* parse.c: New file with the common code remains of expread.y.

* expread.y, expread.tab.c:  Remove.
* parser-defs.h:  New file with common declarations from expread.y.
* c-exp.y:  New file with the C parser from expread.y.
* m2-exp.y:  New file with the Modula-2 parser.
This commit is contained in:
John Gilmore 1991-09-19 10:31:00 +00:00
parent 997a978c5d
commit 3d6b6a9075
4 changed files with 3518 additions and 0 deletions

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/* 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 <stdio.h>
#include "defs.h"
#include "param.h"
#include "symtab.h"
#include "frame.h"
#include "expression.h"
#include "value.h"
#include "command.h"
#include "language.h"
#include "parser-defs.h"
/* 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 (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 (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 (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 (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_subexp ();
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. */
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 (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 (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 (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));
}

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/* Parser definitions 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.
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. */
struct std_regs {
char *name;
int regnum;
};
extern struct std_regs std_regs[];
extern unsigned num_std_regs;
struct expression *expout;
int expout_size;
int expout_ptr;
extern struct type *init_type ();
void write_exp_elt ();
void write_exp_elt_opcode ();
void write_exp_elt_sym ();
void write_exp_elt_longcst ();
void write_exp_elt_dblcst ();
void write_exp_elt_type ();
void write_exp_elt_intern ();
void write_exp_string ();
void start_arglist ();
int end_arglist ();
void free_funcalls ();
char *copy_name ();
/* If this is nonzero, this block is used as the lexical context
for symbol names. */
struct block *expression_context_block;
/* The innermost context required by the stack and register variables
we've encountered so far. */
struct block *innermost_block;
/* The block in which the most recently discovered symbol was found. */
struct block *block_found;
/* Number of arguments seen so far in innermost function call. */
int arglist_len;
/* Data structure for saving values of arglist_len
for function calls whose arguments contain other function calls. */
struct funcall
{
struct funcall *next;
int arglist_len;
};
struct funcall *funcall_chain;
/* This kind of datum is used to represent the name
of a symbol token. */
struct stoken
{
char *ptr;
int length;
};
struct ttype
{
struct stoken stoken;
struct type *type;
};
struct symtoken
{
struct stoken stoken;
struct symbol *sym;
int is_a_field_of_this;
};
/* For parsing of complicated types.
An array should be preceded in the list by the size of the array. */
enum type_pieces
{tp_end = -1, tp_pointer, tp_reference, tp_array, tp_function};
/* The stack can contain either an enum type_pieces or an int. */
union type_stack_elt {
enum type_pieces piece;
int int_val;
};
union type_stack_elt *type_stack;
int type_stack_depth, type_stack_size;
void push_type ();
void push_type_int ();
enum type_pieces pop_type ();
int pop_type_int ();
/* During parsing of a C expression, the pointer to the next character
is in this variable. */
char *lexptr;
/* Tokens that refer to names do so with explicit pointer and length,
so they can share the storage that lexptr is parsing.
When it is necessary to pass a name to a function that expects
a null-terminated string, the substring is copied out
into a block of storage that namecopy points to.
namecopy is allocated once, guaranteed big enough, for each parsing. */
char *namecopy;
/* Current depth in parentheses within the expression. */
int paren_depth;
/* Nonzero means stop parsing on first comma (if not within parentheses). */
int comma_terminates;
/* These codes indicate operator precedences for expression printing,
least tightly binding first. */
/* Adding 1 to a precedence value is done for binary operators,
on the operand which is more tightly bound, so that operators
of equal precedence within that operand will get parentheses. */
/* PREC_HYPER and PREC_ABOVE_COMMA are not the precedence of any operator;
they are used as the "surrounding precedence" to force
various kinds of things to be parenthesized. */
enum precedence
{ PREC_NULL, PREC_COMMA, PREC_ABOVE_COMMA, PREC_ASSIGN, PREC_OR, PREC_AND,
PREC_LOGIOR, PREC_LOGAND, PREC_LOGXOR, PREC_EQUAL, PREC_ORDER,
PREC_SHIFT, PREC_ADD, PREC_MUL, PREC_REPEAT,
PREC_HYPER, PREC_PREFIX, PREC_SUFFIX };
/* Table mapping opcodes into strings for printing operators
and precedences of the operators. */
struct op_print
{
char *string;
enum exp_opcode opcode;
/* Precedence of operator. These values are used only by comparisons. */
enum precedence precedence;
int right_assoc;
};