#include <stdlib.h>#include <stdio.h>#include <inttypes.h>#include <stdarg.h>#include <ctype.h>#include <string.h>#include <assert.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h> #include "util.h"#include "parse.h"#include "mi.h" static voidcheckundef(Node *n, Reaching *r, Bitset *reach, Bitset *kill){	size_t i, j, did;	Node *def;	Type *t; 	if (n->type != Nexpr)		return;	if (exprop(n) == Ovar) {		did = n->expr.did;		if (decls[did]->decl.isconst)			return;		for (j = 0; j < r->ndefs[did]; j++) {			t = tybase(exprtype(n));			if (t->type == Tystruct || t->type == Tyunion || t->type == Tyarray ||				t->type == Tytuple || t->type == Tyvoid)				continue;			if (bshas(kill, r->defs[did][j]))				continue;			if (!bshas(reach, r->defs[did][j]))				continue;			def = nodes[r->defs[did][j]];			if (exprop(def) == Oundef)				fatal(n, "%s used before definition", namestr(n->expr.args[0]));		}	} else {		switch (exprop(n)) {		case Oset:		case Oasn:		case Oblit:			checkundef(n->expr.args[1], r, reach, kill);			break;		case Oaddr:		case Oslice:			/* these don't actually look at the value of args[0], so they're ok. */			for (i = 1; i < n->expr.nargs; i++)				checkundef(n->expr.args[i], r, reach, kill);			break;		case Ocall:			for (i = 1; i < n->expr.nargs; i++)				if (exprop(n->expr.args[i]) != Oaddr)					checkundef(n->expr.args[i], r, reach, kill);			break;		default:			for (i = 0; i < n->expr.nargs; i++)				checkundef(n->expr.args[i], r, reach, kill);			break;		}	}} static voidcheckreach(Cfg *cfg){	Bitset *reach, *kill;	size_t i, j, k;	Reaching *r;	Node *n, *m;	Bb *bb; 	r = reaching(cfg);	for (i = 0; i < cfg->nbb; i++) {		bb = cfg->bb[i];		if (!bb)			continue;		reach = bsdup(r->in[i]);		kill = mkbs();		for (j = 0; j < bb->nnl; j++) {			n = bb->nl[j];			if (exprop(n) == Oundef) {				bsput(reach, n->nid);			} else {				m = assignee(n);				if (m)					for (k = 0; k < r->ndefs[m->expr.did]; k++)						bsput(kill, r->defs[m->expr.did][k]);				checkundef(n, r, reach, kill);			}		}		bsfree(reach);		bsfree(kill);	}	reachingfree(r);} static voidcheckpredret(Cfg *cfg, Bb *bb){	Bb *pred;	Op op;	size_t i; 	for (i = 0; bsiter(bb->pred, &i); i++) {		pred = cfg->bb[i];		if (pred->nnl == 0) {			checkpredret(cfg, pred);		} else {			op = exprop(pred->nl[pred->nnl - 1]);			if (op != Oret && op != Odead) {				fatal(pred->nl[pred->nnl-1], "Reaches end of function without return\n");			}		}	}} static voidcheckret(Cfg *cfg){	Type *ft; 	ft = tybase(decltype(cfg->fn));	assert(ft->type == Tyfunc || ft->type == Tycode);	if (ft->sub[0]->type == Tyvoid)		return; 	checkpredret(cfg, cfg->end);} voidcheck(Cfg *cfg){	checkret(cfg);	checkreach(cfg);}