| /* Definitions for expressions designed to be executed on the agent |
| Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. |
| |
| 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. */ |
| |
| #ifndef AGENTEXPR_H |
| #define AGENTEXPR_H |
| |
| #include "doublest.h" /* For DOUBLEST. */ |
| |
| /* It's sometimes useful to be able to debug programs that you can't |
| really stop for more than a fraction of a second. To this end, the |
| user can specify a tracepoint (like a breakpoint, but you don't |
| stop at it), and specify a bunch of expressions to record the |
| values of when that tracepoint is reached. As the program runs, |
| GDB collects the values. At any point (possibly while values are |
| still being collected), the user can display the collected values. |
| |
| This is used with remote debugging; we don't really support it on |
| native configurations. |
| |
| This means that expressions are being evaluated by the remote agent, |
| which doesn't have any access to the symbol table information, and |
| needs to be small and simple. |
| |
| The agent_expr routines and datatypes are a bytecode language |
| designed to be executed by the agent. Agent expressions work in |
| terms of fixed-width values, operators, memory references, and |
| register references. You can evaluate a agent expression just given |
| a bunch of memory and register values to sniff at; you don't need |
| any symbolic information like variable names, types, etc. |
| |
| GDB translates source expressions, whose meaning depends on |
| symbolic information, into agent bytecode expressions, whose meaning |
| is independent of symbolic information. This means the agent can |
| evaluate them on the fly without reference to data only available |
| to the host GDB. */ |
| |
| |
| /* Agent expression data structures. */ |
| |
| /* The type of an element of the agent expression stack. |
| The bytecode operation indicates which element we should access; |
| the value itself has no typing information. GDB generates all |
| bytecode streams, so we don't have to worry about type errors. */ |
| |
| union agent_val |
| { |
| LONGEST l; |
| DOUBLEST d; |
| }; |
| |
| /* A buffer containing a agent expression. */ |
| struct agent_expr |
| { |
| unsigned char *buf; |
| int len; /* number of characters used */ |
| int size; /* allocated size */ |
| CORE_ADDR scope; |
| }; |
| |
| |
| |
| |
| /* The actual values of the various bytecode operations. |
| |
| Other independent implementations of the agent bytecode engine will |
| rely on the exact values of these enums, and may not be recompiled |
| when we change this table. The numeric values should remain fixed |
| whenever possible. Thus, we assign them values explicitly here (to |
| allow gaps to form safely), and the disassembly table in |
| agentexpr.h behaves like an opcode map. If you want to see them |
| grouped logically, see doc/agentexpr.texi. */ |
| |
| enum agent_op |
| { |
| aop_float = 0x01, |
| aop_add = 0x02, |
| aop_sub = 0x03, |
| aop_mul = 0x04, |
| aop_div_signed = 0x05, |
| aop_div_unsigned = 0x06, |
| aop_rem_signed = 0x07, |
| aop_rem_unsigned = 0x08, |
| aop_lsh = 0x09, |
| aop_rsh_signed = 0x0a, |
| aop_rsh_unsigned = 0x0b, |
| aop_trace = 0x0c, |
| aop_trace_quick = 0x0d, |
| aop_log_not = 0x0e, |
| aop_bit_and = 0x0f, |
| aop_bit_or = 0x10, |
| aop_bit_xor = 0x11, |
| aop_bit_not = 0x12, |
| aop_equal = 0x13, |
| aop_less_signed = 0x14, |
| aop_less_unsigned = 0x15, |
| aop_ext = 0x16, |
| aop_ref8 = 0x17, |
| aop_ref16 = 0x18, |
| aop_ref32 = 0x19, |
| aop_ref64 = 0x1a, |
| aop_ref_float = 0x1b, |
| aop_ref_double = 0x1c, |
| aop_ref_long_double = 0x1d, |
| aop_l_to_d = 0x1e, |
| aop_d_to_l = 0x1f, |
| aop_if_goto = 0x20, |
| aop_goto = 0x21, |
| aop_const8 = 0x22, |
| aop_const16 = 0x23, |
| aop_const32 = 0x24, |
| aop_const64 = 0x25, |
| aop_reg = 0x26, |
| aop_end = 0x27, |
| aop_dup = 0x28, |
| aop_pop = 0x29, |
| aop_zero_ext = 0x2a, |
| aop_swap = 0x2b, |
| aop_trace16 = 0x30, |
| aop_last |
| }; |
| |
| |
| |
| /* Functions for building expressions. */ |
| |
| /* Allocate a new, empty agent expression. */ |
| extern struct agent_expr *new_agent_expr (CORE_ADDR); |
| |
| /* Free a agent expression. */ |
| extern void free_agent_expr (struct agent_expr *); |
| extern struct cleanup *make_cleanup_free_agent_expr (struct agent_expr *); |
| |
| /* Append a simple operator OP to EXPR. */ |
| extern void ax_simple (struct agent_expr *EXPR, enum agent_op OP); |
| |
| /* Append the floating-point prefix, for the next bytecode. */ |
| #define ax_float(EXPR) (ax_simple ((EXPR), aop_float)) |
| |
| /* Append a sign-extension instruction to EXPR, to extend an N-bit value. */ |
| extern void ax_ext (struct agent_expr *EXPR, int N); |
| |
| /* Append a zero-extension instruction to EXPR, to extend an N-bit value. */ |
| extern void ax_zero_ext (struct agent_expr *EXPR, int N); |
| |
| /* Append a trace_quick instruction to EXPR, to record N bytes. */ |
| extern void ax_trace_quick (struct agent_expr *EXPR, int N); |
| |
| /* Append a goto op to EXPR. OP is the actual op (must be aop_goto or |
| aop_if_goto). We assume we don't know the target offset yet, |
| because it's probably a forward branch, so we leave space in EXPR |
| for the target, and return the offset in EXPR of that space, so we |
| can backpatch it once we do know the target offset. Use ax_label |
| to do the backpatching. */ |
| extern int ax_goto (struct agent_expr *EXPR, enum agent_op OP); |
| |
| /* Suppose a given call to ax_goto returns some value PATCH. When you |
| know the offset TARGET that goto should jump to, call |
| ax_label (EXPR, PATCH, TARGET) |
| to patch TARGET into the ax_goto instruction. */ |
| extern void ax_label (struct agent_expr *EXPR, int patch, int target); |
| |
| /* Assemble code to push a constant on the stack. */ |
| extern void ax_const_l (struct agent_expr *EXPR, LONGEST l); |
| extern void ax_const_d (struct agent_expr *EXPR, LONGEST d); |
| |
| /* Assemble code to push the value of register number REG on the |
| stack. */ |
| extern void ax_reg (struct agent_expr *EXPR, int REG); |
| |
| |
| /* Functions for printing out expressions, and otherwise debugging |
| things. */ |
| |
| /* Disassemble the expression EXPR, writing to F. */ |
| extern void ax_print (struct ui_file *f, struct agent_expr * EXPR); |
| |
| /* An entry in the opcode map. */ |
| struct aop_map |
| { |
| |
| /* The name of the opcode. Null means that this entry is not a |
| valid opcode --- a hole in the opcode space. */ |
| char *name; |
| |
| /* All opcodes take no operands from the bytecode stream, or take |
| unsigned integers of various sizes. If this is a positive number |
| n, then the opcode is followed by an n-byte operand, which should |
| be printed as an unsigned integer. If this is zero, then the |
| opcode takes no operands from the bytecode stream. |
| |
| If we get more complicated opcodes in the future, don't add other |
| magic values of this; that's a crock. Add an `enum encoding' |
| field to this, or something like that. */ |
| int op_size; |
| |
| /* The size of the data operated upon, in bits, for bytecodes that |
| care about that (ref and const). Zero for all others. */ |
| int data_size; |
| |
| /* Number of stack elements consumed, and number produced. */ |
| int consumed, produced; |
| }; |
| |
| /* Map of the bytecodes, indexed by bytecode number. */ |
| extern struct aop_map aop_map[]; |
| |
| /* Different kinds of flaws an agent expression might have, as |
| detected by agent_reqs. */ |
| enum agent_flaws |
| { |
| agent_flaw_none = 0, /* code is good */ |
| |
| /* There is an invalid instruction in the stream. */ |
| agent_flaw_bad_instruction, |
| |
| /* There is an incomplete instruction at the end of the expression. */ |
| agent_flaw_incomplete_instruction, |
| |
| /* agent_reqs was unable to prove that every jump target is to a |
| valid offset. Valid offsets are within the bounds of the |
| expression, and to a valid instruction boundary. */ |
| agent_flaw_bad_jump, |
| |
| /* agent_reqs was unable to prove to its satisfaction that, for each |
| jump target location, the stack will have the same height whether |
| that location is reached via a jump or by straight execution. */ |
| agent_flaw_height_mismatch, |
| |
| /* agent_reqs was unable to prove that every instruction following |
| an unconditional jump was the target of some other jump. */ |
| agent_flaw_hole |
| }; |
| |
| /* Structure describing the requirements of a bytecode expression. */ |
| struct agent_reqs |
| { |
| |
| /* If the following is not equal to agent_flaw_none, the rest of the |
| information in this structure is suspect. */ |
| enum agent_flaws flaw; |
| |
| /* Number of elements left on stack at end; may be negative if expr |
| only consumes elements. */ |
| int final_height; |
| |
| /* Maximum and minimum stack height, relative to initial height. */ |
| int max_height, min_height; |
| |
| /* Largest `ref' or `const' opcode used, in bits. Zero means the |
| expression has no such instructions. */ |
| int max_data_size; |
| |
| /* Bit vector of registers used. Register R is used iff |
| |
| reg_mask[R / 8] & (1 << (R % 8)) |
| |
| is non-zero. Note! You may not assume that this bitmask is long |
| enough to hold bits for all the registers of the machine; the |
| agent expression code has no idea how many registers the machine |
| has. However, the bitmask is reg_mask_len bytes long, so the |
| valid register numbers run from 0 to reg_mask_len * 8 - 1. |
| |
| We're assuming eight-bit bytes. So sue me. |
| |
| The caller should free reg_list when done. */ |
| int reg_mask_len; |
| unsigned char *reg_mask; |
| }; |
| |
| |
| /* Given an agent expression AX, fill in an agent_reqs structure REQS |
| describing it. */ |
| extern void ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs); |
| |
| #endif /* AGENTEXPR_H */ |