[Macro] Add plugin test

Author: rintaro

Examples/Package.swift

@@ -10,6 +10,7 @@ let package = Package(
   products: [
     .executable(name: "AddOneToIntegerLiterals", targets: ["AddOneToIntegerLiterals"]),
     .executable(name: "CodeGenerationUsingSwiftSyntaxBuilder", targets: ["CodeGenerationUsingSwiftSyntaxBuilder"]),
+    .executable(name: "ExamplePlugin", targets: ["ExamplePlugin"]),
   ],
   dependencies: [
     .package(path: "../")
@@ -20,17 +21,21 @@ let package = Package(
       dependencies: [
         .product(name: "SwiftParser", package: "swift-syntax"),
         .product(name: "SwiftSyntax", package: "swift-syntax"),
-      ],
-      path: ".",
-      exclude: ["README.md", "CodeGenerationUsingSwiftSyntaxBuilder.swift"]
+      ]
     ),
     .executableTarget(
       name: "CodeGenerationUsingSwiftSyntaxBuilder",
       dependencies: [
         .product(name: "SwiftSyntaxBuilder", package: "swift-syntax")
-      ],
-      path: ".",
-      exclude: ["README.md", "AddOneToIntegerLiterals.swift"]
+      ]
     ),
+    .executableTarget(
+      name: "ExamplePlugin",
+      dependencies: [
+        .product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
+        .product(name: "SwiftSyntax", package: "swift-syntax"),
+        .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+        .product(name: "SwiftDiagnostics", package: "swift-syntax"),
+      ])
   ]
 )

Examples/README.md

@@ -2,8 +2,9 @@
 
 Each example can be executed by navigating into this folder and running `swift run <example> <arguments>`. There is the following set of examples available:
 
-- [AddOneToIntegerLiterals](AddOneToIntegerLiterals.swift): Command line tool to add 1 to every integer literal in a source file
-- [CodeGenerationUsingSwiftSyntaxBuilder](CodeGenerationUsingSwiftSyntaxBuilder.swift): Code-generate a simple source file using SwiftSyntaxBuilder
+- [AddOneToIntegerLiterals](Sources/AddOneToIntegerLiterals/AddOneToIntegerLiterals.swift): Command line tool to add 1 to every integer literal in a source file
+- [CodeGenerationUsingSwiftSyntaxBuilder](Sources/CodeGenerationUsingSwiftSyntaxBuilder/CodeGenerationUsingSwiftSyntaxBuilder.swift): Code-generate a simple source file using SwiftSyntaxBuilder
+- [ExamplePlugin](Sources/ExamplePlugn): Compiler plugin executable using [`SwiftCompilerPlugin`](../Sources/SwiftCompilerPlugin)
 
 ## Some Example Usages
 

Examples/AddOneToIntegerLiterals.swift renamed to Examples/Sources/AddOneToIntegerLiterals/AddOneToIntegerLiterals.swift

@@ -0,0 +1,10 @@
+import SwiftCompilerPlugin
+import SwiftSyntaxMacros
+
+@main
+struct ThePlugin: CompilerPlugin {
+  var providingMacros: [Macro.Type] = [
+    EchoExpressionMacro.self,
+    MetadataMacro.self
+  ]
+}

Examples/CodeGenerationUsingSwiftSyntaxBuilder.swift renamed to Examples/Sources/CodeGenerationUsingSwiftSyntaxBuilder/CodeGenerationUsingSwiftSyntaxBuilder.swift

@@ -0,0 +1,39 @@
+import SwiftSyntax
+import SwiftSyntaxBuilder
+import SwiftSyntaxMacros
+
+/// Returns the first argument prepending a comment '/* echo */'.
+struct EchoExpressionMacro: ExpressionMacro {
+  static func expansion<
+    Node: FreestandingMacroExpansionSyntax,
+    Context: MacroExpansionContext
+  >(
+    of node: Node,
+    in context: Context
+  ) throws -> ExprSyntax {
+    let expr: ExprSyntax = node.argumentList.first!.expression
+    return expr.with(\.leadingTrivia, [.blockComment("/* echo */")])
+  }
+}
+
+/// Add a static property `__metadata__`.
+struct MetadataMacro: MemberMacro {
+  static func expansion<
+    Declaration: DeclGroupSyntax,
+    Context: MacroExpansionContext
+  >(
+    of node: SwiftSyntax.AttributeSyntax,
+    providingMembersOf declaration: Declaration,
+    in context: Context
+  ) throws -> [DeclSyntax] {
+    guard let cls = declaration.as(ClassDeclSyntax.self) else {
+      return []
+    }
+    let className = cls.identifier.trimmedDescription
+    return [
+      """
+        static var __metadata__: [String: String] { ["name": "\(raw: className)"] }
+        """
+    ]
+  }
+}

Examples/Sources/ExamplePlugin/ExamplePlugin.swift

@@ -564,6 +564,12 @@ def run_lit_tests(toolchain: str, build_dir: Optional[str], release: bool,
         ["--param", "INCR_TRANSFER_ROUND_TRIP.PY=" + INCR_TRANSFER_ROUNDTRIP_EXEC]
     )
 
+    build_subdir = 'release' if release else 'debug'
+    package_build_dir = build_dir + '/' + build_subdir
+
+    lit_call.extend(["--param", "BUILD_DIR=" + package_build_dir])
+    lit_call.extend(["--param", "TOOLCHAIN=" + toolchain])
+
     # Print all failures
     lit_call.extend(["--verbose"])
     # Don't show all commands if verbose is not enabled
@@ -689,6 +695,7 @@ def test_command(args: argparse.Namespace) -> None:
         )
 
         builder.buildProduct("lit-test-helper")
+        builder.buildExample("ExamplePlugin")
 
         run_tests(
             toolchain=args.toolchain,

Examples/Sources/ExamplePlugin/Macros.swift

@@ -0,0 +1,33 @@
+// REQUIRES: platform=Darwin
+//
+// RUN: %empty-directory(%t)
+//
+// RUN: %swift-frontend -typecheck -swift-version 5 \
+// RUN:   -enable-experimental-feature Macros \
+// RUN:   -dump-macro-expansions \
+// RUN:   -load-plugin-executable %build_dir/ExamplePlugin#ExamplePlugin \
+// RUN    -module-name MyApp \
+// RUN:   %s > %t/expansions-dump.txt 2>&1
+//
+// RUN: %FileCheck %s < %t/expansions-dump.txt
+
+@freestanding(expression)
+macro echo<T>(_: T) -> T = #externalMacro(module: "ExamplePlugin", type: "EchoExpressionMacro")
+
+@attached(member)
+macro Metadata() = #externalMacro(module: "ExamplePlugin", type: "MetadataMacro")
+
+@Metadata
+class MyClass {
+  var value: Int = #echo(12)
+}
+
+// CHECK-LABEL: @__swiftmacro_21compiler_plugin_basic7MyClassC8MetadatafMm_.swift
+// CHECK-NEXT: ------------------------------
+// CHECK-NEXT: static var __metadata__: [String: String] { ["name": "MyClass"] }
+// CHECK-NEXT: ------------------------------
+
+// CHECK-LABEL: @__swiftmacro_21compiler_plugin_basic7MyClassC5valueSivpfi4echofMf_.swift as Int
+// CHECK-NEXT: ------------------------------
+// CHECK-NEXT: /* echo */12
+// CHECK-NEXT: ------------------------------

build-script.py

@@ -11,6 +11,7 @@
 # -----------------------------------------------------------------------------
 
 import lit
+import platform
 import tempfile
 
 
@@ -25,6 +26,11 @@ def inferSwiftBinaryImpl(binaryName, envVarName):
     if execPath:
         return execPath
 
+    # Find in the toolchain.
+    execPath = lit_config.params.get('TOOLCHAIN') + '/bin/' + binaryName
+    if os.path.exists(execPath):
+        return execPath
+
     # Lastly, look in the path.
     return lit.util.which(binaryName, config.environment["PATH"])
 
@@ -53,10 +59,21 @@ config.suffixes = [".swift"]
 config.test_format = lit.formats.ShTest(execute_external=True)
 config.test_exec_root = tempfile.gettempdir()
 
+config.build_dir = lit_config.params.get("BUILD_DIR")
 config.filecheck = inferSwiftBinary("FileCheck")
 config.incr_transfer_round_trip = inferSwiftBinary("incr_transfer_round_trip.py")
 config.lit_test_helper = inferSwiftBinary("lit-test-helper")
+config.swift = inferSwiftBinary("swift")
+config.swiftc = inferSwiftBinary("swiftc")
+config.swift_frontend = inferSwiftBinary("swift-frontend")
+
+# Use features like this in lit:
+#   // REQUIRES: platform=<platform>
+# where <platform> is Linux or Darwin
+# Add a platform feature.
+config.available_features.add("platform="+platform.system())
 
+config.substitutions.append(("%build_dir", config.build_dir))
 config.substitutions.append(
     ("%empty-directory\(([^)]+)\)", 'rm -rf "\\1" && mkdir -p "\\1"')
 )
@@ -69,3 +86,6 @@ config.substitutions.append(
     )
 )
 config.substitutions.append(("%lit-test-helper", config.lit_test_helper))
+config.substitutions.append(("%swiftc", config.swiftc))
+config.substitutions.append(("%swift", config.swift))
+config.substitutions.append(("%swift-frontend", config.swift_frontend))