InternPool: rename `Depender` to `AnalSubject`

This is essentially just a rename. I also changed the representation of
`AnalSubject` to use a `packed struct` rather than a non-exhaustive
enum, but that change is relatively trivial.

1 files changed, 25 insertions, 25 deletions

diff --git a/src/InternPool.zig b/src/InternPool.zig
index 4268a84f37..cf56550c25 100644
--- a/src/InternPool.zig
+++ b/src/InternPool.zig
@@ -81,7 +81,7 @@ namespace_name_deps: std.AutoArrayHashMapUnmanaged(NamespaceNameKey, DepEntry.In
 /// Given a `Depender`, points to an entry in `dep_entries` whose `depender`
 /// matches. The `next_dependee` field can be used to iterate all such entries
 /// and remove them from the corresponding lists.
-first_dependency: std.AutoArrayHashMapUnmanaged(Depender, DepEntry.Index) = .{},
+first_dependency: std.AutoArrayHashMapUnmanaged(AnalSubject, DepEntry.Index) = .{},
 
 /// Stores dependency information. The hashmaps declared above are used to look
 /// up entries in this list as required. This is not stored in `extra` so that
@@ -132,39 +132,39 @@ pub fn trackZir(ip: *InternPool, gpa: Allocator, file: *Module.File, inst: Zir.I
     return @enumFromInt(gop.index);
 }
 
-/// Reperesents the "source" of a dependency edge, i.e. either a Decl or a
-/// runtime function (represented as an InternPool index).
-/// MSB is 0 for a Decl, 1 for a function.
-pub const Depender = enum(u32) {
-    _,
+/// Analysis Subject. Represents a single entity which undergoes semantic analysis.
+/// This is either a `Decl` (in future `Cau`) or a runtime function.
+/// The LSB is used as a tag bit.
+/// This is the "source" of an incremental dependency edge.
+pub const AnalSubject = packed struct(u32) {
+    kind: enum(u1) { decl, func },
+    index: u31,
     pub const Unwrapped = union(enum) {
         decl: DeclIndex,
         func: InternPool.Index,
     };
-    pub fn unwrap(dep: Depender) Unwrapped {
-        const tag: u1 = @truncate(@intFromEnum(dep) >> 31);
-        const val: u31 = @truncate(@intFromEnum(dep));
-        return switch (tag) {
-            0 => .{ .decl = @enumFromInt(val) },
-            1 => .{ .func = @enumFromInt(val) },
+    pub fn unwrap(as: AnalSubject) Unwrapped {
+        return switch (as.kind) {
+            .decl => .{ .decl = @enumFromInt(as.index) },
+            .func => .{ .func = @enumFromInt(as.index) },
         };
     }
-    pub fn wrap(raw: Unwrapped) Depender {
-        return @enumFromInt(switch (raw) {
-            .decl => |decl| @intFromEnum(decl),
-            .func => |func| (1 << 31) | @intFromEnum(func),
-        });
+    pub fn wrap(raw: Unwrapped) AnalSubject {
+        return switch (raw) {
+            .decl => |decl| .{ .kind = .decl, .index = @intCast(@intFromEnum(decl)) },
+            .func => |func| .{ .kind = .func, .index = @intCast(@intFromEnum(func)) },
+        };
     }
-    pub fn toOptional(dep: Depender) Optional {
-        return @enumFromInt(@intFromEnum(dep));
+    pub fn toOptional(as: AnalSubject) Optional {
+        return @enumFromInt(@as(u32, @bitCast(as)));
     }
     pub const Optional = enum(u32) {
         none = std.math.maxInt(u32),
         _,
-        pub fn unwrap(opt: Optional) ?Depender {
+        pub fn unwrap(opt: Optional) ?AnalSubject {
             return switch (opt) {
                 .none => null,
-                _ => @enumFromInt(@intFromEnum(opt)),
+                _ => @bitCast(@intFromEnum(opt)),
             };
         }
     };
@@ -178,7 +178,7 @@ pub const Dependee = union(enum) {
     namespace_name: NamespaceNameKey,
 };
 
-pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender: Depender) void {
+pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender: AnalSubject) void {
     var opt_idx = (ip.first_dependency.fetchSwapRemove(depender) orelse return).value.toOptional();
 
     while (opt_idx.unwrap()) |idx| {
@@ -207,7 +207,7 @@ pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender:
 pub const DependencyIterator = struct {
     ip: *const InternPool,
     next_entry: DepEntry.Index.Optional,
-    pub fn next(it: *DependencyIterator) ?Depender {
+    pub fn next(it: *DependencyIterator) ?AnalSubject {
         const idx = it.next_entry.unwrap() orelse return null;
         const entry = it.ip.dep_entries.items[@intFromEnum(idx)];
         it.next_entry = entry.next;
@@ -236,7 +236,7 @@ pub fn dependencyIterator(ip: *const InternPool, dependee: Dependee) DependencyI
     };
 }
 
-pub fn addDependency(ip: *InternPool, gpa: Allocator, depender: Depender, dependee: Dependee) Allocator.Error!void {
+pub fn addDependency(ip: *InternPool, gpa: Allocator, depender: AnalSubject, dependee: Dependee) Allocator.Error!void {
     const first_depender_dep: DepEntry.Index.Optional = if (ip.first_dependency.get(depender)) |idx| dep: {
         // The entry already exists, so there is capacity to overwrite it later.
         break :dep idx.toOptional();
@@ -300,7 +300,7 @@ pub const DepEntry = extern struct {
     /// the first and only entry in one of `intern_pool.*_deps`, and does not
     /// appear in any list by `first_dependency`, but is not in
     /// `free_dep_entries` since `*_deps` stores a reference to it.
-    depender: Depender.Optional,
+    depender: AnalSubject.Optional,
     /// Index into `dep_entries` forming a doubly linked list of all dependencies on this dependee.
     /// Used to iterate all dependers for a given dependee during an update.
     /// null if this is the end of the list.