Remove unneeded swift_name attributes from Objective-C headers

Partial fix for
KT-81447 Native: Objective-C: Excessive 'swift_name' attributes being generated

Removes swift_name attribute from declarations that would already have that swift name.
Initially focusing on properties and and simple methods that have no parameters.

The excessive use of swift_attributes creates large headers, and even larger pcm files
generated from those headers.

Author: dmaclach

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportCodeSpec.kt

@@ -90,7 +90,9 @@ internal fun ObjCExportedInterface.createCodeSpec(symbolTable: SymbolTable): Obj
 
             if (descriptor.kind == ClassKind.ENUM_CLASS) {
                 descriptor.enumEntries.mapTo(methods) {
-                    ObjCGetterForKotlinEnumEntry(symbolTable.descriptorExtension.referenceEnumEntry(it), namer.getEnumEntrySelector(it))
+                    ObjCGetterForKotlinEnumEntry(
+                            symbolTable.descriptorExtension.referenceEnumEntry(it),
+                            namer.getEnumEntryName(it).objCName)
                 }
 
                 descriptor.getEnumValuesFunctionDescriptor()?.let {
@@ -133,7 +135,7 @@ internal fun <S : IrFunctionSymbol> createObjCMethodSpecBaseMethod(
 ): ObjCMethodSpec.BaseMethod<S> {
     require(mapper.isBaseMethod(descriptor))
 
-    val selector = namer.getSelector(descriptor)
+    val selector = namer.getFunctionName(descriptor).objCName
     val bridge = mapper.bridgeMethod(descriptor)
 
     return ObjCMethodSpec.BaseMethod(symbol, bridge, selector)

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/analysisApiUtils/errors.kt

@@ -51,7 +51,7 @@ internal val KtObjCExportSession.errorInterface
                 returnType = ObjCInstanceType,
                 selectors = listOf("init"),
                 parameters = emptyList(),
-                attributes = listOf("swift_name(\"init()\")", "objc_designated_initializer")
+                attributes = listOf("objc_designated_initializer")
             ),
             ObjCMethod(
                 comment = null,

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/analysisApiUtils/getDefaultSuperClassOrProtocolName.kt

@@ -8,7 +8,7 @@ import org.jetbrains.kotlin.objcexport.getObjCKotlinStdlibClassOrProtocolName
  * Some entities like top level functions are wrapped into classes with Base super class.
  *
  * @interface FooKt : Base
- * + (NSString *)myTopLevelFunction __attribute__((swift_name("myTopLevelFunction()")));
+ * + (NSString *)myTopLevelFunction;
  * @end
  */
 internal fun KtObjCExportSession.getDefaultSuperClassOrProtocolName(): ObjCExportClassOrProtocolName {

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/buildCompanionProperty.kt

@@ -37,6 +37,6 @@ internal fun ObjCExportContext.buildCompanionProperty(classSymbol: KaClassSymbol
         }),
         propertyAttributes = listOf("class", "readonly"),
         getterName = propertyName,
-        declarationAttributes = listOf(swiftNameAttribute(propertyName))
+        declarationAttributes = emptyList(),
     )
 }

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/buildThrowableAsErrorMethod.kt

@@ -14,7 +14,7 @@ internal fun buildThrowableAsErrorMethod(): ObjCMethod {
         returnType = ObjCClassType("NSError"),
         selectors = listOf("asError"),
         parameters = emptyList(),
-        attributes = listOf(swiftNameAttribute("asError()")),
+        attributes = emptyList(),
         origin = null
     )
 }

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/mangling/ObjCMethodMangler.kt

@@ -18,37 +18,35 @@ import org.jetbrains.kotlin.backend.konan.objcexport.swiftNameAttribute
  */
 internal class ObjCMethodMangler {
 
-    private val mangledMethods = mutableMapOf<String, ObjCMemberDetails>()
+    private val mangledMethods = mutableSetOf<String>()
 
     fun mangle(member: ObjCExportStub, containingStub: ObjCExportStub): ObjCExportStub {
-        if (!member.isSwiftNameMethod()) return member
-        require(member is ObjCMethod)
-        if (!contains(member)) {
-            cacheMember(member)
-            return member
-        } else {
-            val key = getMemberKey(member)
-            val attribute = mangledMethods[key] ?: error("No cached item for $member")
-            val mangledAttribute = attribute.mangleAttribute()
-            val cloned = member.copy(
-                mangledSelectors = buildMangledSelectors(mangledAttribute),
-                mangledParameters = buildMangledParameters(mangledAttribute),
-                swiftNameAttribute = buildMangledSwiftNameMethodAttribute(mangledAttribute, containingStub),
-                containingStubName = containingStub.name
-            )
-            mangledMethods[key] = mangledAttribute
-            return cloned
+        if (member is ObjCMethod) {
+            var cloned: ObjCMethod = member
+            while (true) {
+                val key = getMemberKey(cloned)
+                if (!mangledMethods.contains(key)) {
+                    mangledMethods.add(key)
+                    return cloned
+                }
+                val newSelectors = cloned.selectors.toMutableList()
+                val lastIndex = newSelectors.lastIndex
+                var lastSelector = newSelectors[lastIndex]
+                if (lastSelector.endsWith(":")) {
+                    // - (void)foo:; -> -(void)foo_:;
+                    // - (void)foo:bar:; -> -(void)foo:bar_:;
+                    lastSelector = lastSelector.dropLast(1) + "_:"
+                } else {
+                    // - (void)foo; -> -(void)foo_;
+                    lastSelector += "_"
+                }
+                newSelectors[lastIndex] = lastSelector
+                cloned = member.copy(
+                    mangledSelectors = newSelectors,
+                    containingStubName = containingStub.name
+                )
+            }
         }
-    }
-
-    private fun contains(member: ObjCExportStub): Boolean {
-        if (!member.isSwiftNameMethod()) return false
-        return mangledMethods[getMemberKey(member as ObjCMethod)] != null
-    }
-
-    private fun cacheMember(member: ObjCMethod) {
-        val memberKey = getMemberKey(member)
-        val swiftNameAttr = getSwiftNameAttribute(member)
-        mangledMethods[memberKey] = parseSwiftMethodNameAttribute(swiftNameAttr, member.returnType == ObjCInstanceType, member.parameters)
+        return member
     }
 }

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/mangling/ObjCPropertyMangler.kt

@@ -14,39 +14,33 @@ class ObjCPropertyMangler {
     private val mangledProperties = hashSetOf<String>()
 
     fun mangle(member: ObjCExportStub, containingStub: ObjCExportStub): ObjCExportStub {
-        return if (member.isSwiftNameProperty()) {
-            val key = getSwiftNameAttribute(member as ObjCProperty)
-            if (mangledProperties.contains(key)) {
+        return if (member is ObjCProperty) {
+            val name = member.name
+            if (mangledProperties.contains(name)) {
                 val copy = if (containingStub.isExtensionFacade) {
-                    val attr = parseSwiftPropertyNameAttribute(getSwiftNameAttribute(member))
                     member.copy(
-                        name = member.name + "_",
+                        name = name + "_",
                         propertyAttributes = null,
-                        declarationAttributes = listOf(buildMangledSwiftNamePropertyAttribute(attr.mangleAttribute()))
+                        declarationAttributes = null
                     )
                 } else {
                     member.copy(
-                        name = member.name,
-                        propertyAttributes = "getter=${member.name}_",
+                        name = name,
+                        propertyAttributes = "getter=${name}_",
                         declarationAttributes = null
                     )
                 }
-                mangledProperties.add(getSwiftNameAttribute(copy))
                 copy
             } else {
-                mangledProperties.add(key)
+                mangledProperties.add(name)
                 member
             }
-        } else if (member.isSwiftNameMethod()) {
-            mangledProperties.add(getSwiftNameAttribute(member as ObjCMethod).replace("()", ""))
+        } else if (member is ObjCMethod && member.selectors.size == 1 && member.parameters.isEmpty()) {
+            mangledProperties.add(member.selectors[0])
             member
         } else {
             // Leave it as it is since it is neither property, nor method
             member
         }
     }
-}
-
-private fun buildMangledSwiftNamePropertyAttribute(attribute: ObjCMemberDetails): String {
-    return "swift_name(\"${attribute.name + attribute.postfix}\")"
 }

native/objcexport-header-generator/impl/analysis-api/src/org/jetbrains/kotlin/objcexport/mangling/copyObjCStub.kt

@@ -27,14 +27,12 @@ internal fun ObjCProperty.copy(
  */
 internal fun ObjCMethod.copy(
     mangledSelectors: List<String>,
-    mangledParameters: List<String>,
-    swiftNameAttribute: String,
     containingStubName: String,
 ): ObjCMethod {
     val selectorsSize = mangledSelectors.size
     val parametersSize = this.parameters.size
     val methodName = this.name
-    require((selectorsSize == parametersSize) || (selectorsSize == 1 && mangledParameters.isEmpty())) {
+    require((selectorsSize == parametersSize) || (selectorsSize == 1 && parametersSize == 0)) {
         "'$containingStubName.$methodName': selectors of doesn't match parameters count: " +
             "selectors($mangledSelectors): $selectorsSize, " +
             "parameters(${this.parameters.joinToString { it.name }}): $parametersSize"
@@ -47,9 +45,70 @@ internal fun ObjCMethod.copy(
         selectors = mangledSelectors,
         parameters = this.parameters,
         attributes = this.attributes.map { attr ->
-            if (attr.startsWith("swift_name")) swiftNameAttribute else attr
+            if (attr.startsWith("swift_name")) remangledSwiftName(mangledSelectors, this.attributes) else attr
         },
         extras = this.extras
     )
+}
 
-}
+/**
+ * Create a swift name based on the selectors and attributes.
+ */
+internal fun ObjCMethod.remangledSwiftName(mangledSelectors: List<String>, attributes: List<String>): String {
+    fun isConstructor(attributes: List<String>) : Boolean {
+        return attributes.contains("objc_designated_initializer")
+    }
+
+    val swiftName = StringBuilder("swift_name(\"")
+    val count = if (mangledSelectors[0].endsWith(":")) mangledSelectors.size else mangledSelectors.size - 1
+    if (count == 0) {
+        // - (void)bar; -> bar()
+        swiftName.append(mangledSelectors[0] + "()")
+    } else {
+        val selector = mangledSelectors[0]
+        val lastUppercaseChar = selector.indexOfLast { it.isUpperCase() }
+        if (isConstructor(attributes)) {
+            // - (instancetype)initWithA:...; -> init(a:)
+            var prefix = selector.take(lastUppercaseChar)
+            if (prefix.endsWith("With")) {
+                prefix = prefix.dropLast(4)
+            }
+            swiftName.append(
+                prefix
+                    + "("
+                    + selector.substring(lastUppercaseChar).replaceFirstChar { it.lowercase() })
+        } else if (lastUppercaseChar == -1 && selector.endsWith("_:")) {
+            //- (Foo *)days_... -> days(__:...)
+            //- (Foo *)days__... -> days(___:...)
+            val index = selector.indexOf("_")
+            swiftName.append(selector.substring(0, index) + "(")
+            for (i in index until selector.length) {
+                swiftName.append("_")
+            }
+            swiftName.append(":")
+        } else {
+            if (lastUppercaseChar == -1) {
+                // - (void)bar:; -> bar:(_)
+                swiftName.append(selector.dropLast(1) + "(_")
+                if (count > 1) {
+                    // - (void)bar:...; -> bar:(_:...
+                    swiftName.append(":")
+                }
+            } else {
+                // - (void)doBar:...; -> do(bar:...)
+                swiftName.append(
+                    selector.take(lastUppercaseChar)
+                        + "("
+                        + selector.substring(lastUppercaseChar).replaceFirstChar { it.lowercase() })
+            }
+        }
+        if (count > 1) {
+            for (i in 1 until count) {
+                swiftName.append(mangledSelectors[i])
+            }
+        }
+        swiftName.append(")")
+    }
+    swiftName.append("\")")
+    return swiftName.toString()
+}