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479fdd26ee
Return NULL if passed NULL. * frame.h: Declare it. * expression.h (union exp_element): Add field block. * parse.c (write_exp_elt_block): New function. * expression.h (OP_VAR_VALUE): Now takes additional struct block *. * *-exp.y: Write block for OP_VAR_VALUE. * eval.c, expprint.c, parse.c: Deal with block for OP_VAR_VALUE. * valops.c, value.h (value_of_variable), callers: Add second argument, for block.
1217 lines
35 KiB
C
1217 lines
35 KiB
C
/* Evaluate expressions for GDB.
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Copyright 1986, 1987, 1989, 1991, 1992 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "defs.h"
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#include "symtab.h"
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#include "gdbtypes.h"
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#include "value.h"
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#include "expression.h"
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#include "target.h"
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#include "frame.h"
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#include "language.h" /* For CAST_IS_CONVERSION */
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/* Values of NOSIDE argument to eval_subexp. */
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enum noside
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{ EVAL_NORMAL,
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EVAL_SKIP, /* Only effect is to increment pos. */
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EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
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call any functions. The value
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returned will have the correct
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type, and will have an
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approximately correct lvalue
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type (inaccuracy: anything that is
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listed as being in a register in
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the function in which it was
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declared will be lval_register). */
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};
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/* Prototypes for local functions. */
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static value
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evaluate_subexp_for_sizeof PARAMS ((struct expression *, int *));
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static value
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evaluate_subexp_with_coercion PARAMS ((struct expression *, int *,
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enum noside));
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static value
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evaluate_subexp_for_address PARAMS ((struct expression *, int *,
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enum noside));
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static value
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evaluate_subexp PARAMS ((struct type *, struct expression *, int *,
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enum noside));
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/* Parse the string EXP as a C expression, evaluate it,
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and return the result as a number. */
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CORE_ADDR
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parse_and_eval_address (exp)
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char *exp;
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{
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struct expression *expr = parse_expression (exp);
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register CORE_ADDR addr;
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register struct cleanup *old_chain =
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make_cleanup (free_current_contents, &expr);
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addr = value_as_pointer (evaluate_expression (expr));
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do_cleanups (old_chain);
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return addr;
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}
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/* Like parse_and_eval_address but takes a pointer to a char * variable
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and advanced that variable across the characters parsed. */
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CORE_ADDR
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parse_and_eval_address_1 (expptr)
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char **expptr;
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{
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struct expression *expr = parse_exp_1 (expptr, (struct block *)0, 0);
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register CORE_ADDR addr;
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register struct cleanup *old_chain =
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make_cleanup (free_current_contents, &expr);
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addr = value_as_pointer (evaluate_expression (expr));
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do_cleanups (old_chain);
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return addr;
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}
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value
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parse_and_eval (exp)
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char *exp;
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{
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struct expression *expr = parse_expression (exp);
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register value val;
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register struct cleanup *old_chain
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= make_cleanup (free_current_contents, &expr);
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val = evaluate_expression (expr);
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do_cleanups (old_chain);
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return val;
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}
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/* Parse up to a comma (or to a closeparen)
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in the string EXPP as an expression, evaluate it, and return the value.
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EXPP is advanced to point to the comma. */
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value
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parse_to_comma_and_eval (expp)
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char **expp;
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{
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struct expression *expr = parse_exp_1 (expp, (struct block *) 0, 1);
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register value val;
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register struct cleanup *old_chain
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= make_cleanup (free_current_contents, &expr);
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val = evaluate_expression (expr);
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do_cleanups (old_chain);
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return val;
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}
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/* Evaluate an expression in internal prefix form
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such as is constructed by parse.y.
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See expression.h for info on the format of an expression. */
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static value evaluate_subexp ();
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static value evaluate_subexp_for_address ();
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static value evaluate_subexp_for_sizeof ();
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static value evaluate_subexp_with_coercion ();
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value
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evaluate_expression (exp)
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struct expression *exp;
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{
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int pc = 0;
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return evaluate_subexp (NULL_TYPE, exp, &pc, EVAL_NORMAL);
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}
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/* Evaluate an expression, avoiding all memory references
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and getting a value whose type alone is correct. */
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value
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evaluate_type (exp)
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struct expression *exp;
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{
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int pc = 0;
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return evaluate_subexp (NULL_TYPE, exp, &pc, EVAL_AVOID_SIDE_EFFECTS);
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}
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static value
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evaluate_subexp (expect_type, exp, pos, noside)
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struct type *expect_type;
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register struct expression *exp;
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register int *pos;
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enum noside noside;
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{
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enum exp_opcode op;
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int tem, tem2, tem3;
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register int pc, pc2, oldpos;
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register value arg1, arg2, arg3;
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struct type *type;
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int nargs;
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value *argvec;
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pc = (*pos)++;
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op = exp->elts[pc].opcode;
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switch (op)
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{
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case OP_SCOPE:
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tem = longest_to_int (exp->elts[pc + 2].longconst);
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(*pos) += 4 + BYTES_TO_EXP_ELEM (tem + 1);
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arg1 = value_struct_elt_for_reference (exp->elts[pc + 1].type,
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0,
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exp->elts[pc + 1].type,
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&exp->elts[pc + 3].string,
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expect_type);
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if (arg1 == NULL)
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error ("There is no field named %s", &exp->elts[pc + 3].string);
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return arg1;
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case OP_LONG:
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(*pos) += 3;
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return value_from_longest (exp->elts[pc + 1].type,
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exp->elts[pc + 2].longconst);
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case OP_DOUBLE:
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(*pos) += 3;
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return value_from_double (exp->elts[pc + 1].type,
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exp->elts[pc + 2].doubleconst);
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case OP_VAR_VALUE:
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(*pos) += 3;
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if (noside == EVAL_SKIP)
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goto nosideret;
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if (noside == EVAL_AVOID_SIDE_EFFECTS)
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{
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struct symbol * sym = exp->elts[pc + 1].symbol;
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enum lval_type lv;
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switch (SYMBOL_CLASS (sym))
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{
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case LOC_CONST:
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case LOC_LABEL:
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case LOC_CONST_BYTES:
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lv = not_lval;
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break;
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case LOC_REGISTER:
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case LOC_REGPARM:
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lv = lval_register;
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break;
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default:
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lv = lval_memory;
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break;
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}
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return value_zero (SYMBOL_TYPE (sym), lv);
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}
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else
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return value_of_variable (exp->elts[pc + 2].symbol,
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exp->elts[pc + 1].block);
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case OP_LAST:
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(*pos) += 2;
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return
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access_value_history (longest_to_int (exp->elts[pc + 1].longconst));
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case OP_REGISTER:
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(*pos) += 2;
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return value_of_register (longest_to_int (exp->elts[pc + 1].longconst));
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case OP_BOOL:
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(*pos) += 2;
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return value_from_longest (builtin_type_chill_bool,
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exp->elts[pc + 1].longconst);
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case OP_INTERNALVAR:
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(*pos) += 2;
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return value_of_internalvar (exp->elts[pc + 1].internalvar);
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case OP_STRING:
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tem = longest_to_int (exp->elts[pc + 1].longconst);
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(*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
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if (noside == EVAL_SKIP)
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goto nosideret;
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return value_string (&exp->elts[pc + 2].string, tem);
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case OP_BITSTRING:
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error ("support for OP_BITSTRING unimplemented");
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break;
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case OP_ARRAY:
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(*pos) += 3;
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tem2 = longest_to_int (exp->elts[pc + 1].longconst);
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tem3 = longest_to_int (exp->elts[pc + 2].longconst);
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nargs = tem3 - tem2 + 1;
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argvec = (value *) alloca (sizeof (value) * nargs);
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for (tem = 0; tem < nargs; tem++)
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{
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/* Ensure that array expressions are coerced into pointer objects. */
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argvec[tem] = evaluate_subexp_with_coercion (exp, pos, noside);
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}
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if (noside == EVAL_SKIP)
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goto nosideret;
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return (value_array (tem2, tem3, argvec));
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break;
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case TERNOP_COND:
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/* Skip third and second args to evaluate the first one. */
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arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
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if (value_logical_not (arg1))
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{
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evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
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return evaluate_subexp (NULL_TYPE, exp, pos, noside);
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}
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else
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{
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arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
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evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
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return arg2;
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}
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case OP_FUNCALL:
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(*pos) += 2;
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op = exp->elts[*pos].opcode;
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if (op == STRUCTOP_MEMBER || op == STRUCTOP_MPTR)
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{
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int fnptr;
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nargs = longest_to_int (exp->elts[pc + 1].longconst) + 1;
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/* First, evaluate the structure into arg2 */
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pc2 = (*pos)++;
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if (noside == EVAL_SKIP)
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goto nosideret;
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if (op == STRUCTOP_MEMBER)
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{
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arg2 = evaluate_subexp_for_address (exp, pos, noside);
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}
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else
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{
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arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
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}
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/* If the function is a virtual function, then the
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aggregate value (providing the structure) plays
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its part by providing the vtable. Otherwise,
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it is just along for the ride: call the function
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directly. */
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arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
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fnptr = longest_to_int (value_as_long (arg1));
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if (METHOD_PTR_IS_VIRTUAL(fnptr))
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{
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int fnoffset = METHOD_PTR_TO_VOFFSET(fnptr);
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struct type *basetype;
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struct type *domain_type =
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TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1)));
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int i, j;
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basetype = TYPE_TARGET_TYPE (VALUE_TYPE (arg2));
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if (domain_type != basetype)
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arg2 = value_cast(lookup_pointer_type (domain_type), arg2);
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basetype = TYPE_VPTR_BASETYPE (domain_type);
|
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for (i = TYPE_NFN_FIELDS (basetype) - 1; i >= 0; i--)
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{
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struct fn_field *f = TYPE_FN_FIELDLIST1 (basetype, i);
|
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/* If one is virtual, then all are virtual. */
|
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if (TYPE_FN_FIELD_VIRTUAL_P (f, 0))
|
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for (j = TYPE_FN_FIELDLIST_LENGTH (basetype, i) - 1; j >= 0; --j)
|
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if (TYPE_FN_FIELD_VOFFSET (f, j) == fnoffset)
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{
|
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value temp = value_ind (arg2);
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arg1 = value_virtual_fn_field (&temp, f, j, domain_type, 0);
|
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arg2 = value_addr (temp);
|
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goto got_it;
|
||
}
|
||
}
|
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if (i < 0)
|
||
error ("virtual function at index %d not found", fnoffset);
|
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}
|
||
else
|
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{
|
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VALUE_TYPE (arg1) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg1)));
|
||
}
|
||
got_it:
|
||
|
||
/* Now, say which argument to start evaluating from */
|
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tem = 2;
|
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}
|
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else if (op == STRUCTOP_STRUCT || op == STRUCTOP_PTR)
|
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{
|
||
/* Hair for method invocations */
|
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int tem2;
|
||
|
||
nargs = longest_to_int (exp->elts[pc + 1].longconst) + 1;
|
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/* First, evaluate the structure into arg2 */
|
||
pc2 = (*pos)++;
|
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tem2 = longest_to_int (exp->elts[pc2 + 1].longconst);
|
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*pos += 3 + BYTES_TO_EXP_ELEM (tem2 + 1);
|
||
if (noside == EVAL_SKIP)
|
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goto nosideret;
|
||
|
||
if (op == STRUCTOP_STRUCT)
|
||
{
|
||
/* If v is a variable in a register, and the user types
|
||
v.method (), this will produce an error, because v has
|
||
no address.
|
||
|
||
A possible way around this would be to allocate a
|
||
copy of the variable on the stack, copy in the
|
||
contents, call the function, and copy out the
|
||
contents. I.e. convert this from call by reference
|
||
to call by copy-return (or whatever it's called).
|
||
However, this does not work because it is not the
|
||
same: the method being called could stash a copy of
|
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the address, and then future uses through that address
|
||
(after the method returns) would be expected to
|
||
use the variable itself, not some copy of it. */
|
||
arg2 = evaluate_subexp_for_address (exp, pos, noside);
|
||
}
|
||
else
|
||
{
|
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arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
}
|
||
/* Now, say which argument to start evaluating from */
|
||
tem = 2;
|
||
}
|
||
else
|
||
{
|
||
nargs = longest_to_int (exp->elts[pc + 1].longconst);
|
||
tem = 0;
|
||
}
|
||
/* Allocate arg vector, including space for the function to be
|
||
called in argvec[0] and a terminating NULL */
|
||
argvec = (value *) alloca (sizeof (value) * (nargs + 2));
|
||
for (; tem <= nargs; tem++)
|
||
/* Ensure that array expressions are coerced into pointer objects. */
|
||
argvec[tem] = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
|
||
/* signal end of arglist */
|
||
argvec[tem] = 0;
|
||
|
||
if (op == STRUCTOP_STRUCT || op == STRUCTOP_PTR)
|
||
{
|
||
int static_memfuncp;
|
||
value temp = arg2;
|
||
|
||
argvec[1] = arg2;
|
||
argvec[0] =
|
||
value_struct_elt (&temp, argvec+1, &exp->elts[pc2 + 2].string,
|
||
&static_memfuncp,
|
||
op == STRUCTOP_STRUCT
|
||
? "structure" : "structure pointer");
|
||
if (VALUE_OFFSET (temp))
|
||
{
|
||
arg2 = value_from_longest (lookup_pointer_type (VALUE_TYPE (temp)),
|
||
VALUE_ADDRESS (temp)+VALUE_OFFSET (temp));
|
||
argvec[1] = arg2;
|
||
}
|
||
if (static_memfuncp)
|
||
{
|
||
argvec[1] = argvec[0];
|
||
nargs--;
|
||
argvec++;
|
||
}
|
||
}
|
||
else if (op == STRUCTOP_MEMBER || op == STRUCTOP_MPTR)
|
||
{
|
||
argvec[1] = arg2;
|
||
argvec[0] = arg1;
|
||
}
|
||
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
/* If the return type doesn't look like a function type, call an
|
||
error. This can happen if somebody tries to turn a variable into
|
||
a function call. This is here because people often want to
|
||
call, eg, strcmp, which gdb doesn't know is a function. If
|
||
gdb isn't asked for it's opinion (ie. through "whatis"),
|
||
it won't offer it. */
|
||
|
||
struct type *ftype =
|
||
TYPE_TARGET_TYPE (VALUE_TYPE (argvec[0]));
|
||
|
||
if (ftype)
|
||
return allocate_value (TYPE_TARGET_TYPE (VALUE_TYPE (argvec[0])));
|
||
else
|
||
error ("Expression of type other than \"Function returning ...\" used as function");
|
||
}
|
||
return call_function_by_hand (argvec[0], nargs, argvec + 1);
|
||
|
||
case STRUCTOP_STRUCT:
|
||
tem = longest_to_int (exp->elts[pc + 1].longconst);
|
||
(*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return value_zero (lookup_struct_elt_type (VALUE_TYPE (arg1),
|
||
&exp->elts[pc + 2].string,
|
||
0),
|
||
lval_memory);
|
||
else
|
||
{
|
||
value temp = arg1;
|
||
return value_struct_elt (&temp, (value *)0, &exp->elts[pc + 2].string,
|
||
(int *) 0, "structure");
|
||
}
|
||
|
||
case STRUCTOP_PTR:
|
||
tem = longest_to_int (exp->elts[pc + 1].longconst);
|
||
(*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return value_zero (lookup_struct_elt_type (VALUE_TYPE (arg1),
|
||
&exp->elts[pc + 2].string,
|
||
0),
|
||
lval_memory);
|
||
else
|
||
{
|
||
value temp = arg1;
|
||
return value_struct_elt (&temp, (value *)0, &exp->elts[pc + 2].string,
|
||
(int *) 0, "structure pointer");
|
||
}
|
||
|
||
case STRUCTOP_MEMBER:
|
||
arg1 = evaluate_subexp_for_address (exp, pos, noside);
|
||
goto handle_pointer_to_member;
|
||
case STRUCTOP_MPTR:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
handle_pointer_to_member:
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (TYPE_CODE (VALUE_TYPE (arg2)) != TYPE_CODE_PTR)
|
||
goto bad_pointer_to_member;
|
||
type = TYPE_TARGET_TYPE (VALUE_TYPE (arg2));
|
||
if (TYPE_CODE (type) == TYPE_CODE_METHOD)
|
||
error ("not implemented: pointer-to-method in pointer-to-member construct");
|
||
if (TYPE_CODE (type) != TYPE_CODE_MEMBER)
|
||
goto bad_pointer_to_member;
|
||
/* Now, convert these values to an address. */
|
||
arg1 = value_cast (lookup_pointer_type (TYPE_DOMAIN_TYPE (type)),
|
||
arg1);
|
||
arg3 = value_from_longest (lookup_pointer_type (TYPE_TARGET_TYPE (type)),
|
||
value_as_long (arg1) + value_as_long (arg2));
|
||
return value_ind (arg3);
|
||
bad_pointer_to_member:
|
||
error("non-pointer-to-member value used in pointer-to-member construct");
|
||
|
||
case BINOP_CONCAT:
|
||
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
return value_concat (arg1, arg2);
|
||
|
||
case BINOP_ASSIGN:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
return value_assign (arg1, arg2);
|
||
|
||
case BINOP_ASSIGN_MODIFY:
|
||
(*pos) += 2;
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
op = exp->elts[pc + 1].opcode;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, BINOP_ASSIGN_MODIFY, op);
|
||
else if (op == BINOP_ADD)
|
||
arg2 = value_add (arg1, arg2);
|
||
else if (op == BINOP_SUB)
|
||
arg2 = value_sub (arg1, arg2);
|
||
else
|
||
arg2 = value_binop (arg1, arg2, op);
|
||
return value_assign (arg1, arg2);
|
||
|
||
case BINOP_ADD:
|
||
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
return value_add (arg1, arg2);
|
||
|
||
case BINOP_SUB:
|
||
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
return value_sub (arg1, arg2);
|
||
|
||
case BINOP_MUL:
|
||
case BINOP_DIV:
|
||
case BINOP_REM:
|
||
case BINOP_MOD:
|
||
case BINOP_LSH:
|
||
case BINOP_RSH:
|
||
case BINOP_BITWISE_AND:
|
||
case BINOP_BITWISE_IOR:
|
||
case BINOP_BITWISE_XOR:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS
|
||
&& (op == BINOP_DIV || op == BINOP_REM || op == BINOP_MOD))
|
||
return value_zero (VALUE_TYPE (arg1), not_lval);
|
||
else
|
||
return value_binop (arg1, arg2, op);
|
||
|
||
case BINOP_SUBSCRIPT:
|
||
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
/* If the user attempts to subscript something that has no target
|
||
type (like a plain int variable for example), then report this
|
||
as an error. */
|
||
|
||
type = TYPE_TARGET_TYPE (VALUE_TYPE (arg1));
|
||
if (type)
|
||
return value_zero (type, VALUE_LVAL (arg1));
|
||
else
|
||
error ("cannot subscript something of type `%s'",
|
||
TYPE_NAME (VALUE_TYPE (arg1)));
|
||
}
|
||
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
else
|
||
return value_subscript (arg1, arg2);
|
||
|
||
case MULTI_SUBSCRIPT:
|
||
(*pos) += 2;
|
||
nargs = longest_to_int (exp->elts[pc + 1].longconst);
|
||
arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
while (nargs-- > 0)
|
||
{
|
||
arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
|
||
/* FIXME: EVAL_SKIP handling may not be correct. */
|
||
if (noside == EVAL_SKIP)
|
||
{
|
||
if (nargs > 0)
|
||
{
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
goto nosideret;
|
||
}
|
||
}
|
||
/* FIXME: EVAL_AVOID_SIDE_EFFECTS handling may not be correct. */
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
/* If the user attempts to subscript something that has no target
|
||
type (like a plain int variable for example), then report this
|
||
as an error. */
|
||
|
||
type = TYPE_TARGET_TYPE (VALUE_TYPE (arg1));
|
||
if (type != NULL)
|
||
{
|
||
arg1 = value_zero (type, VALUE_LVAL (arg1));
|
||
noside = EVAL_SKIP;
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
error ("cannot subscript something of type `%s'",
|
||
TYPE_NAME (VALUE_TYPE (arg1)));
|
||
}
|
||
}
|
||
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
arg1 = value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
arg1 = value_subscript (arg1, arg2);
|
||
}
|
||
}
|
||
return (arg1);
|
||
|
||
case BINOP_LOGICAL_AND:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
{
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
goto nosideret;
|
||
}
|
||
|
||
oldpos = *pos;
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
|
||
*pos = oldpos;
|
||
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_logical_not (arg1);
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos,
|
||
(tem ? EVAL_SKIP : noside));
|
||
return value_from_longest (builtin_type_int,
|
||
(LONGEST) (!tem && !value_logical_not (arg2)));
|
||
}
|
||
|
||
case BINOP_LOGICAL_OR:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
{
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
goto nosideret;
|
||
}
|
||
|
||
oldpos = *pos;
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
|
||
*pos = oldpos;
|
||
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_logical_not (arg1);
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos,
|
||
(!tem ? EVAL_SKIP : noside));
|
||
return value_from_longest (builtin_type_int,
|
||
(LONGEST) (!tem || !value_logical_not (arg2)));
|
||
}
|
||
|
||
case BINOP_EQUAL:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_equal (arg1, arg2);
|
||
return value_from_longest (builtin_type_int, (LONGEST) tem);
|
||
}
|
||
|
||
case BINOP_NOTEQUAL:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_equal (arg1, arg2);
|
||
return value_from_longest (builtin_type_int, (LONGEST) ! tem);
|
||
}
|
||
|
||
case BINOP_LESS:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_less (arg1, arg2);
|
||
return value_from_longest (builtin_type_int, (LONGEST) tem);
|
||
}
|
||
|
||
case BINOP_GTR:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_less (arg2, arg1);
|
||
return value_from_longest (builtin_type_int, (LONGEST) tem);
|
||
}
|
||
|
||
case BINOP_GEQ:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_less (arg2, arg1) || value_equal (arg1, arg2);
|
||
return value_from_longest (builtin_type_int, (LONGEST) tem);
|
||
}
|
||
|
||
case BINOP_LEQ:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (binop_user_defined_p (op, arg1, arg2))
|
||
{
|
||
return value_x_binop (arg1, arg2, op, OP_NULL);
|
||
}
|
||
else
|
||
{
|
||
tem = value_less (arg1, arg2) || value_equal (arg1, arg2);
|
||
return value_from_longest (builtin_type_int, (LONGEST) tem);
|
||
}
|
||
|
||
case BINOP_REPEAT:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (TYPE_CODE (VALUE_TYPE (arg2)) != TYPE_CODE_INT)
|
||
error ("Non-integral right operand for \"@\" operator.");
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return allocate_repeat_value (VALUE_TYPE (arg1),
|
||
longest_to_int (value_as_long (arg2)));
|
||
else
|
||
return value_repeat (arg1, longest_to_int (value_as_long (arg2)));
|
||
|
||
case BINOP_COMMA:
|
||
evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
return evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
|
||
case UNOP_NEG:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (unop_user_defined_p (op, arg1))
|
||
return value_x_unop (arg1, op);
|
||
else
|
||
return value_neg (arg1);
|
||
|
||
case UNOP_COMPLEMENT:
|
||
/* C++: check for and handle destructor names. */
|
||
op = exp->elts[*pos].opcode;
|
||
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (unop_user_defined_p (UNOP_COMPLEMENT, arg1))
|
||
return value_x_unop (arg1, UNOP_COMPLEMENT);
|
||
else
|
||
return value_complement (arg1);
|
||
|
||
case UNOP_LOGICAL_NOT:
|
||
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (unop_user_defined_p (op, arg1))
|
||
return value_x_unop (arg1, op);
|
||
else
|
||
return value_from_longest (builtin_type_int,
|
||
(LONGEST) value_logical_not (arg1));
|
||
|
||
case UNOP_IND:
|
||
if (expect_type && TYPE_CODE (expect_type) == TYPE_CODE_PTR)
|
||
expect_type = TYPE_TARGET_TYPE (expect_type);
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
if (TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_PTR
|
||
|| TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_REF
|
||
/* In C you can dereference an array to get the 1st elt. */
|
||
|| TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_ARRAY
|
||
)
|
||
return value_zero (TYPE_TARGET_TYPE (VALUE_TYPE (arg1)),
|
||
lval_memory);
|
||
else if (TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_INT)
|
||
/* GDB allows dereferencing an int. */
|
||
return value_zero (builtin_type_int, lval_memory);
|
||
else
|
||
error ("Attempt to take contents of a non-pointer value.");
|
||
}
|
||
return value_ind (arg1);
|
||
|
||
case UNOP_ADDR:
|
||
/* C++: check for and handle pointer to members. */
|
||
|
||
op = exp->elts[*pos].opcode;
|
||
|
||
if (noside == EVAL_SKIP)
|
||
{
|
||
if (op == OP_SCOPE)
|
||
{
|
||
int temm = longest_to_int (exp->elts[pc+3].longconst);
|
||
(*pos) += 3 + BYTES_TO_EXP_ELEM (temm + 1);
|
||
}
|
||
else
|
||
evaluate_subexp (expect_type, exp, pos, EVAL_SKIP);
|
||
goto nosideret;
|
||
}
|
||
|
||
return evaluate_subexp_for_address (exp, pos, noside);
|
||
|
||
case UNOP_SIZEOF:
|
||
if (noside == EVAL_SKIP)
|
||
{
|
||
evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
|
||
goto nosideret;
|
||
}
|
||
return evaluate_subexp_for_sizeof (exp, pos);
|
||
|
||
case UNOP_CAST:
|
||
(*pos) += 2;
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
return value_cast (exp->elts[pc + 1].type, arg1);
|
||
|
||
case UNOP_MEMVAL:
|
||
(*pos) += 2;
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP)
|
||
goto nosideret;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return value_zero (exp->elts[pc + 1].type, lval_memory);
|
||
else
|
||
return value_at_lazy (exp->elts[pc + 1].type,
|
||
value_as_pointer (arg1));
|
||
|
||
case UNOP_PREINCREMENT:
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
else if (unop_user_defined_p (op, arg1))
|
||
{
|
||
return value_x_unop (arg1, op);
|
||
}
|
||
else
|
||
{
|
||
arg2 = value_add (arg1, value_from_longest (builtin_type_char,
|
||
(LONGEST) 1));
|
||
return value_assign (arg1, arg2);
|
||
}
|
||
|
||
case UNOP_PREDECREMENT:
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
else if (unop_user_defined_p (op, arg1))
|
||
{
|
||
return value_x_unop (arg1, op);
|
||
}
|
||
else
|
||
{
|
||
arg2 = value_sub (arg1, value_from_longest (builtin_type_char,
|
||
(LONGEST) 1));
|
||
return value_assign (arg1, arg2);
|
||
}
|
||
|
||
case UNOP_POSTINCREMENT:
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
else if (unop_user_defined_p (op, arg1))
|
||
{
|
||
return value_x_unop (arg1, op);
|
||
}
|
||
else
|
||
{
|
||
arg2 = value_add (arg1, value_from_longest (builtin_type_char,
|
||
(LONGEST) 1));
|
||
value_assign (arg1, arg2);
|
||
return arg1;
|
||
}
|
||
|
||
case UNOP_POSTDECREMENT:
|
||
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
|
||
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
return arg1;
|
||
else if (unop_user_defined_p (op, arg1))
|
||
{
|
||
return value_x_unop (arg1, op);
|
||
}
|
||
else
|
||
{
|
||
arg2 = value_sub (arg1, value_from_longest (builtin_type_char,
|
||
(LONGEST) 1));
|
||
value_assign (arg1, arg2);
|
||
return arg1;
|
||
}
|
||
|
||
case OP_THIS:
|
||
(*pos) += 1;
|
||
return value_of_this (1);
|
||
|
||
case OP_TYPE:
|
||
error ("Attempt to use a type name as an expression");
|
||
|
||
default:
|
||
/* Removing this case and compiling with gcc -Wall reveals that
|
||
a lot of cases are hitting this case. Some of these should
|
||
probably be removed from expression.h (e.g. do we need a BINOP_SCOPE
|
||
and an OP_SCOPE?); others are legitimate expressions which are
|
||
(apparently) not fully implemented.
|
||
|
||
If there are any cases landing here which mean a user error,
|
||
then they should be separate cases, with more descriptive
|
||
error messages. */
|
||
|
||
error ("\
|
||
GDB does not (yet) know how to evaluated that kind of expression");
|
||
}
|
||
|
||
nosideret:
|
||
return value_from_longest (builtin_type_long, (LONGEST) 1);
|
||
}
|
||
|
||
/* Evaluate a subexpression of EXP, at index *POS,
|
||
and return the address of that subexpression.
|
||
Advance *POS over the subexpression.
|
||
If the subexpression isn't an lvalue, get an error.
|
||
NOSIDE may be EVAL_AVOID_SIDE_EFFECTS;
|
||
then only the type of the result need be correct. */
|
||
|
||
static value
|
||
evaluate_subexp_for_address (exp, pos, noside)
|
||
register struct expression *exp;
|
||
register int *pos;
|
||
enum noside noside;
|
||
{
|
||
enum exp_opcode op;
|
||
register int pc;
|
||
struct symbol *var;
|
||
|
||
pc = (*pos);
|
||
op = exp->elts[pc].opcode;
|
||
|
||
switch (op)
|
||
{
|
||
case UNOP_IND:
|
||
(*pos)++;
|
||
return evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
|
||
case UNOP_MEMVAL:
|
||
(*pos) += 3;
|
||
return value_cast (lookup_pointer_type (exp->elts[pc + 1].type),
|
||
evaluate_subexp (NULL_TYPE, exp, pos, noside));
|
||
|
||
case OP_VAR_VALUE:
|
||
var = exp->elts[pc + 2].symbol;
|
||
|
||
/* C++: The "address" of a reference should yield the address
|
||
* of the object pointed to. Let value_addr() deal with it. */
|
||
if (TYPE_CODE (SYMBOL_TYPE (var)) == TYPE_CODE_REF)
|
||
goto default_case;
|
||
|
||
(*pos) += 4;
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
struct type *type =
|
||
lookup_pointer_type (SYMBOL_TYPE (var));
|
||
enum address_class sym_class = SYMBOL_CLASS (var);
|
||
|
||
if (sym_class == LOC_CONST
|
||
|| sym_class == LOC_CONST_BYTES
|
||
|| sym_class == LOC_REGISTER
|
||
|| sym_class == LOC_REGPARM)
|
||
error ("Attempt to take address of register or constant.");
|
||
|
||
return
|
||
value_zero (type, not_lval);
|
||
}
|
||
else
|
||
return
|
||
locate_var_value
|
||
(var,
|
||
block_innermost_frame (exp->elts[pc + 1].block));
|
||
|
||
default:
|
||
default_case:
|
||
if (noside == EVAL_AVOID_SIDE_EFFECTS)
|
||
{
|
||
value x = evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
if (VALUE_LVAL (x) == lval_memory)
|
||
return value_zero (lookup_pointer_type (VALUE_TYPE (x)),
|
||
not_lval);
|
||
else
|
||
error ("Attempt to take address of non-lval");
|
||
}
|
||
return value_addr (evaluate_subexp (NULL_TYPE, exp, pos, noside));
|
||
}
|
||
}
|
||
|
||
/* Evaluate like `evaluate_subexp' except coercing arrays to pointers.
|
||
When used in contexts where arrays will be coerced anyway, this is
|
||
equivalent to `evaluate_subexp' but much faster because it avoids
|
||
actually fetching array contents (perhaps obsolete now that we have
|
||
VALUE_LAZY).
|
||
|
||
Note that we currently only do the coercion for C expressions, where
|
||
arrays are zero based and the coercion is correct. For other languages,
|
||
with nonzero based arrays, coercion loses. Use CAST_IS_CONVERSION
|
||
to decide if coercion is appropriate.
|
||
|
||
*/
|
||
|
||
static value
|
||
evaluate_subexp_with_coercion (exp, pos, noside)
|
||
register struct expression *exp;
|
||
register int *pos;
|
||
enum noside noside;
|
||
{
|
||
register enum exp_opcode op;
|
||
register int pc;
|
||
register value val;
|
||
struct symbol *var;
|
||
|
||
pc = (*pos);
|
||
op = exp->elts[pc].opcode;
|
||
|
||
switch (op)
|
||
{
|
||
case OP_VAR_VALUE:
|
||
var = exp->elts[pc + 2].symbol;
|
||
if (TYPE_CODE (SYMBOL_TYPE (var)) == TYPE_CODE_ARRAY
|
||
&& CAST_IS_CONVERSION)
|
||
{
|
||
(*pos) += 4;
|
||
val =
|
||
locate_var_value
|
||
(var, block_innermost_frame (exp->elts[pc + 1].block));
|
||
return value_cast (lookup_pointer_type (TYPE_TARGET_TYPE (SYMBOL_TYPE (var))),
|
||
val);
|
||
}
|
||
/* FALLTHROUGH */
|
||
|
||
default:
|
||
return evaluate_subexp (NULL_TYPE, exp, pos, noside);
|
||
}
|
||
}
|
||
|
||
/* Evaluate a subexpression of EXP, at index *POS,
|
||
and return a value for the size of that subexpression.
|
||
Advance *POS over the subexpression. */
|
||
|
||
static value
|
||
evaluate_subexp_for_sizeof (exp, pos)
|
||
register struct expression *exp;
|
||
register int *pos;
|
||
{
|
||
enum exp_opcode op;
|
||
register int pc;
|
||
value val;
|
||
|
||
pc = (*pos);
|
||
op = exp->elts[pc].opcode;
|
||
|
||
switch (op)
|
||
{
|
||
/* This case is handled specially
|
||
so that we avoid creating a value for the result type.
|
||
If the result type is very big, it's desirable not to
|
||
create a value unnecessarily. */
|
||
case UNOP_IND:
|
||
(*pos)++;
|
||
val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
|
||
return value_from_longest (builtin_type_int, (LONGEST)
|
||
TYPE_LENGTH (TYPE_TARGET_TYPE (VALUE_TYPE (val))));
|
||
|
||
case UNOP_MEMVAL:
|
||
(*pos) += 3;
|
||
return value_from_longest (builtin_type_int,
|
||
(LONGEST) TYPE_LENGTH (exp->elts[pc + 1].type));
|
||
|
||
case OP_VAR_VALUE:
|
||
(*pos) += 4;
|
||
return
|
||
value_from_longest
|
||
(builtin_type_int,
|
||
(LONGEST) TYPE_LENGTH (SYMBOL_TYPE (exp->elts[pc + 2].symbol)));
|
||
|
||
default:
|
||
val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
|
||
return value_from_longest (builtin_type_int,
|
||
(LONGEST) TYPE_LENGTH (VALUE_TYPE (val)));
|
||
}
|
||
}
|
||
|
||
/* Parse a type expression in the string [P..P+LENGTH). */
|
||
|
||
struct type *
|
||
parse_and_eval_type (p, length)
|
||
char *p;
|
||
int length;
|
||
{
|
||
char *tmp = (char *)alloca (length + 4);
|
||
struct expression *expr;
|
||
tmp[0] = '(';
|
||
memcpy (tmp+1, p, length);
|
||
tmp[length+1] = ')';
|
||
tmp[length+2] = '0';
|
||
tmp[length+3] = '\0';
|
||
expr = parse_expression (tmp);
|
||
if (expr->elts[0].opcode != UNOP_CAST)
|
||
error ("Internal error in eval_type.");
|
||
return expr->elts[1].type;
|
||
}
|