gdb/dwarf2expr.h

   1 /* Dwarf2 Expression Evaluator
   2    Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
   3    Contributed by Daniel Berlin (dan@dberlin.org)
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #if !defined (DWARF2EXPR_H)
  22 #define DWARF2EXPR_H
  23
  24 /* The expression evaluator works with a dwarf_expr_context, describing
  25    its current state and its callbacks.  */
  26 struct dwarf_expr_context
  27 {
  28   /* The stack of values, allocated with xmalloc.  */
  29   CORE_ADDR *stack;
  30
  31   /* The number of values currently pushed on the stack, and the
  32      number of elements allocated to the stack.  */
  33   int stack_len, stack_allocated;
  34
  35   /* An opaque argument provided by the caller, which will be passed
  36      to all of the callback functions.  */
  37   void *baton;
  38
  39   /* Return the value of register number REGNUM.  LVALP will be set
  40      to the kind of lval this register is (generally lval_register
  41      for the current frame's registers or lval_memory for a register
  42      saved to the stack).  For lval_memory ADDRP will be set to the
  43      saved location of the register.  */
  44   CORE_ADDR (*read_reg) (void *baton, int regnum, enum lval_type *lvalp,
  45                          CORE_ADDR *addrp);
  46
  47   /* Read LENGTH bytes at ADDR into BUF.  */
  48   void (*read_mem) (void *baton, char *buf, CORE_ADDR addr,
  49                     size_t length);
  50
  51   /* Return the location expression for the frame base attribute, in
  52      START and LENGTH.  The result must be live until the current
  53      expression evaluation is complete.  */
  54   void (*get_frame_base) (void *baton, unsigned char **start,
  55                          size_t *length);
  56
  57   /* Return the thread-local storage address for
  58      DW_OP_GNU_push_tls_address.  */
  59   CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset);
  60
  61 #if 0
  62   /* Not yet implemented.  */
  63
  64   /* Return the location expression for the dwarf expression
  65      subroutine in the die at OFFSET in the current compilation unit.
  66      The result must be live until the current expression evaluation
  67      is complete.  */
  68   unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length);
  69
  70   /* Return the `object address' for DW_OP_push_object_address.  */
  71   CORE_ADDR (*get_object_address) (void *baton);
  72 #endif
  73
  74   /* The current depth of dwarf expression recursion, via DW_OP_call*,
  75      DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum
  76      depth we'll tolerate before raising an error.  */
  77   int recursion_depth, max_recursion_depth;
  78
  79   /* Non-zero if the result is in a register.  The register number
  80      will be in REGNUM, and the result will be the contents of the
  81      register.  */
  82   int in_reg;
  83
  84   /* If the result is in a register, the register number.  */
  85   int regnum;
  86 };
  87
  88 struct dwarf_expr_context *new_dwarf_expr_context ();
  89 void free_dwarf_expr_context (struct dwarf_expr_context *ctx);
  90
  91 void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value);
  92 void dwarf_expr_pop (struct dwarf_expr_context *ctx);
  93 void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr,
  94                       size_t len);
  95 CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
  96
  97
  98 unsigned char *read_uleb128 (unsigned char *buf, unsigned char *buf_end,
  99                              ULONGEST * r);
 100 unsigned char *read_sleb128 (unsigned char *buf, unsigned char *buf_end,
 101                              LONGEST * r);
 102
 103 #endif