#include "c.h"

static char rcsid[] = "$Id: decl.nw,v 2.17 1997/05/20 21:49:29 drh Exp $";

#define add(x,n) (x > inttype->u.sym->u.limits.max.i-(n) ? (overflow=1,x) : x+(n))
#define chkoverflow(x,n) ((void)add(x,n))
#define bits2bytes(n) (((n) + 7)/8)
static int regcount;

static List autos, registers;
Symbol cfunc;           /* current function */
Symbol retv;            /* return value location for structs */

static void checkref(Symbol, void *);
static Symbol dclglobal(int, char *, Type, Coordinate *);
static Symbol dcllocal(int, char *, Type, Coordinate *);
static Symbol dclparam(int, char *, Type, Coordinate *);
static Type dclr(Type, char **, Symbol **, int);
static Type dclr1(char **, Symbol **, int);
static void decl(Symbol (*)(int, char *, Type, Coordinate *));
extern void doconst(Symbol, void *);
static void doglobal(Symbol, void *);
static void doextern(Symbol, void *);
static void exitparams(Symbol []);
static void fields(Type);
static void funcdefn(int, char *, Type, Symbol [], Coordinate);
static void initglobal(Symbol, int);
static void oldparam(Symbol, void *);
static Symbol *parameters(Type);
static Type specifier(int *);
static Type structdcl(int);
static Type tnode(int, Type);
void program(void) {
        int n;
        
        level = GLOBAL;
        for (n = 0; t != EOI; n++)
                if (kind[t] == CHAR || kind[t] == STATIC
                || t == ID || t == '*' || t == '(') {
                        decl(dclglobal);
                        deallocate(STMT);
			if (!(glevel >= 3 || xref))
			deallocate(FUNC);
                } else if (t == ';') {
                        warning("empty declaration\n");
                        t = gettok();
                } else {
                        error("unrecognized declaration\n");
                        t = gettok();
                }
        if (n == 0)
                warning("empty input file\n");
}
static Type specifier(int *sclass) {
        int cls, cons, sign, size, type, vol;
        Type ty = NULL;

        cls = vol = cons = sign = size = type = 0;
        if (sclass == NULL)
                cls = AUTO;
        for (;;) {
                int *p, tt = t;
                switch (t) {
                case AUTO:
		case REGISTER: if (level <= GLOBAL && cls == 0)
		                error("invalid use of `%k'\n", t);
		               p = &cls;  t = gettok();      break;
		case STATIC: case EXTERN:
		case TYPEDEF:  p = &cls;  t = gettok();      break;
		case CONST:    p = &cons; t = gettok();      break;
		case VOLATILE: p = &vol;  t = gettok();      break;
		case SIGNED:
		case UNSIGNED: p = &sign; t = gettok();      break;
		case LONG:
		case SHORT:    p = &size; t = gettok();      break;
		case VOID: case CHAR: case INT: case FLOAT:
		case DOUBLE:   p = &type; ty = tsym->type;
		                          t = gettok();      break;
		case ENUM:     p = &type; ty = enumdcl();    break;
		case STRUCT:
		case UNION:    p = &type; ty = structdcl(t); break;
		case ID:
		        if (istypename(t, tsym) && type == 0
		        && sign == 0 && size == 0) {
		                use(tsym, src);
		                ty = tsym->type;
		                if (isqual(ty)
		                && ty->size != ty->type->size) {
		                        ty = unqual(ty);
		                        if (isconst(tsym->type))
		                                ty = qual(CONST, ty);
		                        if (isvolatile(tsym->type))
		                                ty = qual(VOLATILE, ty);
		                        tsym->type = ty;
		                }
		                p = &type;
		                t = gettok();
		        } else
		                p = NULL;
		        break;
                default: p = NULL;
                }
                if (p == NULL)
                        break;
                if (*p)
		        error("invalid use of `%k'\n", tt);
                *p = tt;
        }
        if (sclass)
                *sclass = cls;
        if (type == 0) {
	        type = INT;
	        ty = inttype;
	}
	if (size == SHORT && type != INT
	||  size == LONG  && type != INT && type != DOUBLE
	||  sign && type != INT && type != CHAR)
	        error("invalid type specification\n");
	if (type == CHAR && sign)
	        ty = sign == UNSIGNED ? unsignedchar : signedchar;
	else if (size == SHORT)
	        ty = sign == UNSIGNED ? unsignedshort : shorttype;
	else if (size == LONG && type == DOUBLE)
	        ty = longdouble;
	else if (size == LONG)
	        ty = sign == UNSIGNED ? unsignedlong : longtype;
	else if (sign == UNSIGNED && type == INT)
	        ty = unsignedtype;
	if (cons == CONST)
	        ty = qual(CONST, ty);
	if (vol  == VOLATILE)
	        ty = qual(VOLATILE, ty);
        return ty;
}
static void decl(Symbol (*dcl)(int, char *, Type, Coordinate *)) {
        int sclass;
        Type ty, ty1;
        static char stop[] = { CHAR, STATIC, ID, 0 };

        ty = specifier(&sclass);
        if (t == ID || t == '*' || t == '(' || t == '[') {
                char *id;
                Coordinate pos;
                id = NULL;
		pos = src;
		if (level == GLOBAL) {
		        Symbol *params = NULL;
		        ty1 = dclr(ty, &id, &params, 0);
		        if (params && id && isfunc(ty1)
			    && (t == '{' || istypename(t, tsym)
			    || (kind[t] == STATIC && t != TYPEDEF))) {
		                if (sclass == TYPEDEF) {
				        error("invalid use of `typedef'\n");
				        sclass = EXTERN;
				}
				if (ty1->u.f.oldstyle)
				        exitscope();
				funcdefn(sclass, id, ty1, params, pos);
		                return;
		        } else if (params)
		                exitparams(params);
		} else
		        ty1 = dclr(ty, &id, NULL, 0);
                for (;;) {
                        if (Aflag >= 1 && !hasproto(ty1))
			        warning("missing prototype\n");
			if (id == NULL)
			        error("missing identifier\n");
			else if (sclass == TYPEDEF)
			        {
				        Symbol p = lookup(id, identifiers);
				        if (p && p->scope == level)
				                error("redeclaration of `%s'\n", id);
				        p = install(id, &identifiers, level,
				                level < LOCAL ? PERM : FUNC);
				        p->type = ty1;
				        p->sclass = TYPEDEF;
				        p->src = pos;
				}
			else
			        (void)(*dcl)(sclass, id, ty1, &pos);
                        if (t != ',')
                                break;
                        t = gettok();
                        id = NULL;
			pos = src;
			ty1 = dclr(ty, &id, NULL, 0);
                }
        } else if (ty == NULL
        || !(isenum(ty) ||
	     isstruct(ty) && (*unqual(ty)->u.sym->name < '1' || *unqual(ty)->u.sym->name > '9')))
                error("empty declaration\n");
        test(';', stop);
}
static Symbol dclglobal(int sclass, char *id, Type ty, Coordinate *pos) {
        Symbol p;

        if (sclass == 0)
	        sclass = AUTO;
	else if (sclass != EXTERN && sclass != STATIC) {
	        error("invalid storage class `%k' for `%t %s'\n",
	                sclass, ty, id);
	        sclass = AUTO;
	}
	p = lookup(id, identifiers);
	if (p && p->scope == GLOBAL) {
	        if (p->sclass != TYPEDEF && eqtype(ty, p->type, 1))
	                ty = compose(ty, p->type);
	        else
	                error("redeclaration of `%s' previously declared at %w\n", p->name, &p->src);

	        if (!isfunc(ty) && p->defined && t == '=')
	                error("redefinition of `%s' previously defined at %w\n", p->name, &p->src);

	        if (p->sclass == EXTERN && sclass == STATIC
		||  p->sclass == STATIC && sclass == AUTO
		||  p->sclass == AUTO   && sclass == STATIC)
		        warning("inconsistent linkage for `%s' previously declared at %w\n", p->name, &p->src);

	}
	if (p == NULL || p->scope != GLOBAL) {
	        p = install(id, &globals, GLOBAL, PERM);
	        p->sclass = sclass;
	        if (p->sclass != STATIC) {
	                static int nglobals;
	                nglobals++;
	                if (Aflag >= 2 && nglobals == 512)
	                        warning("more than 511 external identifiers\n");
	        }
	        (*IR->defsymbol)(p);
	} else if (p->sclass == EXTERN)
	        p->sclass = sclass;
	p->type = ty;
	p->src = *pos;
	{
	        Symbol q = lookup(p->name, externals);
	        if (q && (p->sclass == STATIC
	                  || !eqtype(p->type, q->type, 1)))
	                warning("declaration of `%s' does not match previous declaration at %w\n", p->name, &q->src);

	}
	if (t == '=' && isfunc(p->type)) {
	        error("illegal initialization for `%s'\n", p->name);
	        t = gettok();
	        initializer(p->type, 0);
	} else if (t == '=') {
	        initglobal(p, 0);
	        if (glevel > 0 && IR->stabsym) {
	                (*IR->stabsym)(p); swtoseg(p->u.seg); }
	} else if (p->sclass == STATIC && !isfunc(p->type)
	&& p->type->size == 0)
	        error("undefined size for `%t %s'\n", p->type, p->name);
        return p;
}
static void initglobal(Symbol p, int flag) {
        Type ty;

        if (t == '=' || flag) {
                if (p->sclass == STATIC) {
                        for (ty = p->type; isarray(ty); ty = ty->type)
                                ;
                        defglobal(p, isconst(ty) ? LIT : DATA);
                } else
                        defglobal(p, DATA);
                if (t == '=')
                        t = gettok();
                ty = initializer(p->type, 0);
                if (isarray(p->type) && p->type->size == 0)
                        p->type = ty;
                if (p->sclass == EXTERN)
                        p->sclass = AUTO;
        }
}
void defglobal(Symbol p, int seg) {
        p->u.seg = seg;
        swtoseg(p->u.seg);
        if (p->sclass != STATIC)
                (*IR->export)(p);
        (*IR->global)(p);
        p->defined = 1;
}

static Type dclr(Type basety, char **id, Symbol **params, int abstract) {
        Type ty = dclr1(id, params, abstract);

        for ( ; ty; ty = ty->type)
                switch (ty->op) {
                case POINTER:
                        basety = ptr(basety);
                        break;
                case FUNCTION:
                        basety = func(basety, ty->u.f.proto,
                                ty->u.f.oldstyle);
                        break;
                case ARRAY:
                        basety = array(basety, ty->size, 0);
                        break;
                case CONST: case VOLATILE:
                        basety = qual(ty->op, basety);
                        break;
                default: assert(0);
                }
        if (Aflag >= 2 && basety->size > 32767)
                warning("more than 32767 bytes in `%t'\n", basety);
        return basety;
}
static Type tnode(int op, Type type) {
        Type ty;

        NEW0(ty, STMT);
        ty->op = op;
        ty->type = type;
        return ty;
}
static Type dclr1(char **id, Symbol **params, int abstract) {
        Type ty = NULL;

        switch (t) {
        case ID:                if (id)
				        *id = token;
				else
				        error("extraneous identifier `%s'\n", token);
				t = gettok(); break;
        case '*': t = gettok(); if (t == CONST || t == VOLATILE) {
				        Type ty1;
				        ty1 = ty = tnode(t, NULL);
				        while ((t = gettok()) == CONST || t == VOLATILE)
				                ty1 = tnode(t, ty1);
				        ty->type = dclr1(id, params, abstract);
				        ty = ty1;
				} else
				        ty = dclr1(id, params, abstract);
				ty = tnode(POINTER, ty); break;
        case '(': t = gettok(); if (abstract
				&& (t == REGISTER || istypename(t, tsym) || t == ')')) {
				        Symbol *args;
				        ty = tnode(FUNCTION, ty);
				        enterscope();
					if (level > PARAM)
					        enterscope();
				        args = parameters(ty);
				        exitparams(args);
				} else {
				        ty = dclr1(id, params, abstract);
				        expect(')');
				        if (abstract && ty == NULL
				        && (id == NULL || *id == NULL))
				                return tnode(FUNCTION, NULL);
				} break;
        case '[': break;
        default:  return ty;
        }
        while (t == '(' || t == '[')
                switch (t) {
                case '(': t = gettok(); { Symbol *args;
					  ty = tnode(FUNCTION, ty);
					  enterscope();
					  if (level > PARAM)
					          enterscope();
					  args = parameters(ty);
					  if (params && *params == NULL)
					          *params = args;
					  else
					          exitparams(args);
 }
                          break;
                case '[': t = gettok(); { int n = 0;
					  if (kind[t] == ID) {
					          n = intexpr(']', 1);
					          if (n <= 0) {
					                  error("`%d' is an illegal array size\n", n);
					                  n = 1;
					          }
					  } else
					          expect(']');
					  ty = tnode(ARRAY, ty);
					  ty->size = n; } break;
                default: assert(0);
                }
        return ty;
}
static Symbol *parameters(Type fty) {
        List list = NULL;
        Symbol *params;

        if (kind[t] == STATIC || istypename(t, tsym)) {
                int n = 0;
		Type ty1 = NULL;
		for (;;) {
		        Type ty;
		        int sclass = 0;
		        char *id = NULL;
		        if (ty1 && t == ELLIPSIS) {
		                static struct symbol sentinel;
				if (sentinel.type == NULL) {
				        sentinel.type = voidtype;
				        sentinel.defined = 1;
				}
				if (ty1 == voidtype)
				        error("illegal formal parameter types\n");
				list = append(&sentinel, list);
		                t = gettok();
		                break;
		        }
		        if (!istypename(t, tsym) && t != REGISTER)
		                error("missing parameter type\n");
		        n++;
		        ty = dclr(specifier(&sclass), &id, NULL, 1);
		        if ( ty == voidtype && (ty1 || id)
			||  ty1 == voidtype)
			        error("illegal formal parameter types\n");
			if (id == NULL)
			        id = stringd(n);
			if (ty != voidtype)
			        list = append(dclparam(sclass, id, ty, &src), list);
			if (Aflag >= 1 && !hasproto(ty))
			        warning("missing prototype\n");
		        if (ty1 == NULL)
		                ty1 = ty;
		        if (t != ',')
		                break;
		        t = gettok();
		}
		fty->u.f.proto = newarray(length(list) + 1,
		        sizeof (Type *), PERM);
		params = ltov(&list, FUNC);
		for (n = 0; params[n]; n++)
		        fty->u.f.proto[n] = params[n]->type;
		fty->u.f.proto[n] = NULL;
		fty->u.f.oldstyle = 0;
        } else {
                if (t == ID)
		        for (;;) {
		                Symbol p;
		                if (t != ID) {
		                        error("expecting an identifier\n");
		                        break;
		                }
		                p = dclparam(0, token, inttype, &src);
		                p->defined = 0;
		                list = append(p, list);
		                t = gettok();
		                if (t != ',')
		                        break;
		                t = gettok();
		        }
		params = ltov(&list, FUNC);
		fty->u.f.proto = NULL;
		fty->u.f.oldstyle = 1;
        }
        if (t != ')') {
                static char stop[] = { CHAR, STATIC, IF, ')', 0 };
                expect(')');
                skipto('{', stop);
        }
        if (t == ')')
                t = gettok();
        return params;
}
static void exitparams(Symbol params[]) {
        assert(params);
        if (params[0] && !params[0]->defined)
                error("extraneous old-style parameter list\n");
        if (level > PARAM)
	        exitscope();
	exitscope();
}

static Symbol dclparam(int sclass, char *id, Type ty, Coordinate *pos) {
        Symbol p;

        if (isfunc(ty))
	        ty = ptr(ty);
	else if (isarray(ty))
	        ty = atop(ty);
	if (sclass == 0)
	        sclass = AUTO;
	else if (sclass != REGISTER) {
	        error("invalid storage class `%k' for `%t%s\n",
	                sclass, ty, stringf(id ? " %s'" : "' parameter", id));
	        sclass = AUTO;
	} else if (isvolatile(ty) || isstruct(ty)) {
	        warning("register declaration ignored for `%t%s\n",
	                ty, stringf(id ? " %s'" : "' parameter", id));
	        sclass = AUTO;
	}

	p = lookup(id, identifiers);
	if (p && p->scope == level)
	        error("duplicate declaration for `%s' previously declared at %w\n", id, &p->src);

	else
	        p = install(id, &identifiers, level, FUNC);
	p->sclass = sclass;
	p->src = *pos;
	p->type = ty;
	p->defined = 1;
	if (t == '=') {
	        error("illegal initialization for parameter `%s'\n", id);
	        t = gettok();
	        (void)expr1(0);
	}
        return p;
}
static Type structdcl(int op) {
        char *tag;
        Type ty;
        Symbol p;
        Coordinate pos;

        t = gettok();
        pos = src;
        if (t == ID) {
	        tag = token;
	        t = gettok();
	} else
	        tag = "";
	if (t == '{') {
	        static char stop[] = { IF, ',', 0 };
	        ty = newstruct(op, tag);
	        ty->u.sym->src = pos;
	        ty->u.sym->defined = 1;
	        t = gettok();
	        if (istypename(t, tsym))
	                fields(ty);
	        else
	                error("invalid %k field declarations\n", op);
	        test('}', stop);
	}
	else if (*tag && (p = lookup(tag, types)) != NULL
	&& p->type->op == op) {
	        ty = p->type;
	        if (t == ';' && p->scope < level)
	                ty = newstruct(op, tag);
	}
	else {
	        if (*tag == 0)
	                error("missing %k tag\n", op);
	        ty = newstruct(op, tag);
	}
	if (*tag && xref)
	        use(ty->u.sym, pos);
        return ty;
}
static void fields(Type ty) {
        { int n = 0;
	  while (istypename(t, tsym)) {
	          static char stop[] = { IF, CHAR, '}', 0 };
	          Type ty1 = specifier(NULL);
	          for (;;) {
	                  Field p;
	                  char *id = NULL;
	                  Type fty = dclr(ty1, &id, NULL, 0);
			  p = newfield(id, ty, fty);
			  if (Aflag >= 1 && !hasproto(p->type))
			          warning("missing prototype\n");
			  if (t == ':') {
			          if (unqual(p->type) != inttype
			          &&  unqual(p->type) != unsignedtype) {
			                  error("`%t' is an illegal bit-field type\n",
			                          p->type);
			                  p->type = inttype;
			          }
			          t = gettok();
			          p->bitsize = intexpr(0, 0);
			          if (p->bitsize > 8*inttype->size || p->bitsize < 0) {
			                  error("`%d' is an illegal bit-field size\n",
			                          p->bitsize);
			                  p->bitsize = 8*inttype->size;
			          } else if (p->bitsize == 0 && id) {
			                  warning("extraneous 0-width bit field `%t %s' ignored\n", p->type, id);

			                  p->name = stringd(genlabel(1));
			          }
			          p->lsb = 1;
			  }
			  else {
			          if (id == NULL)
			                  error("field name missing\n");
			          else if (isfunc(p->type))
			                  error("`%t' is an illegal field type\n", p->type);
			          else if (p->type->size == 0)
			                  error("undefined size for field `%t %s'\n",
			                          p->type, id);
			  }
			  if (isconst(p->type))
			          ty->u.sym->u.s.cfields = 1;
			  if (isvolatile(p->type))
			          ty->u.sym->u.s.vfields = 1;
	                  n++;
	                  if (Aflag >= 2 && n == 128)
	                          warning("more than 127 fields in `%t'\n", ty);
	                  if (t != ',')
	                          break;
	                  t = gettok();
	          }
	          test(';', stop);
	  } }
        { int bits = 0, off = 0, overflow = 0;
	  Field p, *q = &ty->u.sym->u.s.flist;
	  ty->align = IR->structmetric.align;
	  for (p = *q; p; p = p->link) {
	          int a = p->type->align ? p->type->align : 1;
		  if (p->lsb)
		          a = unsignedtype->align;
		  if (ty->op == UNION)
		          off = bits = 0;
		  else if (p->bitsize == 0 || bits == 0
		  || bits - 1 + p->bitsize > 8*unsignedtype->size) {
		          off = add(off, bits2bytes(bits-1));
		          bits = 0;
		          chkoverflow(off, a - 1);
		          off = roundup(off, a);
		  }
		  if (a > ty->align)
		          ty->align = a;
		  p->offset = off;

		  if (p->lsb) {
		          if (bits == 0)
		                  bits = 1;
		          if (IR->little_endian)
		                  p->lsb = bits;
		          else
		                  p->lsb = 8*unsignedtype->size - bits + 1
		                          - p->bitsize + 1;
		          bits += p->bitsize;
		  } else
		          off = add(off, p->type->size);
		  if (off + bits2bytes(bits-1) > ty->size)
		          ty->size = off + bits2bytes(bits-1);
	          if (p->name == NULL
	          || !('1' <= *p->name && *p->name <= '9')) {
	                  *q = p;
	                  q = &p->link;
	          }
	  }
	  *q = NULL;
	  chkoverflow(ty->size, ty->align - 1);
	  ty->size = roundup(ty->size, ty->align);
	  if (overflow) {
	          error("size of `%t' exceeds %d bytes\n", ty, inttype->u.sym->u.limits.max.i);
	          ty->size = inttype->u.sym->u.limits.max.i&(~(ty->align - 1));
	  } }
}
static void funcdefn(int sclass, char *id, Type ty, Symbol params[], Coordinate pt) {
        int i, n;
        Symbol *callee, *caller, p;
        Type rty = freturn(ty);

        if (isstruct(rty) && rty->size == 0)
	        error("illegal use of incomplete type `%t'\n", rty);
	for (n = 0; params[n]; n++)
	        ;
	if (n > 0 && params[n-1]->name == NULL)
	        params[--n] = NULL;
	if (Aflag >= 2 && n > 31)
	        warning("more than 31 parameters in function `%s'\n", id);
	if (ty->u.f.oldstyle) {
	        if (Aflag >= 1)
	                warning("old-style function definition for `%s'\n", id);
	        caller = params;
		callee = newarray(n + 1, sizeof *callee, FUNC);
		memcpy(callee, caller, (n+1)*sizeof *callee);
		enterscope();
		assert(level == PARAM);
		while (kind[t] == STATIC || istypename(t, tsym))
		        decl(dclparam);
		foreach(identifiers, PARAM, oldparam, callee);

		for (i = 0; (p = callee[i]) != NULL; i++) {
		        if (!p->defined)
		                callee[i] = dclparam(0, p->name, inttype, &p->src);
		        *caller[i] = *p;
		        caller[i]->sclass = AUTO;
		        caller[i]->type = promote(p->type);
		}
		p = lookup(id, identifiers);
		if (p && p->scope == GLOBAL && isfunc(p->type)
		&& p->type->u.f.proto) {
		        Type *proto = p->type->u.f.proto;
		        for (i = 0; caller[i] && proto[i]; i++) {
		                Type ty = unqual(proto[i]);
		                if (eqtype(isenum(ty) ? ty->type : ty,
		                        unqual(caller[i]->type), 1) == 0)
		                        break;
		                else if (isenum(ty) && !isenum(unqual(caller[i]->type)))
		                        warning("compatibility of `%t' and `%t' is compiler dependent\n",
		                                proto[i], caller[i]->type);
		        }
		        if (proto[i] || caller[i])
		                error("conflicting argument declarations for function `%s'\n", id);

		}
		else {
		        Type *proto = newarray(n + 1, sizeof *proto, PERM);
		        if (Aflag >= 1)
		                warning("missing prototype for `%s'\n", id);
		        for (i = 0; i < n; i++)
		                proto[i] = caller[i]->type;
		        proto[i] = NULL;
		        ty = func(rty, proto, 1);
		}
	} else {
	        callee = params;
		caller = newarray(n + 1, sizeof *caller, FUNC);
		for (i = 0; (p = callee[i]) != NULL && p->name; i++) {
		        NEW(caller[i], FUNC);
		        *caller[i] = *p;
		        if (isint(p->type))
		                caller[i]->type = promote(p->type);
		        caller[i]->sclass = AUTO;
		        if ('1' <= *p->name && *p->name <= '9')
		                error("missing name for parameter %d to function `%s'\n", i + 1, id);

		}
		caller[i] = NULL;
	}
	for (i = 0; (p = callee[i]) != NULL; i++)
	        if (p->type->size == 0) {
	                error("undefined size for parameter `%t %s'\n",
	                        p->type, p->name);
	                caller[i]->type = p->type = inttype;
	        }
	if (Aflag >= 2 && sclass != STATIC && strcmp(id, "main") == 0) {
	        if (ty->u.f.oldstyle)
	                warning("`%t %s()' is a non-ANSI definition\n", rty, id);
	        else if (!(rty == inttype
	                && (n == 0 && callee[0] == NULL
	                ||  n == 2 && callee[0]->type == inttype
	                && isptr(callee[1]->type) && callee[1]->type->type == ptr(chartype)
	                && !variadic(ty))))
	                warning("`%s' is a non-ANSI definition\n", typestring(ty, id));
	}
	p = lookup(id, identifiers);
	if (p && isfunc(p->type) && p->defined)
	        error("redefinition of `%s' previously defined at %w\n",
	                p->name, &p->src);
	cfunc = dclglobal(sclass, id, ty, &pt);
	cfunc->u.f.label = genlabel(1);
	cfunc->u.f.callee = callee;
	cfunc->u.f.pt = src;
	cfunc->defined = 1;
	if (xref)
	        use(cfunc, cfunc->src);
	if (Pflag)
	        printproto(cfunc, cfunc->u.f.callee);
	if (ncalled >= 0)
	        ncalled = findfunc(cfunc->name, pt.file);
	labels   = table(NULL, LABELS);
	stmtlabs = table(NULL, LABELS);
	refinc = 1.0;
	regcount = 0;
	codelist = &codehead;
	codelist->next = NULL;
	if (!IR->wants_callb && isstruct(rty))
	        retv = genident(AUTO, ptr(rty), PARAM);
	compound(0, NULL, 0);

	{
	        Code cp;
	        for (cp = codelist; cp->kind < Label; cp = cp->prev)
	                ;
	        if (cp->kind != Jump) {
	                if (rty != voidtype)
	                        warning("missing return value\n");
	                retcode(NULL);
	        }
	}
	definelab(cfunc->u.f.label);
	if (events.exit)
	        apply(events.exit, cfunc, NULL);
	walk(NULL, 0, 0);
	exitscope();
	assert(level == PARAM);
	foreach(identifiers, level, checkref, NULL);
	if (!IR->wants_callb && isstruct(rty)) {
	        Symbol *a;
	        a = newarray(n + 2, sizeof *a, FUNC);
	        a[0] = retv;
	        memcpy(&a[1], callee, (n+1)*sizeof *callee);
	        callee = a;
	        a = newarray(n + 2, sizeof *a, FUNC);
	        NEW(a[0], FUNC);
	        *a[0] = *retv;
	        memcpy(&a[1], caller, (n+1)*sizeof *callee);
	        caller = a;
	}
	if (!IR->wants_argb)
	        for (i = 0; caller[i]; i++)
	                if (isstruct(caller[i]->type)) {
	                        caller[i]->type = ptr(caller[i]->type);
	                        callee[i]->type = ptr(callee[i]->type);
	                        caller[i]->structarg = callee[i]->structarg = 1;
	                }
	if (glevel > 1) for (i = 0; callee[i]; i++) callee[i]->sclass = AUTO;
	if (cfunc->sclass != STATIC)
	        (*IR->export)(cfunc);
	if (glevel && IR->stabsym) {
	        swtoseg(CODE); (*IR->stabsym)(cfunc); }
	swtoseg(CODE);
	(*IR->function)(cfunc, caller, callee, cfunc->u.f.ncalls);
	if (glevel && IR->stabfend)
	        (*IR->stabfend)(cfunc, lineno);
	foreach(stmtlabs, LABELS, checklab, NULL);
	exitscope();
	expect('}');
	labels = stmtlabs = NULL;
	retv  = NULL;
	cfunc = NULL;
}
static void oldparam(Symbol p, void *cl) {
        int i;
        Symbol *callee = cl;

        for (i = 0; callee[i]; i++)
                if (p->name == callee[i]->name) {
                        callee[i] = p;
                        return;
                }
        error("declared parameter `%s' is missing\n", p->name);
}
void compound(int loop, struct swtch *swp, int lev) {
        Code cp;
        int nregs;

        walk(NULL, 0, 0);
        cp = code(Blockbeg);
        enterscope();
        assert(level >= LOCAL);
        if (level == LOCAL && events.entry)
                apply(events.entry, cfunc, NULL);
        definept(NULL);
        expect('{');
        autos = registers = NULL;
	if (level == LOCAL && IR->wants_callb
	&& isstruct(freturn(cfunc->type))) {
	        retv = genident(AUTO, ptr(freturn(cfunc->type)), level);
	        retv->defined = 1;
	        retv->ref = 1;
	        registers = append(retv, registers);
	}
	while (kind[t] == CHAR || kind[t] == STATIC
	|| istypename(t, tsym) && getchr() != ':')
	        decl(dcllocal);
	{
	        int i;
	        Symbol *a = ltov(&autos, STMT);
	        nregs = length(registers);
	        for (i = 0; a[i]; i++)
	                registers = append(a[i], registers);
	        cp->u.block.locals = ltov(&registers, FUNC);
	}
	if (events.blockentry)
	        apply(events.blockentry, cp->u.block.locals, NULL);
	while (kind[t] == IF || kind[t] == ID)
	        statement(loop, swp, lev);
	walk(NULL, 0, 0);
	foreach(identifiers, level, checkref, NULL);
	{
	        int i = nregs, j;
	        Symbol p;
	        for ( ; (p = cp->u.block.locals[i]) != NULL; i++) {
	                for (j = i; j > nregs
	                        && cp->u.block.locals[j-1]->ref < p->ref; j--)
	                        cp->u.block.locals[j] = cp->u.block.locals[j-1];
	                cp->u.block.locals[j] = p;
	        }
	}
	if (events.blockexit)
	        apply(events.blockexit, cp->u.block.locals, NULL);
        cp->u.block.level = level;
        cp->u.block.identifiers = identifiers;
        cp->u.block.types = types;
        code(Blockend)->u.begin = cp;
        if (reachable(Gen))
                definept(NULL);
        if (level > LOCAL) {
                exitscope();
                expect('}');
        }
}
static void checkref(Symbol p, void *cl) {
        if (p->scope >= PARAM
	&& (isvolatile(p->type) || isfunc(p->type)))
	        p->addressed = 1;
	if (Aflag >= 2 && p->defined && p->ref == 0) {
	        if (p->sclass == STATIC)
	                warning("static `%t %s' is not referenced\n",
	                        p->type, p->name);
	        else if (p->scope == PARAM)
	                warning("parameter `%t %s' is not referenced\n",
	                        p->type, p->name);
	        else if (p->scope >= LOCAL && p->sclass != EXTERN)
	                warning("local `%t %s' is not referenced\n",
	                        p->type, p->name);
	}
	if (p->sclass == AUTO
	&& (p->scope  == PARAM && regcount == 0
	 || p->scope  >= LOCAL)
	&& !p->addressed && isscalar(p->type) && p->ref >= 3.0)
	        p->sclass = REGISTER;
	if (p->scope >= LOCAL && p->sclass == EXTERN) {
	        Symbol q = lookup(p->name, externals);
	        assert(q);
	        q->ref += p->ref;
	}
	if (level == GLOBAL && p->sclass == STATIC && !p->defined
	&& isfunc(p->type) && p->ref)
	        error("undefined static `%t %s'\n", p->type, p->name);
	assert(!(level == GLOBAL && p->sclass == STATIC && !p->defined && !isfunc(p->type)));
}
static Symbol dcllocal(int sclass, char *id, Type ty, Coordinate *pos) {
        Symbol p, q;

        if (sclass == 0)
	        sclass = isfunc(ty) ? EXTERN : AUTO;
	else if (isfunc(ty) && sclass != EXTERN) {
	        error("invalid storage class `%k' for `%t %s'\n",
	                sclass, ty, id);
	        sclass = EXTERN;
	} else if (sclass == REGISTER
	&& (isvolatile(ty) || isstruct(ty) || isarray(ty))) {
	        warning("register declaration ignored for `%t %s'\n",
	                ty, id);
	        sclass = AUTO;
	}
	q = lookup(id, identifiers);
	if (q && q->scope >= level
	||  q && q->scope == PARAM && level == LOCAL)
	        if (sclass == EXTERN && q->sclass == EXTERN
	        && eqtype(q->type, ty, 1))
	                ty = compose(ty, q->type);
	        else
	                error("redeclaration of `%s' previously declared at %w\n", q->name, &q->src);

	assert(level >= LOCAL);
	p = install(id, &identifiers, level, FUNC);
	p->type = ty;
	p->sclass = sclass;
	p->src = *pos;
	switch (sclass) {
	case EXTERN:   if (q && q->scope == GLOBAL && q->sclass == STATIC) {
		               p->sclass = STATIC;
		               p->scope = GLOBAL;
		               (*IR->defsymbol)(p);
		               p->sclass = EXTERN;
		               p->scope = level;
		       } else
		               (*IR->defsymbol)(p);
		       {
		               Symbol r = lookup(id, externals);
		               if (r == NULL) {
		                       r = install(p->name, &externals, GLOBAL, PERM);
		                       r->src = p->src;
		                       r->type = p->type;
		                       r->sclass = p->sclass;
		                       q = lookup(id, globals);
		                       if (q && q->sclass != TYPEDEF && q->sclass != ENUM)
		                               r = q;
		               }
		               if (r && !eqtype(r->type, p->type, 1))
		                       warning("declaration of `%s' does not match previous declaration at %w\n", r->name, &r->src);

		       } break;
	case STATIC:   (*IR->defsymbol)(p);
		       initglobal(p, 0);
		       if (!p->defined)
		               if (p->type->size > 0) {
		                       defglobal(p, BSS);
		                       (*IR->space)(p->type->size);
		               } else
		                       error("undefined size for `%t %s'\n",
		                               p->type, p->name);
		       p->defined = 1; break;
	case REGISTER: registers = append(p, registers);
		       regcount++;
		       p->defined = 1;
 break;
	case AUTO:     autos = append(p, autos);
		       p->defined = 1; break;
	default: assert(0);
	}
	if (t == '=') {
	        Tree e;
	        if (sclass == EXTERN)
	                error("illegal initialization of `extern %s'\n", id);
	        t = gettok();
	        definept(NULL);
	        if (isscalar(p->type)
	        ||  isstruct(p->type) && t != '{') {
	                if (t == '{') {
	                        t = gettok();
	                        e = expr1(0);
	                        expect('}');
	                } else
	                        e = expr1(0);
	        } else {
	                Symbol t1;
			Type ty = p->type, ty1 = ty;
			while (isarray(ty1))
			        ty1 = ty1->type;
			if (!isconst(ty) && (!isarray(ty) || !isconst(ty1)))
			        ty = qual(CONST, ty);
			t1 = genident(STATIC, ty, GLOBAL);
			initglobal(t1, 1);
			if (isarray(p->type) && p->type->size == 0
			&& t1->type->size > 0)
			        p->type = array(p->type->type,
			                t1->type->size/t1->type->type->size, 0);
	                e = idtree(t1);
	        }
	        walk(root(asgn(p, e)), 0, 0);
	        p->ref = 1;
	}
	if (!isfunc(p->type) && p->defined && p->type->size <= 0)
	        error("undefined size for `%t %s'\n", p->type, id);
        return p;
}
void finalize(void) {
        foreach(externals,   GLOBAL,    doextern, NULL);
        foreach(identifiers, GLOBAL,    doglobal, NULL);
        foreach(identifiers, GLOBAL,    checkref, NULL);
        foreach(constants,   CONSTANTS, doconst,  NULL);
}
static void doextern(Symbol p, void *cl) {
        Symbol q = lookup(p->name, identifiers);

        if (q)
                q->ref += p->ref;
        else {
                (*IR->defsymbol)(p);
                (*IR->import)(p);
        }
}
static void doglobal(Symbol p, void *cl) {
        if (!p->defined && (p->sclass == EXTERN
        || isfunc(p->type) && p->sclass == AUTO))
                (*IR->import)(p);
        else if (!p->defined && !isfunc(p->type)
        && (p->sclass == AUTO || p->sclass == STATIC)) {
                if (isarray(p->type)
                && p->type->size == 0 && p->type->type->size > 0)
                        p->type = array(p->type->type, 1, 0);
                if (p->type->size > 0) {
                        defglobal(p, BSS);
                        (*IR->space)(p->type->size);
                } else
                        error("undefined size for `%t %s'\n",
                                p->type, p->name);
                p->defined = 1;
        }
        if (Pflag
	&& !isfunc(p->type)
	&& !p->generated && p->sclass != EXTERN)
	        printdecl(p, p->type);
}
void doconst(Symbol p, void *cl) {
        if (p->u.c.loc) {
                assert(p->u.c.loc->u.seg == 0); 
                defglobal(p->u.c.loc, LIT);
                if (isarray(p->type))
                        (*IR->defstring)(p->type->size, p->u.c.v.p);
                else
                        (*IR->defconst)(p->type->op, p->type->size, p->u.c.v);
                p->u.c.loc = NULL;
        }
}
void checklab(Symbol p, void *cl) {
        if (!p->defined)
                error("undefined label `%s'\n", p->name);
        p->defined = 1;
}

Type enumdcl(void) {
        char *tag;
        Type ty;
        Symbol p;
        Coordinate pos;

        t = gettok();
        pos = src;
        if (t == ID) {
                tag = token;
                t = gettok();
        } else
                tag = "";
        if (t == '{') {
                static char follow[] = { IF, 0 };
                int n = 0;
                long k = -1;
                List idlist = 0;
                ty = newstruct(ENUM, tag);
                t = gettok();
                if (t != ID)
                        error("expecting an enumerator identifier\n");
                while (t == ID) {
                        char *id = token;
                        Coordinate s;
                        if (tsym && tsym->scope == level)
                                error("redeclaration of `%s' previously declared at %w\n",
                                        token, &tsym->src);
                        s = src;
                        t = gettok();
                        if (t == '=') {
                                t = gettok();
                                k = intexpr(0, 0);
                        } else {
                                if (k == inttype->u.sym->u.limits.max.i)
                                        error("overflow in value for enumeration constant `%s'\n", id);
                                k++;
                        }
                        p = install(id, &identifiers, level,  level < LOCAL ? PERM : FUNC);
                        p->src = s;
                        p->type = ty;
                        p->sclass = ENUM;
                        p->u.value = k;
                        idlist = append(p, idlist);
                        n++;
                        if (Aflag >= 2 && n == 128)
                                warning("more than 127 enumeration constants in `%t'\n", ty);
                        if (t != ',')
                                break;
                        t = gettok();
                        if (Aflag >= 2 && t == '}')
                                warning("non-ANSI trailing comma in enumerator list\n");
                }
                test('}', follow);
                ty->type = inttype;
                ty->size = ty->type->size;
                ty->align = ty->type->align;
                ty->u.sym->u.idlist = ltov(&idlist, PERM);
                ty->u.sym->defined = 1;
        } else if ((p = lookup(tag, types)) != NULL && p->type->op == ENUM) {
                ty = p->type;
                if (t == ';')
                        error("empty declaration\n");
        } else {
                error("unknown enumeration `%s'\n",  tag);
                ty = newstruct(ENUM, tag);
                ty->type = inttype;
        }
        if (*tag && xref)
                use(p, pos);
        return ty;
}

Type typename(void) {
        Type ty = specifier(NULL);

        if (t == '*' || t == '(' || t == '[') {
                ty = dclr(ty, NULL, NULL, 1);
                if (Aflag >= 1 && !hasproto(ty))
                        warning("missing prototype\n");
        }
        return ty;
}

