Support arch features in bp2build

Bug: 189972518
Test: New soong test
Change-Id: I05d77c8f63ffe6697d8e0300226864658055e116
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index bcf335f..d2abe0f 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -134,6 +134,7 @@
 		"external/libjpeg-turbo":                 Bp2BuildDefaultTrueRecursively,
 		"external/libmpeg2":                      Bp2BuildDefaultTrueRecursively,
 		"external/libpng":                        Bp2BuildDefaultTrueRecursively,
+		"external/libvpx":                        Bp2BuildDefaultTrueRecursively,
 		"external/libyuv":                        Bp2BuildDefaultTrueRecursively,
 		"external/lz4/lib":                       Bp2BuildDefaultTrue,
 		"external/lzma/C":                        Bp2BuildDefaultTrueRecursively,
@@ -471,7 +472,6 @@
 
 		"linker",                 // TODO(b/228316882): cc_binary uses link_crt
 		"versioner",              // TODO(b/228313961):  depends on prebuilt shared library libclang-cpp_host as a shared library, which does not supply expected providers for a shared library
-		"libvpx",                 // TODO(b/240756936): Arm neon variant not supported
 		"art_libartbase_headers", // TODO(b/236268577): Header libraries do not support export_shared_libs_headers
 		"apexer_test",            // Requires aapt2
 		"apexer_test_host_tools",
diff --git a/android/arch.go b/android/arch.go
index 1952b17..9bc9d89 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -19,6 +19,7 @@
 	"fmt"
 	"reflect"
 	"runtime"
+	"sort"
 	"strings"
 
 	"android/soong/bazel"
@@ -2084,13 +2085,22 @@
 	// For each arch type (x86, arm64, etc.)
 	for _, arch := range ArchTypeList() {
 		// Arch properties are sometimes sharded (see createArchPropTypeDesc() ).
-		// Iterate over ever shard and extract a struct with the same type as the
+		// Iterate over every shard and extract a struct with the same type as the
 		// input one that contains the data specific to that arch.
 		propertyStructs := make([]reflect.Value, 0)
+		archFeaturePropertyStructs := make(map[string][]reflect.Value, 0)
 		for _, archProperty := range archProperties {
 			archTypeStruct, ok := getArchTypeStruct(ctx, archProperty, arch)
 			if ok {
 				propertyStructs = append(propertyStructs, archTypeStruct)
+
+				// For each feature this arch supports (arm: neon, x86: ssse3, sse4, ...)
+				for _, feature := range archFeatures[arch] {
+					prefix := "arch." + arch.Name + "." + feature
+					if featureProperties, ok := getChildPropertyStruct(ctx, archTypeStruct, feature, prefix); ok {
+						archFeaturePropertyStructs[feature] = append(archFeaturePropertyStructs[feature], featureProperties)
+					}
+				}
 			}
 			multilibStruct, ok := getMultilibStruct(ctx, archProperty, arch)
 			if ok {
@@ -2098,10 +2108,31 @@
 			}
 		}
 
-		// Create a new instance of the requested property set
-		value := reflect.New(reflect.ValueOf(propertySet).Elem().Type()).Interface()
+		archToProp[arch.Name] = mergeStructs(ctx, propertyStructs, propertySet)
 
-		archToProp[arch.Name] = mergeStructs(ctx, propertyStructs, value)
+		// In soong, if multiple features match the current configuration, they're
+		// all used. In bazel, we have to have unambiguous select() statements, so
+		// we can't have two features that are both active in the same select().
+		// One alternative is to split out each feature into a separate select(),
+		// but then it's difficult to support exclude_srcs, which may need to
+		// exclude things from the regular arch select() statement if a certain
+		// feature is active. Instead, keep the features in the same select
+		// statement as the arches, but emit the power set of all possible
+		// combinations of features, so that bazel can match the most precise one.
+		allFeatures := make([]string, 0, len(archFeaturePropertyStructs))
+		for feature := range archFeaturePropertyStructs {
+			allFeatures = append(allFeatures, feature)
+		}
+		for _, features := range bazel.PowerSetWithoutEmptySet(allFeatures) {
+			sort.Strings(features)
+			propsForCurrentFeatureSet := make([]reflect.Value, 0)
+			propsForCurrentFeatureSet = append(propsForCurrentFeatureSet, propertyStructs...)
+			for _, feature := range features {
+				propsForCurrentFeatureSet = append(propsForCurrentFeatureSet, archFeaturePropertyStructs[feature]...)
+			}
+			archToProp[arch.Name+"-"+strings.Join(features, "-")] =
+				mergeStructs(ctx, propsForCurrentFeatureSet, propertySet)
+		}
 	}
 	axisToProps[bazel.ArchConfigurationAxis] = archToProp
 
diff --git a/bazel/configurability.go b/bazel/configurability.go
index d9b0a12..e1cdd4a 100644
--- a/bazel/configurability.go
+++ b/bazel/configurability.go
@@ -16,6 +16,8 @@
 
 import (
 	"fmt"
+	"math"
+	"sort"
 	"strings"
 )
 
@@ -69,6 +71,71 @@
 	AndroidAndNonApex = "android-non_apex"
 )
 
+func PowerSetWithoutEmptySet[T any](items []T) [][]T {
+	resultSize := int(math.Pow(2, float64(len(items))))
+	powerSet := make([][]T, 0, resultSize-1)
+	for i := 1; i < resultSize; i++ {
+		combination := make([]T, 0)
+		for j := 0; j < len(items); j++ {
+			if (i>>j)%2 == 1 {
+				combination = append(combination, items[j])
+			}
+		}
+		powerSet = append(powerSet, combination)
+	}
+	return powerSet
+}
+
+func createPlatformArchMap() map[string]string {
+	// Copy of archFeatures from android/arch_list.go because the bazel
+	// package can't access the android package
+	archFeatures := map[string][]string{
+		"arm": {
+			"neon",
+		},
+		"arm64": {
+			"dotprod",
+		},
+		"x86": {
+			"ssse3",
+			"sse4",
+			"sse4_1",
+			"sse4_2",
+			"aes_ni",
+			"avx",
+			"avx2",
+			"avx512",
+			"popcnt",
+			"movbe",
+		},
+		"x86_64": {
+			"ssse3",
+			"sse4",
+			"sse4_1",
+			"sse4_2",
+			"aes_ni",
+			"avx",
+			"avx2",
+			"avx512",
+			"popcnt",
+		},
+	}
+	result := make(map[string]string)
+	for arch, allFeatures := range archFeatures {
+		result[arch] = "//build/bazel/platforms/arch:" + arch
+		// Sometimes we want to select on multiple features being active, so
+		// add the power set of all possible features to the map. More details
+		// in android.ModuleBase.GetArchVariantProperties
+		for _, features := range PowerSetWithoutEmptySet(allFeatures) {
+			sort.Strings(features)
+			archFeaturesName := arch + "-" + strings.Join(features, "-")
+			result[archFeaturesName] = "//build/bazel/platforms/arch/variants:" + archFeaturesName
+		}
+	}
+	result[ConditionsDefaultConfigKey] = ConditionsDefaultSelectKey
+	return result
+}
+
 var (
 	// These are the list of OSes and architectures with a Bazel config_setting
 	// and constraint value equivalent. These exist in arch.go, but the android
@@ -77,13 +144,7 @@
 
 	// A map of architectures to the Bazel label of the constraint_value
 	// for the @platforms//cpu:cpu constraint_setting
-	platformArchMap = map[string]string{
-		archArm:                    "//build/bazel/platforms/arch:arm",
-		archArm64:                  "//build/bazel/platforms/arch:arm64",
-		archX86:                    "//build/bazel/platforms/arch:x86",
-		archX86_64:                 "//build/bazel/platforms/arch:x86_64",
-		ConditionsDefaultConfigKey: ConditionsDefaultSelectKey, // The default condition of as arch select map.
-	}
+	platformArchMap = createPlatformArchMap()
 
 	// A map of target operating systems to the Bazel label of the
 	// constraint_value for the @platforms//os:os constraint_setting
diff --git a/bazel/properties.go b/bazel/properties.go
index 13e36b5..d82fa64 100644
--- a/bazel/properties.go
+++ b/bazel/properties.go
@@ -725,7 +725,7 @@
 	case noConfig:
 		return lla.Value
 	case arch, os, osArch, productVariables, osAndInApex:
-		return (lla.ConfigurableValues[axis][config])
+		return lla.ConfigurableValues[axis][config]
 	default:
 		panic(fmt.Errorf("Unrecognized ConfigurationAxis %s", axis))
 	}
diff --git a/bp2build/java_library_conversion_test.go b/bp2build/java_library_conversion_test.go
index 4a4da18..74e2dbd 100644
--- a/bp2build/java_library_conversion_test.go
+++ b/bp2build/java_library_conversion_test.go
@@ -534,3 +534,118 @@
 		ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
 	})
 }
+
+func TestConvertArmNeonVariant(t *testing.T) {
+	t.Helper()
+	RunBp2BuildTestCase(t, func(ctx android.RegistrationContext) {}, Bp2buildTestCase{
+		Description:                "Android Library - simple arch feature",
+		ModuleTypeUnderTest:        "android_library",
+		ModuleTypeUnderTestFactory: java.AndroidLibraryFactory,
+		Blueprint: simpleModuleDoNotConvertBp2build("android_library", "static_lib_dep") + `
+android_library {
+	name: "TestLib",
+	manifest: "manifest/AndroidManifest.xml",
+	srcs: ["lib.java"],
+	arch: {
+		arm: {
+			neon: {
+				srcs: ["arm_neon.java"],
+			},
+		},
+	},
+}
+`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget(
+				"android_library",
+				"TestLib",
+				AttrNameToString{
+					"srcs": `["lib.java"] + select({
+        "//build/bazel/platforms/arch/variants:arm-neon": ["arm_neon.java"],
+        "//conditions:default": [],
+    })`,
+					"manifest":       `"manifest/AndroidManifest.xml"`,
+					"resource_files": `[]`,
+				}),
+		}})
+}
+
+func TestConvertMultipleArchFeatures(t *testing.T) {
+	t.Helper()
+	RunBp2BuildTestCase(t, func(ctx android.RegistrationContext) {}, Bp2buildTestCase{
+		Description:                "Android Library - multiple arch features",
+		ModuleTypeUnderTest:        "android_library",
+		ModuleTypeUnderTestFactory: java.AndroidLibraryFactory,
+		Blueprint: simpleModuleDoNotConvertBp2build("android_library", "static_lib_dep") + `
+android_library {
+	name: "TestLib",
+	manifest: "manifest/AndroidManifest.xml",
+	srcs: ["lib.java"],
+	arch: {
+		x86: {
+			ssse3: {
+				srcs: ["ssse3.java"],
+			},
+			sse4_1: {
+				srcs: ["sse4_1.java"],
+			},
+		},
+	},
+}
+`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget(
+				"android_library",
+				"TestLib",
+				AttrNameToString{
+					"srcs": `["lib.java"] + select({
+        "//build/bazel/platforms/arch/variants:x86-sse4_1": ["sse4_1.java"],
+        "//build/bazel/platforms/arch/variants:x86-sse4_1-ssse3": [
+            "sse4_1.java",
+            "ssse3.java",
+        ],
+        "//build/bazel/platforms/arch/variants:x86-ssse3": ["ssse3.java"],
+        "//conditions:default": [],
+    })`,
+					"manifest":       `"manifest/AndroidManifest.xml"`,
+					"resource_files": `[]`,
+				}),
+		}})
+}
+
+func TestConvertExcludeSrcsArchFeature(t *testing.T) {
+	t.Helper()
+	RunBp2BuildTestCase(t, func(ctx android.RegistrationContext) {}, Bp2buildTestCase{
+		Description:                "Android Library - exclude_srcs with arch feature",
+		ModuleTypeUnderTest:        "android_library",
+		ModuleTypeUnderTestFactory: java.AndroidLibraryFactory,
+		Blueprint: simpleModuleDoNotConvertBp2build("android_library", "static_lib_dep") + `
+android_library {
+	name: "TestLib",
+	manifest: "manifest/AndroidManifest.xml",
+	srcs: ["lib.java"],
+	arch: {
+		arm: {
+			srcs: ["arm_non_neon.java"],
+			neon: {
+				exclude_srcs: ["arm_non_neon.java"],
+			},
+		},
+	},
+}
+`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget(
+				"android_library",
+				"TestLib",
+				AttrNameToString{
+					"srcs": `["lib.java"] + select({
+        "//build/bazel/platforms/arch/variants:arm-neon": [],
+        "//build/bazel/platforms/arch:arm": ["arm_non_neon.java"],
+        "//conditions:default": [],
+    })`,
+					"manifest":       `"manifest/AndroidManifest.xml"`,
+					"resource_files": `[]`,
+				}),
+		}})
+}