[cling] Use clang-repl-style code completion

interpreter/cling/include/cling/Interpreter/CIFactory.h

@@ -38,7 +38,8 @@ namespace cling {
     clang::CompilerInstance*
     createCI(llvm::StringRef Code, const InvocationOptions& Opts,
              const char* LLVMDir, std::unique_ptr<clang::ASTConsumer> consumer,
-             const ModuleFileExtensions& moduleExtensions);
+             const ModuleFileExtensions& moduleExtensions,
+             bool AutoComplete = false);
 
     clang::CompilerInstance*
     createCI(MemBufPtr_t Buffer, int Argc, const char* const* Argv,

interpreter/cling/include/cling/Interpreter/ClingCodeCompleteConsumer.h

@@ -14,6 +14,10 @@
 
 using namespace clang;
 
+namespace clang {
+  class CompilerInstance;
+}
+
 namespace cling {
   /// \brief Create a new printing code-completion consumer that prints its
   /// results to the given raw output stream.
@@ -50,6 +54,28 @@ namespace cling {
       completions = m_Completions;
     }
   };
+
+  struct ClingCodeCompleter {
+    ClingCodeCompleter() = default;
+    std::string Prefix;
+
+    /// \param InterpCI [in] The compiler instance that is used to trigger code
+    /// completion
+
+    /// \param Content [in] The string where code completion is triggered.
+
+    /// \param Line [in] The line number of the code completion point.
+
+    /// \param Col [in] The column number of the code completion point.
+
+    /// \param ParentCI [in] The running interpreter compiler instance that
+    /// provides ASTContexts.
+
+    /// \param CCResults [out] The completion results.
+    void codeComplete(CompilerInstance* InterpCI, llvm::StringRef Content,
+                      unsigned Line, unsigned Col, CompilerInstance* ParentCI,
+                      std::vector<std::string>& CCResults);
+  };
 }
 
 #endif

interpreter/cling/lib/Interpreter/CIFactory.cpp

@@ -42,6 +42,7 @@
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -1252,13 +1253,61 @@ namespace {
     }
   }
 
+  // Goal is to make this as close to the function in
+  // clang/lib/Interpreter/Interpreter.cpp taking only clang arguments
+  static llvm::Expected<std::unique_ptr<CompilerInstance>>
+  CreateCI(const std::vector<const char*>& ClangArgv, std::string ExeName,
+           std::unique_ptr<clang::driver::Compilation>& Compilation) {
+    auto InvocationPtr = std::make_shared<clang::CompilerInvocation>();
+
+    // The compiler invocation is the owner of the diagnostic options.
+    // Everything else points to them.
+    DiagnosticOptions& DiagOpts = InvocationPtr->getDiagnosticOpts();
+    llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
+        SetupDiagnostics(DiagOpts, ExeName);
+    if (!Diags) {
+      cling::errs() << "Could not setup diagnostic engine.\n";
+      return nullptr;
+    }
+
+    llvm::Triple TheTriple(llvm::sys::getProcessTriple());
+    clang::driver::Driver Drvr(ClangArgv[0], TheTriple.getTriple(), *Diags);
+    // Drvr.setWarnMissingInput(false);
+    Drvr.setCheckInputsExist(false); // think foo.C(12)
+    llvm::ArrayRef<const char*> RF(&(ClangArgv[0]), ClangArgv.size());
+    Compilation.reset(Drvr.BuildCompilation(RF));
+    if (!Compilation) {
+      cling::errs() << "Couldn't create clang::driver::Compilation.\n";
+      return nullptr;
+    }
+
+    const llvm::opt::ArgStringList* CC1Args =
+        GetCC1Arguments(Compilation.get());
+    if (!CC1Args) {
+      cling::errs() << "Could not get cc1 arguments.\n";
+      return nullptr;
+    }
+
+    clang::CompilerInvocation::CreateFromArgs(*InvocationPtr, *CC1Args, *Diags);
+    // We appreciate the error message about an unknown flag (or do we? if not
+    // we should switch to a different DiagEngine for parsing the flags).
+    // But in general we'll happily go on.
+    Diags->Reset();
+
+    // Create and setup a compiler instance.
+    std::unique_ptr<CompilerInstance> CI(new CompilerInstance());
+    CI->setInvocation(InvocationPtr);
+    CI->setDiagnostics(Diags.get()); // Diags is ref-counted
+
+    return CI;
+  }
+
   static CompilerInstance*
   createCIImpl(std::unique_ptr<llvm::MemoryBuffer> Buffer,
-               const CompilerOptions& COpts,
-               const char* LLVMDir,
+               const CompilerOptions& COpts, const char* LLVMDir,
                std::unique_ptr<clang::ASTConsumer> customConsumer,
                const CIFactory::ModuleFileExtensions& moduleExtensions,
-               bool OnlyLex, bool HasInput = false) {
+               bool OnlyLex, bool HasInput = false, bool AutoComplete = false) {
     // Follow clang -v convention of printing version on first line
     if (COpts.Verbose)
       cling::log() << "cling version " << ClingStringify(CLING_VERSION) << '\n';
@@ -1405,58 +1454,37 @@ namespace {
   #endif
     }
 #endif
-
-    if (!COpts.HasOutput || !HasInput) {
+    if ((!COpts.HasOutput || !HasInput) && !AutoComplete) {
       argvCompile.push_back("-");
     }
 
-    auto InvocationPtr = std::make_shared<clang::CompilerInvocation>();
+    if (AutoComplete) {
+      // Put a dummy C++ file on to ensure there's at least one compile job for
+      // the driver to construct.
+      argvCompile.push_back("<<< cling interactive line includer >>>");
+    }
 
-    // The compiler invocation is the owner of the diagnostic options.
-    // Everything else points to them.
-    DiagnosticOptions& DiagOpts = InvocationPtr->getDiagnosticOpts();
     // add prefix to diagnostic messages if second compiler instance is existing
     // e.g. in CUDA mode
     std::string ExeName = "";
     if (COpts.CUDAHost)
       ExeName = "cling";
     if (COpts.CUDADevice)
       ExeName = "cling-ptx";
-    llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
-        SetupDiagnostics(DiagOpts, ExeName);
-    if (!Diags) {
-      cling::errs() << "Could not setup diagnostic engine.\n";
-      return nullptr;
-    }
 
-    llvm::Triple TheTriple(llvm::sys::getProcessTriple());
-    clang::driver::Driver Drvr(argv[0], TheTriple.getTriple(), *Diags);
-    //Drvr.setWarnMissingInput(false);
-    Drvr.setCheckInputsExist(false); // think foo.C(12)
-    llvm::ArrayRef<const char*>RF(&(argvCompile[0]), argvCompile.size());
-    std::unique_ptr<clang::driver::Compilation>
-      Compilation(Drvr.BuildCompilation(RF));
-    if (!Compilation) {
-      cling::errs() << "Couldn't create clang::driver::Compilation.\n";
-      return nullptr;
-    }
+    std::unique_ptr<clang::driver::Compilation> Compilation;
 
-    const llvm::opt::ArgStringList* CC1Args = GetCC1Arguments(Compilation.get());
-    if (!CC1Args) {
-      cling::errs() << "Could not get cc1 arguments.\n";
+    auto CIOrErr = CreateCI(argvCompile, ExeName, Compilation);
+    if (!CIOrErr) {
+      cling::errs() << "Could not create CI: " << CIOrErr.takeError() << "\n";
       return nullptr;
     }
+    std::unique_ptr<clang::CompilerInstance> CI = std::move(*CIOrErr);
 
-    clang::CompilerInvocation::CreateFromArgs(*InvocationPtr, *CC1Args, *Diags);
-    // We appreciate the error message about an unknown flag (or do we? if not
-    // we should switch to a different DiagEngine for parsing the flags).
-    // But in general we'll happily go on.
-    Diags->Reset();
+    DiagnosticsEngine& Diags = CI->getDiagnostics();
+    CompilerInvocation& Invocation = CI->getInvocation();
+    DiagnosticOptions& DiagOpts = Invocation.getDiagnosticOpts();
 
-    // Create and setup a compiler instance.
-    std::unique_ptr<CompilerInstance> CI(new CompilerInstance());
-    CI->setInvocation(InvocationPtr);
-    CI->setDiagnostics(Diags.get()); // Diags is ref-counted
     if (!OnlyLex)
       CI->getDiagnosticOpts().ShowColors =
         llvm::sys::Process::StandardOutIsDisplayed() ||
@@ -1469,9 +1497,9 @@ namespace {
     // Copied from CompilerInstance::createDiagnostics:
     // Chain in -verify checker, if requested.
     if (DiagOpts.VerifyDiagnostics)
-      Diags->setClient(new clang::VerifyDiagnosticConsumer(*Diags));
+      Diags.setClient(new clang::VerifyDiagnosticConsumer(Diags));
     // Configure our handling of diagnostics.
-    ProcessWarningOptions(*Diags, DiagOpts);
+    ProcessWarningOptions(Diags, DiagOpts);
 
     if (COpts.HasOutput && !OnlyLex) {
       ActionScan scan(clang::driver::Action::PrecompileJobClass,
@@ -1484,14 +1512,13 @@ namespace {
       if (!SetupCompiler(CI.get(), COpts))
         return nullptr;
 
-      ProcessWarningOptions(*Diags, DiagOpts);
+      ProcessWarningOptions(Diags, DiagOpts);
       return CI.release();
     }
 
     IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> Overlay =
         new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem());
     CI->createFileManager(Overlay);
-    clang::CompilerInvocation& Invocation = CI->getInvocation();
     std::string& PCHFile = Invocation.getPreprocessorOpts().ImplicitPCHInclude;
     bool InitLang = true, InitTarget = true;
     if (!PCHFile.empty()) {
@@ -1543,14 +1570,14 @@ namespace {
           // When running interactively pass on the info that the PCH
           // has failed so that IncrmentalParser::Initialize won't try again.
           if (!HasInput && llvm::sys::Process::StandardInIsUserInput()) {
-            const unsigned ID = Diags->getCustomDiagID(
-                                       clang::DiagnosticsEngine::Level::Error,
-                                       "Problems loading PCH: '%0'.");
-            
-            Diags->Report(ID) << PCHFile;
+            const unsigned ID =
+                Diags.getCustomDiagID(clang::DiagnosticsEngine::Level::Error,
+                                      "Problems loading PCH: '%0'.");
+
+            Diags.Report(ID) << PCHFile;
             // If this was the only error, then don't let it stop anything
-            if (Diags->getClient()->getNumErrors() == 1)
-              Diags->Reset(true);
+            if (Diags.getClient()->getNumErrors() == 1)
+              Diags.Reset(true);
             // Clear the include so no one else uses it.
             std::string().swap(PCHFile);
           }
@@ -1612,7 +1639,14 @@ namespace {
       = const_cast<SrcMgr::ContentCache&>(MainFileFI.getContentCache());
     if (!Buffer)
       Buffer = llvm::MemoryBuffer::getMemBuffer("/*CLING DEFAULT MEMBUF*/;\n");
-    MainFileCC.setBuffer(std::move(Buffer));
+    if (AutoComplete) {
+      // Adapted from upstream clang/lib/Interpreter/Interpreter.cpp
+      // FIXME: Merge with CompilerInstance::ExecuteAction.
+      llvm::MemoryBuffer* MB = Buffer.release();
+      CI->getPreprocessorOpts().addRemappedFile(Filename, MB);
+    } else {
+      MainFileCC.setBuffer(std::move(Buffer));
+    }
 
     // Create TargetInfo for the other side of CUDA and OpenMP compilation.
     if ((CI->getLangOpts().CUDA || CI->getLangOpts().OpenMPIsTargetDevice) &&
@@ -1780,16 +1814,17 @@ namespace {
 
 namespace cling {
 
-CompilerInstance*
-CIFactory::createCI(llvm::StringRef Code, const InvocationOptions& Opts,
-                    const char* LLVMDir,
-                    std::unique_ptr<clang::ASTConsumer> consumer,
-                    const ModuleFileExtensions& moduleExtensions) {
-  return createCIImpl(llvm::MemoryBuffer::getMemBuffer(Code), Opts.CompilerOpts,
-                      LLVMDir, std::move(consumer), moduleExtensions,
-                      false /*OnlyLex*/,
-                      !Opts.IsInteractive());
-}
+  CompilerInstance*
+  CIFactory::createCI(llvm::StringRef Code, const InvocationOptions& Opts,
+                      const char* LLVMDir,
+                      std::unique_ptr<clang::ASTConsumer> consumer,
+                      const ModuleFileExtensions& moduleExtensions,
+                      bool AutoComplete /*false*/) {
+    return createCIImpl(llvm::MemoryBuffer::getMemBuffer(Code),
+                        Opts.CompilerOpts, LLVMDir, std::move(consumer),
+                        moduleExtensions, false /*OnlyLex*/,
+                        !Opts.IsInteractive(), AutoComplete);
+  }
 
 CompilerInstance* CIFactory::createCI(
     MemBufPtr_t Buffer, int argc, const char* const* argv, const char* LLVMDir,