cmd/dist, internal/platform: test agreement on supported build modes

This synchronizes the supported build modes between cmd/dist and
internal/platform, and adds a test to keep them in synch.

In order to do that, this has several changes to cmd/dist, and one
change to internal/platform.

If the build dashboard is green after this is submitted, we can
probably make the functions identical.

Change-Id: Ia78ce76b193399058fde79e38dd9f23818e566a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/463992
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>

Author: ianlancetaylor

src/cmd/dist/supported_test.go

@@ -0,0 +1,48 @@
+// 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.
+
+package main
+
+import (
+	"internal/platform"
+	"testing"
+)
+
+// TestSupportedBuildModes tests that dist and the main tools agree on
+// which build modes are supported for a given target. We do things
+// this way because the dist tool needs to be buildable directly by
+// the bootstrap compiler, and as such can't import internal packages.
+func TestSupported(t *testing.T) {
+	defer func(a, o string) {
+		goarch = a
+		goos = o
+	}(goarch, goos)
+
+	var modes = []string{
+		// we assume that "exe" and "archive" always work
+		"pie",
+		"c-archive",
+		"c-shared",
+		"shared",
+		"plugin",
+	}
+
+	for _, a := range okgoarch {
+		goarch = a
+		for _, o := range okgoos {
+			if _, ok := cgoEnabled[o+"/"+a]; !ok {
+				continue
+			}
+			goos = o
+			for _, mode := range modes {
+				var dt tester
+				dist := dt.supportedBuildmode(mode)
+				std := platform.BuildModeSupported("gc", mode, o, a)
+				if dist != std {
+					t.Errorf("discrepancy for %s-%s %s: dist says %t, standard library says %t", o, a, mode, dist, std)
+				}
+			}
+		}
+	}
+}

src/cmd/dist/test.go

@@ -1086,21 +1086,14 @@ func (t *tester) out(v string) {
 	fmt.Println("\n" + t.banner + v)
 }
 
+// extLink reports whether the current goos/goarch supports
+// external linking. This should match the test in determineLinkMode
+// in cmd/link/internal/ld/config.go.
 func (t *tester) extLink() bool {
-	pair := goos + "-" + goarch
-	switch pair {
-	case "aix-ppc64",
-		"android-arm", "android-arm64",
-		"darwin-amd64", "darwin-arm64",
-		"dragonfly-amd64",
-		"freebsd-386", "freebsd-amd64", "freebsd-arm", "freebsd-riscv64",
-		"linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-loong64", "linux-ppc64le", "linux-mips64", "linux-mips64le", "linux-mips", "linux-mipsle", "linux-riscv64", "linux-s390x",
-		"netbsd-386", "netbsd-amd64",
-		"openbsd-386", "openbsd-amd64",
-		"windows-386", "windows-amd64":
-		return true
+	if goarch == "ppc64" && goos != "aix" {
+		return false
 	}
-	return false
+	return true
 }
 
 func (t *tester) internalLink() bool {
@@ -1174,7 +1167,7 @@ func (t *tester) supportedBuildmode(mode string) bool {
 		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-arm", "android-arm64", "android-386", "android-amd64",
 			"windows-amd64", "windows-386", "windows-arm64":
 			return true
 		}
@@ -1189,6 +1182,8 @@ func (t *tester) supportedBuildmode(mode string) bool {
 		switch pair {
 		case "linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-s390x", "linux-ppc64le":
 			return true
+		case "android-386", "android-amd64", "android-arm", "android-arm64":
+			return true
 		case "darwin-amd64", "darwin-arm64":
 			return true
 		case "freebsd-amd64":
@@ -1197,13 +1192,15 @@ func (t *tester) supportedBuildmode(mode string) bool {
 		return false
 	case "pie":
 		switch pair {
-		case "aix/ppc64",
+		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":
+		case "darwin-amd64", "darwin-arm64", "ios-amd64", "ios-arm64":
 			return true
-		case "windows-amd64", "windows-386", "windows-arm":
+		case "windows-amd64", "windows-386", "windows-arm", "windows-arm64":
+			return true
+		case "freebsd-amd64":
 			return true
 		}
 		return false