gstmt68.c

一个c compiler的source code

	for (i=0; i < switchcount; i++)
		for (j=i+1; j < switchcount; j++)
			if (switchids[j] < switchids[i]) {
				int temp = switchids[i];
				switchids[i] = switchids[j];
				switchids[j] = temp;
				temp = switchlabels[i];
				switchlabels[i] = switchlabels[j];
				switchlabels[j] = temp;
			}
	bingen(0,(switchcount)/2,switchcount,ap1,deflab,size,switchids,switchlabels,switchbinlabels);
}
void gencompactswitch(SNODE *stmt, int deflab)
/*
 * Generate a table lookup mechanism if the switch table isn't too sparse
 */
{       int             tablab,curlab,i;
        AMODE    *ap,*ap1,*ap2,*ap3;
  			long switchbottom=gswitchbottom, switchcount=gswitchcount;
			  long switchtop=gswitchtop;
  			int *switchlabels=0;
				tablab = nextlabel++;
        curlab = nextlabel++;
        initstack();
        ap = gen_expr(stmt->exp,F_DREG | F_VOL,4);
				initstack();
				if (switchbottom) {
					gen_code(op_sub,4,make_immed(switchbottom),ap);
					gen_code(op_blo,0,make_label(deflab),0);
				}
				gen_code(op_cmp,4,make_immed(switchtop-switchbottom),ap);
				gen_code(op_bhs,0,make_label(deflab),0);
				ap1= temp_addr();
				ap2 = xalloc(sizeof(AMODE));
				if (prm_rel) {
					ap2->preg = ap1->preg;
					ap2->mode = am_pcindx;
				}
				else {
					ap2->mode = am_adirect;
					if (prm_smallcode)
						ap2->preg = 2;
					else
						ap2->preg = 4;
				}
				ap2->offset = makenode(en_labcon,(char *)tablab,0);
				gen_code(op_lea,0,ap2,ap1);
				if (prm_rel || prm_smallcode)
					gen_code(op_asl,4,make_immed(1),ap);
				else
					gen_code(op_asl,4,make_immed(2),ap);
				if (prm_rel) {
					gen_code(op_add,4,ap,ap1);
					ap2->mode = am_ind;
					gen_code(op_add,2,ap2,ap1);
				}
				else {
					ap3->sreg = ap->preg;
					ap3->preg = ap1->preg;
					ap3->scale = 0;
					ap3->offset = makenode(en_icon,0,0);
					ap3->mode = am_baseindxdata;
					gen_code(op_move,4,ap3,ap1);
				}
				ap1->mode = am_ind;
				gen_code(op_jmp,0,ap1,0);

				initstack();
				gen_label(tablab);
		switchlabels = xalloc((switchtop-switchbottom) * sizeof(int));
	for (i=switchbottom; i < switchtop; i++) {
		switchlabels[i-switchbottom] = deflab;
	}
	stmt = stmt->s1;
	while (stmt) {
                if( stmt->s2 )          /* default case ? */
                        {
                        stmt->label = (SNODE *)deflab;
												diddef = TRUE;
                        }
                else
                        {
												switchlabels[(int)stmt->label-switchbottom] = curlab;
												stmt->label = (SNODE *)curlab;
                        }
                if( stmt->next != 0 )
                        curlab = nextlabel++;
                stmt = stmt->next;
                }
	for (i=0; i < switchtop-switchbottom; i++)
		if (prm_smallcode || prm_rel)
			gen_code(op_dcl,2,make_label(switchlabels[i]),0);
		else
			gen_code(op_dcl,4,make_label(switchlabels[i]),0);
}

void gencase(SNODE *stmt)
/*
 *      generate all cases for a switch statement.
 */
{       while( stmt != 0 )
                {
                gen_label((int)stmt->label);
                if( stmt->s1 != 0 )
                        {
                        genstmt(stmt->s1);
                        }
                stmt = stmt->next;
                }
}

void genxswitch(SNODE *stmt)
/*
 *      analyze and generate best switch statement.
 */
{       int     oldbreak;
	int olddiddef = diddef;
	int deflab = nextlabel++;
        oldbreak = breaklab;
        breaklab = nextlabel++;
				diddef = FALSE;
				switch (analyzeswitch(stmt)) {
  			case 2:
						genbinaryswitch(stmt,deflab);
						break;
					case 1:
						gencompactswitch(stmt,deflab);
						break;
					case 0:
						if (stmt->s1)
							stmt->s1->label = (SNODE *) nextlabel++;
						break;
				}
        gencase(stmt->s1);
        gen_label(breaklab);
				if (!diddef)
        	gen_label(deflab);
        breaklab = oldbreak;
	diddef = olddiddef;
}

void genreturn(SNODE *stmt,int flag)
/*
 *      generate a return statement.
 */
{       AMODE    *ap,*ap1,*ap2,*ap3;
				int size;
        if( stmt != 0 && stmt->exp != 0 )
        {
                initstack();
								if (currentfunc->tp->btp && currentfunc->tp->btp->type != bt_void && (currentfunc->tp->btp->type == bt_struct || currentfunc->tp->btp->type == bt_union)) {
									int lbl;
									lbl = nextlabel++;
									size = currentfunc->tp->btp->size;
  	              ap = gen_expr(stmt->exp,F_AREG | F_VOL,4);
									ap2 = xalloc(sizeof(AMODE));
									if (prm_linkreg && !currentfunc->intflag) {
										if (currentfunc->pascaldefn && currentfunc->tp->lst.head && currentfunc->tp->lst.head != (SYM *)-1) {
											ap2->preg = linkreg;
											ap2->mode = am_indx;
											ap2->offset = makenode(en_icon,(char *)(currentfunc->tp->lst.head->value.i + ((currentfunc->tp->lst.head->tp->size +3) &0xFFFFFFFCL)),0);
										}
										else {
											ap2->preg = linkreg;
											ap2->mode = am_indx;
											ap2->offset = makenode(en_icon,(char *)8,0);
										}
									}
									else if ( prm_phiform || currentfunc->intflag) {
										if (currentfunc->pascaldefn && currentfunc->tp->lst.head && currentfunc->tp->lst.head != (SYM *)-1) {
											ap2->preg = linkreg;
											ap2->mode = am_indx;
											ap2->offset = makenode(en_icon,(char *)(currentfunc->tp->lst.head->value.i + ((currentfunc->tp->lst.head->tp->size +3) &0xFFFFFFFCL)),0);
										}
										else {
								 			ap2->preg = linkreg;
											ap2->mode = am_ind;
										}
									}
									else {
										if (currentfunc->pascaldefn && currentfunc->tp->lst.head && currentfunc->tp->lst.head != (SYM *)-1) {
											ap2->preg = 7;
											ap2->mode = am_indx;
											ap2->offset = makenode(en_icon,(char *)(framedepth+stackdepth+currentfunc->tp->lst.head->value.i + ((currentfunc->tp->lst.head->tp->size+3) & 0xfffffffcL)),0);
										}
										else {
											ap2->preg = 7;
											ap2->mode = am_indx;
											ap2->offset = makenode(en_icon,(char *)(framedepth+stackdepth),0);
										}
									}
									ap3 = temp_addr();
									ap1 = temp_data();
									gen_code(op_move,4,ap2,ap3);
									ap->mode = am_ainc;
									ap3->mode = am_ainc;
									gen_code(op_move,4,make_immed(size),ap1);
									gen_label(lbl);
									gen_code(op_move,1,ap,ap3);
									gen_code(op_sub,4,make_immed(1),ap1);
									gen_code(op_bne,0,make_label(lbl),0);
									gen_code(op_move,4,ap2,makedreg(0));
									freeop(ap1);
									freeop(ap3);
									freeop(ap);
								}
								else {
									size = currentfunc->tp->btp->size;
  	              ap = gen_expr(stmt->exp,F_ALL,size);
									if (size > 4) {
      	    	      if( ap->mode != am_freg || ap->preg != 0 )
        	                gen_codef(op_fmove,size,ap,makefreg(0));
									}
            	    else
              	  		if( ap->mode != am_dreg || ap->preg != 0 )
                	        gen_code(op_move,size,ap,makedreg(0));
								}
        }
				if (flag) {
        	if( retlab != -1 )
                gen_label(retlab);
					if ((!prm_linkreg || currentfunc->intflag) && (lc_maxauto))
						if (lc_maxauto > 8) {
							AMODE *ap = xalloc(sizeof(AMODE)); 
							ap->mode = am_indx;
							ap->offset = makenode(en_icon,(char *)lc_maxauto,0);
							ap->preg = 7;
              	gen_code(op_lea,0,ap,makeareg(7));
						}
						else
             	gen_code(op_add,4,make_immed(lc_maxauto),makeareg(7));
          if( fsave_mask != 0 )
            gen_code(op_fmovem,10,pop,make_mask(fsave_mask,1,1));
          if( save_mask != 0 )
            gen_code(op_movem,4,pop,make_mask(save_mask,1,0));
					if (prm_linkreg && !currentfunc->intflag && (currentfunc->tp->lst.head && currentfunc->tp->lst.head != (SYM *)-1 || lc_maxauto)) {
						gen_code(op_unlk,0,makeareg(linkreg),0);
					}
					if (currentfunc->intflag)
           	gen_code(op_rte,0,0,0);
					else
						if (currentfunc->pascaldefn) {
							long retsize = 0;
							if (currentfunc->tp->lst.head && currentfunc->tp->lst.head != (SYM *)-1) {
								retsize = currentfunc->tp->lst.head->value.i + ((currentfunc->tp->lst.head->tp->size +3) & 0xfffffffcl);
								if (prm_linkreg)
									retsize -= 8;
							} 
							if (currentfunc->tp->btp && currentfunc->tp->btp->type != bt_void && (currentfunc->tp->btp->type == bt_struct || currentfunc->tp->btp->type == bt_union)) 
								retsize +=4;
							if (retsize) {
								if (prm_68020 || prm_68010)
									gen_code(op_rtd,0,make_immed(retsize),0);
								else {
									ap = temp_addr();
									freeop(ap);
									gen_code(op_move,4,pop,ap);
									if (retsize > 8) {
										ap1 = xalloc(sizeof(AMODE));
										ap1->mode = am_indx;
										ap1->offset = makenode(en_icon,(char *)retsize,0);
										ap1->preg = 7;
                		gen_code(op_lea,0,ap1,makeareg(7));
									}
									else
                		gen_code(op_add,4,make_immed(retsize),makeareg(7));
									ap->mode = am_ind;
									gen_code(op_jmp,0,ap,0);
								}
								return;
							}
						}
           	gen_code(op_rts,0,0,0);
        }
        else {
					if (retlab == -1)
						retlab = nextlabel++;
          gen_code(op_bra,0,make_label(retlab),0);
				}
}

void genstmt(SNODE *stmt)
/*
 *      genstmt will generate a statement and follow the next pointer
 *      until the block is generated.
 */
{
		   while( stmt != 0 )
                {
                switch( stmt->stype )
                        {
												case st_block:
																genstmt(stmt->exp);
																break;
                        case st_label:
                                gen_label((int)stmt->label);
                                break;
                        case st_goto:
                                gen_code(op_bra,0,make_label((int)stmt->label),0);
                                break;
                        case st_expr:
                                initstack();
                                gen_expr(stmt->exp,F_ALL | F_NOVALUE,
                                        natural_size(stmt->exp));
                                break;
                        case st_return:
                                genreturn(stmt,0);
                                break;
                        case st_if:
                                genif(stmt);
                                break;
                        case st_while:
                                genwhile(stmt);
                                break;
                        case st_do:
                                gendo(stmt);
                                break;
                        case st_for:
                                gen_for(stmt);
                                break;
												case st_line:
																gen_line(stmt);
																break;
                        case st_continue:
                                gen_code(op_bra,0,make_label(contlab),0);
                                break;
                        case st_break:
		 														gen_code(op_bra,0,make_label(breaklab),0);
                                break;
                        case st_switch:
                                genxswitch(stmt);
                                break;
												case st__genword:
																gen_genword(stmt);
																break;
                        default:
                                DIAG("unknown statement.");
                                break;
                        }
                stmt = stmt->next;
                }
}
#ifdef CPLUSPLUS
void scppinit(void)
/*
 * Call C++ reference variable and class initializers
 */
{
	if (!strcmp(currentfunc->name,"_main")) {
		AMODE *ap1,*ap2,*ap3,*ap4;
		int lbl = nextlabel++;
		initstack();
		ap1 = temp_addr();
		ap4 = xalloc(sizeof(AMODE));
		ap4->preg = ap1->preg;
		ap4->mode = am_ind;
		ap2 = set_symbol("CPPSTART",0);
		ap3 = set_symbol("CPPEND",0);
		gen_code(op_lea,4,ap2,ap1);
		gen_label(lbl);
		gen_code(op_move,4,ap1,push);
		gen_code(op_jsr,4,ap4,0);
		gen_code(op_move,4,pop,ap1);
		gen_code(op_add,4,make_immed(4),ap1);
		gen_code(op_cmp,4,ap3,ap1);
		gen_code(op_bhi,0,make_label(lbl),0);
		freeop(ap1);
	}
}
#endif
void genfunc(SNODE *stmt)
/*
 *      generate a function body.
 */
{       retlab = contlab = breaklab = -1;
				stackdepth = 0;
				if (stmt->stype == st_line) {
					gen_line(stmt);
					stmt = stmt->next;
				}
				gen_codelab(currentfunc);  /* name of function */
        opt1(stmt);			/* push args & Also loads link reg and subtracts SP */
#ifdef CPLUSPLUS
				if (prm_cplusplus) {
					scppinit();
				}
#endif
        genstmt(stmt);
        genreturn(0,1);
}