| /* DWARF 2 location expression support for GDB. |
| |
| Copyright (C) 2003, 2005, 2007, 2008, 2009, 2010, 2011 |
| Free Software Foundation, Inc. |
| |
| Contributed by Daniel Jacobowitz, MontaVista Software, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "ui-out.h" |
| #include "value.h" |
| #include "frame.h" |
| #include "gdbcore.h" |
| #include "target.h" |
| #include "inferior.h" |
| #include "ax.h" |
| #include "ax-gdb.h" |
| #include "regcache.h" |
| #include "objfiles.h" |
| #include "exceptions.h" |
| #include "block.h" |
| |
| #include "dwarf2.h" |
| #include "dwarf2expr.h" |
| #include "dwarf2loc.h" |
| #include "dwarf2-frame.h" |
| |
| #include "gdb_string.h" |
| #include "gdb_assert.h" |
| |
| extern int dwarf2_always_disassemble; |
| |
| static void |
| dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc, |
| const gdb_byte **start, size_t *length); |
| |
| static struct value * |
| dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame, |
| const gdb_byte *data, unsigned short size, |
| struct dwarf2_per_cu_data *per_cu, |
| LONGEST byte_offset); |
| |
| /* A function for dealing with location lists. Given a |
| symbol baton (BATON) and a pc value (PC), find the appropriate |
| location expression, set *LOCEXPR_LENGTH, and return a pointer |
| to the beginning of the expression. Returns NULL on failure. |
| |
| For now, only return the first matching location expression; there |
| can be more than one in the list. */ |
| |
| const gdb_byte * |
| dwarf2_find_location_expression (struct dwarf2_loclist_baton *baton, |
| size_t *locexpr_length, CORE_ADDR pc) |
| { |
| CORE_ADDR low, high; |
| const gdb_byte *loc_ptr, *buf_end; |
| int length; |
| struct objfile *objfile = dwarf2_per_cu_objfile (baton->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 (baton->per_cu); |
| int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd); |
| CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
| /* Adjust base_address for relocatable objects. */ |
| CORE_ADDR base_offset = dwarf2_per_cu_text_offset (baton->per_cu); |
| CORE_ADDR base_address = baton->base_address + base_offset; |
| |
| loc_ptr = baton->data; |
| buf_end = baton->data + baton->size; |
| |
| while (1) |
| { |
| if (buf_end - loc_ptr < 2 * addr_size) |
| error (_("dwarf2_find_location_expression: " |
| "Corrupted DWARF expression.")); |
| |
| if (signed_addr_p) |
| low = extract_signed_integer (loc_ptr, addr_size, byte_order); |
| else |
| low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
| loc_ptr += addr_size; |
| |
| if (signed_addr_p) |
| high = extract_signed_integer (loc_ptr, addr_size, byte_order); |
| else |
| high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
| loc_ptr += addr_size; |
| |
| /* A base-address-selection entry. */ |
| if ((low & base_mask) == base_mask) |
| { |
| base_address = high + base_offset; |
| continue; |
| } |
| |
| /* An end-of-list entry. */ |
| if (low == 0 && high == 0) |
| return NULL; |
| |
| /* Otherwise, a location expression entry. */ |
| low += base_address; |
| high += base_address; |
| |
| length = extract_unsigned_integer (loc_ptr, 2, byte_order); |
| loc_ptr += 2; |
| |
| if (pc >= low && pc < high) |
| { |
| *locexpr_length = length; |
| return loc_ptr; |
| } |
| |
| loc_ptr += length; |
| } |
| } |
| |
| /* This is the baton used when performing dwarf2 expression |
| evaluation. */ |
| struct dwarf_expr_baton |
| { |
| struct frame_info *frame; |
| struct dwarf2_per_cu_data *per_cu; |
| }; |
| |
| /* Helper functions for dwarf2_evaluate_loc_desc. */ |
| |
| /* Using the frame specified in BATON, return the value of register |
| REGNUM, treated as a pointer. */ |
| static CORE_ADDR |
| dwarf_expr_read_reg (void *baton, int dwarf_regnum) |
| { |
| struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
| struct gdbarch *gdbarch = get_frame_arch (debaton->frame); |
| CORE_ADDR result; |
| int regnum; |
| |
| regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum); |
| result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr, |
| regnum, debaton->frame); |
| return result; |
| } |
| |
| /* Read memory at ADDR (length LEN) into BUF. */ |
| |
| static void |
| dwarf_expr_read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
| { |
| read_memory (addr, buf, len); |
| } |
| |
| /* Using the frame specified in BATON, find the location expression |
| describing the frame base. Return a pointer to it in START and |
| its length in LENGTH. */ |
| static void |
| dwarf_expr_frame_base (void *baton, const gdb_byte **start, size_t * length) |
| { |
| /* FIXME: cagney/2003-03-26: This code should be using |
| get_frame_base_address(), and then implement a dwarf2 specific |
| this_base method. */ |
| struct symbol *framefunc; |
| struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
| |
| /* Use block_linkage_function, which returns a real (not inlined) |
| function, instead of get_frame_function, which may return an |
| inlined function. */ |
| framefunc = block_linkage_function (get_frame_block (debaton->frame, NULL)); |
| |
| /* If we found a frame-relative symbol then it was certainly within |
| some function associated with a frame. If we can't find the frame, |
| something has gone wrong. */ |
| gdb_assert (framefunc != NULL); |
| |
| dwarf_expr_frame_base_1 (framefunc, |
| get_frame_address_in_block (debaton->frame), |
| start, length); |
| } |
| |
| static void |
| dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc, |
| const gdb_byte **start, size_t *length) |
| { |
| if (SYMBOL_LOCATION_BATON (framefunc) == NULL) |
| *start = NULL; |
| else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs) |
| { |
| struct dwarf2_loclist_baton *symbaton; |
| |
| symbaton = SYMBOL_LOCATION_BATON (framefunc); |
| *start = dwarf2_find_location_expression (symbaton, length, pc); |
| } |
| else |
| { |
| struct dwarf2_locexpr_baton *symbaton; |
| |
| symbaton = SYMBOL_LOCATION_BATON (framefunc); |
| if (symbaton != NULL) |
| { |
| *length = symbaton->size; |
| *start = symbaton->data; |
| } |
| else |
| *start = NULL; |
| } |
| |
| if (*start == NULL) |
| error (_("Could not find the frame base for \"%s\"."), |
| SYMBOL_NATURAL_NAME (framefunc)); |
| } |
| |
| /* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for |
| the frame in BATON. */ |
| |
| static CORE_ADDR |
| dwarf_expr_frame_cfa (void *baton) |
| { |
| struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
| |
| return dwarf2_frame_cfa (debaton->frame); |
| } |
| |
| /* Helper function for dwarf2_evaluate_loc_desc. Computes the PC for |
| the frame in BATON. */ |
| |
| static CORE_ADDR |
| dwarf_expr_frame_pc (void *baton) |
| { |
| struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
| |
| return get_frame_address_in_block (debaton->frame); |
| } |
| |
| /* Using the objfile specified in BATON, find the address for the |
| current thread's thread-local storage with offset OFFSET. */ |
| static CORE_ADDR |
| dwarf_expr_tls_address (void *baton, CORE_ADDR offset) |
| { |
| struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton; |
| struct objfile *objfile = dwarf2_per_cu_objfile (debaton->per_cu); |
| |
| return target_translate_tls_address (objfile, offset); |
| } |
| |
| /* Call DWARF subroutine from DW_AT_location of DIE at DIE_OFFSET in |
| current CU (as is PER_CU). State of the CTX is not affected by the |
| call and return. */ |
| |
| static void |
| per_cu_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset, |
| struct dwarf2_per_cu_data *per_cu, |
| CORE_ADDR (*get_frame_pc) (void *baton), |
| void *baton) |
| { |
| struct dwarf2_locexpr_baton block; |
| |
| block = dwarf2_fetch_die_location_block (die_offset, per_cu, |
| get_frame_pc, baton); |
| |
| /* DW_OP_call_ref is currently not supported. */ |
| gdb_assert (block.per_cu == per_cu); |
| |
| dwarf_expr_eval (ctx, block.data, block.size); |
| } |
| |
| /* Helper interface of per_cu_dwarf_call for dwarf2_evaluate_loc_desc. */ |
| |
| static void |
| dwarf_expr_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset) |
| { |
| struct dwarf_expr_baton *debaton = ctx->baton; |
| |
| per_cu_dwarf_call (ctx, die_offset, debaton->per_cu, |
| ctx->get_frame_pc, ctx->baton); |
| } |
| |
| struct piece_closure |
| { |
| /* Reference count. */ |
| int refc; |
| |
| /* The CU from which this closure's expression came. */ |
| struct dwarf2_per_cu_data *per_cu; |
| |
| /* The number of pieces used to describe this variable. */ |
| int n_pieces; |
| |
| /* The target address size, used only for DWARF_VALUE_STACK. */ |
| int addr_size; |
| |
| /* The pieces themselves. */ |
| struct dwarf_expr_piece *pieces; |
| }; |
| |
| /* Allocate a closure for a value formed from separately-described |
| PIECES. */ |
| |
| static struct piece_closure * |
| allocate_piece_closure (struct dwarf2_per_cu_data *per_cu, |
| int n_pieces, struct dwarf_expr_piece *pieces, |
| int addr_size) |
| { |
| struct piece_closure *c = XZALLOC (struct piece_closure); |
| |
| c->refc = 1; |
| c->per_cu = per_cu; |
| c->n_pieces = n_pieces; |
| c->addr_size = addr_size; |
| c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece); |
| |
| memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece)); |
| |
| return c; |
| } |
| |
| /* The lowest-level function to extract bits from a byte buffer. |
| SOURCE is the buffer. It is updated if we read to the end of a |
| byte. |
| SOURCE_OFFSET_BITS is the offset of the first bit to read. It is |
| updated to reflect the number of bits actually read. |
| NBITS is the number of bits we want to read. It is updated to |
| reflect the number of bits actually read. This function may read |
| fewer bits. |
| BITS_BIG_ENDIAN is taken directly from gdbarch. |
| This function returns the extracted bits. */ |
| |
| static unsigned int |
| extract_bits_primitive (const gdb_byte **source, |
| unsigned int *source_offset_bits, |
| int *nbits, int bits_big_endian) |
| { |
| unsigned int avail, mask, datum; |
| |
| gdb_assert (*source_offset_bits < 8); |
| |
| avail = 8 - *source_offset_bits; |
| if (avail > *nbits) |
| avail = *nbits; |
| |
| mask = (1 << avail) - 1; |
| datum = **source; |
| if (bits_big_endian) |
| datum >>= 8 - (*source_offset_bits + *nbits); |
| else |
| datum >>= *source_offset_bits; |
| datum &= mask; |
| |
| *nbits -= avail; |
| *source_offset_bits += avail; |
| if (*source_offset_bits >= 8) |
| { |
| *source_offset_bits -= 8; |
| ++*source; |
| } |
| |
| return datum; |
| } |
| |
| /* Extract some bits from a source buffer and move forward in the |
| buffer. |
| |
| SOURCE is the source buffer. It is updated as bytes are read. |
| SOURCE_OFFSET_BITS is the offset into SOURCE. It is updated as |
| bits are read. |
| NBITS is the number of bits to read. |
| BITS_BIG_ENDIAN is taken directly from gdbarch. |
| |
| This function returns the bits that were read. */ |
| |
| static unsigned int |
| extract_bits (const gdb_byte **source, unsigned int *source_offset_bits, |
| int nbits, int bits_big_endian) |
| { |
| unsigned int datum; |
| |
| gdb_assert (nbits > 0 && nbits <= 8); |
| |
| datum = extract_bits_primitive (source, source_offset_bits, &nbits, |
| bits_big_endian); |
| if (nbits > 0) |
| { |
| unsigned int more; |
| |
| more = extract_bits_primitive (source, source_offset_bits, &nbits, |
| bits_big_endian); |
| if (bits_big_endian) |
| datum <<= nbits; |
| else |
| more <<= nbits; |
| datum |= more; |
| } |
| |
| return datum; |
| } |
| |
| /* Write some bits into a buffer and move forward in the buffer. |
| |
| DATUM is the bits to write. The low-order bits of DATUM are used. |
| DEST is the destination buffer. It is updated as bytes are |
| written. |
| DEST_OFFSET_BITS is the bit offset in DEST at which writing is |
| done. |
| NBITS is the number of valid bits in DATUM. |
| BITS_BIG_ENDIAN is taken directly from gdbarch. */ |
| |
| static void |
| insert_bits (unsigned int datum, |
| gdb_byte *dest, unsigned int dest_offset_bits, |
| int nbits, int bits_big_endian) |
| { |
| unsigned int mask; |
| |
| gdb_assert (dest_offset_bits + nbits <= 8); |
| |
| mask = (1 << nbits) - 1; |
| if (bits_big_endian) |
| { |
| datum <<= 8 - (dest_offset_bits + nbits); |
| mask <<= 8 - (dest_offset_bits + nbits); |
| } |
| else |
| { |
| datum <<= dest_offset_bits; |
| mask <<= dest_offset_bits; |
| } |
| |
| gdb_assert ((datum & ~mask) == 0); |
| |
| *dest = (*dest & ~mask) | datum; |
| } |
| |
| /* Copy bits from a source to a destination. |
| |
| DEST is where the bits should be written. |
| DEST_OFFSET_BITS is the bit offset into DEST. |
| SOURCE is the source of bits. |
| SOURCE_OFFSET_BITS is the bit offset into SOURCE. |
| BIT_COUNT is the number of bits to copy. |
| BITS_BIG_ENDIAN is taken directly from gdbarch. */ |
| |
| static void |
| copy_bitwise (gdb_byte *dest, unsigned int dest_offset_bits, |
| const gdb_byte *source, unsigned int source_offset_bits, |
| unsigned int bit_count, |
| int bits_big_endian) |
| { |
| unsigned int dest_avail; |
| int datum; |
| |
| /* Reduce everything to byte-size pieces. */ |
| dest += dest_offset_bits / 8; |
| dest_offset_bits %= 8; |
| source += source_offset_bits / 8; |
| source_offset_bits %= 8; |
| |
| dest_avail = 8 - dest_offset_bits % 8; |
| |
| /* See if we can fill the first destination byte. */ |
| if (dest_avail < bit_count) |
| { |
| datum = extract_bits (&source, &source_offset_bits, dest_avail, |
| bits_big_endian); |
| insert_bits (datum, dest, dest_offset_bits, dest_avail, bits_big_endian); |
| ++dest; |
| dest_offset_bits = 0; |
| bit_count -= dest_avail; |
| } |
| |
| /* Now, either DEST_OFFSET_BITS is byte-aligned, or we have fewer |
| than 8 bits remaining. */ |
| gdb_assert (dest_offset_bits % 8 == 0 || bit_count < 8); |
| for (; bit_count >= 8; bit_count -= 8) |
| { |
| datum = extract_bits (&source, &source_offset_bits, 8, bits_big_endian); |
| *dest++ = (gdb_byte) datum; |
| } |
| |
| /* Finally, we may have a few leftover bits. */ |
| gdb_assert (bit_count <= 8 - dest_offset_bits % 8); |
| if (bit_count > 0) |
| { |
| datum = extract_bits (&source, &source_offset_bits, bit_count, |
| bits_big_endian); |
| insert_bits (datum, dest, dest_offset_bits, bit_count, bits_big_endian); |
| } |
| } |
| |
| static void |
| read_pieced_value (struct value *v) |
| { |
| int i; |
| long offset = 0; |
| ULONGEST bits_to_skip; |
| gdb_byte *contents; |
| struct piece_closure *c |
| = (struct piece_closure *) value_computed_closure (v); |
| struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v)); |
| 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 (v))); |
| |
| if (value_type (v) != value_enclosing_type (v)) |
| internal_error (__FILE__, __LINE__, |
| _("Should not be able to create a lazy value with " |
| "an enclosing type")); |
| |
| cleanup = make_cleanup (free_current_contents, &buffer); |
| |
| contents = value_contents_raw (v); |
| bits_to_skip = 8 * value_offset (v); |
| if (value_bitsize (v)) |
| { |
| bits_to_skip += value_bitpos (v); |
| type_len = value_bitsize (v); |
| } |
| else |
| type_len = 8 * TYPE_LENGTH (value_type (v)); |
| |
| for (i = 0; i < c->n_pieces && offset < type_len; i++) |
| { |
| struct dwarf_expr_piece *p = &c->pieces[i]; |
| size_t this_size, this_size_bits; |
| long dest_offset_bits, source_offset_bits, source_offset; |
| const gdb_byte *intermediate_buffer; |
| |
| /* Compute size, source, and destination offsets for copying, in |
| bits. */ |
| 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 = 0; |
| source_offset_bits = bits_to_skip; |
| this_size_bits -= bits_to_skip; |
| bits_to_skip = 0; |
| } |
| else |
| { |
| dest_offset_bits = offset; |
| source_offset_bits = 0; |
| } |
| |
| 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.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) |
| { |
| int optim, unavail; |
| |
| if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset, |
| this_size, buffer, |
| &optim, &unavail)) |
| { |
| /* Just so garbage doesn't ever shine through. */ |
| memset (buffer, 0, this_size); |
| |
| if (optim) |
| set_value_optimized_out (v, 1); |
| if (unavail) |
| mark_value_bytes_unavailable (v, offset, this_size); |
| } |
| } |
| else |
| { |
| error (_("Unable to access DWARF register number %s"), |
| paddress (arch, p->v.value)); |
| } |
| } |
| break; |
| |
| case DWARF_VALUE_MEMORY: |
| read_value_memory (v, offset, |
| p->v.mem.in_stack_memory, |
| p->v.mem.addr + 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.value); |
| else |
| { |
| gdb_byte bytes[sizeof (ULONGEST)]; |
| |
| store_unsigned_integer (bytes, n + source_offset, |
| gdbarch_byte_order (gdbarch), |
| p->v.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; |
| |
| /* These bits show up as zeros -- but do not cause the value |
| to be considered optimized-out. */ |
| case DWARF_VALUE_IMPLICIT_POINTER: |
| break; |
| |
| case DWARF_VALUE_OPTIMIZED_OUT: |
| set_value_optimized_out (v, 1); |
| break; |
| |
| default: |
| internal_error (__FILE__, __LINE__, _("invalid location type")); |
| } |
| |
| if (p->location != DWARF_VALUE_OPTIMIZED_OUT |
| && p->location != DWARF_VALUE_IMPLICIT_POINTER) |
| 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); |
| if (value_bitsize (to)) |
| { |
| bits_to_skip += value_bitpos (to); |
| type_len = value_bitsize (to); |
| } |
| else |
| 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.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) |
| { |
| int optim, unavail; |
| |
| if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset, |
| this_size, buffer, |
| &optim, &unavail)) |
| { |
| if (optim) |
| error (_("Can't do read-modify-write to " |
| "update bitfield; containing word has been " |
| "optimized out")); |
| if (unavail) |
| throw_error (NOT_AVAILABLE_ERROR, |
| _("Can't do read-modify-write to update " |
| "bitfield; containing word " |
| "is unavailable")); |
| } |
| 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.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.mem.addr + dest_offset, buffer, 1); |
| read_memory (p->v.mem.addr + 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.mem.addr + dest_offset, |
| source_buffer, this_size); |
| break; |
| default: |
| set_value_optimized_out (to, 1); |
| break; |
| } |
| offset += this_size_bits; |
| } |
| |
| do_cleanups (cleanup); |
| } |
| |
| /* A helper function that checks bit validity in a pieced value. |
| CHECK_FOR indicates the kind of validity checking. |
| DWARF_VALUE_MEMORY means to check whether any bit is valid. |
| DWARF_VALUE_OPTIMIZED_OUT means to check whether any bit is |
| optimized out. |
| DWARF_VALUE_IMPLICIT_POINTER means to check whether the bits are an |
| implicit pointer. */ |
| |
| static int |
| check_pieced_value_bits (const struct value *value, int bit_offset, |
| int bit_length, |
| enum dwarf_value_location check_for) |
| { |
| struct piece_closure *c |
| = (struct piece_closure *) value_computed_closure (value); |
| int i; |
| int validity = (check_for == DWARF_VALUE_MEMORY |
| || check_for == DWARF_VALUE_IMPLICIT_POINTER); |
| |
| bit_offset += 8 * value_offset (value); |
| if (value_bitsize (value)) |
| bit_offset += value_bitpos (value); |
| |
| for (i = 0; i < c->n_pieces && bit_length > 0; i++) |
| { |
| struct dwarf_expr_piece *p = &c->pieces[i]; |
| size_t this_size_bits = p->size; |
| |
| if (bit_offset > 0) |
| { |
| if (bit_offset >= this_size_bits) |
| { |
| bit_offset -= this_size_bits; |
| continue; |
| } |
| |
| bit_length -= this_size_bits - bit_offset; |
| bit_offset = 0; |
| } |
| else |
| bit_length -= this_size_bits; |
| |
| if (check_for == DWARF_VALUE_IMPLICIT_POINTER) |
| { |
| if (p->location != DWARF_VALUE_IMPLICIT_POINTER) |
| return 0; |
| } |
| else if (p->location == DWARF_VALUE_OPTIMIZED_OUT |
| || p->location == DWARF_VALUE_IMPLICIT_POINTER) |
| { |
| if (validity) |
| return 0; |
| } |
| else |
| { |
| if (!validity) |
| return 1; |
| } |
| } |
| |
| return validity; |
| } |
| |
| static int |
| check_pieced_value_validity (const struct value *value, int bit_offset, |
| int bit_length) |
| { |
| return check_pieced_value_bits (value, bit_offset, bit_length, |
| DWARF_VALUE_MEMORY); |
| } |
| |
| static int |
| check_pieced_value_invalid (const struct value *value) |
| { |
| return check_pieced_value_bits (value, 0, |
| 8 * TYPE_LENGTH (value_type (value)), |
| DWARF_VALUE_OPTIMIZED_OUT); |
| } |
| |
| /* An implementation of an lval_funcs method to see whether a value is |
| a synthetic pointer. */ |
| |
| static int |
| check_pieced_synthetic_pointer (const struct value *value, int bit_offset, |
| int bit_length) |
| { |
| return check_pieced_value_bits (value, bit_offset, bit_length, |
| DWARF_VALUE_IMPLICIT_POINTER); |
| } |
| |
| /* A wrapper function for get_frame_address_in_block. */ |
| |
| static CORE_ADDR |
| get_frame_address_in_block_wrapper (void *baton) |
| { |
| return get_frame_address_in_block (baton); |
| } |
| |
| /* An implementation of an lval_funcs method to indirect through a |
| pointer. This handles the synthetic pointer case when needed. */ |
| |
| static struct value * |
| indirect_pieced_value (struct value *value) |
| { |
| struct piece_closure *c |
| = (struct piece_closure *) value_computed_closure (value); |
| struct type *type; |
| struct frame_info *frame; |
| struct dwarf2_locexpr_baton baton; |
| int i, bit_offset, bit_length; |
| struct dwarf_expr_piece *piece = NULL; |
| struct value *result; |
| LONGEST byte_offset; |
| |
| type = value_type (value); |
| if (TYPE_CODE (type) != TYPE_CODE_PTR) |
| return NULL; |
| |
| bit_length = 8 * TYPE_LENGTH (type); |
| bit_offset = 8 * value_offset (value); |
| if (value_bitsize (value)) |
| bit_offset += value_bitpos (value); |
| |
| for (i = 0; i < c->n_pieces && bit_length > 0; i++) |
| { |
| struct dwarf_expr_piece *p = &c->pieces[i]; |
| size_t this_size_bits = p->size; |
| |
| if (bit_offset > 0) |
| { |
| if (bit_offset >= this_size_bits) |
| { |
| bit_offset -= this_size_bits; |
| continue; |
| } |
| |
| bit_length -= this_size_bits - bit_offset; |
| bit_offset = 0; |
| } |
| else |
| bit_length -= this_size_bits; |
| |
| if (p->location != DWARF_VALUE_IMPLICIT_POINTER) |
| return NULL; |
| |
| if (bit_length != 0) |
| error (_("Invalid use of DW_OP_GNU_implicit_pointer")); |
| |
| piece = p; |
| break; |
| } |
| |
| frame = get_selected_frame (_("No frame selected.")); |
| byte_offset = value_as_address (value); |
| |
| gdb_assert (piece); |
| baton = dwarf2_fetch_die_location_block (piece->v.ptr.die, c->per_cu, |
| get_frame_address_in_block_wrapper, |
| frame); |
| |
| result = dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame, |
| baton.data, baton.size, baton.per_cu, |
| byte_offset); |
| |
| return result; |
| } |
| |
| static void * |
| copy_pieced_value_closure (const 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, |
| check_pieced_value_validity, |
| check_pieced_value_invalid, |
| indirect_pieced_value, |
| check_pieced_synthetic_pointer, |
| copy_pieced_value_closure, |
| free_pieced_value_closure |
| }; |
| |
| /* Helper function which throws an error if a synthetic pointer is |
| invalid. */ |
| |
| static void |
| invalid_synthetic_pointer (void) |
| { |
| error (_("access outside bounds of object " |
| "referenced via synthetic pointer")); |
| } |
| |
| /* 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. BYTE_OFFSET is applied after the contents are |
| computed. */ |
| |
| static struct value * |
| dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame, |
| const gdb_byte *data, unsigned short size, |
| struct dwarf2_per_cu_data *per_cu, |
| LONGEST byte_offset) |
| { |
| struct value *retval; |
| struct dwarf_expr_baton baton; |
| struct dwarf_expr_context *ctx; |
| struct cleanup *old_chain; |
| struct objfile *objfile = dwarf2_per_cu_objfile (per_cu); |
| volatile struct gdb_exception ex; |
| |
| if (byte_offset < 0) |
| invalid_synthetic_pointer (); |
| |
| if (size == 0) |
| { |
| retval = allocate_value (type); |
| VALUE_LVAL (retval) = not_lval; |
| set_value_optimized_out (retval, 1); |
| return retval; |
| } |
| |
| baton.frame = frame; |
| baton.per_cu = per_cu; |
| |
| ctx = new_dwarf_expr_context (); |
| old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
| |
| ctx->gdbarch = get_objfile_arch (objfile); |
| ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
| ctx->offset = dwarf2_per_cu_text_offset (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_frame_pc = dwarf_expr_frame_pc; |
| ctx->get_tls_address = dwarf_expr_tls_address; |
| ctx->dwarf_call = dwarf_expr_dwarf_call; |
| |
| TRY_CATCH (ex, RETURN_MASK_ERROR) |
| { |
| dwarf_expr_eval (ctx, data, size); |
| } |
| if (ex.reason < 0) |
| { |
| if (ex.error == NOT_AVAILABLE_ERROR) |
| { |
| retval = allocate_value (type); |
| mark_value_bytes_unavailable (retval, 0, TYPE_LENGTH (type)); |
| return retval; |
| } |
| else |
| throw_exception (ex); |
| } |
| |
| if (ctx->num_pieces > 0) |
| { |
| struct piece_closure *c; |
| struct frame_id frame_id = get_frame_id (frame); |
| ULONGEST bit_size = 0; |
| int i; |
| |
| for (i = 0; i < ctx->num_pieces; ++i) |
| bit_size += ctx->pieces[i].size; |
| if (8 * (byte_offset + TYPE_LENGTH (type)) > bit_size) |
| invalid_synthetic_pointer (); |
| |
| c = allocate_piece_closure (per_cu, ctx->num_pieces, ctx->pieces, |
| ctx->addr_size); |
| retval = allocate_computed_value (type, &pieced_value_funcs, c); |
| VALUE_FRAME_ID (retval) = frame_id; |
| set_value_offset (retval, byte_offset); |
| } |
| else |
| { |
| switch (ctx->location) |
| { |
| case DWARF_VALUE_REGISTER: |
| { |
| struct gdbarch *arch = get_frame_arch (frame); |
| ULONGEST dwarf_regnum = dwarf_expr_fetch (ctx, 0); |
| int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum); |
| |
| if (byte_offset != 0) |
| error (_("cannot use offset on synthetic pointer to register")); |
| 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_address (ctx, 0); |
| int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0); |
| |
| retval = allocate_value_lazy (type); |
| VALUE_LVAL (retval) = lval_memory; |
| if (in_stack_memory) |
| set_value_stack (retval, 1); |
| set_value_address (retval, address + byte_offset); |
| } |
| break; |
| |
| case DWARF_VALUE_STACK: |
| { |
| ULONGEST value = dwarf_expr_fetch (ctx, 0); |
| bfd_byte *contents, *tem; |
| size_t n = ctx->addr_size; |
| |
| if (byte_offset + TYPE_LENGTH (type) > n) |
| invalid_synthetic_pointer (); |
| |
| tem = alloca (n); |
| store_unsigned_integer (tem, n, |
| gdbarch_byte_order (ctx->gdbarch), |
| value); |
| |
| tem += byte_offset; |
| n -= byte_offset; |
| |
| retval = allocate_value (type); |
| contents = value_contents_raw (retval); |
| if (n > TYPE_LENGTH (type)) |
| n = TYPE_LENGTH (type); |
| memcpy (contents, tem, n); |
| } |
| break; |
| |
| case DWARF_VALUE_LITERAL: |
| { |
| bfd_byte *contents; |
| const bfd_byte *ldata; |
| size_t n = ctx->len; |
| |
| if (byte_offset + TYPE_LENGTH (type) > n) |
| invalid_synthetic_pointer (); |
| |
| retval = allocate_value (type); |
| contents = value_contents_raw (retval); |
| |
| ldata = ctx->data + byte_offset; |
| n -= byte_offset; |
| |
| if (n > TYPE_LENGTH (type)) |
| n = TYPE_LENGTH (type); |
| memcpy (contents, ldata, n); |
| } |
| break; |
| |
| case DWARF_VALUE_OPTIMIZED_OUT: |
| retval = allocate_value (type); |
| VALUE_LVAL (retval) = not_lval; |
| set_value_optimized_out (retval, 1); |
| break; |
| |
| /* DWARF_VALUE_IMPLICIT_POINTER was converted to a pieced |
| operation by execute_stack_op. */ |
| case DWARF_VALUE_IMPLICIT_POINTER: |
| /* DWARF_VALUE_OPTIMIZED_OUT can't occur in this context -- |
| it can only be encountered when making a piece. */ |
| default: |
| internal_error (__FILE__, __LINE__, _("invalid location type")); |
| } |
| } |
| |
| set_value_initialized (retval, ctx->initialized); |
| |
| do_cleanups (old_chain); |
| |
| return retval; |
| } |
| |
| /* The exported interface to dwarf2_evaluate_loc_desc_full; it always |
| passes 0 as the byte_offset. */ |
| |
| 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) |
| { |
| return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu, 0); |
| } |
| |
| |
| /* Helper functions and baton for dwarf2_loc_desc_needs_frame. */ |
| |
| struct needs_frame_baton |
| { |
| int needs_frame; |
| struct dwarf2_per_cu_data *per_cu; |
| }; |
| |
| /* 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; |
| } |
| |
| /* Helper interface of per_cu_dwarf_call for dwarf2_loc_desc_needs_frame. */ |
| |
| static void |
| needs_frame_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset) |
| { |
| struct needs_frame_baton *nf_baton = ctx->baton; |
| |
| per_cu_dwarf_call (ctx, die_offset, nf_baton->per_cu, |
| ctx->get_frame_pc, ctx->baton); |
| } |
| |
| /* 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; |
| struct objfile *objfile = dwarf2_per_cu_objfile (per_cu); |
| |
| baton.needs_frame = 0; |
| baton.per_cu = per_cu; |
| |
| ctx = new_dwarf_expr_context (); |
| old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
| |
| ctx->gdbarch = get_objfile_arch (objfile); |
| ctx->addr_size = dwarf2_per_cu_addr_size (per_cu); |
| ctx->offset = dwarf2_per_cu_text_offset (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_frame_pc = needs_frame_frame_cfa; |
| ctx->get_tls_address = needs_frame_tls_address; |
| ctx->dwarf_call = needs_frame_dwarf_call; |
| |
| 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; |
| } |
| |
| /* A helper function that throws an unimplemented error mentioning a |
| given DWARF operator. */ |
| |
| static void |
| unimplemented (unsigned int op) |
| { |
| const char *name = dwarf_stack_op_name (op); |
| |
| if (name) |
| error (_("DWARF operator %s cannot be translated to an agent expression"), |
| name); |
| else |
| error (_("Unknown DWARF operator 0x%02x cannot be translated " |
| "to an agent expression"), |
| op); |
| } |
| |
| /* A helper function to convert a DWARF register to an arch register. |
| ARCH is the architecture. |
| DWARF_REG is the register. |
| This will throw an exception if the DWARF register cannot be |
| translated to an architecture register. */ |
| |
| static int |
| translate_register (struct gdbarch *arch, int dwarf_reg) |
| { |
| int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg); |
| if (reg == -1) |
| error (_("Unable to access DWARF register number %d"), dwarf_reg); |
| return reg; |
| } |
| |
| /* A helper function that emits an access to memory. ARCH is the |
| target architecture. EXPR is the expression which we are building. |
| NBITS is the number of bits we want to read. This emits the |
| opcodes needed to read the memory and then extract the desired |
| bits. */ |
| |
| static void |
| access_memory (struct gdbarch *arch, struct agent_expr *expr, ULONGEST nbits) |
| { |
| ULONGEST nbytes = (nbits + 7) / 8; |
| |
| gdb_assert (nbits > 0 && nbits <= sizeof (LONGEST)); |
| |
| if (trace_kludge) |
| ax_trace_quick (expr, nbytes); |
| |
| if (nbits <= 8) |
| ax_simple (expr, aop_ref8); |
| else if (nbits <= 16) |
| ax_simple (expr, aop_ref16); |
| else if (nbits <= 32) |
| ax_simple (expr, aop_ref32); |
| else |
| ax_simple (expr, aop_ref64); |
| |
| /* If we read exactly the number of bytes we wanted, we're done. */ |
| if (8 * nbytes == nbits) |
| return; |
| |
| if (gdbarch_bits_big_endian (arch)) |
| { |
| /* On a bits-big-endian machine, we want the high-order |
| NBITS. */ |
| ax_const_l (expr, 8 * nbytes - nbits); |
| ax_simple (expr, aop_rsh_unsigned); |
| } |
| else |
| { |
| /* On a bits-little-endian box, we want the low-order NBITS. */ |
| ax_zero_ext (expr, nbits); |
| } |
| } |
| |
| /* A helper function to return the frame's PC. */ |
| |
| static CORE_ADDR |
| get_ax_pc (void *baton) |
| { |
| struct agent_expr *expr = baton; |
| |
| return expr->scope; |
| } |
| |
| /* Compile a DWARF location expression to an agent expression. |
| |
| EXPR is the agent expression we are building. |
| LOC is the agent value we modify. |
| ARCH is the architecture. |
| ADDR_SIZE is the size of addresses, in bytes. |
| OP_PTR is the start of the location expression. |
| OP_END is one past the last byte of the location expression. |
| |
| This will throw an exception for various kinds of errors -- for |
| example, if the expression cannot be compiled, or if the expression |
| is invalid. */ |
| |
| void |
| dwarf2_compile_expr_to_ax (struct agent_expr *expr, struct axs_value *loc, |
| struct gdbarch *arch, unsigned int addr_size, |
| const gdb_byte *op_ptr, const gdb_byte *op_end, |
| struct dwarf2_per_cu_data *per_cu) |
| { |
| struct cleanup *cleanups; |
| int i, *offsets; |
| VEC(int) *dw_labels = NULL, *patches = NULL; |
| const gdb_byte * const base = op_ptr; |
| const gdb_byte *previous_piece = op_ptr; |
| enum bfd_endian byte_order = gdbarch_byte_order (arch); |
| ULONGEST bits_collected = 0; |
| unsigned int addr_size_bits = 8 * addr_size; |
| int bits_big_endian = gdbarch_bits_big_endian (arch); |
| |
| offsets = xmalloc ((op_end - op_ptr) * sizeof (int)); |
| cleanups = make_cleanup (xfree, offsets); |
| |
| for (i = 0; i < op_end - op_ptr; ++i) |
| offsets[i] = -1; |
| |
| make_cleanup (VEC_cleanup (int), &dw_labels); |
| make_cleanup (VEC_cleanup (int), &patches); |
| |
| /* By default we are making an address. */ |
| loc->kind = axs_lvalue_memory; |
| |
| while (op_ptr < op_end) |
| { |
| enum dwarf_location_atom op = *op_ptr; |
| ULONGEST uoffset, reg; |
| LONGEST offset; |
| int i; |
| |
| offsets[op_ptr - base] = expr->len; |
| ++op_ptr; |
| |
| /* Our basic approach to code generation is to map DWARF |
| operations directly to AX operations. However, there are |
| some differences. |
| |
| First, DWARF works on address-sized units, but AX always uses |
| LONGEST. For most operations we simply ignore this |
| difference; instead we generate sign extensions as needed |
| before division and comparison operations. It would be nice |
| to omit the sign extensions, but there is no way to determine |
| the size of the target's LONGEST. (This code uses the size |
| of the host LONGEST in some cases -- that is a bug but it is |
| difficult to fix.) |
| |
| Second, some DWARF operations cannot be translated to AX. |
| For these we simply fail. See |
| http://sourceware.org/bugzilla/show_bug.cgi?id=11662. */ |
| switch (op) |
| { |
| case DW_OP_lit0: |
| case DW_OP_lit1: |
| case DW_OP_lit2: |
| case DW_OP_lit3: |
| case DW_OP_lit4: |
| case DW_OP_lit5: |
| case DW_OP_lit6: |
| case DW_OP_lit7: |
| case DW_OP_lit8: |
| case DW_OP_lit9: |
| case DW_OP_lit10: |
| case DW_OP_lit11: |
| case DW_OP_lit12: |
| case DW_OP_lit13: |
| case DW_OP_lit14: |
| case DW_OP_lit15: |
| case DW_OP_lit16: |
| case DW_OP_lit17: |
| case DW_OP_lit18: |
| case DW_OP_lit19: |
| case DW_OP_lit20: |
| case DW_OP_lit21: |
| case DW_OP_lit22: |
| case DW_OP_lit23: |
| case DW_OP_lit24: |
| case DW_OP_lit25: |
| case DW_OP_lit26: |
| case DW_OP_lit27: |
| case DW_OP_lit28: |
| case DW_OP_lit29: |
| case DW_OP_lit30: |
| case DW_OP_lit31: |
| ax_const_l (expr, op - DW_OP_lit0); |
| break; |
| |
| case DW_OP_addr: |
| uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order); |
| op_ptr += addr_size; |
| /* Some versions of GCC emit DW_OP_addr before |
| DW_OP_GNU_push_tls_address. In this case the value is an |
| index, not an address. We don't support things like |
| branching between the address and the TLS op. */ |
| if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address) |
| uoffset += dwarf2_per_cu_text_offset (per_cu); |
| ax_const_l (expr, uoffset); |
| break; |
| |
| case DW_OP_const1u: |
| ax_const_l (expr, extract_unsigned_integer (op_ptr, 1, byte_order)); |
| op_ptr += 1; |
| break; |
| case DW_OP_const1s: |
| ax_const_l (expr, extract_signed_integer (op_ptr, 1, byte_order)); |
| op_ptr += 1; |
| break; |
| case DW_OP_const2u: |
| ax_const_l (expr, extract_unsigned_integer (op_ptr, 2, byte_order)); |
| op_ptr += 2; |
| break; |
| case DW_OP_const2s: |
| ax_const_l (expr, extract_signed_integer (op_ptr, 2, byte_order)); |
| op_ptr += 2; |
| break; |
| case DW_OP_const4u: |
| ax_const_l (expr, extract_unsigned_integer (op_ptr, 4, byte_order)); |
| op_ptr += 4; |
| break; |
| case DW_OP_const4s: |
| ax_const_l (expr, extract_signed_integer (op_ptr, 4, byte_order)); |
| op_ptr += 4; |
| break; |
| case DW_OP_const8u: |
| ax_const_l (expr, extract_unsigned_integer (op_ptr, 8, byte_order)); |
| op_ptr += 8; |
| break; |
| case DW_OP_const8s: |
| ax_const_l (expr, extract_signed_integer (op_ptr, 8, byte_order)); |
| op_ptr += 8; |
| break; |
| case DW_OP_constu: |
| op_ptr = read_uleb128 (op_ptr, op_end, &uoffset); |
| ax_const_l (expr, uoffset); |
| break; |
| case DW_OP_consts: |
| op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| ax_const_l (expr, offset); |
| 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: |
| dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx"); |
| loc->u.reg = translate_register (arch, op - DW_OP_reg0); |
| loc->kind = axs_lvalue_register; |
| break; |
| |
| case DW_OP_regx: |
| op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx"); |
| loc->u.reg = translate_register (arch, reg); |
| loc->kind = axs_lvalue_register; |
| break; |
| |
| case DW_OP_implicit_value: |
| { |
| ULONGEST len; |
| |
| op_ptr = read_uleb128 (op_ptr, op_end, &len); |
| if (op_ptr + len > op_end) |
| error (_("DW_OP_implicit_value: too few bytes available.")); |
| if (len > sizeof (ULONGEST)) |
| error (_("Cannot translate DW_OP_implicit_value of %d bytes"), |
| (int) len); |
| |
| ax_const_l (expr, extract_unsigned_integer (op_ptr, len, |
| byte_order)); |
| op_ptr += len; |
| dwarf_expr_require_composition (op_ptr, op_end, |
| "DW_OP_implicit_value"); |
| |
| loc->kind = axs_rvalue; |
| } |
| break; |
| |
| case DW_OP_stack_value: |
| dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value"); |
| loc->kind = axs_rvalue; |
| 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: |
| op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| i = translate_register (arch, op - DW_OP_breg0); |
| ax_reg (expr, i); |
| if (offset != 0) |
| { |
| ax_const_l (expr, offset); |
| ax_simple (expr, aop_add); |
| } |
| break; |
| case DW_OP_bregx: |
| { |
| op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| i = translate_register (arch, reg); |
| ax_reg (expr, i); |
| if (offset != 0) |
| { |
| ax_const_l (expr, offset); |
| ax_simple (expr, aop_add); |
| } |
| } |
| break; |
| case DW_OP_fbreg: |
| { |
| const gdb_byte *datastart; |
| size_t datalen; |
| unsigned int before_stack_len; |
| struct block *b; |
| struct symbol *framefunc; |
| LONGEST base_offset = 0; |
| |
| b = block_for_pc (expr->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, expr->scope, |
| &datastart, &datalen); |
| |
| op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, datastart, |
| datastart + datalen, per_cu); |
| |
| if (offset != 0) |
| { |
| ax_const_l (expr, offset); |
| ax_simple (expr, aop_add); |
| } |
| |
| loc->kind = axs_lvalue_memory; |
| } |
| break; |
| |
| case DW_OP_dup: |
| ax_simple (expr, aop_dup); |
| break; |
| |
| case DW_OP_drop: |
| ax_simple (expr, aop_pop); |
| break; |
| |
| case DW_OP_pick: |
| offset = *op_ptr++; |
| ax_pick (expr, offset); |
| break; |
| |
| case DW_OP_swap: |
| ax_simple (expr, aop_swap); |
| break; |
| |
| case DW_OP_over: |
| ax_pick (expr, 1); |
| break; |
| |
| case DW_OP_rot: |
| ax_simple (expr, aop_rot); |
| break; |
| |
| case DW_OP_deref: |
| case DW_OP_deref_size: |
| { |
| int size; |
| |
| if (op == DW_OP_deref_size) |
| size = *op_ptr++; |
| else |
| size = addr_size; |
| |
| switch (size) |
| { |
| case 8: |
| ax_simple (expr, aop_ref8); |
| break; |
| case 16: |
| ax_simple (expr, aop_ref16); |
| break; |
| case 32: |
| ax_simple (expr, aop_ref32); |
| break; |
| case 64: |
| ax_simple (expr, aop_ref64); |
| break; |
| default: |
| /* Note that dwarf_stack_op_name will never return |
| NULL here. */ |
| error (_("Unsupported size %d in %s"), |
| size, dwarf_stack_op_name (op)); |
| } |
| } |
| break; |
| |
| case DW_OP_abs: |
| /* Sign extend the operand. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_dup); |
| ax_const_l (expr, 0); |
| ax_simple (expr, aop_less_signed); |
| ax_simple (expr, aop_log_not); |
| i = ax_goto (expr, aop_if_goto); |
| /* We have to emit 0 - X. */ |
| ax_const_l (expr, 0); |
| ax_simple (expr, aop_swap); |
| ax_simple (expr, aop_sub); |
| ax_label (expr, i, expr->len); |
| break; |
| |
| case DW_OP_neg: |
| /* No need to sign extend here. */ |
| ax_const_l (expr, 0); |
| ax_simple (expr, aop_swap); |
| ax_simple (expr, aop_sub); |
| break; |
| |
| case DW_OP_not: |
| /* Sign extend the operand. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_bit_not); |
| break; |
| |
| case DW_OP_plus_uconst: |
| op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| /* It would be really weird to emit `DW_OP_plus_uconst 0', |
| but we micro-optimize anyhow. */ |
| if (reg != 0) |
| { |
| ax_const_l (expr, reg); |
| ax_simple (expr, aop_add); |
| } |
| break; |
| |
| case DW_OP_and: |
| ax_simple (expr, aop_bit_and); |
| break; |
| |
| case DW_OP_div: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_simple (expr, aop_div_signed); |
| break; |
| |
| case DW_OP_minus: |
| ax_simple (expr, aop_sub); |
| break; |
| |
| case DW_OP_mod: |
| ax_simple (expr, aop_rem_unsigned); |
| break; |
| |
| case DW_OP_mul: |
| ax_simple (expr, aop_mul); |
| break; |
| |
| case DW_OP_or: |
| ax_simple (expr, aop_bit_or); |
| break; |
| |
| case DW_OP_plus: |
| ax_simple (expr, aop_add); |
| break; |
| |
| case DW_OP_shl: |
| ax_simple (expr, aop_lsh); |
| break; |
| |
| case DW_OP_shr: |
| ax_simple (expr, aop_rsh_unsigned); |
| break; |
| |
| case DW_OP_shra: |
| ax_simple (expr, aop_rsh_signed); |
| break; |
| |
| case DW_OP_xor: |
| ax_simple (expr, aop_bit_xor); |
| break; |
| |
| case DW_OP_le: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| /* Note no swap here: A <= B is !(B < A). */ |
| ax_simple (expr, aop_less_signed); |
| ax_simple (expr, aop_log_not); |
| break; |
| |
| case DW_OP_ge: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| /* A >= B is !(A < B). */ |
| ax_simple (expr, aop_less_signed); |
| ax_simple (expr, aop_log_not); |
| break; |
| |
| case DW_OP_eq: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| /* No need for a second swap here. */ |
| ax_simple (expr, aop_equal); |
| break; |
| |
| case DW_OP_lt: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_simple (expr, aop_less_signed); |
| break; |
| |
| case DW_OP_gt: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| /* Note no swap here: A > B is B < A. */ |
| ax_simple (expr, aop_less_signed); |
| break; |
| |
| case DW_OP_ne: |
| /* Sign extend the operands. */ |
| ax_ext (expr, addr_size_bits); |
| ax_simple (expr, aop_swap); |
| ax_ext (expr, addr_size_bits); |
| /* No need for a swap here. */ |
| ax_simple (expr, aop_equal); |
| ax_simple (expr, aop_log_not); |
| break; |
| |
| case DW_OP_call_frame_cfa: |
| dwarf2_compile_cfa_to_ax (expr, loc, arch, expr->scope, per_cu); |
| loc->kind = axs_lvalue_memory; |
| break; |
| |
| case DW_OP_GNU_push_tls_address: |
| unimplemented (op); |
| break; |
| |
| case DW_OP_skip: |
| offset = extract_signed_integer (op_ptr, 2, byte_order); |
| op_ptr += 2; |
| i = ax_goto (expr, aop_goto); |
| VEC_safe_push (int, dw_labels, op_ptr + offset - base); |
| VEC_safe_push (int, patches, i); |
| break; |
| |
| case DW_OP_bra: |
| offset = extract_signed_integer (op_ptr, 2, byte_order); |
| op_ptr += 2; |
| /* Zero extend the operand. */ |
| ax_zero_ext (expr, addr_size_bits); |
| i = ax_goto (expr, aop_if_goto); |
| VEC_safe_push (int, dw_labels, op_ptr + offset - base); |
| VEC_safe_push (int, patches, i); |
| break; |
| |
| case DW_OP_nop: |
| break; |
| |
| case DW_OP_piece: |
| case DW_OP_bit_piece: |
| { |
| ULONGEST size, offset; |
| |
| if (op_ptr - 1 == previous_piece) |
| error (_("Cannot translate empty pieces to agent expressions")); |
| previous_piece = op_ptr - 1; |
| |
| op_ptr = read_uleb128 (op_ptr, op_end, &size); |
| if (op == DW_OP_piece) |
| { |
| size *= 8; |
| offset = 0; |
| } |
| else |
| op_ptr = read_uleb128 (op_ptr, op_end, &offset); |
| |
| if (bits_collected + size > 8 * sizeof (LONGEST)) |
| error (_("Expression pieces exceed word size")); |
| |
| /* Access the bits. */ |
| switch (loc->kind) |
| { |
| case axs_lvalue_register: |
| ax_reg (expr, loc->u.reg); |
| break; |
| |
| case axs_lvalue_memory: |
| /* Offset the pointer, if needed. */ |
| if (offset > 8) |
| { |
| ax_const_l (expr, offset / 8); |
| ax_simple (expr, aop_add); |
| offset %= 8; |
| } |
| access_memory (arch, expr, size); |
| break; |
| } |
| |
| /* For a bits-big-endian target, shift up what we already |
| have. For a bits-little-endian target, shift up the |
| new data. Note that there is a potential bug here if |
| the DWARF expression leaves multiple values on the |
| stack. */ |
| if (bits_collected > 0) |
| { |
| if (bits_big_endian) |
| { |
| ax_simple (expr, aop_swap); |
| ax_const_l (expr, size); |
| ax_simple (expr, aop_lsh); |
| /* We don't need a second swap here, because |
| aop_bit_or is symmetric. */ |
| } |
| else |
| { |
| ax_const_l (expr, size); |
| ax_simple (expr, aop_lsh); |
| } |
| ax_simple (expr, aop_bit_or); |
| } |
| |
| bits_collected += size; |
| loc->kind = axs_rvalue; |
| } |
| break; |
| |
| case DW_OP_GNU_uninit: |
| unimplemented (op); |
| |
| case DW_OP_call2: |
| case DW_OP_call4: |
| { |
| struct dwarf2_locexpr_baton block; |
| int size = (op == DW_OP_call2 ? 2 : 4); |
| |
| uoffset = extract_unsigned_integer (op_ptr, size, byte_order); |
| op_ptr += size; |
| |
| block = dwarf2_fetch_die_location_block (uoffset, per_cu, |
| get_ax_pc, expr); |
| |
| /* DW_OP_call_ref is currently not supported. */ |
| gdb_assert (block.per_cu == per_cu); |
| |
| dwarf2_compile_expr_to_ax (expr, loc, arch, addr_size, |
| block.data, block.data + block.size, |
| per_cu); |
| } |
| break; |
| |
| case DW_OP_call_ref: |
| unimplemented (op); |
| |
| default: |
| unimplemented (op); |
| } |
| } |
| |
| /* Patch all the branches we emitted. */ |
| for (i = 0; i < VEC_length (int, patches); ++i) |
| { |
| int targ = offsets[VEC_index (int, dw_labels, i)]; |
| if (targ == -1) |
| internal_error (__FILE__, __LINE__, _("invalid label")); |
| ax_label (expr, VEC_index (int, patches, i), targ); |
| } |
| |
| do_cleanups (cleanups); |
| } |
| |
| |
| /* 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, *save_data = 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. */ |
| return save_data; |
| } |
| |
| 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). Note that more recent version of GCC emit DW_OP_const4u |
| or DW_OP_const8u, depending on address size, rather than |
| DW_OP_addr. 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 |
| || (addr_size == 4 && data[0] == DW_OP_const4u) |
| || (addr_size == 8 && data[0] == DW_OP_const8u)) |
| && data[1 + addr_size] == DW_OP_GNU_push_tls_address |
| && piece_end_p (data + 2 + addr_size, end)) |
| { |
| ULONGEST offset; |
| offset = extract_unsigned_integer (data + 1, addr_size, |
| gdbarch_byte_order (gdbarch)); |
| |
| fprintf_filtered (stream, |
| _("a thread-local variable at offset 0x%s " |
| "in the thread-local storage for `%s'"), |
| phex_nz (offset, addr_size), 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++; |
| ULONGEST ul; |
| LONGEST l; |
| const char *name; |
| |
| name = dwarf_stack_op_name (op); |
| |
| 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: |
| ul = extract_unsigned_integer (data, addr_size, |
| gdbarch_byte_order (arch)); |
| data += addr_size; |
| fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size)); |
| 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, &l); |
| 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 [$%s]", pulongest (ul), |
| gdbarch_register_name (arch, (int) ul)); |
| break; |
| |
| case DW_OP_implicit_value: |
| data = read_uleb128 (data, end, &ul); |
| data += ul; |
| fprintf_filtered (stream, " %s", pulongest (ul)); |
| break; |
| |
| case DW_OP_breg0: |
| case DW_OP_breg1: |
| case DW_OP_breg2: |
| case DW_OP_breg3: |
| case DW_OP_breg4: |
| case DW_OP_breg5: |
| case DW_OP_breg6: |
| case DW_OP_breg7: |
| case DW_OP_breg8: |
| case DW_OP_breg9: |
| case DW_OP_breg10: |
| case DW_OP_breg11: |
| case DW_OP_breg12: |
| case DW_OP_breg13: |
| case DW_OP_breg14: |
| case DW_OP_breg15: |
| case DW_OP_breg16: |
| case DW_OP_breg17: |
| case DW_OP_breg18: |
| case DW_OP_breg19: |
| case DW_OP_breg20: |
| case DW_OP_breg21: |
| case DW_OP_breg22: |
| case DW_OP_breg23: |
| case DW_OP_breg24: |
| case DW_OP_breg25: |
| case DW_OP_breg26: |
| case DW_OP_breg27: |
| case DW_OP_breg28: |
| case DW_OP_breg29: |
| case DW_OP_breg30: |
| case DW_OP_breg31: |
| data = read_sleb128 (data, end, &l); |
| fprintf_filtered (stream, " %s [$%s]", plongest (l), |
| gdbarch_register_name (arch, op - DW_OP_breg0)); |
| break; |
| |
| case DW_OP_bregx: |
| data = read_uleb128 (data, end, &ul); |
| data = read_sleb128 (data, end, &l); |
| fprintf_filtered (stream, " register %s [$%s] offset %s", |
| pulongest (ul), |
| gdbarch_register_name (arch, (int) ul), |
| plongest (l)); |
| break; |
| |
| case DW_OP_fbreg: |
| data = read_sleb128 (data, end, &l); |
| fprintf_filtered (stream, " %s", plongest (l)); |
| 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; |
| |
| case DW_OP_GNU_implicit_pointer: |
| { |
| ul = extract_unsigned_integer (data, offset_size, |
| gdbarch_byte_order (arch)); |
| data += offset_size; |
| |
| data = read_sleb128 (data, end, &l); |
| |
| fprintf_filtered (stream, " DIE %s offset %s", |
| phex_nz (ul, offset_size), |
| plongest (l)); |
| } |
| 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); |
| unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); |
| |
| if (dlbaton->data == NULL || dlbaton->size == 0) |
| value->optimized_out = 1; |
| else |
| dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, |
| dlbaton->data, dlbaton->data + dlbaton->size, |
| dlbaton->per_cu); |
| } |
| |
| /* 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; |
| CORE_ADDR pc = frame ? get_frame_address_in_block (frame) : 0; |
| |
| data = dwarf2_find_location_expression (dlbaton, &size, pc); |
| 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); |
| int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd); |
| CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); |
| /* Adjust base_address for relocatable objects. */ |
| CORE_ADDR base_offset = dwarf2_per_cu_text_offset (dlbaton->per_cu); |
| 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)); |
| |
| if (signed_addr_p) |
| low = extract_signed_integer (loc_ptr, addr_size, byte_order); |
| else |
| low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
| loc_ptr += addr_size; |
| |
| if (signed_addr_p) |
| high = extract_signed_integer (loc_ptr, addr_size, byte_order); |
| else |
| high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); |
| loc_ptr += addr_size; |
| |
| /* A base-address-selection entry. */ |
| if ((low & base_mask) == base_mask) |
| { |
| base_address = high + base_offset; |
| fprintf_filtered (stream, _(" Base address %s"), |
| paddress (gdbarch, base_address)); |
| continue; |
| } |
| |
| /* 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; |
| unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); |
| |
| data = dwarf2_find_location_expression (dlbaton, &size, ax->scope); |
| if (data == NULL || size == 0) |
| value->optimized_out = 1; |
| else |
| dwarf2_compile_expr_to_ax (ax, value, gdbarch, addr_size, data, data + size, |
| dlbaton->per_cu); |
| } |
| |
| /* 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 |
| }; |