[InterfaceGen] Print bodies of inlinable functions in textual interfaces (#19224)

* Introduce stored inlinable function bodies

* Remove serialization changes

* [InterfaceGen] Print inlinable function bodies

* Clean up a little bit and add test

* Undo changes to InlinableText

* Add serialization and deserialization for inlinable body text

* Allow parser to parse accessor bodies in interfaces

* Fix some tests

* Fix remaining tests

* Add tests for usableFromInline decls

* Add comments

* Clean up function body printing throughout

* Add tests for subscripts

* Remove comment about subscript inlinable text

* Address some comments

* Handle lack of @objc on Linux

Author: Harlan

include/swift/AST/Decl.h

@@ -4977,7 +4977,10 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
     TypeChecked,
 
     /// This is a memberwise initializer that will be synthesized by SILGen.
-    MemberwiseInitializer
+    MemberwiseInitializer,
+
+    /// Function body text was deserialized from a .swiftmodule.
+    Deserialized
 
     // This enum currently needs to fit in a 3-bit bitfield.
   };
@@ -4999,6 +5002,9 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
     /// BodyKind::TypeChecked.
     BraceStmt *Body;
 
+    /// This enum member is active if getBodyKind() is BodyKind::Deserialized.
+    StringRef BodyStringRepresentation;
+
     /// This enum member is active if getBodyKind() == BodyKind::Synthesize.
     BodySynthesizer Synthesizer;
 
@@ -5093,6 +5099,11 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
     return getBodyKind() != BodyKind::None;
   }
 
+  /// Returns true if the text of this function's body can be retrieved either
+  /// by extracting the text from the source buffer or reading the inlinable
+  /// body from a deserialized swiftmodule.
+  bool hasInlinableBodyText() const;
+
   /// Returns the function body, if it was parsed, or nullptr otherwise.
   ///
   /// Note that a null return value does not imply that the source code did not
@@ -5156,6 +5167,18 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
       setBodyKind(BodyKind::TypeChecked);
   }
 
+  /// Gets the body of this function, stripping the unused portions of #if
+  /// configs inside the body. If this function was not deserialized from a
+  /// .swiftmodule, this body is reconstructed from the original
+  /// source buffer.
+  StringRef getInlinableBodyText(SmallVectorImpl<char> &scratch) const;
+
+  void setBodyStringRepresentation(StringRef body) {
+    assert(getBodyKind() == BodyKind::None);
+    setBodyKind(BodyKind::Deserialized);
+    BodyStringRepresentation = body;
+  }
+
   bool isBodyTypeChecked() const {
     return getBodyKind() == BodyKind::TypeChecked;
   }

include/swift/AST/PrintOptions.h

@@ -23,6 +23,7 @@
 #include <vector>
 
 namespace swift {
+class ASTPrinter;
 class GenericEnvironment;
 class CanType;
 class Decl;
@@ -356,10 +357,9 @@ struct PrintOptions {
   QualifyNestedDeclarations ShouldQualifyNestedDeclarations =
       QualifyNestedDeclarations::Never;
 
-  /// \brief If this is not \c nullptr then functions (including accessors and
-  /// constructors) will be printed with a body that is determined by this
-  /// function.
-  std::function<std::string(const ValueDecl *)> FunctionBody;
+  /// \brief If this is not \c nullptr then function bodies (including accessors
+  /// and constructors) will be printed by this function.
+  std::function<void(const ValueDecl *, ASTPrinter &)> FunctionBody;
 
   BracketOptions BracketOptions;
 

include/swift/Serialization/DeclTypeRecordNodes.def

@@ -180,6 +180,7 @@ OTHER(NORMAL_PROTOCOL_CONFORMANCE_ID, 246)
 OTHER(PROTOCOL_CONFORMANCE_XREF, 247)
 OTHER(MEMBERS, 248)
 OTHER(XREF, 249)
+OTHER(INLINABLE_BODY_TEXT, 250)
 
 #undef RECORD
 #undef DECLTYPERECORDNODES_HAS_RECORD_VAL

include/swift/Serialization/ModuleFile.h

@@ -884,6 +884,9 @@ class ModuleFile
 
   /// Reads a foreign error conformance from \c DeclTypeCursor, if present.
   Optional<ForeignErrorConvention> maybeReadForeignErrorConvention();
+
+  /// Reads inlinable body text from \c DeclTypeCursor, if present.
+  Optional<StringRef> maybeReadInlinableBodyText();
 };
 
 template <typename T, typename RawData>

include/swift/Serialization/ModuleFormat.h

@@ -55,7 +55,7 @@ const uint16_t VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t VERSION_MINOR = 443; // Last change: serialize unsubstituted type alias type
+const uint16_t VERSION_MINOR = 444; // Last change: inlinable body text
 
 using DeclIDField = BCFixed<31>;
 
@@ -979,8 +979,11 @@ namespace decls_block {
     BCVBR<5>,     // number of parameter name components
     BCArray<IdentifierIDField> // name components,
                                // followed by TypeID dependencies
-    // Trailed by its generic parameters, if any, followed by the parameter
-    // patterns.
+    // This record is trailed by:
+    // - its generic parameters, if any
+    // - its parameter patterns,
+    // - the foreign error convention, if any
+    // - inlinable body text, if any
   >;
 
   using VarLayout = BCRecordLayout<
@@ -1044,6 +1047,8 @@ namespace decls_block {
     // - its _silgen_name, if any
     // - its generic parameters, if any
     // - body parameter patterns
+    // - the foreign error convention, if any
+    // - inlinable body text, if any
   >;
 
   // TODO: remove the unnecessary FuncDecl components here
@@ -1073,6 +1078,8 @@ namespace decls_block {
     // - its _silgen_name, if any
     // - its generic parameters, if any
     // - body parameter patterns
+    // - the foreign error convention, if any
+    // - inlinable body text, if any
   >;
 
   using PatternBindingLayout = BCRecordLayout<
@@ -1176,6 +1183,12 @@ namespace decls_block {
     BCFixed<1>,  // implicit?
     BCFixed<1>,  // objc?
     GenericEnvironmentIDField // generic environment
+    // This record is trailed by its inlinable body text
+  >;
+
+  using InlinableBodyTextLayout = BCRecordLayout<
+    INLINABLE_BODY_TEXT,
+    BCBlob // body text
   >;
 
   using ParameterListLayout = BCRecordLayout<

lib/AST/ASTPrinter.cpp

@@ -81,6 +81,15 @@ PrintOptions PrintOptions::printTextualInterfaceFile() {
   result.SkipImports = true;
   result.OmitNameOfInaccessibleProperties = true;
 
+  result.FunctionBody = [](const ValueDecl *decl, ASTPrinter &printer) {
+    auto AFD = dyn_cast<AbstractFunctionDecl>(decl);
+    if (!AFD || !AFD->hasInlinableBodyText()) return;
+    if (AFD->getResilienceExpansion() != ResilienceExpansion::Minimal)
+      return;
+    SmallString<128> scratch;
+    printer << " " << AFD->getInlinableBodyText(scratch);
+  };
+
   class ShouldPrintForTextualInterface : public ShouldPrintChecker {
     bool shouldPrint(const Decl *D, const PrintOptions &options) override {
       // Skip anything that isn't 'public' or '@usableFromInline'.
@@ -645,6 +654,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
 
   void printAttributes(const Decl *D);
   void printTypedPattern(const TypedPattern *TP);
+  void printBraceStmt(const BraceStmt *stmt, bool newlineIfEmpty = true);
 
 public:
   void printPattern(const Pattern *pattern);
@@ -686,6 +696,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
   void printGenericDeclGenericParams(GenericContext *decl);
   void printGenericDeclGenericRequirements(GenericContext *decl);
   void printInherited(const Decl *decl);
+  void printBodyIfNecessary(const AbstractFunctionDecl *decl);
 
   void printEnumElement(EnumElementDecl *elt);
 
@@ -1471,6 +1482,29 @@ bool PrintAST::shouldPrint(const Decl *D, bool Notify) {
   return Result;
 }
 
+void PrintAST::printBraceStmt(const BraceStmt *stmt, bool newlineIfEmpty) {
+  Printer << "{";
+  if (printASTNodes(stmt->getElements()) || newlineIfEmpty) {
+    Printer.printNewline();
+    indent();
+  }
+  Printer << "}";
+}
+
+void PrintAST::printBodyIfNecessary(const AbstractFunctionDecl *decl) {
+  if (auto BodyFunc = Options.FunctionBody) {
+    BodyFunc(decl, Printer);
+    indent();
+    return;
+  }
+
+  if (!Options.FunctionDefinitions || !decl->getBody())
+    return;
+
+  Printer << " ";
+  printBraceStmt(decl->getBody(), /*newlineIfEmpty*/!isa<AccessorDecl>(decl));
+}
+
 static bool isAccessorAssumedNonMutating(AccessorKind kind) {
   switch (kind) {
   case AccessorKind::Get:
@@ -1630,26 +1664,37 @@ void PrintAST::printAccessors(AbstractStorageDecl *ASD) {
       Printer << " ";
       Printer.printKeyword(getAccessorLabel(Accessor));
     } else {
-      Printer.printNewline();
-      IndentRAII IndentMore(*this);
+      {
+        IndentRAII IndentMore(*this);
+        indent();
+        visit(Accessor);
+      }
       indent();
-      visit(Accessor);
+      Printer.printNewline();
     }
   };
 
-  Printer << " {";
   if ((PrintAbstract ||
        (impl.getReadImpl() == ReadImplKind::Get && ASD->getGetter())) &&
       !ASD->supportsMutation() && !ASD->isGetterMutating() &&
       PrintAccessorBody && !Options.FunctionDefinitions) {
     // Omit the 'get' keyword. Directly print getter
     if (auto BodyFunc = Options.FunctionBody) {
-      Printer.printNewline();
-      IndentRAII IndentBody(*this);
+      BodyFunc(ASD->getGetter(), Printer);
       indent();
-      Printer << BodyFunc(ASD->getGetter());
+      return;
     }
-  } else if (PrintAbstract) {
+    Printer.printNewline();
+    indent();
+    return;
+  }
+
+  Printer << " {";
+
+  if (PrintAccessorBody)
+    Printer.printNewline();
+
+  if (PrintAbstract) {
     PrintAccessor(ASD->getGetter());
     if (ASD->supportsMutation())
       PrintAccessor(ASD->getSetter());
@@ -1693,12 +1738,16 @@ void PrintAST::printAccessors(AbstractStorageDecl *ASD) {
       break;
     }
   }
-  if (PrintAccessorBody) {
-    Printer.printNewline();
-    indent();
-  } else
+
+  if (!PrintAccessorBody)
     Printer << " ";
+
   Printer << "}";
+
+  if (!PrintAbstract)
+    Printer.printNewline();
+
+  indent();
 }
 
 void PrintAST::printMembersOfDecl(Decl *D, bool needComma,
@@ -2497,7 +2546,6 @@ void PrintAST::visitAccessorDecl(AccessorDecl *decl) {
       [&]{
         Printer << getAccessorLabel(decl);
       });
-    Printer << " {";
     break;
   case AccessorKind::Set:
   case AccessorKind::WillSet:
@@ -2515,24 +2563,9 @@ void PrintAST::visitAccessorDecl(AccessorDecl *decl) {
           }
         }
       });
-    Printer << " {";
   }
-  if (auto BodyFunc = Options.FunctionBody) {
-    {
-      IndentRAII IndentBody(*this);
-      indent();
-      Printer.printNewline();
-      Printer << BodyFunc(decl);
-    }
-    indent();
-    Printer.printNewline();
-  } else if (Options.FunctionDefinitions && decl->getBody()) {
-    if (printASTNodes(decl->getBody()->getElements())) {
-      Printer.printNewline();
-      indent();
-    }
-  }
-  Printer << "}";
+
+  printBodyIfNecessary(decl);
 }
 
 void PrintAST::visitFuncDecl(FuncDecl *decl) {
@@ -2604,22 +2637,7 @@ void PrintAST::visitFuncDecl(FuncDecl *decl) {
     printGenericDeclGenericRequirements(decl);
   }
 
-  if (auto BodyFunc = Options.FunctionBody) {
-    Printer << " {";
-    Printer.printNewline();
-    {
-      IndentRAII IndentBody(*this);
-      indent();
-      Printer << BodyFunc(decl);
-    }
-    indent();
-    Printer.printNewline();
-    Printer << "}";
-
-  } else if (Options.FunctionDefinitions && decl->getBody()) {
-    Printer << " ";
-    visit(decl->getBody());
-  }
+  printBodyIfNecessary(decl);
 }
 
 void PrintAST::printEnumElement(EnumElementDecl *elt) {
@@ -2788,21 +2806,7 @@ void PrintAST::visitConstructorDecl(ConstructorDecl *decl) {
 
   printGenericDeclGenericRequirements(decl);
 
-  if (auto BodyFunc = Options.FunctionBody) {
-    Printer << " {";
-    {
-      Printer.printNewline();
-      IndentRAII IndentBody(*this);
-      indent();
-      Printer << BodyFunc(decl);
-    }
-    indent();
-    Printer.printNewline();
-    Printer << "}";
-  } else if (Options.FunctionDefinitions && decl->getBody()) {
-    Printer << " ";
-    visit(decl->getBody());
-  }
+  printBodyIfNecessary(decl);
 }
 
 void PrintAST::visitDestructorDecl(DestructorDecl *decl) {
@@ -2814,12 +2818,7 @@ void PrintAST::visitDestructorDecl(DestructorDecl *decl) {
       Printer << "deinit";
     });
 
-  if (!Options.FunctionDefinitions || !decl->getBody()) {
-    return;
-  }
-
-  Printer << " ";
-  visit(decl->getBody());
+  printBodyIfNecessary(decl);
 }
 
 void PrintAST::visitInfixOperatorDecl(InfixOperatorDecl *decl) {
@@ -2929,11 +2928,7 @@ void PrintAST::visitMissingMemberDecl(MissingMemberDecl *decl) {
 }
 
 void PrintAST::visitBraceStmt(BraceStmt *stmt) {
-  Printer << "{";
-  printASTNodes(stmt->getElements());
-  Printer.printNewline();
-  indent();
-  Printer << "}";
+  printBraceStmt(stmt);
 }
 
 void PrintAST::visitReturnStmt(ReturnStmt *stmt) {

lib/AST/ASTVerifier.cpp

@@ -490,6 +490,7 @@ class Verifier : public ASTWalker {
       case AbstractFunctionDecl::BodyKind::TypeChecked:
       case AbstractFunctionDecl::BodyKind::Skipped:
       case AbstractFunctionDecl::BodyKind::MemberwiseInitializer:
+      case AbstractFunctionDecl::BodyKind::Deserialized:
         return true;
 
       case AbstractFunctionDecl::BodyKind::Unparsed: