Support multilib properties in bp2build
This combines properties among "multilib" and "arch" stanzas in selects
generated by bp2build.
With this fix, libc_gdtoa may be removed from the denylist.
This change also refactors a portion of arch.go, specifically bp2build's
arch mutator, adding a number of comments along the way, to hopefully
make this code clearer for future readers.
Test: mixed_libc.sh
Change-Id: If2beea672957cfb1af6760406ba507181ec38f77
diff --git a/android/arch.go b/android/arch.go
index d7b12bc..1403af4 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -1673,13 +1673,144 @@
return buildTargets, nil
}
+func (m *ModuleBase) getArchPropertySet(propertySet interface{}, archType ArchType) interface{} {
+ archString := archType.Field
+ for i := range m.archProperties {
+ if m.archProperties[i] == nil {
+ // Skip over nil properties
+ continue
+ }
+
+ // Not archProperties are usable; this function looks for properties of a very specific
+ // form, and ignores the rest.
+ for _, archProperty := range m.archProperties[i] {
+ // archPropValue is a property struct, we are looking for the form:
+ // `arch: { arm: { key: value, ... }}`
+ archPropValue := reflect.ValueOf(archProperty).Elem()
+
+ // Unwrap src so that it should looks like a pointer to `arm: { key: value, ... }`
+ src := archPropValue.FieldByName("Arch").Elem()
+
+ // Step into non-nil pointers to structs in the src value.
+ if src.Kind() == reflect.Ptr {
+ if src.IsNil() {
+ continue
+ }
+ src = src.Elem()
+ }
+
+ // Find the requested field (e.g. arm, x86) in the src struct.
+ src = src.FieldByName(archString)
+
+ // We only care about structs.
+ if !src.IsValid() || src.Kind() != reflect.Struct {
+ continue
+ }
+
+ // If the value of the field is a struct then step into the
+ // BlueprintEmbed field. The special "BlueprintEmbed" name is
+ // used by createArchPropTypeDesc to embed the arch properties
+ // in the parent struct, so the src arch prop should be in this
+ // field.
+ //
+ // See createArchPropTypeDesc for more details on how Arch-specific
+ // module properties are processed from the nested props and written
+ // into the module's archProperties.
+ src = src.FieldByName("BlueprintEmbed")
+
+ // Clone the destination prop, since we want a unique prop struct per arch.
+ propertySetClone := reflect.New(reflect.ValueOf(propertySet).Elem().Type()).Interface()
+
+ // Copy the located property struct into the cloned destination property struct.
+ err := proptools.ExtendMatchingProperties([]interface{}{propertySetClone}, src.Interface(), nil, proptools.OrderReplace)
+ if err != nil {
+ // This is fine, it just means the src struct doesn't match the type of propertySet.
+ continue
+ }
+
+ return propertySetClone
+ }
+ }
+ // No property set was found specific to the given arch, so return an empty
+ // property set.
+ return reflect.New(reflect.ValueOf(propertySet).Elem().Type()).Interface()
+}
+
+// getMultilibPropertySet returns a property set struct matching the type of
+// `propertySet`, containing multilib-specific module properties for the given architecture.
+// If no multilib-specific properties exist for the given architecture, returns an empty property
+// set matching `propertySet`'s type.
+func (m *ModuleBase) getMultilibPropertySet(propertySet interface{}, archType ArchType) interface{} {
+ // archType.Multilib is lowercase (for example, lib32) but property struct field is
+ // capitalized, such as Lib32, so use strings.Title to capitalize it.
+ multiLibString := strings.Title(archType.Multilib)
+
+ for i := range m.archProperties {
+ if m.archProperties[i] == nil {
+ // Skip over nil properties
+ continue
+ }
+
+ // Not archProperties are usable; this function looks for properties of a very specific
+ // form, and ignores the rest.
+ for _, archProperties := range m.archProperties[i] {
+ // archPropValue is a property struct, we are looking for the form:
+ // `multilib: { lib32: { key: value, ... }}`
+ archPropValue := reflect.ValueOf(archProperties).Elem()
+
+ // Unwrap src so that it should looks like a pointer to `lib32: { key: value, ... }`
+ src := archPropValue.FieldByName("Multilib").Elem()
+
+ // Step into non-nil pointers to structs in the src value.
+ if src.Kind() == reflect.Ptr {
+ if src.IsNil() {
+ // Ignore nil pointers.
+ continue
+ }
+ src = src.Elem()
+ }
+
+ // Find the requested field (e.g. lib32) in the src struct.
+ src = src.FieldByName(multiLibString)
+
+ // We only care about valid struct pointers.
+ if !src.IsValid() || src.Kind() != reflect.Ptr || src.Elem().Kind() != reflect.Struct {
+ continue
+ }
+
+ // Get the zero value for the requested property set.
+ propertySetClone := reflect.New(reflect.ValueOf(propertySet).Elem().Type()).Interface()
+
+ // Copy the located property struct into the "zero" property set struct.
+ err := proptools.ExtendMatchingProperties([]interface{}{propertySetClone}, src.Interface(), nil, proptools.OrderReplace)
+
+ if err != nil {
+ // This is fine, it just means the src struct doesn't match.
+ continue
+ }
+
+ return propertySetClone
+ }
+ }
+
+ // There were no multilib properties specifically matching the given archtype.
+ // Return zeroed value.
+ return reflect.New(reflect.ValueOf(propertySet).Elem().Type()).Interface()
+}
+
// GetArchProperties returns a map of architectures to the values of the
-// properties of the 'dst' struct that are specific to that architecture.
+// properties of the 'propertySet' struct that are specific to that architecture.
//
// For example, passing a struct { Foo bool, Bar string } will return an
// interface{} that can be type asserted back into the same struct, containing
// the arch specific property value specified by the module if defined.
-func (m *ModuleBase) GetArchProperties(dst interface{}) map[ArchType]interface{} {
+//
+// Arch-specific properties may come from an arch stanza or a multilib stanza; properties
+// in these stanzas are combined.
+// For example: `arch: { x86: { Foo: ["bar"] } }, multilib: { lib32: {` Foo: ["baz"] } }`
+// will result in `Foo: ["bar", "baz"]` being returned for architecture x86, if the given
+// propertyset contains `Foo []string`.
+func (m *ModuleBase) GetArchProperties(propertySet interface{}) map[ArchType]interface{} {
// Return value of the arch types to the prop values for that arch.
archToProp := map[ArchType]interface{}{}
@@ -1688,81 +1819,26 @@
return archToProp
}
- // archProperties has the type of [][]interface{}. Looks complicated, so let's
- // explain this step by step.
- //
- // Loop over the outer index, which determines the property struct that
- // contains a matching set of properties in dst that we're interested in.
- // For example, BaseCompilerProperties or BaseLinkerProperties.
- for i := range m.archProperties {
- if m.archProperties[i] == nil {
- // Skip over nil arch props
- continue
+ // For each arch (x86, arm64, etc.),
+ for _, arch := range ArchTypeList() {
+ // Find arch-specific properties matching that property set type. For example, any
+ // matching properties under `arch { x86 { ... } }`.
+ archPropertySet := m.getArchPropertySet(propertySet, arch)
+
+ // Find multilib-specific properties matching that property set type. For example, any
+ // matching properties under `multilib { lib32 { ... } }` for x86, as x86 is 32-bit.
+ multilibPropertySet := m.getMultilibPropertySet(propertySet, arch)
+
+ // Append the multilibPropertySet to archPropertySet. This combines the
+ // arch and multilib properties into a single property struct.
+ err := proptools.ExtendMatchingProperties([]interface{}{archPropertySet}, multilibPropertySet, nil, proptools.OrderAppend)
+ if err != nil {
+ // archPropertySet and multilibPropertySet must be of the same type, or
+ // something horrible went wrong.
+ panic(err)
}
- // Non-nil arch prop, let's see if the props match up.
- for _, arch := range ArchTypeList() {
- // e.g X86, Arm
- field := arch.Field
-
- // If it's not nil, loop over the inner index, which determines the arch variant
- // of the prop type. In an Android.bp file, this is like looping over:
- //
- // arch: { arm: { key: value, ... }, x86: { key: value, ... } }
- for _, archProperties := range m.archProperties[i] {
- archPropValues := reflect.ValueOf(archProperties).Elem()
-
- // This is the archPropRoot struct. Traverse into the Arch nested struct.
- src := archPropValues.FieldByName("Arch").Elem()
-
- // Step into non-nil pointers to structs in the src value.
- if src.Kind() == reflect.Ptr {
- if src.IsNil() {
- // Ignore nil pointers.
- continue
- }
- src = src.Elem()
- }
-
- // Find the requested field (e.g. x86, x86_64) in the src struct.
- src = src.FieldByName(field)
- if !src.IsValid() {
- continue
- }
-
- // We only care about structs. These are not the droids you are looking for.
- if src.Kind() != reflect.Struct {
- continue
- }
-
- // If the value of the field is a struct then step into the
- // BlueprintEmbed field. The special "BlueprintEmbed" name is
- // used by createArchPropTypeDesc to embed the arch properties
- // in the parent struct, so the src arch prop should be in this
- // field.
- //
- // See createArchPropTypeDesc for more details on how Arch-specific
- // module properties are processed from the nested props and written
- // into the module's archProperties.
- src = src.FieldByName("BlueprintEmbed")
-
- // Clone the destination prop, since we want a unique prop struct per arch.
- dstClone := reflect.New(reflect.ValueOf(dst).Elem().Type()).Interface()
-
- // Copy the located property struct into the cloned destination property struct.
- err := proptools.ExtendMatchingProperties([]interface{}{dstClone}, src.Interface(), nil, proptools.OrderReplace)
- if err != nil {
- // This is fine, it just means the src struct doesn't match.
- continue
- }
-
- // Found the prop for the arch, you have.
- archToProp[arch] = dstClone
-
- // Go to the next prop.
- break
- }
- }
+ archToProp[arch] = archPropertySet
}
return archToProp
}