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Introduce array pointer decay.

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This commit is contained in:
Christoffer Lerno
2021-12-09 00:49:50 +01:00
parent b003b05d5d
commit 4bc47a195b
3 changed files with 131 additions and 1 deletions
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47
src/compiler/sema_expr.c
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@@ -24,6 +24,21 @@ static inline void expr_set_as_const_list(Expr *expr, ConstInitializer *list)
expr->const_expr.list = list;
}
static bool sema_decay_array_pointers(Expr *expr)
{
Type *expr_type = expr->type->canonical;
if (expr_type->type_kind != TYPE_POINTER) return true;
switch (expr_type->pointer->type_kind)
{
case TYPE_ARRAY:
return cast_implicit(expr, type_get_ptr(expr_type->pointer->array.base));
case TYPE_VECTOR:
return cast_implicit(expr, type_get_ptr(expr_type->pointer->vector.base));
default:
return true;
}
}
int BINOP_PREC_REQ[BINARYOP_LAST + 1] =
{
// bitwise operations
@@ -2245,6 +2260,22 @@ static inline bool sema_expr_analyse_call(Context *context, Expr *expr)
return sema_expr_analyse_general_call(context, expr, decl, struct_var, macro, failable);
}
static void sema_deref_array_pointers(Expr *expr)
{
Type *expr_type = expr->type->canonical;
if (expr_type->type_kind == TYPE_POINTER)
{
switch (expr_type->pointer->type_kind)
{
case TYPE_ARRAY:
case TYPE_VECTOR:
expr_insert_deref(expr);
break;
default:
break;
}
}
}
static bool expr_check_index_in_range(Context *context, Type *type, Expr *index_expr, bool end_index, bool from_end)
{
@@ -2342,6 +2373,7 @@ static inline bool sema_expr_analyse_subscript(Context *context, Expr *expr, boo
// 1. Evaluate the expression to index.
Expr *subscripted = expr->subscript_expr.expr;
if (!sema_analyse_expr_lvalue(context, subscripted)) return false;
sema_deref_array_pointers(subscripted);
// 2. Evaluate the index.
Expr *index = expr->subscript_expr.index;
@@ -2351,6 +2383,7 @@ static inline bool sema_expr_analyse_subscript(Context *context, Expr *expr, boo
bool failable = IS_FAILABLE(subscripted);
Type *underlying_type = type_flatten(subscripted->type);
Type *current_type = underlying_type;
Expr *current_expr = subscripted;
@@ -4314,6 +4347,9 @@ static bool sema_expr_analyse_add_sub_assign(Context *context, Expr *expr, Expr
if (left_type_canonical->type_kind == TYPE_POINTER)
{
if (!sema_decay_array_pointers(left)) return false;
expr->type = left->type;
// 7. Finally, check that the right side is indeed an integer.
if (!type_is_integer(right->type->canonical))
{
@@ -4430,9 +4466,15 @@ static bool sema_expr_analyse_sub(Context *context, Expr *expr, Expr *left, Expr
// 2. Handle the ptr - x and ptr - other_pointer
if (left_type->type_kind == TYPE_POINTER)
{
if (!sema_decay_array_pointers(left)) return false;
left_type = type_no_fail(left->type)->canonical;
// 3. ptr - other pointer
if (right_type->type_kind == TYPE_POINTER)
{
if (!sema_decay_array_pointers(right)) return false;
right_type = type_no_fail(right->type)->canonical;
// 3a. Require that both types are the same.
unify_voidptr(left, right, &left_type, &right_type);
if (left_type != right_type)
@@ -4544,6 +4586,8 @@ static bool sema_expr_analyse_add(Context *context, Expr *expr, Expr *left, Expr
// so check if we want to do the normal pointer add special handling.
if (left_type->type_kind == TYPE_POINTER)
{
if (!sema_decay_array_pointers(left)) return false;
// 3a. Check that the other side is an integer of some sort.
if (!type_is_integer(right_type))
{
@@ -5045,6 +5089,7 @@ static bool sema_expr_analyse_comp(Context *context, Expr *expr, Expr *left, Exp
}
if (type_flatten(max)->type_kind == TYPE_POINTER)
{
// Only comparisons between the same type is allowed. Subtypes not allowed.
if (left_type != right_type && left_type != type_voidptr && right_type != type_voidptr)
{
@@ -5475,6 +5520,8 @@ static inline bool sema_expr_analyse_incdec(Context *context, Expr *expr)
return false;
}
if (!sema_decay_array_pointers(inner)) return false;
// 6. Done, the result is same as the inner type.
expr->type = inner->type;
return true;

2
src/version.h
View File

@@ -1 +1 @@
#define COMPILER_VERSION "PRE.4"
#define COMPILER_VERSION "PRE.5"

83
test/test_suite/pointers/array_pointer_decay.c3t Normal file
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@@ -0,0 +1,83 @@
// #target: x64-darwin
module foo;
extern fn void printf(char*, ...);
fn void main()
{
int[3] x;
int[3]* y = &x;
int* z = y;
int[] sub = y;
int y1 = y[1];
int z1 = z[1];
int* xx = &x + 1;
int[3]* yy = (int[3]*)(xx);
int* zz = yy - 1;
printf("%p = %p = %p, %p = %p\n", y, z, zz, &y[1], xx);
x[1] = 123;
printf("%d = %d\n", (&x)[1], y[1]);
}
/* #expect: foo.ll
define void @main() #0 {
entry:
%x = alloca [3 x i32], align 4
%y = alloca [3 x i32]*, align 8
%z = alloca i32*, align 8
%sub = alloca %"int[]", align 8
%y1 = alloca i32, align 4
%z1 = alloca i32, align 4
%xx = alloca i32*, align 8
%yy = alloca [3 x i32]*, align 8
%zz = alloca i32*, align 8
%0 = getelementptr inbounds [3 x i32], [3 x i32]* %x, i64 0, i64 0
store i32 0, i32* %0, align 4
%1 = getelementptr inbounds [3 x i32], [3 x i32]* %x, i64 0, i64 1
store i32 0, i32* %1, align 4
%2 = getelementptr inbounds [3 x i32], [3 x i32]* %x, i64 0, i64 2
store i32 0, i32* %2, align 4
store [3 x i32]* %x, [3 x i32]** %y, align 8
%3 = load [3 x i32]*, [3 x i32]** %y, align 8
%ptrptr = bitcast [3 x i32]* %3 to i32*
store i32* %ptrptr, i32** %z, align 8
%4 = load [3 x i32]*, [3 x i32]** %y, align 8
%5 = bitcast [3 x i32]* %4 to i32*
%6 = insertvalue %"int[]" undef, i32* %5, 0
%7 = insertvalue %"int[]" %6, i64 3, 1
store %"int[]" %7, %"int[]"* %sub, align 8
%8 = load [3 x i32]*, [3 x i32]** %y, align 8
%9 = getelementptr inbounds [3 x i32], [3 x i32]* %8, i64 0, i64 1
%10 = load i32, i32* %9, align 4
store i32 %10, i32* %y1, align 4
%11 = load i32*, i32** %z, align 8
%ptroffset = getelementptr inbounds i32, i32* %11, i64 1
%12 = load i32, i32* %ptroffset, align 4
store i32 %12, i32* %z1, align 4
%ptrptr1 = bitcast [3 x i32]* %x to i32*
%ptroffset2 = getelementptr i32, i32* %ptrptr1, i64 1
store i32* %ptroffset2, i32** %xx, align 8
%13 = load i32*, i32** %xx, align 8
%ptrptr3 = bitcast i32* %13 to [3 x i32]*
store [3 x i32]* %ptrptr3, [3 x i32]** %yy, align 8
%14 = load [3 x i32]*, [3 x i32]** %yy, align 8
%ptrptr4 = bitcast [3 x i32]* %14 to i32*
%ptroffset5 = getelementptr i32, i32* %ptrptr4, i64 -1
store i32* %ptroffset5, i32** %zz, align 8
%15 = load [3 x i32]*, [3 x i32]** %y, align 8
%16 = load i32*, i32** %z, align 8
%17 = load i32*, i32** %zz, align 8
%18 = load [3 x i32]*, [3 x i32]** %y, align 8
%19 = getelementptr inbounds [3 x i32], [3 x i32]* %18, i64 0, i64 1
%20 = load i32*, i32** %xx, align 8
call void (i8*, ...) @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i32 0, i32 0), [3 x i32]* %15, i32* %16, i32* %17, i32* %19, i32* %20)
%21 = getelementptr inbounds [3 x i32], [3 x i32]* %x, i64 0, i64 1
store i32 123, i32* %21, align 4
%22 = getelementptr inbounds [3 x i32], [3 x i32]* %x, i64 0, i64 1
%23 = load i32, i32* %22, align 4
%24 = load [3 x i32]*, [3 x i32]** %y, align 8
%25 = getelementptr inbounds [3 x i32], [3 x i32]* %24, i64 0, i64 1
%26 = load i32, i32* %25, align 4
call void (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.1, i32 0, i32 0), i32 %23, i32 %26)
ret void
}