[Macros] Emit loaded module trace for plugins loaded from search paths

When loading plugins from `-plugin-path`, use the global `PluginRegistry` to keep a record of what's loaded. Emit these dependencies to the loaded module trace.

Author: rxwei

include/swift/AST/PluginRegistry.h

@@ -78,7 +78,7 @@ class PluginRegistry {
       LoadedPluginExecutables;
 
 public:
-  llvm::Error loadLibraryPlugin(llvm::StringRef path);
+  llvm::Expected<void *> loadLibraryPlugin(llvm::StringRef path);
   llvm::Expected<LoadedExecutablePlugin *>
   loadExecutablePlugin(llvm::StringRef path);
 

lib/AST/ASTContext.cpp

@@ -6241,9 +6241,10 @@ void ASTContext::loadCompilerPlugins() {
                      err.message());
       continue;
     }
-    if (auto error = getPluginRegistry()->loadLibraryPlugin(resolvedPath)) {
+    auto loaded = getPluginRegistry()->loadLibraryPlugin(resolvedPath);
+    if (!loaded) {
       Diags.diagnose(SourceLoc(), diag::compiler_plugin_not_loaded, path,
-                     llvm::toString(std::move(error)));
+                     llvm::toString(loaded.takeError()));
     }
   }
 

lib/AST/PluginRegistry.cpp

@@ -43,10 +43,11 @@ extern "C" void swift_ASTGen_destroyCompilerPluginCapability(void *value);
 
 using namespace swift;
 
-llvm::Error PluginRegistry::loadLibraryPlugin(StringRef path) {
-  if (LoadedPluginLibraries.find(path) != LoadedPluginLibraries.end()) {
+llvm::Expected<void *> PluginRegistry::loadLibraryPlugin(StringRef path) {
+  auto found = LoadedPluginLibraries.find(path);
+  if (found != LoadedPluginLibraries.end()) {
     // Already loaded.
-    return llvm::Error::success();
+    return found->second;
   }
   void *lib = nullptr;
 #if defined(_WIN32)
@@ -62,7 +63,7 @@ llvm::Error PluginRegistry::loadLibraryPlugin(StringRef path) {
   }
 #endif
   LoadedPluginLibraries.insert({path, lib});
-  return llvm::Error::success();
+  return lib;
 }
 
 llvm::Expected<LoadedExecutablePlugin *>

lib/FrontendTool/LoadedModuleTrace.cpp

@@ -15,6 +15,7 @@
 #include "swift/AST/DiagnosticEngine.h"
 #include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/AST/Module.h"
+#include "swift/AST/PluginRegistry.h"
 #include "swift/Basic/FileTypes.h"
 #include "swift/Basic/JSONSerialization.h"
 #include "swift/Frontend/FrontendOptions.h"
@@ -764,6 +765,11 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
         std::make_pair(loadedDecl->getModuleFilename(), loadedDecl));
   }
 
+  // Add compiler plugin libraries as dependencies.
+  auto *pluginRegistry = ctxt.getPluginRegistry();
+  for (auto &pluginEntry : pluginRegistry->getLoadedLibraryPlugins())
+    depTracker->addDependency(pluginEntry.getKey(), /*IsSystem*/ false);
+
   std::vector<SwiftModuleTraceInfo> swiftModules;
   computeSwiftModuleTraceInfo(ctxt, abiDependencies, pathToModuleDecl,
                               *depTracker, opts.PrebuiltModuleCachePath,

lib/Sema/TypeCheckMacros.cpp

@@ -304,26 +304,26 @@ MacroDefinition MacroDefinitionRequest::evaluate(
 }
 
 /// Load a plugin library based on a module name.
-static void *loadPluginByName(StringRef searchPath, StringRef moduleName, llvm::vfs::FileSystem &fs) {
+static void *loadPluginByName(StringRef searchPath,
+                              StringRef moduleName,
+                              llvm::vfs::FileSystem &fs,
+                              PluginRegistry *registry) {
   SmallString<128> fullPath(searchPath);
   llvm::sys::path::append(fullPath, "lib" + moduleName + LTDL_SHLIB_EXT);
   if (fs.getRealPath(fullPath, fullPath))
     return nullptr;
-
-#if defined(_WIN32)
-  return LoadLibraryA(fullPath.c_str());
-#else
-  return dlopen(fullPath.c_str(), RTLD_LAZY);
-#endif
+  auto loadResult = registry->loadLibraryPlugin(fullPath);
+  return loadResult ? *loadResult : nullptr;
 }
 
 void *CompilerPluginLoadRequest::evaluate(
     Evaluator &evaluator, ASTContext *ctx, Identifier moduleName
 ) const {
   auto fs = ctx->SourceMgr.getFileSystem();
   auto &searchPathOpts = ctx->SearchPathOpts;
+  auto *registry = ctx->getPluginRegistry();
   for (const auto &path : searchPathOpts.PluginSearchPaths) {
-    if (auto found = loadPluginByName(path, moduleName.str(), *fs))
+    if (auto found = loadPluginByName(path, moduleName.str(), *fs, registry))
       return found;
   }
 

test/Macros/macro_expand.swift

@@ -5,8 +5,6 @@
 // Diagnostics testing
 // RUN: %target-typecheck-verify-swift -swift-version 5 -enable-experimental-feature FreestandingMacros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS
 
-// RUN: %target-typecheck-verify-swift -swift-version 5 -enable-experimental-feature FreestandingMacros -plugin-path %t -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS
-
 // RUN: not %target-swift-frontend -swift-version 5 -typecheck -enable-experimental-feature FreestandingMacros -load-plugin-library %t/%target-library-name(MacroDefinition) -I %swift-host-lib-dir -module-name MacroUser -DTEST_DIAGNOSTICS -serialize-diagnostics-path %t/macro_expand.dia %s -emit-macro-expansion-files no-diagnostics > %t/macro-printing.txt
 // RUN: c-index-test -read-diagnostics %t/macro_expand.dia 2>&1 | %FileCheck -check-prefix CHECK-DIAGS %s
 
@@ -23,6 +21,12 @@
 // RUN: %target-run %t/main | %FileCheck %s
 // REQUIRES: executable_test
 
+// Plugin search path and loaded module trace testing
+// RUN: %target-swift-frontend -swift-version 5 -emit-sil -enable-experimental-feature FreestandingMacros -plugin-path %t -I %swift-host-lib-dir %s -module-name MacroUser -emit-loaded-module-trace -o %t/loaded_module_trace
+// RUN: %FileCheck -check-prefix=CHECK-MODULE-TRACE %s < %t/loaded_module_trace.trace.json
+
+// CHECK-MODULE-TRACE: {{libMacroDefinition.dylib|libMacroDefinition.so|MacroDefinition.dll}}
+
 // FIXME: Swift parser is not enabled on Linux CI yet.
 // REQUIRES: OS=macosx