zig

commit cea310c9082a985b103953dd84579aa1a6dce6ea (tree)
parent 18f30346291bd2471e07924af161de080935dd60
Author: Jimmi Holst Christensen <jhc@dismail.de>
Date:   Mon, 25 Apr 2022 19:08:39 +0200

Remove usage of inline for from print_targets.cmdTargets

This function was one of the biggest zig functions in a debug build of
the compiler.

  $ bloaty stage3-debug/bin/zig -d symbols --tsv -n 10000000 |
      rg -v '(llvm|clang|std|lld|\(anonymous namespace\))::|\[section ' |
      sort -h -k 3

  ...
  translate_c.ast.renderNode                    86168   86219
  main.buildOutputType                         177959  178004
  InfoTable                                    184832  184870
  AArch64SVEIntrinsicMap                       188544  188596
  print_targets.cmdTargets__anon_4735          319156  319216
  __static_initialization_and_destruction_0()  486666  489582
  MatchTable1                                  621884  621997
  OperandMatchTable                           1139622 1139861
  MatchTable0                                 1899764 1900141

Diffstat:
M
lib/std/meta.zig
 | 
27
+++++++++++++++++++++++++++
M
src/print_targets.zig
 | 
27
++++++++++++---------------

2 files changed, 39 insertions(+), 15 deletions(-)
diff --git a/lib/std/meta.zig b/lib/std/meta.zig
@@ -568,6 +568,33 @@ test "std.meta.fieldNames" {
     try testing.expectEqualSlices(u8, u1names[1], "b");
 }
 
+/// Given an enum or error set type, returns a pointer to an array containing all tags for that
+/// enum or error set.
+pub fn tags(comptime T: type) *const [fields(T).len]T {
+    comptime {
+        const fieldInfos = fields(T);
+        var res: [fieldInfos.len]T = undefined;
+        for (fieldInfos) |field, i| {
+            res[i] = @field(T, field.name);
+        }
+        return &res;
+    }
+}
+
+test "std.meta.tags" {
+    const E1 = enum { A, B };
+    const E2 = error{A};
+
+    const e1_tags = tags(E1);
+    const e2_tags = tags(E2);
+
+    try testing.expect(e1_tags.len == 2);
+    try testing.expectEqual(E1.A, e1_tags[0]);
+    try testing.expectEqual(E1.B, e1_tags[1]);
+    try testing.expect(e2_tags.len == 1);
+    try testing.expectEqual(E2.A, e2_tags[0]);
+}
+
 pub fn FieldEnum(comptime T: type) type {
     const field_infos = fields(T);
     var enumFields: [field_infos.len]std.builtin.Type.EnumField = undefined;
diff --git a/src/print_targets.zig b/src/print_targets.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const fs = std.fs;
 const io = std.io;
 const mem = std.mem;
+const meta = std.meta;
 const Allocator = mem.Allocator;
 const Target = std.Target;
 const target = @import("target.zig");
@@ -35,27 +36,25 @@ pub fn cmdTargets(
 
     try jws.objectField("arch");
     try jws.beginArray();
-    {
-        inline for (@typeInfo(Target.Cpu.Arch).Enum.fields) |field| {
-            try jws.arrayElem();
-            try jws.emitString(field.name);
-        }
+    for (meta.fieldNames(Target.Cpu.Arch)) |field| {
+        try jws.arrayElem();
+        try jws.emitString(field);
     }
     try jws.endArray();
 
     try jws.objectField("os");
     try jws.beginArray();
-    inline for (@typeInfo(Target.Os.Tag).Enum.fields) |field| {
+    for (meta.fieldNames(Target.Os.Tag)) |field| {
         try jws.arrayElem();
-        try jws.emitString(field.name);
+        try jws.emitString(field);
     }
     try jws.endArray();
 
     try jws.objectField("abi");
     try jws.beginArray();
-    inline for (@typeInfo(Target.Abi).Enum.fields) |field| {
+    for (meta.fieldNames(Target.Abi)) |field| {
         try jws.arrayElem();
-        try jws.emitString(field.name);
+        try jws.emitString(field);
     }
     try jws.endArray();
 
@@ -84,10 +83,9 @@ pub fn cmdTargets(
 
     try jws.objectField("cpus");
     try jws.beginObject();
-    inline for (@typeInfo(Target.Cpu.Arch).Enum.fields) |field| {
-        try jws.objectField(field.name);
+    for (meta.tags(Target.Cpu.Arch)) |arch| {
+        try jws.objectField(@tagName(arch));
         try jws.beginObject();
-        const arch = @field(Target.Cpu.Arch, field.name);
         for (arch.allCpuModels()) |model| {
             try jws.objectField(model.name);
             try jws.beginArray();
@@ -105,10 +103,9 @@ pub fn cmdTargets(
 
     try jws.objectField("cpuFeatures");
     try jws.beginObject();
-    inline for (@typeInfo(Target.Cpu.Arch).Enum.fields) |field| {
-        try jws.objectField(field.name);
+    for (meta.tags(Target.Cpu.Arch)) |arch| {
+        try jws.objectField(@tagName(arch));
         try jws.beginArray();
-        const arch = @field(Target.Cpu.Arch, field.name);
         for (arch.allFeaturesList()) |feature| {
             try jws.arrayElem();
             try jws.emitString(feature.name);