c.y

C编译器,在VC6.0环境下开发

				if ( sg_parameter_list )
				// means this compound statement belong to a function, so...
				// of course, if sg_parameter_list is NULL it also maybe a
				// compound statement belong to a function because the parameters
				// is void , heihei....
				{
					add_symbol_list_to_current_symtab(sg_parameter_list);
					sg_parameter_list = NULL;
				}
			}
			statement_list oRC
			{
				PARSE_INFO("statement_list oRC");
				del_compound_symtab();
			}
		|	oLC declaration_list 
			{
				PARSE_INFO("compound_statement :oLC declaration_list ")

				if ( sg_parameter_list )
				// means this compound statement belong to a function, so...
				// of course, if sg_parameter_list is NULL it also maybe a
				// compound statement belong to a function because the parameters
				// is void , heihei....
				{
					add_symbol_list_to_current_symtab( sg_parameter_list );
					sg_parameter_list = NULL;
				}

				gen_var_assign_init($2);
			}
			oRC
			{
				PARSE_INFO("oRC");
				yyerror("waring : compound statement has only declaration, no statements");
				del_compound_symtab();
			}
		|	oLC oRC
			{
				PARSE_INFO("compound_statement :oLC oRC")

				if ( sg_parameter_list )
				// means this compound statement belong to a function, so...
				// of course, if sg_parameter_list is NULL it also maybe a
				// compound statement belong to a function because the parameters
				// is void , heihei....
				{
					add_symbol_list_to_current_symtab( sg_parameter_list );
					sg_parameter_list = NULL;
				}

				yyerror("warning : compound statement is empty");
				del_compound_symtab();
			}
		;

statement_list
		:	statement
			{
				PARSE_INFO("statement_list :statement")
			}
		|	statement_list statement
			{
				PARSE_INFO("statement_list :statement_list statement")
			}
		;

selection_statement
		:	kIF oLP expression oRP 
			{
				char	lb_else[LABEL_LEN];

				PARSE_INFO("selection_statement :kIF oLP expression ")
				if ( !$3 )
				{
					yyerror("'if' expression can't be empty");
					user_exit(1);
				}
				// mov	ax,	expression
				gen_mov_value_to_reg($3, "ax");
				// or	ax,	ax
				gen_or("ax", "ax");

				strcpy(lb_else, get_a_label());
				// jz	lab_else
				gen_jump("jz", lb_else);
				push_label(lb_else);
			}
			statement 
			{
				char	lb_end[LABEL_LEN];

				PARSE_INFO("oRP statement ")
				strcpy(lb_end, get_a_label());
				// jmp lab_end
				gen_jump("jmp", lb_end);
				// lab_else:
				gen_label(pop_label());
				push_label(lb_end);
			}
			else_clause
			{
				PARSE_INFO("else_clause")
				// lab_end:
				gen_label(pop_label());
			}
		|	kSWITCH oLP expression oRP 
			{
				symbol	*sw;
				char	lab_start[LABEL_LEN];

				PARSE_INFO("selection_statement :kSWITCH oLP expression oRP ")
				if ( !$3 )
				{
					yyerror("'switch' expression can't be empty");
					user_exit(1);
				}

				sw = new_symbol();
				// get end label
				strcpy(sw->rname, get_a_label());

				// get start lab
				strcpy(lab_start, get_a_label());
				push_label(lab_start);

				push_switch(sw);

				// push break label
				push_break_label(sw->rname);

				// jmp lab_start
				gen_jump("jmp", lab_start);
			}
			statement
			{
				symbol	*sw, *df = NULL, *tmp;

				PARSE_INFO("statement")

				// pop break label
				pop_break_label();

				sw = pop_switch();
				
				// jmp lab_end
				gen_jump("jmp", sw->rname);

				// lab_start:
				gen_label(pop_label());

				// mov ax, $3
				gen_mov_value_to_reg($3, "ax");
				tmp = sw->next;

				while (tmp)
				{
					if ( !IS_DEFAULT(tmp) )
					{
						// is case
						// cmp ax, cl
						gen_cmp_cl("ax", tmp->V_I);
						// jz lab
						gen_jump("jz", tmp->rname);
					}
					else
						df = tmp;

					tmp = tmp->next;
				}
				if ( df )
				{
					// has default
					//jmp default
					gen_jump("jmp", df->rname);
				}
				// lab_end:
				gen_label(sw->rname);
				remove_symbol_list(sw);
			}
		;

else_clause
        :	kELSE statement
			{
				PARSE_INFO("else_clause :kELSE statement")
			}
        |
			{
				PARSE_INFO("else_clause :")
			}
        ;

iteration_statement
		:	kWHILE 
			{
				char	lb_start[LABEL_LEN];

				PARSE_INFO("iteration_statement :kWHILE ")
				strcpy(lb_start, get_a_label());
				// lab_start:
				gen_label(lb_start);
				push_label(lb_start);

				// set continue label
				push_continue_label(lb_start);
			}
			oLP expression oRP 
			{
				char	lb_end[LABEL_LEN];

				PARSE_INFO("oLP expression oRP ")
				if ( !$4 )
				{
					yyerror("'while' expression can't be empty");
					user_exit(1);
				}
				strcpy(lb_end, get_a_label());
								
				// mov	ax,	expression
				gen_mov_value_to_reg($4, "ax");
				// or	ax,	ax
				gen_or("ax", "ax");
				// jz	lab_end
				gen_jump("jz", lb_end);
				push_label(lb_end);

				// set break flag
				push_break_label(lb_end);
			}
			statement
			{
				char	lb_end[LABEL_LEN];
							
				PARSE_INFO("statement")

				// clear break flag
				pop_break_label();
				// clear continue label
				pop_continue_label();

				strcpy(lb_end, pop_label());
				// jmp	lab_start
				gen_jump("jmp", pop_label());
				// lab_end:
				gen_label(lb_end);
			}
		|	kDO 
			{
				char	lb_start[LABEL_LEN], lb_end[LABEL_LEN];

				PARSE_INFO("iteration_statement :kDO ")
				strcpy(lb_start, get_a_label());
				strcpy(lb_end, get_a_label());

				push_label(lb_end);

				// lab_start:
				gen_label(lb_start);
				push_label(lb_start);

				// set continue label
				push_continue_label(lb_start);
				// set break label
				push_break_label(lb_end);
			}
			statement kWHILE oLP expression oRP oSEMI
			{
				PARSE_INFO("statement kWHILE oLP expression oRP oSEMI")
				if ( !$6 )
				{
					yyerror("'do ... while' expression can't be empty");
					user_exit(1);
				}
								
				// clear break flag
				pop_break_label();
				// clear continue label
				pop_continue_label();

				// mov	ax,	expression
				gen_mov_value_to_reg($6, "ax");
				// or	ax,	ax
				gen_or("ax", "ax");
				// jnz	lab_start
				gen_jump("jnz", pop_label());

				// lab_end:
				gen_label(pop_label());
			}
		|	kFOR oLP expression oSEMI 
			{
				char	lab_start[LABEL_LEN], lab_end[LABEL_LEN];

				PARSE_INFO("iteration_statement :kFOR oLP expression oSEMI ")

				GEN_END_EXPRESS($3)

				strcpy(lab_start, get_a_label());
				strcpy(lab_end, get_a_label());
				// lab_start:
				gen_label(lab_start);

				// push continue stack
				push_continue_label(lab_start);

				// push break stack
				push_break_label(lab_end);
			}
			expression oSEMI 
			{
				char	lab_body[LABEL_LEN], lab_step[LABEL_LEN];

				PARSE_INFO("expression oSEMI ")
				strcpy(lab_body, get_a_label());
				strcpy(lab_step, get_a_label());

				if ( $6 )
				{
					// mov ax, $6
					gen_mov_value_to_reg($6, "ax");
					// or ax, ax
					gen_or("ax", "ax");
					// jz lab_end
					gen_jump("jz", get_break_stack_top());
				}

				// jmp body
				gen_jump("jmp", lab_body);
				// lab_step:
				gen_label(lab_step);

				// push label step
				push_label(lab_step);
				// push label body
				push_label(lab_body);
			}
			expression oRP 
			{
				PARSE_INFO("expression oRP ")

				GEN_END_EXPRESS($9)

				// jmp lab_start
				gen_jump("jmp", get_continue_stack_top());
				// lab_body:
				gen_label(pop_label());
			}
			statement
			{
				PARSE_INFO("statement")
				// jmp lab_step
				gen_jump("jmp", pop_label());
				// lab_end:
				gen_label(get_break_stack_top());

				// pop break stack
				pop_break_label();

				// pop continue stack
				pop_continue_label();
			}
		;

jump_statement
		:	kGOTO identifier oSEMI
			{
				symbol	*lb;

				PARSE_INFO("jump_statement :kGOTO identifier oSEMI")

				lb = search_goto_label($2);
				if ( !lb )
				{
					// the label has not be define or refernece
					// so, new symbol and add it to goto label symtab
					lb = new_symbol();
					lb->NOUN = SPEC_LABEL;
					strcpy(lb->name, $2);
					strcpy(lb->rname, get_a_label());
					lb->is_declaration = 1;
					add_goto_label(lb);
				}
				// jmp label
				gen_jump("jmp", lb->rname);
			}
		|	kCONTINUE oSEMI
			{
				char	*lb;

				PARSE_INFO("jump_statement :kCONTINUE oSEMI")
				lb = get_continue_stack_top();
				assert(lb);
				// jmp lb
				gen_jump("jmp", lb);
			}
		|	kBREAK oSEMI
			{
				char	*lb;

				PARSE_INFO("jump_statement :kBREAK oSEMI")
				lb = get_break_stack_top();
				assert(lb);
				// jmp lb
				gen_jump("jmp", lb);
			}
		|	kRETURN expression oSEMI
			{
				PARSE_INFO("jump_statement :kRETURN expression oSEMI")
				gen_return_stmt($2);
			}

expression
		:	assignment_expression
			{
				PARSE_INFO("expression :assignment_expression")
			}
		|	expression oCOMMA 
			{
				PARSE_INFO("expression :expression oCOMMA ")

				if ( !$1 )
				{
					yyerror("missing ';' before ','");
					user_exit(1);
				}
				GEN_END_EXPRESS($1)
				
				del_symbol($1);
			}
			assignment_expression
			{
				PARSE_INFO("assignment_expression")
				
				$$ = $4;
			}
		|
			{
				PARSE_INFO("expression :")
				$$ = NULL;
			}
		;

assignment_expression
		:	conditional_expression
			{
				PARSE_INFO("assignment_expression :conditional_expression")
			}
/*		|	unary_expression assignment_operator assignment_expression */
		|	unary_expression oASSIGN assignment_expression
			{
				PARSE_INFO("assignment_expression :unary_expression oASSIGN assignment_expression")
				if ( !IS_LVALUE($1) )
				{
					yyerror("'=' : left operand must be l-value");
					user_exit(1);
				}
				// mov	ax, $3
				gen_mov_value_to_reg($3, "ax");

				if ( IS_ARRAY($1) )
					gen_get_array_element($1);
				// mov	$1, ax
				gen_mov_reg_to_var("ax", $1);
				del_symbol($3);
				// set rvalue flag
				$1->is_rvalue = 1;
				if ( IS_ARRAY($1) )
				{
					// push ax
					gen_push_reg("ax");
					// set pushed flag
					$1->is_pushed = 1;
				}
				// not push, so not set pushed flag
			}
		|	unary_expression oPLUSASSIGN assignment_expression
			{
				PARSE_INFO("assignment_expression :unary_expression oPLUSASSIGN ssignment_expression")
				if ( !IS_LVALUE($1) )
				{
					yyerror("'+=' : left operand must be l-value");
					user_exit(1);
				}
				// mov	ax, $3
				gen_mov_value_to_reg($3, "ax");
				if ( IS_ARRAY($1) )
					gen_get_array_element($1);
				// add	ax, $1
				gen_add("ax", $1->rname);
				// mov	$1, ax
				gen_mov_reg_to_var("ax", $1);
				del_symbol($3);
				// set rvalue flag
				$1->is_rvalue = 1;
				if ( IS_ARRAY($1) )
				{
					// push ax
					gen_push_reg("ax");
					// set pushed flag
					$1->is_pushed = 1;
				}
				// not push, so not set pushed flag
			}
		|	unary_expression oMINUSASSIGN assignment_expression
			{
				PARSE_INFO("assignment_expression :unary_expression oMINUSASSIGN assignment_expression")
				if ( !IS_LVALUE($1) )
				{
					yyerror("'-=' : left operand must be l-value");
					user_exit(1);
				}
				// mov	dx, $3
				gen_mov_value_to_reg($3, "dx");
				// mov	ax, $1
				gen_mov_value_to_reg($1, "ax");
				// sub	ax,	dx
				gen_sub("ax", "dx");
				// mov	$1, ax
				gen_mov_reg_to_var("ax", $1);
				del_symbol($3);
				// set rvalue flag
				$1->is_rvalue = 1;
				if ( IS_ARRAY($1) )
				{
					// push ax
					gen_push_reg("ax");
					// set pushed flag
					$1->is_pushed = 1;
				}
				// not push, so not set pushed flag
			}
		|	unary_expression oMULASSIGN assignment_expression
			{
				PARSE_INFO("assignment_expression :unary_expression oMULASSIGN assignment_expression")
				if ( !IS_LVALUE($1) )
				{
					yyerror("'*=' : left operand must be l-value");
					user_exit(1);
				}
				// mov	dx, $3
				gen_mov_value_to_reg($3, "dx");
				// mov	ax, $1
				gen_mov_value_to_reg($1, "ax");
				// imul	dx
				gen_mul("dx");
				// mov	$1, ax
				gen_mov_reg_to_var("ax", $1);
				del_symbol($3);
				// set rvalue flag
				$1->is_rvalue = 1;
				if ( IS_ARRAY($1) )
				{
					// push ax
					gen_push_reg("ax");
					// set pushed flag
					$1->is_pushed = 1;
				}
				// not push, so not set pushed flag
			}
		|	unary_expression oDIVASSIGN assignment_expression
			{
				PARSE_INFO("assignment_expression :unary_expression oDIVASSIGN assignment_expression")
				if ( !IS_LVALUE($1) )
				{
					yyerror("'/=' : left operand must be l-value");
					user_exit(1);
				}
				// mov	dx, $3
				gen_mov_value_to_reg($3, "dx");
				// mov	ax, $1
				gen_mov_value_to_reg($1, "ax");
				// idiv	dx
				gen_div("dx");
				// mov	$1, ax
				gen_mov_reg_to_var("ax", $1);
				del_symbol($3);
				// set rvalue flag