635 lines
14 KiB
C
635 lines
14 KiB
C
/* Parse expressions for GDB.
|
||
Copyright (C) 1986, 1989, 1990, 1991 Free Software Foundation, Inc.
|
||
Modified from expread.y by the Department of Computer Science at the
|
||
State University of New York at Buffalo, 1991.
|
||
|
||
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
|
||
|
||
/* Parse an expression from text in a string,
|
||
and return the result as a struct expression pointer.
|
||
That structure contains arithmetic operations in reverse polish,
|
||
with constants represented by operations that are followed by special data.
|
||
See expression.h for the details of the format.
|
||
What is important here is that it can be built up sequentially
|
||
during the process of parsing; the lower levels of the tree always
|
||
come first in the result. */
|
||
|
||
#include "defs.h"
|
||
#include "symtab.h"
|
||
#include "gdbtypes.h"
|
||
#include "frame.h"
|
||
#include "expression.h"
|
||
#include "value.h"
|
||
#include "command.h"
|
||
#include "language.h"
|
||
#include "parser-defs.h"
|
||
|
||
static void
|
||
prefixify_expression PARAMS ((struct expression *));
|
||
|
||
static int
|
||
length_of_subexp PARAMS ((struct expression *, int));
|
||
|
||
static void
|
||
prefixify_subexp PARAMS ((struct expression *, struct expression *, int, int));
|
||
|
||
/* Assign machine-independent names to certain registers
|
||
(unless overridden by the REGISTER_NAMES table) */
|
||
|
||
struct std_regs std_regs[] = {
|
||
#ifdef PC_REGNUM
|
||
{ "pc", PC_REGNUM },
|
||
#endif
|
||
#ifdef FP_REGNUM
|
||
{ "fp", FP_REGNUM },
|
||
#endif
|
||
#ifdef SP_REGNUM
|
||
{ "sp", SP_REGNUM },
|
||
#endif
|
||
#ifdef PS_REGNUM
|
||
{ "ps", PS_REGNUM },
|
||
#endif
|
||
};
|
||
|
||
unsigned num_std_regs = (sizeof std_regs / sizeof std_regs[0]);
|
||
|
||
|
||
/* Begin counting arguments for a function call,
|
||
saving the data about any containing call. */
|
||
|
||
void
|
||
start_arglist ()
|
||
{
|
||
register struct funcall *new = (struct funcall *) xmalloc (sizeof (struct funcall));
|
||
|
||
new->next = funcall_chain;
|
||
new->arglist_len = arglist_len;
|
||
arglist_len = 0;
|
||
funcall_chain = new;
|
||
}
|
||
|
||
/* Return the number of arguments in a function call just terminated,
|
||
and restore the data for the containing function call. */
|
||
|
||
int
|
||
end_arglist ()
|
||
{
|
||
register int val = arglist_len;
|
||
register struct funcall *call = funcall_chain;
|
||
funcall_chain = call->next;
|
||
arglist_len = call->arglist_len;
|
||
free ((PTR)call);
|
||
return val;
|
||
}
|
||
|
||
/* Free everything in the funcall chain.
|
||
Used when there is an error inside parsing. */
|
||
|
||
void
|
||
free_funcalls ()
|
||
{
|
||
register struct funcall *call, *next;
|
||
|
||
for (call = funcall_chain; call; call = next)
|
||
{
|
||
next = call->next;
|
||
free ((PTR)call);
|
||
}
|
||
}
|
||
|
||
/* This page contains the functions for adding data to the struct expression
|
||
being constructed. */
|
||
|
||
/* Add one element to the end of the expression. */
|
||
|
||
/* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
|
||
a register through here */
|
||
|
||
void
|
||
write_exp_elt (expelt)
|
||
union exp_element expelt;
|
||
{
|
||
if (expout_ptr >= expout_size)
|
||
{
|
||
expout_size *= 2;
|
||
expout = (struct expression *) xrealloc ((char *) expout,
|
||
sizeof (struct expression)
|
||
+ expout_size * sizeof (union exp_element));
|
||
}
|
||
expout->elts[expout_ptr++] = expelt;
|
||
}
|
||
|
||
void
|
||
write_exp_elt_opcode (expelt)
|
||
enum exp_opcode expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.opcode = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
void
|
||
write_exp_elt_sym (expelt)
|
||
struct symbol *expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.symbol = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
void
|
||
write_exp_elt_longcst (expelt)
|
||
LONGEST expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.longconst = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
void
|
||
write_exp_elt_dblcst (expelt)
|
||
double expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.doubleconst = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
void
|
||
write_exp_elt_type (expelt)
|
||
struct type *expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.type = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
void
|
||
write_exp_elt_intern (expelt)
|
||
struct internalvar *expelt;
|
||
{
|
||
union exp_element tmp;
|
||
|
||
tmp.internalvar = expelt;
|
||
|
||
write_exp_elt (tmp);
|
||
}
|
||
|
||
/* Add a string constant to the end of the expression.
|
||
Follow it by its length in bytes, as a separate exp_element. */
|
||
|
||
void
|
||
write_exp_string (str)
|
||
struct stoken str;
|
||
{
|
||
register int len = str.length;
|
||
register int lenelt
|
||
= (len + sizeof (union exp_element)) / sizeof (union exp_element);
|
||
|
||
expout_ptr += lenelt;
|
||
|
||
if (expout_ptr >= expout_size)
|
||
{
|
||
expout_size = max (expout_size * 2, expout_ptr + 10);
|
||
expout = (struct expression *)
|
||
xrealloc ((char *) expout, (sizeof (struct expression)
|
||
+ (expout_size * sizeof (union exp_element))));
|
||
}
|
||
bcopy (str.ptr, (char *) &expout->elts[expout_ptr - lenelt], len);
|
||
((char *) &expout->elts[expout_ptr - lenelt])[len] = 0;
|
||
write_exp_elt_longcst ((LONGEST) len);
|
||
}
|
||
|
||
/* Return a null-terminated temporary copy of the name
|
||
of a string token. */
|
||
|
||
char *
|
||
copy_name (token)
|
||
struct stoken token;
|
||
{
|
||
bcopy (token.ptr, namecopy, token.length);
|
||
namecopy[token.length] = 0;
|
||
return namecopy;
|
||
}
|
||
|
||
/* Reverse an expression from suffix form (in which it is constructed)
|
||
to prefix form (in which we can conveniently print or execute it). */
|
||
|
||
static void
|
||
prefixify_expression (expr)
|
||
register struct expression *expr;
|
||
{
|
||
register int len = sizeof (struct expression) +
|
||
expr->nelts * sizeof (union exp_element);
|
||
register struct expression *temp;
|
||
register int inpos = expr->nelts, outpos = 0;
|
||
|
||
temp = (struct expression *) alloca (len);
|
||
|
||
/* Copy the original expression into temp. */
|
||
bcopy (expr, temp, len);
|
||
|
||
prefixify_subexp (temp, expr, inpos, outpos);
|
||
}
|
||
|
||
/* Return the number of exp_elements in the subexpression of EXPR
|
||
whose last exp_element is at index ENDPOS - 1 in EXPR. */
|
||
|
||
static int
|
||
length_of_subexp (expr, endpos)
|
||
register struct expression *expr;
|
||
register int endpos;
|
||
{
|
||
register int oplen = 1;
|
||
register int args = 0;
|
||
register int i;
|
||
|
||
if (endpos < 0)
|
||
error ("?error in length_of_subexp");
|
||
|
||
i = (int) expr->elts[endpos - 1].opcode;
|
||
|
||
switch (i)
|
||
{
|
||
/* C++ */
|
||
case OP_SCOPE:
|
||
oplen = 4 + ((expr->elts[endpos - 2].longconst
|
||
+ sizeof (union exp_element))
|
||
/ sizeof (union exp_element));
|
||
break;
|
||
|
||
case OP_LONG:
|
||
case OP_DOUBLE:
|
||
oplen = 4;
|
||
break;
|
||
|
||
case OP_TYPE:
|
||
case OP_BOOL:
|
||
case OP_VAR_VALUE:
|
||
case OP_LAST:
|
||
case OP_REGISTER:
|
||
case OP_INTERNALVAR:
|
||
oplen = 3;
|
||
break;
|
||
|
||
case OP_FUNCALL:
|
||
oplen = 3;
|
||
args = 1 + expr->elts[endpos - 2].longconst;
|
||
break;
|
||
|
||
case UNOP_MAX:
|
||
case UNOP_MIN:
|
||
oplen = 3;
|
||
args = 0;
|
||
break;
|
||
|
||
case BINOP_VAL:
|
||
case UNOP_CAST:
|
||
case UNOP_MEMVAL:
|
||
oplen = 3;
|
||
args = 1;
|
||
break;
|
||
|
||
case UNOP_ABS:
|
||
case UNOP_CAP:
|
||
case UNOP_CHR:
|
||
case UNOP_FLOAT:
|
||
case UNOP_HIGH:
|
||
case UNOP_ODD:
|
||
case UNOP_ORD:
|
||
case UNOP_TRUNC:
|
||
oplen = 1;
|
||
args = 1;
|
||
break;
|
||
|
||
case STRUCTOP_STRUCT:
|
||
case STRUCTOP_PTR:
|
||
args = 1;
|
||
case OP_M2_STRING:
|
||
case OP_STRING:
|
||
oplen = 3 + ((expr->elts[endpos - 2].longconst
|
||
+ sizeof (union exp_element))
|
||
/ sizeof (union exp_element));
|
||
break;
|
||
|
||
case TERNOP_COND:
|
||
args = 3;
|
||
break;
|
||
|
||
/* Modula-2 */
|
||
case BINOP_MULTI_SUBSCRIPT:
|
||
oplen=3;
|
||
args = 1 + expr->elts[endpos- 2].longconst;
|
||
break;
|
||
|
||
case BINOP_ASSIGN_MODIFY:
|
||
oplen = 3;
|
||
args = 2;
|
||
break;
|
||
|
||
/* C++ */
|
||
case OP_THIS:
|
||
oplen = 2;
|
||
break;
|
||
|
||
default:
|
||
args = 1 + (i < (int) BINOP_END);
|
||
}
|
||
|
||
while (args > 0)
|
||
{
|
||
oplen += length_of_subexp (expr, endpos - oplen);
|
||
args--;
|
||
}
|
||
|
||
return oplen;
|
||
}
|
||
|
||
/* Copy the subexpression ending just before index INEND in INEXPR
|
||
into OUTEXPR, starting at index OUTBEG.
|
||
In the process, convert it from suffix to prefix form. */
|
||
|
||
static void
|
||
prefixify_subexp (inexpr, outexpr, inend, outbeg)
|
||
register struct expression *inexpr;
|
||
struct expression *outexpr;
|
||
register int inend;
|
||
int outbeg;
|
||
{
|
||
register int oplen = 1;
|
||
register int args = 0;
|
||
register int i;
|
||
int *arglens;
|
||
enum exp_opcode opcode;
|
||
|
||
/* Compute how long the last operation is (in OPLEN),
|
||
and also how many preceding subexpressions serve as
|
||
arguments for it (in ARGS). */
|
||
|
||
opcode = inexpr->elts[inend - 1].opcode;
|
||
switch (opcode)
|
||
{
|
||
/* C++ */
|
||
case OP_SCOPE:
|
||
oplen = 4 + ((inexpr->elts[inend - 2].longconst
|
||
+ sizeof (union exp_element))
|
||
/ sizeof (union exp_element));
|
||
break;
|
||
|
||
case OP_LONG:
|
||
case OP_DOUBLE:
|
||
oplen = 4;
|
||
break;
|
||
|
||
case OP_TYPE:
|
||
case OP_BOOL:
|
||
case OP_VAR_VALUE:
|
||
case OP_LAST:
|
||
case OP_REGISTER:
|
||
case OP_INTERNALVAR:
|
||
oplen = 3;
|
||
break;
|
||
|
||
case OP_FUNCALL:
|
||
oplen = 3;
|
||
args = 1 + inexpr->elts[inend - 2].longconst;
|
||
break;
|
||
|
||
case UNOP_MIN:
|
||
case UNOP_MAX:
|
||
oplen = 3;
|
||
args = 0;
|
||
break;
|
||
|
||
case UNOP_CAST:
|
||
case UNOP_MEMVAL:
|
||
oplen = 3;
|
||
args = 1;
|
||
break;
|
||
|
||
case UNOP_ABS:
|
||
case UNOP_CAP:
|
||
case UNOP_CHR:
|
||
case UNOP_FLOAT:
|
||
case UNOP_HIGH:
|
||
case UNOP_ODD:
|
||
case UNOP_ORD:
|
||
case UNOP_TRUNC:
|
||
oplen=1;
|
||
args=1;
|
||
break;
|
||
|
||
case STRUCTOP_STRUCT:
|
||
case STRUCTOP_PTR:
|
||
args = 1;
|
||
case OP_M2_STRING:
|
||
case OP_STRING:
|
||
oplen = 3 + ((inexpr->elts[inend - 2].longconst
|
||
+ sizeof (union exp_element))
|
||
/ sizeof (union exp_element));
|
||
|
||
break;
|
||
|
||
case TERNOP_COND:
|
||
args = 3;
|
||
break;
|
||
|
||
case BINOP_ASSIGN_MODIFY:
|
||
oplen = 3;
|
||
args = 2;
|
||
break;
|
||
|
||
/* Modula-2 */
|
||
case BINOP_MULTI_SUBSCRIPT:
|
||
oplen=3;
|
||
args = 1 + inexpr->elts[inend - 2].longconst;
|
||
break;
|
||
|
||
/* C++ */
|
||
case OP_THIS:
|
||
oplen = 2;
|
||
break;
|
||
|
||
default:
|
||
args = 1 + ((int) opcode < (int) BINOP_END);
|
||
}
|
||
|
||
/* Copy the final operator itself, from the end of the input
|
||
to the beginning of the output. */
|
||
inend -= oplen;
|
||
bcopy (&inexpr->elts[inend], &outexpr->elts[outbeg],
|
||
oplen * sizeof (union exp_element));
|
||
outbeg += oplen;
|
||
|
||
/* Find the lengths of the arg subexpressions. */
|
||
arglens = (int *) alloca (args * sizeof (int));
|
||
for (i = args - 1; i >= 0; i--)
|
||
{
|
||
oplen = length_of_subexp (inexpr, inend);
|
||
arglens[i] = oplen;
|
||
inend -= oplen;
|
||
}
|
||
|
||
/* Now copy each subexpression, preserving the order of
|
||
the subexpressions, but prefixifying each one.
|
||
In this loop, inend starts at the beginning of
|
||
the expression this level is working on
|
||
and marches forward over the arguments.
|
||
outbeg does similarly in the output. */
|
||
for (i = 0; i < args; i++)
|
||
{
|
||
oplen = arglens[i];
|
||
inend += oplen;
|
||
prefixify_subexp (inexpr, outexpr, inend, outbeg);
|
||
outbeg += oplen;
|
||
}
|
||
}
|
||
|
||
/* This page contains the two entry points to this file. */
|
||
|
||
/* Read an expression from the string *STRINGPTR points to,
|
||
parse it, and return a pointer to a struct expression that we malloc.
|
||
Use block BLOCK as the lexical context for variable names;
|
||
if BLOCK is zero, use the block of the selected stack frame.
|
||
Meanwhile, advance *STRINGPTR to point after the expression,
|
||
at the first nonwhite character that is not part of the expression
|
||
(possibly a null character).
|
||
|
||
If COMMA is nonzero, stop if a comma is reached. */
|
||
|
||
struct expression *
|
||
parse_exp_1 (stringptr, block, comma)
|
||
char **stringptr;
|
||
struct block *block;
|
||
int comma;
|
||
{
|
||
struct cleanup *old_chain;
|
||
|
||
lexptr = *stringptr;
|
||
|
||
paren_depth = 0;
|
||
type_stack_depth = 0;
|
||
|
||
comma_terminates = comma;
|
||
|
||
if (lexptr == 0 || *lexptr == 0)
|
||
error_no_arg ("expression to compute");
|
||
|
||
old_chain = make_cleanup (free_funcalls, 0);
|
||
funcall_chain = 0;
|
||
|
||
expression_context_block = block ? block : get_selected_block ();
|
||
|
||
namecopy = (char *) alloca (strlen (lexptr) + 1);
|
||
expout_size = 10;
|
||
expout_ptr = 0;
|
||
expout = (struct expression *)
|
||
xmalloc (sizeof (struct expression)
|
||
+ expout_size * sizeof (union exp_element));
|
||
expout->language_defn = current_language;
|
||
make_cleanup (free_current_contents, &expout);
|
||
|
||
if (current_language->la_parser ())
|
||
current_language->la_error (NULL);
|
||
|
||
discard_cleanups (old_chain);
|
||
expout->nelts = expout_ptr;
|
||
expout = (struct expression *)
|
||
xrealloc ((char *) expout,
|
||
sizeof (struct expression)
|
||
+ expout_ptr * sizeof (union exp_element));
|
||
prefixify_expression (expout);
|
||
*stringptr = lexptr;
|
||
return expout;
|
||
}
|
||
|
||
/* Parse STRING as an expression, and complain if this fails
|
||
to use up all of the contents of STRING. */
|
||
|
||
struct expression *
|
||
parse_expression (string)
|
||
char *string;
|
||
{
|
||
register struct expression *exp;
|
||
exp = parse_exp_1 (&string, 0, 0);
|
||
if (*string)
|
||
error ("Junk after end of expression.");
|
||
return exp;
|
||
}
|
||
|
||
void
|
||
push_type (tp)
|
||
enum type_pieces tp;
|
||
{
|
||
if (type_stack_depth == type_stack_size)
|
||
{
|
||
type_stack_size *= 2;
|
||
type_stack = (union type_stack_elt *)
|
||
xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
|
||
}
|
||
type_stack[type_stack_depth++].piece = tp;
|
||
}
|
||
|
||
void
|
||
push_type_int (n)
|
||
int n;
|
||
{
|
||
if (type_stack_depth == type_stack_size)
|
||
{
|
||
type_stack_size *= 2;
|
||
type_stack = (union type_stack_elt *)
|
||
xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
|
||
}
|
||
type_stack[type_stack_depth++].int_val = n;
|
||
}
|
||
|
||
enum type_pieces
|
||
pop_type ()
|
||
{
|
||
if (type_stack_depth)
|
||
return type_stack[--type_stack_depth].piece;
|
||
return tp_end;
|
||
}
|
||
|
||
int
|
||
pop_type_int ()
|
||
{
|
||
if (type_stack_depth)
|
||
return type_stack[--type_stack_depth].int_val;
|
||
/* "Can't happen". */
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
_initialize_parse ()
|
||
{
|
||
type_stack_size = 80;
|
||
type_stack_depth = 0;
|
||
type_stack = (union type_stack_elt *)
|
||
xmalloc (type_stack_size * sizeof (*type_stack));
|
||
}
|