Commit c0c9d11d8c509fdd1e60492abb1215d9860c3d39 | zig

author	Michael Dusan <michael.dusan@gmail.com> 2020-06-05 00:48:36-04:00
committer	Michael Dusan <michael.dusan@gmail.com> 2020-06-05 00:49:57-04:00
log	c0c9d11d8c509fdd1e60492abb1215d9860c3d39
tree	0fa83a1731000ea6d0c760817ccc5434652d713c
parent	f839d34baa8213048a1f073a38bf9b54af74711d
signature	Commit is signed but in an unrecognized format.

stage1: fix constness in some corner cases

- for one-possible-value types, ir_analyze_struct_field_ptr()
  no longer hardcodes const/volatile

- when slicing arrays, ir_analyze_instruction_slice()
  no longer consults ConstValSpecialStatic

closes #5474

3 files changed, 62 insertions(+), 4 deletions(-)

src
- ir.cpp
test
- stage1
  - behavior.zig
  - behavior
    bugs
    5474.zig

src/ir.cpp+4-4

 @@ -21924,7 +21924,9 @@ static IrInstGen *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInst* source_ins
         case OnePossibleValueYes: {
             IrInstGen *elem = ir_const_move(ira, source_instr,
                  get_the_one_possible_value(ira->codegen, field_type));
-            return ir_get_ref(ira, source_instr, elem, false, false);
+            return ir_get_ref(ira, source_instr, elem,
+                struct_ptr->value->type->data.pointer.is_const,
+                struct_ptr->value->type->data.pointer.is_volatile);
         }
         case OnePossibleValueNo:
             break;
 @@ -27097,10 +27099,8 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
     if (array_type->id == ZigTypeIdArray) {
         elem_type = array_type->data.array.child_type;
-        bool is_comptime_const = ptr_ptr->value->special == ConstValSpecialStatic &&
-            ptr_ptr->value->data.x_ptr.mut == ConstPtrMutComptimeConst;
         non_sentinel_slice_ptr_type = get_pointer_to_type_extra(ira->codegen, elem_type,
-            ptr_ptr_type->data.pointer.is_const || is_comptime_const,
+            ptr_ptr_type->data.pointer.is_const,
             ptr_ptr_type->data.pointer.is_volatile,
             PtrLenUnknown,
             ptr_ptr_type->data.pointer.explicit_alignment, 0, 0, false);

test/stage1/behavior.zig+1

...	@@ -50,6 +50,7 @@ comptime {	...	@@ -50,6 +50,7 @@ comptime {
50	_ = @import("behavior/bugs/4769_b.zig");	50	_ = @import("behavior/bugs/4769_b.zig");
51	_ = @import("behavior/bugs/4769_c.zig");	51	_ = @import("behavior/bugs/4769_c.zig");
52	_ = @import("behavior/bugs/4954.zig");	52	_ = @import("behavior/bugs/4954.zig");
		53	_ = @import("behavior/bugs/5474.zig");
53	_ = @import("behavior/bugs/5487.zig");	54	_ = @import("behavior/bugs/5487.zig");
54	_ = @import("behavior/bugs/394.zig");	55	_ = @import("behavior/bugs/394.zig");
55	_ = @import("behavior/bugs/421.zig");	56	_ = @import("behavior/bugs/421.zig");

test/stage1/behavior/bugs/5474.zig created+57

...	@@ -0,0 +1,57 @@
1	const std = @import("std");
2
3	// baseline (control) struct with array of scalar
4	const Box0 = struct {
5	items: [4]Item,
6
7	const Item = struct {
8	num: u32,
9	};
10	};
11
12	// struct with array of empty struct
13	const Box1 = struct {
14	items: [4]Item,
15
16	const Item = struct {};
17	};
18
19	// struct with array of zero-size struct
20	const Box2 = struct {
21	items: [4]Item,
22
23	const Item = struct {
24	nothing: void,
25	};
26	};
27
28	fn doTest() void {
29	// var
30	{
31	var box0: Box0 = .{ .items = undefined };
32	std.testing.expect(@typeInfo(@TypeOf(box0.items[0..])).Pointer.is_const == false);
33
34	var box1: Box1 = .{ .items = undefined };
35	std.testing.expect(@typeInfo(@TypeOf(box1.items[0..])).Pointer.is_const == false);
36
37	var box2: Box2 = .{ .items = undefined };
38	std.testing.expect(@typeInfo(@TypeOf(box2.items[0..])).Pointer.is_const == false);
39	}
40
41	// const
42	{
43	const box0: Box0 = .{ .items = undefined };
44	std.testing.expect(@typeInfo(@TypeOf(box0.items[0..])).Pointer.is_const == true);
45
46	const box1: Box1 = .{ .items = undefined };
47	std.testing.expect(@typeInfo(@TypeOf(box1.items[0..])).Pointer.is_const == true);
48
49	const box2: Box2 = .{ .items = undefined };
50	std.testing.expect(@typeInfo(@TypeOf(box2.items[0..])).Pointer.is_const == true);
51	}
52	}
53
54	test "pointer-to-array constness for zero-size elements" {
55	doTest();
56	comptime doTest();
57	}