quakeforge/tools/qfcc/source/dags.c
Bill Currie 1100efba54 Nuke find_operands in favor of flow_analyze_statement.
flow_analyze_statement uses the statement type to quickly determin which
operands are inputs and which are outputs. It takes (optional) sets for
used variables, defined variables and killed variables (only partially
working, but I don't actually use kill sets yet). It also takes an optional
array for storing the operands: index 0 is the output, 1-3 are the inputs.
flow_analyze_statement clears any given sets on entry.

Live variable analysis now uses the sets rather than individual vars. Much
cleaner code :).

Dags are completely broken.
2012-11-16 19:33:37 +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 (st_none, opcode, expr);//FIXME
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 = 0;
//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);
}
}