| /* DWARF 2 Expression Evaluator. |
| |
| Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010 |
| 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 |
| |
| /* 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 dwarf expression stack. */ |
| |
| struct dwarf_stack_value |
| { |
| ULONGEST 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 |
| { |
| /* 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; |
| |
| /* An opaque argument provided by the caller, which will be passed |
| to all of the callback functions. */ |
| void *baton; |
| |
| /* Return the value of register number REGNUM. */ |
| CORE_ADDR (*read_reg) (void *baton, int regnum); |
| |
| /* Read LENGTH bytes at ADDR into BUF. */ |
| void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); |
| |
| /* 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. */ |
| void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length); |
| |
| /* Return the CFA for the frame. */ |
| CORE_ADDR (*get_frame_cfa) (void *baton); |
| |
| /* Return the thread-local storage address for |
| DW_OP_GNU_push_tls_address. */ |
| CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); |
| |
| /* Execute DW_AT_location expression for the DWARF expression subroutine in |
| the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it |
| being passed to and returned from the called DWARF subroutine. */ |
| void (*dwarf_call) (struct dwarf_expr_context *ctx, size_t die_offset); |
| |
| #if 0 |
| /* Not yet implemented. */ |
| |
| /* Return the `object address' for DW_OP_push_object_address. */ |
| CORE_ADDR (*get_object_address) (void *baton); |
| #endif |
| |
| /* 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 VALUE_LITERAL, a the current literal value's length and |
| data. */ |
| 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; |
| }; |
| |
| |
| /* 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 or literal value, for |
| DWARF_VALUE_REGISTER or DWARF_VALUE_STACK pieces. */ |
| ULONGEST 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; |
| } v; |
| |
| /* The length of the piece, in bits. */ |
| ULONGEST size; |
| /* The piece offset, in bits. */ |
| ULONGEST offset; |
| }; |
| |
| struct dwarf_expr_context *new_dwarf_expr_context (void); |
| void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
| struct cleanup * |
| make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
| |
| void dwarf_expr_push (struct dwarf_expr_context *ctx, ULONGEST value, |
| int in_stack_memory); |
| void dwarf_expr_pop (struct dwarf_expr_context *ctx); |
| void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
| size_t len); |
| ULONGEST dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
| CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n); |
| int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n); |
| |
| |
| const gdb_byte *read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
| ULONGEST * r); |
| const gdb_byte *read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
| LONGEST * r); |
| |
| const char *dwarf_stack_op_name (unsigned int, int); |
| |
| void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
| const char *); |
| |
| #endif /* dwarf2expr.h */ |