Disable cc_benchmark for Darwin hosts

The google-benchmark library is disabled on Darwin, so we cannot create
host benchmarks. Instead of having every user specify this, put the
logic in Soong. Then if we decide to support it later, it's an easier
switch.

Test: build.ninja identical before/after on Linux
Test: Ignores failing cc_benchmark_host on Darwin
Change-Id: I61f3a571fd160d8e479a512992bc68601f1c9b28

android/arch.go

@@ -267,12 +267,12 @@ func ArchMutator(mctx BottomUpMutatorContext) {
 		return
 	}
 
-	osClasses := module.base().OsClassSupported()
+	if !module.base().ArchSpecific() {
-
-	if len(osClasses) == 0 {
 		return
 	}
 
+	osClasses := module.base().OsClassSupported()
+
 	var moduleTargets []Target
 	primaryModules := make(map[int]bool)
 

android/module.go

@@ -152,6 +152,7 @@ type commonProperties struct {
 
 	// Set by InitAndroidModule
 	HostOrDeviceSupported HostOrDeviceSupported `blueprint:"mutated"`
+	ArchSpecific          bool                  `blueprint:"mutated"`
 }
 
 type hostAndDeviceProperties struct {
@@ -176,6 +177,7 @@ const (
 	DeviceSupported
 	HostAndDeviceSupported
 	HostAndDeviceDefault
+	NeitherHostNorDeviceSupported
 )
 
 func InitAndroidModule(m Module,
@@ -197,6 +199,7 @@ func InitAndroidArchModule(m Module, hod HostOrDeviceSupported, defaultMultilib
 	base := m.base()
 	base.commonProperties.HostOrDeviceSupported = hod
 	base.commonProperties.Default_multilib = string(defaultMultilib)
+	base.commonProperties.ArchSpecific = true
 
 	switch hod {
 	case HostAndDeviceSupported:
@@ -305,6 +308,10 @@ func (a *ModuleBase) Arch() Arch {
 	return a.Target().Arch
 }
 
+func (a *ModuleBase) ArchSpecific() bool {
+	return a.commonProperties.ArchSpecific
+}
+
 func (a *ModuleBase) OsClassSupported() []OsClass {
 	switch a.commonProperties.HostOrDeviceSupported {
 	case HostSupported:

cc/test.go

@@ -16,6 +16,7 @@ package cc
 
 import (
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/google/blueprint"
@@ -301,6 +302,16 @@ func (benchmark *benchmarkDecorator) install(ctx ModuleContext, file android.Pat
 }
 
 func NewBenchmark(hod android.HostOrDeviceSupported) *Module {
+	// Benchmarks aren't supported on Darwin
+	if runtime.GOOS == "darwin" {
+		switch hod {
+		case android.HostAndDeviceSupported:
+			hod = android.DeviceSupported
+		case android.HostSupported:
+			hod = android.NeitherHostNorDeviceSupported
+		}
+	}
+
 	module, binary := NewBinary(hod)
 	module.multilib = android.MultilibBoth
 	binary.baseInstaller = NewTestInstaller()