ref: ce27aafc50fc22d1040d550a4105b53cf35d1bf2
dir: /cc2/symbol.c/
/* See LICENSE file for copyright and license details. */ static char sccsid[] = "@(#) ./cc2/symbol.c"; #include <limits.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "../inc/cc.h" #include "cc2.h" #define NR_SYMHASH 64 Symbol *locals; static Symbol *symtab[NR_SYMHASH], *curlocal; static int infunction; void freesym(Symbol *sym) { free(sym->name); free(sym); } void pushctx(void) { infunction = 1; } void popctx(void) { Symbol *sym, *next; infunction = 0; for (sym = locals; sym; sym = next) { next = sym->next; /* * Symbols are inserted in the hash in the inverted * order they are found in locals and it is impossible * to have a global over a local, because a local is * any symbol defined in the body of a function, * even if it has extern linkage. * For this reason when we reach a symbol in the * locals list we know that it is the head of it * collision list and we can remove it assigning * it h_next to the hash table position */ if (sym->id != TMPSYM) symtab[sym->id & NR_SYMHASH-1] = sym->h_next; freesym(sym); } curlocal = locals = NULL; } Symbol * getsym(unsigned id) { Symbol **htab, *sym; static unsigned short num; if (id >= USHRT_MAX) error(EBADID); htab = &symtab[id & NR_SYMHASH-1]; for (sym = *htab; sym; sym = sym->h_next) { if (sym->id > 0 && sym->id == id) break; } if (!sym) { sym = xcalloc(1, sizeof(*sym)); sym->id = id; if ((sym->numid = ++num) == 0) error(EIDOVER); if (infunction) { if (!locals) locals = sym; if (curlocal) curlocal->next = sym; curlocal = sym; } if (id != TMPSYM) { sym->h_next = *htab; *htab = sym; } } return sym; }