Commit a8bd55e0853f7f80c9cd843ec54813425e4276bc | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2023-03-07 22:24:50+00:00
committer	Veikka Tuominen <git@vexu.eu> 2023-03-12 19:07:06+02:00
log	a8bd55e0853f7f80c9cd843ec54813425e4276bc
tree	43c45d380722b2f9b32a650d0b4e30a8d1788ff3
parent	c93e0d86187cb589d6726acd36f741f3d87a96be

translate-c: translate extern unknown-length arrays using @extern

Resolves: #14743

3 files changed, 51 insertions(+), 1 deletions(-)

src
- translate_c.zig
- translate_c
  - ast.zig
test
- translate_c.zig

src/translate_c.zig+15-1

...	...	@@ -784,9 +784,9 @@ fn visitVarDecl(c: Context, var_decl: const clang.VarDecl, mangled_name: ?[]co
784	784
785	785	const qual_type = var_decl.getTypeSourceInfo_getType();
786	786	const storage_class = var_decl.getStorageClass();
787		const is_const = qual_type.isConstQualified();
788	787	const has_init = var_decl.hasInit();
789	788	const decl_init = var_decl.getInit();
	789	var is_const = qual_type.isConstQualified();
790	790
791	791	// In C extern variables with initializers behave like Zig exports.
792	792	// extern int foo = 2;
...	...	@@ -843,6 +843,20 @@ fn visitVarDecl(c: Context, var_decl: const clang.VarDecl, mangled_name: ?[]co
843	843
844	844	// std.mem.zeroes(T)
845	845	init_node = try Tag.std_mem_zeroes.create(c.arena, type_node);
	846	} else if (qual_type.getTypeClass() == .IncompleteArray) {
	847	// Oh no, an extern array of unknown size! These are really fun because there's no
	848	// direct equivalent in Zig. To translate correctly, we'll have to create a C-pointer
	849	// to the data initialized via @extern.
	850
	851	const name_str = try std.fmt.allocPrint(c.arena, "\"{s}\"", .{var_name});
	852	init_node = try Tag.builtin_extern.create(c.arena, .{
	853	.type = type_node,
	854	.name = try Tag.string_literal.create(c.arena, name_str),
	855	});
	856
	857	// Since this is really a pointer to the underlying data, we tweak a few properties.
	858	is_extern = false;
	859	is_const = true;
846	860	}
847	861
848	862	const linksection_string = blk: {

src/translate_c/ast.zig+28

...	...	@@ -158,6 +158,8 @@ pub const Node = extern union {
158	158	vector_zero_init,
159	159	/// @shuffle(type, a, b, mask)
160	160	shuffle,
	161	/// @extern(ty, .{ .name = n })
	162	builtin_extern,
161	163
162	164	/// @import("std").zig.c_translation.MacroArithmetic.<op>(lhs, rhs)
163	165	macro_arithmetic,
...	...	@@ -373,6 +375,7 @@ pub const Node = extern union {
373	375	.field_access => Payload.FieldAccess,
374	376	.string_slice => Payload.StringSlice,
375	377	.shuffle => Payload.Shuffle,
	378	.builtin_extern => Payload.Extern,
376	379	.macro_arithmetic => Payload.MacroArithmetic,
377	380	};
378	381	}
...	...	@@ -718,6 +721,14 @@ pub const Payload = struct {
718	721	},
719	722	};
720	723
	724	pub const Extern = struct {
	725	base: Payload,
	726	data: struct {
	727	type: Node,
	728	name: Node,
	729	},
	730	};
	731
721	732	pub const MacroArithmetic = struct {
722	733	base: Payload,
723	734	data: struct {
...	...	@@ -1409,6 +1420,22 @@ fn renderNode(c: *Context, node: Node) Allocator.Error!NodeIndex {
1409	1420	payload.mask_vector,
1410	1421	});
1411	1422	},
	1423	.builtin_extern => {
	1424	const payload = node.castTag(.builtin_extern).?.data;
	1425
	1426	var info_inits: [1]Payload.ContainerInitDot.Initializer = .{
	1427	.{ .name = "name", .value = payload.name },
	1428	};
	1429	var info_payload: Payload.ContainerInitDot = .{
	1430	.base = .{ .tag = .container_init_dot },
	1431	.data = &info_inits,
	1432	};
	1433
	1434	return renderBuiltinCall(c, "@extern", &.{
	1435	payload.type,
	1436	.{ .ptr_otherwise = &info_payload.base },
	1437	});
	1438	},
1412	1439	.macro_arithmetic => {
1413	1440	const payload = node.castTag(.macro_arithmetic).?.data;
1414	1441	const op = @tagName(payload.op);
...	...	@@ -2348,6 +2375,7 @@ fn renderNodeGrouped(c: *Context, node: Node) !NodeIndex {
2348	2375	.div_exact,
2349	2376	.offset_of,
2350	2377	.shuffle,
	2378	.builtin_extern,
2351	2379	.static_local_var,
2352	2380	.mut_str,
2353	2381	.macro_arithmetic,

test/translate_c.zig+8

...	...	@@ -3948,4 +3948,12 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
3948	3948	\\}
3949	3949	});
3950	3950	}
	3951
	3952	cases.add("extern array of unknown length",
	3953	\\extern int foo[];
	3954	, &[_][]const u8{
	3955	\\const foo: [c]c_int = @extern([c]c_int, .{
	3956	\\ .name = "foo",
	3957	\\});
	3958	});
3951	3959	}