| /* DWARF 2 Expression Evaluator. |
| |
| Copyright (C) 2001, 2002, 2003, 2005 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 2 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, write to the Free Software |
| Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| Boston, MA 02110-1301, USA. */ |
| |
| #if !defined (DWARF2EXPR_H) |
| #define DWARF2EXPR_H |
| |
| /* 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. */ |
| CORE_ADDR *stack; |
| |
| /* The number of values currently pushed on the stack, and the |
| number of elements allocated to the stack. */ |
| int stack_len, stack_allocated; |
| |
| /* 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, gdb_byte **start, size_t *length); |
| |
| /* Return the thread-local storage address for |
| DW_OP_GNU_push_tls_address. */ |
| CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); |
| |
| #if 0 |
| /* Not yet implemented. */ |
| |
| /* Return the location expression for the dwarf expression |
| subroutine in the die at OFFSET in the current compilation unit. |
| The result must be live until the current expression evaluation |
| is complete. */ |
| unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length); |
| |
| /* 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; |
| |
| /* Non-zero if the result is in a register. The register number |
| will be on the expression stack. */ |
| int in_reg; |
| |
| /* 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 in_reg flag, and the size given as the operand to |
| DW_OP_piece. We then pop the top value from the stack, clear the |
| in_reg flag, 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, with in_reg clear, 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. */ |
| struct dwarf_expr_piece |
| { |
| /* If IN_REG is zero, then the piece is in memory, and VALUE is its address. |
| If IN_REG is non-zero, then the piece is in a register, and VALUE |
| is the register number. */ |
| int in_reg; |
| |
| /* This piece's address or register number. */ |
| CORE_ADDR value; |
| |
| /* The length of the piece, in bytes. */ |
| ULONGEST size; |
| }; |
| |
| struct dwarf_expr_context *new_dwarf_expr_context (void); |
| void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
| |
| void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value); |
| void dwarf_expr_pop (struct dwarf_expr_context *ctx); |
| void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr, |
| size_t len); |
| CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
| |
| |
| gdb_byte *read_uleb128 (gdb_byte *buf, gdb_byte *buf_end, ULONGEST * r); |
| gdb_byte *read_sleb128 (gdb_byte *buf, gdb_byte *buf_end, LONGEST * r); |
| CORE_ADDR dwarf2_read_address (gdb_byte *buf, gdb_byte *buf_end, |
| int *bytes_read); |
| |
| #endif /* dwarf2expr.h */ |