quakeforge/tools/qfcc/source/expr_assign.c
Bill Currie 06d70a32db [qfcc] Rework the functionality of address expressions
The goal was to get lea being used for locals in ruamoko progs because
lea takes the base registers into account while the constant pointer
defs used by v6p cannot. Pointer defs are still used for gobals as they
may be out of reach of 16-bit addressing.

address_expr() has been simplified in that it no longer takes an offset:
the vast majority of the callers never passed one, and the few that did
have been reworked to use other mechanisms. In particular,
offset_pointer_expr does the manipulations needed to add an offset
(unscaled by type size) to a pointer. High-level pointer offsets still
apply a scale, though.

Alias expressions now do a better job of hanling aliasing of aliases by
simply replacing the target type when possible.
2022-01-25 23:39:17 +09:00

366 lines
9 KiB
C

/*
expr_assign.c
assignment expression construction and manipulations
Copyright (C) 2001 Bill Currie <bill@taniwha.org>
Author: Bill Currie <bill@taniwha.org>
Date: 2001/06/15
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif
#include <stdlib.h>
#include "QF/alloc.h"
#include "QF/dstring.h"
#include "QF/mathlib.h"
#include "QF/sys.h"
#include "QF/va.h"
#include "tools/qfcc/include/qfcc.h"
#include "tools/qfcc/include/class.h"
#include "tools/qfcc/include/def.h"
#include "tools/qfcc/include/defspace.h"
#include "tools/qfcc/include/diagnostic.h"
#include "tools/qfcc/include/emit.h"
#include "tools/qfcc/include/expr.h"
#include "tools/qfcc/include/function.h"
#include "tools/qfcc/include/idstuff.h"
#include "tools/qfcc/include/method.h"
#include "tools/qfcc/include/options.h"
#include "tools/qfcc/include/reloc.h"
#include "tools/qfcc/include/shared.h"
#include "tools/qfcc/include/strpool.h"
#include "tools/qfcc/include/struct.h"
#include "tools/qfcc/include/symtab.h"
#include "tools/qfcc/include/type.h"
#include "tools/qfcc/include/value.h"
static expr_t *
check_assign_logic_precedence (expr_t *dst, expr_t *src)
{
if (src->type == ex_expr && !src->paren && is_logic (src->e.expr.op)) {
// traditional QuakeC gives = higher precedence than && and ||
expr_t *assignment;
notice (src, "precedence of `=' and `%s' inverted for "
"traditional code", get_op_string (src->e.expr.op));
// change {a = (b logic c)} to {(a = b) logic c}
assignment = assign_expr (dst, src->e.expr.e1);
assignment->paren = 1; // protect assignment from binary_expr
return binary_expr (src->e.expr.op, assignment, src->e.expr.e2);
}
return 0;
}
int
is_lvalue (const expr_t *expr)
{
switch (expr->type) {
case ex_def:
return !expr->e.def->constant;
case ex_symbol:
switch (expr->e.symbol->sy_type) {
case sy_name:
break;
case sy_var:
return 1;
case sy_const:
break;
case sy_type:
break;
case sy_expr:
break;
case sy_func:
break;
case sy_class:
break;
case sy_convert:
break;
}
break;
case ex_temp:
return 1;
case ex_expr:
if (expr->e.expr.op == '.') {
return 1;
}
break;
case ex_alias:
return is_lvalue (expr->e.alias.expr);
case ex_address:
return 0;
case ex_assign:
return 0;
case ex_uexpr:
if (expr->e.expr.op == '.') {
return 1;
}
break;
case ex_branch:
case ex_memset:
case ex_compound:
case ex_state:
case ex_bool:
case ex_label:
case ex_labelref:
case ex_block:
case ex_vector:
case ex_nil:
case ex_value:
case ex_error:
case ex_selector:
case ex_return:
case ex_adjstk:
case ex_with:
case ex_args:
break;
case ex_count:
internal_error (expr, "invalid expression");
}
return 0;
}
static expr_t *
check_valid_lvalue (expr_t *expr)
{
if (!is_lvalue (expr)) {
if (options.traditional) {
warning (expr, "invalid lvalue in assignment");
return 0;
}
return error (expr, "invalid lvalue in assignment");
}
return 0;
}
static expr_t *
check_types_compatible (expr_t *dst, expr_t *src)
{
type_t *dst_type = get_type (dst);
type_t *src_type = get_type (src);
if (dst_type == src_type) {
return 0;
}
if (type_assignable (dst_type, src_type)) {
if (is_scalar (dst_type) && is_scalar (src_type)) {
if (!src->implicit) {
if (is_double (src_type)) {
warning (dst, "assignment of double to %s (use a cast)\n",
dst_type->name);
}
}
// the types are different but cast-compatible
expr_t *new = cast_expr (dst_type, src);
// the cast was a no-op, so the types are compatible at the
// low level (very true for default type <-> enum)
if (new != src) {
return assign_expr (dst, new);
}
}
return 0;
}
// traditional qcc is a little sloppy
if (!options.traditional) {
return type_mismatch (dst, src, '=');
}
if (is_func (dst_type) && is_func (src_type)) {
warning (dst, "assignment between disparate function types");
return 0;
}
if (is_float (dst_type) && is_vector (src_type)) {
warning (dst, "assignment of vector to float");
src = field_expr (src, new_name_expr ("x"));
return assign_expr (dst, src);
}
if (is_vector (dst_type) && is_float (src_type)) {
warning (dst, "assignment of float to vector");
dst = field_expr (dst, new_name_expr ("x"));
return assign_expr (dst, src);
}
return type_mismatch (dst, src, '=');
}
static expr_t *
assign_vector_expr (expr_t *dst, expr_t *src)
{
expr_t *dx, *sx;
expr_t *dy, *sy;
expr_t *dz, *sz;
expr_t *dw, *sw;
expr_t *ds, *ss;
expr_t *dv, *sv;
expr_t *block;
if (src->type == ex_vector) {
src = convert_vector (src);
if (src->type != ex_vector) {
// src was constant and thus converted
return assign_expr (dst, src);
}
}
if (src->type == ex_vector && dst->type != ex_vector) {
if (is_vector(src->e.vector.type)) {
// guaranteed to have three elements
sx = src->e.vector.list;
sy = sx->next;
sz = sy->next;
dx = field_expr (dst, new_name_expr ("x"));
dy = field_expr (dst, new_name_expr ("y"));
dz = field_expr (dst, new_name_expr ("z"));
block = new_block_expr ();
append_expr (block, assign_expr (dx, sx));
append_expr (block, assign_expr (dy, sy));
append_expr (block, assign_expr (dz, sz));
block->e.block.result = dst;
return block;
}
if (is_quaternion(src->e.vector.type)) {
// guaranteed to have two or four elements
if (src->e.vector.list->next->next) {
// four vals: x, y, z, w
sx = src->e.vector.list;
sy = sx->next;
sz = sy->next;
sw = sz->next;
dx = field_expr (dst, new_name_expr ("x"));
dy = field_expr (dst, new_name_expr ("y"));
dz = field_expr (dst, new_name_expr ("z"));
dw = field_expr (dst, new_name_expr ("w"));
block = new_block_expr ();
append_expr (block, assign_expr (dx, sx));
append_expr (block, assign_expr (dy, sy));
append_expr (block, assign_expr (dz, sz));
append_expr (block, assign_expr (dw, sw));
block->e.block.result = dst;
return block;
} else {
// v, s
sv = src->e.vector.list;
ss = sv->next;
dv = field_expr (dst, new_name_expr ("v"));
ds = field_expr (dst, new_name_expr ("s"));
block = new_block_expr ();
append_expr (block, assign_expr (dv, sv));
append_expr (block, assign_expr (ds, ss));
block->e.block.result = dst;
return block;
}
}
internal_error (src, "bogus vector expression");
}
return 0;
}
static __attribute__((pure)) int
is_memset (expr_t *e)
{
return e->type == ex_memset;
}
expr_t *
assign_expr (expr_t *dst, expr_t *src)
{
expr_t *expr;
type_t *dst_type, *src_type;
convert_name (dst);
if (dst->type == ex_error) {
return dst;
}
if ((expr = check_valid_lvalue (dst))) {
return expr;
}
dst_type = get_type (dst);
if (!dst_type) {
internal_error (dst, "dst_type broke in assign_expr");
}
if (src && !is_memset (src)) {
convert_name (src);
if (src->type == ex_error) {
return src;
}
if (options.traditional
&& (expr = check_assign_logic_precedence (dst, src))) {
return expr;
}
} else {
if (!src && is_scalar (dst_type)) {
return error (dst, "empty scalar initializer");
}
src = new_nil_expr ();
}
if (src->type == ex_compound) {
src = initialized_temp_expr (dst_type, src);
if (src->type == ex_error) {
return src;
}
}
src_type = get_type (src);
if (!src_type) {
internal_error (src, "src_type broke in assign_expr");
}
if (is_ptr (dst_type) && is_array (src_type)) {
// assigning an array to a pointer is the same as taking the address of
// the array but using the type of the array elements
src = address_expr (src, src_type->t.fldptr.type);
src_type = get_type (src);
}
if (src->type == ex_bool) {
// boolean expressions are chains of tests, so extract the result
// of the tests
src = convert_from_bool (src, dst_type);
if (src->type == ex_error) {
return src;
}
src_type = get_type (src);
}
if (!is_nil (src)) {
if ((expr = check_types_compatible (dst, src))) {
// expr might be a valid expression, but if so,
// check_types_compatible will take care of everything
return expr;
}
if ((expr = assign_vector_expr (dst, src))) {
return expr;
}
} else {
convert_nil (src, dst_type);
}
expr = new_assign_expr (dst, src);
return expr;
}