499 lines
7 KiB
Plaintext
499 lines
7 KiB
Plaintext
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/* STATEMENT SYNTAX PARSER */
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{
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#include <em.h>
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#include "lint.h"
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#include "debug.h"
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#include "botch_free.h"
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#include "arith.h"
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#include "LLlex.h"
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#include "type.h"
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#include "idf.h"
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#include "label.h"
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#include "expr.h"
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#include "code.h"
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#include "stack.h"
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#include "def.h"
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#ifdef LINT
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#include "l_lint.h"
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#include "l_state.h"
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#endif LINT
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extern int level;
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}
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/* Each statement construction is stacked in order to trace a
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statement to such a construction. Example: a case statement should
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be recognized as a piece of the most enclosing switch statement.
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*/
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/* 9 */
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statement
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{
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#ifdef LINT
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lint_statement();
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#endif LINT
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}
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:
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%if (AHEAD != ':')
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expression_statement
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label ':' statement
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compound_statement
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if_statement
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while_statement
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do_statement
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for_statement
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switch_statement
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case_statement
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default_statement
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BREAK
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{
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code_break();
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#ifdef LINT
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lint_break_stmt();
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#endif LINT
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}
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';'
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CONTINUE
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{
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code_continue();
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#ifdef LINT
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lint_continue_stmt();
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#endif LINT
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}
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';'
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return_statement
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jump
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';'
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asm_statement
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;
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expression_statement
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{ struct expr *expr;
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}
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:
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expression(&expr)
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';'
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{
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#ifdef DEBUG
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print_expr("expression_statement", expr);
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#endif DEBUG
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code_expr(expr, RVAL, FALSE, NO_LABEL, NO_LABEL);
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free_expression(expr);
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}
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;
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label
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{ struct idf *idf;
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}
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:
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identifier(&idf)
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{
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/* This allows the following absurd case:
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typedef int grz;
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main() {
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grz: printf("A labelled statement\n");
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}
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*/
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#ifdef LINT
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lint_label();
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#endif LINT
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define_label(idf);
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C_df_ilb((label)idf->id_def->df_address);
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}
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;
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if_statement
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{
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struct expr *expr;
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label l_true = text_label();
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label l_false = text_label();
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label l_end = text_label();
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}
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:
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IF
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'('
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expression(&expr)
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{
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opnd2test(&expr, IF);
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if (is_cp_cst(expr)) {
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/* The comparison has been optimized
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to a 0 or 1.
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*/
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#ifdef LINT
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hwarning("condition in if is constant");
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#endif LINT
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if (expr->VL_VALUE == (arith)0) {
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C_bra(l_false);
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}
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/* else fall through */
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}
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else {
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code_expr(expr, RVAL, TRUE, l_true, l_false);
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C_df_ilb(l_true);
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}
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free_expression(expr);
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#ifdef LINT
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start_if_part();
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#endif LINT
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}
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')'
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statement
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[%prefer
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ELSE
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{
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#ifdef LINT
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start_else_part();
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#endif LINT
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C_bra(l_end);
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C_df_ilb(l_false);
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}
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statement
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{ C_df_ilb(l_end);
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#ifdef LINT
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end_if_else_stmt();
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#endif LINT
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}
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empty
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{ C_df_ilb(l_false);
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#ifdef LINT
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end_if_stmt();
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#endif LINT
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}
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]
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;
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while_statement
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{
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struct expr *expr;
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label l_break = text_label();
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label l_continue = text_label();
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label l_body = text_label();
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}
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:
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WHILE
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{
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stack_stmt(l_break, l_continue);
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C_df_ilb(l_continue);
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}
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'('
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expression(&expr)
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{
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opnd2test(&expr, WHILE);
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if (is_cp_cst(expr)) {
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if (expr->VL_VALUE == (arith)0) {
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C_bra(l_break);
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}
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#ifdef LINT
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start_loop_stmt(WHILE, 1,
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expr->VL_VALUE != (arith)0);
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#endif LINT
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}
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else {
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code_expr(expr, RVAL, TRUE, l_body, l_break);
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C_df_ilb(l_body);
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#ifdef LINT
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start_loop_stmt(WHILE, 0, 0);
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#endif LINT
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}
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}
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')'
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statement
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{
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C_bra(l_continue);
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C_df_ilb(l_break);
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unstack_stmt();
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free_expression(expr);
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#ifdef LINT
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end_loop_stmt();
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#endif LINT
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}
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;
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do_statement
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{ struct expr *expr;
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label l_break = text_label();
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label l_continue = text_label();
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label l_body = text_label();
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}
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:
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DO
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{ C_df_ilb(l_body);
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stack_stmt(l_break, l_continue);
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#ifdef LINT
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start_loop_stmt(DO, 1, 1);
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#endif LINT
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}
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statement
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WHILE
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'('
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{ C_df_ilb(l_continue);
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}
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expression(&expr)
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{
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opnd2test(&expr, WHILE);
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if (is_cp_cst(expr)) {
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if (expr->VL_VALUE == (arith)1) {
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C_bra(l_body);
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}
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#ifdef LINT
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end_do_stmt(1, expr->VL_VALUE != (arith)0);
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#endif LINT
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}
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else {
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code_expr(expr, RVAL, TRUE, l_body, l_break);
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#ifdef LINT
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end_do_stmt(0, 0);
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#endif LINT
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}
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C_df_ilb(l_break);
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}
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')'
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';'
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{
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unstack_stmt();
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free_expression(expr);
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}
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;
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for_statement
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{ struct expr *e_init = 0, *e_test = 0, *e_incr = 0;
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label l_break = text_label();
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label l_continue = text_label();
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label l_body = text_label();
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label l_test = text_label();
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#ifdef LINT
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int const = 1, cond = 1; /* the default case */
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#endif LINT
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}
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:
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FOR
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{ stack_stmt(l_break, l_continue);
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}
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'('
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[
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expression(&e_init)
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{ code_expr(e_init, RVAL, FALSE, NO_LABEL, NO_LABEL);
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}
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]?
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';'
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{ C_df_ilb(l_test);
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}
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[
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expression(&e_test)
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{
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opnd2test(&e_test, FOR);
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if (is_cp_cst(e_test)) {
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if (e_test->VL_VALUE == (arith)0) {
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C_bra(l_break);
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}
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#ifdef LINT
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const = 1,
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cond = e_test->VL_VALUE != (arith)0;
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#endif LINT
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}
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else {
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code_expr(e_test, RVAL, TRUE, l_body, l_break);
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C_df_ilb(l_body);
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#ifdef LINT
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const = 0, cond = 0;
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#endif LINT
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}
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}
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]?
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';'
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expression(&e_incr)?
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')'
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{
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#ifdef LINT
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start_loop_stmt(FOR, const, cond);
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#endif LINT
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}
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statement
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{
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#ifdef LINT
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end_loop_stmt();
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#endif LINT
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C_df_ilb(l_continue);
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if (e_incr)
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code_expr(e_incr, RVAL, FALSE,
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NO_LABEL, NO_LABEL);
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C_bra(l_test);
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C_df_ilb(l_break);
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unstack_stmt();
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free_expression(e_init);
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free_expression(e_test);
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free_expression(e_incr);
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}
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;
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switch_statement
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{
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struct expr *expr;
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}
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:
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SWITCH
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'('
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expression(&expr)
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{
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code_startswitch(&expr);
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#ifdef LINT
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start_switch_part();
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/* the following is a trick to detect a constant
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* expression in a switch
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*/
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opnd2test(&expr, SWITCH);
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if (is_cp_cst(expr))
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hwarning("switch value is constant");
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#endif LINT
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}
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')'
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statement
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{
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#ifdef LINT
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end_switch_stmt();
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#endif LINT
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code_endswitch();
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free_expression(expr);
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}
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;
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case_statement
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{
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struct expr *expr;
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}
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:
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CASE
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constant_expression(&expr)
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{
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#ifdef LINT
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lint_case_stmt(0);
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#endif LINT
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code_case(expr);
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free_expression(expr);
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}
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':'
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statement
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;
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default_statement
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:
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DEFAULT
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{
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#ifdef LINT
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lint_case_stmt(1);
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#endif LINT
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code_default();
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}
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':'
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statement
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;
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return_statement
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{ struct expr *expr = 0;
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}
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:
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RETURN
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[
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expression(&expr)
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{
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#ifdef LINT
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lint_ret_conv(expr->ex_type);
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#endif LINT
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do_return_expr(expr);
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free_expression(expr);
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#ifdef LINT
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lint_return_stmt(1);
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#endif LINT
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}
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empty
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{
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do_return();
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#ifdef LINT
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lint_return_stmt(0);
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#endif LINT
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}
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]
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';'
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;
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jump
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{ struct idf *idf;
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}
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:
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GOTO
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identifier(&idf)
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';'
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{
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apply_label(idf);
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C_bra((label)idf->id_def->df_address);
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#ifdef LINT
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lint_jump_stmt(idf);
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#endif LINT
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}
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;
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compound_statement:
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'{'
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{
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stack_level();
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}
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[%while ((DOT != IDENTIFIER && AHEAD != ':') ||
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(DOT == IDENTIFIER && AHEAD == IDENTIFIER))
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/* >>> conflict on TYPE_IDENTIFIER, IDENTIFIER */
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declaration
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]*
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[%persistent
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statement
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]*
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'}'
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{
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unstack_level();
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}
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;
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asm_statement
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{ char *asm_bts;
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int asm_len;
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}
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:
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ASM
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'('
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STRING
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{ asm_bts = dot.tk_bts;
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asm_len = dot.tk_len;
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}
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')'
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';'
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{ code_asm(asm_bts, asm_len);
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}
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;
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