compiler: re-introduce dependencies for incremental compilation

Sema now tracks dependencies appropriately. Early logic in Zcu for
resolving outdated decls/functions is in place. The setup used does not
support `usingnamespace`; compilations using this construct are not yet
supported by this incremental compilation model.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/type.zig b/src/type.zig
index 9ca2822204..f53145a9d7 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -4,6 +4,7 @@ const Value = @import("value.zig").Value;
 const assert = std.debug.assert;
 const Target = std.Target;
 const Module = @import("Module.zig");
+const Zcu = Module;
 const log = std.log.scoped(.Type);
 const target_util = @import("target.zig");
 const TypedValue = @import("TypedValue.zig");
@@ -3228,6 +3229,17 @@ pub const Type = struct {
         };
     }
 
+    pub fn typeDeclInst(ty: Type, zcu: *const Zcu) ?InternPool.TrackedInst.Index {
+        return switch (zcu.intern_pool.indexToKey(ty.toIntern())) {
+            inline .struct_type,
+            .union_type,
+            .enum_type,
+            .opaque_type,
+            => |info| info.zir_index.unwrap(),
+            else => null,
+        };
+    }
+
     pub const @"u1": Type = .{ .ip_index = .u1_type };
     pub const @"u8": Type = .{ .ip_index = .u8_type };
     pub const @"u16": Type = .{ .ip_index = .u16_type };