| /* DWARF 2 Expression Evaluator. |
| |
| Copyright (C) 2001-2017 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/>. */ |
| |
| #if !defined (DWARF2EXPR_H) |
| #define DWARF2EXPR_H |
| |
| #include "leb128.h" |
| #include "gdbtypes.h" |
| |
| /* The location of a value. */ |
| enum dwarf_value_location |
| { |
| /* The piece is in memory. |
| The value on the dwarf stack is its address. */ |
| DWARF_VALUE_MEMORY, |
| |
| /* The piece is in a register. |
| The value on the dwarf stack is the register number. */ |
| DWARF_VALUE_REGISTER, |
| |
| /* The piece is on the dwarf stack. */ |
| DWARF_VALUE_STACK, |
| |
| /* The piece is a literal. */ |
| DWARF_VALUE_LITERAL, |
| |
| /* The piece was optimized out. */ |
| DWARF_VALUE_OPTIMIZED_OUT, |
| |
| /* The piece is an implicit pointer. */ |
| DWARF_VALUE_IMPLICIT_POINTER |
| }; |
| |
| /* The dwarf expression stack. */ |
| |
| struct dwarf_stack_value |
| { |
| struct value *value; |
| |
| /* Non-zero if the piece is in memory and is known to be |
| on the program's stack. It is always ok to set this to zero. |
| This is used, for example, to optimize memory access from the target. |
| It can vastly speed up backtraces on long latency connections when |
| "set stack-cache on". */ |
| int in_stack_memory; |
| }; |
| |
| /* The expression evaluator works with a dwarf_expr_context, describing |
| its current state and its callbacks. */ |
| struct dwarf_expr_context |
| { |
| dwarf_expr_context (); |
| virtual ~dwarf_expr_context (); |
| |
| void push_address (CORE_ADDR value, int in_stack_memory); |
| void eval (const gdb_byte *addr, size_t len); |
| struct value *fetch (int n); |
| CORE_ADDR fetch_address (int n); |
| int fetch_in_stack_memory (int n); |
| |
| /* The stack of values, allocated with xmalloc. */ |
| struct dwarf_stack_value *stack; |
| |
| /* The number of values currently pushed on the stack, and the |
| number of elements allocated to the stack. */ |
| int stack_len, stack_allocated; |
| |
| /* Target architecture to use for address operations. */ |
| struct gdbarch *gdbarch; |
| |
| /* Target address size in bytes. */ |
| int addr_size; |
| |
| /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
| context and operations depending on DW_FORM_ref_addr are not allowed. */ |
| int ref_addr_size; |
| |
| /* Offset used to relocate DW_OP_addr and DW_OP_GNU_addr_index arguments. */ |
| CORE_ADDR offset; |
| |
| /* The current depth of dwarf expression recursion, via DW_OP_call*, |
| DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum |
| depth we'll tolerate before raising an error. */ |
| int recursion_depth, max_recursion_depth; |
| |
| /* Location of the value. */ |
| enum dwarf_value_location location; |
| |
| /* For DWARF_VALUE_LITERAL, the current literal value's length and |
| data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
| target DIE of sect_offset kind. */ |
| ULONGEST len; |
| const gdb_byte *data; |
| |
| /* Initialization status of variable: Non-zero if variable has been |
| initialized; zero otherwise. */ |
| int initialized; |
| |
| /* An array of pieces. PIECES points to its first element; |
| NUM_PIECES is its length. |
| |
| Each time DW_OP_piece is executed, we add a new element to the |
| end of this array, recording the current top of the stack, the |
| current location, and the size given as the operand to |
| DW_OP_piece. We then pop the top value from the stack, reset the |
| location, and resume evaluation. |
| |
| The Dwarf spec doesn't say whether DW_OP_piece pops the top value |
| from the stack. We do, ensuring that clients of this interface |
| expecting to see a value left on the top of the stack (say, code |
| evaluating frame base expressions or CFA's specified with |
| DW_CFA_def_cfa_expression) will get an error if the expression |
| actually marks all the values it computes as pieces. |
| |
| If an expression never uses DW_OP_piece, num_pieces will be zero. |
| (It would be nice to present these cases as expressions yielding |
| a single piece, so that callers need not distinguish between the |
| no-DW_OP_piece and one-DW_OP_piece cases. But expressions with |
| no DW_OP_piece operations have no value to place in a piece's |
| 'size' field; the size comes from the surrounding data. So the |
| two cases need to be handled separately.) */ |
| int num_pieces; |
| struct dwarf_expr_piece *pieces; |
| |
| /* Return the value of register number REGNUM (a DWARF register number), |
| read as an address. */ |
| virtual CORE_ADDR read_addr_from_reg (int regnum) = 0; |
| |
| /* Return a value of type TYPE, stored in register number REGNUM |
| of the frame associated to the given BATON. |
| |
| REGNUM is a DWARF register number. */ |
| virtual struct value *get_reg_value (struct type *type, int regnum) = 0; |
| |
| /* Read LENGTH bytes at ADDR into BUF. */ |
| virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length) = 0; |
| |
| /* Return the location expression for the frame base attribute, in |
| START and LENGTH. The result must be live until the current |
| expression evaluation is complete. */ |
| virtual void get_frame_base (const gdb_byte **start, size_t *length) = 0; |
| |
| /* Return the CFA for the frame. */ |
| virtual CORE_ADDR get_frame_cfa () = 0; |
| |
| /* Return the PC for the frame. */ |
| virtual CORE_ADDR get_frame_pc () |
| { |
| error (_("%s is invalid in this context"), "DW_OP_GNU_implicit_pointer"); |
| } |
| |
| /* Return the thread-local storage address for |
| DW_OP_GNU_push_tls_address or DW_OP_form_tls_address. */ |
| virtual CORE_ADDR get_tls_address (CORE_ADDR offset) = 0; |
| |
| /* Execute DW_AT_location expression for the DWARF expression |
| subroutine in the DIE at DIE_OFFSET in the CU. Do not touch |
| STACK while it being passed to and returned from the called DWARF |
| subroutine. */ |
| virtual void dwarf_call (cu_offset die_offset) = 0; |
| |
| /* Return the base type given by the indicated DIE. This can throw |
| an exception if the DIE is invalid or does not represent a base |
| type. SIZE is non-zero if this function should verify that the |
| resulting type has the correct size. */ |
| virtual struct type *get_base_type (cu_offset die, int size) |
| { |
| /* Anything will do. */ |
| return builtin_type (this->gdbarch)->builtin_int; |
| } |
| |
| /* Push on DWARF stack an entry evaluated for DW_TAG_GNU_call_site's |
| parameter matching KIND and KIND_U at the caller of specified BATON. |
| If DEREF_SIZE is not -1 then use DW_AT_GNU_call_site_data_value instead of |
| DW_AT_GNU_call_site_value. */ |
| virtual void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind, |
| union call_site_parameter_u kind_u, |
| int deref_size) = 0; |
| |
| /* Return the address indexed by DW_OP_GNU_addr_index. |
| This can throw an exception if the index is out of range. */ |
| virtual CORE_ADDR get_addr_index (unsigned int index) = 0; |
| |
| /* Return the `object address' for DW_OP_push_object_address. */ |
| virtual CORE_ADDR get_object_address () = 0; |
| |
| private: |
| |
| struct type *address_type () const; |
| void grow_stack (size_t need); |
| void push (struct value *value, int in_stack_memory); |
| int stack_empty_p () const; |
| void add_piece (ULONGEST size, ULONGEST offset); |
| void execute_stack_op (const gdb_byte *op_ptr, const gdb_byte *op_end); |
| void pop (); |
| }; |
| |
| |
| /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
| struct dwarf_expr_piece |
| { |
| enum dwarf_value_location location; |
| |
| union |
| { |
| struct |
| { |
| /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ |
| CORE_ADDR addr; |
| /* Non-zero if the piece is known to be in memory and on |
| the program's stack. */ |
| int in_stack_memory; |
| } mem; |
| |
| /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ |
| int regno; |
| |
| /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ |
| struct value *value; |
| |
| struct |
| { |
| /* A pointer to the data making up this piece, |
| for DWARF_VALUE_LITERAL pieces. */ |
| const gdb_byte *data; |
| /* The length of the available data. */ |
| ULONGEST length; |
| } literal; |
| |
| /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ |
| struct |
| { |
| /* The referent DIE from DW_OP_GNU_implicit_pointer. */ |
| sect_offset die; |
| /* The byte offset into the resulting data. */ |
| LONGEST offset; |
| } ptr; |
| } v; |
| |
| /* The length of the piece, in bits. */ |
| ULONGEST size; |
| /* The piece offset, in bits. */ |
| ULONGEST offset; |
| }; |
| |
| void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
| const char *); |
| |
| int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); |
| |
| int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, |
| const gdb_byte *buf_end, |
| CORE_ADDR *deref_size_return); |
| |
| int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, |
| CORE_ADDR *fb_offset_return); |
| |
| int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, |
| const gdb_byte *buf_end, |
| CORE_ADDR *sp_offset_return); |
| |
| /* Wrappers around the leb128 reader routines to simplify them for our |
| purposes. */ |
| |
| static inline const gdb_byte * |
| gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
| uint64_t *r) |
| { |
| size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); |
| |
| if (bytes_read == 0) |
| return NULL; |
| return buf + bytes_read; |
| } |
| |
| static inline const gdb_byte * |
| gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
| int64_t *r) |
| { |
| size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); |
| |
| if (bytes_read == 0) |
| return NULL; |
| return buf + bytes_read; |
| } |
| |
| static inline const gdb_byte * |
| gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) |
| { |
| size_t bytes_read = skip_leb128 (buf, buf_end); |
| |
| if (bytes_read == 0) |
| return NULL; |
| return buf + bytes_read; |
| } |
| |
| extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, |
| const gdb_byte *buf_end, |
| uint64_t *r); |
| |
| extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, |
| const gdb_byte *buf_end, |
| int64_t *r); |
| |
| extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, |
| const gdb_byte *buf_end); |
| |
| #endif /* dwarf2expr.h */ |