[Dependency Scanning] Add a C++ itnerface for a tool that answers dependency-scanning queries.

Author: artemcm

include/swift/SwiftScan/DependencyScanningTool.h

@@ -0,0 +1,55 @@
+//===-------------- DependencyScanningTool.h - Swift Compiler -------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_DEPENDENCY_SCANNING_TOOL_H
+#define SWIFT_DEPENDENCY_SCANNING_TOOL_H
+
+#include "swift/AST/ModuleDependencies.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/StringSaver.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace swift {
+namespace dependencies {
+
+/// The high-level implementation of the dependency scanner that runs on
+/// an individual worker thread.
+class DependencyScanningTool {
+public:
+  /// Construct a dependency scanning tool.
+  DependencyScanningTool();
+
+  /// Collect the full module depenedency graph for the input, ignoring any placeholder
+  /// modules.
+  ///
+  /// \returns a \c StringError with the diagnostic output if clang errors
+  /// occurred, \c FullDependencies otherwise.
+  std::string
+  getFullDependencies(ArrayRef<const char *> Command,
+                      const llvm::StringSet<> &InputFiles,
+                      const llvm::StringSet<> &PlaceholderModules);
+
+private:
+  /// Shared cache of module dependencies, re-used by individual queries
+  /// during the lifetime of this Tool
+  ModuleDependenciesCache GlobalCache;
+  
+  llvm::BumpPtrAllocator Alloc;
+  llvm::StringSaver Saver;
+};
+
+} // end namespace dependencies
+} // end namespace swift
+
+#endif // SWIFT_DEPENDENCY_SCANNING_TOOL_H

lib/FrontendTool/ScanDependencies.h renamed to include/swift/SwiftScan/ScanDependencies.h

@@ -24,8 +24,13 @@ class CompilerInstance;
 bool batchScanModuleDependencies(CompilerInstance &instance,
                                  llvm::StringRef batchInputFile);
 
+/// Scans the dependencies of the main module of \c instance and writes out
+/// the result in JSON
+bool scanAndOutputDependencies(CompilerInstance &instance);
+
 /// Scans the dependencies of the main module of \c instance.
-bool scanDependencies(CompilerInstance &instance);
+bool scanDependencies(CompilerInstance &instance,
+                      llvm::raw_ostream &out);
 
 /// Scans the dependencies of the underlying clang module of the main module
 /// of \c instance.

lib/CMakeLists.txt

@@ -36,6 +36,7 @@ add_subdirectory(PrintAsObjC)
 add_subdirectory(RemoteAST)
 add_subdirectory(Sema)
 add_subdirectory(Serialization)
+add_subdirectory(SwiftScan)
 add_subdirectory(SwiftDemangle)
 add_subdirectory(SwiftReflection)
 add_subdirectory(SwiftRemoteMirror)

lib/FrontendTool/CMakeLists.txt

@@ -8,13 +8,16 @@ add_swift_host_library(swiftFrontendTool STATIC
   TBD.cpp)
 add_dependencies(swiftFrontendTool
   swift-syntax-generated-headers
+  SwiftScanTool
   SwiftOptions)
 target_link_libraries(swiftFrontendTool INTERFACE
   clangAPINotes
+  SwiftScanTool
   clangBasic)
 target_link_libraries(swiftFrontendTool PRIVATE
     swiftClangImporter
     swiftDemangling
+    SwiftScanTool
     swiftFrontend
     swiftIDE
     swiftImmediate

lib/FrontendTool/FrontendTool.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -21,8 +21,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/FrontendTool/FrontendTool.h"
-#include "Dependencies.h"
-#include "ScanDependencies.h"
+#include "swift/SwiftScan/ScanDependencies.h"
+#include "ImportedModules.h"
 #include "TBD.h"
 #include "swift/Subsystems.h"
 #include "swift/AST/DiagnosticsFrontend.h"
@@ -1135,7 +1135,7 @@ static bool performScanDependencies(CompilerInstance &Instance) {
   auto batchScanInput =
       Instance.getASTContext().SearchPathOpts.BatchScanInputFilePath;
   if (batchScanInput.empty()) {
-    return scanDependencies(Instance);
+    return scanAndOutputDependencies(Instance);
   } else {
     return batchScanModuleDependencies(Instance, batchScanInput);
   }

lib/SwiftScan/CMakeLists.txt

@@ -0,0 +1,27 @@
+set_swift_llvm_is_available()
+add_swift_host_library(SwiftScanTool STATIC
+  DependencyScanningTool.cpp
+  ScanDependencies.cpp)
+add_dependencies(SwiftScanTool
+  swift-syntax-generated-headers
+  SwiftOptions)
+
+target_link_libraries(SwiftScanTool INTERFACE
+  clangAPINotes
+  clangBasic)
+
+target_link_libraries(SwiftScanTool PRIVATE
+    swiftClangImporter
+    swiftDemangling
+    swiftFrontend
+    swiftIDE
+    swiftImmediate
+    swiftIndex
+    swiftIRGen
+    swiftOption
+    swiftPrintAsObjC
+    swiftSerialization
+    swiftSIL
+    swiftSILGen
+    swiftSILOptimizer
+    swiftTBDGen)

lib/SwiftScan/DependencyScanningTool.cpp

@@ -0,0 +1,76 @@
+//===------------ DependencyScanningTool.cpp - Swift Compiler -------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/SwiftScan/DependencyScanningTool.h"
+#include "swift/SwiftScan/ScanDependencies.h"
+#include "swift/AST/DiagnosticEngine.h"
+#include "swift/AST/DiagnosticsFrontend.h"
+#include "swift/Basic/LLVMInitialize.h"
+#include "swift/Frontend/PrintingDiagnosticConsumer.h"
+#include "swift/Frontend/Frontend.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileSystem.h"
+
+#include <sstream>
+
+namespace swift {
+namespace dependencies {
+
+DependencyScanningTool::DependencyScanningTool()
+: GlobalCache(), Alloc(), Saver(Alloc) {
+  
+
+}
+
+std::string
+DependencyScanningTool::getFullDependencies(ArrayRef<const char *> Command,
+                                            const llvm::StringSet<> &InputFiles,
+                                            const llvm::StringSet<> &PlaceholderModules) {
+  PrintingDiagnosticConsumer PDC;
+  // State unique to an individual scan
+  auto Instance = std::make_unique<CompilerInstance>();
+  Instance->addDiagnosticConsumer(&PDC);
+
+  // Basic error checking on the arguments
+  if (Command.empty()) {
+    Instance->getDiags().diagnose(SourceLoc(), diag::error_no_frontend_args);
+    return "Error";
+  }
+
+  CompilerInvocation Invocation;
+  SmallString<128> WorkingDirectory;
+  llvm::sys::fs::current_path(WorkingDirectory);
+
+  // Parse arguments.
+  std::string CommandString;
+  for (const auto *c : Command) {
+    CommandString.append(c);
+    CommandString.append(" ");
+  }
+  SmallVector<const char*, 4> Args;
+  llvm::cl::TokenizeGNUCommandLine(CommandString, Saver, Args);
+  if (Invocation.parseArgs(Args, Instance->getDiags())) {
+    return "Error";
+  }
+
+  // Setup the instance
+  Instance->setup(Invocation);
+
+  std::string JSONOutput;
+  llvm::raw_string_ostream Oss(JSONOutput);
+  scanDependencies(*Instance, Oss);
+  Oss.flush();
+  
+  return JSONOutput;
+}
+}
+}

lib/FrontendTool/ScanDependencies.cpp renamed to lib/SwiftScan/ScanDependencies.cpp

@@ -10,7 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "ScanDependencies.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticEngine.h"
@@ -27,6 +26,7 @@
 #include "swift/Frontend/FrontendOptions.h"
 #include "swift/Frontend/ModuleInterfaceLoader.h"
 #include "swift/Strings.h"
+#include "swift/SwiftScan/ScanDependencies.h"
 #include "clang/Basic/Module.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringMap.h"
@@ -794,12 +794,9 @@ bool swift::batchScanModuleDependencies(CompilerInstance &instance,
   return false;
 }
 
-bool swift::scanDependencies(CompilerInstance &instance) {
+bool swift::scanAndOutputDependencies(CompilerInstance &instance) {
   ASTContext &Context = instance.getASTContext();
-  ModuleDecl *mainModule = instance.getMainModule();
-  const CompilerInvocation &invocation = instance.getInvocation();
-  const FrontendOptions &opts = invocation.getFrontendOptions();
-
+  const FrontendOptions &opts = instance.getInvocation().getFrontendOptions();
   std::string path = opts.InputsAndOutputs.getSingleOutputFilename();
   std::error_code EC;
   llvm::raw_fd_ostream out(path, EC, llvm::sys::fs::F_None);
@@ -811,6 +808,17 @@ bool swift::scanDependencies(CompilerInstance &instance) {
     return true;
   }
 
+  // Execute scan, writing JSON output to the output stream
+  return scanDependencies(instance, out);
+}
+
+bool swift::scanDependencies(CompilerInstance &instance,
+                             llvm::raw_ostream &out) {
+  ASTContext &Context = instance.getASTContext();
+  ModuleDecl *mainModule = instance.getMainModule();
+  const CompilerInvocation &invocation = instance.getInvocation();
+  const FrontendOptions &opts = invocation.getFrontendOptions();
+
   // Main module file name.
   auto newExt = file_types::getExtension(file_types::TY_SwiftModuleFile);
   llvm::SmallString<32> mainModulePath = mainModule->getName().str();