compiler: eliminate Decl.value_arena and Sema.perm_arena

The main motivation for this commit is eliminating Decl.value_arena.
Everything else is dominoes.

Decl.name used to be stored in the GPA, now it is stored in InternPool.
It ended up being simpler to migrate other strings to be interned as
well, such as struct field names, union field names, and a few others.
This ended up requiring a big diff, sorry about that. But the changes
are pretty nice, we finally start to take advantage of InternPool's
existence.

global_error_set and error_name_list are simplified. Now it is a single
ArrayHashMap(NullTerminatedString, void) and the index is the error tag
value.

Module.tmp_hack_arena is re-introduced (it was removed in
eeff407941560ce8eb5b737b2436dfa93cfd3a0c) in order to deal with
comptime_args, optimized_order, and struct and union fields. After
structs and unions get moved into InternPool properly, tmp_hack_arena
can be deleted again.

1 files changed, 8 insertions, 17 deletions

diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index 9d8076f592..b9b7772260 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -358,8 +358,9 @@ pub const DeclState = struct {
                             struct_obj.fields.keys(),
                             struct_obj.fields.values(),
                             0..,
-                        ) |field_name, field, field_index| {
+                        ) |field_name_ip, field, field_index| {
                             if (!field.ty.hasRuntimeBits(mod)) continue;
+                            const field_name = mod.intern_pool.stringToSlice(field_name_ip);
                             // DW.AT.member
                             try dbg_info_buffer.ensureUnusedCapacity(field_name.len + 2);
                             dbg_info_buffer.appendAssumeCapacity(@enumToInt(AbbrevKind.struct_member));
@@ -469,7 +470,8 @@ pub const DeclState = struct {
                     // DW.AT.member
                     try dbg_info_buffer.append(@enumToInt(AbbrevKind.struct_member));
                     // DW.AT.name, DW.FORM.string
-                    try dbg_info_buffer.writer().print("{s}\x00", .{field_name});
+                    try dbg_info_buffer.appendSlice(mod.intern_pool.stringToSlice(field_name));
+                    try dbg_info_buffer.append(0);
                     // DW.AT.type, DW.FORM.ref4
                     const index = dbg_info_buffer.items.len;
                     try dbg_info_buffer.resize(index + 4);
@@ -949,8 +951,7 @@ pub fn initDeclState(self: *Dwarf, mod: *Module, decl_index: Module.Decl.Index)
     defer tracy.end();
 
     const decl = mod.declPtr(decl_index);
-    const decl_name = try decl.getFullyQualifiedName(mod);
-    defer self.allocator.free(decl_name);
+    const decl_name = mod.intern_pool.stringToSlice(try decl.getFullyQualifiedName(mod));
 
     log.debug("initDeclState {s}{*}", .{ decl_name, decl });
 
@@ -1273,7 +1274,6 @@ pub fn commitDeclState(
         }
     }
 
-    log.debug("updateDeclDebugInfoAllocation for '{s}'", .{decl.name});
     try self.updateDeclDebugInfoAllocation(di_atom_index, @intCast(u32, dbg_info_buffer.items.len));
 
     while (decl_state.abbrev_relocs.popOrNull()) |reloc| {
@@ -1345,7 +1345,6 @@ pub fn commitDeclState(
         }
     }
 
-    log.debug("writeDeclDebugInfo for '{s}", .{decl.name});
     try self.writeDeclDebugInfo(di_atom_index, dbg_info_buffer.items);
 }
 
@@ -2523,15 +2522,7 @@ pub fn flushModule(self: *Dwarf, module: *Module) !void {
 
         // TODO: don't create a zig type for this, just make the dwarf info
         // without touching the zig type system.
-        const names = try arena.alloc(InternPool.NullTerminatedString, module.global_error_set.count());
-        {
-            var it = module.global_error_set.keyIterator();
-            var i: usize = 0;
-            while (it.next()) |key| : (i += 1) {
-                names[i] = module.intern_pool.getString(key.*).unwrap().?;
-            }
-        }
-
+        const names = try arena.dupe(InternPool.NullTerminatedString, module.global_error_set.keys());
         std.mem.sort(InternPool.NullTerminatedString, names, {}, InternPool.NullTerminatedString.indexLessThan);
 
         const error_ty = try module.intern(.{ .error_set_type = .{ .names = names } });
@@ -2682,8 +2673,8 @@ fn addDbgInfoErrorSet(
 
     const error_names = ty.errorSetNames(mod);
     for (error_names) |error_name_ip| {
+        const int = try mod.getErrorValue(error_name_ip);
         const error_name = mod.intern_pool.stringToSlice(error_name_ip);
-        const kv = mod.getErrorValue(error_name) catch unreachable;
         // DW.AT.enumerator
         try dbg_info_buffer.ensureUnusedCapacity(error_name.len + 2 + @sizeOf(u64));
         dbg_info_buffer.appendAssumeCapacity(@enumToInt(AbbrevKind.enum_variant));
@@ -2691,7 +2682,7 @@ fn addDbgInfoErrorSet(
         dbg_info_buffer.appendSliceAssumeCapacity(error_name);
         dbg_info_buffer.appendAssumeCapacity(0);
         // DW.AT.const_value, DW.FORM.data8
-        mem.writeInt(u64, dbg_info_buffer.addManyAsArrayAssumeCapacity(8), kv.value, target_endian);
+        mem.writeInt(u64, dbg_info_buffer.addManyAsArrayAssumeCapacity(8), int, target_endian);
     }
 
     // DW.AT.enumeration_type delimit children