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fcall.c
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fcall.c
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/********************************************
fcall.c
copyright 1991,2014-2016 Michael D. Brennan
This is a source file for mawk, an implementation of
the AWK programming language.
Mawk is distributed without warranty under the terms of
the GNU General Public License, version 3, 2007.
If you import elements of this code into another product,
you agree to not name that product mawk.
********************************************/
#include "mawk.h"
#include "table.h"
#include "code.h"
/* This file has functions involved with type checking of
function calls
*/
static FCALL_REC * first_pass( FCALL_REC * );
static CA_REC * call_arg_check( FBLOCK *, CA_REC *, INST *, unsigned );
static int arg_cnt_ok( FBLOCK *, CA_REC *, unsigned );
static void relocate_arglist( CA_REC *, int, unsigned, int );
static int check_progress;
/* flag that indicates call_arg_check() was able to type
check some call arguments */
/* type checks a list of call arguments,
returns a list of arguments whose type is still unknown
*/
static CA_REC *
call_arg_check(
FBLOCK * callee,
CA_REC * entry_list,
INST * start, /* to locate patch */
unsigned line_no ) /* for error messages */
{
register CA_REC * q;
CA_REC * exit_list = (CA_REC *)0;
check_progress = 0;
/* loop :
take q off entry_list
test it
if OK zfree(q) else put on exit_list */
while ( ( q = entry_list ) ) {
entry_list = q->link;
if ( q->type == ST_NONE ) {
/* try to infer the type */
/* it might now be in symbol table */
if ( q->sym_p->type == ST_VAR ) {
/* set type and patch */
q->type = CA_EXPR;
start[q->call_offset + 1].ptr = (void *)q->sym_p->stval.cp;
}
else if ( q->sym_p->type == ST_ARRAY ) {
q->type = CA_ARRAY;
start[q->call_offset].op = A_PUSHA;
start[q->call_offset + 1].ptr = (void *)q->sym_p->stval.array;
}
else /* try to infer from callee */
{
switch ( callee->typev[q->arg_num] ) {
case ST_LOCAL_VAR:
q->type = CA_EXPR;
q->sym_p->type = ST_VAR;
q->sym_p->stval.cp = ZMALLOC( CELL );
q->sym_p->stval.cp->type = C_NOINIT;
start[q->call_offset + 1].ptr = (void *)q->sym_p->stval.cp;
break;
case ST_LOCAL_ARRAY:
q->type = CA_ARRAY;
q->sym_p->type = ST_ARRAY;
q->sym_p->stval.array = new_ARRAY();
start[q->call_offset].op = A_PUSHA;
start[q->call_offset + 1].ptr = (void *)q->sym_p->stval.array;
break;
}
}
}
else if ( q->type == ST_LOCAL_NONE ) {
/* try to infer the type */
if ( *q->type_p == ST_LOCAL_VAR ) {
/* set type , don't need to patch */
q->type = CA_EXPR;
}
else if ( *q->type_p == ST_LOCAL_ARRAY ) {
q->type = CA_ARRAY;
start[q->call_offset].op = LA_PUSHA;
/* offset+1 op is OK */
}
else /* try to infer from callee */
{
switch ( callee->typev[q->arg_num] ) {
case ST_LOCAL_VAR:
q->type = CA_EXPR;
*q->type_p = ST_LOCAL_VAR;
/* do not need to patch */
break;
case ST_LOCAL_ARRAY:
q->type = CA_ARRAY;
*q->type_p = ST_LOCAL_ARRAY;
start[q->call_offset].op = LA_PUSHA;
break;
}
}
}
/* if we still do not know the type put on the new list
else type check */
if ( q->type == ST_NONE || q->type == ST_LOCAL_NONE ) {
q->link = exit_list;
exit_list = q;
}
else /* type known */
{
if ( callee->typev[q->arg_num] == ST_LOCAL_NONE ) {
callee->typev[q->arg_num] = q->type;
}
else if ( q->type != callee->typev[q->arg_num] ) {
call_error( line_no, "type error in arg(%d) in call to %s",
q->arg_num + 1, callee->name );
}
ZFREE( q );
check_progress = 1;
}
} /* while */
return exit_list;
}
static int
arg_cnt_ok(
FBLOCK * fbp,
CA_REC * q,
unsigned line_no )
{
if ( (int)q->arg_num >= (int)fbp->nargs )
/* casts shutup stupid warning from solaris sun cc */
{
call_error( line_no, "too many arguments in call to %s", fbp->name );
return 0;
}
else
return 1;
}
FCALL_REC * resolve_list;
/* function calls whose arg types need checking
are stored on this list */
/* on first pass thru the resolve list
we check :
if forward referenced functions were really defined
if right number of arguments
and compute call_start which is now known
*/
static FCALL_REC *
first_pass( FCALL_REC * p )
{
FCALL_REC dummy;
register FCALL_REC * q = &dummy; /* trails p */
q->link = p;
while ( p ) {
if ( !p->callee->code ) {
/* callee never defined */
compile_error( "function %s never defined", p->callee->name );
/* delete p from list */
q->link = p->link;
/* don't worry about freeing memory, we'll exit soon */
}
/* note p->arg_list starts with last argument */
else if ( !p->arg_list /* nothing to do */ || ( !p->arg_cnt_checked && !arg_cnt_ok( p->callee, p->arg_list, p->line_no ) ) ) {
q->link = p->link; /* delete p */
/* the ! arg_list case is not an error so free memory */
ZFREE( p );
}
else {
/* keep p and set call_start */
q = p;
switch ( p->call_scope ) {
case SCOPE_MAIN:
p->call_start = main_start;
break;
case SCOPE_BEGIN:
p->call_start = begin_start;
break;
case SCOPE_END:
p->call_start = end_start;
break;
case SCOPE_FUNCT:
p->call_start = p->call->code;
break;
}
}
p = q->link;
}
return dummy.link;
}
/* continuously walk the resolve_list making type deductions
until this list goes empty or no more progress can be made
(An example where no more progress can be made is at end of file
*/
void
resolve_fcalls( void )
{
register FCALL_REC *p, *old_list, *new_list;
int progress; /* a flag */
old_list = first_pass( resolve_list );
new_list = (FCALL_REC *)0;
progress = 0;
while ( 1 ) {
if ( !old_list ) {
/* flop the lists */
old_list = new_list;
if ( !old_list /* nothing left */
|| !progress /* can't do any more */ )
return;
new_list = (FCALL_REC *)0;
progress = 0;
}
p = old_list;
old_list = p->link;
if ( ( p->arg_list = call_arg_check( p->callee, p->arg_list,
p->call_start, p->line_no ) ) ) {
/* still have work to do , put on new_list */
progress |= check_progress;
p->link = new_list;
new_list = p;
}
else {
/* done with p */
progress = 1;
ZFREE( p );
}
}
}
/* the parser has just reduced a function call ;
the info needed to type check is passed in. If type checking
can not be done yet (most common reason -- function referenced
but not defined), a node is added to the resolve list.
*/
void
check_fcall(
FBLOCK * callee,
int call_scope,
int move_level,
FBLOCK * call,
CA_REC * arg_list,
unsigned line_no )
{
FCALL_REC * p;
if ( !callee->code ) {
/* forward reference to a function to be defined later */
p = ZMALLOC( FCALL_REC );
p->callee = callee;
p->call_scope = call_scope;
p->move_level = move_level;
p->call = call;
p->arg_list = arg_list;
p->arg_cnt_checked = 0;
p->line_no = line_no;
/* add to resolve list */
p->link = resolve_list;
resolve_list = p;
}
else if ( arg_list && arg_cnt_ok( callee, arg_list, line_no ) ) {
/* usually arg_list disappears here and all is well
otherwise add to resolve list */
if ( ( arg_list = call_arg_check( callee, arg_list,
code_base, line_no ) ) ) {
p = ZMALLOC( FCALL_REC );
p->callee = callee;
p->call_scope = call_scope;
p->move_level = move_level;
p->call = call;
p->arg_list = arg_list;
p->arg_cnt_checked = 1;
p->line_no = line_no;
/* add to resolve list */
p->link = resolve_list;
resolve_list = p;
}
}
}
/* code_pop() has just moved some code. If this code contains
a function call, it might need to be relocated on the
resolve list too. This function does it.
*/
void
relocate_resolve_list(
int scope,
int move_level,
FBLOCK * fbp,
int orig_offset,
unsigned len,
int delta ) /* relocation distance */
{
FCALL_REC * p = resolve_list;
while ( p ) {
if ( scope == p->call_scope && move_level == p->move_level && ( scope == SCOPE_FUNCT ? fbp == p->call : 1 ) ) {
relocate_arglist( p->arg_list, orig_offset,
len, delta );
}
p = p->link;
}
}
static void
relocate_arglist(
CA_REC * arg_list,
int offset,
unsigned len,
int delta )
{
register CA_REC * p;
if ( !arg_list )
return;
p = arg_list;
/* all nodes must be relocated or none, so test the
first one */
/* Note: call_offset is always set even for args that don't need to
be patched so that this check works. */
if ( p->call_offset < offset || p->call_offset >= offset + len )
return;
/* relocate the whole list */
do {
p->call_offset += delta;
p = p->link;
} while ( p );
}
/* example where typing cannot progress
{ f(z) }
function f(x) { print NR }
# this is legal, does something useful, but absurdly written
# We have to design so this works
*/