Experimenting with the Kotlin Compiler

Slides for my talk about the Kotlin Compiler, given at Android Makers 2020.

Transcript

1. Jossi Wolf @jossiwolf Experimenting with the Kotlin Compiler
2. @jossiwolf
3. @jossiwolf # SDKs should be simple
4. @jossiwolf class ChatSdk
5. @jossiwolf interface MessageFeature { fun poll(): List<Message> fun push(message: Message) }
6. @jossiwolf class ChatSdk: MessageFeature { private val messages = mutableListOf<Message>() override fun poll(): List<Message> = messages override fun push(message: Message) { messages.add(message) } }
7. @jossiwolf class SimpleMessenger: MessageFeature { private val messages = mutableListOf<Message>() override fun poll(): List<Message> = messages override fun push(message: Message) { messages.add(message) } }
8. @jossiwolf class ChatSdk: MessageFeature by SimpleMessenger()
9. @jossiwolf public final class ChatSdk implements MessageFeature
10. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
11. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
12. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
13. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
14. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
15. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger(); @NotNull public List poll() { return this.$$delegate_0.poll(); } public void push(@NotNull Message message) { Intrinsics.checkParameterIsNotNull(message, "message"); this.$$delegate_0.push(message); } }
16. @jossiwolf class ChatSdk: MessageFeature by SimpleMessenger()
17. @jossiwolf # Kotlin is open source!
18. @jossiwolf github.com/jetbrains/kotlin
19. @jossiwolf $ git clone github.com/JetBrains/kotlin.git
20. @jossiwolf To build Kotlin, you need different JDK versions! - github.com/jetbrains/kotlin #build-environment-requirements
21. @jossiwolf
22. @jossiwolf # Running Kotlin
23. @jossiwolf
24. @jossiwolf
25. @jossiwolf # The Kotlin Compiler
26. @jossiwolf Compiler .kt Bytecode
27. @jossiwolf Compiler https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
28. @jossiwolf Compiler Lexer https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
29. @jossiwolf Compiler Parser Lexer https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
30. @jossiwolf Compiler Parser Lexer Codegen https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
31. @jossiwolf Compiler Parser https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
32. @jossiwolf Compiler Parser Syntax Analyzer https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
33. @jossiwolf Compiler Parser Syntax Analyzer Creates AST https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
34. @jossiwolf Compiler Parser Syntax Analyzer Semantic Analyzer Creates AST https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
35. @jossiwolf Abstract Syntax Tree
36. @jossiwolf Abstract Syntax Tree @Annotation1("abc") // line comment between annotations @Annotation2("\${123}") fun parse() {} https://github.com/kotlinx/ast
37. @jossiwolf Abstract Syntax Tree PackageHeader() importList KlassDeclaration(fun parse) KlassAnnotation(Annotation1) KlassArgument() KlassString "abc" KlassAnnotation(Annotation2) KlassArgument() KlassString Escape("\$") "{123}" https://github.com/kotlinx/ast
38. @jossiwolf Compiler Parser Lexer Codegen https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course Creates PSI
39. @jossiwolf
40. @jossiwolf Compiler Parser Lexer Codegen https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
41. @jossiwolf Compiler Parser Lexer Codegen Intermediate Code Generator https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
42. @jossiwolf Compiler Parser Lexer Codegen Intermediate Code Generator Non-optimised IR https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
43. @jossiwolf Compiler Parser Lexer Codegen Intermediate Code Generator Intermediate Code Optimizer Non-optimised IR https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
44. @jossiwolf Compiler Frontend Parser Lexer Backend Codegen https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
45. @jossiwolf
46. @jossiwolf class ChatSdk: MessageFeature by SimpleMessenger()
47. @jossiwolf
48. @jossiwolf KEEP = Kotlin Evolution and Enhancement Process
49. @jossiwolf slack.kotlinlang.org #language-design
50. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
51. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature fun swapMessenger() { messenger = when (messenger) { is SimpleMessenger -> ComplexMessenger() is ComplexMessenger -> SimpleMessenger() } } }
52. @jossiwolf lateinit
53. @jossiwolf lateinit
54. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
55. @jossiwolf CMD + Shift + F
56. @jossiwolf
57. @jossiwolf KtModifierKeywordToken LATEINIT_KEYWORD = KtModifierKeywordToken.softKeywordModifier("lateinit"); KtModifierKeywordToken DATA_KEYWORD = KtModifierKeywordToken.softKeywordModifier("data"); KtModifierKeywordToken INLINE_KEYWORD = KtModifierKeywordToken.softKeywordModifier("inline"); KtModifierKeywordToken NOINLINE_KEYWORD = KtModifierKeywordToken.softKeywordModifier("noinline"); KtTokens.java
58. @jossiwolf KtModifierKeywordToken CLASSDELEGATE_KEYWORD = KtModifierKeywordToken.softKeywordModifier("classdelegate"); KtModifierKeywordToken LATEINIT_KEYWORD = KtModifierKeywordToken.softKeywordModifier("lateinit"); KtModifierKeywordToken DATA_KEYWORD = KtModifierKeywordToken.softKeywordModifier("data"); KtModifierKeywordToken INLINE_KEYWORD = KtModifierKeywordToken.softKeywordModifier("inline"); KtModifierKeywordToken NOINLINE_KEYWORD = KtModifierKeywordToken.softKeywordModifier("noinline"); KtTokens.java
59. @jossiwolf classdelegate var messenger: MessageFeature
60. @jossiwolf # Codegen
61. @jossiwolf Compiler Parser Lexer Codegen https://github.com/ahinchman1/Kotlin-Compiler-Crash-Course
62. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
63. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
64. @jossiwolf ConstructorCodegen.java
65. @jossiwolf ConstructorCodegen #generatePrimaryConstructorImpl
66. @jossiwolf public final class ChatSdk implements MessageFeature { // $FF: synthetic field private final SimpleMessenger $$delegate_0 = new SimpleMessenger();
67. @jossiwolf 1. Generate Delegate Expressions
68. @jossiwolf for (specifier: myClass.getSuperTypeListEntries()) { if (specifier instanceof KtDelegatedSuperTypeEntry) { genCallToDelegatorByExpressionSpecifier( iv, codegen, (KtDelegatedSuperTypeEntry) specifier, fieldsInfo ); } }
69. @jossiwolf for (specifier: myClass.getSuperTypeListEntries()) { if (specifier instanceof KtDelegatedSuperTypeEntry) { genCallToDelegatorByExpressionSpecifier( iv, codegen, (KtDelegatedSuperTypeEntry) specifier, fieldsInfo ); } }
70. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
71. @jossiwolf for (specifier: myClass.getSuperTypeListEntries()) { if (specifier instanceof KtDelegatedSuperTypeEntry) { genCallToDelegatorByExpressionSpecifier( iv, codegen, (KtDelegatedSuperTypeEntry) specifier, fieldsInfo ); } }
72. @jossiwolf for (specifier: myClass.getSuperTypeListEntries()) { if (specifier instanceof KtDelegatedSuperTypeEntry) { genCallToDelegatorByExpressionSpecifier( iv, codegen, (KtDelegatedSuperTypeEntry) specifier, fieldsInfo ); } }
73. @jossiwolf 2. Generate Fields
74. @jossiwolf List<ValueParameterDescriptor> parameters = constructorDescriptor.getValueParameters(); for (KtParameter parameter : classBodyCodegen.getPrimaryConstructorParameters()) { if (parameter.hasValOrVar()) { VariableDescriptor descriptor = parameters.get(curParam); Type type = typeMapper.mapType(descriptor); iv.load(0, classAsmType); iv.load(codegen.myFrameMap.getIndex(descriptor), type); PropertyDescriptor propertyDescriptor = bindingContext.get(BindingContext.PRIMARY_CONSTRUCTOR_PARAMETER, parameter); iv.putfield(classAsmType.getInternalName(), context.getFieldName(propertyDescriptor, false), type.getDescriptor()); } curParam++; }
75. @jossiwolf 3. Generate Member Initializers
76. @jossiwolf if (!isObject(descriptor)) { memberCodegen.generateInitializers( () -> codegen ); }
77. @jossiwolf 1. Generate Delegate Expressions 2. Generate Fields 3. Generate Initializers
78. @jossiwolf 1. Generate Fields 2. Generate Delegate Expressions 3. Generate Initializers
79. @jossiwolf class ChatSdk: MessageFeature by messenger { classdelegate var messenger: MessageFeature }
80. @jossiwolf public final class ChatSdk implements MessageFeature { public MessageFeature messenger; public final MessageFeature getMessenger() { return this.messenger; } public final void setMessenger(MessageFeature var1) { this.messenger = var1; } public List poll() { return this.messenger.poll(); } public void push(Message message) { this.messenger.push(message); } }
81. @jossiwolf public final class ChatSdk implements MessageFeature { public MessageFeature messenger; public final MessageFeature getMessenger() { return this.messenger; } public final void setMessenger(MessageFeature var1) { this.messenger = var1; } public List poll() { return this.messenger.poll(); } public void push(Message message) { this.messenger.push(message); } }
82. @jossiwolf public final class ChatSdk implements MessageFeature { public MessageFeature messenger; public final MessageFeature getMessenger() { return this.messenger; } public final void setMessenger(MessageFeature var1) { this.messenger = var1; } public List poll() { return this.messenger.poll(); } public void push(Message message) { this.messenger.push(message); } }
83. @jossiwolf class ChatSdk: MessageFeature by messenger { lateinit classdelegate var messenger: MessageFeature }
84. @jossiwolf PSI - KotlinStubVersions.kt - Lexer - KtTokens.java Resolution - FakeCallableDescriptorForObject.kt - Scopes - Scopes.kt - MemberScope.kt - ClassResolutionScopesSupport.kt - DelegationValueArgument.java - TypeResolver.kt for modifying the scope - DescriptorResolver.java - BodyResolver.java Codegen - DelegationFieldsInfo.java - ImplementationBodyCodegen.java - ConstructorCodegen.java - CodegenUtil.kt
85. @jossiwolf IR - IrProperty.kt Backend - MoveCompanionObjectFieldsLowering.kt - SharedVariablesManager.kt Descriptors - JavaPropertyDescriptor.java - ValueParameterDescriptor.java - VariableDescriptor.java - PropertyDescriptorImpl.java - ErrorUtils.java Serialization Adjustments Debugger Tinkering Scripting Adjustments
86. @jossiwolf
87. @jossiwolf github.com/jossiwolf/kotlin/pull/1/files
88. @jossiwolf # Awesome Resources
89. @jossiwolf - github.com/ahinchman1/Kotlin-Compiler-Crash-Course - kotlin.github.io/kotlin-spec/ - github.com/jossiwolf/kotlin/pull/1/files - KotlinLang Slack - #kontributors - #arrow-meta - #compiler - #language-proposals
90. Jossi Wolf @jossiwolf Experimenting with the Kotlin Compiler