Show init.c syntax highlighted
#include "c.h"
static int curseg; /* current segment */
/* defpointer - initialize a pointer to p or to 0 if p==0 */
void defpointer(Symbol p) {
if (p) {
(*IR->defaddress)(p);
p->ref++;
} else {
static Value v;
(*IR->defconst)(P, voidptype->size, v);
}
}
/* genconst - generate/check constant expression e; return size */
static int genconst(Tree e, int def) {
for (;;)
switch (generic(e->op)) {
case ADDRG:
if (def)
(*IR->defaddress)(e->u.sym);
return e->type->size;
case CNST:
if (e->op == CNST+P && isarray(e->type)) {
e = cvtconst(e);
continue;
}
if (def)
(*IR->defconst)(e->type->op, e->type->size, e->u.v);
return e->type->size;
case RIGHT:
assert(e->kids[0] || e->kids[1]);
if (e->kids[1] && e->kids[0])
error("initializer must be constant\n");
e = e->kids[1] ? e->kids[1] : e->kids[0];
continue;
case CVP:
if (isarith(e->type))
error("cast from `%t' to `%t' is illegal in constant expressions\n",
e->kids[0]->type, e->type);
/* fall thru */
case CVI: case CVU: case CVF:
e = e->kids[0];
continue;
default:
error("initializer must be constant\n");
if (def)
genconst(consttree(0, inttype), def);
return inttype->size;
}
}
/* initvalue - evaluate a constant expression for a value of integer type ty */
static Tree initvalue(Type ty) {
Type aty;
Tree e;
needconst++;
e = expr1(0);
if ((aty = assign(ty, e)) != NULL)
e = cast(e, aty);
else {
error("invalid initialization type; found `%t' expected `%t'\n",
e->type, ty);
e = retype(consttree(0, inttype), ty);
}
needconst--;
if (generic(e->op) != CNST) {
error("initializer must be constant\n");
e = retype(consttree(0, inttype), ty);
}
return e;
}
/* initarray - initialize array of ty of <= len bytes; if len == 0, go to } */
static int initarray(int len, Type ty, int lev) {
int n = 0;
do {
initializer(ty, lev);
n += ty->size;
if (len > 0 && n >= len || t != ',')
break;
t = gettok();
} while (t != '}');
return n;
}
/* initchar - initialize array of <= len ty characters; if len == 0, go to } */
static int initchar(int len, Type ty) {
int n = 0;
char buf[16], *s = buf;
do {
*s++ = initvalue(ty)->u.v.i;
if (++n%inttype->size == 0) {
(*IR->defstring)(inttype->size, buf);
s = buf;
}
if (len > 0 && n >= len || t != ',')
break;
t = gettok();
} while (t != '}');
if (s > buf)
(*IR->defstring)(s - buf, buf);
return n;
}
/* initend - finish off an initialization at level lev; accepts trailing comma */
static void initend(int lev, char follow[]) {
if (lev == 0 && t == ',')
t = gettok();
test('}', follow);
}
/* initfields - initialize <= an unsigned's worth of bit fields in fields p to q */
static int initfields(Field p, Field q) {
unsigned int bits = 0;
int i, n = 0;
do {
i = initvalue(inttype)->u.v.i;
if (fieldsize(p) < 8*p->type->size) {
if (p->type == inttype &&
(i < -(int)(fieldmask(p)>>1)-1 || i > (int)(fieldmask(p)>>1))
|| p->type == unsignedtype && (i&~fieldmask(p)) != 0)
warning("initializer exceeds bit-field width\n");
i &= fieldmask(p);
}
bits |= i<<fieldright(p);
if (IR->little_endian) {
if (fieldsize(p) + fieldright(p) > n)
n = fieldsize(p) + fieldright(p);
} else {
if (fieldsize(p) + fieldleft(p) > n)
n = fieldsize(p) + fieldleft(p);
}
if (p->link == q)
break;
p = p->link;
} while (t == ',' && (t = gettok()) != 0);
n = (n + 7)/8;
for (i = 0; i < n; i++) {
Value v;
if (IR->little_endian) {
v.u = (unsigned char)bits;
bits >>= 8;
} else { /* a big endian */
v.u = (unsigned char)(bits>>(8*(unsignedtype->size - 1)));
bits <<= 8;
}
(*IR->defconst)(U, unsignedchar->size, v);
}
return n;
}
/* initstruct - initialize a struct ty of <= len bytes; if len == 0, go to } */
static int initstruct(int len, Type ty, int lev) {
int a, n = 0;
Field p = ty->u.sym->u.s.flist;
do {
if (p->offset > n) {
(*IR->space)(p->offset - n);
n += p->offset - n;
}
if (p->lsb) {
Field q = p;
while (q->link && q->link->offset == p->offset)
q = q->link;
n += initfields(p, q->link);
p = q;
} else {
initializer(p->type, lev);
n += p->type->size;
}
if (p->link) {
p = p->link;
a = p->type->align;
} else
a = ty->align;
if (a && n%a) {
(*IR->space)(a - n%a);
n = roundup(n, a);
}
if (len > 0 && n >= len || t != ',')
break;
t = gettok();
} while (t != '}');
return n;
}
/* initializer - constexpr | { constexpr ( , constexpr )* [ , ] } */
Type initializer(Type ty, int lev) {
int n = 0;
Tree e;
Type aty = NULL;
static char follow[] = { IF, CHAR, STATIC, 0 };
ty = unqual(ty);
if (isscalar(ty)) {
needconst++;
if (t == '{') {
t = gettok();
e = expr1(0);
initend(lev, follow);
} else
e = expr1(0);
e = pointer(e);
if ((aty = assign(ty, e)) != NULL)
e = cast(e, aty);
else
error("invalid initialization type; found `%t' expected `%t'\n",
e->type, ty);
n = genconst(e, 1);
deallocate(STMT);
needconst--;
}
if ((isunion(ty) || isstruct(ty)) && ty->size == 0) {
static char follow[] = { CHAR, STATIC, 0 };
error("cannot initialize undefined `%t'\n", ty);
skipto(';', follow);
return ty;
} else if (isunion(ty)) {
if (t == '{') {
t = gettok();
n = initstruct(ty->u.sym->u.s.flist->type->size, ty, lev + 1);
initend(lev, follow);
} else {
if (lev == 0)
error("missing { in initialization of `%t'\n", ty);
n = initstruct(ty->u.sym->u.s.flist->type->size, ty, lev + 1);
}
} else if (isstruct(ty)) {
if (t == '{') {
t = gettok();
n = initstruct(0, ty, lev + 1);
test('}', follow);
} else if (lev > 0)
n = initstruct(ty->size, ty, lev + 1);
else {
error("missing { in initialization of `%t'\n", ty);
n = initstruct(ty->u.sym->u.s.flist->type->size, ty, lev + 1);
}
}
if (isarray(ty))
aty = unqual(ty->type);
if (isarray(ty) && ischar(aty)) {
if (t == SCON) {
if (ty->size > 0 && ty->size == tsym->type->size - 1)
tsym->type = array(chartype, ty->size, 0);
n = tsym->type->size;
(*IR->defstring)(tsym->type->size, tsym->u.c.v.p);
t = gettok();
} else if (t == '{') {
t = gettok();
if (t == SCON) {
ty = initializer(ty, lev + 1);
initend(lev, follow);
return ty;
}
n = initchar(0, aty);
test('}', follow);
} else if (lev > 0 && ty->size > 0)
n = initchar(ty->size, aty);
else { /* eg, char c[] = 0; */
error("missing { in initialization of `%t'\n", ty);
n = initchar(1, aty);
}
} else if (isarray(ty)) {
if (t == SCON && aty == widechar) {
int i;
unsigned int *s = tsym->u.c.v.p;
if (ty->size > 0 && ty->size == tsym->type->size - widechar->size)
tsym->type = array(widechar, ty->size/widechar->size, 0);
n = tsym->type->size;
for (i = 0; i < n; i += widechar->size) {
Value v;
v.u = *s++;
(*IR->defconst)(widechar->op, widechar->size, v);
}
t = gettok();
} else if (t == '{') {
t = gettok();
if (t == SCON && aty == widechar) {
ty = initializer(ty, lev + 1);
initend(lev, follow);
return ty;
}
n = initarray(0, aty, lev + 1);
test('}', follow);
} else if (lev > 0 && ty->size > 0)
n = initarray(ty->size, aty, lev + 1);
else {
error("missing { in initialization of `%t'\n", ty);
n = initarray(aty->size, aty, lev + 1);
}
}
if (ty->size) {
if (n > ty->size)
error("too many initializers\n");
else if (n < ty->size)
(*IR->space)(ty->size - n);
} else if (isarray(ty) && ty->type->size > 0)
ty = array(ty->type, n/ty->type->size, 0);
else
ty->size = n;
return ty;
}
/* swtoseg - switch to segment seg, if necessary */
void swtoseg(int seg) {
if (curseg != seg)
(*IR->segment)(seg);
curseg = seg;
}
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