Frontend: when emitting loaded module trace file, also emit a JSON file tracking Objc method calls issued from the source code

lib/FrontendTool/Dependencies.h

@@ -32,6 +32,9 @@ bool emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
                                    const FrontendOptions &opts,
                                    const InputFile &input);
 
+bool emitObjCMessageSendTraceIfNeeded(ModuleDecl *mainModule,
+                                      const FrontendOptions &opts);
+
 } // end namespace swift
 
 #endif

lib/FrontendTool/FrontendTool.cpp

@@ -1001,6 +1001,7 @@ static void performEndOfPipelineActions(CompilerInstance &Instance) {
         Instance.getMainModule(), Instance.getDependencyTracker(), opts);
 
     dumpAPIIfNeeded(Instance);
+    swift::emitObjCMessageSendTraceIfNeeded(Instance.getMainModule(), opts);
   }
 
   // Contains the hadError checks internally, we still want to output the

lib/FrontendTool/LoadedModuleTrace.cpp

@@ -17,12 +17,15 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/ModuleLoader.h"
 #include "swift/AST/PluginRegistry.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/FileTypes.h"
 #include "swift/Basic/JSONSerialization.h"
 #include "swift/Frontend/FrontendOptions.h"
+#include "swift/IDE/SourceEntityWalker.h"
 
 #include "clang/Basic/Module.h"
+#include "clang/AST/DeclObjC.h"
 
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
@@ -810,3 +813,69 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
   }
   return false;
 }
+
+
+bool swift::emitObjCMessageSendTraceIfNeeded(ModuleDecl *mainModule,
+                                             const FrontendOptions &opts) {
+  ASTContext &ctxt = mainModule->getASTContext();
+  assert(!ctxt.hadError() &&
+         "We should've already exited earlier if there was an error.");
+  class ObjcMethodRefereceCollector: public SourceEntityWalker {
+    std::set<const clang::ObjCMethodDecl*> results;
+    bool visitDeclReference(ValueDecl *D, CharSourceRange Range,
+                            TypeDecl *CtorTyRef, ExtensionDecl *ExtTyRef,
+                            Type T, ReferenceMetaData Data) override {
+      if (!Range.isValid())
+        return true;
+      if (auto *clangD = dyn_cast_or_null<clang::ObjCMethodDecl>(D->getClangDecl())) {
+        results.insert(clangD);
+      }
+      return true;
+    }
+  public:
+    void dump(llvm::raw_ostream &OS) {
+      OS << "[\n";
+      for (const clang::ObjCMethodDecl* clangD: results) {
+        auto &SM = clangD->getASTContext().getSourceManager();
+        clang::SourceLocation Loc = clangD->getLocation();
+        if (!Loc.isValid()) {
+          continue;
+        }
+        OS << "\t{\n";
+        OS << "\t\t\"method_name\": \"" << clangD->getNameAsString() << "\",\n";
+        OS << "\t\t\"location\": \"" << Loc.printToString(SM) << "\"\n";
+        OS << "\t}";
+        OS << ",\n";
+      }
+      OS << "{} ]\n";
+    }
+  };
+  opts.InputsAndOutputs.forEachInput([&](const InputFile &input) {
+    auto loadedModuleTracePath = input.getLoadedModuleTracePath();
+    if (loadedModuleTracePath.empty())
+      return false;
+    llvm::SmallString<128> tracePath {loadedModuleTracePath};
+    llvm::sys::path::remove_filename(tracePath);
+    llvm::sys::path::append(tracePath, "SWIFT_OBJC_MESSAGE_TRACE");
+    if (!llvm::sys::fs::exists(tracePath)) {
+      if (llvm::sys::fs::create_directory(tracePath))
+        return false;
+    }
+    llvm::sys::path::append(tracePath, "%%%%-%%%%-%%%%.json");
+    int tmpFD;
+    if (llvm::sys::fs::createUniqueFile(tracePath.str(), tmpFD, tracePath)) {
+      return false;
+    }
+    // Write the contents of the buffer.
+    llvm::raw_fd_ostream out(tmpFD, /*shouldClose=*/true);
+    ObjcMethodRefereceCollector collector;
+    for (auto *FU : mainModule->getFiles()) {
+      if (auto *SF = dyn_cast<SourceFile>(FU)) {
+        collector.walk(*SF);
+      }
+    }
+    collector.dump(out);
+    return true;
+  });
+  return false;
+}

test/IDE/Inputs/print_first_file_under_directory.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+#
+# Usage: print_first_file_under_director.py /dir/
+
+import os
+import sys
+
+directory = sys.argv[1]
+
+for p in os.listdir(directory):
+    with open(directory + '/' + p, 'r') as f:
+        print(f.read())
+    exit(0)
+
+exit(1)

test/IDE/objc_send_collector.swift

@@ -0,0 +1,20 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend  -I %t/lib/swift -typecheck %s -module-name main -swift-version 5 -F %S/Inputs/mock-sdk -emit-loaded-module-trace-path %t/.MODULE_TRACE
+// RUN: %{python} %S/Inputs/print_first_file_under_directory.py %t/SWIFT_OBJC_MESSAGE_TRACE | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+// EXPECTED OUTPUT STARTS BELOW THIS LINE.
+
+
+import Foo
+
+public func testProperties(_ x: FooClassBase) {
+  _ = x.fooBaseInstanceFunc0()
+  x.fooBaseInstanceFunc1(1.2)
+}
+
+// CHECK: fooBaseInstanceFunc0
+// CHECK: fooBaseInstanceFunc1
+// CHECK: SOURCE_DIR/test/IDE/Inputs/mock-sdk/Foo.framework/Headers/Foo.h