557 lines
12 KiB
C
557 lines
12 KiB
C
/* $Id$ */
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/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* C O N T R O L F L O W
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*
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* M A I N R O U T I N E
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <em_mnem.h>
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#include <em_pseu.h>
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#include <em_spec.h>
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#include <em_flag.h>
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#include <em_mes.h>
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#include "../share/types.h"
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#include "../share/debug.h"
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#include "../share/map.h"
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#include "../share/files.h"
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#include "../share/global.h"
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#include "../share/alloc.h"
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#include "../share/lset.h"
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#include "../share/cset.h"
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#include "../share/get.h"
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#include "../share/put.h"
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#include "../share/def.h"
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#include "cf.h"
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#include "cf_succ.h"
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#include "cf_idom.h"
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#include "cf_loop.h"
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#define newcfbx() (bext_p) newstruct(bext_cf)
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#define oldcfbx(x) oldstruct(bext_cf,x)
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extern char em_flag[];
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STATIC cset lpi_set; /* set of procedures used in LPI instruction */
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STATIC cset cai_set; /* set of all procedures doing a CAI */
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/* The procedure getbblocks reads the EM textfile and
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* partitions every procedure into a number of basic blocks.
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*/
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#define LABEL0 0
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#define LABEL 1
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#define NORMAL 2
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#define JUMP 3
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#define END 4
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#define AFTERPRO 5
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#define INIT 6
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/* These global variables are used by getbblocks and nextblock. */
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STATIC bblock_p b, *bp; /* b is the current basic block, bp is
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* the address where the next block has
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* to be linked.
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*/
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STATIC line_p lnp, *lp; /* lnp is the current line, lp is
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* the address where the next line
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* has to be linked.
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*/
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STATIC short state; /* We use a finite state machine with the
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* following states:
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* LABEL0: after the first (successive)
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* instruction label.
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* LABEL1: after at least two successive
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* instruction labels.
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* NORMAL: after a normal instruction.
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* JUMP: after a branch (conditional,
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* unconditional or CSA/CSB).
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* END: after an END pseudo
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* AFTERPRO: after we've read a PRO pseudo
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* INIT: initial state
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*/
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STATIC nextblock()
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{
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/* allocate a new basic block structure and
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* set b, bp and lp.
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*/
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b = *bp = freshblock();
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bp = &b->b_next;
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b->b_start = lnp;
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b->b_succ = Lempty_set();
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b->b_pred = Lempty_set();
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b->b_extend = newcfbx(); /* basic block extension for CF */
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b->b_extend->bx_cf.bx_bucket = Lempty_set();
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b->b_extend->bx_cf.bx_semi = 0;
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lp = &lnp->l_next;
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#ifdef TRACE
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fprintf(stderr,"new basic block, id = %d\n",lastbid);
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#endif
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}
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STATIC short kind(lnp)
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line_p lnp;
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{
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/* determine if lnp is a label, branch, end or otherwise */
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short instr;
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byte flow;
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if ((instr = INSTR(lnp)) == op_lab) return (short) LABEL;
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if (instr == ps_end) return (short) END;
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if (instr > sp_lmnem) return (short) NORMAL; /* pseudo */
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if ((flow = (em_flag[instr-sp_fmnem] & EM_FLO)) == FLO_C ||
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flow == FLO_T) return (short) JUMP; /* conditional/uncond. jump */
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return (short) NORMAL;
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}
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STATIC line_p doread_line(p_out)
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proc_p *p_out;
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{
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/* read a line, and check pseudos for procedure addresses */
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register line_p lnp = read_line(p_out);
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if (lnp && TYPE(lnp) == OPLIST && INSTR(lnp) != ps_mes) {
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register arg_p arg = ARG(lnp);
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while (arg) {
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if (arg->a_type == ARGPROC) {
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Cadd(arg->a_a.a_proc->p_id, &lpi_set);
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arg->a_a.a_proc->p_flags1 |= PF_LPI;
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}
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arg = arg->a_next;
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}
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}
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return lnp;
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}
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STATIC bool getbblocks(fp,kind_out,n_out,g_out,l_out)
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FILE *fp;
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short *kind_out;
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short *n_out;
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bblock_p *g_out;
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line_p *l_out;
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{
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bblock_p head = (bblock_p) 0;
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line_p headl = (line_p) 0;
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curproc = (proc_p) 0;
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/* curproc will get a value when we encounter a PRO pseudo.
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* If there is no such pseudo, we're reading only data
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* declarations or messages (outside any proc.).
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*/
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curinp = fp;
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lastbid = (block_id) 0; /* block identier */
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state = INIT; /* initial state */
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bp = &head;
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for (;;) {
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#ifdef TRACE
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fprintf(stderr,"state = %d\n",state);
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#endif
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switch(state) {
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case LABEL0:
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nextblock();
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/* Fall through !! */
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case LABEL:
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lbmap[INSTRLAB(lnp)] = b;
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/* The lbmap table contains for each
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* label_id the basic block of that label.
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*/
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lnp = doread_line(&curproc);
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state = kind(lnp);
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if (state != END) {
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*lp = lnp;
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lp = &lnp->l_next;
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}
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break;
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case NORMAL:
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lnp = doread_line(&curproc);
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if ( (state = kind(lnp)) == LABEL) {
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/* If we come accross a label
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* here, it must be the beginning
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* of a new basic block.
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*/
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state = LABEL0;
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} else {
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if (state != END) {
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*lp = lnp;
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lp = &lnp->l_next;
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}
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}
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break;
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case JUMP:
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lnp = doread_line(&curproc);
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/* fall through ... */
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case AFTERPRO:
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switch(state = kind(lnp)) {
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case LABEL:
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state = LABEL0;
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break;
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case JUMP:
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case NORMAL:
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nextblock();
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break;
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}
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break;
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case END:
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*lp = lnp;
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#ifdef TRACE
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fprintf(stderr,"at end of proc, %d blocks\n",lastbid);
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#endif
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if (head == (bblock_p) 0) {
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*kind_out = LDATA;
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*l_out = headl;
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} else {
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*kind_out = LTEXT;
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*g_out = head;
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*n_out = (short) lastbid;
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/* number of basic blocks */
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}
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return TRUE;
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case INIT:
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lnp = doread_line(&curproc);
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if (feof(curinp)) return FALSE;
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if (INSTR(lnp) == ps_pro) {
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state = AFTERPRO;
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} else {
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state = NORMAL;
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headl = lnp;
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lp = &lnp->l_next;
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}
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break;
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}
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}
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}
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STATIC interproc_analysis(p)
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proc_p p;
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{
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/* Interprocedural analysis of a procedure p determines:
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* - all procedures called by p (the 'call graph')
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* - the set of objects changed by p (directly)
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* - whether p does a load-indirect (loi,lof etc.)
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* - whether p does a store-indirect (sti, stf etc.)
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* The changed/used variables information will be
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* transitively closed, i.e. if P calls Q and Q changes
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* a variable X, the P changes X too.
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* (The same applies for used variables and for use/store
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* indirect).
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* The transitive closure will be computed by main
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* after all procedures have been processed.
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*/
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bblock_p b;
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line_p lnp;
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bool inloop;
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/* Allocate memory for structs and sets */
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p->p_use = newuse();
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p->p_change = newchange();
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p->p_change->c_ext = Cempty_set(olength);
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p->p_calling = Cempty_set(plength);
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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inloop = (Lnrelems(b->b_loops) > 0);
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for (lnp = b->b_start; lnp != (line_p) 0; lnp = lnp->l_next) {
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/* for all instructions of p do */
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switch(INSTR(lnp)) {
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case op_cal:
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Cadd(PROC(lnp)->p_id, &p->p_calling);
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/* add called proc to p_calling */
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if (inloop) {
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CALLED_IN_LOOP(PROC(lnp));
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}
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break;
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case op_cai:
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Cadd(p->p_id,&cai_set);
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break;
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case op_lpi:
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Cadd(PROC(lnp)->p_id, &lpi_set);
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/* All procedures that have their names used
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* in an lpi instruction, may be called via
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* a cai instruction.
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*/
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PROC(lnp)->p_flags1 |= PF_LPI;
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break;
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case op_ste:
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case op_sde:
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case op_ine:
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case op_dee:
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case op_zre:
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Cadd(OBJ(lnp)->o_id, &p->p_change->c_ext);
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/* Add changed object to c_ext */
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break;
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case op_lil:
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case op_lof:
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case op_loi:
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case op_los:
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case op_lar:
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p->p_use->u_flags |= UF_INDIR;
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/* p does a load-indirect */
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break;
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case op_sil:
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case op_stf:
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case op_sti:
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case op_sts:
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case op_sar:
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p->p_change->c_flags |= CF_INDIR;
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/* p does a store-indirect */
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break;
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case op_blm:
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case op_bls:
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p->p_use->u_flags |= UF_INDIR;
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p->p_change->c_flags |= CF_INDIR;
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/* p does both */
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break;
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case op_mon:
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printf("mon not yet implemented\n");
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break;
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case op_lxl:
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case op_lxa:
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curproc->p_flags1 |= PF_ENVIRON;
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break;
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case op_lor:
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case op_str:
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if (SHORT(lnp) == 0) {
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curproc->p_flags1 |= PF_ENVIRON;
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}
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break;
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case ps_mes:
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if (aoff(ARG(lnp),0) == ms_gto) {
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ENTERED_WITH_GTO(curproc);
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}
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break;
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}
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}
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}
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}
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STATIC cf_cleanproc(p)
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proc_p p;
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{
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/* Remove the extended data structures of p */
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register bblock_p b;
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register Lindex pi;
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loop_p lp;
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for (b = p->p_start; b != (bblock_p) 0; b = b->b_next) {
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oldcfbx(b->b_extend);
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}
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for (pi = Lfirst(p->p_loops); pi != (Lindex) 0; pi = Lnext(pi,
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p->p_loops)) {
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lp = (loop_p) Lelem(pi);
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oldcflpx(lp->lp_extend);
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}
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}
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#define CH_CHANGE_INDIR(ch) ((ch->c_flags & CF_INDIR) != 0)
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#define USE_INDIR(us) ((us->u_flags & UF_INDIR) != 0)
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#define CALLS_UNKNOWN(p) (p->p_flags1 & (byte) PF_CALUNKNOWN)
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#define ENVIRON(p) (p->p_flags1 & (byte) PF_ENVIRON)
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STATIC bool add_info(q,p)
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proc_p q,p;
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{
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/* Determine the consequences for used/changed variables info
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* of the fact that p calls q. If e.g. q changes a variable X
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* then p changes this variable too. This routine is an
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* auxiliary routine of the transitive closure process.
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* The returned value indicates if there was any change in
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* the information of p.
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*/
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change_p chp, chq;
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use_p usp, usq;
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bool diff = FALSE;
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chp = p->p_change;
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chq = q->p_change;
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usp = p->p_use;
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usq = q->p_use;
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if (!BODY_KNOWN(q)) {
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/* q is a procedure of which the body is not available
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* as EM text.
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*/
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if (CALLS_UNKNOWN(p)) {
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return FALSE;
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/* p already called an unknown procedure */
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} else {
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p->p_flags1 |= PF_CALUNKNOWN;
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return TRUE;
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}
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}
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if (CALLS_UNKNOWN(q)) {
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/* q calls a procedure of which the body is not available
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* as EM text.
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*/
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if (!CALLS_UNKNOWN(p)) {
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p->p_flags1 |= PF_CALUNKNOWN;
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diff = TRUE;
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}
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}
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if (IS_CALLED_IN_LOOP(p) && !IS_CALLED_IN_LOOP(q)) {
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CALLED_IN_LOOP(q);
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diff = TRUE;
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}
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if (!Cis_subset(chq->c_ext, chp->c_ext)) {
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/* q changes global variables (objects) that
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* p did not (yet) change. Add all variables
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* changed by q to the c_ext set of p.
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*/
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Cjoin(chq->c_ext, &chp->c_ext);
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diff = TRUE;
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}
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if (CH_CHANGE_INDIR(chq) && !CH_CHANGE_INDIR(chp)) {
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/* q does a change-indirect (sil etc.)
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* and p did not (yet).
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*/
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chp->c_flags |= CF_INDIR;
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diff = TRUE;
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}
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if (USE_INDIR(usq) && !USE_INDIR(usp)) {
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/* q does a use-indirect (lil etc.)
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* and p dis not (yet).
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*/
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usp->u_flags |= UF_INDIR;
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diff = TRUE;
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}
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if (ENVIRON(q) && !ENVIRON(p)) {
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/* q uses or changes local variables in its
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* environment while p does not (yet).
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*/
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p->p_flags1 |= PF_ENVIRON;
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diff = TRUE;
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}
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return diff;
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}
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STATIC trans_clos(head)
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proc_p head;
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{
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/* Compute the transitive closure of the used/changed
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* variable information.
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*/
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register proc_p p,q;
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Cindex i;
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bool changes = TRUE;
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while(changes) {
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changes = FALSE;
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for (p = head; p != (proc_p) 0; p = p->p_next) {
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if (!BODY_KNOWN(p)) continue;
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for (i = Cfirst(p->p_calling); i != (Cindex) 0;
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i = Cnext(i,p->p_calling)) {
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q = pmap[Celem(i)];
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if (add_info(q,p)) {
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changes = TRUE;
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}
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}
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}
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}
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}
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indir_calls()
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{
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Cindex i;
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proc_p p;
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for (i = Cfirst(cai_set); i != (Cindex) 0; i = Cnext(i,cai_set)) {
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p = pmap[Celem(i)]; /* p does a CAI */
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Cjoin(lpi_set, &p->p_calling);
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}
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Cdeleteset(lpi_set);
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Cdeleteset(cai_set);
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}
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main(argc,argv)
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int argc;
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char *argv[];
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{
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FILE *f, *f2, *gf2; /* The EM input, EM output, basic block output */
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bblock_p g;
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short n, kind;
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line_p l;
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linecount = 0;
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fproc = getptable(pname); /* proc table */
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fdblock = getdtable(dname); /* data block table */
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lpi_set = Cempty_set(plength);
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cai_set = Cempty_set(plength);
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if ((f = fopen(lname,"r")) == NULL) {
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error("cannot open %s", lname);
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}
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if ((f2 = fopen(lname2,"w")) == NULL) {
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error("cannot open %s", lname2);
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}
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if ((gf2 = fopen(bname2,"w")) == NULL) {
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error("cannot open %s",bname2);
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}
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while (getbblocks(f,&kind,&n,&g,&l)) {
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/* read EM text of one unit and
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* (if it is a procedure)
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* partition it into n basic blocks.
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*/
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if (kind == LDATA) {
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putunit(LDATA,(proc_p) 0,l,gf2,f2);
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} else {
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curproc->p_start = g;
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/* The global variable curproc points to the
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* current procedure. It is set by getbblocks
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*/
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control_flow(g); /* compute pred and succ */
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dominators(g,n); /* compute immediate dominators */
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loop_detection(curproc); /* compute loops */
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interproc_analysis(curproc);
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/* Interprocedural analysis */
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cf_cleanproc(curproc);
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putunit(LTEXT,curproc,(line_p) 0,gf2,f2);
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|
/* output control flow graph + text */
|
|
}
|
|
}
|
|
fclose(f);
|
|
fclose(f2);
|
|
fclose(gf2);
|
|
indir_calls();
|
|
trans_clos(fproc);
|
|
/* Compute transitive closure of used/changed
|
|
* variables information for every procedure.
|
|
*/
|
|
if ((f = fopen(dname2,"w")) == NULL) {
|
|
error("cannot open %s",dname2);
|
|
}
|
|
putdtable(fdblock,f);
|
|
if ((f = fopen(pname2,"w")) == NULL) {
|
|
error("cannot open %s",pname2);
|
|
}
|
|
putptable(fproc,f,TRUE);
|
|
exit(0);
|
|
}
|