From 280ced66eb712f5c74835b10fa6ba0bd915ee96b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Fri, 29 Nov 2024 01:31:49 +0100
Subject: [PATCH] std.Target: Define and use lime1 as the baseline CPU model
 for WebAssembly.

See: https://github.com/WebAssembly/tool-conventions/pull/235

This is not *quite* using the same features as the spec'd lime1 model because
LLVM 19 doesn't have the level of feature granularity that we need for that.
This will be fixed once we upgrade to LLVM 20.

Part of #21818.
---
 build.zig                     | 14 +++++++-------
 lib/std/Target.zig            |  2 +-
 lib/std/Target/wasm.zig       | 12 ++++++++++++
 src/Compilation.zig           |  5 -----
 tools/update_cpu_features.zig | 14 ++++++++++++++
 5 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/build.zig b/build.zig
index a513a993998fc5d87ea7362d3418d9313b7c47be..24d30f2ec2fc09c4642b208c8782e8b3612403c2 100644
--- a/build.zig
+++ b/build.zig
@@ -594,15 +594,14 @@ pub fn build(b: *std.Build) !void {
 fn addWasiUpdateStep(b: *std.Build, version: [:0]const u8) !void {
     const semver = try std.SemanticVersion.parse(version);
 
-    var target_query: std.Target.Query = .{
-        .cpu_arch = .wasm32,
-        .os_tag = .wasi,
-    };
-    target_query.cpu_features_add.addFeature(@intFromEnum(std.Target.wasm.Feature.bulk_memory));
-
     const exe = addCompilerStep(b, .{
         .optimize = .ReleaseSmall,
-        .target = b.resolveTargetQuery(target_query),
+        .target = b.resolveTargetQuery(std.Target.Query.parse(.{
+            .arch_os_abi = "wasm32-wasi",
+            // `extended_const` is not supported by the `wasm-opt` version in CI.
+            // `nontrapping_fptoint` is not supported by `wasm2c`.
+            .cpu_features = "baseline-extended_const-nontrapping_fptoint",
+        }) catch unreachable),
     });
 
     const exe_options = b.addOptions();
@@ -644,6 +643,7 @@ fn addWasiUpdateStep(b: *std.Build, version: [:0]const u8) !void {
         "wasm-opt",
         "-Oz",
         "--enable-bulk-memory",
+        "--enable-mutable-globals",
         "--enable-sign-ext",
     });
     run_opt.addArtifactArg(exe);
diff --git a/lib/std/Target.zig b/lib/std/Target.zig
index 2bb8a3361a80e81c5bee8a6fcbd13b4711d35368..ce6eaa9f2f58c799d3afc60e9bc8b0a2ed58a7de 100644
--- a/lib/std/Target.zig
+++ b/lib/std/Target.zig
@@ -2012,7 +2012,7 @@ pub const Cpu = struct {
                     else => generic(arch),
                 },
                 .xcore => &xcore.cpu.xs1b_generic,
-                .wasm32, .wasm64 => &wasm.cpu.generic,
+                .wasm32, .wasm64 => &wasm.cpu.lime1,
 
                 else => generic(arch),
             };
diff --git a/lib/std/Target/wasm.zig b/lib/std/Target/wasm.zig
index 0507333d960c2560839778760cc8bc379d903a35..eba4f9f01fa2b742b49e3c72b3bdd000948d4df4 100644
--- a/lib/std/Target/wasm.zig
+++ b/lib/std/Target/wasm.zig
@@ -139,6 +139,18 @@ pub const cpu = struct {
             .sign_ext,
         }),
     };
+    pub const lime1: CpuModel = .{
+        .name = "lime1",
+        .llvm_name = null,
+        .features = featureSet(&[_]Feature{
+            .bulk_memory,
+            .extended_const,
+            .multivalue,
+            .mutable_globals,
+            .nontrapping_fptoint,
+            .sign_ext,
+        }),
+    };
     pub const mvp: CpuModel = .{
         .name = "mvp",
         .llvm_name = "mvp",
diff --git a/src/Compilation.zig b/src/Compilation.zig
index b85033264ac50c3db199ddaaafb2c06b91410b7b..ac8fb8a59bcee43bd4d1d31b6c0efb35d7fc80e1 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -4150,14 +4150,9 @@ fn workerDocsWasmFallible(comp: *Compilation, prog_node: std.Progress.Node) anye
             .os_tag = .freestanding,
             .cpu_features_add = std.Target.wasm.featureSet(&.{
                 .atomics,
-                .bulk_memory,
                 // .extended_const, not supported by Safari
-                .multivalue,
-                .mutable_globals,
-                .nontrapping_fptoint,
                 .reference_types,
                 //.relaxed_simd, not supported by Firefox or Safari
-                .sign_ext,
                 // observed to cause Error occured during wast conversion :
                 // Unknown operator: 0xfd058 in Firefox 117
                 //.simd128,
diff --git a/tools/update_cpu_features.zig b/tools/update_cpu_features.zig
index 065d40d3f4b4c3bfbe11afdbc63003cd220330f3..5a4e06354f652490a62c95f6e4655426cae3c3f0 100644
--- a/tools/update_cpu_features.zig
+++ b/tools/update_cpu_features.zig
@@ -1033,6 +1033,20 @@ const llvm_targets = [_]LlvmTarget{
         .zig_name = "wasm",
         .llvm_name = "WebAssembly",
         .td_name = "WebAssembly.td",
+        .extra_cpus = &.{
+            .{
+                .llvm_name = null,
+                .zig_name = "lime1",
+                .features = &.{
+                    "bulk_memory",
+                    "extended_const",
+                    "multivalue",
+                    "mutable_globals",
+                    "nontrapping_fptoint",
+                    "sign_ext",
+                },
+            },
+        },
     },
     .{
         .zig_name = "x86",
-- 
2.54.0