make the build runner and test runner talk to each other

std.Build.addTest creates a CompileStep as before, however, this kind of
step no longer actually runs the unit tests. Instead it only compiles
it, and one must additionally create a RunStep from the CompileStep in
order to actually run the tests.

RunStep gains integration with the default test runner, which now
supports the standard --listen=- argument in order to communicate over
stdin and stdout. It also reports test statistics; how many passed,
failed, and leaked, as well as directly associating the relevant stderr
with the particular test name that failed.

This separation of CompileStep and RunStep means that
`CompileStep.Kind.test_exe` is no longer needed, and therefore has been
removed in this commit.

 * build runner: show unit test statistics in build summary
 * added Step.writeManifest since many steps want to treat it as a
   warning and emit the same message if it fails.
 * RunStep: fixed error message that prints the failed command printing
   the original argv and not the adjusted argv in case an interpreter
   was used.
 * RunStep: fixed not passing the command line arguments to the
   interpreter.
 * move src/Server.zig to std.zig.Server so that the default test runner
   can use it.
 * the simpler test runner function which is used by work-in-progress
   backends now no longer prints to stderr, which is necessary in order
   for the build runner to not print the stderr as a warning message.

3 files changed, 10 insertions, 133 deletions

diff --git a/src/Server.zig b/src/Server.zig
deleted file mode 100644
index a25dc93857..0000000000
--- a/src/Server.zig
+++ /dev/null
@@ -1,113 +0,0 @@
-in: std.fs.File,
-out: std.fs.File,
-receive_fifo: std.fifo.LinearFifo(u8, .Dynamic),
-
-pub const Options = struct {
-    gpa: Allocator,
-    in: std.fs.File,
-    out: std.fs.File,
-};
-
-pub fn init(options: Options) !Server {
-    var s: Server = .{
-        .in = options.in,
-        .out = options.out,
-        .receive_fifo = std.fifo.LinearFifo(u8, .Dynamic).init(options.gpa),
-    };
-    try s.serveStringMessage(.zig_version, build_options.version);
-    return s;
-}
-
-pub fn deinit(s: *Server) void {
-    s.receive_fifo.deinit();
-    s.* = undefined;
-}
-
-pub fn receiveMessage(s: *Server) !InMessage.Header {
-    const Header = InMessage.Header;
-    const fifo = &s.receive_fifo;
-
-    while (true) {
-        const buf = fifo.readableSlice(0);
-        assert(fifo.readableLength() == buf.len);
-        if (buf.len >= @sizeOf(Header)) {
-            const header = @ptrCast(*align(1) const Header, buf[0..@sizeOf(Header)]);
-            if (header.bytes_len != 0)
-                return error.InvalidClientMessage;
-            const result = header.*;
-            fifo.discard(@sizeOf(Header));
-            return result;
-        }
-
-        const write_buffer = try fifo.writableWithSize(256);
-        const amt = try s.in.read(write_buffer);
-        fifo.update(amt);
-    }
-}
-
-pub fn serveStringMessage(s: *Server, tag: OutMessage.Tag, msg: []const u8) !void {
-    return s.serveMessage(.{
-        .tag = tag,
-        .bytes_len = @intCast(u32, msg.len),
-    }, &.{msg});
-}
-
-pub fn serveMessage(
-    s: *const Server,
-    header: OutMessage.Header,
-    bufs: []const []const u8,
-) !void {
-    var iovecs: [10]std.os.iovec_const = undefined;
-    iovecs[0] = .{
-        .iov_base = @ptrCast([*]const u8, &header),
-        .iov_len = @sizeOf(OutMessage.Header),
-    };
-    for (bufs, iovecs[1 .. bufs.len + 1]) |buf, *iovec| {
-        iovec.* = .{
-            .iov_base = buf.ptr,
-            .iov_len = buf.len,
-        };
-    }
-    try s.out.writevAll(iovecs[0 .. bufs.len + 1]);
-}
-
-pub fn serveEmitBinPath(
-    s: *Server,
-    fs_path: []const u8,
-    header: std.zig.Server.Message.EmitBinPath,
-) !void {
-    try s.serveMessage(.{
-        .tag = .emit_bin_path,
-        .bytes_len = @intCast(u32, fs_path.len + @sizeOf(std.zig.Server.Message.EmitBinPath)),
-    }, &.{
-        std.mem.asBytes(&header),
-        fs_path,
-    });
-}
-
-pub fn serveErrorBundle(s: *Server, error_bundle: std.zig.ErrorBundle) !void {
-    const eb_hdr: std.zig.Server.Message.ErrorBundle = .{
-        .extra_len = @intCast(u32, error_bundle.extra.len),
-        .string_bytes_len = @intCast(u32, error_bundle.string_bytes.len),
-    };
-    const bytes_len = @sizeOf(std.zig.Server.Message.ErrorBundle) +
-        4 * error_bundle.extra.len + error_bundle.string_bytes.len;
-    try s.serveMessage(.{
-        .tag = .error_bundle,
-        .bytes_len = @intCast(u32, bytes_len),
-    }, &.{
-        std.mem.asBytes(&eb_hdr),
-        // TODO: implement @ptrCast between slices changing the length
-        std.mem.sliceAsBytes(error_bundle.extra),
-        error_bundle.string_bytes,
-    });
-}
-
-const OutMessage = std.zig.Server.Message;
-const InMessage = std.zig.Client.Message;
-
-const Server = @This();
-const std = @import("std");
-const build_options = @import("build_options");
-const Allocator = std.mem.Allocator;
-const assert = std.debug.assert;
diff --git a/src/main.zig b/src/main.zig
index e0283143d0..9602a5cd31 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -10,6 +10,7 @@ const ArrayList = std.ArrayList;
 const Ast = std.zig.Ast;
 const warn = std.log.warn;
 const ThreadPool = std.Thread.Pool;
+const cleanExit = std.process.cleanExit;
 
 const tracy = @import("tracy.zig");
 const Compilation = @import("Compilation.zig");
@@ -26,7 +27,7 @@ const target_util = @import("target.zig");
 const crash_report = @import("crash_report.zig");
 const Module = @import("Module.zig");
 const AstGen = @import("AstGen.zig");
-const Server = @import("Server.zig");
+const Server = std.zig.Server;
 
 pub const std_options = struct {
     pub const wasiCwd = wasi_cwd;
@@ -3545,6 +3546,7 @@ fn serve(
         .gpa = gpa,
         .in = in,
         .out = out,
+        .zig_version = build_options.version,
     });
     defer server.deinit();
 
@@ -3656,8 +3658,8 @@ fn serve(
                     );
                 }
             },
-            _ => {
-                @panic("TODO unrecognized message from client");
+            else => {
+                fatal("unrecognized message from client: 0x{x}", .{@enumToInt(hdr.tag)});
             },
         }
     }
@@ -5624,19 +5626,6 @@ fn detectNativeTargetInfo(cross_target: std.zig.CrossTarget) !std.zig.system.Nat
     return std.zig.system.NativeTargetInfo.detect(cross_target);
 }
 
-/// Indicate that we are now terminating with a successful exit code.
-/// In debug builds, this is a no-op, so that the calling code's
-/// cleanup mechanisms are tested and so that external tools that
-/// check for resource leaks can be accurate. In release builds, this
-/// calls exit(0), and does not return.
-pub fn cleanExit() void {
-    if (builtin.mode == .Debug) {
-        return;
-    } else {
-        process.exit(0);
-    }
-}
-
 const usage_ast_check =
     \\Usage: zig ast-check [file]
     \\
diff --git a/src/objcopy.zig b/src/objcopy.zig
index e821a94b59..c3305e8c04 100644
--- a/src/objcopy.zig
+++ b/src/objcopy.zig
@@ -8,8 +8,8 @@ const assert = std.debug.assert;
 
 const main = @import("main.zig");
 const fatal = main.fatal;
-const cleanExit = main.cleanExit;
-const Server = @import("Server.zig");
+const Server = std.zig.Server;
+const build_options = @import("build_options");
 
 pub fn cmdObjCopy(
     gpa: Allocator,
@@ -116,6 +116,7 @@ pub fn cmdObjCopy(
             .gpa = gpa,
             .in = std.io.getStdIn(),
             .out = std.io.getStdOut(),
+            .zig_version = build_options.version,
         });
         defer server.deinit();
 
@@ -124,7 +125,7 @@ pub fn cmdObjCopy(
             const hdr = try server.receiveMessage();
             switch (hdr.tag) {
                 .exit => {
-                    return cleanExit();
+                    return std.process.cleanExit();
                 },
                 .update => {
                     if (seen_update) {
@@ -144,7 +145,7 @@ pub fn cmdObjCopy(
             }
         }
     }
-    return cleanExit();
+    return std.process.cleanExit();
 }
 
 const usage =