|
||
optimized-out pieces. */
|
||
warning (_("bits %ld-%ld in computed object were optimized out; "
|
||
"replacing with zeroes"),
|
||
offset,
|
||
offset + (long) this_size_bits);
|
||
break;
|
||
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("invalid location type"));
|
||
}
|
||
|
||
if (p->location != DWARF_VALUE_OPTIMIZED_OUT)
|
||
copy_bitwise (contents, dest_offset_bits,
|
||
intermediate_buffer, source_offset_bits % 8,
|
||
this_size_bits, bits_big_endian);
|
||
|
||
offset += this_size_bits;
|
||
}
|
||
|
||
do_cleanups (cleanup);
|
||
}
|
||
|
||
static void
|
||
write_pieced_value (struct value *to, struct value *from)
|
||
{
|
||
int i;
|
||
long offset = 0;
|
||
ULONGEST bits_to_skip;
|
||
const gdb_byte *contents;
|
||
struct piece_closure *c = (struct piece_closure *) value_computed_closure (to);
|
||
struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
|
||
size_t type_len;
|
||
size_t buffer_size = 0;
|
||
char *buffer = NULL;
|
||
struct cleanup *cleanup;
|
||
int bits_big_endian
|
||
= gdbarch_bits_big_endian (get_type_arch (value_type (to)));
|
||
|
||
if (frame == NULL)
|
||
{
|
||
set_value_optimized_out (to, 1);
|
||
return;
|
||
}
|
||
|
||
cleanup = make_cleanup (free_current_contents, &buffer);
|
||
|
||
contents = value_contents (from);
|
||
bits_to_skip = 8 * value_offset (to);
|
||
type_len = 8 * TYPE_LENGTH (value_type (to));
|
||
for (i = 0; i < c->n_pieces && offset < type_len; i++)
|
||
{
|
||
struct dwarf_expr_piece *p = &c->pieces[i];
|
||
size_t this_size_bits, this_size;
|
||
long dest_offset_bits, source_offset_bits, dest_offset, source_offset;
|
||
int need_bitwise;
|
||
const gdb_byte *source_buffer;
|
||
|
||
this_size_bits = p->size;
|
||
if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
|
||
{
|
||
bits_to_skip -= this_size_bits;
|
||
continue;
|
||
}
|
||
if (this_size_bits > type_len - offset)
|
||
this_size_bits = type_len - offset;
|
||
if (bits_to_skip > 0)
|
||
{
|
||
dest_offset_bits = bits_to_skip;
|
||
source_offset_bits = 0;
|
||
this_size_bits -= bits_to_skip;
|
||
bits_to_skip = 0;
|
||
}
|
||
else
|
||
{
|
||
dest_offset_bits = 0;
|
||
source_offset_bits = offset;
|
||
}
|
||
|
||
this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8;
|
||
source_offset = source_offset_bits / 8;
|
||
dest_offset = dest_offset_bits / 8;
|
||
if (dest_offset_bits % 8 == 0 && source_offset_bits % 8 == 0)
|
||
{
|
||
source_buffer = contents + source_offset;
|
||
need_bitwise = 0;
|
||
}
|
||
else
|
||
{
|
||
if (buffer_size < this_size)
|
||
{
|
||
buffer_size = this_size;
|
||
buffer = xrealloc (buffer, buffer_size);
|
||
}
|
||
source_buffer = buffer;
|
||
need_bitwise = 1;
|
||
}
|
||
|
||
switch (p->location)
|
||
{
|
||
case DWARF_VALUE_REGISTER:
|
||
{
|
||
struct gdbarch *arch = get_frame_arch (frame);
|
||
int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.expr.value);
|
||
int reg_offset = dest_offset;
|
||
|
||
if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
|
||
&& this_size <= register_size (arch, gdb_regnum))
|
||
/* Big-endian, and we want less than full size. */
|
||
reg_offset = register_size (arch, gdb_regnum) - this_size;
|
||
|
||
if (gdb_regnum != -1)
|
||
{
|
||
if (need_bitwise)
|
||
{
|
||
get_frame_register_bytes (frame, gdb_regnum, reg_offset,
|
||
this_size, buffer);
|
||
copy_bitwise (buffer, dest_offset_bits,
|
||
contents, source_offset_bits,
|
||
this_size_bits,
|
||
bits_big_endian);
|
||
}
|
||
|
||
put_frame_register_bytes (frame, gdb_regnum, reg_offset,
|
||
this_size, source_buffer);
|
||
}
|
||
else
|
||
{
|
||
error (_("Unable to write to DWARF register number %s"),
|
||
paddress (arch, p->v.expr.value));
|
||
}
|
||
}
|
||
break;
|
||
case DWARF_VALUE_MEMORY:
|
||
if (need_bitwise)
|
||
{
|
||
/* Only the first and last bytes can possibly have any
|
||
bits reused. */
|
||
read_memory (p->v.expr.value + dest_offset, buffer, 1);
|
||
read_memory (p->v.expr.value + dest_offset + this_size - 1,
|
||
buffer + this_size - 1, 1);
|
||
copy_bitwise (buffer, dest_offset_bits,
|
||
contents, source_offset_bits,
|
||
this_size_bits,
|
||
bits_big_endian);
|
||
}
|
||
|
||
write_memory (p->v.expr.value + dest_offset,
|
||
source_buffer, this_size);
|
||
break;
|
||
default:
|
||
set_value_optimized_out (to, 1);
|
||
goto done;
|
||
}
|
||
offset += this_size_bits;
|
||
}
|
||
|
||
done:
|
||
do_cleanups (cleanup);
|
||
}
|
||
|
||
static void *
|
||
copy_pieced_value_closure (struct value *v)
|
||
{
|
||
struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
|
||
|
||
++c->refc;
|
||
return c;
|
||
}
|
||
|
||
static void
|
||
free_pieced_value_closure (struct value *v)
|
||
{
|
||
struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
|
||
|
||
--c->refc;
|
||
if (c->refc == 0)
|
||
{
|
||
xfree (c->pieces);
|
||
xfree (c);
|
||
}
|
||
}
|
||
|
||
/* Functions for accessing a variable described by DW_OP_piece. */
|
||
static struct lval_funcs pieced_value_funcs = {
|
||
read_pieced_value,
|
||
write_pieced_value,
|
||
copy_pieced_value_closure,
|
||
free_pieced_value_closure
|
||
};
|
||
|
||
/* Evaluate a location description, starting at DATA and with length
|
||
SIZE, to find the current location of variable of TYPE in the context
|
||
of FRAME. */
|
||
|
||
static struct value *
|
||
dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
|
||
const gdb_byte *data, unsigned short size,
|
||
struct dwarf2_per_cu_data *per_cu)
|
||
{
|
||
struct value *retval;
|
||
struct dwarf_expr_baton baton;
|
||
struct dwarf_expr_context *ctx;
|
||
struct cleanup *old_chain;
|
||
|
||
if (size == 0)
|
||
{
|
||
retval = allocate_value (type);
|
||
VALUE_LVAL (retval) = not_lval;
|
||
set_value_optimized_out (retval, 1);
|
||
return retval;
|
||
}
|
||
|
||
baton.frame = frame;
|
||
baton.objfile = dwarf2_per_cu_objfile (per_cu);
|
||
|
||
ctx = new_dwarf_expr_context ();
|
||
old_chain = make_cleanup_free_dwarf_expr_context (ctx);
|
||
|
||
ctx->gdbarch = get_objfile_arch (baton.objfile);
|
||
ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
|
||
ctx->baton = &baton;
|
||
ctx->read_reg = dwarf_expr_read_reg;
|
||
ctx->read_mem = dwarf_expr_read_mem;
|
||
ctx->get_frame_base = dwarf_expr_frame_base;
|
||
ctx->get_frame_cfa = dwarf_expr_frame_cfa;
|
||
ctx->get_tls_address = dwarf_expr_tls_address;
|
||
|
||
dwarf_expr_eval (ctx, data, size);
|
||
if (ctx->num_pieces > 0)
|
||
{
|
||
struct piece_closure *c;
|
||
struct frame_id frame_id = get_frame_id (frame);
|
||
|
||
c = allocate_piece_closure (ctx->num_pieces, ctx->pieces,
|
||
ctx->addr_size);
|
||
retval = allocate_computed_value (type, &pieced_value_funcs, c);
|
||
VALUE_FRAME_ID (retval) = frame_id;
|
||
}
|
||
else
|
||
{
|
||
switch (ctx->location)
|
||
{
|
||
case DWARF_VALUE_REGISTER:
|
||
{
|
||
struct gdbarch *arch = get_frame_arch (frame);
|
||
CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0);
|
||
int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
|
||
|
||
if (gdb_regnum != -1)
|
||
retval = value_from_register (type, gdb_regnum, frame);
|
||
else
|
||
error (_("Unable to access DWARF register number %s"),
|
||
paddress (arch, dwarf_regnum));
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_MEMORY:
|
||
{
|
||
CORE_ADDR address = dwarf_expr_fetch (ctx, 0);
|
||
int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
|
||
|
||
retval = allocate_value (type);
|
||
VALUE_LVAL (retval) = lval_memory;
|
||
set_value_lazy (retval, 1);
|
||
if (in_stack_memory)
|
||
set_value_stack (retval, 1);
|
||
set_value_address (retval, address);
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_STACK:
|
||
{
|
||
ULONGEST value = (ULONGEST) dwarf_expr_fetch (ctx, 0);
|
||
bfd_byte *contents;
|
||
size_t n = ctx->addr_size;
|
||
|
||
retval = allocate_value (type);
|
||
contents = value_contents_raw (retval);
|
||
if (n > TYPE_LENGTH (type))
|
||
n = TYPE_LENGTH (type);
|
||
store_unsigned_integer (contents, n,
|
||
gdbarch_byte_order (ctx->gdbarch),
|
||
value);
|
||
}
|
||
break;
|
||
|
||
case DWARF_VALUE_LITERAL:
|
||
{
|
||
bfd_byte *contents;
|
||
size_t n = ctx->len;
|
||
|
||
retval = allocate_value (type);
|
||
contents = value_contents_raw (retval);
|
||
if (n > TYPE_LENGTH (type))
|
||
n = TYPE_LENGTH (type);
|
||
memcpy (contents, ctx->data, n);
|
||
}
|
||
break;
|
||
|
||
/* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context --
|
||
it can only be encountered when making a piece. */
|
||
case DWARF_VALUE_OPTIMIZED_OUT:
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("invalid location type"));
|
||
}
|
||
}
|
||
|
||
set_value_initialized (retval, ctx->initialized);
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
return retval;
|
||
}
|
||
|
||
/* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
|
||
|
||
struct needs_frame_baton
|
||
{
|
||
int needs_frame;
|
||
};
|
||
|
||
/* Reads from registers do require a frame. */
|
||
static CORE_ADDR
|
||
needs_frame_read_reg (void *baton, int regnum)
|
||
{
|
||
struct needs_frame_baton *nf_baton = baton;
|
||
|
||
nf_baton->needs_frame = 1;
|
||
return 1;
|
||
}
|
||
|
||
/* Reads from memory do not require a frame. */
|
||
static void
|
||
needs_frame_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
|
||
{
|
||
memset (buf, 0, len);
|
||
}
|
||
|
||
/* Frame-relative accesses do require a frame. */
|
||
static void
|
||
needs_frame_frame_base (void *baton, const gdb_byte **start, size_t * length)
|
||
{
|
||
static gdb_byte lit0 = DW_OP_lit0;
|
||
struct needs_frame_baton *nf_baton = baton;
|
||
|
||
*start = &lit0;
|
||
*length = 1;
|
||
|
||
nf_baton->needs_frame = 1;
|
||
}
|
||
|
||
/* CFA accesses require a frame. */
|
||
|
||
static CORE_ADDR
|
||
needs_frame_frame_cfa (void *baton)
|
||
{
|
||
struct needs_frame_baton *nf_baton = baton;
|
||
|
||
nf_baton->needs_frame = 1;
|
||
return 1;
|
||
}
|
||
|
||
/* Thread-local accesses do require a frame. */
|
||
static CORE_ADDR
|
||
needs_frame_tls_address (void *baton, CORE_ADDR offset)
|
||
{
|
||
struct needs_frame_baton *nf_baton = baton;
|
||
|
||
nf_baton->needs_frame = 1;
|
||
return 1;
|
||
}
|
||
|
||
/* Return non-zero iff the location expression at DATA (length SIZE)
|
||
requires a frame to evaluate. */
|
||
|
||
static int
|
||
dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
|
||
struct dwarf2_per_cu_data *per_cu)
|
||
{
|
||
struct needs_frame_baton baton;
|
||
struct dwarf_expr_context *ctx;
|
||
int in_reg;
|
||
struct cleanup *old_chain;
|
||
|
||
baton.needs_frame = 0;
|
||
|
||
ctx = new_dwarf_expr_context ();
|
||
old_chain = make_cleanup_free_dwarf_expr_context (ctx);
|
||
|
||
ctx->gdbarch = get_objfile_arch (dwarf2_per_cu_objfile (per_cu));
|
||
ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
|
||
ctx->baton = &baton;
|
||
ctx->read_reg = needs_frame_read_reg;
|
||
ctx->read_mem = needs_frame_read_mem;
|
||
ctx->get_frame_base = needs_frame_frame_base;
|
||
ctx->get_frame_cfa = needs_frame_frame_cfa;
|
||
ctx->get_tls_address = needs_frame_tls_address;
|
||
|
||
dwarf_expr_eval (ctx, data, size);
|
||
|
||
in_reg = ctx->location == DWARF_VALUE_REGISTER;
|
||
|
||
if (ctx->num_pieces > 0)
|
||
{
|
||
int i;
|
||
|
||
/* If the location has several pieces, and any of them are in
|
||
registers, then we will need a frame to fetch them from. */
|
||
for (i = 0; i < ctx->num_pieces; i++)
|
||
if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
|
||
in_reg = 1;
|
||
}
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
return baton.needs_frame || in_reg;
|
||
}
|
||
|
||
/* This struct keeps track of the pieces that make up a multi-location
|
||
object, for use in agent expression generation. It is
|
||
superficially similar to struct dwarf_expr_piece, but
|
||
dwarf_expr_piece is designed for use in immediate evaluation, and
|
||
does not, for example, have a way to record both base register and
|
||
offset. */
|
||
|
||
struct axs_var_loc
|
||
{
|
||
/* Memory vs register, etc */
|
||
enum axs_lvalue_kind kind;
|
||
|
||
/* If non-zero, number of bytes in this fragment */
|
||
unsigned bytes;
|
||
|
||
/* (GDB-numbered) reg, or base reg if >= 0 */
|
||
int reg;
|
||
|
||
/* offset from reg */
|
||
LONGEST offset;
|
||
};
|
||
|
||
static const gdb_byte *
|
||
dwarf2_tracepoint_var_loc (struct symbol *symbol,
|
||
struct agent_expr *ax,
|
||
struct axs_var_loc *loc,
|
||
struct gdbarch *gdbarch,
|
||
const gdb_byte *data, const gdb_byte *end)
|
||
{
|
||
if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
|
||
{
|
||
loc->kind = axs_lvalue_register;
|
||
loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0);
|
||
data += 1;
|
||
}
|
||
else if (data[0] == DW_OP_regx)
|
||
{
|
||
ULONGEST reg;
|
||
|
||
data = read_uleb128 (data + 1, end, ®);
|
||
loc->kind = axs_lvalue_register;
|
||
loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
|
||
}
|
||
else if (data[0] == DW_OP_fbreg)
|
||
{
|
||
struct block *b;
|
||
struct symbol *framefunc;
|
||
int frame_reg = 0;
|
||
LONGEST frame_offset;
|
||
const gdb_byte *base_data;
|
||
size_t base_size;
|
||
LONGEST base_offset = 0;
|
||
|
||
b = block_for_pc (ax->scope);
|
||
|
||
if (!b)
|
||
error (_("No block found for address"));
|
||
|
||
framefunc = block_linkage_function (b);
|
||
|
||
if (!framefunc)
|
||
error (_("No function found for block"));
|
||
|
||
dwarf_expr_frame_base_1 (framefunc, ax->scope,
|
||
&base_data, &base_size);
|
||
|
||
if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
|
||
{
|
||
const gdb_byte *buf_end;
|
||
|
||
frame_reg = base_data[0] - DW_OP_breg0;
|
||
buf_end = read_sleb128 (base_data + 1,
|
||
base_data + base_size, &base_offset);
|
||
if (buf_end != base_data + base_size)
|
||
error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."),
|
||
frame_reg, SYMBOL_PRINT_NAME (symbol));
|
||
}
|
||
else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
|
||
{
|
||
/* The frame base is just the register, with no offset. */
|
||
frame_reg = base_data[0] - DW_OP_reg0;
|
||
base_offset = 0;
|
||
}
|
||
else
|
||
{
|
||
/* We don't know what to do with the frame base expression,
|
||
so we can't trace this variable; give up. */
|
||
error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled, first opcode in base data is 0x%x."),
|
||
SYMBOL_PRINT_NAME (symbol), base_data[0]);
|
||
}
|
||
|
||
data = read_sleb128 (data + 1, end, &frame_offset);
|
||
|
||
loc->kind = axs_lvalue_memory;
|
||
loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg);
|
||
loc->offset = base_offset + frame_offset;
|
||
}
|
||
else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31)
|
||
{
|
||
unsigned int reg;
|
||
LONGEST offset;
|
||
|
||
reg = data[0] - DW_OP_breg0;
|
||
data = read_sleb128 (data + 1, end, &offset);
|
||
|
||
loc->kind = axs_lvalue_memory;
|
||
loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
|
||
loc->offset = offset;
|
||
}
|
||
else
|
||
error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."),
|
||
data[0], SYMBOL_PRINT_NAME (symbol));
|
||
|
||
return data;
|
||
}
|
||
|
||
/* Given the location of a piece, issue bytecodes that will access it. */
|
||
|
||
static void
|
||
dwarf2_tracepoint_var_access (struct agent_expr *ax,
|
||
struct axs_value *value,
|
||
struct axs_var_loc *loc)
|
||
{
|
||
value->kind = loc->kind;
|
||
|
||
switch (loc->kind)
|
||
{
|
||
case axs_lvalue_register:
|
||
value->u.reg = loc->reg;
|
||
break;
|
||
|
||
case axs_lvalue_memory:
|
||
ax_reg (ax, loc->reg);
|
||
if (loc->offset)
|
||
{
|
||
ax_const_l (ax, loc->offset);
|
||
ax_simple (ax, aop_add);
|
||
}
|
||
break;
|
||
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Unhandled value kind in dwarf2_tracepoint_var_access"));
|
||
}
|
||
}
|
||
|
||
static void
|
||
dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
|
||
struct agent_expr *ax, struct axs_value *value,
|
||
const gdb_byte *data, int size)
|
||
{
|
||
const gdb_byte *end = data + size;
|
||
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
||
/* In practice, a variable is not going to be spread across
|
||
dozens of registers or memory locations. If someone comes up
|
||
with a real-world example, revisit this. */
|
||
#define MAX_FRAGS 16
|
||
struct axs_var_loc fragments[MAX_FRAGS];
|
||
int nfrags = 0, frag;
|
||
int length = 0;
|
||
int piece_ok = 0;
|
||
int bad = 0;
|
||
int first = 1;
|
||
|
||
if (!data || size == 0)
|
||
{
|
||
value->optimized_out = 1;
|
||
return;
|
||
}
|
||
|
||
while (data < end)
|
||
{
|
||
if (!piece_ok)
|
||
{
|
||
if (nfrags == MAX_FRAGS)
|
||
error (_("Too many pieces in location for \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
fragments[nfrags].bytes = 0;
|
||
data = dwarf2_tracepoint_var_loc (symbol, ax, &fragments[nfrags],
|
||
gdbarch, data, end);
|
||
nfrags++;
|
||
piece_ok = 1;
|
||
}
|
||
else if (data[0] == DW_OP_piece)
|
||
{
|
||
ULONGEST bytes;
|
||
|
||
data = read_uleb128 (data + 1, end, &bytes);
|
||
/* Only deal with 4 byte fragments for now. */
|
||
if (bytes != 4)
|
||
error (_("DW_OP_piece %s not supported in location for \"%s\"."),
|
||
pulongest (bytes), SYMBOL_PRINT_NAME (symbol));
|
||
fragments[nfrags - 1].bytes = bytes;
|
||
length += bytes;
|
||
piece_ok = 0;
|
||
}
|
||
else
|
||
{
|
||
bad = 1;
|
||
break;
|
||
}
|
||
}
|
||
|
||
if (bad || data > end)
|
||
error (_("Corrupted DWARF expression for \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
/* If single expression, no pieces, convert to external format. */
|
||
if (length == 0)
|
||
{
|
||
dwarf2_tracepoint_var_access (ax, value, &fragments[0]);
|
||
return;
|
||
}
|
||
|
||
if (length != TYPE_LENGTH (value->type))
|
||
error (_("Inconsistent piece information for \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
/* Emit bytecodes to assemble the pieces into a single stack entry. */
|
||
|
||
for ((frag = (byte_order == BFD_ENDIAN_BIG ? 0 : nfrags - 1));
|
||
nfrags--;
|
||
(frag += (byte_order == BFD_ENDIAN_BIG ? 1 : -1)))
|
||
{
|
||
if (!first)
|
||
{
|
||
/* shift the previous fragment up 32 bits */
|
||
ax_const_l (ax, 32);
|
||
ax_simple (ax, aop_lsh);
|
||
}
|
||
|
||
dwarf2_tracepoint_var_access (ax, value, &fragments[frag]);
|
||
|
||
switch (value->kind)
|
||
{
|
||
case axs_lvalue_register:
|
||
ax_reg (ax, value->u.reg);
|
||
break;
|
||
|
||
case axs_lvalue_memory:
|
||
{
|
||
extern int trace_kludge; /* Ugh. */
|
||
|
||
gdb_assert (fragments[frag].bytes == 4);
|
||
if (trace_kludge)
|
||
ax_trace_quick (ax, 4);
|
||
ax_simple (ax, aop_ref32);
|
||
}
|
||
break;
|
||
}
|
||
|
||
if (!first)
|
||
{
|
||
/* or the new fragment into the previous */
|
||
ax_zero_ext (ax, 32);
|
||
ax_simple (ax, aop_bit_or);
|
||
}
|
||
first = 0;
|
||
}
|
||
value->kind = axs_rvalue;
|
||
}
|
||
|
||
|
||
/* Return the value of SYMBOL in FRAME using the DWARF-2 expression
|
||
evaluator to calculate the location. */
|
||
static struct value *
|
||
locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
|
||
{
|
||
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
struct value *val;
|
||
|
||
val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
|
||
dlbaton->size, dlbaton->per_cu);
|
||
|
||
return val;
|
||
}
|
||
|
||
/* Return non-zero iff we need a frame to evaluate SYMBOL. */
|
||
static int
|
||
locexpr_read_needs_frame (struct symbol *symbol)
|
||
{
|
||
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
|
||
return dwarf2_loc_desc_needs_frame (dlbaton->data, dlbaton->size,
|
||
dlbaton->per_cu);
|
||
}
|
||
|
||
/* Return true if DATA points to the end of a piece. END is one past
|
||
the last byte in the expression. */
|
||
|
||
static int
|
||
piece_end_p (const gdb_byte *data, const gdb_byte *end)
|
||
{
|
||
return data == end || data[0] == DW_OP_piece || data[0] == DW_OP_bit_piece;
|
||
}
|
||
|
||
/* Nicely describe a single piece of a location, returning an updated
|
||
position in the bytecode sequence. This function cannot recognize
|
||
all locations; if a location is not recognized, it simply returns
|
||
DATA. */
|
||
|
||
static const gdb_byte *
|
||
locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream,
|
||
CORE_ADDR addr, struct objfile *objfile,
|
||
const gdb_byte *data, const gdb_byte *end,
|
||
unsigned int addr_size)
|
||
{
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
int regno;
|
||
|
||
if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31)
|
||
{
|
||
regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0);
|
||
fprintf_filtered (stream, _("a variable in $%s"),
|
||
gdbarch_register_name (gdbarch, regno));
|
||
data += 1;
|
||
}
|
||
else if (data[0] == DW_OP_regx)
|
||
{
|
||
ULONGEST reg;
|
||
|
||
data = read_uleb128 (data + 1, end, ®);
|
||
regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
|
||
fprintf_filtered (stream, _("a variable in $%s"),
|
||
gdbarch_register_name (gdbarch, regno));
|
||
}
|
||
else if (data[0] == DW_OP_fbreg)
|
||
{
|
||
struct block *b;
|
||
struct symbol *framefunc;
|
||
int frame_reg = 0;
|
||
LONGEST frame_offset;
|
||
const gdb_byte *base_data, *new_data;
|
||
size_t base_size;
|
||
LONGEST base_offset = 0;
|
||
|
||
new_data = read_sleb128 (data + 1, end, &frame_offset);
|
||
if (!piece_end_p (new_data, end))
|
||
return data;
|
||
data = new_data;
|
||
|
||
b = block_for_pc (addr);
|
||
|
||
if (!b)
|
||
error (_("No block found for address for symbol \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
framefunc = block_linkage_function (b);
|
||
|
||
if (!framefunc)
|
||
error (_("No function found for block for symbol \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size);
|
||
|
||
if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31)
|
||
{
|
||
const gdb_byte *buf_end;
|
||
|
||
frame_reg = base_data[0] - DW_OP_breg0;
|
||
buf_end = read_sleb128 (base_data + 1,
|
||
base_data + base_size, &base_offset);
|
||
if (buf_end != base_data + base_size)
|
||
error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."),
|
||
frame_reg, SYMBOL_PRINT_NAME (symbol));
|
||
}
|
||
else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31)
|
||
{
|
||
/* The frame base is just the register, with no offset. */
|
||
frame_reg = base_data[0] - DW_OP_reg0;
|
||
base_offset = 0;
|
||
}
|
||
else
|
||
{
|
||
/* We don't know what to do with the frame base expression,
|
||
so we can't trace this variable; give up. */
|
||
error (_("Cannot describe location of symbol \"%s\"; "
|
||
"DWARF 2 encoding not handled, "
|
||
"first opcode in base data is 0x%x."),
|
||
SYMBOL_PRINT_NAME (symbol), base_data[0]);
|
||
}
|
||
|
||
regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg);
|
||
|
||
fprintf_filtered (stream, _("a variable at frame base reg $%s offset %s+%s"),
|
||
gdbarch_register_name (gdbarch, regno),
|
||
plongest (base_offset), plongest (frame_offset));
|
||
}
|
||
else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31
|
||
&& piece_end_p (data, end))
|
||
{
|
||
LONGEST offset;
|
||
|
||
regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0);
|
||
|
||
data = read_sleb128 (data + 1, end, &offset);
|
||
|
||
fprintf_filtered (stream,
|
||
_("a variable at offset %s from base reg $%s"),
|
||
plongest (offset),
|
||
gdbarch_register_name (gdbarch, regno));
|
||
}
|
||
|
||
/* The location expression for a TLS variable looks like this (on a
|
||
64-bit LE machine):
|
||
|
||
DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
|
||
(DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
|
||
|
||
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. */
|
||
|
||
else if (data + 1 + addr_size < end
|
||
&& data[0] == DW_OP_addr
|
||
&& data[1 + addr_size] == DW_OP_GNU_push_tls_address
|
||
&& piece_end_p (data + 2 + addr_size, end))
|
||
{
|
||
CORE_ADDR offset = dwarf2_read_address (gdbarch,
|
||
data + 1,
|
||
end,
|
||
addr_size);
|
||
|
||
fprintf_filtered (stream,
|
||
_("a thread-local variable at offset %s "
|
||
"in the thread-local storage for `%s'"),
|
||
paddress (gdbarch, offset), objfile->name);
|
||
|
||
data += 1 + addr_size + 1;
|
||
}
|
||
else if (data[0] >= DW_OP_lit0
|
||
&& data[0] <= DW_OP_lit31
|
||
&& data + 1 < end
|
||
&& data[1] == DW_OP_stack_value)
|
||
{
|
||
fprintf_filtered (stream, _("the constant %d"), data[0] - DW_OP_lit0);
|
||
data += 2;
|
||
}
|
||
|
||
return data;
|
||
}
|
||
|
||
/* Disassemble an expression, stopping at the end of a piece or at the
|
||
end of the expression. Returns a pointer to the next unread byte
|
||
in the input expression. If ALL is nonzero, then this function
|
||
will keep going until it reaches the end of the expression. */
|
||
|
||
static const gdb_byte *
|
||
disassemble_dwarf_expression (struct ui_file *stream,
|
||
struct gdbarch *arch, unsigned int addr_size,
|
||
int offset_size,
|
||
const gdb_byte *data, const gdb_byte *end,
|
||
int all)
|
||
{
|
||
const gdb_byte *start = data;
|
||
|
||
fprintf_filtered (stream, _("a complex DWARF expression:\n"));
|
||
|
||
while (data < end
|
||
&& (all
|
||
|| (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
|
||
{
|
||
enum dwarf_location_atom op = *data++;
|
||
CORE_ADDR addr;
|
||
ULONGEST ul;
|
||
LONGEST l;
|
||
const char *name;
|
||
|
||
name = dwarf_stack_op_name (op, 0);
|
||
|
||
if (!name)
|
||
error (_("Unrecognized DWARF opcode 0x%02x at %ld"),
|
||
op, (long) (data - start));
|
||
fprintf_filtered (stream, " % 4ld: %s", (long) (data - start), name);
|
||
|
||
switch (op)
|
||
{
|
||
case DW_OP_addr:
|
||
addr = dwarf2_read_address (arch, data, end, addr_size);
|
||
data += addr_size;
|
||
fprintf_filtered (stream, " %s", paddress (arch, addr));
|
||
break;
|
||
|
||
case DW_OP_const1u:
|
||
ul = extract_unsigned_integer (data, 1, gdbarch_byte_order (arch));
|
||
data += 1;
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
case DW_OP_const1s:
|
||
l = extract_signed_integer (data, 1, gdbarch_byte_order (arch));
|
||
data += 1;
|
||
fprintf_filtered (stream, " %s", plongest (l));
|
||
break;
|
||
case DW_OP_const2u:
|
||
ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
|
||
data += 2;
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
case DW_OP_const2s:
|
||
l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
|
||
data += 2;
|
||
fprintf_filtered (stream, " %s", plongest (l));
|
||
break;
|
||
case DW_OP_const4u:
|
||
ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
|
||
data += 4;
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
case DW_OP_const4s:
|
||
l = extract_signed_integer (data, 4, gdbarch_byte_order (arch));
|
||
data += 4;
|
||
fprintf_filtered (stream, " %s", plongest (l));
|
||
break;
|
||
case DW_OP_const8u:
|
||
ul = extract_unsigned_integer (data, 8, gdbarch_byte_order (arch));
|
||
data += 8;
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
case DW_OP_const8s:
|
||
l = extract_signed_integer (data, 8, gdbarch_byte_order (arch));
|
||
data += 8;
|
||
fprintf_filtered (stream, " %s", plongest (l));
|
||
break;
|
||
case DW_OP_constu:
|
||
data = read_uleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
case DW_OP_consts:
|
||
data = read_sleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s", plongest (l));
|
||
break;
|
||
|
||
case DW_OP_reg0:
|
||
case DW_OP_reg1:
|
||
case DW_OP_reg2:
|
||
case DW_OP_reg3:
|
||
case DW_OP_reg4:
|
||
case DW_OP_reg5:
|
||
case DW_OP_reg6:
|
||
case DW_OP_reg7:
|
||
case DW_OP_reg8:
|
||
case DW_OP_reg9:
|
||
case DW_OP_reg10:
|
||
case DW_OP_reg11:
|
||
case DW_OP_reg12:
|
||
case DW_OP_reg13:
|
||
case DW_OP_reg14:
|
||
case DW_OP_reg15:
|
||
case DW_OP_reg16:
|
||
case DW_OP_reg17:
|
||
case DW_OP_reg18:
|
||
case DW_OP_reg19:
|
||
case DW_OP_reg20:
|
||
case DW_OP_reg21:
|
||
case DW_OP_reg22:
|
||
case DW_OP_reg23:
|
||
case DW_OP_reg24:
|
||
case DW_OP_reg25:
|
||
case DW_OP_reg26:
|
||
case DW_OP_reg27:
|
||
case DW_OP_reg28:
|
||
case DW_OP_reg29:
|
||
case DW_OP_reg30:
|
||
case DW_OP_reg31:
|
||
fprintf_filtered (stream, " [$%s]",
|
||
gdbarch_register_name (arch, op - DW_OP_reg0));
|
||
break;
|
||
|
||
case DW_OP_regx:
|
||
data = read_uleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
|
||
gdbarch_register_name (arch, (int) ul));
|
||
break;
|
||
|
||
case DW_OP_implicit_value:
|
||
data = read_uleb128 (data, end, &ul);
|
||
data += ul;
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
|
||
case DW_OP_breg0:
|
||
case DW_OP_breg1:
|
||
case DW_OP_breg2:
|
||
case DW_OP_breg3:
|
||
case DW_OP_breg4:
|
||
case DW_OP_breg5:
|
||
case DW_OP_breg6:
|
||
case DW_OP_breg7:
|
||
case DW_OP_breg8:
|
||
case DW_OP_breg9:
|
||
case DW_OP_breg10:
|
||
case DW_OP_breg11:
|
||
case DW_OP_breg12:
|
||
case DW_OP_breg13:
|
||
case DW_OP_breg14:
|
||
case DW_OP_breg15:
|
||
case DW_OP_breg16:
|
||
case DW_OP_breg17:
|
||
case DW_OP_breg18:
|
||
case DW_OP_breg19:
|
||
case DW_OP_breg20:
|
||
case DW_OP_breg21:
|
||
case DW_OP_breg22:
|
||
case DW_OP_breg23:
|
||
case DW_OP_breg24:
|
||
case DW_OP_breg25:
|
||
case DW_OP_breg26:
|
||
case DW_OP_breg27:
|
||
case DW_OP_breg28:
|
||
case DW_OP_breg29:
|
||
case DW_OP_breg30:
|
||
case DW_OP_breg31:
|
||
data = read_sleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s [$%s]", pulongest (ul),
|
||
gdbarch_register_name (arch, op - DW_OP_breg0));
|
||
break;
|
||
|
||
case DW_OP_bregx:
|
||
{
|
||
ULONGEST offset;
|
||
|
||
data = read_uleb128 (data, end, &ul);
|
||
data = read_sleb128 (data, end, &offset);
|
||
fprintf_filtered (stream, " register %s [$%s] offset %s",
|
||
pulongest (ul),
|
||
gdbarch_register_name (arch, (int) ul),
|
||
pulongest (offset));
|
||
}
|
||
break;
|
||
|
||
case DW_OP_fbreg:
|
||
data = read_sleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
|
||
case DW_OP_xderef_size:
|
||
case DW_OP_deref_size:
|
||
case DW_OP_pick:
|
||
fprintf_filtered (stream, " %d", *data);
|
||
++data;
|
||
break;
|
||
|
||
case DW_OP_plus_uconst:
|
||
data = read_uleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s", pulongest (ul));
|
||
break;
|
||
|
||
case DW_OP_skip:
|
||
l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
|
||
data += 2;
|
||
fprintf_filtered (stream, " to %ld",
|
||
(long) (data + l - start));
|
||
break;
|
||
|
||
case DW_OP_bra:
|
||
l = extract_signed_integer (data, 2, gdbarch_byte_order (arch));
|
||
data += 2;
|
||
fprintf_filtered (stream, " %ld",
|
||
(long) (data + l - start));
|
||
break;
|
||
|
||
case DW_OP_call2:
|
||
ul = extract_unsigned_integer (data, 2, gdbarch_byte_order (arch));
|
||
data += 2;
|
||
fprintf_filtered (stream, " offset %s", phex_nz (ul, 2));
|
||
break;
|
||
|
||
case DW_OP_call4:
|
||
ul = extract_unsigned_integer (data, 4, gdbarch_byte_order (arch));
|
||
data += 4;
|
||
fprintf_filtered (stream, " offset %s", phex_nz (ul, 4));
|
||
break;
|
||
|
||
case DW_OP_call_ref:
|
||
ul = extract_unsigned_integer (data, offset_size,
|
||
gdbarch_byte_order (arch));
|
||
data += offset_size;
|
||
fprintf_filtered (stream, " offset %s", phex_nz (ul, offset_size));
|
||
break;
|
||
|
||
case DW_OP_piece:
|
||
data = read_uleb128 (data, end, &ul);
|
||
fprintf_filtered (stream, " %s (bytes)", pulongest (ul));
|
||
break;
|
||
|
||
case DW_OP_bit_piece:
|
||
{
|
||
ULONGEST offset;
|
||
|
||
data = read_uleb128 (data, end, &ul);
|
||
data = read_uleb128 (data, end, &offset);
|
||
fprintf_filtered (stream, " size %s offset %s (bits)",
|
||
pulongest (ul), pulongest (offset));
|
||
}
|
||
break;
|
||
}
|
||
|
||
fprintf_filtered (stream, "\n");
|
||
}
|
||
|
||
return data;
|
||
}
|
||
|
||
/* Describe a single location, which may in turn consist of multiple
|
||
pieces. */
|
||
|
||
static void
|
||
locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr,
|
||
struct ui_file *stream,
|
||
const gdb_byte *data, int size,
|
||
struct objfile *objfile, unsigned int addr_size,
|
||
int offset_size)
|
||
{
|
||
const gdb_byte *end = data + size;
|
||
int first_piece = 1, bad = 0;
|
||
|
||
while (data < end)
|
||
{
|
||
const gdb_byte *here = data;
|
||
int disassemble = 1;
|
||
|
||
if (first_piece)
|
||
first_piece = 0;
|
||
else
|
||
fprintf_filtered (stream, _(", and "));
|
||
|
||
if (!dwarf2_always_disassemble)
|
||
{
|
||
data = locexpr_describe_location_piece (symbol, stream, addr, objfile,
|
||
data, end, addr_size);
|
||
/* If we printed anything, or if we have an empty piece,
|
||
then don't disassemble. */
|
||
if (data != here
|
||
|| data[0] == DW_OP_piece
|
||
|| data[0] == DW_OP_bit_piece)
|
||
disassemble = 0;
|
||
}
|
||
if (disassemble)
|
||
data = disassemble_dwarf_expression (stream, get_objfile_arch (objfile),
|
||
addr_size, offset_size, data, end,
|
||
dwarf2_always_disassemble);
|
||
|
||
if (data < end)
|
||
{
|
||
int empty = data == here;
|
||
|
||
if (disassemble)
|
||
fprintf_filtered (stream, " ");
|
||
if (data[0] == DW_OP_piece)
|
||
{
|
||
ULONGEST bytes;
|
||
|
||
data = read_uleb128 (data + 1, end, &bytes);
|
||
|
||
if (empty)
|
||
fprintf_filtered (stream, _("an empty %s-byte piece"),
|
||
pulongest (bytes));
|
||
else
|
||
fprintf_filtered (stream, _(" [%s-byte piece]"),
|
||
pulongest (bytes));
|
||
}
|
||
else if (data[0] == DW_OP_bit_piece)
|
||
{
|
||
ULONGEST bits, offset;
|
||
|
||
data = read_uleb128 (data + 1, end, &bits);
|
||
data = read_uleb128 (data, end, &offset);
|
||
|
||
if (empty)
|
||
fprintf_filtered (stream,
|
||
_("an empty %s-bit piece"),
|
||
pulongest (bits));
|
||
else
|
||
fprintf_filtered (stream,
|
||
_(" [%s-bit piece, offset %s bits]"),
|
||
pulongest (bits), pulongest (offset));
|
||
}
|
||
else
|
||
{
|
||
bad = 1;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (bad || data > end)
|
||
error (_("Corrupted DWARF2 expression for \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
}
|
||
|
||
/* Print a natural-language description of SYMBOL to STREAM. This
|
||
version is for a symbol with a single location. */
|
||
|
||
static void
|
||
locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr,
|
||
struct ui_file *stream)
|
||
{
|
||
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
|
||
unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
|
||
int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
|
||
|
||
locexpr_describe_location_1 (symbol, addr, stream, dlbaton->data, dlbaton->size,
|
||
objfile, addr_size, offset_size);
|
||
}
|
||
|
||
/* Describe the location of SYMBOL as an agent value in VALUE, generating
|
||
any necessary bytecode in AX. */
|
||
|
||
static void
|
||
locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch,
|
||
struct agent_expr *ax, struct axs_value *value)
|
||
{
|
||
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
|
||
dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value,
|
||
dlbaton->data, dlbaton->size);
|
||
}
|
||
|
||
/* The set of location functions used with the DWARF-2 expression
|
||
evaluator. */
|
||
const struct symbol_computed_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;
|
||
const 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_TYPE (symbol), frame, data, size,
|
||
dlbaton->per_cu);
|
||
|
||
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. This
|
||
version applies when there is a list of different locations, each
|
||
with a specified address range. */
|
||
|
||
static void
|
||
loclist_describe_location (struct symbol *symbol, CORE_ADDR addr,
|
||
struct ui_file *stream)
|
||
{
|
||
struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
CORE_ADDR low, high;
|
||
const gdb_byte *loc_ptr, *buf_end;
|
||
int length, first = 1;
|
||
struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
||
unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
|
||
int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
|
||
CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
|
||
/* Adjust base_address for relocatable objects. */
|
||
CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets,
|
||
SECT_OFF_TEXT (objfile));
|
||
CORE_ADDR base_address = dlbaton->base_address + base_offset;
|
||
|
||
loc_ptr = dlbaton->data;
|
||
buf_end = dlbaton->data + dlbaton->size;
|
||
|
||
fprintf_filtered (stream, _("multi-location:\n"));
|
||
|
||
/* Iterate through locations until we run out. */
|
||
while (1)
|
||
{
|
||
if (buf_end - loc_ptr < 2 * addr_size)
|
||
error (_("Corrupted DWARF expression for symbol \"%s\"."),
|
||
SYMBOL_PRINT_NAME (symbol));
|
||
|
||
low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
|
||
loc_ptr += addr_size;
|
||
|
||
/* A base-address-selection entry. */
|
||
if (low == base_mask)
|
||
{
|
||
base_address = dwarf2_read_address (gdbarch,
|
||
loc_ptr, buf_end, addr_size);
|
||
fprintf_filtered (stream, _(" Base address %s"),
|
||
paddress (gdbarch, base_address));
|
||
loc_ptr += addr_size;
|
||
continue;
|
||
}
|
||
|
||
high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
|
||
loc_ptr += addr_size;
|
||
|
||
/* An end-of-list entry. */
|
||
if (low == 0 && high == 0)
|
||
break;
|
||
|
||
/* Otherwise, a location expression entry. */
|
||
low += base_address;
|
||
high += base_address;
|
||
|
||
length = extract_unsigned_integer (loc_ptr, 2, byte_order);
|
||
loc_ptr += 2;
|
||
|
||
/* (It would improve readability to print only the minimum
|
||
necessary digits of the second number of the range.) */
|
||
fprintf_filtered (stream, _(" Range %s-%s: "),
|
||
paddress (gdbarch, low), paddress (gdbarch, high));
|
||
|
||
/* Now describe this particular location. */
|
||
locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length,
|
||
objfile, addr_size, offset_size);
|
||
|
||
fprintf_filtered (stream, "\n");
|
||
|
||
loc_ptr += length;
|
||
}
|
||
}
|
||
|
||
/* 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 gdbarch *gdbarch,
|
||
struct agent_expr *ax, struct axs_value *value)
|
||
{
|
||
struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
|
||
const gdb_byte *data;
|
||
size_t size;
|
||
|
||
data = find_location_expression (dlbaton, &size, ax->scope);
|
||
|
||
dwarf2_tracepoint_var_ref (symbol, gdbarch, ax, value, data, size);
|
||
}
|
||
|
||
/* The set of location functions used with the DWARF-2 expression
|
||
evaluator and location lists. */
|
||
const struct symbol_computed_ops dwarf2_loclist_funcs = {
|
||
loclist_read_variable,
|
||
loclist_read_needs_frame,
|
||
loclist_describe_location,
|
||
loclist_tracepoint_var_ref
|
||
};
|