[libclang] Introduce options to control the priority for the threads

that libclang creates.

-Introduce CXGlobalOptFlags enum for the new options that can be
 set on the CXIndex object.

-CXGlobalOpt_ThreadBackgroundPriorityForIndexing affects:
  clang_indexSourceFile
  clang_indexTranslationUnit
  clang_parseTranslationUnit
  clang_saveTranslationUnit

-CXGlobalOpt_ThreadBackgroundPriorityForEditing affects:
  clang_reparseTranslationUnit
  clang_codeCompleteAt
  clang_annotateTokens

rdar://9075282

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153562 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 76 insertions, 6 deletions

diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index b3a29ef105..3882d7bc95 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -52,10 +52,11 @@ using namespace clang::cxcursor;
 using namespace clang::cxstring;
 using namespace clang::cxtu;
 
-CXTranslationUnit cxtu::MakeCXTranslationUnit(ASTUnit *TU) {
+CXTranslationUnit cxtu::MakeCXTranslationUnit(CIndexer *CIdx, ASTUnit *TU) {
   if (!TU)
     return 0;
   CXTranslationUnit D = new CXTranslationUnitImpl();
+  D->CIdx = CIdx;
   D->TUData = TU;
   D->StringPool = createCXStringPool();
   D->Diagnostics = 0;
@@ -2411,6 +2412,14 @@ CXIndex clang_createIndex(int excludeDeclarationsFromPCH,
     CIdxr->setOnlyLocalDecls();
   if (displayDiagnostics)
     CIdxr->setDisplayDiagnostics();
+
+  if (getenv("LIBCLANG_BGPRIO_INDEX"))
+    CIdxr->setCXGlobalOptFlags(CIdxr->getCXGlobalOptFlags() |
+                               CXGlobalOpt_ThreadBackgroundPriorityForIndexing);
+  if (getenv("LIBCLANG_BGPRIO_EDIT"))
+    CIdxr->setCXGlobalOptFlags(CIdxr->getCXGlobalOptFlags() |
+                               CXGlobalOpt_ThreadBackgroundPriorityForEditing);
+
   return CIdxr;
 }
 
@@ -2419,6 +2428,17 @@ void clang_disposeIndex(CXIndex CIdx) {
     delete static_cast<CIndexer *>(CIdx);
 }
 
+void clang_CXIndex_setGlobalOptions(CXIndex CIdx, unsigned options) {
+  if (CIdx)
+    static_cast<CIndexer *>(CIdx)->setCXGlobalOptFlags(options);
+}
+
+unsigned clang_CXIndex_getGlobalOptions(CXIndex CIdx) {
+  if (CIdx)
+    return static_cast<CIndexer *>(CIdx)->getCXGlobalOptFlags();
+  return 0;
+}
+
 void clang_toggleCrashRecovery(unsigned isEnabled) {
   if (isEnabled)
     llvm::CrashRecoveryContext::Enable();
@@ -2441,7 +2461,7 @@ CXTranslationUnit clang_createTranslationUnit(CXIndex CIdx,
                                   0, 0,
                                   /*CaptureDiagnostics=*/true,
                                   /*AllowPCHWithCompilerErrors=*/true);
-  return MakeCXTranslationUnit(TU);
+  return MakeCXTranslationUnit(CXXIdx, TU);
 }
 
 unsigned clang_defaultEditingTranslationUnitOptions() {
@@ -2490,6 +2510,9 @@ static void clang_parseTranslationUnit_Impl(void *UserData) {
 
   CIndexer *CXXIdx = static_cast<CIndexer *>(CIdx);
 
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
+    setBackGroundPriority();
+
   bool PrecompilePreamble = options & CXTranslationUnit_PrecompiledPreamble;
   // FIXME: Add a flag for modules.
   TranslationUnitKind TUKind
@@ -2601,7 +2624,7 @@ static void clang_parseTranslationUnit_Impl(void *UserData) {
     }
   }
 
-  PTUI->result = MakeCXTranslationUnit(Unit.take());
+  PTUI->result = MakeCXTranslationUnit(CXXIdx, Unit.take());
 }
 CXTranslationUnit clang_parseTranslationUnit(CXIndex CIdx,
                                              const char *source_filename,
@@ -2663,6 +2686,10 @@ static void clang_saveTranslationUnit_Impl(void *UserData) {
   SaveTranslationUnitInfo *STUI =
     static_cast<SaveTranslationUnitInfo*>(UserData);
 
+  CIndexer *CXXIdx = (CIndexer*)STUI->TU->CIdx;
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
+    setBackGroundPriority();
+
   STUI->result = static_cast<ASTUnit *>(STUI->TU->TUData)->Save(STUI->FileName);
 }
 
@@ -2750,6 +2777,10 @@ static void clang_reparseTranslationUnit_Impl(void *UserData) {
   if (!TU)
     return;
 
+  CIndexer *CXXIdx = (CIndexer*)TU->CIdx;
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForEditing))
+    setBackGroundPriority();
+
   ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   ASTUnit::ConcurrencyCheck Check(*CXXUnit);
   
@@ -5133,6 +5164,10 @@ static void clang_annotateTokensImpl(void *UserData) {
   const unsigned NumTokens = ((clang_annotateTokens_Data*)UserData)->NumTokens;
   CXCursor *Cursors = ((clang_annotateTokens_Data*)UserData)->Cursors;
 
+  CIndexer *CXXIdx = (CIndexer*)TU->CIdx;
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForEditing))
+    setBackGroundPriority();
+
   // Determine the region of interest, which contains all of the tokens.
   SourceRange RegionOfInterest;
   RegionOfInterest.setBegin(
@@ -5704,6 +5739,13 @@ void SetSafetyThreadStackSize(unsigned Value) {
   SafetyStackThreadSize = Value;
 }
 
+void clang::setBackGroundPriority() {
+  // FIXME: Move to llvm/Support and make it cross-platform.
+#ifdef __APPLE__
+  setpriority(PRIO_DARWIN_THREAD, 0, PRIO_DARWIN_BG);
+#endif
+}
+
 }
 
 extern "C" {
diff --git a/tools/libclang/CIndexCodeCompletion.cpp b/tools/libclang/CIndexCodeCompletion.cpp
index 1b4a7e4800..c5bc8c8dd4 100644
--- a/tools/libclang/CIndexCodeCompletion.cpp
+++ b/tools/libclang/CIndexCodeCompletion.cpp
@@ -666,6 +666,10 @@ void clang_codeCompleteAt_Impl(void *UserData) {
   if (!AST)
     return;
 
+  CIndexer *CXXIdx = (CIndexer*)TU->CIdx;
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForEditing))
+    setBackGroundPriority();
+
   ASTUnit::ConcurrencyCheck Check(*AST);
 
   // Perform the remapping of source files.
diff --git a/tools/libclang/CIndexer.h b/tools/libclang/CIndexer.h
index de7cc88a2c..f8cb8dc1fe 100644
--- a/tools/libclang/CIndexer.h
+++ b/tools/libclang/CIndexer.h
@@ -29,12 +29,14 @@ namespace clang {
 class CIndexer {
   bool OnlyLocalDecls;
   bool DisplayDiagnostics;
+  unsigned Options; // CXGlobalOptFlags.
 
   llvm::sys::Path ResourcesPath;
   std::string WorkingDir;
 
 public:
- CIndexer() : OnlyLocalDecls(false), DisplayDiagnostics(false) { }
+ CIndexer() : OnlyLocalDecls(false), DisplayDiagnostics(false),
+              Options(CXGlobalOpt_None) { }
   
   /// \brief Whether we only want to see "local" declarations (that did not
   /// come from a previous precompiled header). If false, we want to see all
@@ -47,6 +49,13 @@ public:
     DisplayDiagnostics = Display;
   }
 
+  unsigned getCXGlobalOptFlags() const { return Options; }
+  void setCXGlobalOptFlags(unsigned options) { Options = options; }
+
+  bool isOptEnabled(CXGlobalOptFlags opt) const {
+    return Options & ~unsigned(opt);
+  }
+
   /// \brief Get the path of the clang resource files.
   std::string getClangResourcesPath();
 
@@ -79,6 +88,10 @@ public:
   bool RunSafely(llvm::CrashRecoveryContext &CRC,
                  void (*Fn)(void*), void *UserData, unsigned Size = 0);
 
+  /// \brief Set the thread priority to background.
+  /// FIXME: Move to llvm/Support.
+  void setBackGroundPriority();
+
   /// \brief Print libclang's resource usage to standard error.
   void PrintLibclangResourceUsage(CXTranslationUnit TU);
 }
diff --git a/tools/libclang/CXTranslationUnit.h b/tools/libclang/CXTranslationUnit.h
index b2b1b84037..3ad867ca8b 100644
--- a/tools/libclang/CXTranslationUnit.h
+++ b/tools/libclang/CXTranslationUnit.h
@@ -16,6 +16,7 @@
 
 extern "C" {
 struct CXTranslationUnitImpl {
+  void *CIdx;
   void *TUData;
   void *StringPool;
   void *Diagnostics;
@@ -24,10 +25,11 @@ struct CXTranslationUnitImpl {
 
 namespace clang {
   class ASTUnit;
+  class CIndexer;
 
 namespace cxtu {
 
-CXTranslationUnitImpl *MakeCXTranslationUnit(ASTUnit *TU);
+CXTranslationUnitImpl *MakeCXTranslationUnit(CIndexer *CIdx, ASTUnit *TU);
   
 class CXTUOwner {
   CXTranslationUnitImpl *TU;
diff --git a/tools/libclang/Indexing.cpp b/tools/libclang/Indexing.cpp
index 85b638530f..905569dccd 100644
--- a/tools/libclang/Indexing.cpp
+++ b/tools/libclang/Indexing.cpp
@@ -275,6 +275,9 @@ static void clang_indexSourceFile_Impl(void *UserData) {
 
   CIndexer *CXXIdx = static_cast<CIndexer *>(CIdx);
 
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
+    setBackGroundPriority();
+
   CaptureDiagnosticConsumer *CaptureDiag = new CaptureDiagnosticConsumer();
 
   // Configure the diagnostics.
@@ -351,7 +354,7 @@ static void clang_indexSourceFile_Impl(void *UserData) {
 
   ASTUnit *Unit = ASTUnit::create(CInvok.getPtr(), Diags,
                                   /*CaptureDiagnostics=*/true);
-  OwningPtr<CXTUOwner> CXTU(new CXTUOwner(MakeCXTranslationUnit(Unit)));
+  OwningPtr<CXTUOwner> CXTU(new CXTUOwner(MakeCXTranslationUnit(CXXIdx, Unit)));
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<CXTUOwner>
@@ -502,6 +505,10 @@ static void clang_indexTranslationUnit_Impl(void *UserData) {
   if (!client_index_callbacks || index_callbacks_size == 0)
     return;
 
+  CIndexer *CXXIdx = (CIndexer*)TU->CIdx;
+  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
+    setBackGroundPriority();
+
   IndexerCallbacks CB;
   memset(&CB, 0, sizeof(CB));
   unsigned ClientCBSize = index_callbacks_size < sizeof(CB)
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index afdb0c90bc..21861fb709 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -1,5 +1,7 @@
 clang_CXCursorSet_contains
 clang_CXCursorSet_insert
+clang_CXIndex_getGlobalOptions
+clang_CXIndex_setGlobalOptions
 clang_CXXMethod_isStatic
 clang_CXXMethod_isVirtual
 clang_Cursor_getTranslationUnit