Honor //go/config:linkmode for go_test (#3629)

Author: fmeum

docs/go/core/rules.md

@@ -391,7 +391,7 @@ This builds a set of tests that can be run with `bazel test`.<br><br>
 | <a id="go_test-goos"></a>goos |  Forces a binary to be cross-compiled for a specific operating system. It's             usually better to control this on the command line with <code>--platforms</code>.<br><br>            This disables cgo by default, since a cross-compiling C/C++ toolchain is             rarely available. To force cgo, set <code>pure</code> = <code>off</code>.<br><br>            See [Cross compilation] for more information.   | String | optional | "auto" |
 | <a id="go_test-gotags"></a>gotags |  Enables a list of build tags when evaluating [build constraints]. Useful for             conditional compilation.   | List of strings | optional | [] |
 | <a id="go_test-importpath"></a>importpath |  The import path of this test. Tests can't actually be imported, but this             may be used by [go_path] and other tools to report the location of source             files. This may be inferred from embedded libraries.   | String | optional | "" |
-| <a id="go_test-linkmode"></a>linkmode |  Determines how the binary should be built and linked. This accepts some of             the same values as `go build -buildmode` and works the same way.             <br><br>             <ul>             <li>`normal`: Builds a normal executable with position-dependent code.</li>             <li>`pie`: Builds a position-independent executable.</li>             <li>`plugin`: Builds a shared library that can be loaded as a Go plugin. Only supported on platforms that support plugins.</li>             <li>`c-shared`: Builds a shared library that can be linked into a C program.</li>             <li>`c-archive`: Builds an archive that can be linked into a C program.</li>             </ul>   | String | optional | "normal" |
+| <a id="go_test-linkmode"></a>linkmode |  Determines how the binary should be built and linked. This accepts some of             the same values as `go build -buildmode` and works the same way.             <br><br>             <ul>             <li>`auto` (default): Controlled by `//go/config:linkmode`, which defaults to `normal`.</li>             <li>`normal`: Builds a normal executable with position-dependent code.</li>             <li>`pie`: Builds a position-independent executable.</li>             <li>`plugin`: Builds a shared library that can be loaded as a Go plugin. Only supported on platforms that support plugins.</li>             <li>`c-shared`: Builds a shared library that can be linked into a C program.</li>             <li>`c-archive`: Builds an archive that can be linked into a C program.</li>             </ul>   | String | optional | "auto" |
 | <a id="go_test-msan"></a>msan |  Controls whether code is instrumented for memory sanitization. May be one of             <code>on</code>, <code>off</code>, or <code>auto</code>. Not available when cgo is             disabled. In most cases, it's better to control this on the command line with             <code>--@io_bazel_rules_go//go/config:msan</code>. See [mode attributes], specifically             [msan].   | String | optional | "auto" |
 | <a id="go_test-pure"></a>pure |  Controls whether cgo source code and dependencies are compiled and linked,             similar to setting <code>CGO_ENABLED</code>. May be one of <code>on</code>, <code>off</code>,             or <code>auto</code>. If <code>auto</code>, pure mode is enabled when no C/C++             toolchain is configured or when cross-compiling. It's usually better to             control this on the command line with             <code>--@io_bazel_rules_go//go/config:pure</code>. See [mode attributes], specifically             [pure].   | String | optional | "auto" |
 | <a id="go_test-race"></a>race |  Controls whether code is instrumented for race detection. May be one of             <code>on</code>, <code>off</code>, or <code>auto</code>. Not available when cgo is             disabled. In most cases, it's better to control this on the command line with             <code>--@io_bazel_rules_go//go/config:race</code>. See [mode attributes], specifically             [race].   | String | optional | "auto" |

go/private/rules/test.bzl

@@ -46,7 +46,7 @@ load(
 )
 load(
     "//go/private:mode.bzl",
-    "LINKMODE_NORMAL",
+    "LINKMODES",
 )
 load(
     "@bazel_skylib//lib:structs.bzl",
@@ -292,11 +292,13 @@ _go_test_kwargs = {
             """,
         ),
         "linkmode": attr.string(
-            default = LINKMODE_NORMAL,
+            default = "auto",
+            values = ["auto"] + LINKMODES,
             doc = """Determines how the binary should be built and linked. This accepts some of
             the same values as `go build -buildmode` and works the same way.
             <br><br>
             <ul>
+            <li>`auto` (default): Controlled by `//go/config:linkmode`, which defaults to `normal`.</li>
             <li>`normal`: Builds a normal executable with position-dependent code.</li>
             <li>`pie`: Builds a position-independent executable.</li>
             <li>`plugin`: Builds a shared library that can be loaded as a Go plugin. Only supported on platforms that support plugins.</li>

tests/core/go_binary/BUILD.bazel

@@ -108,6 +108,20 @@ linkmode_pie_wrapper(
     target = ":hello_nopie_bin",
 )
 
+go_test(
+    name = "hello_nopie_test_bin",
+    srcs = ["hello.go"],
+    cgo = True,
+    tags = ["manual"],
+)
+
+linkmode_pie_wrapper(
+    name = "hello_pie_setting_test_bin",
+    testonly = True,
+    tags = ["manual"],
+    target = ":hello_nopie_test_bin",
+)
+
 go_test(
     name = "pie_test",
     srcs = [
@@ -120,11 +134,13 @@ go_test(
             ":hello_nopie_bin",
             ":hello_pie_bin",
             ":hello_pie_setting_bin",
+            ":hello_pie_setting_test_bin",
         ],
         "@io_bazel_rules_go//go/platform:linux": [
             ":hello_nopie_bin",
             ":hello_pie_bin",
             ":hello_pie_setting_bin",
+            ":hello_pie_setting_test_bin",
         ],
         "//conditions:default": [],
     }),

tests/core/go_binary/pie_darwin_test.go

@@ -30,6 +30,28 @@ func TestPIE(t *testing.T) {
 	}
 
 	if m.Flags&macho.FlagPIE == 0 {
-		t.Error("ELF binary is not position-independent.")
+		t.Error("MachO binary is not position-independent.")
+	}
+}
+
+func TestPIESetting(t *testing.T) {
+	m, err := openMachO("tests/core/go_binary", "hello_pie_setting_bin")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if m.Flags&macho.FlagPIE == 0 {
+		t.Error("MachO binary is not position-independent.")
+	}
+}
+
+func TestPIESettingTest(t *testing.T) {
+	m, err := openMachO("tests/core/go_binary", "hello_pie_setting_test_bin")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if m.Flags&macho.FlagPIE == 0 {
+		t.Error("MachO binary is not position-independent.")
 	}
 }

tests/core/go_binary/pie_linux_test.go

@@ -35,6 +35,18 @@ func TestPIESetting(t *testing.T) {
 	}
 }
 
+func TestPIESettingTest(t *testing.T) {
+	e, err := openELF("tests/core/go_binary", "hello_pie_setting_test_bin")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// PIE binaries are implemented as shared libraries.
+	if e.Type != elf.ET_DYN {
+		t.Error("ELF binary is not position-independent.")
+	}
+}
+
 func TestPIE(t *testing.T) {
 	e, err := openELF("tests/core/go_binary", "hello_pie_bin")
 	if err != nil {