int temp_label(void) { static int next = 999; next += 1; return next; } void assign_loop_labels(int p, int break_lab, int continue_lab, int branch_back_lab) { // (It's really "loop and switch" due to need to handle "break" keyword) int i; int disp; int this; if ((p == -1) || (astop(p) == -1)) return; // Put source-level tests here in common code, not in code-generator where they were before. // If I can't find a way to get the source line here, maybe even move it back up to grammar.c if (astop(p) == AST_C_Continue) { if (continue_lab == -1) {fprintf(stderr, "* ERROR: continue not in a loop\n"); exit(1);} leftchild(p) = continue_lab; return; } else if (astop(p) == AST_C_Break) { if (break_lab == -1) {fprintf(stderr, "* ERROR: break not in a loop or switch\n"); exit(1);} leftchild(p) = break_lab; return; } // When a loop or switch body is found, set up the parameters // for any continues or breaks inside those statements. // Nested switch statements take priority over loops for a "break" if ((astop(p) == AST_C_While) || (astop(p) == AST_C_DoWhile)) { break_lab = nthchild(p, 2+0); continue_lab = nthchild(p, 2+1); branch_back_lab = nthchild(p, 2+2); // actually in while() it is used for the start of the code body if (break_lab == -1) nthchild(p, 2+0) = break_lab = temp_label(); if (continue_lab == -1) nthchild(p, 2+1) = continue_lab = temp_label(); if (branch_back_lab == -1) nthchild(p, 2+2) = branch_back_lab = temp_label(); // again, body_lab assign_loop_labels(rightchild(p), break_lab, continue_lab, branch_back_lab); } else if (astop(p) == AST_C_ForLoop) { break_lab = nthchild(p, 4+0); continue_lab = nthchild(p, 4+1); branch_back_lab = nthchild(p, 4+2); if (break_lab == -1) nthchild(p, 4+0) = break_lab = temp_label(); if (continue_lab == -1) nthchild(p, 4+1) = continue_lab = temp_label(); if (branch_back_lab == -1) nthchild(p, 4+2) = branch_back_lab = temp_label(); nthchild(p, 4+3) = temp_label(); // body lab assign_loop_labels(nthchild(p, 3), break_lab, continue_lab, branch_back_lab); } else if (astop(p) == AST_Switch) { int case_lab_chain; int default_lab; break_lab = nthchild(p, 2+0); // break_lab case_lab_chain = nthchild(p, 2+1); // chain of 'case ' labels default_lab = nthchild(p, 2+2); // default label. if (break_lab == -1) { nthchild(p, 2) = break_lab = temp_label(); } assign_loop_labels(rightchild(p), break_lab, continue_lab, branch_back_lab); } // recursively search for more loops and switch bodies throughout the code: disp = op[astop(p)-AST_BASE].Display_Children; this = 1<<(children(p)-1); for (i = 0; i < children(p); i++) { if ((nthchild(p, i) != -1) && (disp&this)) { assign_loop_labels(nthchild(p, i), break_lab, continue_lab, branch_back_lab); } this = this>>1; } }