From 893a4286569c9250c29eec8d1cff386ddbf38b3c Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Wed, 12 May 2021 11:26:37 +0200
Subject: stage2: Drop LLVM's host CPU detection method as fallback

The CPU detection code is nearly at feature parity, we do support
detecting the native CPU on Sparc systems and macos, our ARM/AArch64
model list is quite comprehensive and so is our PPC one.

The only missing pieces are:
- ARM32 detection on Darwin hosts (I don't think anybody is planning on
  running the compiler on a old-ass iPhone)
- s390x detection on Linux hosts, this can be easily added at a later
  stage.
---
 src/main.zig | 82 +-----------------------------------------------------------
 1 file changed, 1 insertion(+), 81 deletions(-)

(limited to 'src/main.zig')

diff --git a/src/main.zig b/src/main.zig
index a0a11bbbbc..dc98044642 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -3396,88 +3396,8 @@ test "fds" {
     gimmeMoreOfThoseSweetSweetFileDescriptors();
 }
 
-fn detectNativeCpuWithLLVM(
-    arch: std.Target.Cpu.Arch,
-    llvm_cpu_name_z: ?[*:0]const u8,
-    llvm_cpu_features_opt: ?[*:0]const u8,
-) !std.Target.Cpu {
-    var result = std.Target.Cpu.baseline(arch);
-
-    if (llvm_cpu_name_z) |cpu_name_z| {
-        const llvm_cpu_name = mem.spanZ(cpu_name_z);
-
-        for (arch.allCpuModels()) |model| {
-            const this_llvm_name = model.llvm_name orelse continue;
-            if (mem.eql(u8, this_llvm_name, llvm_cpu_name)) {
-                // Here we use the non-dependencies-populated set,
-                // so that subtracting features later in this function
-                // affect the prepopulated set.
-                result = std.Target.Cpu{
-                    .arch = arch,
-                    .model = model,
-                    .features = model.features,
-                };
-                break;
-            }
-        }
-    }
-
-    const all_features = arch.allFeaturesList();
-
-    if (llvm_cpu_features_opt) |llvm_cpu_features| {
-        var it = mem.tokenize(mem.spanZ(llvm_cpu_features), ",");
-        while (it.next()) |decorated_llvm_feat| {
-            var op: enum {
-                add,
-                sub,
-            } = undefined;
-            var llvm_feat: []const u8 = undefined;
-            if (mem.startsWith(u8, decorated_llvm_feat, "+")) {
-                op = .add;
-                llvm_feat = decorated_llvm_feat[1..];
-            } else if (mem.startsWith(u8, decorated_llvm_feat, "-")) {
-                op = .sub;
-                llvm_feat = decorated_llvm_feat[1..];
-            } else {
-                return error.InvalidLlvmCpuFeaturesFormat;
-            }
-            for (all_features) |feature, index_usize| {
-                const this_llvm_name = feature.llvm_name orelse continue;
-                if (mem.eql(u8, llvm_feat, this_llvm_name)) {
-                    const index = @intCast(std.Target.Cpu.Feature.Set.Index, index_usize);
-                    switch (op) {
-                        .add => result.features.addFeature(index),
-                        .sub => result.features.removeFeature(index),
-                    }
-                    break;
-                }
-            }
-        }
-    }
-
-    result.features.populateDependencies(all_features);
-    return result;
-}
-
 fn detectNativeTargetInfo(gpa: *Allocator, cross_target: std.zig.CrossTarget) !std.zig.system.NativeTargetInfo {
-    var info = try std.zig.system.NativeTargetInfo.detect(gpa, cross_target);
-    if (info.cpu_detection_unimplemented) {
-        const arch = std.Target.current.cpu.arch;
-
-        // We want to just use detected_info.target but implementing
-        // CPU model & feature detection is todo so here we rely on LLVM.
-        // https://github.com/ziglang/zig/issues/4591
-        if (!build_options.have_llvm)
-            fatal("CPU features detection is not yet available for {s} without LLVM extensions", .{@tagName(arch)});
-
-        const llvm = @import("codegen/llvm/bindings.zig");
-        const llvm_cpu_name = llvm.GetHostCPUName();
-        const llvm_cpu_features = llvm.GetNativeFeatures();
-        info.target.cpu = try detectNativeCpuWithLLVM(arch, llvm_cpu_name, llvm_cpu_features);
-        cross_target.updateCpuFeatures(&info.target.cpu.features);
-        info.target.cpu.arch = cross_target.getCpuArch();
-    }
-    return info;
+    return std.zig.system.NativeTargetInfo.detect(gpa, cross_target);
 }
 
 /// Indicate that we are now terminating with a successful exit code.
-- 
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