cmd/dist: use a copy of platform.BuildModeSupported

The dist tool already includes a similar duplicate of BuildModeSupported.
Replace it with an exact copy, to make it easier to maintain going forward.

Change-Id: Id14a6c5a48f92d843e02218d87cc62c6b001923b
Reviewed-on: https://go-review.googlesource.com/c/go/+/467495
Reviewed-by: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>

Author: ianlancetaylor

src/cmd/dist/test.go

@@ -1136,79 +1136,14 @@ func (t *tester) internalLinkPIE() bool {
 
 // supportedBuildMode reports whether the given build mode is supported.
 func (t *tester) supportedBuildmode(mode string) bool {
-	pair := goos + "-" + goarch
 	switch mode {
-	case "c-archive":
-		if !t.extLink() {
-			return false
-		}
-		switch goos {
-		case "aix", "darwin", "ios", "windows":
-			return true
-		case "linux":
-			switch goarch {
-			case "386", "amd64", "arm", "armbe", "arm64", "arm64be", "ppc64", "ppc64le", "riscv64", "s390x":
-				return true
-			default:
-				// Other targets do not support -shared,
-				// per ParseFlags in
-				// cmd/compile/internal/base/flag.go.
-				// For c-archive the Go tool passes -shared,
-				// so that the result is suitable for inclusion
-				// in a PIE or shared library.
-				return false
-			}
-		case "freebsd":
-			return goarch == "amd64"
-		}
-		return false
-	case "c-shared":
-		switch pair {
-		case "linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-ppc64le", "linux-riscv64", "linux-s390x",
-			"darwin-amd64", "darwin-arm64",
-			"freebsd-amd64",
-			"android-arm", "android-arm64", "android-386", "android-amd64",
-			"windows-amd64", "windows-386", "windows-arm64":
-			return true
-		}
-		return false
-	case "shared":
-		switch pair {
-		case "linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-ppc64le", "linux-s390x":
-			return true
-		}
-		return false
-	case "plugin":
-		switch pair {
-		case "linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-s390x", "linux-ppc64le":
-			return true
-		case "android-386", "android-amd64":
-			return true
-		case "darwin-amd64", "darwin-arm64":
-			return true
-		case "freebsd-amd64":
-			return true
-		}
-		return false
-	case "pie":
-		switch pair {
-		case "aix-ppc64",
-			"linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-ppc64le", "linux-riscv64", "linux-s390x",
-			"android-amd64", "android-arm", "android-arm64", "android-386":
-			return true
-		case "darwin-amd64", "darwin-arm64", "ios-amd64", "ios-arm64":
-			return true
-		case "windows-amd64", "windows-386", "windows-arm", "windows-arm64":
-			return true
-		case "freebsd-amd64":
-			return true
-		}
-		return false
-
+	case "c-archive", "c-shared", "shared", "plugin", "pie":
 	default:
 		fatalf("internal error: unknown buildmode %s", mode)
 		return false
 	}
+
+	return buildModeSupported("gc", mode, goos, goarch)
 }
 
 func (t *tester) registerCgoTests() {
@@ -1737,6 +1672,96 @@ func raceDetectorSupported(goos, goarch string) bool {
 	}
 }
 
+// buildModeSupports is a copy of the function
+// internal/platform.BuildModeSupported, which can't be used here
+// because cmd/dist can not import internal packages during bootstrap.
+func buildModeSupported(compiler, buildmode, goos, goarch string) bool {
+	if compiler == "gccgo" {
+		return true
+	}
+
+	platform := goos + "/" + goarch
+
+	switch buildmode {
+	case "archive":
+		return true
+
+	case "c-archive":
+		switch goos {
+		case "aix", "darwin", "ios", "windows":
+			return true
+		case "linux":
+			switch goarch {
+			case "386", "amd64", "arm", "armbe", "arm64", "arm64be", "ppc64le", "riscv64", "s390x":
+				// linux/ppc64 not supported because it does
+				// not support external linking mode yet.
+				return true
+			default:
+				// Other targets do not support -shared,
+				// per ParseFlags in
+				// cmd/compile/internal/base/flag.go.
+				// For c-archive the Go tool passes -shared,
+				// so that the result is suitable for inclusion
+				// in a PIE or shared library.
+				return false
+			}
+		case "freebsd":
+			return goarch == "amd64"
+		}
+		return false
+
+	case "c-shared":
+		switch platform {
+		case "linux/amd64", "linux/arm", "linux/arm64", "linux/386", "linux/ppc64le", "linux/riscv64", "linux/s390x",
+			"android/amd64", "android/arm", "android/arm64", "android/386",
+			"freebsd/amd64",
+			"darwin/amd64", "darwin/arm64",
+			"windows/amd64", "windows/386", "windows/arm64":
+			return true
+		}
+		return false
+
+	case "default":
+		return true
+
+	case "exe":
+		return true
+
+	case "pie":
+		switch platform {
+		case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/riscv64", "linux/s390x",
+			"android/amd64", "android/arm", "android/arm64", "android/386",
+			"freebsd/amd64",
+			"darwin/amd64", "darwin/arm64",
+			"ios/amd64", "ios/arm64",
+			"aix/ppc64",
+			"windows/386", "windows/amd64", "windows/arm", "windows/arm64":
+			return true
+		}
+		return false
+
+	case "shared":
+		switch platform {
+		case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x":
+			return true
+		}
+		return false
+
+	case "plugin":
+		switch platform {
+		case "linux/amd64", "linux/arm", "linux/arm64", "linux/386", "linux/s390x", "linux/ppc64le",
+			"android/amd64", "android/386",
+			"darwin/amd64", "darwin/arm64",
+			"freebsd/amd64":
+			return true
+		}
+		return false
+
+	default:
+		return false
+	}
+}
+
 // isUnsupportedVMASize reports whether the failure is caused by an unsupported
 // VMA for the race detector (for example, running the race detector on an
 // arm64 machine configured with 39-bit VMA)

src/internal/platform/supported.go

@@ -88,6 +88,7 @@ func MustLinkExternal(goos, goarch string) bool {
 
 // BuildModeSupported reports whether goos/goarch supports the given build mode
 // using the given compiler.
+// There is a copy of this function in cmd/dist/test.go.
 func BuildModeSupported(compiler, buildmode, goos, goarch string) bool {
 	if compiler == "gccgo" {
 		return true