| 1 |
4 |
hellwig |
#include "c.h"
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static char rcsid[] = "$Id: stmt.c,v 1.1 2002/08/28 23:12:46 drh Exp $";
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#define SWSIZE 512
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#define den(i,j) ((j-buckets[i]+1.0)/(v[j]-v[buckets[i]]+1))
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struct code codehead = { Start };
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Code codelist = &codehead;
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float density = 0.5;
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Table stmtlabs;
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static int foldcond(Tree e1, Tree e2);
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static void caselabel(Swtch, long, int);
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static void cmp(int, Symbol, long, int);
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static Tree conditional(int);
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static void dostmt(int, Swtch, int);
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static int equal(Symbol, Symbol);
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static void forstmt(int, Swtch, int);
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static void ifstmt(int, int, Swtch, int);
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static Symbol localaddr(Tree);
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static void stmtlabel(void);
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static void swstmt(int, int, int);
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static void whilestmt(int, Swtch, int);
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Code code(int kind) {
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Code cp;
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if (!reachable(kind))
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warning("unreachable code\n");
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NEW(cp, FUNC);
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cp->kind = kind;
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cp->prev = codelist;
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cp->next = NULL;
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codelist->next = cp;
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codelist = cp;
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return cp;
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}
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int reachable(int kind) {
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Code cp;
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if (kind > Start) {
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Code cp;
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for (cp = codelist; cp->kind < Label; )
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cp = cp->prev;
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if (cp->kind == Jump || cp->kind == Switch)
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return 0;
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}
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return 1;
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}
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void addlocal(Symbol p) {
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if (!p->defined) {
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code(Local)->u.var = p;
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p->defined = 1;
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p->scope = level;
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}
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}
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void definept(Coordinate *p) {
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Code cp = code(Defpoint);
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cp->u.point.src = p ? *p : src;
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cp->u.point.point = npoints;
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if (ncalled > 0) {
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int n = findcount(cp->u.point.src.file,
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cp->u.point.src.x, cp->u.point.src.y);
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if (n > 0)
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refinc = (float)n/ncalled;
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}
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if (glevel > 2) locus(identifiers, &cp->u.point.src);
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if (events.points && reachable(Gen))
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{
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Tree e = NULL;
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apply(events.points, &cp->u.point.src, &e);
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if (e)
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listnodes(e, 0, 0);
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}
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}
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void statement(int loop, Swtch swp, int lev) {
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float ref = refinc;
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if (Aflag >= 2 && lev == 15)
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warning("more than 15 levels of nested statements\n");
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switch (t) {
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case IF: ifstmt(genlabel(2), loop, swp, lev + 1);
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break;
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case WHILE: whilestmt(genlabel(3), swp, lev + 1); break;
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case DO: dostmt(genlabel(3), swp, lev + 1); expect(';');
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break;
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case FOR: forstmt(genlabel(4), swp, lev + 1);
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break;
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case BREAK: walk(NULL, 0, 0);
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definept(NULL);
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if (swp && swp->lab > loop)
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branch(swp->lab + 1);
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else if (loop)
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branch(loop + 2);
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else
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error("illegal break statement\n");
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t = gettok(); expect(';');
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break;
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| 103 |
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case CONTINUE: walk(NULL, 0, 0);
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definept(NULL);
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if (loop)
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branch(loop + 1);
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else
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error("illegal continue statement\n");
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| 110 |
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t = gettok(); expect(';');
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break;
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case SWITCH: swstmt(loop, genlabel(2), lev + 1);
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break;
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case CASE: {
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int lab = genlabel(1);
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if (swp == NULL)
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error("illegal case label\n");
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definelab(lab);
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while (t == CASE) {
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| 121 |
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static char stop[] = { IF, ID, 0 };
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Tree p;
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t = gettok();
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p = constexpr(0);
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if (generic(p->op) == CNST && isint(p->type)) {
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| 126 |
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if (swp) {
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needconst++;
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p = cast(p, swp->sym->type);
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if (p->type->op == UNSIGNED)
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p->u.v.i = extend(p->u.v.u, p->type);
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needconst--;
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caselabel(swp, p->u.v.i, lab);
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}
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} else
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| 135 |
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error("case label must be a constant integer expression\n");
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| 136 |
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| 137 |
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test(':', stop);
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| 138 |
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}
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| 139 |
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statement(loop, swp, lev);
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| 140 |
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} break;
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| 141 |
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case DEFAULT: if (swp == NULL)
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| 142 |
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error("illegal default label\n");
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| 143 |
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else if (swp->deflab)
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| 144 |
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error("extra default label\n");
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| 145 |
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else {
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| 146 |
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swp->deflab = findlabel(swp->lab);
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| 147 |
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definelab(swp->deflab->u.l.label);
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| 148 |
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}
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| 149 |
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t = gettok();
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| 150 |
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expect(':');
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| 151 |
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statement(loop, swp, lev); break;
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| 152 |
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case RETURN: {
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| 153 |
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Type rty = freturn(cfunc->type);
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| 154 |
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t = gettok();
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| 155 |
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definept(NULL);
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| 156 |
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if (t != ';')
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| 157 |
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if (rty == voidtype) {
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| 158 |
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error("extraneous return value\n");
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| 159 |
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expr(0);
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| 160 |
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retcode(NULL);
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| 161 |
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} else
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retcode(expr(0));
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| 163 |
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else {
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| 164 |
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if (rty != voidtype) {
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warning("missing return value\n");
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retcode(cnsttree(inttype, 0L));
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| 167 |
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} else
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| 168 |
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retcode(NULL);
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| 169 |
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}
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| 170 |
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branch(cfunc->u.f.label);
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| 171 |
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} expect(';');
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| 172 |
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break;
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| 173 |
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| 174 |
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case '{': compound(loop, swp, lev + 1); break;
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| 175 |
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case ';': definept(NULL); t = gettok(); break;
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| 176 |
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case GOTO: walk(NULL, 0, 0);
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| 177 |
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definept(NULL);
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| 178 |
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t = gettok();
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| 179 |
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if (t == ID) {
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| 180 |
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Symbol p = lookup(token, stmtlabs);
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| 181 |
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if (p == NULL) {
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| 182 |
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p = install(token, &stmtlabs, 0, FUNC);
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| 183 |
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p->scope = LABELS;
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| 184 |
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p->u.l.label = genlabel(1);
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| 185 |
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p->src = src;
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| 186 |
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}
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| 187 |
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use(p, src);
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| 188 |
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branch(p->u.l.label);
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| 189 |
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t = gettok();
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| 190 |
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} else
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| 191 |
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error("missing label in goto\n"); expect(';');
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| 192 |
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break;
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| 193 |
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| 194 |
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case ID: if (getchr() == ':') {
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stmtlabel();
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statement(loop, swp, lev);
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break;
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| 198 |
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}
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| 199 |
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default: definept(NULL);
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| 200 |
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if (kind[t] != ID) {
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| 201 |
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error("unrecognized statement\n");
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| 202 |
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t = gettok();
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| 203 |
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} else {
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| 204 |
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Tree e = expr0(0);
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| 205 |
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listnodes(e, 0, 0);
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| 206 |
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if (nodecount == 0 || nodecount > 200)
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| 207 |
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walk(NULL, 0, 0);
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| 208 |
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else if (glevel) walk(NULL, 0, 0);
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| 209 |
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deallocate(STMT);
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| 210 |
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} expect(';');
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| 211 |
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break;
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| 212 |
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| 213 |
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}
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| 214 |
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if (kind[t] != IF && kind[t] != ID
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| 215 |
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&& t != '}' && t != EOI) {
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| 216 |
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static char stop[] = { IF, ID, '}', 0 };
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| 217 |
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error("illegal statement termination\n");
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| 218 |
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skipto(0, stop);
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| 219 |
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}
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| 220 |
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refinc = ref;
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| 221 |
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}
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| 222 |
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| 223 |
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static void ifstmt(int lab, int loop, Swtch swp, int lev) {
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| 224 |
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t = gettok();
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| 225 |
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expect('(');
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| 226 |
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definept(NULL);
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| 227 |
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walk(conditional(')'), 0, lab);
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| 228 |
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refinc /= 2.0;
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| 229 |
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statement(loop, swp, lev);
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| 230 |
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if (t == ELSE) {
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| 231 |
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branch(lab + 1);
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| 232 |
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t = gettok();
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| 233 |
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definelab(lab);
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| 234 |
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statement(loop, swp, lev);
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| 235 |
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if (findlabel(lab + 1)->ref)
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| 236 |
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definelab(lab + 1);
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| 237 |
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} else
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| 238 |
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definelab(lab);
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| 239 |
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}
|
| 240 |
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static Tree conditional(int tok) {
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| 241 |
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Tree p = expr(tok);
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| 242 |
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| 243 |
|
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if (Aflag > 1 && isfunc(p->type))
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| 244 |
|
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warning("%s used in a conditional expression\n",
|
| 245 |
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funcname(p));
|
| 246 |
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return cond(p);
|
| 247 |
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}
|
| 248 |
|
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static void stmtlabel(void) {
|
| 249 |
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Symbol p = lookup(token, stmtlabs);
|
| 250 |
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|
| 251 |
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if (p == NULL) {
|
| 252 |
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p = install(token, &stmtlabs, 0, FUNC);
|
| 253 |
|
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p->scope = LABELS;
|
| 254 |
|
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p->u.l.label = genlabel(1);
|
| 255 |
|
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p->src = src;
|
| 256 |
|
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}
|
| 257 |
|
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if (p->defined)
|
| 258 |
|
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error("redefinition of label `%s' previously defined at %w\n", p->name, &p->src);
|
| 259 |
|
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| 260 |
|
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p->defined = 1;
|
| 261 |
|
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definelab(p->u.l.label);
|
| 262 |
|
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t = gettok();
|
| 263 |
|
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expect(':');
|
| 264 |
|
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}
|
| 265 |
|
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static void forstmt(int lab, Swtch swp, int lev) {
|
| 266 |
|
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int once = 0;
|
| 267 |
|
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Tree e1 = NULL, e2 = NULL, e3 = NULL;
|
| 268 |
|
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Coordinate pt2, pt3;
|
| 269 |
|
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|
| 270 |
|
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t = gettok();
|
| 271 |
|
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expect('(');
|
| 272 |
|
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definept(NULL);
|
| 273 |
|
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if (kind[t] == ID)
|
| 274 |
|
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e1 = texpr(expr0, ';', FUNC);
|
| 275 |
|
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else
|
| 276 |
|
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expect(';');
|
| 277 |
|
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walk(e1, 0, 0);
|
| 278 |
|
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pt2 = src;
|
| 279 |
|
|
refinc *= 10.0;
|
| 280 |
|
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if (kind[t] == ID)
|
| 281 |
|
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e2 = texpr(conditional, ';', FUNC);
|
| 282 |
|
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else
|
| 283 |
|
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expect(';');
|
| 284 |
|
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pt3 = src;
|
| 285 |
|
|
if (kind[t] == ID)
|
| 286 |
|
|
e3 = texpr(expr0, ')', FUNC);
|
| 287 |
|
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else {
|
| 288 |
|
|
static char stop[] = { IF, ID, '}', 0 };
|
| 289 |
|
|
test(')', stop);
|
| 290 |
|
|
}
|
| 291 |
|
|
if (e2) {
|
| 292 |
|
|
once = foldcond(e1, e2);
|
| 293 |
|
|
if (!once)
|
| 294 |
|
|
branch(lab + 3);
|
| 295 |
|
|
}
|
| 296 |
|
|
definelab(lab);
|
| 297 |
|
|
statement(lab, swp, lev);
|
| 298 |
|
|
definelab(lab + 1);
|
| 299 |
|
|
definept(&pt3);
|
| 300 |
|
|
if (e3)
|
| 301 |
|
|
walk(e3, 0, 0);
|
| 302 |
|
|
if (e2) {
|
| 303 |
|
|
if (!once)
|
| 304 |
|
|
definelab(lab + 3);
|
| 305 |
|
|
definept(&pt2);
|
| 306 |
|
|
walk(e2, lab, 0);
|
| 307 |
|
|
} else {
|
| 308 |
|
|
definept(&pt2);
|
| 309 |
|
|
branch(lab);
|
| 310 |
|
|
}
|
| 311 |
|
|
if (findlabel(lab + 2)->ref)
|
| 312 |
|
|
definelab(lab + 2);
|
| 313 |
|
|
}
|
| 314 |
|
|
static void swstmt(int loop, int lab, int lev) {
|
| 315 |
|
|
Tree e;
|
| 316 |
|
|
struct swtch sw;
|
| 317 |
|
|
Code head, tail;
|
| 318 |
|
|
|
| 319 |
|
|
t = gettok();
|
| 320 |
|
|
expect('(');
|
| 321 |
|
|
definept(NULL);
|
| 322 |
|
|
e = expr(')');
|
| 323 |
|
|
if (!isint(e->type)) {
|
| 324 |
|
|
error("illegal type `%t' in switch expression\n",
|
| 325 |
|
|
e->type);
|
| 326 |
|
|
e = retype(e, inttype);
|
| 327 |
|
|
}
|
| 328 |
|
|
e = cast(e, promote(e->type));
|
| 329 |
|
|
if (generic(e->op) == INDIR && isaddrop(e->kids[0]->op)
|
| 330 |
|
|
&& e->kids[0]->u.sym->type == e->type
|
| 331 |
|
|
&& !isvolatile(e->kids[0]->u.sym->type)) {
|
| 332 |
|
|
sw.sym = e->kids[0]->u.sym;
|
| 333 |
|
|
walk(NULL, 0, 0);
|
| 334 |
|
|
} else {
|
| 335 |
|
|
sw.sym = genident(REGISTER, e->type, level);
|
| 336 |
|
|
addlocal(sw.sym);
|
| 337 |
|
|
walk(asgn(sw.sym, e), 0, 0);
|
| 338 |
|
|
}
|
| 339 |
|
|
head = code(Switch);
|
| 340 |
|
|
sw.lab = lab;
|
| 341 |
|
|
sw.deflab = NULL;
|
| 342 |
|
|
sw.ncases = 0;
|
| 343 |
|
|
sw.size = SWSIZE;
|
| 344 |
|
|
sw.values = newarray(SWSIZE, sizeof *sw.values, FUNC);
|
| 345 |
|
|
sw.labels = newarray(SWSIZE, sizeof *sw.labels, FUNC);
|
| 346 |
|
|
refinc /= 10.0;
|
| 347 |
|
|
statement(loop, &sw, lev);
|
| 348 |
|
|
if (sw.deflab == NULL) {
|
| 349 |
|
|
sw.deflab = findlabel(lab);
|
| 350 |
|
|
definelab(lab);
|
| 351 |
|
|
if (sw.ncases == 0)
|
| 352 |
|
|
warning("switch statement with no cases\n");
|
| 353 |
|
|
}
|
| 354 |
|
|
if (findlabel(lab + 1)->ref)
|
| 355 |
|
|
definelab(lab + 1);
|
| 356 |
|
|
tail = codelist;
|
| 357 |
|
|
codelist = head->prev;
|
| 358 |
|
|
codelist->next = head->prev = NULL;
|
| 359 |
|
|
if (sw.ncases > 0)
|
| 360 |
|
|
swgen(&sw);
|
| 361 |
|
|
branch(lab);
|
| 362 |
|
|
head->next->prev = codelist;
|
| 363 |
|
|
codelist->next = head->next;
|
| 364 |
|
|
codelist = tail;
|
| 365 |
|
|
}
|
| 366 |
|
|
static void caselabel(Swtch swp, long val, int lab) {
|
| 367 |
|
|
int k;
|
| 368 |
|
|
|
| 369 |
|
|
if (swp->ncases >= swp->size)
|
| 370 |
|
|
{
|
| 371 |
|
|
long *vals = swp->values;
|
| 372 |
|
|
Symbol *labs = swp->labels;
|
| 373 |
|
|
swp->size *= 2;
|
| 374 |
|
|
swp->values = newarray(swp->size, sizeof *swp->values, FUNC);
|
| 375 |
|
|
swp->labels = newarray(swp->size, sizeof *swp->labels, FUNC);
|
| 376 |
|
|
for (k = 0; k < swp->ncases; k++) {
|
| 377 |
|
|
swp->values[k] = vals[k];
|
| 378 |
|
|
swp->labels[k] = labs[k];
|
| 379 |
|
|
}
|
| 380 |
|
|
}
|
| 381 |
|
|
k = swp->ncases;
|
| 382 |
|
|
for ( ; k > 0 && swp->values[k-1] >= val; k--) {
|
| 383 |
|
|
swp->values[k] = swp->values[k-1];
|
| 384 |
|
|
swp->labels[k] = swp->labels[k-1];
|
| 385 |
|
|
}
|
| 386 |
|
|
if (k < swp->ncases && swp->values[k] == val)
|
| 387 |
|
|
error("duplicate case label `%d'\n", val);
|
| 388 |
|
|
swp->values[k] = val;
|
| 389 |
|
|
swp->labels[k] = findlabel(lab);
|
| 390 |
|
|
++swp->ncases;
|
| 391 |
|
|
if (Aflag >= 2 && swp->ncases == 258)
|
| 392 |
|
|
warning("more than 257 cases in a switch\n");
|
| 393 |
|
|
}
|
| 394 |
|
|
void swgen(Swtch swp) {
|
| 395 |
|
|
int *buckets, k, n;
|
| 396 |
|
|
long *v = swp->values;
|
| 397 |
|
|
|
| 398 |
|
|
buckets = newarray(swp->ncases + 1,
|
| 399 |
|
|
sizeof *buckets, FUNC);
|
| 400 |
|
|
for (n = k = 0; k < swp->ncases; k++, n++) {
|
| 401 |
|
|
buckets[n] = k;
|
| 402 |
|
|
while (n > 0 && den(n-1, k) >= density)
|
| 403 |
|
|
n--;
|
| 404 |
|
|
}
|
| 405 |
|
|
buckets[n] = swp->ncases;
|
| 406 |
|
|
swcode(swp, buckets, 0, n - 1);
|
| 407 |
|
|
}
|
| 408 |
|
|
void swcode(Swtch swp, int b[], int lb, int ub) {
|
| 409 |
|
|
int hilab, lolab, l, u, k = (lb + ub)/2;
|
| 410 |
|
|
long *v = swp->values;
|
| 411 |
|
|
|
| 412 |
|
|
if (k > lb && k < ub) {
|
| 413 |
|
|
lolab = genlabel(1);
|
| 414 |
|
|
hilab = genlabel(1);
|
| 415 |
|
|
} else if (k > lb) {
|
| 416 |
|
|
lolab = genlabel(1);
|
| 417 |
|
|
hilab = swp->deflab->u.l.label;
|
| 418 |
|
|
} else if (k < ub) {
|
| 419 |
|
|
lolab = swp->deflab->u.l.label;
|
| 420 |
|
|
hilab = genlabel(1);
|
| 421 |
|
|
} else
|
| 422 |
|
|
lolab = hilab = swp->deflab->u.l.label;
|
| 423 |
|
|
l = b[k];
|
| 424 |
|
|
u = b[k+1] - 1;
|
| 425 |
|
|
if (u - l + 1 <= 3)
|
| 426 |
|
|
{
|
| 427 |
|
|
int i;
|
| 428 |
|
|
for (i = l; i <= u; i++)
|
| 429 |
|
|
cmp(EQ, swp->sym, v[i], swp->labels[i]->u.l.label);
|
| 430 |
|
|
if (k > lb && k < ub)
|
| 431 |
|
|
cmp(GT, swp->sym, v[u], hilab);
|
| 432 |
|
|
else if (k > lb)
|
| 433 |
|
|
cmp(GT, swp->sym, v[u], hilab);
|
| 434 |
|
|
else if (k < ub)
|
| 435 |
|
|
cmp(LT, swp->sym, v[l], lolab);
|
| 436 |
|
|
else
|
| 437 |
|
|
assert(lolab == hilab),
|
| 438 |
|
|
branch(lolab);
|
| 439 |
|
|
walk(NULL, 0, 0);
|
| 440 |
|
|
}
|
| 441 |
|
|
else {
|
| 442 |
|
|
Tree e;
|
| 443 |
|
|
Type ty = signedint(swp->sym->type);
|
| 444 |
|
|
Symbol table = genident(STATIC,
|
| 445 |
|
|
array(voidptype, u - l + 1, 0), GLOBAL);
|
| 446 |
|
|
(*IR->defsymbol)(table);
|
| 447 |
|
|
if (!isunsigned(swp->sym->type) || v[l] != 0)
|
| 448 |
|
|
cmp(LT, swp->sym, v[l], lolab);
|
| 449 |
|
|
cmp(GT, swp->sym, v[u], hilab);
|
| 450 |
|
|
e = (*optree['-'])(SUB, cast(idtree(swp->sym), ty), cnsttree(ty, v[l]));
|
| 451 |
|
|
if (e->type->size < unsignedptr->size)
|
| 452 |
|
|
e = cast(e, unsignedlong);
|
| 453 |
|
|
walk(tree(JUMP, voidtype,
|
| 454 |
|
|
rvalue((*optree['+'])(ADD, pointer(idtree(table)), e)), NULL),
|
| 455 |
|
|
0, 0);
|
| 456 |
|
|
code(Switch);
|
| 457 |
|
|
codelist->u.swtch.table = table;
|
| 458 |
|
|
codelist->u.swtch.sym = swp->sym;
|
| 459 |
|
|
codelist->u.swtch.deflab = swp->deflab;
|
| 460 |
|
|
codelist->u.swtch.size = u - l + 1;
|
| 461 |
|
|
codelist->u.swtch.values = &v[l];
|
| 462 |
|
|
codelist->u.swtch.labels = &swp->labels[l];
|
| 463 |
|
|
if (v[u] - v[l] + 1 >= 10000)
|
| 464 |
|
|
warning("switch generates a huge table\n");
|
| 465 |
|
|
}
|
| 466 |
|
|
if (k > lb) {
|
| 467 |
|
|
assert(lolab != swp->deflab->u.l.label);
|
| 468 |
|
|
definelab(lolab);
|
| 469 |
|
|
swcode(swp, b, lb, k - 1);
|
| 470 |
|
|
}
|
| 471 |
|
|
if (k < ub) {
|
| 472 |
|
|
assert(hilab != swp->deflab->u.l.label);
|
| 473 |
|
|
definelab(hilab);
|
| 474 |
|
|
swcode(swp, b, k + 1, ub);
|
| 475 |
|
|
}
|
| 476 |
|
|
}
|
| 477 |
|
|
static void cmp(int op, Symbol p, long n, int lab) {
|
| 478 |
|
|
Type ty = signedint(p->type);
|
| 479 |
|
|
|
| 480 |
|
|
listnodes(eqtree(op,
|
| 481 |
|
|
cast(idtree(p), ty),
|
| 482 |
|
|
cnsttree(ty, n)),
|
| 483 |
|
|
lab, 0);
|
| 484 |
|
|
}
|
| 485 |
|
|
void retcode(Tree p) {
|
| 486 |
|
|
Type ty;
|
| 487 |
|
|
|
| 488 |
|
|
if (p == NULL) {
|
| 489 |
|
|
if (events.returns)
|
| 490 |
|
|
apply(events.returns, cfunc, NULL);
|
| 491 |
|
|
return;
|
| 492 |
|
|
}
|
| 493 |
|
|
p = pointer(p);
|
| 494 |
|
|
ty = assign(freturn(cfunc->type), p);
|
| 495 |
|
|
if (ty == NULL) {
|
| 496 |
|
|
error("illegal return type; found `%t' expected `%t'\n",
|
| 497 |
|
|
p->type, freturn(cfunc->type));
|
| 498 |
|
|
return;
|
| 499 |
|
|
}
|
| 500 |
|
|
p = cast(p, ty);
|
| 501 |
|
|
if (retv)
|
| 502 |
|
|
{
|
| 503 |
|
|
if (iscallb(p))
|
| 504 |
|
|
p = tree(RIGHT, p->type,
|
| 505 |
|
|
tree(CALL+B, p->type,
|
| 506 |
|
|
p->kids[0]->kids[0], idtree(retv)),
|
| 507 |
|
|
rvalue(idtree(retv)));
|
| 508 |
|
|
else {
|
| 509 |
|
|
Type ty = retv->type->type;
|
| 510 |
|
|
assert(isstruct(ty));
|
| 511 |
|
|
if (ty->u.sym->u.s.cfields) {
|
| 512 |
|
|
ty->u.sym->u.s.cfields = 0;
|
| 513 |
|
|
p = asgntree(ASGN, rvalue(idtree(retv)), p);
|
| 514 |
|
|
ty->u.sym->u.s.cfields = 1;
|
| 515 |
|
|
} else
|
| 516 |
|
|
p = asgntree(ASGN, rvalue(idtree(retv)), p);
|
| 517 |
|
|
}
|
| 518 |
|
|
walk(p, 0, 0);
|
| 519 |
|
|
if (events.returns)
|
| 520 |
|
|
apply(events.returns, cfunc, rvalue(idtree(retv)));
|
| 521 |
|
|
return;
|
| 522 |
|
|
}
|
| 523 |
|
|
if (events.returns)
|
| 524 |
|
|
{
|
| 525 |
|
|
Symbol t1 = genident(AUTO, p->type, level);
|
| 526 |
|
|
addlocal(t1);
|
| 527 |
|
|
walk(asgn(t1, p), 0, 0);
|
| 528 |
|
|
apply(events.returns, cfunc, idtree(t1));
|
| 529 |
|
|
p = idtree(t1);
|
| 530 |
|
|
}
|
| 531 |
|
|
if (!isfloat(p->type))
|
| 532 |
|
|
p = cast(p, promote(p->type));
|
| 533 |
|
|
if (isptr(p->type))
|
| 534 |
|
|
{
|
| 535 |
|
|
Symbol q = localaddr(p);
|
| 536 |
|
|
if (q && (q->computed || q->generated))
|
| 537 |
|
|
warning("pointer to a %s is an illegal return value\n",
|
| 538 |
|
|
q->scope == PARAM ? "parameter" : "local");
|
| 539 |
|
|
else if (q)
|
| 540 |
|
|
warning("pointer to %s `%s' is an illegal return value\n",
|
| 541 |
|
|
q->scope == PARAM ? "parameter" : "local", q->name);
|
| 542 |
|
|
}
|
| 543 |
|
|
walk(tree(mkop(RET,p->type), p->type, p, NULL), 0, 0);
|
| 544 |
|
|
}
|
| 545 |
|
|
void definelab(int lab) {
|
| 546 |
|
|
Code cp;
|
| 547 |
|
|
Symbol p = findlabel(lab);
|
| 548 |
|
|
|
| 549 |
|
|
assert(lab);
|
| 550 |
|
|
walk(NULL, 0, 0);
|
| 551 |
|
|
code(Label)->u.forest = newnode(LABEL+V, NULL, NULL, p);
|
| 552 |
|
|
for (cp = codelist->prev; cp->kind <= Label; )
|
| 553 |
|
|
cp = cp->prev;
|
| 554 |
|
|
while ( cp->kind == Jump
|
| 555 |
|
|
&& cp->u.forest->kids[0]
|
| 556 |
|
|
&& specific(cp->u.forest->kids[0]->op) == ADDRG+P
|
| 557 |
|
|
&& cp->u.forest->kids[0]->syms[0] == p) {
|
| 558 |
|
|
assert(cp->u.forest->kids[0]->syms[0]->u.l.label == lab);
|
| 559 |
|
|
p->ref--;
|
| 560 |
|
|
assert(cp->next);
|
| 561 |
|
|
assert(cp->prev);
|
| 562 |
|
|
cp->prev->next = cp->next;
|
| 563 |
|
|
cp->next->prev = cp->prev;
|
| 564 |
|
|
cp = cp->prev;
|
| 565 |
|
|
while (cp->kind <= Label)
|
| 566 |
|
|
cp = cp->prev;
|
| 567 |
|
|
}
|
| 568 |
|
|
}
|
| 569 |
|
|
Node jump(int lab) {
|
| 570 |
|
|
Symbol p = findlabel(lab);
|
| 571 |
|
|
|
| 572 |
|
|
p->ref++;
|
| 573 |
|
|
return newnode(JUMP+V, newnode(ADDRG+ttob(voidptype), NULL, NULL, p),
|
| 574 |
|
|
NULL, NULL);
|
| 575 |
|
|
}
|
| 576 |
|
|
void branch(int lab) {
|
| 577 |
|
|
Code cp;
|
| 578 |
|
|
Symbol p = findlabel(lab);
|
| 579 |
|
|
|
| 580 |
|
|
assert(lab);
|
| 581 |
|
|
walk(NULL, 0, 0);
|
| 582 |
|
|
code(Label)->u.forest = jump(lab);
|
| 583 |
|
|
for (cp = codelist->prev; cp->kind < Label; )
|
| 584 |
|
|
cp = cp->prev;
|
| 585 |
|
|
while ( cp->kind == Label
|
| 586 |
|
|
&& cp->u.forest->op == LABEL+V
|
| 587 |
|
|
&& !equal(cp->u.forest->syms[0], p)) {
|
| 588 |
|
|
equatelab(cp->u.forest->syms[0], p);
|
| 589 |
|
|
assert(cp->next);
|
| 590 |
|
|
assert(cp->prev);
|
| 591 |
|
|
cp->prev->next = cp->next;
|
| 592 |
|
|
cp->next->prev = cp->prev;
|
| 593 |
|
|
cp = cp->prev;
|
| 594 |
|
|
while (cp->kind < Label)
|
| 595 |
|
|
cp = cp->prev;
|
| 596 |
|
|
}
|
| 597 |
|
|
if (cp->kind == Jump || cp->kind == Switch) {
|
| 598 |
|
|
p->ref--;
|
| 599 |
|
|
codelist->prev->next = NULL;
|
| 600 |
|
|
codelist = codelist->prev;
|
| 601 |
|
|
} else {
|
| 602 |
|
|
codelist->kind = Jump;
|
| 603 |
|
|
if (cp->kind == Label
|
| 604 |
|
|
&& cp->u.forest->op == LABEL+V
|
| 605 |
|
|
&& equal(cp->u.forest->syms[0], p))
|
| 606 |
|
|
warning("source code specifies an infinite loop\n");
|
| 607 |
|
|
}
|
| 608 |
|
|
}
|
| 609 |
|
|
void equatelab(Symbol old, Symbol new) {
|
| 610 |
|
|
assert(old->u.l.equatedto == NULL);
|
| 611 |
|
|
old->u.l.equatedto = new;
|
| 612 |
|
|
new->ref++;
|
| 613 |
|
|
}
|
| 614 |
|
|
static int equal(Symbol lprime, Symbol dst) {
|
| 615 |
|
|
assert(dst && lprime);
|
| 616 |
|
|
for ( ; dst; dst = dst->u.l.equatedto)
|
| 617 |
|
|
if (lprime == dst)
|
| 618 |
|
|
return 1;
|
| 619 |
|
|
return 0;
|
| 620 |
|
|
}
|
| 621 |
|
|
/* dostmt - do statement while ( expression ) */
|
| 622 |
|
|
static void dostmt(int lab, Swtch swp, int lev) {
|
| 623 |
|
|
refinc *= 10.0;
|
| 624 |
|
|
t = gettok();
|
| 625 |
|
|
definelab(lab);
|
| 626 |
|
|
statement(lab, swp, lev);
|
| 627 |
|
|
definelab(lab + 1);
|
| 628 |
|
|
expect(WHILE);
|
| 629 |
|
|
expect('(');
|
| 630 |
|
|
definept(NULL);
|
| 631 |
|
|
walk(conditional(')'), lab, 0);
|
| 632 |
|
|
if (findlabel(lab + 2)->ref)
|
| 633 |
|
|
definelab(lab + 2);
|
| 634 |
|
|
}
|
| 635 |
|
|
|
| 636 |
|
|
/* foldcond - check if initial test in for(e1;e2;e3) S is necessary */
|
| 637 |
|
|
static int foldcond(Tree e1, Tree e2) {
|
| 638 |
|
|
int op = generic(e2->op);
|
| 639 |
|
|
Symbol v;
|
| 640 |
|
|
|
| 641 |
|
|
if (e1 == 0 || e2 == 0)
|
| 642 |
|
|
return 0;
|
| 643 |
|
|
if (generic(e1->op) == ASGN && isaddrop(e1->kids[0]->op)
|
| 644 |
|
|
&& generic(e1->kids[1]->op) == CNST) {
|
| 645 |
|
|
v = e1->kids[0]->u.sym;
|
| 646 |
|
|
e1 = e1->kids[1];
|
| 647 |
|
|
} else
|
| 648 |
|
|
return 0;
|
| 649 |
|
|
if ((op==LE || op==LT || op==EQ || op==NE || op==GT || op==GE)
|
| 650 |
|
|
&& generic(e2->kids[0]->op) == INDIR
|
| 651 |
|
|
&& e2->kids[0]->kids[0]->u.sym == v
|
| 652 |
|
|
&& e2->kids[1]->op == e1->op) {
|
| 653 |
|
|
e1 = simplify(op, e2->type, e1, e2->kids[1]);
|
| 654 |
|
|
if (e1->op == CNST+I)
|
| 655 |
|
|
return e1->u.v.i;
|
| 656 |
|
|
}
|
| 657 |
|
|
return 0;
|
| 658 |
|
|
}
|
| 659 |
|
|
|
| 660 |
|
|
/* localaddr - returns q if p yields the address of local/parameter q; otherwise returns 0 */
|
| 661 |
|
|
static Symbol localaddr(Tree p) {
|
| 662 |
|
|
if (p == NULL)
|
| 663 |
|
|
return NULL;
|
| 664 |
|
|
switch (generic(p->op)) {
|
| 665 |
|
|
case INDIR: case CALL: case ARG:
|
| 666 |
|
|
return NULL;
|
| 667 |
|
|
case ADDRL: case ADDRF:
|
| 668 |
|
|
return p->u.sym;
|
| 669 |
|
|
case RIGHT: case ASGN:
|
| 670 |
|
|
if (p->kids[1])
|
| 671 |
|
|
return localaddr(p->kids[1]);
|
| 672 |
|
|
return localaddr(p->kids[0]);
|
| 673 |
|
|
case COND: {
|
| 674 |
|
|
Symbol q;
|
| 675 |
|
|
assert(p->kids[1] && p->kids[1]->op == RIGHT);
|
| 676 |
|
|
if ((q = localaddr(p->kids[1]->kids[0])) != NULL)
|
| 677 |
|
|
return q;
|
| 678 |
|
|
return localaddr(p->kids[1]->kids[1]);
|
| 679 |
|
|
}
|
| 680 |
|
|
default: {
|
| 681 |
|
|
Symbol q;
|
| 682 |
|
|
if (p->kids[0] && (q = localaddr(p->kids[0])) != NULL)
|
| 683 |
|
|
return q;
|
| 684 |
|
|
return localaddr(p->kids[1]);
|
| 685 |
|
|
}
|
| 686 |
|
|
}
|
| 687 |
|
|
}
|
| 688 |
|
|
|
| 689 |
|
|
/* whilestmt - while ( expression ) statement */
|
| 690 |
|
|
static void whilestmt(int lab, Swtch swp, int lev) {
|
| 691 |
|
|
Coordinate pt;
|
| 692 |
|
|
Tree e;
|
| 693 |
|
|
|
| 694 |
|
|
refinc *= 10.0;
|
| 695 |
|
|
t = gettok();
|
| 696 |
|
|
expect('(');
|
| 697 |
|
|
walk(NULL, 0, 0);
|
| 698 |
|
|
pt = src;
|
| 699 |
|
|
e = texpr(conditional, ')', FUNC);
|
| 700 |
|
|
branch(lab + 1);
|
| 701 |
|
|
definelab(lab);
|
| 702 |
|
|
statement(lab, swp, lev);
|
| 703 |
|
|
definelab(lab + 1);
|
| 704 |
|
|
definept(&pt);
|
| 705 |
|
|
walk(e, lab, 0);
|
| 706 |
|
|
if (findlabel(lab + 2)->ref)
|
| 707 |
|
|
definelab(lab + 2);
|
| 708 |
|
|
}
|
