Merge pull request swiftlang#69007 from nate-chandler/swiftcompilersources/test-bridging-registration-cleanup

[SwiftCompilerSources] Simplified test registration.

Author: nate-chandler

SwiftCompilerSources/Sources/SIL/Test.swift

@@ -17,7 +17,7 @@
 //       }
 // - In SwiftCompilerSources/Sources/SIL/Test.swift's registerSILTests function,
 //   register the new test:
-//       registerFunctionTest(myNewTest, implementation: { myNewTest.run($0, $1, $2) })
+//       registerFunctionTest(myNewTest)
 //
 //===----------------------------------------------------------------------===//
 //
@@ -92,22 +92,21 @@
 import Basic
 import SILBridging
 
+/// The primary interface to in-IR tests.
 public struct FunctionTest {
-  public var name: String
-  public typealias FunctionTestImplementation = (Function, TestArguments, TestContext) -> ()
-  private var implementation: FunctionTestImplementation
-  init(name: String, implementation: @escaping FunctionTestImplementation) {
+  let name: String
+  let invocation: FunctionTestInvocation
+
+  public init(name: String, invocation: @escaping FunctionTestInvocation) {
     self.name = name
-    self.implementation = implementation
-  }
-  fileprivate func run(
-    _ function: BridgedFunction, 
-    _ arguments: BridgedTestArguments, 
-    _ test: BridgedTestContext) {
-    implementation(function.function, arguments.native, test.native)
+    self.invocation = invocation
   }
 }
 
+/// The type of the closure passed to a FunctionTest.
+public typealias FunctionTestInvocation = @convention(thin) (Function, TestArguments, TestContext) -> ()
+
+/// Wraps the arguments specified in the specify_test instruction.
 public struct TestArguments {
   public var bridged: BridgedTestArguments
   fileprivate init(bridged: BridgedTestArguments) {
@@ -130,6 +129,7 @@ extension BridgedTestArguments {
   public var native: TestArguments { TestArguments(bridged: self) }
 }
 
+/// An interface to the various analyses that are available.
 public struct TestContext {
   public var bridged: BridgedTestContext
   fileprivate init(bridged: BridgedTestContext) {
@@ -141,16 +141,52 @@ extension BridgedTestContext {
   public var native: TestContext { TestContext(bridged: self) }
 }
 
-private func registerFunctionTest(
-  _ test: FunctionTest,
-  implementation: BridgedFunctionTestThunk) {
+/// Registration of each test in the SIL module.
+public func registerSILTests() {
+  // Register each test.
+  registerFunctionTest(parseTestSpecificationTest)
+
+  // Finally register the thunk they all call through.
+  registerFunctionTestThunk(functionTestThunk)
+}
+
+
+private func registerFunctionTest(_ test: FunctionTest) {
   test.name._withStringRef { ref in
-    registerFunctionTest(ref, implementation)
+    registerFunctionTest(ref, eraseInvocation(test.invocation))
   }
 }
 
-public func registerSILTests() {
-  registerFunctionTest(parseTestSpecificationTest, implementation: { parseTestSpecificationTest.run($0, $1, $2) })
+/// The function called by the swift::test::FunctionTest which invokes the
+/// actual test function.
+///
+/// This function is necessary because tests need to be written in terms of
+/// native Swift types (Function, TestArguments, TestContext) rather than their
+/// bridged variants, but such a function isn't representable in C++.  This
+/// thunk unwraps the bridged types and invokes the real function.
+private func functionTestThunk(
+  _ erasedInvocation: UnsafeMutableRawPointer,
+  _ function: BridgedFunction, 
+  _ arguments: BridgedTestArguments, 
+  _ context: BridgedTestContext) {
+  let invocation = uneraseInvocation(erasedInvocation)
+  invocation(function.function, arguments.native, context.native)
+}
+
+/// Bitcast a thin test closure to void *.
+///
+/// Needed so that the closure can be represented in C++ for storage in the test
+/// registry.
+private func eraseInvocation(_ invocation: FunctionTestInvocation) -> UnsafeMutableRawPointer {
+  return unsafeBitCast(invocation, to: UnsafeMutableRawPointer.self)
+}
+
+/// Bitcast a void * to a thin test closure.
+///
+/// Needed so that the closure stored in the C++ test registry can be invoked
+/// via the functionTestThunk.
+private func uneraseInvocation(_ erasedInvocation: UnsafeMutableRawPointer) -> FunctionTestInvocation {
+  return unsafeBitCast(erasedInvocation, to: FunctionTestInvocation.self)
 }
 
 // Arguments:

include/swift/SIL/SILBridging.h

@@ -1622,6 +1622,10 @@ struct Arguments;
 class FunctionTest;
 } // namespace swift::test
 
+struct BridgedFunctionTest {
+  swift::test::FunctionTest *_Nonnull test;
+};
+
 struct BridgedTestArguments {
   swift::test::Arguments *_Nonnull arguments;
 
@@ -1657,10 +1661,15 @@ struct BridgedTestContext {
   swift::SwiftPassInvocation *_Nonnull invocation;
 };
 
-typedef void (*_Nonnull BridgedFunctionTestThunk)(BridgedFunction,
-                                                  BridgedTestArguments,
-                                                  BridgedTestContext);
-void registerFunctionTest(llvm::StringRef, BridgedFunctionTestThunk thunk);
+using SwiftNativeFunctionTestThunk = void (*_Nonnull)(void *_Nonnull,
+                                                      BridgedFunction,
+                                                      BridgedTestArguments,
+                                                      BridgedTestContext);
+
+void registerFunctionTestThunk(SwiftNativeFunctionTestThunk);
+
+void registerFunctionTest(llvm::StringRef,
+                          void *_Nonnull nativeSwiftInvocation);
 
 SWIFT_END_NULLABILITY_ANNOTATIONS
 

include/swift/SIL/Test.h

@@ -131,12 +131,11 @@ class FunctionTest final {
   ///                    values such as the results of analyses
   using Invocation = void (*)(SILFunction &, Arguments &, FunctionTest &);
 
-  using InvocationWithContext = void (*)(SILFunction &, Arguments &,
-                                         FunctionTest &, void *);
+  using NativeSwiftInvocation = void *;
 
 private:
   /// The lambda to be run.
-  TaggedUnion<Invocation, std::pair<InvocationWithContext, void *>> invocation;
+  TaggedUnion<Invocation, NativeSwiftInvocation> invocation;
 
 public:
   /// Creates a test that will run \p invocation and stores it in the global
@@ -152,7 +151,7 @@ class FunctionTest final {
   ///     } // end namespace swift::test
   FunctionTest(StringRef name, Invocation invocation);
 
-  FunctionTest(StringRef name, void *context, InvocationWithContext invocation);
+  FunctionTest(StringRef name, NativeSwiftInvocation invocation);
 
   /// Computes and returns the function's dominance tree.
   DominanceInfo *getDominanceInfo();

lib/SIL/Utils/SILBridging.cpp

@@ -133,14 +133,8 @@ void registerBridgedClass(StringRef className, SwiftMetatype metatype) {
 //                                Test
 //===----------------------------------------------------------------------===//
 
-void registerFunctionTest(llvm::StringRef name,
-                          BridgedFunctionTestThunk thunk) {
-  new swift::test::FunctionTest(
-      name, reinterpret_cast<void *>(thunk),
-      [](auto &function, auto &args, auto &test, void *ctx) {
-        auto thunk = reinterpret_cast<BridgedFunctionTestThunk>(ctx);
-        thunk({&function}, {&args}, test.getContext());
-      });
+void registerFunctionTest(llvm::StringRef name, void *nativeSwiftInvocation) {
+  new swift::test::FunctionTest(name, nativeSwiftInvocation);
 }
 
 bool BridgedTestArguments::hasUntaken() const {

lib/SIL/Utils/Test.cpp

@@ -26,6 +26,7 @@ namespace {
 
 class Registry {
   DenseMap<StringRef, FunctionTest *> registeredTests;
+  SwiftNativeFunctionTestThunk thunk;
 
 public:
   static Registry &get() {
@@ -39,6 +40,12 @@ class Registry {
     (void)inserted;
   }
 
+  void registerFunctionTestThunk(SwiftNativeFunctionTestThunk thunk) {
+    this->thunk = thunk;
+  }
+
+  SwiftNativeFunctionTestThunk getFunctionTestThunk() { return thunk; }
+
   FunctionTest *getFunctionTest(StringRef name) {
     auto *res = registeredTests[name];
     if (!res) {
@@ -62,15 +69,18 @@ class Registry {
 
 } // end anonymous namespace
 
+void registerFunctionTestThunk(SwiftNativeFunctionTestThunk thunk) {
+  Registry::get().registerFunctionTestThunk(thunk);
+}
+
 FunctionTest::FunctionTest(StringRef name, Invocation invocation)
     : invocation(invocation), pass(nullptr), function(nullptr),
       dependencies(nullptr) {
   Registry::get().registerFunctionTest(this, name);
 }
-FunctionTest::FunctionTest(StringRef name, void *context,
-                           InvocationWithContext invocation)
-    : invocation(std::make_pair(invocation, context)), pass(nullptr),
-      function(nullptr), dependencies(nullptr) {
+FunctionTest::FunctionTest(StringRef name, NativeSwiftInvocation invocation)
+    : invocation(invocation), pass(nullptr), function(nullptr),
+      dependencies(nullptr) {
   Registry::get().registerFunctionTest(this, name);
 }
 
@@ -84,11 +94,12 @@ void FunctionTest::run(SILFunction &function, Arguments &arguments,
   this->function = &function;
   this->dependencies = &dependencies;
   if (invocation.isa<Invocation>()) {
-    auto fn = this->invocation.get<Invocation>();
+    auto fn = invocation.get<Invocation>();
     fn(function, arguments, *this);
   } else {
-    auto pair = invocation.get<std::pair<InvocationWithContext, void *>>();
-    pair.first(function, arguments, *this, pair.second);
+    auto *fn = invocation.get<NativeSwiftInvocation>();
+    Registry::get().getFunctionTestThunk()(fn, {&function}, {&arguments},
+                                           getContext());
   }
   this->pass = nullptr;
   this->function = nullptr;