llvm: incremental Builder improvements

lib/std/Build/Step.zig

@@ -294,7 +294,7 @@ pub fn evalZigProcess(
     s: *Step,
     argv: []const []const u8,
     prog_node: *std.Progress.Node,
-) ![]const u8 {
+) !?[]const u8 {
     assert(argv.len != 0);
     const b = s.owner;
     const arena = b.allocator;
@@ -423,6 +423,8 @@ pub fn evalZigProcess(
         });
     }
 
+    if (s.cast(Compile)) |compile| if (compile.emit_bin == .no_emit) return result;
+
     return result orelse return s.fail(
         "the following command failed to communicate the compilation result:\n{s}",
         .{try allocPrintCmd(arena, null, argv)},

lib/std/Build/Step/Compile.zig

@@ -1997,18 +1997,19 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
         try zig_args.append(resolved_args_file);
     }
 
-    const output_bin_path = step.evalZigProcess(zig_args.items, prog_node) catch |err| switch (err) {
+    const maybe_output_bin_path = step.evalZigProcess(zig_args.items, prog_node) catch |err| switch (err) {
         error.NeedCompileErrorCheck => {
             assert(self.expect_errors.len != 0);
             try checkCompileErrors(self);
             return;
         },
         else => |e| return e,
     };
-    const output_dir = fs.path.dirname(output_bin_path).?;
 
     // Update generated files
-    {
+    if (maybe_output_bin_path) |output_bin_path| {
+        const output_dir = fs.path.dirname(output_bin_path).?;
+
         self.output_dirname_source.path = output_dir;
 
         self.output_path_source.path = b.pathJoin(

lib/std/Build/Step/TranslateC.zig

@@ -148,8 +148,8 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
 
     const output_path = try step.evalZigProcess(argv_list.items, prog_node);
 
-    self.out_basename = fs.path.basename(output_path);
-    const output_dir = fs.path.dirname(output_path).?;
+    self.out_basename = fs.path.basename(output_path.?);
+    const output_dir = fs.path.dirname(output_path.?).?;
 
     self.output_file.path = try fs.path.join(
         b.allocator,

lib/std/target.zig

@@ -1912,7 +1912,7 @@ pub const Target = struct {
         return switch (target.cpu.arch) {
             .amdgcn => 4,
             .x86 => switch (target.os.tag) {
-                .windows => 4,
+                .windows, .uefi => 4,
                 else => 16,
             },
             .arm,
@@ -1931,8 +1931,6 @@ pub const Target = struct {
             .bpfel,
             .mips64,
             .mips64el,
-            .powerpc64,
-            .powerpc64le,
             .riscv32,
             .riscv64,
             .sparc64,
@@ -1941,6 +1939,12 @@ pub const Target = struct {
             .wasm32,
             .wasm64,
             => 16,
+            .powerpc64,
+            .powerpc64le,
+            => switch (target.os.tag) {
+                else => 8,
+                .linux => 16,
+            },
             else => @divExact(target.ptrBitWidth(), 8),
         };
     }

src/Compilation.zig

@@ -1053,6 +1053,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
                     buf.appendSliceAssumeCapacity(",");
                 }
             }
+            if (buf.items.len == 0) break :blk "";
             assert(mem.endsWith(u8, buf.items, ","));
             buf.items[buf.items.len - 1] = 0;
             buf.shrinkAndFree(buf.items.len);