[SourceKit] Allow executing a completion-like operation without inserting a code completion token into the buffer

We will use this for solver-based cursor info, which doesn’t use code completion tokens.

Author: ahoppen

tools/SourceKit/lib/SwiftLang/SwiftCompletion.cpp

@@ -105,7 +105,8 @@ static void swiftCodeCompleteImpl(
   CompletionContext.setAddCallWithNoDefaultArgs(opts.addCallWithNoDefaultArgs);
 
   Lang.performWithParamsToCompletionLikeOperation(
-      UnresolvedInputFile, Offset, Args, FileSystem, CancellationToken,
+      UnresolvedInputFile, Offset, /*InsertCodeCompletionToken=*/true, Args,
+      FileSystem, CancellationToken,
       [&](CancellableResult<SwiftLangSupport::CompletionLikeOperationParams>
               ParamsResult) {
         ParamsResult.mapAsync<CodeCompleteResult>(

tools/SourceKit/lib/SwiftLang/SwiftConformingMethodList.cpp

@@ -176,7 +176,8 @@ void SwiftLangSupport::getConformingMethodList(
   }
 
   performWithParamsToCompletionLikeOperation(
-      UnresolvedInputFile, Offset, Args, fileSystem, CancellationToken,
+      UnresolvedInputFile, Offset, /*InsertCodeCompletionToken=*/true, Args,
+      fileSystem, CancellationToken,
       [&](CancellableResult<CompletionLikeOperationParams> ParmsResult) {
         ParmsResult.mapAsync<ConformingMethodListResults>(
             [&](auto &Params, auto DeliverTransformed) {

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp

@@ -1008,7 +1008,7 @@ SwiftLangSupport::getFileSystem(const Optional<VFSOptions> &vfsOptions,
 
 void SwiftLangSupport::performWithParamsToCompletionLikeOperation(
     llvm::MemoryBuffer *UnresolvedInputFile, unsigned Offset,
-    ArrayRef<const char *> Args,
+    bool InsertCodeCompletionToken, ArrayRef<const char *> Args,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
     SourceKitCancellationToken CancellationToken,
     llvm::function_ref<void(CancellableResult<CompletionLikeOperationParams>)>
@@ -1026,8 +1026,18 @@ void SwiftLangSupport::performWithParamsToCompletionLikeOperation(
   // Create a buffer for code completion. This contains '\0' at 'Offset'
   // position of 'UnresolvedInputFile' buffer.
   auto origOffset = Offset;
-  auto newBuffer = ide::makeCodeCompletionMemoryBuffer(
-      UnresolvedInputFile, Offset, bufferIdentifier);
+
+  // If we inserted a code completion token into the buffer, this keeps the
+  // buffer alive. Should never be accessed, `buffer` should be used instead.
+  std::unique_ptr<llvm::MemoryBuffer> codeCompletionBuffer;
+  llvm::MemoryBuffer *buffer;
+  if (InsertCodeCompletionToken) {
+    codeCompletionBuffer = ide::makeCodeCompletionMemoryBuffer(
+        UnresolvedInputFile, Offset, bufferIdentifier);
+    buffer = codeCompletionBuffer.get();
+  } else {
+    buffer = UnresolvedInputFile;
+  }
 
   SourceManager SM;
   DiagnosticEngine Diags(SM);
@@ -1055,7 +1065,7 @@ void SwiftLangSupport::performWithParamsToCompletionLikeOperation(
   std::string CompilerInvocationError;
   bool CreatingInvocationFailed = getASTManager()->initCompilerInvocation(
       Invocation, Args, FrontendOptions::ActionType::Typecheck, Diags,
-      newBuffer->getBufferIdentifier(), FileSystem, CompilerInvocationError);
+      buffer->getBufferIdentifier(), FileSystem, CompilerInvocationError);
   if (CreatingInvocationFailed) {
     PerformOperation(CancellableResult<CompletionLikeOperationParams>::failure(
         CompilerInvocationError));
@@ -1075,7 +1085,7 @@ void SwiftLangSupport::performWithParamsToCompletionLikeOperation(
     CancellationFlag->store(true, std::memory_order_relaxed);
   });
 
-  CompletionLikeOperationParams Params = {Invocation, newBuffer.get(), &CIDiags,
+  CompletionLikeOperationParams Params = {Invocation, buffer, &CIDiags,
                                           CancellationFlag};
   PerformOperation(
       CancellableResult<CompletionLikeOperationParams>::success(Params));

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h

@@ -516,9 +516,12 @@ class SwiftLangSupport : public LangSupport {
 
   /// Execute \p PerformOperation synchronously with the parameters necessary to
   /// invoke a completion-like operation on \c CompletionInstance.
+  /// If \p InsertCodeCompletionToken is \c true, a code completion token will
+  /// be inserted into the source buffer, if \p InsertCodeCompletionToken is \c
+  /// false, the buffer is left as-is.
   void performWithParamsToCompletionLikeOperation(
       llvm::MemoryBuffer *UnresolvedInputFile, unsigned Offset,
-      ArrayRef<const char *> Args,
+      bool InsertCodeCompletionToken, ArrayRef<const char *> Args,
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem,
       SourceKitCancellationToken CancellationToken,
       llvm::function_ref<

tools/SourceKit/lib/SwiftLang/SwiftTypeContextInfo.cpp

@@ -146,7 +146,8 @@ void SwiftLangSupport::getExpressionContextInfo(
   }
 
   performWithParamsToCompletionLikeOperation(
-      UnresolvedInputFile, Offset, Args, fileSystem, CancellationToken,
+      UnresolvedInputFile, Offset, /*InsertCodeCompletionToken=*/true, Args,
+      fileSystem, CancellationToken,
       [&](CancellableResult<CompletionLikeOperationParams> ParamsResult) {
         ParamsResult.mapAsync<TypeContextInfoResult>(
             [&](auto &CIParams, auto DeliverTransformed) {