quakeforge/tools/qfcc/source/dags.c
Bill Currie db605fa998 Improve the type accuracy of dag_gencode.
Surprisingly, I don't yet have to "throw one out", but things are still
problematic: rcall1 is getting two arguments, goto and return get lost,
rcall2 got an old temp rather than the value it was supposed to, but
progress :)
2012-11-15 17:58:33 +09:00

524 lines
11 KiB
C

/*
dags.c
DAG representation of basic blocks
Copyright (C) 2012 Bill Currie <bill@taniwha.org>
Author: Bill Currie <bill@taniwha.org>
Date: 2012/05/08
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:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif
#include <stdlib.h>
#include "QF/dstring.h"
#include "QF/mathlib.h"
#include "dags.h"
#include "diagnostic.h"
#include "flow.h"
#include "qfcc.h"
#include "set.h"
#include "statements.h"
#include "strpool.h"
#include "symtab.h"
static daglabel_t *free_labels;
static dagnode_t *free_nodes;
static daglabel_t *daglabel_chain;
static void
flush_daglabels (void)
{
while (daglabel_chain) {
operand_t *op;
if ((op = daglabel_chain->op)) {
while (op->op_type == op_alias)
op = op->o.alias;
if (op->op_type == op_symbol)
op->o.symbol->daglabel = 0;
else if (op->op_type == op_temp)
op->o.tempop.daglabel = 0;
else if (op->op_type == op_value || op->op_type == op_pointer)
op->o.value->daglabel = 0;
else
internal_error (0, "unexpected operand type");
}
daglabel_chain = daglabel_chain->daglabel_chain;
}
}
static daglabel_t *
new_label (void)
{
daglabel_t *label;
ALLOC (256, daglabel_t, labels, label);
label->daglabel_chain = daglabel_chain;
daglabel_chain = label;
return label;
}
static dagnode_t *
new_node (void)
{
dagnode_t *node;
ALLOC (256, dagnode_t, nodes, node);
return node;
}
const char *
daglabel_string (daglabel_t *label)
{
static dstring_t *str;
if ((label->opcode && label->op) || (!label->opcode && !label->op))
return "bad label";
if (label->opcode)
return label->opcode;
if (!str)
str = dstring_new ();
// operand_string might use quote_string, which returns a pointer to
// a static variable.
dstring_copystr (str, operand_string (label->op));
return quote_string (str->str);
}
static daglabel_t *
opcode_label (const char *opcode)
{
daglabel_t *label;
label = new_label ();
label->opcode = opcode;
return label;
}
static daglabel_t *
operand_label (operand_t *op)
{
symbol_t *sym = 0;
ex_value_t *val = 0;
daglabel_t *label;
if (!op)
return 0;
while (op->op_type == op_alias)
op = op->o.alias;
if (op->op_type == op_temp) {
if (op->o.tempop.daglabel)
return op->o.tempop.daglabel;
label = new_label ();
label->op = op;
op->o.tempop.daglabel = label;
} else if (op->op_type == op_symbol) {
sym = op->o.symbol;
if (sym->daglabel)
return sym->daglabel;
label = new_label ();
label->op = op;
sym->daglabel = label;
} else if (op->op_type == op_value || op->op_type == op_pointer) {
val = op->o.value;
if (val->daglabel)
return val->daglabel;
label = new_label ();
label->op = op;
val->daglabel = label;
} else {
internal_error (0, "unexpected operand type: %d", op->op_type);
}
return label;
}
static dagnode_t *
leaf_node (operand_t *op)
{
daglabel_t *label;
dagnode_t *node;
if (!op)
return 0;
node = new_node ();
node->tl = op->type;
label = operand_label (op);
label->dagnode = node;
node->label = label;
return node;
}
static dagnode_t *
node (operand_t *op)
{
symbol_t *sym;
if (!op)
return 0;
while (op->op_type == op_alias)
op = op->o.alias;
if (op->op_type == op_symbol) {
sym = op->o.symbol;
if (sym->sy_type == sy_const)
return 0;
if (sym->daglabel)
return sym->daglabel->dagnode;
} else if (op->op_type == op_temp) {
if (op->o.tempop.daglabel)
return op->o.tempop.daglabel->dagnode;
}
return 0;
}
static int
dagnode_match (const dagnode_t *n, const daglabel_t *op,
const dagnode_t *y, const dagnode_t *z, const dagnode_t *w)
{
if (n->label->opcode != op->opcode)
return 0;
if (n->a && y && n->a->label->op != y->label->op)
return 0;
if (n->b && z && n->b->label->op != z->label->op)
return 0;
if (n->c && w && n->c->label->op != w->label->op)
return 0;
if ((!n->a) ^ (!y))
return 0;
if ((!n->c) ^ (!z))
return 0;
if ((!n->b) ^ (!w))
return 0;
return 1;
}
static int
op_is_identifer (operand_t *op)
{
while (op->op_type == op_alias)
op = op->o.alias;
if (op->op_type == op_pointer)
return 1;
if (op->op_type == op_temp)
return 1;
if (op->op_type != op_symbol)
return 0;
if (op->o.symbol->sy_type != sy_var)
return 0;
return 1;
}
static void
dagnode_attach_label (dagnode_t *n, daglabel_t *l)
{
if (!l->op)
internal_error (0, "attempt to attach operator label to dagnode "
"identifers");
if (!op_is_identifer (l->op))
internal_error (0, "attempt to attach non-identifer label to dagnode "
"identifers");
if (n->identifiers)
n->identifiers->prev = &l->next;
l->next = n->identifiers;
l->prev = &n->identifiers;
l->dagnode = n;
n->identifiers = l;
}
static void
daglabel_detatch (daglabel_t *l)
{
if (l->next)
l->next->prev = l->prev;
*l->prev = l->next;
l->dagnode = 0;
}
static statement_t *
build_statement (const char *opcode, operand_t *a, operand_t *b, operand_t *c,
expr_t *expr)
{
if ((!a && (b || c)) || (a && !b && c))
internal_error (0, "invalid operand combo");
statement_t *st = new_statement (opcode, expr);
st->opa = a;
st->opb = b;
st->opc = c;
return st;
}
dagnode_t *
dag_create (const flownode_t *flownode)
{
sblock_t *block = flownode->sblock;
statement_t *s;
dagnode_t *dagnodes = 0;
dagnode_t **dagtail = &dagnodes;
dagnode_t *d;
flush_daglabels ();
for (s = block->statements; s; s = s->next) {
operand_t *x = 0, *y = 0, *z = 0, *w = 0;
dagnode_t *n = 0, *ny, *nz, *nw;
daglabel_t *op, *lx;
int simp;
simp = find_operands (s, &x, &y, &z, &w);
if (!(ny = node (y))) {
ny = leaf_node (y);
if (simp) {
*dagtail = ny;
dagtail = &ny->next;
}
}
if (!(nz = node (z)))
nz = leaf_node (z);
if (!(nw = node (w)))
nw = leaf_node (w);
op = opcode_label (s->opcode);
if (simp) {
n = ny;
} else {
for (n = dagnodes; n; n = n->next)
if (dagnode_match (n, op, ny, nz, nw))
break;
}
if (!n) {
n = new_node ();
n->statement = s;
n->label = op;
n->a = ny;
n->b = nz;
n->c = nw;
if (ny) {
ny->is_child = 1;
n->ta = y->type;
}
if (nz) {
nz->is_child = 1;
n->tb = z->type;
}
if (nw) {
nw->is_child = 1;
n->tc = w->type;
}
*dagtail = n;
dagtail = &n->next;
}
lx = operand_label (x);
if (lx) {
if (lx->prev)
daglabel_detatch (lx);
dagnode_attach_label (n, lx);
}
// c = a * b
// c = ~a
// c = a / b
// c = a + b
// c = a - b
// c = a {==,!=,<=,>=,<,>} b
// c = a.b
// c = &a.b
// c = a (convert)
// b = a
// b .= a
// b.c = a
// c = !a
// cond a goto b
// callN a
// rcallN a, [b, [c]]
// state a, b
// state a, b, c
// goto a
// jump a
// jumpb a, b
// c = a &&/|| b
// c = a <</>> b
// c = a & b
// c = a | b
// c = a % b
// c = a ^ b
// c = a (move) b (count)
}
for (d = dagnodes; d; d = d->next) {
daglabel_t **l = &d->identifiers;
while (*l) {
if ((*l)->op->op_type == op_temp
&& !set_is_member (flownode->live_vars.out,
flow_get_var ((*l)->op)->number))
daglabel_detatch (*l);
else
l = &(*l)->next;
}
}
while (dagnodes->is_child) {
dagnode_t *n = dagnodes->next;
dagnodes->next = 0;
dagnodes = n;
}
for (d = dagnodes; d && d->next; d = d->next) {
while (d->next && d->next->is_child) {
dagnode_t *n = d->next->next;
d->next->next = 0;
d->next = n;
}
}
return dagnodes;
}
static void
dag_calc_node_costs (dagnode_t *dagnode)
{
if ((!dagnode->a && (dagnode->b || dagnode->c))
|| (dagnode->a && !dagnode->b && dagnode->c))
internal_error (0, "bad dag node");
if (dagnode->a)
dag_calc_node_costs (dagnode->a);
if (dagnode->b)
dag_calc_node_costs (dagnode->b);
if (dagnode->c)
dag_calc_node_costs (dagnode->c);
// if dagnode->a is null, then this is a leaf (as b and c are guaranted to
// be null)
if (!dagnode->a) {
// Because qc vm statements don't mix source and destination operands,
// leaves never need temporary variables.
dagnode->cost = 0;
} else {
int different = 0;
// a non-leaf is guaranteed to have a valid "a"
dagnode->cost = dagnode->a->cost;
if (dagnode->b && dagnode->b->cost != dagnode->cost) {
dagnode->cost = max (dagnode->cost, dagnode->b->cost);
different = 1;
}
if (dagnode->c && (different || dagnode->c->cost != dagnode->cost)) {
dagnode->cost = max (dagnode->cost, dagnode->c->cost);
different = 1;
}
if (!different)
dagnode->cost += 1;
}
}
static operand_t *
fix_op_type (operand_t *op, etype_t type)
{
if (op && op->op_type != op_label && op->type != type)
op = alias_operand (op, type);
return op;
}
static operand_t *
dag_gencode (sblock_t *block, const dagnode_t *dagnode)
{
if (!dagnode->a) {
statement_t *st;
daglabel_t *var = 0;
operand_t *op = fix_op_type (dagnode->label->op, dagnode->tl);
if (dagnode->identifiers) {
var = dagnode->identifiers;
}
for (var = dagnode->identifiers; var; var = var->next) {
operand_t *vop = fix_op_type (var->op, op->type);
st = build_statement ("=", op, vop, 0, 0);
sblock_add_statement (block, st);
}
return op;
} else {
statement_t *st;
daglabel_t *var = 0;
operand_t *op_a = 0;
operand_t *op_b = 0;
operand_t *op_c = 0;
if (flow_is_cond (dagnode->statement))
op_b = dagnode->statement->opb;
if (dagnode->b && dagnode->c) {
op_a = dag_gencode (block, dagnode->a);
op_b = dag_gencode (block, dagnode->b);
op_c = dag_gencode (block, dagnode->c);
op_c = fix_op_type (op_c, dagnode->tc);
} else if (dagnode->b) {
if (dagnode->a->cost < dagnode->b->cost) {
op_b = dag_gencode (block, dagnode->b);
op_a = dag_gencode (block, dagnode->a);
} else {
op_a = dag_gencode (block, dagnode->a);
op_b = dag_gencode (block, dagnode->b);
}
} else {
op_a = dag_gencode (block, dagnode->a);
}
if (op_a && op_b && get_type (dagnode->statement->expr)) {
if (dagnode->identifiers) {
op_c = dagnode->identifiers->op;
var = dagnode->identifiers->next;
op_c = fix_op_type (op_c,
extract_type (dagnode->statement->expr));
} else {
op_c = temp_operand (get_type (dagnode->statement->expr));
}
}
op_a = fix_op_type (op_a, dagnode->ta);
op_b = fix_op_type (op_b, dagnode->tb);
st = build_statement (dagnode->label->opcode, op_a, op_b, op_c,
dagnode->statement->expr);
sblock_add_statement (block, st);
while (var) {
operand_t *vop = fix_op_type (var->op, op_c->type);
st = build_statement ("=", op_c, vop, 0, 0);
sblock_add_statement (block, st);
var = var->next;
}
return op_c;
}
return 0;
}
void
dag_generate (sblock_t *block, const flownode_t *flownode)
{
const dagnode_t *dag;
dag_calc_node_costs (flownode->dag);
for (dag = flownode->dag; dag; dag = dag->next) {
//if (!dag->a || (strcmp (dag->label->opcode, ".=") && !dag->identifiers))
// continue;
dag_gencode (block, dag);
}
}