| 1 |
25 |
jlechner |
/* GDB-specific functions for operating on agent expressions
|
| 2 |
|
|
Copyright (C) 1998, 1999, 2000, 2007, 2008 Free Software Foundation, Inc.
|
| 3 |
|
|
|
| 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 3 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, see <http://www.gnu.org/licenses/>. */
|
| 18 |
|
|
|
| 19 |
|
|
#ifndef AX_GDB_H
|
| 20 |
|
|
#define AX_GDB_H
|
| 21 |
|
|
|
| 22 |
|
|
struct expression;
|
| 23 |
|
|
|
| 24 |
|
|
/* Types and enums */
|
| 25 |
|
|
|
| 26 |
|
|
/* GDB stores expressions in the form of a flattened tree (struct
|
| 27 |
|
|
expression), so we just walk that tree and generate agent bytecodes
|
| 28 |
|
|
as we go along.
|
| 29 |
|
|
|
| 30 |
|
|
GDB's normal evaluation uses struct value, which contains the
|
| 31 |
|
|
expression's value as well as its address or the register it came
|
| 32 |
|
|
from. The `+' operator uses the value, whereas the unary `&'
|
| 33 |
|
|
operator will use the address portion. The `=' operator will use
|
| 34 |
|
|
the address or register number of its left hand side.
|
| 35 |
|
|
|
| 36 |
|
|
The issues are different when generating agent bytecode. Given a
|
| 37 |
|
|
variable reference expression, we should not necessarily generate
|
| 38 |
|
|
code to fetch its value, because the next operator may be `=' or
|
| 39 |
|
|
unary `&'. Instead, when we recurse on a subexpression, we
|
| 40 |
|
|
indicate whether we want that expression to produce an lvalue or an
|
| 41 |
|
|
rvalue. If we requested an lvalue, then the recursive call tells
|
| 42 |
|
|
us whether it generated code to compute an address on the stack, or
|
| 43 |
|
|
whether the lvalue lives in a register.
|
| 44 |
|
|
|
| 45 |
|
|
The `axs' prefix here means `agent expression, static', because
|
| 46 |
|
|
this is all static analysis of the expression, i.e. analysis which
|
| 47 |
|
|
doesn't depend on the contents of memory and registers. */
|
| 48 |
|
|
|
| 49 |
|
|
|
| 50 |
|
|
/* Different kinds of agent expression static values. */
|
| 51 |
|
|
enum axs_lvalue_kind
|
| 52 |
|
|
{
|
| 53 |
|
|
/* We generated code to compute the subexpression's value.
|
| 54 |
|
|
Constants and arithmetic operators yield this. */
|
| 55 |
|
|
axs_rvalue,
|
| 56 |
|
|
|
| 57 |
|
|
/* We generated code to yield the subexpression's value's address on
|
| 58 |
|
|
the top of the stack. If the caller needs an rvalue, it should
|
| 59 |
|
|
call require_rvalue to produce the rvalue from this address. */
|
| 60 |
|
|
axs_lvalue_memory,
|
| 61 |
|
|
|
| 62 |
|
|
/* We didn't generate any code, and the stack is undisturbed,
|
| 63 |
|
|
because the subexpression's value lives in a register; u.reg is
|
| 64 |
|
|
the register number. If the caller needs an rvalue, it should
|
| 65 |
|
|
call require_rvalue to produce the rvalue from this register
|
| 66 |
|
|
number. */
|
| 67 |
|
|
axs_lvalue_register
|
| 68 |
|
|
};
|
| 69 |
|
|
|
| 70 |
|
|
/* Structure describing what we got from a subexpression. Think of
|
| 71 |
|
|
this as parallel to value.h's enum lval_type, except that we're
|
| 72 |
|
|
describing a value which will exist when the expression is
|
| 73 |
|
|
evaluated in the future, not a value we have in our hand. */
|
| 74 |
|
|
struct axs_value
|
| 75 |
|
|
{
|
| 76 |
|
|
enum axs_lvalue_kind kind; /* see above */
|
| 77 |
|
|
|
| 78 |
|
|
/* The type of the subexpression. Even if lvalue == axs_lvalue_memory,
|
| 79 |
|
|
this is the type of the value itself; the value on the stack is a
|
| 80 |
|
|
"pointer to" an object of this type. */
|
| 81 |
|
|
struct type *type;
|
| 82 |
|
|
|
| 83 |
|
|
union
|
| 84 |
|
|
{
|
| 85 |
|
|
/* if kind == axs_lvalue_register, this is the register number */
|
| 86 |
|
|
int reg;
|
| 87 |
|
|
}
|
| 88 |
|
|
u;
|
| 89 |
|
|
};
|
| 90 |
|
|
|
| 91 |
|
|
|
| 92 |
|
|
/* Translating GDB expressions into agent expressions. */
|
| 93 |
|
|
|
| 94 |
|
|
/* Given a GDB expression EXPR, return bytecode to trace its value.
|
| 95 |
|
|
The result will use the `trace' and `trace_quick' bytecodes to
|
| 96 |
|
|
record the value of all memory touched by the expression, and leave
|
| 97 |
|
|
no values on the stack. The caller can then use the ax_reqs
|
| 98 |
|
|
function to discover which registers the expression uses. */
|
| 99 |
|
|
extern struct agent_expr *gen_trace_for_expr (CORE_ADDR, struct expression *);
|
| 100 |
|
|
|
| 101 |
|
|
#endif /* AX_GDB_H */
|
