《编译原理》上课笔记

2015年03月30日
课本P24 P226 P259(左侧，7-1图)

1.外部声明 external-declaration
	external int a;
	int b;
	void f(){}

2.ucc\examples\sc\decl.c
课本P24
     Declaration   ----->    int Declarator
     Declarator   ----->   * Declarator  | PostfixDeclarator
				------------>D = {PD,*PD,**PD,***PD,.....}
     PostfixDeclarator ---> DirectDeclarator | PostfixDeclarator [num]
                          | PostfixDeclarator (ParameterList)
				------------>PD{DD,DD[num],DD(void),
						DD[num][num],DD(void)(void),
						DD[num](void),DD(void)[num],
						........
						}
     ParameterList --->  int |  ParameterList , int
     DirectDeclarator ----->  id  | (Declarator)

3.P226"类型表达式"
	int  --操作数
	【运算符】：*  --指针类型,[]  --数组类型,()  --函数类型

	3.1
	指针的数组：int *arr[4];          数组的指针：int(*ptr)[4];
	typedef int* INTPIR		  typedef int ARRAY[4]
	INTPIR arr[4];			  ARRAY[4] *prt;

4.P259
代码区
静态区	【编译时】（全局变量、static变量、常量）
堆区	【运行时】（new，malloc）
空闲内存【运行时】
栈区	【运行时】（局部，形参）

	4.1变参
	printf("%d",a);
	printf("%d %d",a,b);
				printf(const char*fmt, ...);

	4.2.13.png（C语言变量布局）
	匿名参数
	无名参数----->参数提升
	char，short->int
	float      ->double

Stmt.c

2015年03月16日
分析器的算法：(ucc/examples/sc/Expr.c)

1.PrimaryExpression -----> id | num | (Expression)

------PE--->-----
	 |	|
	 |	|
	 |     * /
	 |	|
	 ---PE<--
void PrimaryExpression (void){
	if(CurToken == ID)
		NEXT_TOKEN;
	else if((CurToken == NUM)
		NEXT_TOKEN;
	else if((CurToken == LP){
		NEXT_TOKEN;
		if((CurToken == RP)
			NEXT_TOKEN;
	}
	else
		error("（ is missed.");

}

2."左结合"
MultiplicativeExpression -----> PrimaryExpression
MultiplicativeExpression -----> MultiplicativeExpression * PrimaryExpression
MultiplicativeExpression -----> MultiplicativeExpression / PrimaryExpression

void MultiplicativeExpression (void){
	PrimaryExpression ();
	while(CurToken == MUL | CurToken == DIV){
		NEXT_TOKEN;
		PrimaryExpression();
	}
}

3.E = {T,T+T,...}
	= T{e,+T,+T+T,...}
	-> T E‘
		E‘ -> e
		   -> +T E‘
void E‘(void){
	if(CurrentToken == +){
		NEXT_TOKEN;
		T();E‘();
	}else{
	}
}

4.“右结合”

ME-> PE  ME‘
ME‘->e(空)
   ->*|/ ME

void MultiplicativeExpression (void){
	PrimaryExpression ();
	if(CurToken == MUL | CurToken == DIV){
		NEXT_TOKEN;
		MultiplicativeExpression();
	}else{
	}
}

5.VisitArithmeticNode()
(a+b)*c

		t1
		*

	t0		c
	+
a		b

中间代码生成：
t0 = a+b;
t1 = t0+c;

6.int(*f(int,int,int))[4]

eg.int (*arr)[4]

typedef int ARRAY[4]
ARRAY *f(int,int,int)

Expr.c

2015年03月22日课本P241
1.S->if(B)S1

if(!B)goto label0;
	S1
label0:

2.if(B)S1 else S2

if(!B)goto label0;
	S1
	goto label1;
label0:S2
	goto label1;
label1:

3.while(B) S1
label0:
	if(!B)goto label1;
	S1
	goto label0;
label1:

4.实验课自己写do...while();语句   ?????

5.if语句
kids[0]->label0
kids[1]->label1
expr->expression
thenStmt->then语句
elseStmt->else语句
next
astStmtNode

课本P129
6.VisitStatementNode->if(c) a=f;else b=k;

kids[0]->label0
kids[1]->label1
expr->c
thenStmt->a=f;
elseStmt->b=k;

7.ExpressionStatement(void){
}				->		a=3+5;

kids[0]->a
expr->   +
       3   5

8.Compund语句
------    ------
|    |	->|    |
------	  ------..........
|next|--  |next|
FIRST(a)首符号的集合

9.linux系统下 make 的结果：
[email protected]:~$ cd src/ucc/examples/sc
[email protected]:~/src/ucc/examples/sc$ make
ucc -o sc lex.c expr.c error.c decl.c stmt.c main.c
cat demo.c
{
	int (*f(int,int,int))[4];
	int (*(*fp2)(int,int,int))(int);
	if(c)
		a = f;
	else{
		b = k;
	}

	while(c){
		while(d){
			if(e){
				d = d - 1;
			}
		}
		c = c - 1;
	}
}

./sc < demo.c
f is:  function(int,int,int) which returns pointer to array[4] of int
fp2 is:  pointer to function(int,int,int) which returns pointer to function(int) which returns int
	if(!c) goto Label_0
	a = f
	goto Label_1
Label_0:
	b = k
Label_1:
Label_2:
	if(!c) goto Label_6
Label_3:
	if(!d) goto Label_5
	if(!e) goto Label_4
	t0 = d - 1
	d = t0
Label_4:
	goto Label_3
Label_5:
	t1 = c - 1
	c = t1
	goto Label_2
Label_6: