diff --git a/android/bazel.go b/android/bazel.go
index f4686a0..9efc033 100644
--- a/android/bazel.go
+++ b/android/bazel.go
@@ -15,7 +15,6 @@
 package android
 
 import (
-	"android/soong/bazel"
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
@@ -25,11 +24,28 @@
 	"github.com/google/blueprint/proptools"
 )
 
+type bazelModuleProperties struct {
+	// The label of the Bazel target replacing this Soong module. When run in conversion mode, this
+	// will import the handcrafted build target into the autogenerated file. Note: this may result in
+	// a conflict due to duplicate targets if bp2build_available is also set.
+	Label *string
+
+	// If true, bp2build will generate the converted Bazel target for this module. Note: this may
+	// cause a conflict due to the duplicate targets if label is also set.
+	//
+	// This is a bool pointer to support tristates: true, false, not set.
+	//
+	// To opt-in a module, set bazel_module: { bp2build_available: true }
+	// To opt-out a module, set bazel_module: { bp2build_available: false }
+	// To defer the default setting for the directory, do not set the value.
+	Bp2build_available *bool
+}
+
 // Properties contains common module properties for Bazel migration purposes.
 type properties struct {
 	// In USE_BAZEL_ANALYSIS=1 mode, this represents the Bazel target replacing
 	// this Soong module.
-	Bazel_module bazel.BazelModuleProperties
+	Bazel_module bazelModuleProperties
 }
 
 // namespacedVariableProperties is a map from a string representing a Soong
diff --git a/android/config.go b/android/config.go
index 6f05565..5ee28e7 100644
--- a/android/config.go
+++ b/android/config.go
@@ -155,9 +155,10 @@
 	fs         pathtools.FileSystem
 	mockBpList string
 
-	runningAsBp2Build        bool
-	bp2buildPackageConfig    Bp2BuildConfig
-	bp2buildModuleTypeConfig map[string]bool
+	runningAsBp2Build              bool
+	bp2buildPackageConfig          Bp2BuildConfig
+	bp2buildModuleTypeConfig       map[string]bool
+	Bp2buildSoongConfigDefinitions soongconfig.Bp2BuildSoongConfigDefinitions
 
 	// If testAllowNonExistentPaths is true then PathForSource and PathForModuleSrc won't error
 	// in tests when a path doesn't exist.
diff --git a/android/soong_config_modules.go b/android/soong_config_modules.go
index dcf2223..91bbce6 100644
--- a/android/soong_config_modules.go
+++ b/android/soong_config_modules.go
@@ -380,6 +380,9 @@
 		}
 
 		mtDef, errs := soongconfig.Parse(r, from)
+		if ctx.Config().runningAsBp2Build {
+			ctx.Config().Bp2buildSoongConfigDefinitions.AddVars(*mtDef)
+		}
 
 		if len(errs) > 0 {
 			reportErrors(ctx, from, errs...)
@@ -415,14 +418,13 @@
 	if !conditionalFactoryProps.IsValid() {
 		return factory
 	}
-	useBp2buildHook := bp2build && proptools.BoolDefault(moduleType.Bp2buildAvailable, false)
 
 	return func() (blueprint.Module, []interface{}) {
 		module, props := factory()
 		conditionalProps := proptools.CloneEmptyProperties(conditionalFactoryProps)
 		props = append(props, conditionalProps.Interface())
 
-		if useBp2buildHook {
+		if bp2build {
 			// The loadhook is different for bp2build, since we don't want to set a specific
 			// set of property values based on a vendor var -- we want __all of them__ to
 			// generate select statements, so we put the entire soong_config_variables
diff --git a/android/soongconfig/modules.go b/android/soongconfig/modules.go
index 1af89ba..3a93f47 100644
--- a/android/soongconfig/modules.go
+++ b/android/soongconfig/modules.go
@@ -15,7 +15,6 @@
 package soongconfig
 
 import (
-	"android/soong/bazel"
 	"fmt"
 	"io"
 	"reflect"
@@ -121,8 +120,6 @@
 
 	// the list of properties that this module type will extend.
 	Properties []string
-
-	Bazel_module bazel.BazelModuleProperties
 }
 
 func processModuleTypeDef(v *SoongConfigDefinition, def *parser.Module) (errs []error) {
@@ -233,6 +230,96 @@
 	variables map[string]soongConfigVariable
 }
 
+// Bp2BuildSoongConfigDefinition keeps a global record of all soong config
+// string vars, bool vars and value vars created by every
+// soong_config_module_type in this build.
+type Bp2BuildSoongConfigDefinitions struct {
+	StringVars map[string]map[string]bool
+	BoolVars   map[string]bool
+	ValueVars  map[string]bool
+}
+
+// SoongConfigVariablesForBp2build extracts information from a
+// SoongConfigDefinition that bp2build needs to generate constraint settings and
+// values for, in order to migrate soong_config_module_type usages to Bazel.
+func (defs *Bp2BuildSoongConfigDefinitions) AddVars(mtDef SoongConfigDefinition) {
+	if defs.StringVars == nil {
+		defs.StringVars = make(map[string]map[string]bool)
+	}
+	if defs.BoolVars == nil {
+		defs.BoolVars = make(map[string]bool)
+	}
+	if defs.ValueVars == nil {
+		defs.ValueVars = make(map[string]bool)
+	}
+	for _, moduleType := range mtDef.ModuleTypes {
+		for _, v := range moduleType.Variables {
+			key := strings.Join([]string{moduleType.ConfigNamespace, v.variableProperty()}, "__")
+			if strVar, ok := v.(*stringVariable); ok {
+				if _, ok := defs.StringVars[key]; !ok {
+					defs.StringVars[key] = make(map[string]bool, 0)
+				}
+				for _, value := range strVar.values {
+					defs.StringVars[key][value] = true
+				}
+			} else if _, ok := v.(*boolVariable); ok {
+				defs.BoolVars[key] = true
+			} else if _, ok := v.(*valueVariable); ok {
+				defs.ValueVars[key] = true
+			} else {
+				panic(fmt.Errorf("Unsupported variable type: %+v", v))
+			}
+		}
+	}
+}
+
+// This is a copy of the one available in soong/android/util.go, but depending
+// on the android package causes a cyclic dependency. A refactoring here is to
+// extract common utils out from android/utils.go for other packages like this.
+func sortedStringKeys(m interface{}) []string {
+	v := reflect.ValueOf(m)
+	if v.Kind() != reflect.Map {
+		panic(fmt.Sprintf("%#v is not a map", m))
+	}
+	keys := v.MapKeys()
+	s := make([]string, 0, len(keys))
+	for _, key := range keys {
+		s = append(s, key.String())
+	}
+	sort.Strings(s)
+	return s
+}
+
+// String emits the Soong config variable definitions as Starlark dictionaries.
+func (defs Bp2BuildSoongConfigDefinitions) String() string {
+	ret := ""
+	ret += "soong_config_bool_variables = {\n"
+	for _, boolVar := range sortedStringKeys(defs.BoolVars) {
+		ret += fmt.Sprintf("    \"%s\": True,\n", boolVar)
+	}
+	ret += "}\n"
+	ret += "\n"
+
+	ret += "soong_config_value_variables = {\n"
+	for _, valueVar := range sortedStringKeys(defs.ValueVars) {
+		ret += fmt.Sprintf("    \"%s\": True,\n", valueVar)
+	}
+	ret += "}\n"
+	ret += "\n"
+
+	ret += "soong_config_string_variables = {\n"
+	for _, stringVar := range sortedStringKeys(defs.StringVars) {
+		ret += fmt.Sprintf("    \"%s\": [\n", stringVar)
+		for _, choice := range sortedStringKeys(defs.StringVars[stringVar]) {
+			ret += fmt.Sprintf("        \"%s\",\n", choice)
+		}
+		ret += fmt.Sprintf("    ],\n")
+	}
+	ret += "}"
+
+	return ret
+}
+
 // CreateProperties returns a reflect.Value of a newly constructed type that contains the desired
 // property layout for the Soong config variables, with each possible value an interface{} that
 // contains a nil pointer to another newly constructed type that contains the affectable properties.
@@ -436,7 +523,6 @@
 
 	affectableProperties []string
 	variableNames        []string
-	Bp2buildAvailable    *bool
 }
 
 func newModuleType(props *ModuleTypeProperties) (*ModuleType, []error) {
@@ -445,7 +531,6 @@
 		ConfigNamespace:      props.Config_namespace,
 		BaseModuleType:       props.Module_type,
 		variableNames:        props.Variables,
-		Bp2buildAvailable:    props.Bazel_module.Bp2build_available,
 	}
 
 	for _, name := range props.Bool_variables {
diff --git a/android/soongconfig/modules_test.go b/android/soongconfig/modules_test.go
index 48cdfe7..b14f8b4 100644
--- a/android/soongconfig/modules_test.go
+++ b/android/soongconfig/modules_test.go
@@ -364,3 +364,117 @@
 		}
 	}
 }
+
+func Test_Bp2BuildSoongConfigDefinitions(t *testing.T) {
+	testCases := []struct {
+		defs     Bp2BuildSoongConfigDefinitions
+		expected string
+	}{
+		{
+			defs: Bp2BuildSoongConfigDefinitions{},
+			expected: `soong_config_bool_variables = {
+}
+
+soong_config_value_variables = {
+}
+
+soong_config_string_variables = {
+}`}, {
+			defs: Bp2BuildSoongConfigDefinitions{
+				BoolVars: map[string]bool{
+					"bool_var": true,
+				},
+			},
+			expected: `soong_config_bool_variables = {
+    "bool_var": True,
+}
+
+soong_config_value_variables = {
+}
+
+soong_config_string_variables = {
+}`}, {
+			defs: Bp2BuildSoongConfigDefinitions{
+				ValueVars: map[string]bool{
+					"value_var": true,
+				},
+			},
+			expected: `soong_config_bool_variables = {
+}
+
+soong_config_value_variables = {
+    "value_var": True,
+}
+
+soong_config_string_variables = {
+}`}, {
+			defs: Bp2BuildSoongConfigDefinitions{
+				StringVars: map[string]map[string]bool{
+					"string_var": map[string]bool{
+						"choice1": true,
+						"choice2": true,
+						"choice3": true,
+					},
+				},
+			},
+			expected: `soong_config_bool_variables = {
+}
+
+soong_config_value_variables = {
+}
+
+soong_config_string_variables = {
+    "string_var": [
+        "choice1",
+        "choice2",
+        "choice3",
+    ],
+}`}, {
+			defs: Bp2BuildSoongConfigDefinitions{
+				BoolVars: map[string]bool{
+					"bool_var_one": true,
+				},
+				ValueVars: map[string]bool{
+					"value_var_one": true,
+					"value_var_two": true,
+				},
+				StringVars: map[string]map[string]bool{
+					"string_var_one": map[string]bool{
+						"choice1": true,
+						"choice2": true,
+						"choice3": true,
+					},
+					"string_var_two": map[string]bool{
+						"foo": true,
+						"bar": true,
+					},
+				},
+			},
+			expected: `soong_config_bool_variables = {
+    "bool_var_one": True,
+}
+
+soong_config_value_variables = {
+    "value_var_one": True,
+    "value_var_two": True,
+}
+
+soong_config_string_variables = {
+    "string_var_one": [
+        "choice1",
+        "choice2",
+        "choice3",
+    ],
+    "string_var_two": [
+        "bar",
+        "foo",
+    ],
+}`},
+	}
+	for _, test := range testCases {
+		actual := test.defs.String()
+		if actual != test.expected {
+			t.Errorf("Expected:\n%s\nbut got:\n%s", test.expected, actual)
+		}
+	}
+}