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Create Symbol structure in cc2

The symbols in cc2 can have different type and different type of
class storage, so we need a structure to can store these values.

--- a/cc2/parser.c

+++ b/cc2/parser.c

@@ -8,7 +8,13 @@

 #define NR_STACKSIZ 32

 #define NR_NODEPOOL 128

 #define NR_EXPRESSIONS 64

+#define NR_SYMBOLS 1024

+typedef struct {

+	char vartype;

+	char storage;

+} Symbol;

+

 typedef struct node {

 	char op;

 	char type;

@@ -22,7 +28,7 @@

 static Node *stack[NR_STACKSIZ], **stackp = stack;

 static Node *listexp[NR_EXPRESSIONS], **listp = &listexp[0];

 static Node nodepool[NR_NODEPOOL], *newp = nodepool;

-char vars[1024];

+static Symbol symtbl[NR_SYMBOLS];

 extern void esyntax(void);

@@ -32,7 +38,7 @@

 	int i;

 	scanf("%d", &i);

-	if (i < 0 || i >= 1024)

+	if (i < 0 || i >= NR_SYMBOLS)

 		esyntax();

 	return i;

 }

@@ -86,9 +92,11 @@

 variable(char op)

 {

 	Node *np = newnode();

+	short id = getid();

 	np->op = op;

-	np->type = vars[np->u.id = getid()];

+	np->u.id = id;

+	np->type = symtbl[id].vartype;

 	np->left = np->right = NULL;

 	push(np);

 }

@@ -160,11 +168,11 @@

 static void

 declaration(char sclass)

 {

-	short id;

+	Symbol *sym = &symtbl[getid()];

-	id = getid();

 	getchar(); /* skip tab */

-	vars[id] = gettype();

+	sym->storage = sclass;

+	sym->vartype = gettype();

 	if (getchar() != '\n')

 		esyntax();

 }