Add Darwin+Arm64 toolchain support

This just sets up the toolchain and allows Darwin+Arm64 to be specified
as a HostCross target. These variants will not be exported to Make, or
be installed on a Soong-only build. A future CL will add support for
universal binaries using these variants.

This config is a bit stranger than the regular 64/32 multilib, as it's
two primary 64-bit configs. And on a Darwin/X86 machine, the Arm64
versions are HostCross (doesn't work on the current machines), while a
Darwin/Arm64 machine, either version works (if Rosetta is installed).

Bug: 203607969
Change-Id: Iacaed77d267773672da027cd74917e33fb1c1e94

android/androidmk.go

@@ -921,6 +921,11 @@ func shouldSkipAndroidMkProcessing(module *ModuleBase) bool {
 		return true
 	}
 
+	// Only expose the primary Darwin target, as Make does not understand Darwin+Arm64
+	if module.Os() == Darwin && module.Target().HostCross {
+		return true
+	}
+
 	return !module.Enabled() ||
 		module.commonProperties.HideFromMake ||
 		// Make does not understand LinuxBionic

android/arch.go

@@ -308,7 +308,7 @@ var (
 	// LinuxMusl is the OS for the Linux kernel plus the musl runtime.
 	LinuxMusl = newOsType("linux_musl", Host, false, X86, X86_64)
 	// Darwin is the OS for MacOS/Darwin host machines.
-	Darwin = newOsType("darwin", Host, false, X86_64)
+	Darwin = newOsType("darwin", Host, false, Arm64, X86_64)
 	// LinuxBionic is the OS for the Linux kernel plus the Bionic libc runtime, but without the
 	// rest of Android.
 	LinuxBionic = newOsType("linux_bionic", Host, false, Arm64, X86_64)
@@ -696,6 +696,11 @@ func archMutator(bpctx blueprint.BottomUpMutatorContext) {
 	for i, m := range modules {
 		addTargetProperties(m, targets[i], multiTargets, i == 0)
 		m.base().setArchProperties(mctx)
+
+		// Install support doesn't understand Darwin+Arm64
+		if os == Darwin && targets[i].HostCross {
+			m.base().commonProperties.SkipInstall = true
+		}
 	}
 }
 

bazel/configurability.go

@@ -39,6 +39,7 @@ const (
 	osArchAndroidArm64      = "android_arm64"
 	osArchAndroidX86        = "android_x86"
 	osArchAndroidX86_64     = "android_x86_64"
+	osArchDarwinArm64       = "darwin_arm64"
 	osArchDarwinX86_64      = "darwin_x86_64"
 	osArchLinuxX86          = "linux_glibc_x86"
 	osArchLinuxX86_64       = "linux_glibc_x86_64"
@@ -96,6 +97,7 @@ var (
 		osArchAndroidArm64:         "//build/bazel/platforms/os_arch:android_arm64",
 		osArchAndroidX86:           "//build/bazel/platforms/os_arch:android_x86",
 		osArchAndroidX86_64:        "//build/bazel/platforms/os_arch:android_x86_64",
+		osArchDarwinArm64:          "//build/bazel/platforms/os_arch:darwin_arm64",
 		osArchDarwinX86_64:         "//build/bazel/platforms/os_arch:darwin_x86_64",
 		osArchLinuxX86:             "//build/bazel/platforms/os_arch:linux_glibc_x86",
 		osArchLinuxX86_64:          "//build/bazel/platforms/os_arch:linux_glibc_x86_64",

cc/config/Android.bp

@@ -24,7 +24,7 @@ bootstrap_go_package {
         "x86_device.go",
         "x86_64_device.go",
 
-        "x86_darwin_host.go",
+        "darwin_host.go",
         "x86_linux_host.go",
         "x86_linux_bionic_host.go",
         "x86_windows_host.go",

cc/config/darwin_host.go

@@ -174,19 +174,43 @@ type toolchainDarwin struct {
 	toolchain64Bit
 }
 
-func (t *toolchainDarwin) Name() string {
+type toolchainDarwinX86 struct {
+	toolchainDarwin
+}
+
+type toolchainDarwinArm struct {
+	toolchainDarwin
+}
+
+func (t *toolchainDarwinArm) Name() string {
+	return "arm64"
+}
+
+func (t *toolchainDarwinX86) Name() string {
 	return "x86_64"
 }
 
-func (t *toolchainDarwin) GccRoot() string {
+func (t *toolchainDarwinArm) GccRoot() string {
+	panic("unimplemented")
+}
+
+func (t *toolchainDarwinArm) GccTriple() string {
+	panic("unimplemented")
+}
+
+func (t *toolchainDarwinArm) GccVersion() string {
+	panic("unimplemented")
+}
+
+func (t *toolchainDarwinX86) GccRoot() string {
 	return "${config.DarwinGccRoot}"
 }
 
-func (t *toolchainDarwin) GccTriple() string {
+func (t *toolchainDarwinX86) GccTriple() string {
 	return "${config.DarwinGccTriple}"
 }
 
-func (t *toolchainDarwin) GccVersion() string {
+func (t *toolchainDarwinX86) GccVersion() string {
 	return darwinGccVersion
 }
 
@@ -194,7 +218,11 @@ func (t *toolchainDarwin) IncludeFlags() string {
 	return ""
 }
 
-func (t *toolchainDarwin) ClangTriple() string {
+func (t *toolchainDarwinArm) ClangTriple() string {
+	return "aarch64-apple-darwin"
+}
+
+func (t *toolchainDarwinX86) ClangTriple() string {
 	return "x86_64-apple-darwin"
 }
 
@@ -230,12 +258,18 @@ func (t *toolchainDarwin) ToolPath() string {
 	return "${config.MacToolPath}"
 }
 
-var toolchainDarwinSingleton Toolchain = &toolchainDarwin{}
+var toolchainDarwinArmSingleton Toolchain = &toolchainDarwinArm{}
+var toolchainDarwinX86Singleton Toolchain = &toolchainDarwinX86{}
 
-func darwinToolchainFactory(arch android.Arch) Toolchain {
-	return toolchainDarwinSingleton
+func darwinArmToolchainFactory(arch android.Arch) Toolchain {
+	return toolchainDarwinArmSingleton
+}
+
+func darwinX86ToolchainFactory(arch android.Arch) Toolchain {
+	return toolchainDarwinX86Singleton
 }
 
 func init() {
-	registerToolchainFactory(android.Darwin, android.X86_64, darwinToolchainFactory)
+	registerToolchainFactory(android.Darwin, android.Arm64, darwinArmToolchainFactory)
+	registerToolchainFactory(android.Darwin, android.X86_64, darwinX86ToolchainFactory)
 }

rust/config/Android.bp

@@ -16,7 +16,7 @@ bootstrap_go_package {
         "lints.go",
         "toolchain.go",
         "allowed_list.go",
-        "x86_darwin_host.go",
+        "darwin_host.go",
         "x86_linux_bionic_host.go",
         "x86_linux_host.go",
         "x86_device.go",

rust/config/darwin_host.go

@@ -25,41 +25,64 @@ var (
 	DarwinRustLinkFlags = []string{
 		"-B${cc_config.MacToolPath}",
 	}
+	darwinArm64Rustflags = []string{}
+	darwinArm64Linkflags = []string{}
 	darwinX8664Rustflags = []string{}
 	darwinX8664Linkflags = []string{}
 )
 
 func init() {
+	registerToolchainFactory(android.Darwin, android.Arm64, darwinArm64ToolchainFactory)
 	registerToolchainFactory(android.Darwin, android.X86_64, darwinX8664ToolchainFactory)
+
 	pctx.StaticVariable("DarwinToolchainRustFlags", strings.Join(DarwinRustFlags, " "))
 	pctx.StaticVariable("DarwinToolchainLinkFlags", strings.Join(DarwinRustLinkFlags, " "))
+
+	pctx.StaticVariable("DarwinToolchainArm64RustFlags", strings.Join(darwinArm64Rustflags, " "))
+	pctx.StaticVariable("DarwinToolchainArm64LinkFlags", strings.Join(darwinArm64Linkflags, " "))
 	pctx.StaticVariable("DarwinToolchainX8664RustFlags", strings.Join(darwinX8664Rustflags, " "))
 	pctx.StaticVariable("DarwinToolchainX8664LinkFlags", strings.Join(darwinX8664Linkflags, " "))
 
 }
 
 type toolchainDarwin struct {
+	toolchain64Bit
 	toolchainRustFlags string
 	toolchainLinkFlags string
 }
 
-type toolchainDarwinX8664 struct {
-	toolchain64Bit
+type toolchainDarwinArm64 struct {
 	toolchainDarwin
 }
 
+type toolchainDarwinX8664 struct {
+	toolchainDarwin
+}
+
+func (toolchainDarwinArm64) Supported() bool {
+	return true
+}
+
 func (toolchainDarwinX8664) Supported() bool {
 	return true
 }
 
-func (toolchainDarwinX8664) Bionic() bool {
+func (toolchainDarwin) Bionic() bool {
 	return false
 }
 
+func (t *toolchainDarwinArm64) Name() string {
+	return "arm64"
+}
+
 func (t *toolchainDarwinX8664) Name() string {
 	return "x86_64"
 }
 
+func (t *toolchainDarwinArm64) RustTriple() string {
+	return "aarch64-apple-darwin"
+}
+
 func (t *toolchainDarwinX8664) RustTriple() string {
 	return "x86_64-apple-darwin"
 }
@@ -76,6 +99,15 @@ func (t *toolchainDarwin) ProcMacroSuffix() string {
 	return ".dylib"
 }
 
+func (t *toolchainDarwinArm64) ToolchainLinkFlags() string {
+	// Prepend the lld flags from cc_config so we stay in sync with cc
+	return "${cc_config.DarwinLldflags} ${config.DarwinToolchainLinkFlags} ${config.DarwinToolchainArm64LinkFlags}"
+}
+
+func (t *toolchainDarwinArm64) ToolchainRustFlags() string {
+	return "${config.DarwinToolchainRustFlags} ${config.DarwinToolchainArm64RustFlags}"
+}
+
 func (t *toolchainDarwinX8664) ToolchainLinkFlags() string {
 	// Prepend the lld flags from cc_config so we stay in sync with cc
 	return "${cc_config.DarwinLldflags} ${config.DarwinToolchainLinkFlags} ${config.DarwinToolchainX8664LinkFlags}"
@@ -85,8 +117,13 @@ func (t *toolchainDarwinX8664) ToolchainRustFlags() string {
 	return "${config.DarwinToolchainRustFlags} ${config.DarwinToolchainX8664RustFlags}"
 }
 
+func darwinArm64ToolchainFactory(arch android.Arch) Toolchain {
+	return toolchainDarwinArm64Singleton
+}
+
 func darwinX8664ToolchainFactory(arch android.Arch) Toolchain {
 	return toolchainDarwinX8664Singleton
 }
 
+var toolchainDarwinArm64Singleton Toolchain = &toolchainDarwinArm64{}
 var toolchainDarwinX8664Singleton Toolchain = &toolchainDarwinX8664{}