Commit 8c47dda7df2ff123699856eea513a266952b91bf | zig

author	Alex Rønne Petersen <alex@alexrp.com> 2025-08-03 16:13:01+02:00
committer	Alex Rønne Petersen <alex@alexrp.com> 2025-08-30 06:36:41+02:00
log	8c47dda7df2ff123699856eea513a266952b91bf
tree	d0b70cf17c85776ffb189e7fe3dcde7a25264a35
parent	c0cfe571f9723ec078e05c6aab5b1066d167f02e
signature	Signed by SSH key SHA256:7B/LJ7bpR1eX8aCXSr4mtd5M45VMPKcx9zY8e95b5QM

zig cc: pass CPU features to Clang using the new -Xclangas when assembling

Unfortunately, we cannot yet remove the special-casing for RISC-V CPU features,
so that code stays.

Closes #10411.

1 files changed, 37 insertions(+), 32 deletions(-)

src
- Compilation.zig

src/Compilation.zig+37-32

 @@ -6798,6 +6798,43 @@ pub fn addCCArgs(
         else => {},
     }
+    const xclang_flag = switch (ext) {
+        .assembly, .assembly_with_cpp => "-Xclangas",
+        else => "-Xclang",
+    };
+    if (target_util.clangSupportsTargetCpuArg(target)) {
+        if (target.cpu.model.llvm_name) |llvm_name| {
+            try argv.appendSlice(&[_][]const u8{
+                xclang_flag, "-target-cpu", xclang_flag, llvm_name,
+            });
+        }
+    }
+    // It would be really nice if there was a more compact way to communicate this info to Clang.
+    const all_features_list = target.cpu.arch.allFeaturesList();
+    try argv.ensureUnusedCapacity(all_features_list.len * 4);
+    for (all_features_list, 0..) |feature, index_usize| {
+        const index = @as(std.Target.Cpu.Feature.Set.Index, @intCast(index_usize));
+        const is_enabled = target.cpu.features.isEnabled(index);
+        if (feature.llvm_name) |llvm_name| {
+            // We communicate float ABI to Clang through the dedicated options.
+            if (std.mem.startsWith(u8, llvm_name, "soft-float") or
+                std.mem.startsWith(u8, llvm_name, "hard-float"))
+                continue;
+            // Ignore these until we figure out how to handle the concept of omitting features.
+            // See https://github.com/ziglang/zig/issues/23539
+            if (target_util.isDynamicAMDGCNFeature(target, feature)) continue;
+            argv.appendSliceAssumeCapacity(&[_][]const u8{ xclang_flag, "-target-feature", xclang_flag });
+            const plus_or_minus = "-+"[@intFromBool(is_enabled)];
+            const arg = try std.fmt.allocPrint(arena, "{c}{s}", .{ plus_or_minus, llvm_name });
+            argv.appendAssumeCapacity(arg);
+        }
+    }
     if (target.cpu.arch.isArm()) {
         try argv.append(if (target.cpu.arch.isThumb()) "-mthumb" else "-mno-thumb");
     }
 @@ -7134,38 +7171,6 @@ pub fn addCCArgs(
                 try argv.append(try std.fmt.allocPrint(arena, "-mcmodel={s}", .{@tagName(mod.code_model)}));
             }
-            if (target_util.clangSupportsTargetCpuArg(target)) {
-                if (target.cpu.model.llvm_name) |llvm_name| {
-                    try argv.appendSlice(&[_][]const u8{
-                        "-Xclang", "-target-cpu", "-Xclang", llvm_name,
-                    });
-                }
-            }
-            // It would be really nice if there was a more compact way to communicate this info to Clang.
-            const all_features_list = target.cpu.arch.allFeaturesList();
-            try argv.ensureUnusedCapacity(all_features_list.len * 4);
-            for (all_features_list, 0..) |feature, index_usize| {
-                const index = @as(std.Target.Cpu.Feature.Set.Index, @intCast(index_usize));
-                const is_enabled = target.cpu.features.isEnabled(index);
-                if (feature.llvm_name) |llvm_name| {
-                    // We communicate float ABI to Clang through the dedicated options.
-                    if (std.mem.startsWith(u8, llvm_name, "soft-float") or
-                        std.mem.startsWith(u8, llvm_name, "hard-float"))
-                        continue;
-                    // Ignore these until we figure out how to handle the concept of omitting features.
-                    // See https://github.com/ziglang/zig/issues/23539
-                    if (target_util.isDynamicAMDGCNFeature(target, feature)) continue;
-                    argv.appendSliceAssumeCapacity(&[_][]const u8{ "-Xclang", "-target-feature", "-Xclang" });
-                    const plus_or_minus = "-+"[@intFromBool(is_enabled)];
-                    const arg = try std.fmt.allocPrint(arena, "{c}{s}", .{ plus_or_minus, llvm_name });
-                    argv.appendAssumeCapacity(arg);
-                }
-            }
             {
                 var san_arg: std.ArrayListUnmanaged(u8) = .empty;
                 const prefix = "-fsanitize=";