ref: ebd2fc4782dd61da6f9d186e6a4c3131050d972e
dir: /cc1/stmt.c/
/* See LICENSE file for copyright and license details. */ static char sccsid[] = "@(#) ./cc1/stmt.c"; #include <stddef.h> #include <setjmp.h> #include <stdio.h> #include <cstd.h> #include "../inc/cc.h" #include "cc1.h" #define NEGATE 1 #define NONEGATE 0 Symbol *curfun; static void stmt(Symbol *lbreak, Symbol *lcont, Switch *lswitch); static void label(void) { Symbol *sym; switch (yytoken) { case IDEN: case TYPEIDEN: sym = lookup(NS_LABEL, yytext, ALLOC); if (sym->flags & SDEFINED) error("label '%s' already defined", yytext); if ((sym->flags & SDECLARED) == 0) sym = install(NS_LABEL, sym); sym->flags |= SDEFINED; emit(OLABEL, sym); next(); expect(':'); break; default: unexpected(); } } static void stmtexp(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Node *np; if (accept(';')) return; if (yytoken == IDEN && ahead() == ':') { label(); stmt(lbreak, lcont, lswitch); return; } np = expr(); if ((np->flags & NEFFECT) == 0) warn("expression without side effects"); emit(OEXPR, np); expect(';'); } static Node * condition(int neg) { Node *np; expect('('); np = condexpr(neg); expect(')'); return np; } static void While(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Symbol *begin; Node *np; begin = newlabel(); lcont = newlabel(); lbreak = newlabel(); expect(WHILE); np = condition(NONEGATE); emit(OJUMP, lcont); emit(OBLOOP, NULL); emit(OLABEL, begin); stmt(lbreak, lcont, lswitch); emit(OLABEL, lcont); emit(OBRANCH, begin); emit(OEXPR, np); emit(OELOOP, NULL); emit(OLABEL, lbreak); } static void For(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Symbol *begin, *cond; Node *econd, *einc; begin = newlabel(); lcont = newlabel(); cond = newlabel(); lbreak = newlabel(); pushctx(); expect(FOR); expect('('); switch (yytoken) { case TYPE: case TYPEIDEN: case TQUALIFIER: case SCLASS: decl(); break; default: emit(OEXPR, expr()); case ';': expect(';'); break; } econd = (yytoken != ';') ? condexpr(NONEGATE) : NULL; expect(';'); einc = (yytoken != ')') ? expr() : NULL; expect(')'); emit(OJUMP, cond); emit(OBLOOP, NULL); emit(OLABEL, begin); stmt(lbreak, lcont, lswitch); emit(OLABEL, lcont); emit(OEXPR, einc); emit(OLABEL, cond); emit((econd) ? OBRANCH : OJUMP, begin); emit(OEXPR, econd); emit(OELOOP, NULL); emit(OLABEL, lbreak); popctx(); } static void Dowhile(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Symbol *begin; Node *np; begin = newlabel(); lcont = newlabel(); lbreak = newlabel(); expect(DO); emit(OBLOOP, NULL); emit(OLABEL, begin); stmt(lbreak, lcont, lswitch); expect(WHILE); np = condition(NONEGATE); emit(OLABEL, lcont); emit(OBRANCH, begin); emit(OEXPR, np); emit(OELOOP, NULL); emit(OLABEL, lbreak); } static void Return(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Node *np; Type *tp = curfun->type->type; expect(RETURN); np = (yytoken != ';') ? decay(expr()) : NULL; expect(';'); if (!np) { if (tp != voidtype) warn("function returning non void returns no value"); tp = voidtype; } else if (np->type != tp) { if (tp == voidtype) warn("function returning void returns a value"); else if ((np = convert(np, tp, 0)) == NULL) errorp("incorrect type in return"); } emit(ORET, NULL); emit(OEXPR, np); } static void Break(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { expect(BREAK); if (!lbreak) { errorp("break statement not within loop or switch"); } else { emit(OJUMP, lbreak); expect(';'); } } static void Continue(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { expect(CONTINUE); if (!lcont) { errorp("continue statement not within loop"); } else { emit(OJUMP, lcont); expect(';'); } } static void Goto(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Symbol *sym; namespace = NS_LABEL; next(); namespace = NS_IDEN; if (yytoken != IDEN) unexpected(); sym = yylval.sym; if ((sym->flags & SDECLARED) == 0) sym = install(NS_LABEL, sym); sym->flags |= SUSED; emit(OJUMP, sym); next(); expect(';'); } static void Swtch(Symbol *obr, Symbol *lcont, Switch *osw) { Switch sw = {0}; Node *cond; Symbol *lbreak; expect(SWITCH); expect ('('); if ((cond = convert(expr(), inttype, 0)) == NULL) { errorp("incorrect type in switch statement"); cond = constnode(zero); } expect (')'); lbreak = newlabel(); emit(OBSWITCH, NULL); emit(OEXPR, cond); stmt(lbreak, lcont, &sw); emit(OESWITCH, lbreak); emit(OLABEL, lbreak); } static void Case(Symbol *lbreak, Symbol *lcont, Switch *sw) { Node *np; Symbol *label; expect(CASE); if ((np = constexpr()) == NULL) errorp("case label does not reduce to an integer constant"); if (!sw) { errorp("case label not within a switch statement"); } else if (sw->nr >= 0 && ++sw->nr == NR_SWITCH) { errorp("too many case labels for a switch statement"); sw->nr = -1; } expect(':'); label = newlabel(); emit(OCASE, label); emit(OEXPR, np); emit(OLABEL, label); stmt(lbreak, lcont, sw); } static void Default(Symbol *lbreak, Symbol *lcont, Switch *sw) { Symbol *label = newlabel(); if (sw->hasdef) errorp("multiple default labels in one switch"); sw->hasdef = 1; expect(DEFAULT); expect(':'); emit(ODEFAULT, label); emit(OLABEL, label); stmt(lbreak, lcont, sw); } static void If(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { Symbol *end, *lelse; Node *np; lelse = newlabel(); expect(IF); np = condition(NEGATE); emit(OBRANCH, lelse); emit(OEXPR, np); stmt(lbreak, lcont, lswitch); if (accept(ELSE)) { end = newlabel(); emit(OJUMP, end); emit(OLABEL, lelse); stmt(lbreak, lcont, lswitch); emit(OLABEL, end); } else { emit(OLABEL, lelse); } } static void blockit(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { switch (yytoken) { case TYPEIDEN: if (ahead() == ':') goto parse_stmt; /* PASSTHROUGH */ case TYPE: case TQUALIFIER: case SCLASS: decl(); return; default: parse_stmt: stmt(lbreak, lcont, lswitch); } } void compound(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { static int nested; pushctx(); expect('{'); if (nested == NR_BLOCK) error("too many nesting levels of compound statements"); ++nested; for (;;) { if (yytoken == '}') break; blockit(lbreak, lcont, lswitch); } --nested; popctx(); expect('}'); } static void stmt(Symbol *lbreak, Symbol *lcont, Switch *lswitch) { void (*fun)(Symbol *, Symbol *, Switch *); switch (yytoken) { case '{': fun = compound; break; case RETURN: fun = Return; break; case WHILE: fun = While; break; case FOR: fun = For; break; case DO: fun = Dowhile; break; case IF: fun = If; break; case BREAK: fun = Break; break; case CONTINUE: fun = Continue; break; case GOTO: fun = Goto; break; case SWITCH: fun = Swtch; break; case CASE: fun = Case; break; case DEFAULT: fun = Default; break; default: fun = stmtexp; break; } (*fun)(lbreak, lcont, lswitch); }