initial implementation of macOS crypto backend

eng/_util/buildutil/buildutil.go

@@ -91,6 +91,7 @@ func AppendExperimentEnv(experiment string) {
 	if strings.Contains(experiment, "opensslcrypto") ||
 		strings.Contains(experiment, "cngcrypto") ||
 		strings.Contains(experiment, "boringcrypto") ||
+		strings.Contains(experiment, "darwincrypto") ||
 		strings.Contains(experiment, "systemcrypto") {
 
 		experiment += ",allowcryptofallback"
@@ -103,3 +104,19 @@ func AppendExperimentEnv(experiment string) {
 		panic(err)
 	}
 }
+
+// UnassignGOROOT unsets the GOROOT env var if it is set.
+//
+// Setting GOROOT explicitly in the environment has not been necessary since Go
+// 1.9 (https://go.dev/doc/go1.9#goroot), but a dev or build machine may still
+// have it set. It interferes with attempts to run the built Go (such as when
+// building the race runtime), so remove the explicit GOROOT if set.
+func UnassignGOROOT() error {
+	if explicitRoot, ok := os.LookupEnv("GOROOT"); ok {
+		fmt.Printf("---- Removing explicit GOROOT from environment: %v\n", explicitRoot)
+		if err := os.Unsetenv("GOROOT"); err != nil {
+			return err
+		}
+	}
+	return nil
+}

eng/_util/cmd/build/build.go

@@ -138,15 +138,8 @@ func build(o *options) error {
 	}
 	fmt.Printf("---- Target platform: %v_%v\n", targetOS, targetArch)
 
-	// Setting GOROOT explicitly in the environment has not been necessary since Go 1.9
-	// (https://go.dev/doc/go1.9#goroot), but a dev or build machine may still have it set. It
-	// interferes with attempts to run the built Go (such as when building the race runtime), so
-	// remove the explicit GOROOT if set.
-	if explicitRoot, ok := os.LookupEnv("GOROOT"); ok {
-		fmt.Printf("---- Removing explicit GOROOT from environment: %v\n", explicitRoot)
-		if err := os.Unsetenv("GOROOT"); err != nil {
-			return err
-		}
+	if err := buildutil.UnassignGOROOT(); err != nil {
+		return err
 	}
 
 	// The upstream build scripts in {repo-root}/src require your working directory to be src, or

eng/_util/cmd/run-builder/run-builder.go

@@ -105,6 +105,10 @@ func main() {
 		env("GO_TEST_TIMEOUT_SCALE", strconv.Itoa(timeoutScale))
 	}
 
+	if err := buildutil.UnassignGOROOT(); err != nil {
+		log.Fatal(err)
+	}
+
 	buildCmdline := []string{"pwsh", "eng/run.ps1", "build"}
 
 	// run.ps1 compiles Go code, so we can't use the experiment yet. We must pass the experiment

eng/pipeline/stages/go-builder-matrix-stages.yml

@@ -81,6 +81,13 @@ stages:
             - { os: linux, arch: arm64, config: buildandpack }
         - ${{ if parameters.innerloop }}:
           - { os: darwin, arch: amd64, config: devscript }
+          - { os: darwin, arch: amd64, config: test }
+          - { experiment: darwincrypto, os: darwin, arch: amd64, config: test }
+          - { experiment: darwincrypto, os: darwin, arch: amd64, config: test, fips: true }
+          - { os: darwin, arch: arm64, config: devscript }
+          - { os: darwin, arch: arm64, config: test }
+          - { experiment: darwincrypto, os: darwin, arch: arm64, config: test }
+          - { experiment: darwincrypto, os: darwin, arch: arm64, config: test, fips: true }
           - { os: linux, arch: amd64, config: devscript }
           - { os: linux, arch: amd64, config: test }
           - { os: linux, arch: amd64, config: test, distro: ubuntu }

eng/pipeline/stages/pool-2.yml

@@ -53,5 +53,9 @@ stages:
 
         ${{ elseif eq(parameters.os, 'darwin') }}:
           # https://learn.microsoft.com/en-us/azure/devops/pipelines/agents/hosted?view=azure-devops&tabs=yaml#software
-          vmImage: 'macos-14'
-          os: macOs
+          ${{ if eq(parameters.hostArch, 'amd64') }}:
+            vmImage: 'macos-14'
+            os: macOS
+          ${{ else }}:
+            vmImage: 'macos-latest-internal'
+            os: macOS

patches/0001-Add-systemcrypto-GOEXPERIMENT.patch

@@ -11,18 +11,18 @@ information about the behavior.
 Includes new tests in "build_test.go" and "buildbackend_test.go" to help
 maintain this feature. For more information, see the test files.
 ---
- src/cmd/go/internal/modindex/build.go         | 54 ++++++++++++++
- src/cmd/go/internal/modindex/build_test.go    | 73 +++++++++++++++++++
- src/go/build/build.go                         | 54 ++++++++++++++
- src/go/build/buildbackend_test.go             | 66 +++++++++++++++++
+ src/cmd/go/internal/modindex/build.go         | 57 +++++++++++++
+ src/cmd/go/internal/modindex/build_test.go    | 73 ++++++++++++++++
+ src/go/build/build.go                         | 57 +++++++++++++
+ src/go/build/buildbackend_test.go             | 84 +++++++++++++++++++
  .../testdata/backendtags_openssl/main.go      |  3 +
  .../testdata/backendtags_openssl/openssl.go   |  3 +
  .../build/testdata/backendtags_system/main.go |  3 +
  .../backendtags_system/systemcrypto.go        |  3 +
- .../goexperiment/exp_systemcrypto_off.go      |  9 +++
- .../goexperiment/exp_systemcrypto_on.go       |  9 +++
+ .../goexperiment/exp_systemcrypto_off.go      |  9 ++
+ .../goexperiment/exp_systemcrypto_on.go       |  9 ++
  src/internal/goexperiment/flags.go            | 15 ++++
- 11 files changed, 292 insertions(+)
+ 11 files changed, 316 insertions(+)
  create mode 100644 src/cmd/go/internal/modindex/build_test.go
  create mode 100644 src/go/build/buildbackend_test.go
  create mode 100644 src/go/build/testdata/backendtags_openssl/main.go
@@ -33,16 +33,17 @@ maintain this feature. For more information, see the test files.
  create mode 100644 src/internal/goexperiment/exp_systemcrypto_on.go
 
 diff --git a/src/cmd/go/internal/modindex/build.go b/src/cmd/go/internal/modindex/build.go
-index b57f2f6368f0fe..9ddde1ce9a2286 100644
+index b4dacb0f523a8d..4315c288d10cb3 100644
 --- a/src/cmd/go/internal/modindex/build.go
 +++ b/src/cmd/go/internal/modindex/build.go
-@@ -880,13 +880,67 @@ func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
+@@ -886,13 +886,70 @@ func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
  		name = "goexperiment.boringcrypto" // boringcrypto is an old name for goexperiment.boringcrypto
  	}
 
 +	const system = "goexperiment.systemcrypto"
 +	const openssl = "goexperiment.opensslcrypto"
 +	const cng = "goexperiment.cngcrypto"
++	const darwin = "goexperiment.darwincrypto"
 +	const boring = "goexperiment.boringcrypto"
 +	// Implement the SystemCrypto GOEXPERIMENT logic. This is done here rather
 +	// than during GOEXPERIMENT parsing so "-tags goexperiment.systemcrypto"
@@ -63,11 +64,12 @@ index b57f2f6368f0fe..9ddde1ce9a2286 100644
 +	satisfiedByAnyBackend := name == system
 +	satisfiedBySystemCrypto :=
 +		(ctxt.GOOS == "linux" && name == openssl) ||
-+			(ctxt.GOOS == "windows" && name == cng)
++			(ctxt.GOOS == "windows" && name == cng) ||
++			(ctxt.GOOS == "darwin" && name == darwin)
 +	satisfiedBy := func(tag string) bool {
 +		if satisfiedByAnyBackend {
 +			switch tag {
-+			case openssl, cng, boring:
++			case openssl, cng, darwin, boring:
 +				return true
 +			}
 +		}
@@ -81,6 +83,7 @@ index b57f2f6368f0fe..9ddde1ce9a2286 100644
 +		if satisfiedByAnyBackend {
 +			allTags[openssl] = true
 +			allTags[cng] = true
++			allTags[darwin] = true
 +			allTags[boring] = true
 +		}
 +		if satisfiedBySystemCrypto {
@@ -184,16 +187,17 @@ index 00000000000000..1756c5d027fee0
 +	}
 +}
 diff --git a/src/go/build/build.go b/src/go/build/build.go
-index dd6cdc903a21a8..48adcfed5cf3cb 100644
+index 9ffffda08a99b1..78fd536fa6a6d1 100644
 --- a/src/go/build/build.go
 +++ b/src/go/build/build.go
-@@ -1947,13 +1947,67 @@ func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
+@@ -1984,13 +1984,70 @@ func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
  		name = "goexperiment.boringcrypto" // boringcrypto is an old name for goexperiment.boringcrypto
  	}
 
 +	const system = "goexperiment.systemcrypto"
 +	const openssl = "goexperiment.opensslcrypto"
 +	const cng = "goexperiment.cngcrypto"
++	const darwin = "goexperiment.darwincrypto"
 +	const boring = "goexperiment.boringcrypto"
 +	// Implement the SystemCrypto GOEXPERIMENT logic. This is done here rather
 +	// than during GOEXPERIMENT parsing so "-tags goexperiment.systemcrypto"
@@ -214,11 +218,12 @@ index dd6cdc903a21a8..48adcfed5cf3cb 100644
 +	satisfiedByAnyBackend := name == system
 +	satisfiedBySystemCrypto :=
 +		(ctxt.GOOS == "linux" && name == openssl) ||
-+			(ctxt.GOOS == "windows" && name == cng)
++			(ctxt.GOOS == "windows" && name == cng) ||
++			(ctxt.GOOS == "darwin" && name == darwin)
 +	satisfiedBy := func(tag string) bool {
 +		if satisfiedByAnyBackend {
 +			switch tag {
-+			case openssl, cng, boring:
++			case openssl, cng, darwin, boring:
 +				return true
 +			}
 +		}
@@ -232,6 +237,7 @@ index dd6cdc903a21a8..48adcfed5cf3cb 100644
 +		if satisfiedByAnyBackend {
 +			allTags[openssl] = true
 +			allTags[cng] = true
++			allTags[darwin] = true
 +			allTags[boring] = true
 +		}
 +		if satisfiedBySystemCrypto {
@@ -257,10 +263,10 @@ index dd6cdc903a21a8..48adcfed5cf3cb 100644
  		}
 diff --git a/src/go/build/buildbackend_test.go b/src/go/build/buildbackend_test.go
 new file mode 100644
-index 00000000000000..a22abbb42e37c0
+index 00000000000000..aa3c5f1007ed79
 --- /dev/null
 +++ b/src/go/build/buildbackend_test.go
-@@ -0,0 +1,66 @@
+@@ -0,0 +1,84 @@
 +// Copyright 2023 The Go Authors. All rights reserved.
 +// Use of this source code is governed by a BSD-style
 +// license that can be found in the LICENSE file.
@@ -318,14 +324,32 @@ index 00000000000000..a22abbb42e37c0
 +	if err != nil {
 +		t.Fatal(err)
 +	}
-+	want = []string{"goexperiment.boringcrypto", "goexperiment.cngcrypto", "goexperiment.opensslcrypto", "goexperiment.systemcrypto"}
++	want = []string{"goexperiment.boringcrypto", "goexperiment.cngcrypto", "goexperiment.darwincrypto", "goexperiment.opensslcrypto", "goexperiment.systemcrypto"}
 +	if !reflect.DeepEqual(p.AllTags, want) {
 +		t.Errorf("AllTags = %v, want %v", p.AllTags, want)
 +	}
 +	wantFiles = []string{"main.go", "systemcrypto.go"}
 +	if !reflect.DeepEqual(p.GoFiles, wantFiles) {
 +		t.Errorf("GoFiles = %v, want %v", p.GoFiles, wantFiles)
 +	}
++
++	ctxt.GOARCH = "amd64"
++	ctxt.GOOS = "darwin"
++	ctxt.BuildTags = []string{"goexperiment.darwincrypto"}
++	p, err = ctxt.ImportDir("testdata/backendtags_openssl", 0)
++	if err != nil {
++		t.Fatal(err)
++	}
++	// Given the current GOOS (darwin), systemcrypto would not affect the
++	// decision, so we don't want it to be included in AllTags.
++	want = []string{"goexperiment.opensslcrypto"}
++	if !reflect.DeepEqual(p.AllTags, want) {
++		t.Errorf("AllTags = %v, want %v", p.AllTags, want)
++	}
++	wantFiles = []string{"main.go"}
++	if !reflect.DeepEqual(p.GoFiles, wantFiles) {
++		t.Errorf("GoFiles = %v, want %v", p.GoFiles, wantFiles)
++	}
 +}
 diff --git a/src/go/build/testdata/backendtags_openssl/main.go b/src/go/build/testdata/backendtags_openssl/main.go
 new file mode 100644
@@ -394,14 +418,14 @@ index 00000000000000..9c5b0bbc7b99dc
 +const SystemCrypto = true
 +const SystemCryptoInt = 1
 diff --git a/src/internal/goexperiment/flags.go b/src/internal/goexperiment/flags.go
-index ae3cbaf89fa5dd..de79140b2d4780 100644
+index 31b3d0315b64f8..de1dfa6e567a71 100644
 --- a/src/internal/goexperiment/flags.go
 +++ b/src/internal/goexperiment/flags.go
 @@ -60,6 +60,21 @@ type Flags struct {
  	StaticLockRanking bool
  	BoringCrypto      bool
 
-+	// SystemCrypto enables the OpenSSL or CNG crypto experiment depending on
++	// SystemCrypto enables the OpenSSL, CNG or Darwin crypto experiment depending on
 +	// which one is appropriate on the target GOOS.
 +	//
 +	// If SystemCrypto is enabled but no crypto experiment is appropriate on the