r304212 - [libclang] Allow to suspend a translation unit.

Erik Verbruggen via cfe-commits cfe-commits at lists.llvm.org
Tue May 30 07:25:55 PDT 2017


Author: erikjv
Date: Tue May 30 09:25:54 2017
New Revision: 304212

URL: http://llvm.org/viewvc/llvm-project?rev=304212&view=rev
Log:
[libclang] Allow to suspend a translation unit.

A suspended translation unit uses significantly less memory but on the
other side does not support any other calls than
clang_reparseTranslationUnit to resume it or
clang_disposeTranslationUnit to dispose it completely.

This helps IDEs to reduce the memory footprint. The data that is freed
by a call to clang_suspendTranslationUnit will be re-generated on the
next (re)parse anyway. Used with a preamble, this allows pretty fast
resumption of the translation unit for further use (compared to disposal
of the translation unit and a parse from scratch).

Patch by Nikolai Kosjar!

Modified:
    cfe/trunk/include/clang-c/Index.h
    cfe/trunk/include/clang/Frontend/ASTUnit.h
    cfe/trunk/lib/Frontend/ASTUnit.cpp
    cfe/trunk/tools/c-index-test/c-index-test.c
    cfe/trunk/tools/libclang/CIndex.cpp
    cfe/trunk/tools/libclang/libclang.exports

Modified: cfe/trunk/include/clang-c/Index.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang-c/Index.h?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/include/clang-c/Index.h (original)
+++ cfe/trunk/include/clang-c/Index.h Tue May 30 09:25:54 2017
@@ -32,7 +32,7 @@
  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 40
+#define CINDEX_VERSION_MINOR 41
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
@@ -1419,6 +1419,15 @@ CINDEX_LINKAGE int clang_saveTranslation
                                              unsigned options);
 
 /**
+ * \brief Suspend a translation unit in order to free memory associated with it.
+ *
+ * A suspended translation unit uses significantly less memory but on the other
+ * side does not support any other calls than \c clang_reparseTranslationUnit
+ * to resume it or \c clang_disposeTranslationUnit to dispose it completely.
+ */
+CINDEX_LINKAGE unsigned clang_suspendTranslationUnit(CXTranslationUnit);
+
+/**
  * \brief Destroy the specified CXTranslationUnit object.
  */
 CINDEX_LINKAGE void clang_disposeTranslationUnit(CXTranslationUnit);

Modified: cfe/trunk/include/clang/Frontend/ASTUnit.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/ASTUnit.h?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/ASTUnit.h (original)
+++ cfe/trunk/include/clang/Frontend/ASTUnit.h Tue May 30 09:25:54 2017
@@ -878,6 +878,11 @@ public:
                ArrayRef<RemappedFile> RemappedFiles = None,
                IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
 
+  /// \brief Free data that will be re-generated on the next parse.
+  ///
+  /// Preamble-related data is not affected.
+  void ResetForParse();
+
   /// \brief Perform code completion at the given file, line, and
   /// column within this translation unit.
   ///

Modified: cfe/trunk/lib/Frontend/ASTUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/ASTUnit.cpp?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/ASTUnit.cpp (original)
+++ cfe/trunk/lib/Frontend/ASTUnit.cpp Tue May 30 09:25:54 2017
@@ -1036,8 +1036,6 @@ static void checkAndSanitizeDiags(SmallV
 bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                     std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer,
                     IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
-  SavedMainFileBuffer.reset();
-
   if (!Invocation)
     return true;
 
@@ -1090,17 +1088,11 @@ bool ASTUnit::Parse(std::shared_ptr<PCHC
     Clang->createFileManager();
     FileMgr = &Clang->getFileManager();
   }
-  SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
-                                UserFilesAreVolatile);
-  TheSema.reset();
-  Ctx = nullptr;
-  PP = nullptr;
-  Reader = nullptr;
 
-  // Clear out old caches and data.
-  TopLevelDecls.clear();
-  clearFileLevelDecls();
+  ResetForParse();
 
+  SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
+                                UserFilesAreVolatile);
   if (!OverrideMainBuffer) {
     checkAndRemoveNonDriverDiags(StoredDiagnostics);
     TopLevelDeclsInPreamble.clear();
@@ -2116,6 +2108,19 @@ bool ASTUnit::Reparse(std::shared_ptr<PC
   return Result;
 }
 
+void ASTUnit::ResetForParse() {
+  SavedMainFileBuffer.reset();
+
+  SourceMgr.reset();
+  TheSema.reset();
+  Ctx.reset();
+  PP.reset();
+  Reader.reset();
+
+  TopLevelDecls.clear();
+  clearFileLevelDecls();
+}
+
 //----------------------------------------------------------------------------//
 // Code completion
 //----------------------------------------------------------------------------//

Modified: cfe/trunk/tools/c-index-test/c-index-test.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/c-index-test/c-index-test.c?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/tools/c-index-test/c-index-test.c (original)
+++ cfe/trunk/tools/c-index-test/c-index-test.c Tue May 30 09:25:54 2017
@@ -1742,6 +1742,8 @@ int perform_test_load_source(int argc, c
       return -1;
 
     if (Repeats > 1) {
+      clang_suspendTranslationUnit(TU);
+
       Err = clang_reparseTranslationUnit(TU, num_unsaved_files, unsaved_files,
                                          clang_defaultReparseOptions(TU));
       if (Err != CXError_Success) {

Modified: cfe/trunk/tools/libclang/CIndex.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/libclang/CIndex.cpp?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/tools/libclang/CIndex.cpp (original)
+++ cfe/trunk/tools/libclang/CIndex.cpp Tue May 30 09:25:54 2017
@@ -3918,6 +3918,20 @@ void clang_disposeTranslationUnit(CXTran
   }
 }
 
+unsigned clang_suspendTranslationUnit(CXTranslationUnit CTUnit) {
+  if (CTUnit) {
+    ASTUnit *Unit = cxtu::getASTUnit(CTUnit);
+
+    if (Unit && Unit->isUnsafeToFree())
+      return false;
+
+    Unit->ResetForParse();
+    return true;
+  }
+
+  return false;
+}
+
 unsigned clang_defaultReparseOptions(CXTranslationUnit TU) {
   return CXReparse_None;
 }

Modified: cfe/trunk/tools/libclang/libclang.exports
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/libclang/libclang.exports?rev=304212&r1=304211&r2=304212&view=diff
==============================================================================
--- cfe/trunk/tools/libclang/libclang.exports (original)
+++ cfe/trunk/tools/libclang/libclang.exports Tue May 30 09:25:54 2017
@@ -305,6 +305,7 @@ clang_remap_getFilenames
 clang_remap_getNumFiles
 clang_reparseTranslationUnit
 clang_saveTranslationUnit
+clang_suspendTranslationUnit
 clang_sortCodeCompletionResults
 clang_toggleCrashRecovery
 clang_tokenize




More information about the cfe-commits mailing list