Fix FunctionTest memory corruption in SwiftCompilerSouces.

A FunctionTest created in Swift source has no persistent storage
address. This results in sporadic crashes when running unit tests.

Fix the FunctionTest registry to store the value of the test.

Eventually, we could probably rig something up with @_rawLayout, but
it makes more sense for FunctionTest to be a value type anyway.

Author: atrick

include/swift/SIL/Test.h

@@ -120,6 +120,9 @@ class TestRunner;
 /// Tests are instantiated once at program launch.  At that time, they are
 /// stored in a registry name -> test.  When an specify_test instruction
 /// naming a particular test is processed, that test is run.
+///
+/// This is a value type because we have no persistent location in which to
+/// store SwiftCompilerSources tests.
 class FunctionTest final {
 public:
   /// Wraps a test lambda.
@@ -190,7 +193,7 @@ class FunctionTest final {
            SILFunctionTransform &pass, Dependencies &dependencies);
 
   /// Retrieve the test with named \p name from the global registry.
-  static FunctionTest *get(StringRef name);
+  static FunctionTest get(StringRef name);
 
   /// The instance of the TestRunner pass currently running this test.  Only
   /// non-null when FunctionTest::run is executing.

lib/SIL/Utils/Test.cpp

@@ -25,7 +25,7 @@ using namespace swift::test;
 namespace {
 
 class Registry {
-  StringMap<FunctionTest *> registeredTests;
+  StringMap<FunctionTest> registeredTests;
   SwiftNativeFunctionTestThunk thunk;
 
 public:
@@ -34,7 +34,7 @@ class Registry {
     return registry;
   }
 
-  void registerFunctionTest(FunctionTest *test, StringRef name) {
+  void registerFunctionTest(FunctionTest test, StringRef name) {
     auto inserted = registeredTests.insert({name, test}).second;
     assert(inserted);
     (void)inserted;
@@ -46,22 +46,21 @@ class Registry {
 
   SwiftNativeFunctionTestThunk getFunctionTestThunk() { return thunk; }
 
-  FunctionTest *getFunctionTest(StringRef name) {
-    // Avoid creating a new entry here.
-    auto *res = registeredTests.lookup(name);
-    if (!res) {
+  FunctionTest getFunctionTest(StringRef name) {
+    auto iter = registeredTests.find(name);
+    if (iter == registeredTests.end()) {
       llvm::errs() << "Found no test named " << name << "!\n";
       print(llvm::errs());
     }
-    return res;
+    return iter->getValue();
   }
 
   void print(raw_ostream &OS) const {
     OS << "test::Registry(" << this << ") with " << registeredTests.size()
        << " entries: {{\n";
     for (auto &stringMapEntry : registeredTests) {
       OS << "\t" << stringMapEntry.getKey() << " -> "
-         << stringMapEntry.getValue() << "\n";
+         << &stringMapEntry.getValue() << "\n";
     }
     OS << "}} test::Registry(" << this << ")\n";
   }
@@ -78,21 +77,18 @@ void registerFunctionTestThunk(SwiftNativeFunctionTestThunk thunk) {
 FunctionTest::FunctionTest(StringRef name, Invocation invocation)
     : invocation(invocation), pass(nullptr), function(nullptr),
       dependencies(nullptr) {
-  Registry::get().registerFunctionTest(this, name);
+  Registry::get().registerFunctionTest(*this, name);
 }
 FunctionTest::FunctionTest(StringRef name, NativeSwiftInvocation invocation)
     : invocation(invocation), pass(nullptr), function(nullptr),
       dependencies(nullptr) {}
 
 void FunctionTest::createNativeSwiftFunctionTest(
     StringRef name, NativeSwiftInvocation invocation) {
-  /// Statically allocate the tests to avoid triggering LSAN's "leak" detection.
-  static SmallVector<FunctionTest, 4> tests;
-  auto &test = tests.emplace_back(name, invocation);
-  Registry::get().registerFunctionTest(&test, name);
+  Registry::get().registerFunctionTest({name, invocation}, name);
 }
 
-FunctionTest *FunctionTest::get(StringRef name) {
+FunctionTest FunctionTest::get(StringRef name) {
   return Registry::get().getFunctionTest(name);
 }
 

lib/SILOptimizer/UtilityPasses/TestRunner.cpp

@@ -98,14 +98,10 @@ void TestRunner::printTestLifetime(bool begin, unsigned testIndex,
 }
 
 void TestRunner::runTest(StringRef name, Arguments &arguments) {
-  auto *test = FunctionTest::get(name);
-  if (!test) {
-    llvm::outs() << "No test named: " << name << "\n";
-    assert(false && "Invalid test name");
-  }
+  FunctionTest test = FunctionTest::get(name);
   auto *function = getFunction();
   FunctionTestDependenciesImpl dependencies(this, function);
-  test->run(*function, arguments, *this, dependencies);
+  test.run(*function, arguments, *this, dependencies);
 }
 
 void TestRunner::run() {