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[qfcc] Handle l-value pointer dereferences again

Browse source 
While I still hate ".=", at least it's more hidden, and the new
implementation is a fair bit cleaner (hah, goto a label in an if (0) {}
block).

Most importantly, the expression tree code knows nothing about it. Now
just to figure out what broke func-epxr. A bit of whack-a-mole, but yay
for automated tests.
This commit is contained in:
Bill Currie 2020-03-13 22:14:30 +09:00
parent d150210888
commit 57134e01cd
1 changed files with 58 additions and 17 deletions
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63
tools/qfcc/source/statements.c
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@ -659,11 +659,11 @@ expr_assign_copy (sblock_t *sblock, expr_t *e, operand_t **op)
const char **opcode_set = opcode_sets[0];
const char *opcode;
int need_ptr = 0;
operand_t *dummy;
//operand_t *dummy;
if (src_expr->type == ex_expr && src_expr->e.expr.op == '=') {
sblock = statement_subexpr (sblock, src_expr, &dummy);
}
//if (src_expr->type == ex_expr && src_expr->e.expr.op == '=') {
// sblock = statement_subexpr (sblock, src_expr, &dummy);
//}
// follow the assignment chain to find the actual source expression
// (can't take the address of an assignment)
while (src_expr->type == ex_expr && src_expr->e.expr.op == '=') {
@ -726,21 +726,62 @@ expr_assign (sblock_t *sblock, expr_t *e, operand_t **op)
const char *opcode = convert_op (e->e.expr.op);
st_type_t type;
if (src_expr->type == ex_expr && src_expr->e.expr.op == '=') {
sblock = statement_subexpr (sblock, src_expr, &src);
if (is_structural (dst_type)) {
return expr_assign_copy (sblock, e, op);
}
if (is_indirect (dst_expr)) {
goto dereference_dst;
} else {
sblock = statement_subexpr (sblock, dst_expr, &dst);
}
} else {
if (is_structural (dst_type)) {
return expr_assign_copy (sblock, e, op);
}
if (e->e.expr.op == '=') {
if (is_indirect (dst_expr)) {
// If both dst_expr and src_expr are indirect, then a staging temp
// is needed, but emitting src_expr first generates that temp
// because src is null. If src_expr is not indirect and is a simple
// variable reference, then just the ref will be generated and thus
// will be assigned to the dereferenced destination. If src_expr
// is not simple, then a temp will be generated, so all good.
sblock = statement_subexpr (sblock, src_expr, &src);
goto dereference_dst;
} else {
// dst_expr is direct and known to be an l-value, so emitting
// its expression will simply generate a reference to that l-value
// which will be used as the default location to store src_expr's
// result
sblock = statement_subexpr (sblock, dst_expr, &dst);
src = dst;
sblock = statement_subexpr (sblock, src_expr, &src);
ofs = 0;
if (op)
*op = dst;
if (src == dst)
return sblock;
type = st_assign;
}
}
if (0) {
dereference_dst:
// dst_expr is a dereferenced pointer, so need to un-dereference it
// to get the pointer and switch to storep instructions.
dst_expr = address_expr (dst_expr, 0, 0);
opcode = ".="; // FIXME find a nicer representation (lose strings?)
if (dst_expr->type == ex_expr && !is_const_ptr (dst_expr->e.expr.e1)) {
sblock = statement_subexpr (sblock, dst_expr->e.expr.e1, &dst);
sblock = statement_subexpr (sblock, dst_expr->e.expr.e2, &ofs);
} else {
sblock = statement_subexpr (sblock, dst_expr, &dst);
ofs = 0;
}
}
if (op) {
*op = src;
}
if (src == dst) {
return sblock;
}
type = st_assign;
s = new_statement (type, opcode, e);
s->opa = src;
s->opb = dst;