ref: be7c5f83d4655f77d592b626a702dd2da07c3fb8
dir: /cc2/parser.c/
#include <ctype.h> #include <stdio.h> #include <cc.h> #include <sizes.h> #define NR_STACKSIZ 32 #define NR_NODEPOOL 128 #define NR_EXPRESSIONS 64 #define NR_SYMBOLS 1024 typedef struct { union { struct { char type; char storage; } v; struct { short addr; } l; } u; } Symbol; typedef struct node { char op; char type; union { short id; int imm; } u; struct node *left, *right; } Node; static Node *stack[NR_STACKSIZ], **stackp = stack; static Node *listexp[NR_EXPRESSIONS], **listp = &listexp[0]; static Node nodepool[NR_NODEPOOL], *newp = nodepool; static Symbol symtbl[NR_SYMBOLS]; extern void esyntax(void); static short getid(void) { int i; scanf("%d", &i); if (i < 0 || i >= NR_SYMBOLS) esyntax(); return i; } static Node * newnode(void) { if (newp == &nodepool[NR_NODEPOOL]) esyntax(); return newp++; } static void push(Node *np) { if (stackp == &stack[NR_STACKSIZ]) esyntax(); *stackp++ = np; } static Node * pop(void) { if (stackp == stack) esyntax(); return *--stackp; } static void link(Node *np) { if (listp == &listexp[NR_EXPRESSIONS]) esyntax(); *listp++ = np; } static char gettype(void) { char t; switch (t = getchar()) { case L_INT16: case L_INT8: return t; default: esyntax(); } } static void variable(char op) { Node *np = newnode(); short id = getid(); np->op = op; np->u.id = id; np->type = symtbl[id].u.v.type; np->left = np->right = NULL; push(np); } static void immediate(char op) { Node *np = newnode(); np->op = '#'; np->type = L_INT; scanf("%d", &np->u.imm); np->left = np->right = NULL; push(np); } static void operator(char op) { Node *np = newnode(); np->left = pop(); np->right = pop(); np->type = gettype(); np->op = op; push(np); } static void label(char op) { Node *np = newnode(); np->left = np->right = NULL; np->op = 'L'; push(np); } static Node * getroot(void) { Node *np = *--stackp; if (stackp != stack) esyntax(); return np; } static void (*optbl[])(char) = { ['+'] = operator, ['-'] = operator, ['*'] = operator, ['/'] = operator, ['A'] = variable, ['T'] = variable, ['G'] = variable, ['L'] = label, ['#'] = immediate, ['\177'] = NULL }; static void expression(void) { int c; void (*fun)(char); do { if (!isprint(c = getchar())) esyntax(); if ((fun = optbl[c]) == NULL) esyntax(); (*fun)(c); } while ((c = getchar()) == '\t'); if (c != '\n') esyntax(); link(getroot()); } static void declaration(char sclass) { Symbol *sym = &symtbl[getid()]; getchar(); /* skip tab */ sym->u.v.storage = sclass; sym->u.v.type = gettype(); if (getchar() != '\n') esyntax(); } static void deflabel(void) { Symbol *sym = &symtbl[getid()]; sym->u.l.addr = listp - listexp; } int parse(void) { int c; while ((c = getchar()) != EOF) { switch (c) { case '\t': expression(); break; case 'L': deflabel(); break; case 'S': /* struct */ break; case 'T': case 'A': case 'G': case 'R': declaration(c); break; default: esyntax(); break; } } }