self-hosted: first passing test

 * introduce std.atomic.Int
 * add src-self-hosted/test.zig which is tested by the main test suite
   - it fully utilizes the multithreaded async/await event loop so the
     tests should Go Fast
 * `stage2/bin/zig build-obj test.zig` is able to spit out an error if 2 exported
   functions collide
 * ability for `zig test` to accept `--object` and `--assembly`
   arguments
 * std.build: TestStep supports addLibPath and addObjectFile

3 files changed, 43 insertions, 0 deletions

diff --git a/std/atomic/index.zig b/std/atomic/index.zig
index c0ea5be183..cf344a8231 100644
--- a/std/atomic/index.zig
+++ b/std/atomic/index.zig
@@ -1,9 +1,11 @@
 pub const Stack = @import("stack.zig").Stack;
 pub const QueueMpsc = @import("queue_mpsc.zig").QueueMpsc;
 pub const QueueMpmc = @import("queue_mpmc.zig").QueueMpmc;
+pub const Int = @import("int.zig").Int;
 
 test "std.atomic" {
     _ = @import("stack.zig");
     _ = @import("queue_mpsc.zig");
     _ = @import("queue_mpmc.zig");
+    _ = @import("int.zig");
 }
diff --git a/std/atomic/int.zig b/std/atomic/int.zig
new file mode 100644
index 0000000000..7042bca78d
--- /dev/null
+++ b/std/atomic/int.zig
@@ -0,0 +1,19 @@
+const builtin = @import("builtin");
+const AtomicOrder = builtin.AtomicOrder;
+
+/// Thread-safe, lock-free integer
+pub fn Int(comptime T: type) type {
+    return struct {
+        value: T,
+
+        pub const Self = this;
+
+        pub fn init(init_val: T) Self {
+            return Self{ .value = init_val };
+        }
+
+        pub fn next(self: *Self) T {
+            return @atomicRmw(T, &self.value, builtin.AtomicRmwOp.Add, 1, AtomicOrder.SeqCst);
+        }
+    };
+}
diff --git a/std/build.zig b/std/build.zig
index 24fa85383a..cea760e8a2 100644
--- a/std/build.zig
+++ b/std/build.zig
@@ -1596,6 +1596,8 @@ pub const TestStep = struct {
     target: Target,
     exec_cmd_args: ?[]const ?[]const u8,
     include_dirs: ArrayList([]const u8),
+    lib_paths: ArrayList([]const u8),
+    object_files: ArrayList([]const u8),
 
     pub fn init(builder: *Builder, root_src: []const u8) TestStep {
         const step_name = builder.fmt("test {}", root_src);
@@ -1611,9 +1613,15 @@ pub const TestStep = struct {
             .target = Target{ .Native = {} },
             .exec_cmd_args = null,
             .include_dirs = ArrayList([]const u8).init(builder.allocator),
+            .lib_paths = ArrayList([]const u8).init(builder.allocator),
+            .object_files = ArrayList([]const u8).init(builder.allocator),
         };
     }
 
+    pub fn addLibPath(self: *TestStep, path: []const u8) void {
+        self.lib_paths.append(path) catch unreachable;
+    }
+
     pub fn setVerbose(self: *TestStep, value: bool) void {
         self.verbose = value;
     }
@@ -1638,6 +1646,10 @@ pub const TestStep = struct {
         self.filter = text;
     }
 
+    pub fn addObjectFile(self: *TestStep, path: []const u8) void {
+        self.object_files.append(path) catch unreachable;
+    }
+
     pub fn setTarget(self: *TestStep, target_arch: builtin.Arch, target_os: builtin.Os, target_environ: builtin.Environ) void {
         self.target = Target{
             .Cross = CrossTarget{
@@ -1699,6 +1711,11 @@ pub const TestStep = struct {
             try zig_args.append(self.name_prefix);
         }
 
+        for (self.object_files.toSliceConst()) |object_file| {
+            try zig_args.append("--object");
+            try zig_args.append(builder.pathFromRoot(object_file));
+        }
+
         {
             var it = self.link_libs.iterator();
             while (true) {
@@ -1734,6 +1751,11 @@ pub const TestStep = struct {
             try zig_args.append(rpath);
         }
 
+        for (self.lib_paths.toSliceConst()) |lib_path| {
+            try zig_args.append("--library-path");
+            try zig_args.append(lib_path);
+        }
+
         for (builder.lib_paths.toSliceConst()) |lib_path| {
             try zig_args.append("--library-path");
             try zig_args.append(lib_path);