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- /* DWARF 2 Expression Evaluator.
- Copyright (C) 2001-2022 Free Software Foundation, Inc.
- Contributed by Daniel Berlin (dan@dberlin.org)
- 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 "block.h"
- #include "symtab.h"
- #include "gdbtypes.h"
- #include "value.h"
- #include "gdbcore.h"
- #include "dwarf2.h"
- #include "dwarf2/expr.h"
- #include "dwarf2/loc.h"
- #include "dwarf2/read.h"
- #include "frame.h"
- #include "gdbsupport/underlying.h"
- #include "gdbarch.h"
- #include "objfiles.h"
- /* Cookie for gdbarch data. */
- static struct gdbarch_data *dwarf_arch_cookie;
- /* This holds gdbarch-specific types used by the DWARF expression
- evaluator. See comments in execute_stack_op. */
- struct dwarf_gdbarch_types
- {
- struct type *dw_types[3];
- };
- /* Allocate and fill in dwarf_gdbarch_types for an arch. */
- static void *
- dwarf_gdbarch_types_init (struct gdbarch *gdbarch)
- {
- struct dwarf_gdbarch_types *types
- = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct dwarf_gdbarch_types);
- /* The types themselves are lazily initialized. */
- return types;
- }
- /* Ensure that a FRAME is defined, throw an exception otherwise. */
- static void
- ensure_have_frame (frame_info *frame, const char *op_name)
- {
- if (frame == nullptr)
- throw_error (GENERIC_ERROR,
- _("%s evaluation requires a frame."), op_name);
- }
- /* Ensure that a PER_CU is defined and throw an exception otherwise. */
- static void
- ensure_have_per_cu (dwarf2_per_cu_data *per_cu, const char* op_name)
- {
- if (per_cu == nullptr)
- throw_error (GENERIC_ERROR,
- _("%s evaluation requires a compilation unit."), op_name);
- }
- /* Return the number of bytes overlapping a contiguous chunk of N_BITS
- bits whose first bit is located at bit offset START. */
- static size_t
- bits_to_bytes (ULONGEST start, ULONGEST n_bits)
- {
- return (start % HOST_CHAR_BIT + n_bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
- }
- /* See expr.h. */
- CORE_ADDR
- read_addr_from_reg (frame_info *frame, int reg)
- {
- struct gdbarch *gdbarch = get_frame_arch (frame);
- int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
- return address_from_register (regnum, frame);
- }
- struct piece_closure
- {
- /* Reference count. */
- int refc = 0;
- /* The objfile from which this closure's expression came. */
- dwarf2_per_objfile *per_objfile = nullptr;
- /* The CU from which this closure's expression came. */
- dwarf2_per_cu_data *per_cu = nullptr;
- /* The pieces describing this variable. */
- std::vector<dwarf_expr_piece> pieces;
- /* Frame ID of frame to which a register value is relative, used
- only by DWARF_VALUE_REGISTER. */
- struct frame_id frame_id;
- };
- /* Allocate a closure for a value formed from separately-described
- PIECES. */
- static piece_closure *
- allocate_piece_closure (dwarf2_per_cu_data *per_cu,
- dwarf2_per_objfile *per_objfile,
- std::vector<dwarf_expr_piece> &&pieces,
- frame_info *frame)
- {
- piece_closure *c = new piece_closure;
- c->refc = 1;
- /* We must capture this here due to sharing of DWARF state. */
- c->per_objfile = per_objfile;
- c->per_cu = per_cu;
- c->pieces = std::move (pieces);
- if (frame == nullptr)
- c->frame_id = null_frame_id;
- else
- c->frame_id = get_frame_id (frame);
- for (dwarf_expr_piece &piece : c->pieces)
- if (piece.location == DWARF_VALUE_STACK)
- value_incref (piece.v.value);
- return c;
- }
- /* Read or write a pieced value V. If FROM != NULL, operate in "write
- mode": copy FROM into the pieces comprising V. If FROM == NULL,
- operate in "read mode": fetch the contents of the (lazy) value V by
- composing it from its pieces. If CHECK_OPTIMIZED is true, then no
- reading or writing is done; instead the return value of this
- function is true if any piece is optimized out. When
- CHECK_OPTIMIZED is true, FROM must be nullptr. */
- static bool
- rw_pieced_value (value *v, value *from, bool check_optimized)
- {
- int i;
- LONGEST offset = 0, max_offset;
- gdb_byte *v_contents;
- const gdb_byte *from_contents;
- piece_closure *c
- = (piece_closure *) value_computed_closure (v);
- gdb::byte_vector buffer;
- bool bits_big_endian = type_byte_order (value_type (v)) == BFD_ENDIAN_BIG;
- gdb_assert (!check_optimized || from == nullptr);
- if (from != nullptr)
- {
- from_contents = value_contents (from).data ();
- v_contents = nullptr;
- }
- else
- {
- 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"));
- if (check_optimized)
- v_contents = nullptr;
- else
- v_contents = value_contents_raw (v).data ();
- from_contents = nullptr;
- }
- ULONGEST bits_to_skip = 8 * value_offset (v);
- if (value_bitsize (v))
- {
- bits_to_skip += (8 * value_offset (value_parent (v))
- + value_bitpos (v));
- if (from != nullptr
- && (type_byte_order (value_type (from))
- == BFD_ENDIAN_BIG))
- {
- /* Use the least significant bits of FROM. */
- max_offset = 8 * TYPE_LENGTH (value_type (from));
- offset = max_offset - value_bitsize (v);
- }
- else
- max_offset = value_bitsize (v);
- }
- else
- max_offset = 8 * TYPE_LENGTH (value_type (v));
- /* Advance to the first non-skipped piece. */
- for (i = 0; i < c->pieces.size () && bits_to_skip >= c->pieces[i].size; i++)
- bits_to_skip -= c->pieces[i].size;
- for (; i < c->pieces.size () && offset < max_offset; i++)
- {
- dwarf_expr_piece *p = &c->pieces[i];
- size_t this_size_bits, this_size;
- this_size_bits = p->size - bits_to_skip;
- if (this_size_bits > max_offset - offset)
- this_size_bits = max_offset - offset;
- switch (p->location)
- {
- case DWARF_VALUE_REGISTER:
- {
- frame_info *frame = frame_find_by_id (c->frame_id);
- gdbarch *arch = get_frame_arch (frame);
- int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
- ULONGEST reg_bits = 8 * register_size (arch, gdb_regnum);
- int optim, unavail;
- if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
- && p->offset + p->size < reg_bits)
- {
- /* Big-endian, and we want less than full size. */
- bits_to_skip += reg_bits - (p->offset + p->size);
- }
- else
- bits_to_skip += p->offset;
- this_size = bits_to_bytes (bits_to_skip, this_size_bits);
- buffer.resize (this_size);
- if (from == nullptr)
- {
- /* Read mode. */
- if (!get_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer, &optim, &unavail))
- {
- if (optim)
- {
- if (check_optimized)
- return true;
- mark_value_bits_optimized_out (v, offset,
- this_size_bits);
- }
- if (unavail && !check_optimized)
- mark_value_bits_unavailable (v, offset,
- this_size_bits);
- break;
- }
- if (!check_optimized)
- copy_bitwise (v_contents, offset,
- buffer.data (), bits_to_skip % 8,
- this_size_bits, bits_big_endian);
- }
- else
- {
- /* Write mode. */
- if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
- {
- /* Data is copied non-byte-aligned into the register.
- Need some bits from original register value. */
- get_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer, &optim, &unavail);
- if (optim)
- throw_error (OPTIMIZED_OUT_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.data (), bits_to_skip % 8,
- from_contents, offset,
- this_size_bits, bits_big_endian);
- put_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer);
- }
- }
- break;
- case DWARF_VALUE_MEMORY:
- {
- if (check_optimized)
- break;
- bits_to_skip += p->offset;
- CORE_ADDR start_addr = p->v.mem.addr + bits_to_skip / 8;
- if (bits_to_skip % 8 == 0 && this_size_bits % 8 == 0
- && offset % 8 == 0)
- {
- /* Everything is byte-aligned; no buffer needed. */
- if (from != nullptr)
- write_memory_with_notification (start_addr,
- (from_contents
- + offset / 8),
- this_size_bits / 8);
- else
- read_value_memory (v, offset,
- p->v.mem.in_stack_memory,
- p->v.mem.addr + bits_to_skip / 8,
- v_contents + offset / 8,
- this_size_bits / 8);
- break;
- }
- this_size = bits_to_bytes (bits_to_skip, this_size_bits);
- buffer.resize (this_size);
- if (from == nullptr)
- {
- /* Read mode. */
- read_value_memory (v, offset,
- p->v.mem.in_stack_memory,
- p->v.mem.addr + bits_to_skip / 8,
- buffer.data (), this_size);
- copy_bitwise (v_contents, offset,
- buffer.data (), bits_to_skip % 8,
- this_size_bits, bits_big_endian);
- }
- else
- {
- /* Write mode. */
- if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
- {
- if (this_size <= 8)
- {
- /* Perform a single read for small sizes. */
- read_memory (start_addr, buffer.data (),
- this_size);
- }
- else
- {
- /* Only the first and last bytes can possibly have
- any bits reused. */
- read_memory (start_addr, buffer.data (), 1);
- read_memory (start_addr + this_size - 1,
- &buffer[this_size - 1], 1);
- }
- }
- copy_bitwise (buffer.data (), bits_to_skip % 8,
- from_contents, offset,
- this_size_bits, bits_big_endian);
- write_memory_with_notification (start_addr,
- buffer.data (),
- this_size);
- }
- }
- break;
- case DWARF_VALUE_STACK:
- {
- if (check_optimized)
- break;
- if (from != nullptr)
- {
- mark_value_bits_optimized_out (v, offset, this_size_bits);
- break;
- }
- gdbarch *objfile_gdbarch = c->per_objfile->objfile->arch ();
- ULONGEST stack_value_size_bits
- = 8 * TYPE_LENGTH (value_type (p->v.value));
- /* Use zeroes if piece reaches beyond stack value. */
- if (p->offset + p->size > stack_value_size_bits)
- break;
- /* Piece is anchored at least significant bit end. */
- if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
- bits_to_skip += stack_value_size_bits - p->offset - p->size;
- else
- bits_to_skip += p->offset;
- copy_bitwise (v_contents, offset,
- value_contents_all (p->v.value).data (),
- bits_to_skip,
- this_size_bits, bits_big_endian);
- }
- break;
- case DWARF_VALUE_LITERAL:
- {
- if (check_optimized)
- break;
- if (from != nullptr)
- {
- mark_value_bits_optimized_out (v, offset, this_size_bits);
- break;
- }
- ULONGEST literal_size_bits = 8 * p->v.literal.length;
- size_t n = this_size_bits;
- /* Cut off at the end of the implicit value. */
- bits_to_skip += p->offset;
- if (bits_to_skip >= literal_size_bits)
- break;
- if (n > literal_size_bits - bits_to_skip)
- n = literal_size_bits - bits_to_skip;
- copy_bitwise (v_contents, offset,
- p->v.literal.data, bits_to_skip,
- n, bits_big_endian);
- }
- break;
- case DWARF_VALUE_IMPLICIT_POINTER:
- if (from != nullptr)
- {
- mark_value_bits_optimized_out (v, offset, this_size_bits);
- break;
- }
- /* These bits show up as zeros -- but do not cause the value to
- be considered optimized-out. */
- break;
- case DWARF_VALUE_OPTIMIZED_OUT:
- if (check_optimized)
- return true;
- mark_value_bits_optimized_out (v, offset, this_size_bits);
- break;
- default:
- internal_error (__FILE__, __LINE__, _("invalid location type"));
- }
- offset += this_size_bits;
- bits_to_skip = 0;
- }
- return false;
- }
- static void
- read_pieced_value (value *v)
- {
- rw_pieced_value (v, nullptr, false);
- }
- static void
- write_pieced_value (value *to, value *from)
- {
- rw_pieced_value (to, from, false);
- }
- static bool
- is_optimized_out_pieced_value (value *v)
- {
- return rw_pieced_value (v, nullptr, true);
- }
- /* An implementation of an lval_funcs method to see whether a value is
- a synthetic pointer. */
- static int
- check_pieced_synthetic_pointer (const value *value, LONGEST bit_offset,
- int bit_length)
- {
- piece_closure *c = (piece_closure *) value_computed_closure (value);
- int i;
- bit_offset += 8 * value_offset (value);
- if (value_bitsize (value))
- bit_offset += value_bitpos (value);
- for (i = 0; i < c->pieces.size () && bit_length > 0; i++)
- {
- 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 0;
- }
- return 1;
- }
- /* An implementation of an lval_funcs method to indirect through a
- pointer. This handles the synthetic pointer case when needed. */
- static value *
- indirect_pieced_value (value *value)
- {
- piece_closure *c
- = (piece_closure *) value_computed_closure (value);
- int i;
- dwarf_expr_piece *piece = NULL;
- struct type *type = check_typedef (value_type (value));
- if (type->code () != TYPE_CODE_PTR)
- return NULL;
- int bit_length = 8 * TYPE_LENGTH (type);
- LONGEST bit_offset = 8 * value_offset (value);
- if (value_bitsize (value))
- bit_offset += value_bitpos (value);
- for (i = 0; i < c->pieces.size () && bit_length > 0; i++)
- {
- 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_implicit_pointer"));
- piece = p;
- break;
- }
- gdb_assert (piece != NULL && c->per_cu != nullptr);
- frame_info *frame = get_selected_frame (_("No frame selected."));
- /* This is an offset requested by GDB, such as value subscripts.
- However, due to how synthetic pointers are implemented, this is
- always presented to us as a pointer type. This means we have to
- sign-extend it manually as appropriate. Use raw
- extract_signed_integer directly rather than value_as_address and
- sign extend afterwards on architectures that would need it
- (mostly everywhere except MIPS, which has signed addresses) as
- the later would go through gdbarch_pointer_to_address and thus
- return a CORE_ADDR with high bits set on architectures that
- encode address spaces and other things in CORE_ADDR. */
- bfd_endian byte_order = gdbarch_byte_order (get_frame_arch (frame));
- LONGEST byte_offset
- = extract_signed_integer (value_contents (value), byte_order);
- byte_offset += piece->v.ptr.offset;
- return indirect_synthetic_pointer (piece->v.ptr.die_sect_off,
- byte_offset, c->per_cu,
- c->per_objfile, frame, type);
- }
- /* Implementation of the coerce_ref method of lval_funcs for synthetic C++
- references. */
- static value *
- coerce_pieced_ref (const value *value)
- {
- struct type *type = check_typedef (value_type (value));
- if (value_bits_synthetic_pointer (value, value_embedded_offset (value),
- TARGET_CHAR_BIT * TYPE_LENGTH (type)))
- {
- const piece_closure *closure
- = (piece_closure *) value_computed_closure (value);
- frame_info *frame
- = get_selected_frame (_("No frame selected."));
- /* gdb represents synthetic pointers as pieced values with a single
- piece. */
- gdb_assert (closure != NULL);
- gdb_assert (closure->pieces.size () == 1);
- return indirect_synthetic_pointer
- (closure->pieces[0].v.ptr.die_sect_off,
- closure->pieces[0].v.ptr.offset,
- closure->per_cu, closure->per_objfile, frame, type);
- }
- else
- {
- /* Else: not a synthetic reference; do nothing. */
- return NULL;
- }
- }
- static void *
- copy_pieced_value_closure (const value *v)
- {
- piece_closure *c = (piece_closure *) value_computed_closure (v);
- ++c->refc;
- return c;
- }
- static void
- free_pieced_value_closure (value *v)
- {
- piece_closure *c = (piece_closure *) value_computed_closure (v);
- --c->refc;
- if (c->refc == 0)
- {
- for (dwarf_expr_piece &p : c->pieces)
- if (p.location == DWARF_VALUE_STACK)
- value_decref (p.v.value);
- delete c;
- }
- }
- /* Functions for accessing a variable described by DW_OP_piece. */
- static const struct lval_funcs pieced_value_funcs = {
- read_pieced_value,
- write_pieced_value,
- is_optimized_out_pieced_value,
- indirect_pieced_value,
- coerce_pieced_ref,
- check_pieced_synthetic_pointer,
- copy_pieced_value_closure,
- free_pieced_value_closure
- };
- /* Given context CTX, section offset SECT_OFF, and compilation unit
- data PER_CU, execute the "variable value" operation on the DIE
- found at SECT_OFF. */
- static value *
- sect_variable_value (sect_offset sect_off,
- dwarf2_per_cu_data *per_cu,
- dwarf2_per_objfile *per_objfile)
- {
- const char *var_name = nullptr;
- struct type *die_type
- = dwarf2_fetch_die_type_sect_off (sect_off, per_cu, per_objfile,
- &var_name);
- if (die_type == NULL)
- error (_("Bad DW_OP_GNU_variable_value DIE."));
- /* Note: Things still work when the following test is removed. This
- test and error is here to conform to the proposed specification. */
- if (die_type->code () != TYPE_CODE_INT
- && die_type->code () != TYPE_CODE_ENUM
- && die_type->code () != TYPE_CODE_RANGE
- && die_type->code () != TYPE_CODE_PTR)
- error (_("Type of DW_OP_GNU_variable_value DIE must be an integer or pointer."));
- if (var_name != nullptr)
- {
- value *result = compute_var_value (var_name);
- if (result != nullptr)
- return result;
- }
- struct type *type = lookup_pointer_type (die_type);
- frame_info *frame = get_selected_frame (_("No frame selected."));
- return indirect_synthetic_pointer (sect_off, 0, per_cu, per_objfile, frame,
- type, true);
- }
- /* Return the type used for DWARF operations where the type is
- unspecified in the DWARF spec. Only certain sizes are
- supported. */
- struct type *
- dwarf_expr_context::address_type () const
- {
- gdbarch *arch = this->m_per_objfile->objfile->arch ();
- dwarf_gdbarch_types *types
- = (dwarf_gdbarch_types *) gdbarch_data (arch, dwarf_arch_cookie);
- int ndx;
- if (this->m_addr_size == 2)
- ndx = 0;
- else if (this->m_addr_size == 4)
- ndx = 1;
- else if (this->m_addr_size == 8)
- ndx = 2;
- else
- error (_("Unsupported address size in DWARF expressions: %d bits"),
- 8 * this->m_addr_size);
- if (types->dw_types[ndx] == NULL)
- types->dw_types[ndx]
- = arch_integer_type (arch, 8 * this->m_addr_size,
- 0, "<signed DWARF address type>");
- return types->dw_types[ndx];
- }
- /* Create a new context for the expression evaluator. */
- dwarf_expr_context::dwarf_expr_context (dwarf2_per_objfile *per_objfile,
- int addr_size)
- : m_addr_size (addr_size),
- m_per_objfile (per_objfile)
- {
- }
- /* Push VALUE onto the stack. */
- void
- dwarf_expr_context::push (struct value *value, bool in_stack_memory)
- {
- this->m_stack.emplace_back (value, in_stack_memory);
- }
- /* Push VALUE onto the stack. */
- void
- dwarf_expr_context::push_address (CORE_ADDR value, bool in_stack_memory)
- {
- push (value_from_ulongest (address_type (), value), in_stack_memory);
- }
- /* Pop the top item off of the stack. */
- void
- dwarf_expr_context::pop ()
- {
- if (this->m_stack.empty ())
- error (_("dwarf expression stack underflow"));
- this->m_stack.pop_back ();
- }
- /* Retrieve the N'th item on the stack. */
- struct value *
- dwarf_expr_context::fetch (int n)
- {
- if (this->m_stack.size () <= n)
- error (_("Asked for position %d of stack, "
- "stack only has %zu elements on it."),
- n, this->m_stack.size ());
- return this->m_stack[this->m_stack.size () - (1 + n)].value;
- }
- /* See expr.h. */
- void
- dwarf_expr_context::get_frame_base (const gdb_byte **start,
- size_t * length)
- {
- ensure_have_frame (this->m_frame, "DW_OP_fbreg");
- const block *bl = get_frame_block (this->m_frame, NULL);
- if (bl == NULL)
- error (_("frame address is not available."));
- /* Use block_linkage_function, which returns a real (not inlined)
- function, instead of get_frame_function, which may return an
- inlined function. */
- symbol *framefunc = block_linkage_function (bl);
- /* 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);
- func_get_frame_base_dwarf_block (framefunc,
- get_frame_address_in_block (this->m_frame),
- start, length);
- }
- /* See expr.h. */
- struct type *
- dwarf_expr_context::get_base_type (cu_offset die_cu_off)
- {
- if (this->m_per_cu == nullptr)
- return builtin_type (this->m_per_objfile->objfile->arch ())->builtin_int;
- struct type *result = dwarf2_get_die_type (die_cu_off, this->m_per_cu,
- this->m_per_objfile);
- if (result == nullptr)
- error (_("Could not find type for operation"));
- return result;
- }
- /* See expr.h. */
- void
- dwarf_expr_context::dwarf_call (cu_offset die_cu_off)
- {
- ensure_have_per_cu (this->m_per_cu, "DW_OP_call");
- frame_info *frame = this->m_frame;
- auto get_pc_from_frame = [frame] ()
- {
- ensure_have_frame (frame, "DW_OP_call");
- return get_frame_address_in_block (frame);
- };
- dwarf2_locexpr_baton block
- = dwarf2_fetch_die_loc_cu_off (die_cu_off, this->m_per_cu,
- this->m_per_objfile, get_pc_from_frame);
- /* DW_OP_call_ref is currently not supported. */
- gdb_assert (block.per_cu == this->m_per_cu);
- this->eval (block.data, block.size);
- }
- /* See expr.h. */
- void
- dwarf_expr_context::read_mem (gdb_byte *buf, CORE_ADDR addr,
- size_t length)
- {
- if (length == 0)
- return;
- /* Prefer the passed-in memory, if it exists. */
- if (this->m_addr_info != nullptr)
- {
- CORE_ADDR offset = addr - this->m_addr_info->addr;
- if (offset < this->m_addr_info->valaddr.size ()
- && offset + length <= this->m_addr_info->valaddr.size ())
- {
- memcpy (buf, this->m_addr_info->valaddr.data (), length);
- return;
- }
- }
- read_memory (addr, buf, length);
- }
- /* See expr.h. */
- void
- dwarf_expr_context::push_dwarf_reg_entry_value (call_site_parameter_kind kind,
- call_site_parameter_u kind_u,
- int deref_size)
- {
- ensure_have_per_cu (this->m_per_cu, "DW_OP_entry_value");
- ensure_have_frame (this->m_frame, "DW_OP_entry_value");
- dwarf2_per_cu_data *caller_per_cu;
- dwarf2_per_objfile *caller_per_objfile;
- frame_info *caller_frame = get_prev_frame (this->m_frame);
- call_site_parameter *parameter
- = dwarf_expr_reg_to_entry_parameter (this->m_frame, kind, kind_u,
- &caller_per_cu,
- &caller_per_objfile);
- const gdb_byte *data_src
- = deref_size == -1 ? parameter->value : parameter->data_value;
- size_t size
- = deref_size == -1 ? parameter->value_size : parameter->data_value_size;
- /* DEREF_SIZE size is not verified here. */
- if (data_src == nullptr)
- throw_error (NO_ENTRY_VALUE_ERROR,
- _("Cannot resolve DW_AT_call_data_value"));
- /* We are about to evaluate an expression in the context of the caller
- of the current frame. This evaluation context may be different from
- the current (callee's) context), so temporarily set the caller's context.
- It is possible for the caller to be from a different objfile from the
- callee if the call is made through a function pointer. */
- scoped_restore save_frame = make_scoped_restore (&this->m_frame,
- caller_frame);
- scoped_restore save_per_cu = make_scoped_restore (&this->m_per_cu,
- caller_per_cu);
- scoped_restore save_addr_info = make_scoped_restore (&this->m_addr_info,
- nullptr);
- scoped_restore save_per_objfile = make_scoped_restore (&this->m_per_objfile,
- caller_per_objfile);
- scoped_restore save_addr_size = make_scoped_restore (&this->m_addr_size);
- this->m_addr_size = this->m_per_cu->addr_size ();
- this->eval (data_src, size);
- }
- /* See expr.h. */
- value *
- dwarf_expr_context::fetch_result (struct type *type, struct type *subobj_type,
- LONGEST subobj_offset, bool as_lval)
- {
- value *retval = nullptr;
- gdbarch *arch = this->m_per_objfile->objfile->arch ();
- if (type == nullptr)
- type = address_type ();
- if (subobj_type == nullptr)
- subobj_type = type;
- if (this->m_pieces.size () > 0)
- {
- ULONGEST bit_size = 0;
- for (dwarf_expr_piece &piece : this->m_pieces)
- bit_size += piece.size;
- /* Complain if the expression is larger than the size of the
- outer type. */
- if (bit_size > 8 * TYPE_LENGTH (type))
- invalid_synthetic_pointer ();
- piece_closure *c
- = allocate_piece_closure (this->m_per_cu, this->m_per_objfile,
- std::move (this->m_pieces), this->m_frame);
- retval = allocate_computed_value (subobj_type,
- &pieced_value_funcs, c);
- set_value_offset (retval, subobj_offset);
- }
- else
- {
- /* If AS_LVAL is false, means that the implicit conversion
- from a location description to value is expected. */
- if (!as_lval)
- this->m_location = DWARF_VALUE_STACK;
- switch (this->m_location)
- {
- case DWARF_VALUE_REGISTER:
- {
- gdbarch *f_arch = get_frame_arch (this->m_frame);
- int dwarf_regnum
- = longest_to_int (value_as_long (this->fetch (0)));
- int gdb_regnum = dwarf_reg_to_regnum_or_error (f_arch,
- dwarf_regnum);
- if (subobj_offset != 0)
- error (_("cannot use offset on synthetic pointer to register"));
- gdb_assert (this->m_frame != NULL);
- retval = value_from_register (subobj_type, gdb_regnum,
- this->m_frame);
- if (value_optimized_out (retval))
- {
- /* This means the register has undefined value / was
- not saved. As we're computing the location of some
- variable etc. in the program, not a value for
- inspecting a register ($pc, $sp, etc.), return a
- generic optimized out value instead, so that we show
- <optimized out> instead of <not saved>. */
- value *tmp = allocate_value (subobj_type);
- value_contents_copy (tmp, 0, retval, 0,
- TYPE_LENGTH (subobj_type));
- retval = tmp;
- }
- }
- break;
- case DWARF_VALUE_MEMORY:
- {
- struct type *ptr_type;
- CORE_ADDR address = this->fetch_address (0);
- bool in_stack_memory = this->fetch_in_stack_memory (0);
- /* DW_OP_deref_size (and possibly other operations too) may
- create a pointer instead of an address. Ideally, the
- pointer to address conversion would be performed as part
- of those operations, but the type of the object to
- which the address refers is not known at the time of
- the operation. Therefore, we do the conversion here
- since the type is readily available. */
- switch (subobj_type->code ())
- {
- case TYPE_CODE_FUNC:
- case TYPE_CODE_METHOD:
- ptr_type = builtin_type (arch)->builtin_func_ptr;
- break;
- default:
- ptr_type = builtin_type (arch)->builtin_data_ptr;
- break;
- }
- address = value_as_address (value_from_pointer (ptr_type, address));
- retval = value_at_lazy (subobj_type,
- address + subobj_offset);
- if (in_stack_memory)
- set_value_stack (retval, 1);
- }
- break;
- case DWARF_VALUE_STACK:
- {
- value *val = this->fetch (0);
- size_t n = TYPE_LENGTH (value_type (val));
- size_t len = TYPE_LENGTH (subobj_type);
- size_t max = TYPE_LENGTH (type);
- if (subobj_offset + len > max)
- invalid_synthetic_pointer ();
- retval = allocate_value (subobj_type);
- /* The given offset is relative to the actual object. */
- if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG)
- subobj_offset += n - max;
- copy (value_contents_all (val).slice (subobj_offset, len),
- value_contents_raw (retval));
- }
- break;
- case DWARF_VALUE_LITERAL:
- {
- size_t n = TYPE_LENGTH (subobj_type);
- if (subobj_offset + n > this->m_len)
- invalid_synthetic_pointer ();
- retval = allocate_value (subobj_type);
- bfd_byte *contents = value_contents_raw (retval).data ();
- memcpy (contents, this->m_data + subobj_offset, n);
- }
- break;
- case DWARF_VALUE_OPTIMIZED_OUT:
- retval = allocate_optimized_out_value (subobj_type);
- 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, this->m_initialized);
- return retval;
- }
- /* See expr.h. */
- value *
- dwarf_expr_context::evaluate (const gdb_byte *addr, size_t len, bool as_lval,
- dwarf2_per_cu_data *per_cu, frame_info *frame,
- const struct property_addr_info *addr_info,
- struct type *type, struct type *subobj_type,
- LONGEST subobj_offset)
- {
- this->m_per_cu = per_cu;
- this->m_frame = frame;
- this->m_addr_info = addr_info;
- eval (addr, len);
- return fetch_result (type, subobj_type, subobj_offset, as_lval);
- }
- /* Require that TYPE be an integral type; throw an exception if not. */
- static void
- dwarf_require_integral (struct type *type)
- {
- if (type->code () != TYPE_CODE_INT
- && type->code () != TYPE_CODE_CHAR
- && type->code () != TYPE_CODE_BOOL)
- error (_("integral type expected in DWARF expression"));
- }
- /* Return the unsigned form of TYPE. TYPE is necessarily an integral
- type. */
- static struct type *
- get_unsigned_type (struct gdbarch *gdbarch, struct type *type)
- {
- switch (TYPE_LENGTH (type))
- {
- case 1:
- return builtin_type (gdbarch)->builtin_uint8;
- case 2:
- return builtin_type (gdbarch)->builtin_uint16;
- case 4:
- return builtin_type (gdbarch)->builtin_uint32;
- case 8:
- return builtin_type (gdbarch)->builtin_uint64;
- default:
- error (_("no unsigned variant found for type, while evaluating "
- "DWARF expression"));
- }
- }
- /* Return the signed form of TYPE. TYPE is necessarily an integral
- type. */
- static struct type *
- get_signed_type (struct gdbarch *gdbarch, struct type *type)
- {
- switch (TYPE_LENGTH (type))
- {
- case 1:
- return builtin_type (gdbarch)->builtin_int8;
- case 2:
- return builtin_type (gdbarch)->builtin_int16;
- case 4:
- return builtin_type (gdbarch)->builtin_int32;
- case 8:
- return builtin_type (gdbarch)->builtin_int64;
- default:
- error (_("no signed variant found for type, while evaluating "
- "DWARF expression"));
- }
- }
- /* Retrieve the N'th item on the stack, converted to an address. */
- CORE_ADDR
- dwarf_expr_context::fetch_address (int n)
- {
- gdbarch *arch = this->m_per_objfile->objfile->arch ();
- value *result_val = fetch (n);
- bfd_endian byte_order = gdbarch_byte_order (arch);
- ULONGEST result;
- dwarf_require_integral (value_type (result_val));
- result = extract_unsigned_integer (value_contents (result_val), byte_order);
- /* For most architectures, calling extract_unsigned_integer() alone
- is sufficient for extracting an address. However, some
- architectures (e.g. MIPS) use signed addresses and using
- extract_unsigned_integer() will not produce a correct
- result. Make sure we invoke gdbarch_integer_to_address()
- for those architectures which require it. */
- if (gdbarch_integer_to_address_p (arch))
- {
- gdb_byte *buf = (gdb_byte *) alloca (this->m_addr_size);
- type *int_type = get_unsigned_type (arch,
- value_type (result_val));
- store_unsigned_integer (buf, this->m_addr_size, byte_order, result);
- return gdbarch_integer_to_address (arch, int_type, buf);
- }
- return (CORE_ADDR) result;
- }
- /* Retrieve the in_stack_memory flag of the N'th item on the stack. */
- bool
- dwarf_expr_context::fetch_in_stack_memory (int n)
- {
- if (this->m_stack.size () <= n)
- error (_("Asked for position %d of stack, "
- "stack only has %zu elements on it."),
- n, this->m_stack.size ());
- return this->m_stack[this->m_stack.size () - (1 + n)].in_stack_memory;
- }
- /* Return true if the expression stack is empty. */
- bool
- dwarf_expr_context::stack_empty_p () const
- {
- return m_stack.empty ();
- }
- /* Add a new piece to the dwarf_expr_context's piece list. */
- void
- dwarf_expr_context::add_piece (ULONGEST size, ULONGEST offset)
- {
- this->m_pieces.emplace_back ();
- dwarf_expr_piece &p = this->m_pieces.back ();
- p.location = this->m_location;
- p.size = size;
- p.offset = offset;
- if (p.location == DWARF_VALUE_LITERAL)
- {
- p.v.literal.data = this->m_data;
- p.v.literal.length = this->m_len;
- }
- else if (stack_empty_p ())
- {
- p.location = DWARF_VALUE_OPTIMIZED_OUT;
- /* Also reset the context's location, for our callers. This is
- a somewhat strange approach, but this lets us avoid setting
- the location to DWARF_VALUE_MEMORY in all the individual
- cases in the evaluator. */
- this->m_location = DWARF_VALUE_OPTIMIZED_OUT;
- }
- else if (p.location == DWARF_VALUE_MEMORY)
- {
- p.v.mem.addr = fetch_address (0);
- p.v.mem.in_stack_memory = fetch_in_stack_memory (0);
- }
- else if (p.location == DWARF_VALUE_IMPLICIT_POINTER)
- {
- p.v.ptr.die_sect_off = (sect_offset) this->m_len;
- p.v.ptr.offset = value_as_long (fetch (0));
- }
- else if (p.location == DWARF_VALUE_REGISTER)
- p.v.regno = value_as_long (fetch (0));
- else
- {
- p.v.value = fetch (0);
- }
- }
- /* Evaluate the expression at ADDR (LEN bytes long). */
- void
- dwarf_expr_context::eval (const gdb_byte *addr, size_t len)
- {
- int old_recursion_depth = this->m_recursion_depth;
- execute_stack_op (addr, addr + len);
- /* RECURSION_DEPTH becomes invalid if an exception was thrown here. */
- gdb_assert (this->m_recursion_depth == old_recursion_depth);
- }
- /* Helper to read a uleb128 value or throw an error. */
- const gdb_byte *
- safe_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end,
- uint64_t *r)
- {
- buf = gdb_read_uleb128 (buf, buf_end, r);
- if (buf == NULL)
- error (_("DWARF expression error: ran off end of buffer reading uleb128 value"));
- return buf;
- }
- /* Helper to read a sleb128 value or throw an error. */
- const gdb_byte *
- safe_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end,
- int64_t *r)
- {
- buf = gdb_read_sleb128 (buf, buf_end, r);
- if (buf == NULL)
- error (_("DWARF expression error: ran off end of buffer reading sleb128 value"));
- return buf;
- }
- const gdb_byte *
- safe_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end)
- {
- buf = gdb_skip_leb128 (buf, buf_end);
- if (buf == NULL)
- error (_("DWARF expression error: ran off end of buffer reading leb128 value"));
- return buf;
- }
- /* Check that the current operator is either at the end of an
- expression, or that it is followed by a composition operator or by
- DW_OP_GNU_uninit (which should terminate the expression). */
- void
- dwarf_expr_require_composition (const gdb_byte *op_ptr, const gdb_byte *op_end,
- const char *op_name)
- {
- if (op_ptr != op_end && *op_ptr != DW_OP_piece && *op_ptr != DW_OP_bit_piece
- && *op_ptr != DW_OP_GNU_uninit)
- error (_("DWARF-2 expression error: `%s' operations must be "
- "used either alone or in conjunction with DW_OP_piece "
- "or DW_OP_bit_piece."),
- op_name);
- }
- /* Return true iff the types T1 and T2 are "the same". This only does
- checks that might reasonably be needed to compare DWARF base
- types. */
- static int
- base_types_equal_p (struct type *t1, struct type *t2)
- {
- if (t1->code () != t2->code ())
- return 0;
- if (t1->is_unsigned () != t2->is_unsigned ())
- return 0;
- return TYPE_LENGTH (t1) == TYPE_LENGTH (t2);
- }
- /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_reg* return the
- DWARF register number. Otherwise return -1. */
- int
- dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end)
- {
- uint64_t dwarf_reg;
- if (buf_end <= buf)
- return -1;
- if (*buf >= DW_OP_reg0 && *buf <= DW_OP_reg31)
- {
- if (buf_end - buf != 1)
- return -1;
- return *buf - DW_OP_reg0;
- }
- if (*buf == DW_OP_regval_type || *buf == DW_OP_GNU_regval_type)
- {
- buf++;
- buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
- if (buf == NULL)
- return -1;
- buf = gdb_skip_leb128 (buf, buf_end);
- if (buf == NULL)
- return -1;
- }
- else if (*buf == DW_OP_regx)
- {
- buf++;
- buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
- if (buf == NULL)
- return -1;
- }
- else
- return -1;
- if (buf != buf_end || (int) dwarf_reg != dwarf_reg)
- return -1;
- return dwarf_reg;
- }
- /* If <BUF..BUF_END] contains DW_FORM_block* with just DW_OP_breg*(0) and
- DW_OP_deref* return the DWARF register number. Otherwise return -1.
- DEREF_SIZE_RETURN contains -1 for DW_OP_deref; otherwise it contains the
- size from DW_OP_deref_size. */
- int
- dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, const gdb_byte *buf_end,
- CORE_ADDR *deref_size_return)
- {
- uint64_t dwarf_reg;
- int64_t offset;
- if (buf_end <= buf)
- return -1;
- if (*buf >= DW_OP_breg0 && *buf <= DW_OP_breg31)
- {
- dwarf_reg = *buf - DW_OP_breg0;
- buf++;
- if (buf >= buf_end)
- return -1;
- }
- else if (*buf == DW_OP_bregx)
- {
- buf++;
- buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
- if (buf == NULL)
- return -1;
- if ((int) dwarf_reg != dwarf_reg)
- return -1;
- }
- else
- return -1;
- buf = gdb_read_sleb128 (buf, buf_end, &offset);
- if (buf == NULL)
- return -1;
- if (offset != 0)
- return -1;
- if (*buf == DW_OP_deref)
- {
- buf++;
- *deref_size_return = -1;
- }
- else if (*buf == DW_OP_deref_size)
- {
- buf++;
- if (buf >= buf_end)
- return -1;
- *deref_size_return = *buf++;
- }
- else
- return -1;
- if (buf != buf_end)
- return -1;
- return dwarf_reg;
- }
- /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_fbreg(X) fill
- in FB_OFFSET_RETURN with the X offset and return 1. Otherwise return 0. */
- int
- dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end,
- CORE_ADDR *fb_offset_return)
- {
- int64_t fb_offset;
- if (buf_end <= buf)
- return 0;
- if (*buf != DW_OP_fbreg)
- return 0;
- buf++;
- buf = gdb_read_sleb128 (buf, buf_end, &fb_offset);
- if (buf == NULL)
- return 0;
- *fb_offset_return = fb_offset;
- if (buf != buf_end || fb_offset != (LONGEST) *fb_offset_return)
- return 0;
- return 1;
- }
- /* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_bregSP(X) fill
- in SP_OFFSET_RETURN with the X offset and return 1. Otherwise return 0.
- The matched SP register number depends on GDBARCH. */
- int
- dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf,
- const gdb_byte *buf_end, CORE_ADDR *sp_offset_return)
- {
- uint64_t dwarf_reg;
- int64_t sp_offset;
- if (buf_end <= buf)
- return 0;
- if (*buf >= DW_OP_breg0 && *buf <= DW_OP_breg31)
- {
- dwarf_reg = *buf - DW_OP_breg0;
- buf++;
- }
- else
- {
- if (*buf != DW_OP_bregx)
- return 0;
- buf++;
- buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
- if (buf == NULL)
- return 0;
- }
- if (dwarf_reg_to_regnum (gdbarch, dwarf_reg)
- != gdbarch_sp_regnum (gdbarch))
- return 0;
- buf = gdb_read_sleb128 (buf, buf_end, &sp_offset);
- if (buf == NULL)
- return 0;
- *sp_offset_return = sp_offset;
- if (buf != buf_end || sp_offset != (LONGEST) *sp_offset_return)
- return 0;
- return 1;
- }
- /* The engine for the expression evaluator. Using the context in this
- object, evaluate the expression between OP_PTR and OP_END. */
- void
- dwarf_expr_context::execute_stack_op (const gdb_byte *op_ptr,
- const gdb_byte *op_end)
- {
- gdbarch *arch = this->m_per_objfile->objfile->arch ();
- bfd_endian byte_order = gdbarch_byte_order (arch);
- /* Old-style "untyped" DWARF values need special treatment in a
- couple of places, specifically DW_OP_mod and DW_OP_shr. We need
- a special type for these values so we can distinguish them from
- values that have an explicit type, because explicitly-typed
- values do not need special treatment. This special type must be
- different (in the `==' sense) from any base type coming from the
- CU. */
- type *address_type = this->address_type ();
- this->m_location = DWARF_VALUE_MEMORY;
- this->m_initialized = 1; /* Default is initialized. */
- if (this->m_recursion_depth > this->m_max_recursion_depth)
- error (_("DWARF-2 expression error: Loop detected (%d)."),
- this->m_recursion_depth);
- this->m_recursion_depth++;
- while (op_ptr < op_end)
- {
- dwarf_location_atom op = (dwarf_location_atom) *op_ptr++;
- ULONGEST result;
- /* Assume the value is not in stack memory.
- Code that knows otherwise sets this to true.
- Some arithmetic on stack addresses can probably be assumed to still
- be a stack address, but we skip this complication for now.
- This is just an optimization, so it's always ok to punt
- and leave this as false. */
- bool in_stack_memory = false;
- uint64_t uoffset, reg;
- int64_t offset;
- value *result_val = NULL;
- /* The DWARF expression might have a bug causing an infinite
- loop. In that case, quitting is the only way out. */
- QUIT;
- 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:
- result = op - DW_OP_lit0;
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_addr:
- result = extract_unsigned_integer (op_ptr,
- this->m_addr_size, byte_order);
- op_ptr += this->m_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)
- result += this->m_per_objfile->objfile->text_section_offset ();
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_addrx:
- case DW_OP_GNU_addr_index:
- ensure_have_per_cu (this->m_per_cu, "DW_OP_addrx");
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- result = dwarf2_read_addr_index (this->m_per_cu, this->m_per_objfile,
- uoffset);
- result += this->m_per_objfile->objfile->text_section_offset ();
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_GNU_const_index:
- ensure_have_per_cu (this->m_per_cu, "DW_OP_GNU_const_index");
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- result = dwarf2_read_addr_index (this->m_per_cu, this->m_per_objfile,
- uoffset);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_const1u:
- result = extract_unsigned_integer (op_ptr, 1, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 1;
- break;
- case DW_OP_const1s:
- result = extract_signed_integer (op_ptr, 1, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 1;
- break;
- case DW_OP_const2u:
- result = extract_unsigned_integer (op_ptr, 2, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 2;
- break;
- case DW_OP_const2s:
- result = extract_signed_integer (op_ptr, 2, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 2;
- break;
- case DW_OP_const4u:
- result = extract_unsigned_integer (op_ptr, 4, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 4;
- break;
- case DW_OP_const4s:
- result = extract_signed_integer (op_ptr, 4, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 4;
- break;
- case DW_OP_const8u:
- result = extract_unsigned_integer (op_ptr, 8, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 8;
- break;
- case DW_OP_const8s:
- result = extract_signed_integer (op_ptr, 8, byte_order);
- result_val = value_from_ulongest (address_type, result);
- op_ptr += 8;
- break;
- case DW_OP_constu:
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- result = uoffset;
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_consts:
- op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
- result = offset;
- result_val = value_from_ulongest (address_type, result);
- break;
- /* The DW_OP_reg operations are required to occur alone in
- location expressions. */
- 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_reg");
- result = op - DW_OP_reg0;
- result_val = value_from_ulongest (address_type, result);
- this->m_location = DWARF_VALUE_REGISTER;
- break;
- case DW_OP_regx:
- op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
- dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
- result = reg;
- result_val = value_from_ulongest (address_type, result);
- this->m_location = DWARF_VALUE_REGISTER;
- break;
- case DW_OP_implicit_value:
- {
- uint64_t len;
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
- if (op_ptr + len > op_end)
- error (_("DW_OP_implicit_value: too few bytes available."));
- this->m_len = len;
- this->m_data = op_ptr;
- this->m_location = DWARF_VALUE_LITERAL;
- op_ptr += len;
- dwarf_expr_require_composition (op_ptr, op_end,
- "DW_OP_implicit_value");
- }
- goto no_push;
- case DW_OP_stack_value:
- this->m_location = DWARF_VALUE_STACK;
- dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
- goto no_push;
- case DW_OP_implicit_pointer:
- case DW_OP_GNU_implicit_pointer:
- {
- int64_t len;
- ensure_have_per_cu (this->m_per_cu, "DW_OP_implicit_pointer");
- int ref_addr_size = this->m_per_cu->ref_addr_size ();
- /* The referred-to DIE of sect_offset kind. */
- this->m_len = extract_unsigned_integer (op_ptr, ref_addr_size,
- byte_order);
- op_ptr += ref_addr_size;
- /* The byte offset into the data. */
- op_ptr = safe_read_sleb128 (op_ptr, op_end, &len);
- result = (ULONGEST) len;
- result_val = value_from_ulongest (address_type, result);
- this->m_location = DWARF_VALUE_IMPLICIT_POINTER;
- dwarf_expr_require_composition (op_ptr, op_end,
- "DW_OP_implicit_pointer");
- }
- 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 = safe_read_sleb128 (op_ptr, op_end, &offset);
- ensure_have_frame (this->m_frame, "DW_OP_breg");
- result = read_addr_from_reg (this->m_frame, op - DW_OP_breg0);
- result += offset;
- result_val = value_from_ulongest (address_type, result);
- }
- break;
- case DW_OP_bregx:
- {
- op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
- op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
- ensure_have_frame (this->m_frame, "DW_OP_bregx");
- result = read_addr_from_reg (this->m_frame, reg);
- result += offset;
- result_val = value_from_ulongest (address_type, result);
- }
- break;
- case DW_OP_fbreg:
- {
- const gdb_byte *datastart;
- size_t datalen;
- op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
- /* Rather than create a whole new context, we simply
- backup the current stack locally and install a new empty stack,
- then reset it afterwards, effectively erasing whatever the
- recursive call put there. */
- std::vector<dwarf_stack_value> saved_stack = std::move (this->m_stack);
- this->m_stack.clear ();
- /* FIXME: cagney/2003-03-26: This code should be using
- get_frame_base_address(), and then implement a dwarf2
- specific this_base method. */
- this->get_frame_base (&datastart, &datalen);
- eval (datastart, datalen);
- if (this->m_location == DWARF_VALUE_MEMORY)
- result = fetch_address (0);
- else if (this->m_location == DWARF_VALUE_REGISTER)
- result
- = read_addr_from_reg (this->m_frame, value_as_long (fetch (0)));
- else
- error (_("Not implemented: computing frame "
- "base using explicit value operator"));
- result = result + offset;
- result_val = value_from_ulongest (address_type, result);
- in_stack_memory = true;
- /* Restore the content of the original stack. */
- this->m_stack = std::move (saved_stack);
- this->m_location = DWARF_VALUE_MEMORY;
- }
- break;
- case DW_OP_dup:
- result_val = fetch (0);
- in_stack_memory = fetch_in_stack_memory (0);
- break;
- case DW_OP_drop:
- pop ();
- goto no_push;
- case DW_OP_pick:
- offset = *op_ptr++;
- result_val = fetch (offset);
- in_stack_memory = fetch_in_stack_memory (offset);
- break;
-
- case DW_OP_swap:
- {
- if (this->m_stack.size () < 2)
- error (_("Not enough elements for "
- "DW_OP_swap. Need 2, have %zu."),
- this->m_stack.size ());
- dwarf_stack_value &t1 = this->m_stack[this->m_stack.size () - 1];
- dwarf_stack_value &t2 = this->m_stack[this->m_stack.size () - 2];
- std::swap (t1, t2);
- goto no_push;
- }
- case DW_OP_over:
- result_val = fetch (1);
- in_stack_memory = fetch_in_stack_memory (1);
- break;
- case DW_OP_rot:
- {
- if (this->m_stack.size () < 3)
- error (_("Not enough elements for "
- "DW_OP_rot. Need 3, have %zu."),
- this->m_stack.size ());
- dwarf_stack_value temp = this->m_stack[this->m_stack.size () - 1];
- this->m_stack[this->m_stack.size () - 1]
- = this->m_stack[this->m_stack.size () - 2];
- this->m_stack[this->m_stack.size () - 2]
- = this->m_stack[this->m_stack.size () - 3];
- this->m_stack[this->m_stack.size () - 3] = temp;
- goto no_push;
- }
- case DW_OP_deref:
- case DW_OP_deref_size:
- case DW_OP_deref_type:
- case DW_OP_GNU_deref_type:
- {
- int addr_size = (op == DW_OP_deref ? this->m_addr_size : *op_ptr++);
- gdb_byte *buf = (gdb_byte *) alloca (addr_size);
- CORE_ADDR addr = fetch_address (0);
- struct type *type;
- pop ();
- if (op == DW_OP_deref_type || op == DW_OP_GNU_deref_type)
- {
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- cu_offset type_die_cu_off = (cu_offset) uoffset;
- type = get_base_type (type_die_cu_off);
- }
- else
- type = address_type;
- this->read_mem (buf, addr, addr_size);
- /* If the size of the object read from memory is different
- from the type length, we need to zero-extend it. */
- if (TYPE_LENGTH (type) != addr_size)
- {
- ULONGEST datum =
- extract_unsigned_integer (buf, addr_size, byte_order);
- buf = (gdb_byte *) alloca (TYPE_LENGTH (type));
- store_unsigned_integer (buf, TYPE_LENGTH (type),
- byte_order, datum);
- }
- result_val = value_from_contents_and_address (type, buf, addr);
- break;
- }
- case DW_OP_abs:
- case DW_OP_neg:
- case DW_OP_not:
- case DW_OP_plus_uconst:
- {
- /* Unary operations. */
- result_val = fetch (0);
- pop ();
- switch (op)
- {
- case DW_OP_abs:
- if (value_less (result_val,
- value_zero (value_type (result_val), not_lval)))
- result_val = value_neg (result_val);
- break;
- case DW_OP_neg:
- result_val = value_neg (result_val);
- break;
- case DW_OP_not:
- dwarf_require_integral (value_type (result_val));
- result_val = value_complement (result_val);
- break;
- case DW_OP_plus_uconst:
- dwarf_require_integral (value_type (result_val));
- result = value_as_long (result_val);
- op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
- result += reg;
- result_val = value_from_ulongest (address_type, result);
- break;
- }
- }
- break;
- case DW_OP_and:
- case DW_OP_div:
- case DW_OP_minus:
- case DW_OP_mod:
- case DW_OP_mul:
- case DW_OP_or:
- case DW_OP_plus:
- case DW_OP_shl:
- case DW_OP_shr:
- case DW_OP_shra:
- case DW_OP_xor:
- case DW_OP_le:
- case DW_OP_ge:
- case DW_OP_eq:
- case DW_OP_lt:
- case DW_OP_gt:
- case DW_OP_ne:
- {
- /* Binary operations. */
- struct value *first, *second;
- second = fetch (0);
- pop ();
- first = fetch (0);
- pop ();
- if (! base_types_equal_p (value_type (first), value_type (second)))
- error (_("Incompatible types on DWARF stack"));
- switch (op)
- {
- case DW_OP_and:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- result_val = value_binop (first, second, BINOP_BITWISE_AND);
- break;
- case DW_OP_div:
- result_val = value_binop (first, second, BINOP_DIV);
- break;
- case DW_OP_minus:
- result_val = value_binop (first, second, BINOP_SUB);
- break;
- case DW_OP_mod:
- {
- int cast_back = 0;
- struct type *orig_type = value_type (first);
- /* We have to special-case "old-style" untyped values
- -- these must have mod computed using unsigned
- math. */
- if (orig_type == address_type)
- {
- struct type *utype = get_unsigned_type (arch, orig_type);
- cast_back = 1;
- first = value_cast (utype, first);
- second = value_cast (utype, second);
- }
- /* Note that value_binop doesn't handle float or
- decimal float here. This seems unimportant. */
- result_val = value_binop (first, second, BINOP_MOD);
- if (cast_back)
- result_val = value_cast (orig_type, result_val);
- }
- break;
- case DW_OP_mul:
- result_val = value_binop (first, second, BINOP_MUL);
- break;
- case DW_OP_or:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- result_val = value_binop (first, second, BINOP_BITWISE_IOR);
- break;
- case DW_OP_plus:
- result_val = value_binop (first, second, BINOP_ADD);
- break;
- case DW_OP_shl:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- result_val = value_binop (first, second, BINOP_LSH);
- break;
- case DW_OP_shr:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- if (!value_type (first)->is_unsigned ())
- {
- struct type *utype
- = get_unsigned_type (arch, value_type (first));
- first = value_cast (utype, first);
- }
- result_val = value_binop (first, second, BINOP_RSH);
- /* Make sure we wind up with the same type we started
- with. */
- if (value_type (result_val) != value_type (second))
- result_val = value_cast (value_type (second), result_val);
- break;
- case DW_OP_shra:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- if (value_type (first)->is_unsigned ())
- {
- struct type *stype
- = get_signed_type (arch, value_type (first));
- first = value_cast (stype, first);
- }
- result_val = value_binop (first, second, BINOP_RSH);
- /* Make sure we wind up with the same type we started
- with. */
- if (value_type (result_val) != value_type (second))
- result_val = value_cast (value_type (second), result_val);
- break;
- case DW_OP_xor:
- dwarf_require_integral (value_type (first));
- dwarf_require_integral (value_type (second));
- result_val = value_binop (first, second, BINOP_BITWISE_XOR);
- break;
- case DW_OP_le:
- /* A <= B is !(B < A). */
- result = ! value_less (second, first);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_ge:
- /* A >= B is !(A < B). */
- result = ! value_less (first, second);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_eq:
- result = value_equal (first, second);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_lt:
- result = value_less (first, second);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_gt:
- /* A > B is B < A. */
- result = value_less (second, first);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_ne:
- result = ! value_equal (first, second);
- result_val = value_from_ulongest (address_type, result);
- break;
- default:
- internal_error (__FILE__, __LINE__,
- _("Can't be reached."));
- }
- }
- break;
- case DW_OP_call_frame_cfa:
- ensure_have_frame (this->m_frame, "DW_OP_call_frame_cfa");
- result = dwarf2_frame_cfa (this->m_frame);
- result_val = value_from_ulongest (address_type, result);
- in_stack_memory = true;
- break;
- case DW_OP_GNU_push_tls_address:
- case DW_OP_form_tls_address:
- /* Variable is at a constant offset in the thread-local
- storage block into the objfile for the current thread and
- the dynamic linker module containing this expression. Here
- we return returns the offset from that base. The top of the
- stack has the offset from the beginning of the thread
- control block at which the variable is located. Nothing
- should follow this operator, so the top of stack would be
- returned. */
- result = value_as_long (fetch (0));
- pop ();
- result = target_translate_tls_address (this->m_per_objfile->objfile,
- result);
- result_val = value_from_ulongest (address_type, result);
- break;
- case DW_OP_skip:
- offset = extract_signed_integer (op_ptr, 2, byte_order);
- op_ptr += 2;
- op_ptr += offset;
- goto no_push;
- case DW_OP_bra:
- {
- struct value *val;
- offset = extract_signed_integer (op_ptr, 2, byte_order);
- op_ptr += 2;
- val = fetch (0);
- dwarf_require_integral (value_type (val));
- if (value_as_long (val) != 0)
- op_ptr += offset;
- pop ();
- }
- goto no_push;
- case DW_OP_nop:
- goto no_push;
- case DW_OP_piece:
- {
- uint64_t size;
- /* Record the piece. */
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
- add_piece (8 * size, 0);
- /* Pop off the address/regnum, and reset the location
- type. */
- if (this->m_location != DWARF_VALUE_LITERAL
- && this->m_location != DWARF_VALUE_OPTIMIZED_OUT)
- pop ();
- this->m_location = DWARF_VALUE_MEMORY;
- }
- goto no_push;
- case DW_OP_bit_piece:
- {
- uint64_t size, uleb_offset;
- /* Record the piece. */
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &size);
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uleb_offset);
- add_piece (size, uleb_offset);
- /* Pop off the address/regnum, and reset the location
- type. */
- if (this->m_location != DWARF_VALUE_LITERAL
- && this->m_location != DWARF_VALUE_OPTIMIZED_OUT)
- pop ();
- this->m_location = DWARF_VALUE_MEMORY;
- }
- goto no_push;
- case DW_OP_GNU_uninit:
- if (op_ptr != op_end)
- error (_("DWARF-2 expression error: DW_OP_GNU_uninit must always "
- "be the very last op."));
- this->m_initialized = 0;
- goto no_push;
- case DW_OP_call2:
- {
- cu_offset cu_off
- = (cu_offset) extract_unsigned_integer (op_ptr, 2, byte_order);
- op_ptr += 2;
- this->dwarf_call (cu_off);
- }
- goto no_push;
- case DW_OP_call4:
- {
- cu_offset cu_off
- = (cu_offset) extract_unsigned_integer (op_ptr, 4, byte_order);
- op_ptr += 4;
- this->dwarf_call (cu_off);
- }
- goto no_push;
- case DW_OP_GNU_variable_value:
- {
- ensure_have_per_cu (this->m_per_cu, "DW_OP_GNU_variable_value");
- int ref_addr_size = this->m_per_cu->ref_addr_size ();
- sect_offset sect_off
- = (sect_offset) extract_unsigned_integer (op_ptr,
- ref_addr_size,
- byte_order);
- op_ptr += ref_addr_size;
- result_val = sect_variable_value (sect_off, this->m_per_cu,
- this->m_per_objfile);
- result_val = value_cast (address_type, result_val);
- }
- break;
-
- case DW_OP_entry_value:
- case DW_OP_GNU_entry_value:
- {
- uint64_t len;
- CORE_ADDR deref_size;
- union call_site_parameter_u kind_u;
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
- if (op_ptr + len > op_end)
- error (_("DW_OP_entry_value: too few bytes available."));
- kind_u.dwarf_reg = dwarf_block_to_dwarf_reg (op_ptr, op_ptr + len);
- if (kind_u.dwarf_reg != -1)
- {
- op_ptr += len;
- this->push_dwarf_reg_entry_value (CALL_SITE_PARAMETER_DWARF_REG,
- kind_u,
- -1 /* deref_size */);
- goto no_push;
- }
- kind_u.dwarf_reg = dwarf_block_to_dwarf_reg_deref (op_ptr,
- op_ptr + len,
- &deref_size);
- if (kind_u.dwarf_reg != -1)
- {
- if (deref_size == -1)
- deref_size = this->m_addr_size;
- op_ptr += len;
- this->push_dwarf_reg_entry_value (CALL_SITE_PARAMETER_DWARF_REG,
- kind_u, deref_size);
- goto no_push;
- }
- error (_("DWARF-2 expression error: DW_OP_entry_value is "
- "supported only for single DW_OP_reg* "
- "or for DW_OP_breg*(0)+DW_OP_deref*"));
- }
- case DW_OP_GNU_parameter_ref:
- {
- union call_site_parameter_u kind_u;
- kind_u.param_cu_off
- = (cu_offset) extract_unsigned_integer (op_ptr, 4, byte_order);
- op_ptr += 4;
- this->push_dwarf_reg_entry_value (CALL_SITE_PARAMETER_PARAM_OFFSET,
- kind_u,
- -1 /* deref_size */);
- }
- goto no_push;
- case DW_OP_const_type:
- case DW_OP_GNU_const_type:
- {
- int n;
- const gdb_byte *data;
- struct type *type;
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- cu_offset type_die_cu_off = (cu_offset) uoffset;
- n = *op_ptr++;
- data = op_ptr;
- op_ptr += n;
- type = get_base_type (type_die_cu_off);
- if (TYPE_LENGTH (type) != n)
- error (_("DW_OP_const_type has different sizes for type and data"));
- result_val = value_from_contents (type, data);
- }
- break;
- case DW_OP_regval_type:
- case DW_OP_GNU_regval_type:
- {
- op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- cu_offset type_die_cu_off = (cu_offset) uoffset;
- ensure_have_frame (this->m_frame, "DW_OP_regval_type");
- struct type *type = get_base_type (type_die_cu_off);
- int regnum
- = dwarf_reg_to_regnum_or_error (get_frame_arch (this->m_frame),
- reg);
- result_val = value_from_register (type, regnum, this->m_frame);
- }
- break;
- case DW_OP_convert:
- case DW_OP_GNU_convert:
- case DW_OP_reinterpret:
- case DW_OP_GNU_reinterpret:
- {
- struct type *type;
- op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
- cu_offset type_die_cu_off = (cu_offset) uoffset;
- if (to_underlying (type_die_cu_off) == 0)
- type = address_type;
- else
- type = get_base_type (type_die_cu_off);
- result_val = fetch (0);
- pop ();
- if (op == DW_OP_convert || op == DW_OP_GNU_convert)
- result_val = value_cast (type, result_val);
- else if (type == value_type (result_val))
- {
- /* Nothing. */
- }
- else if (TYPE_LENGTH (type)
- != TYPE_LENGTH (value_type (result_val)))
- error (_("DW_OP_reinterpret has wrong size"));
- else
- result_val
- = value_from_contents (type,
- value_contents_all (result_val).data ());
- }
- break;
- case DW_OP_push_object_address:
- /* Return the address of the object we are currently observing. */
- if (this->m_addr_info == nullptr
- || (this->m_addr_info->valaddr.data () == nullptr
- && this->m_addr_info->addr == 0))
- error (_("Location address is not set."));
- result_val
- = value_from_ulongest (address_type, this->m_addr_info->addr);
- break;
- default:
- error (_("Unhandled dwarf expression opcode 0x%x"), op);
- }
- /* Most things push a result value. */
- gdb_assert (result_val != NULL);
- push (result_val, in_stack_memory);
- no_push:
- ;
- }
- /* To simplify our main caller, if the result is an implicit
- pointer, then make a pieced value. This is ok because we can't
- have implicit pointers in contexts where pieces are invalid. */
- if (this->m_location == DWARF_VALUE_IMPLICIT_POINTER)
- add_piece (8 * this->m_addr_size, 0);
- this->m_recursion_depth--;
- gdb_assert (this->m_recursion_depth >= 0);
- }
- void _initialize_dwarf2expr ();
- void
- _initialize_dwarf2expr ()
- {
- dwarf_arch_cookie
- = gdbarch_data_register_post_init (dwarf_gdbarch_types_init);
- }
|