[CTU] Add statistics

[a_sidorin]

Hi Gabor,
Sorry, but I don't understand the meaning of some options. Could you please explain what are NumNoUnit and NumNotInOtherTU and what is the difference between them?

[xazax.hun]

The code LGTM! I am not good at wordsmithing, but if the descriptions of the statistics are not clear enough, I agree that they should be rephrased.

[martong]

• Remove NumNoUnit

[martong]

Sorry, but I don't understand the meaning of some options. Could you please explain what are NumNoUnit and NumNotInOtherTU and what is the difference between them?

Your point is absolutely true. They are the same, I think at some point some time ago they were different (in our fork), now it is just redundancy. So I removed NumNoUnit.

[martong]

• Remove braces

[martong]

Sorry, but I don't understand the meaning of some options. Could you please explain what are NumNoUnit and NumNotInOtherTU and what is the difference between them?

Your point is absolutely true. They are the same, I think at some point some time ago they were different (in our fork), now it is just redundancy. So I removed NumNoUnit.

They are the same because in loadExternalAST we must return witn a non nullptr value, so it seems like the second check is redundant here:

if (!ASTUnitOrError) {
  return ASTUnitOrError.takeError();
}
ASTUnit *Unit = *ASTUnitOrError;
if (!Unit)
  return llvm::make_error<IndexError>(
      index_error_code::failed_to_get_external_ast);

I am going to open another patch to fix this.

[a_sidorin]

LGTM with a nit.

lib/CrossTU/CrossTranslationUnit.cpp

171

We can omit braces here.

[martong]

lib/CrossTU/CrossTranslationUnit.cpp

171

Ok, thanks, I changed that.

lib/CrossTU/CrossTranslationUnit.cpp

 #include "clang/Basic/TargetInfo.h"
 #include "clang/CrossTU/CrossTUDiagnostic.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Index/USRGeneration.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include <fstream>
 #include <sstream>
 
 namespace clang {
 namespace cross_tu {
 
 namespace {
+#define DEBUG_TYPE "CrossTranslationUnit"
+STATISTIC(NumGetCTUCalled, "The # of getCTUDefinition function called");
+STATISTIC(
+    NumNotInOtherTU,
+    "The # of getCTUDefinition called but the function is not in any other TU");
+STATISTIC(NumGetCTUSuccess,
+          "The # of getCTUDefinition successfully returned the "
+          "requested function's body");
+
 // FIXME: This class is will be removed after the transition to llvm::Error.
 class IndexErrorCategory : public std::error_category {
 public:
   const char *name() const noexcept override { return "clang.index"; }
 
   std::string message(int Condition) const override {
     switch (static_cast<index_error_code>(Condition)) {
     case index_error_code::unspecified:
CrossTranslationUnitContext::findFunctionInDeclContext(const DeclContext *DC,
   return nullptr;
 }
 
 llvm::Expected<const FunctionDecl *>
 CrossTranslationUnitContext::getCrossTUDefinition(const FunctionDecl *FD,
                                                   StringRef CrossTUDir,
                                                   StringRef IndexName) {
   assert(!FD->hasBody() && "FD has a definition in current translation unit!");
+  ++NumGetCTUCalled;
   const std::string LookupFnName = getLookupName(FD);
   if (LookupFnName.empty())
     return llvm::make_error<IndexError>(
         index_error_code::failed_to_generate_usr);
   llvm::Expected<ASTUnit *> ASTUnitOrError =
       loadExternalAST(LookupFnName, CrossTUDir, IndexName);
-  if (!ASTUnitOrError)
+  if (!ASTUnitOrError) {
     return ASTUnitOrError.takeError();
+  }
   ASTUnit *Unit = *ASTUnitOrError;
   if (!Unit)
     return llvm::make_error<IndexError>(
         index_error_code::failed_to_get_external_ast);
   assert(&Unit->getFileManager() ==
          &Unit->getASTContext().getSourceManager().getFileManager());
 
   TranslationUnitDecl *TU = Unit->getASTContext().getTranslationUnitDecl();
if (FunctionFileMap.empty()) {
           parseCrossTUIndex(IndexFile, CrossTUDir);
       if (IndexOrErr)
         FunctionFileMap = *IndexOrErr;
       else
         return IndexOrErr.takeError();
     }
 
     auto It = FunctionFileMap.find(LookupName);
-    if (It == FunctionFileMap.end())
+    if (It == FunctionFileMap.end()) {
+      ++NumNotInOtherTU;
       return llvm::make_error<IndexError>(index_error_code::missing_definition);
+    }
     StringRef ASTFileName = It->second;
     auto ASTCacheEntry = FileASTUnitMap.find(ASTFileName);
     if (ASTCacheEntry == FileASTUnitMap.end()) {
       IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
       TextDiagnosticPrinter *DiagClient =
           new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
       IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
       IntrusiveRefCntPtr<DiagnosticsEngine> Diags(

 
 llvm::Expected<const FunctionDecl *>
 CrossTranslationUnitContext::importDefinition(const FunctionDecl *FD) {
   ASTImporter &Importer = getOrCreateASTImporter(FD->getASTContext());
   auto *ToDecl =
       cast<FunctionDecl>(Importer.Import(const_cast<FunctionDecl *>(FD)));
   assert(ToDecl->hasBody());
   assert(FD->hasBody() && "Functions already imported should have body.");
+  ++NumGetCTUSuccess;
   return ToDecl;
 }
 
 ASTImporter &
 CrossTranslationUnitContext::getOrCreateASTImporter(ASTContext &From) {
   auto I = ASTUnitImporterMap.find(From.getTranslationUnitDecl());
   if (I != ASTUnitImporterMap.end())
     return *I->second;