optm.c (1172B)
1 #include <stddef.h> 2 3 #include <scc/scc.h> 4 5 #include "../../cc2.h" 6 7 Node * 8 optm_dep(Node *np) 9 { 10 int op = np->op; 11 Node *p, *dst, *next = np->next; 12 Symbol *sym, *osym; 13 14 switch (op) { 15 case OEFUN: 16 /* 17 * In QBE we need at the end of a basic block 18 * a jump, so we have to ensure that the last 19 * statement of the function is a ret, a jmp 20 * or a branch. In the same way, QBE does 21 * not accept labels at the end of a function 22 * (ONOP is used for labels) so we have to add 23 * a ret there, and in the case of branches 24 * we need a label for the next statement 25 */ 26 op = (np->prev) ? np->prev->op : 0; 27 if (!op || op == ONOP || op == OBRANCH || (op != ORET && op != OJMP)) 28 addstmt(node(ORET), KEEPCUR); 29 break; 30 case OBRANCH: 31 if (!next->label) { 32 sym = getsym(TMPSYM); 33 sym->kind = SLABEL; 34 next->label = sym; 35 } 36 case OJMP: 37 for (;;) { 38 dst = np->u.sym->u.stmt; 39 if (dst->op != OJMP) 40 break; 41 np->u.sym = dst->u.sym; 42 } 43 for (p = np->next; p; p = p->next) { 44 if (p == dst) 45 return NULL; 46 if (p->op == ONOP || 47 p->op == OBLOOP || 48 p->op == OELOOP) { 49 continue; 50 } 51 break; 52 } 53 break; 54 } 55 return np; 56 }