[CodeCompletion] Give up fast-completion if dependent files are modified

Check if dependencies are modified since the last checking.
Dependencies:

 - Other source files in the current module
 - Dependent files collected by the dependency tracker

When:

 - If the last dependency check was over N (defaults to 5) seconds ago

Invalidate if:

 - The dependency file is missing
 - The modification time of the dependecy is greater than the last check
 - If the modification time is zero, compare the content using the file
   system from the previous completion and the current completion

rdar://problem/62336432

include/swift/IDE/CompletionInstance.h

@@ -18,6 +18,7 @@
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Chrono.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/VirtualFileSystem.h"
 
@@ -38,13 +39,20 @@ makeCodeCompletionMemoryBuffer(const llvm::MemoryBuffer *origBuf,
 /// Manages \c CompilerInstance for completion like operations.
 class CompletionInstance {
   unsigned MaxASTReuseCount = 100;
+  unsigned DependencyCheckIntervalSecond = 5;
 
   std::mutex mtx;
 
   std::unique_ptr<CompilerInstance> CachedCI;
   llvm::hash_code CachedArgHash;
+  llvm::sys::TimePoint<> DependencyCheckedTimestamp;
   unsigned CachedReuseCount = 0;
 
+  void cacheCompilerInstance(std::unique_ptr<CompilerInstance> CI,
+                             llvm::hash_code ArgsHash);
+
+  bool shouldCheckDependencies() const;
+
   /// Calls \p Callback with cached \c CompilerInstance if it's usable for the
   /// specified completion request.
   /// Returns \c if the callback was called. Returns \c false if the compiler
@@ -52,6 +60,7 @@ class CompletionInstance {
   /// in function bodies, or the interface hash of the file has changed.
   bool performCachedOperationIfPossible(
       const swift::CompilerInvocation &Invocation, llvm::hash_code ArgsHash,
+      llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
       llvm::MemoryBuffer *completionBuffer, unsigned int Offset,
       DiagnosticConsumer *DiagC,
       llvm::function_ref<void(CompilerInstance &, bool)> Callback);
@@ -69,6 +78,8 @@ class CompletionInstance {
       llvm::function_ref<void(CompilerInstance &, bool)> Callback);
 
 public:
+  void setDependencyCheckIntervalSecond(unsigned Value);
+
   /// Calls \p Callback with a \c CompilerInstance which is prepared for the
   /// second pass. \p Callback is resposible to perform the second pass on it.
   /// The \c CompilerInstance may be reused from the previous completions,

lib/IDE/CompletionInstance.cpp

@@ -18,6 +18,8 @@
 #include "swift/AST/Module.h"
 #include "swift/AST/PrettyStackTrace.h"
 #include "swift/AST/SourceFile.h"
+#include "swift/Serialization/SerializedModuleLoader.h"
+#include "swift/ClangImporter/ClangModule.h"
 #include "swift/Basic/LangOptions.h"
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/SourceManager.h"
@@ -28,6 +30,7 @@
 #include "swift/Subsystems.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "clang/AST/ASTContext.h"
 
 using namespace swift;
 using namespace ide;
@@ -162,10 +165,77 @@ static DeclContext *getEquivalentDeclContextFromSourceFile(DeclContext *DC,
   return newDC;
 }
 
+/// Check if any dependent files are modified since \p timestamp.
+bool areAnyDependentFilesInvalidated(CompilerInstance &CI,
+                                     llvm::vfs::FileSystem &FS,
+                                     StringRef currentFileName,
+                                     llvm::sys::TimePoint<> timestamp) {
+
+  auto isInvalidated = [&](StringRef filePath) -> bool {
+    auto stat = FS.status(filePath);
+    if (!stat)
+      // Missing.
+      return true;
+
+    auto lastModTime = stat->getLastModificationTime();
+    if (lastModTime > timestamp)
+      // Modified.
+      return true;
+
+    // If the last modification time is zero, this file is probably from a
+    // virtual file system. We need to check the content.
+    if (lastModTime == llvm::sys::TimePoint<>()) {
+      if (&CI.getFileSystem() == &FS)
+        return false;
+
+      auto oldContent = CI.getFileSystem().getBufferForFile(filePath);
+      auto newContent = FS.getBufferForFile(filePath);
+      if (!oldContent || !newContent)
+        // (unreachable?)
+        return true;
+
+      if (oldContent.get()->getBuffer() != newContent.get()->getBuffer())
+        // Different content.
+        return true;
+    }
+
+    return false;
+  };
+
+  // Check files in the current module.
+  for (FileUnit *file : CI.getMainModule()->getFiles()) {
+    StringRef filename;
+    if (auto SF = dyn_cast<SourceFile>(file))
+      filename = SF->getFilename();
+    else if (auto LF = dyn_cast<LoadedFile>(file))
+      filename = LF->getFilename();
+    else
+      continue;
+
+    // Ignore the current file and synthesized files.
+    if (filename.empty() || filename.front() == '<' ||
+        filename.equals(currentFileName))
+      continue;
+
+    if (isInvalidated(filename))
+      return true;
+  }
+
+  // Check other non-system depenencies (e.g. modules, headers).
+  for (auto &dep : CI.getDependencyTracker()->getDependencies()) {
+    if (isInvalidated(dep))
+      return true;
+  }
+
+  // All loaded module files are not modified since the timestamp.
+  return false;
+}
+
 } // namespace
 
 bool CompletionInstance::performCachedOperationIfPossible(
     const swift::CompilerInvocation &Invocation, llvm::hash_code ArgsHash,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
     llvm::MemoryBuffer *completionBuffer, unsigned int Offset,
     DiagnosticConsumer *DiagC,
     llvm::function_ref<void(CompilerInstance &, bool)> Callback) {
@@ -187,10 +257,17 @@ bool CompletionInstance::performCachedOperationIfPossible(
   auto &oldInfo = oldState->getCodeCompletionDelayedDeclState();
 
   auto &SM = CI.getSourceMgr();
-  if (SM.getIdentifierForBuffer(SM.getCodeCompletionBufferID()) !=
+  auto bufferName = completionBuffer->getBufferIdentifier();
-      completionBuffer->getBufferIdentifier())
+  if (SM.getIdentifierForBuffer(SM.getCodeCompletionBufferID()) != bufferName)
     return false;
 
+  if (shouldCheckDependencies()) {
+    if (areAnyDependentFilesInvalidated(CI, *FileSystem, bufferName,
+                                        DependencyCheckedTimestamp))
+      return false;
+    DependencyCheckedTimestamp = std::chrono::system_clock::now();
+  }
+
   // Parse the new buffer into temporary SourceFile.
   SourceManager tmpSM;
   auto tmpBufferID = tmpSM.addMemBufferCopy(completionBuffer);
@@ -263,8 +340,7 @@ bool CompletionInstance::performCachedOperationIfPossible(
         completionBuffer->getBuffer().slice(startOffset, endOffset);
     auto newOffset = Offset - startOffset;
 
-    newBufferID = SM.addMemBufferCopy(sourceText,
+    newBufferID = SM.addMemBufferCopy(sourceText, bufferName);
-                                      completionBuffer->getBufferIdentifier());
     SM.openVirtualFile(SM.getLocForBufferStart(newBufferID),
                        tmpSM.getDisplayNameForLoc(startLoc),
                        tmpSM.getLineAndColumn(startLoc).first - 1);
@@ -310,8 +386,7 @@ bool CompletionInstance::performCachedOperationIfPossible(
       endOffset = tmpSM.getLocOffsetInBuffer(endLoc, tmpBufferID);
       sourceText = sourceText.slice(0, endOffset);
     }
-    newBufferID = SM.addMemBufferCopy(sourceText,
+    newBufferID = SM.addMemBufferCopy(sourceText, bufferName);
-                                      completionBuffer->getBufferIdentifier());
     SM.setCodeCompletionPoint(newBufferID, Offset);
 
     // Create a new module and a source file using the current AST context.
@@ -369,7 +444,15 @@ bool CompletionInstance::performNewOperation(
     llvm::function_ref<void(CompilerInstance &, bool)> Callback) {
   llvm::PrettyStackTraceString trace("While performing new completion");
 
+  auto isCachedCompletionRequested = ArgsHash.hasValue();
+
   auto TheInstance = std::make_unique<CompilerInstance>();
+
+  // Track dependencies in fast-completion mode to invalidate the compiler
+  // instance if any dependent files are modified.
+  if (isCachedCompletionRequested)
+    TheInstance->createDependencyTracker(false);
+
   {
     auto &CI = *TheInstance;
     if (DiagC)
@@ -407,15 +490,34 @@ bool CompletionInstance::performNewOperation(
     Callback(CI, /*reusingASTContext=*/false);
   }
 
-  if (ArgsHash.hasValue()) {
+  // Cache the compiler instance if fast completion is enabled.
-    CachedCI = std::move(TheInstance);
+  if (isCachedCompletionRequested)
-    CachedArgHash = *ArgsHash;
+    cacheCompilerInstance(std::move(TheInstance), *ArgsHash);
-    CachedReuseCount = 0;
-  }
 
   return true;
 }
 
+void CompletionInstance::cacheCompilerInstance(
+    std::unique_ptr<CompilerInstance> CI, llvm::hash_code ArgsHash) {
+  CachedCI = std::move(CI);
+  CachedArgHash = ArgsHash;
+  auto now = std::chrono::system_clock::now();
+  DependencyCheckedTimestamp = now;
+  CachedReuseCount = 0;
+}
+
+bool CompletionInstance::shouldCheckDependencies() const {
+  assert(CachedCI);
+  using namespace std::chrono;
+  auto now = system_clock::now();
+  return DependencyCheckedTimestamp + seconds(DependencyCheckIntervalSecond) < now;
+}
+
+void CompletionInstance::setDependencyCheckIntervalSecond(unsigned Value) {
+  std::lock_guard<std::mutex> lock(mtx);
+  DependencyCheckIntervalSecond = Value;
+}
+
 bool swift::ide::CompletionInstance::performOperation(
     swift::CompilerInvocation &Invocation, llvm::ArrayRef<const char *> Args,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
@@ -451,8 +553,9 @@ bool swift::ide::CompletionInstance::performOperation(
     // the cached completion instance.
     std::lock_guard<std::mutex> lock(mtx);
 
-    if (performCachedOperationIfPossible(Invocation, ArgsHash, completionBuffer,
+    if (performCachedOperationIfPossible(Invocation, ArgsHash, FileSystem,
-                                         Offset, DiagC, Callback))
+                                         completionBuffer, Offset, DiagC,
+                                         Callback))
       return true;
 
     if (performNewOperation(ArgsHash, Invocation, FileSystem, completionBuffer,

test/SourceKit/CodeComplete/Inputs/checkdeps/ClangFW.framework/Headers/ClangFW.h

@@ -0,0 +1,2 @@
+
+#import <ClangFW/Funcs.h>

test/SourceKit/CodeComplete/Inputs/checkdeps/ClangFW.framework/Headers/Funcs.h

@@ -0,0 +1,4 @@
+#ifndef CLANGFW_FUNCS_H
+#define CLANGFW_FUNCS_H
+int clangFWFunc();
+#endif

test/SourceKit/CodeComplete/Inputs/checkdeps/ClangFW.framework/Modules/module.modulemap

@@ -0,0 +1,4 @@
+framework module ClangFW {
+  umbrella header "ClangFW.h"
+  export *
+}

test/SourceKit/CodeComplete/Inputs/checkdeps/ClangFW.framework_mod/Headers/Funcs.h

@@ -0,0 +1,5 @@
+#ifndef CLANGFW_FUNCS_H
+#define CLANGFW_FUNCS_H
+int clangFWFunc_mod();
+#endif
+

test/SourceKit/CodeComplete/Inputs/checkdeps/MyProject/Bridging.h

@@ -0,0 +1 @@
+#import "LocalCFunc.h"

test/SourceKit/CodeComplete/Inputs/checkdeps/MyProject/Library.swift

@@ -0,0 +1 @@
+func localSwiftFunc() -> Int {}

test/SourceKit/CodeComplete/Inputs/checkdeps/MyProject/LocalCFunc.h

@@ -0,0 +1,6 @@
+#ifndef MYPROJECT_LOCALCFUNC_H
+#define MYPROJECT_LOCALCFUNC_H
+
+int localClangFunc();
+
+#endif

test/SourceKit/CodeComplete/Inputs/checkdeps/MyProject_mod/Library.swift

@@ -0,0 +1 @@
+func localSwiftFunc_mod() -> Int {}

test/SourceKit/CodeComplete/Inputs/checkdeps/MyProject_mod/LocalCFunc.h

@@ -0,0 +1,7 @@
+#ifndef MYPROJECT_LOCALCFUNC_H
+#define MYPROJECT_LOCALCFUNC_H
+
+int localClangFunc_mod();
+
+#endif
+

test/SourceKit/CodeComplete/Inputs/checkdeps/SwiftFW_src/Funcs.swift

@@ -0,0 +1,2 @@
+public func swiftFWFunc() -> Int { return 1 }
+

test/SourceKit/CodeComplete/Inputs/checkdeps/SwiftFW_src_mod/Funcs.swift

@@ -0,0 +1 @@
+public func swiftFWFunc_mod() -> Int { return 1 }

test/SourceKit/CodeComplete/Inputs/checkdeps/test.swift

@@ -0,0 +1,5 @@
+import Foundation
+import ClangFW // < 500 headers framework
+func foo() {
+  /* HERE */
+}

test/SourceKit/CodeComplete/complete_checkdeps_bridged.swift

@@ -0,0 +1,72 @@
+import ClangFW
+import SwiftFW
+
+func foo() {
+  /*HERE*/
+}
+
+// RUN: %empty-directory(%t/Frameworks)
+// RUN: %empty-directory(%t/MyProject)
+
+// RUN: COMPILER_ARGS=( \
+// RUN:   -target %target-triple \
+// RUN:   -module-name MyProject \
+// RUN:   -F %t/Frameworks \
+// RUN:   -I %t/MyProject \
+// RUN:   -import-objc-header %t/MyProject/Bridging.h \
+// RUN:   %t/MyProject/Library.swift \
+// RUN:   %s \
+// RUN: )
+// RUN: INPUT_DIR=%S/Inputs/checkdeps
+// RUN: DEPCHECK_INTERVAL=1
+// RUN: SLEEP_TIME=2
+
+// RUN: cp -R $INPUT_DIR/MyProject %t/
+// RUN: cp -R $INPUT_DIR/ClangFW.framework %t/Frameworks/
+// RUN: %empty-directory(%t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule)
+// RUN: %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src/Funcs.swift
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=global-config -completion-check-dependency-interval ${DEPCHECK_INTERVAL} == \
+
+// RUN:   -shell -- echo "### Initial" == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Modify bridging header library file' == \
+// RUN:   -shell -- cp -R $INPUT_DIR/MyProject_mod/LocalCFunc.h %t/MyProject/ == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Fast completion' == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} \
+
+// RUN:   | %FileCheck %s
+
+
+// CHECK-LABEL: ### Initial
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Modify bridging header library file
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc_mod()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Fast completion
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc_mod()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK: key.reusingastcontext: 1

test/SourceKit/CodeComplete/complete_checkdeps_clangmodule.swift

@@ -0,0 +1,72 @@
+import ClangFW
+import SwiftFW
+
+func foo() {
+  /*HERE*/
+}
+
+// RUN: %empty-directory(%t/Frameworks)
+// RUN: %empty-directory(%t/MyProject)
+
+// RUN: COMPILER_ARGS=( \
+// RUN:   -target %target-triple \
+// RUN:   -module-name MyProject \
+// RUN:   -F %t/Frameworks \
+// RUN:   -I %t/MyProject \
+// RUN:   -import-objc-header %t/MyProject/Bridging.h \
+// RUN:   %t/MyProject/Library.swift \
+// RUN:   %s \
+// RUN: )
+// RUN: INPUT_DIR=%S/Inputs/checkdeps
+// RUN: DEPCHECK_INTERVAL=1
+// RUN: SLEEP_TIME=2
+
+// RUN: cp -R $INPUT_DIR/MyProject %t/
+// RUN: cp -R $INPUT_DIR/ClangFW.framework %t/Frameworks/
+// RUN: %empty-directory(%t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule)
+// RUN: %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src/Funcs.swift
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=global-config -completion-check-dependency-interval ${DEPCHECK_INTERVAL} == \
+
+// RUN:   -shell -- echo "### Initial" == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Modify framework (c)' == \
+// RUN:   -shell -- cp -R $INPUT_DIR/ClangFW.framework_mod/* %t/Frameworks/ClangFW.framework/ == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Fast completion' == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} \
+
+// RUN:   | %FileCheck %s
+
+
+// CHECK-LABEL: ### Initial
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Modify framework (c)
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc_mod()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Fast completion
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc_mod()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK: key.reusingastcontext: 1

test/SourceKit/CodeComplete/complete_checkdeps_otherfile.swift

@@ -0,0 +1,71 @@
+import ClangFW
+import SwiftFW
+
+func foo() {
+  /*HERE*/
+}
+
+// RUN: %empty-directory(%t/Frameworks)
+// RUN: %empty-directory(%t/MyProject)
+
+// RUN: COMPILER_ARGS=( \
+// RUN:   -target %target-triple \
+// RUN:   -module-name MyProject \
+// RUN:   -F %t/Frameworks \
+// RUN:   -I %t/MyProject \
+// RUN:   -import-objc-header %t/MyProject/Bridging.h \
+// RUN:   %t/MyProject/Library.swift \
+// RUN:   %s \
+// RUN: )
+// RUN: INPUT_DIR=%S/Inputs/checkdeps
+// RUN: DEPCHECK_INTERVAL=1
+// RUN: SLEEP_TIME=2
+
+// RUN: cp -R $INPUT_DIR/MyProject %t/
+// RUN: cp -R $INPUT_DIR/ClangFW.framework %t/Frameworks/
+// RUN: %empty-directory(%t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule)
+// RUN: %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src/Funcs.swift
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=global-config -completion-check-dependency-interval ${DEPCHECK_INTERVAL} == \
+
+// RUN:   -shell -- echo "### Initial" == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo "### Modify local library file" == \
+// RUN:   -shell -- cp -R $INPUT_DIR/MyProject_mod/Library.swift %t/MyProject/ == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Fast completion' == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} \
+
+// RUN:   | %FileCheck %s
+
+// CHECK-LABEL: ### Initial
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Modify local library file
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc_mod()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Fast completion
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc_mod()"
+// CHECK: ]
+// CHECK: key.reusingastcontext: 1

test/SourceKit/CodeComplete/complete_checkdeps_swiftmodule.swift

@@ -0,0 +1,71 @@
+import ClangFW
+import SwiftFW
+
+func foo() {
+  /*HERE*/
+}
+
+// RUN: %empty-directory(%t/Frameworks)
+// RUN: %empty-directory(%t/MyProject)
+
+// RUN: COMPILER_ARGS=( \
+// RUN:   -target %target-triple \
+// RUN:   -module-name MyProject \
+// RUN:   -F %t/Frameworks \
+// RUN:   -I %t/MyProject \
+// RUN:   -import-objc-header %t/MyProject/Bridging.h \
+// RUN:   %t/MyProject/Library.swift \
+// RUN:   %s \
+// RUN: )
+// RUN: INPUT_DIR=%S/Inputs/checkdeps
+// RUN: DEPCHECK_INTERVAL=1
+// RUN: SLEEP_TIME=2
+
+// RUN: cp -R $INPUT_DIR/MyProject %t/
+// RUN: cp -R $INPUT_DIR/ClangFW.framework %t/Frameworks/
+// RUN: %empty-directory(%t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule)
+// RUN: %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src/Funcs.swift
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=global-config -completion-check-dependency-interval ${DEPCHECK_INTERVAL} == \
+
+// RUN:   -shell -- echo "### Initial" == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Modify framework (s)' == \
+// RUN:   -shell --  %target-swift-frontend -emit-module -module-name SwiftFW -o %t/Frameworks/SwiftFW.framework/Modules/SwiftFW.swiftmodule/%target-swiftmodule-name $INPUT_DIR/SwiftFW_src_mod/Funcs.swift == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} == \
+
+// RUN:   -shell -- echo '### Fast completion' == \
+// RUN:   -shell -- sleep $SLEEP_TIME == \
+// RUN:   -req=complete -pos=5:3 %s -- ${COMPILER_ARGS[@]} \
+
+// RUN:   | %FileCheck %s
+
+// CHECK-LABEL: ### Initial
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Modify framework (s)
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc_mod()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK-NOT: key.reusingastcontext: 1
+
+// CHECK-LABEL: ### Fast completion
+// CHECK: key.results: [
+// CHECK-DAG: key.description: "clangFWFunc()"
+// CHECK-DAG: key.description: "swiftFWFunc_mod()"
+// CHECK-DAG: key.description: "localClangFunc()"
+// CHECK-DAG: key.description: "localSwiftFunc()"
+// CHECK: ]
+// CHECK: key.reusingastcontext: 1

tools/SourceKit/include/SourceKit/Core/Context.h

@@ -36,6 +36,9 @@ public:
     ///
     /// At the time of writing this just means ignoring .swiftsourceinfo files.
     bool OptimizeForIDE = false;
+
+    /// Interval second for checking dependencies in fast code completion.
+    unsigned CompletionCheckDependencyInterval = 5;
   };
 
 private:
@@ -43,8 +46,10 @@ private:
   mutable llvm::sys::Mutex Mtx;
 
 public:
-  Settings update(Optional<bool> OptimizeForIDE);
+  Settings update(Optional<bool> OptimizeForIDE,
+                  Optional<unsigned> CompletionCheckDependencyInterval);
   bool shouldOptimizeForIDE() const;
+  unsigned getCompletionCheckDependencyInterval() const;
 };
 
 class Context {

tools/SourceKit/include/SourceKit/Core/LangSupport.h

@@ -37,6 +37,7 @@ class SourceFileSyntax;
 } // namespace swift
 
 namespace SourceKit {
+class GlobalConfig;
 
 struct EntityInfo {
   UIdent Kind;
@@ -651,6 +652,8 @@ public:
 
   virtual ~LangSupport() { }
 
+  virtual void globalConfigurationUpdated(std::shared_ptr<GlobalConfig> Config) {};
+
   virtual void indexSource(StringRef Filename,
                            IndexingConsumer &Consumer,
                            ArrayRef<const char *> Args) = 0;

tools/SourceKit/lib/Core/Context.cpp

@@ -17,10 +17,13 @@
 using namespace SourceKit;
 
 GlobalConfig::Settings
-GlobalConfig::update(Optional<bool> OptimizeForIDE) {
+GlobalConfig::update(Optional<bool> OptimizeForIDE,
+                     Optional<unsigned> CompletionCheckDependencyInterval) {
   llvm::sys::ScopedLock L(Mtx);
   if (OptimizeForIDE.hasValue())
     State.OptimizeForIDE = *OptimizeForIDE;
+  if (CompletionCheckDependencyInterval.hasValue())
+    State.CompletionCheckDependencyInterval = *CompletionCheckDependencyInterval;
   return State;
 };
 
@@ -28,6 +31,10 @@ bool GlobalConfig::shouldOptimizeForIDE() const {
   llvm::sys::ScopedLock L(Mtx);
   return State.OptimizeForIDE;
 }
+unsigned GlobalConfig::getCompletionCheckDependencyInterval() const {
+  llvm::sys::ScopedLock L(Mtx);
+  return State.CompletionCheckDependencyInterval;
+}
 
 SourceKit::Context::Context(StringRef RuntimeLibPath,
     llvm::function_ref<std::unique_ptr<LangSupport>(Context &)>

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp

@@ -257,6 +257,13 @@ class InMemoryFileSystemProvider: public SourceKit::FileSystemProvider {
 };
 }
 
+static void
+configureCompletionInstance(std::shared_ptr<CompletionInstance> CompletionInst,
+                            std::shared_ptr<GlobalConfig> GlobalConfig) {
+  CompletionInst->setDependencyCheckIntervalSecond(
+      GlobalConfig->getCompletionCheckDependencyInterval());
+}
+
 SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
     : NotificationCtr(SKCtx.getNotificationCenter()),
       CCCache(new SwiftCompletionCache) {
@@ -270,7 +277,8 @@ SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
                                              SKCtx.getGlobalConfiguration(),
                                              Stats, RuntimeResourcePath);
 
-  CompletionInst = std::make_unique<CompletionInstance>();
+  CompletionInst = std::make_shared<CompletionInstance>();
+  configureCompletionInstance(CompletionInst, SKCtx.getGlobalConfiguration());
 
   // By default, just use the in-memory cache.
   CCCache->inMemory = std::make_unique<ide::CodeCompletionCache>();
@@ -282,6 +290,11 @@ SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
 SwiftLangSupport::~SwiftLangSupport() {
 }
 
+void SwiftLangSupport::globalConfigurationUpdated(
+    std::shared_ptr<GlobalConfig> Config) {
+  configureCompletionInstance(CompletionInst, Config);
+}
+
 UIdent SwiftLangSupport::getUIDForDecl(const Decl *D, bool IsRef) {
   return UIdentVisitor(IsRef).visit(const_cast<Decl*>(D));
 }

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h

@@ -450,6 +450,8 @@ public:
   // LangSupport Interface
   //==========================================================================//
 
+  void globalConfigurationUpdated(std::shared_ptr<GlobalConfig> Config) override;
+
   void indexSource(StringRef Filename, IndexingConsumer &Consumer,
                    ArrayRef<const char *> Args) override;
 

tools/SourceKit/tools/sourcekitd-test/Options.td

@@ -143,6 +143,11 @@ def vfs_name : Separate<["-"], "vfs-name">,
 def optimize_for_ide : Joined<["-"], "for-ide=">,
   HelpText<"Value for the OptimizeForIde global configuration setting">;
 
+def completion_check_dependency_interval : Separate<["-"], "completion-check-dependency-interval">,
+  HelpText<"Inteval seconds for checking dependencies in fast completion">;
+def completion_check_dependency_interval_EQ : Joined<["-"], "completion-check-dependency-interval=">,
+  Alias<completion_check_dependency_interval>;
+
 def suppress_config_request : Flag<["-"], "suppress-config-request">,
   HelpText<"Suppress the default global configuration request, that is otherwise sent before any other request (except for the global-config request itself)">;
 

tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp

@@ -381,6 +381,19 @@ bool TestOptions::parseArgs(llvm::ArrayRef<const char *> Args) {
       break;
     }
 
+    case OPT_completion_check_dependency_interval: {
+      int64_t Value;
+      if (StringRef(InputArg->getValue()).getAsInteger(10, Value)) {
+        llvm::errs() << "error: expected number for inteval\n";
+        return true;
+      } else if (Value < 0) {
+        llvm::errs() << "error: completion-check-dependency-interval must be > 0\n";
+        return true;
+      }
+      CompletionCheckDependencyInterval = Value;
+      break;
+    }
+
     case OPT_suppress_config_request:
       SuppressDefaultConfigRequest = true;
       break;

tools/SourceKit/tools/sourcekitd-test/TestOptions.h

@@ -114,6 +114,7 @@ struct TestOptions {
   bool timeRequest = false;
   llvm::Optional<bool> OptimizeForIde;
   bool SuppressDefaultConfigRequest = false;
+  llvm::Optional<unsigned> CompletionCheckDependencyInterval;
   unsigned repeatRequest = 1;
   struct VFSFile {
     std::string path;

tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp

@@ -548,7 +548,14 @@ static int handleTestInvocation(TestOptions Opts, TestOptions &InitOpts) {
   case SourceKitRequest::GlobalConfiguration:
     sourcekitd_request_dictionary_set_uid(Req, KeyRequest, RequestGlobalConfiguration);
     if (Opts.OptimizeForIde.hasValue())
-      sourcekitd_request_dictionary_set_int64(Req, KeyOptimizeForIDE, static_cast<int64_t>(Opts.OptimizeForIde.getValue()));
+      sourcekitd_request_dictionary_set_int64(
+          Req, KeyOptimizeForIDE,
+          static_cast<int64_t>(Opts.OptimizeForIde.getValue()));
+    if (Opts.CompletionCheckDependencyInterval.hasValue())
+      sourcekitd_request_dictionary_set_int64(
+          Req, KeyCompletionCheckDependencyInterval,
+          static_cast<int64_t>(
+              Opts.CompletionCheckDependencyInterval.getValue()));
     break;
 
   case SourceKitRequest::ProtocolVersion:

tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp

@@ -438,9 +438,21 @@ void handleRequestImpl(sourcekitd_object_t ReqObj, ResponseReceiver Rec) {
     if (!Req.getInt64(KeyOptimizeForIDE, EditorMode, true)) {
       OptimizeForIDE = EditorMode;
     }
+    Optional<unsigned> CompletionCheckDependencyInterval;
+    int64_t IntervalValue = 0;
+    if (!Req.getInt64(KeyCompletionCheckDependencyInterval,
+                      IntervalValue, /*isOptional=*/true))
+      CompletionCheckDependencyInterval = IntervalValue;
+
+    GlobalConfig::Settings UpdatedConfig = Config->update(
+        OptimizeForIDE, CompletionCheckDependencyInterval);
+
+    getGlobalContext().getSwiftLangSupport().globalConfigurationUpdated(Config);
 
-    GlobalConfig::Settings UpdatedConfig = Config->update(OptimizeForIDE);
     dict.set(KeyOptimizeForIDE, UpdatedConfig.OptimizeForIDE);
+    dict.set(KeyCompletionCheckDependencyInterval,
+             UpdatedConfig.CompletionCheckDependencyInterval);
+
     return Rec(RB.createResponse());
   }
   if (ReqUID == RequestProtocolVersion) {

utils/gyb_sourcekit_support/UIDs.py

@@ -179,6 +179,8 @@ UID_KEYS = [
     KEY('OptimizeForIDE', 'key.optimize_for_ide'),
     KEY('RequiredBystanders', 'key.required_bystanders'),
     KEY('ReusingASTContext', 'key.reusingastcontext'),
+    KEY('CompletionCheckDependencyInterval',
+        'key.completion_check_dependency_interval'),
 ]