use a declarative table for CLI linker argument parsing #14663
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This issue is limited in scope and/or knowledge of Zig internals.
enhancement
Solving this issue will likely involve adding new logic or components to the codebase.
zig cc
Zig as a drop-in C compiler feature
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andrewrk
added
enhancement
|
semi-related to #11801 as that requires to reorder + check linker flags. |
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@andrewrk would something like this be an acceptable solution? pub fn LinkerArgumentTable(comptime table: anytype) type {
return struct {
const Table = @TypeOf(table);
const Tag = std.meta.FieldEnum(Table);
pub fn get(argument: []const u8) ?Tag {
const fields = std.meta.fields(Table);
inline for (fields, 0..) |field, field_index| {
const array = @field(table, field.name);
inline for (array) |each| {
if (std.mem.eql(u8, each, argument)) return @intToEnum(Tag, field_index);
}
}
return null;
}
pub fn getPartial(argument: []const u8) ?Tag {
const fields = std.meta.fields(Table);
inline for (fields, 0..) |field, field_index| {
const array = @field(table, field.name);
inline for (array) |each| {
if (std.mem.startsWith(u8, each, argument)) return @intToEnum(Tag, field_index);
}
}
return null;
}
};
}
const wl_table = .{
.as_needed = .{"--as-needed"},
.no_as_needed = .{"--no-as-needed"},
.want_pie = .{"-no-pie"},
.sort_common = .{"--sort-common"},
.whole_archive = .{ "-whole-arcive", "--whole-archive" },
};
test "wl_linker_map" {
const Table = LinkerArgumentTable(wl_table);
const current_argument = "--whole-archive";
const result = Table.get(current_argument);
try std.testing.expect(result != null);
try std.testing.expect(result.? == .whole_archive);
}
It would then use one table for the wl options, and two tables for the main argument list, one for all except matches and a smaller one for all the partials one where you have some kind of key+value. |
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In Zig's CLI, linker arguments are parsed here:
zig/src/main.zig
Lines 1788 to 2222 in 705e9cb
The problem is that it's not a complete list, and some aliased forms are not supported. A declarative table of linker arguments would be easier to compare against other linker implementations. The table could also be initially seeded by examining the output of LLD's Options.td files, for example.
Note that some linker arguments are special-cased and handled inline with other arguments, like this:
zig/src/main.zig
Lines 1606 to 1668 in 705e9cb
It is important to keep this logic how it is, but it could integrate with a declarative linker arg parsing system if it were flexible enough.
I think the key here is going to be not making the API too abstract. Something akin to a "linker argument iterator" might work nicely.
This will improve the robustness of zig cc as a drop-in linker.
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