[libclang] Allow skipping function bodies in preamble only

Second attempt. Fix line endings and warning.

As an addition to CXTranslationUnit_SkipFunctionBodies, provide the
new option CXTranslationUnit_LimitSkipFunctionBodiesToPreamble,
which constraints the skipping of functions bodies to the preamble
only. Function bodies in the main file are not affected if this
option is set.

Skipping function bodies only in the preamble is what clangd already
does and the introduced flag implements it for libclang clients.

Patch by Nikolai Kosjar.

Differential Revision: https://reviews.llvm.org/D45815

llvm-svn: 332587

7 files changed, 59 insertions, 10 deletions

diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index 3fee13a40b4..ff14d6e729a 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -1324,7 +1324,15 @@ enum CXTranslationUnit_Flags {
   /**
    * Sets the preprocessor in a mode for parsing a single file only.
    */
-  CXTranslationUnit_SingleFileParse = 0x400
+  CXTranslationUnit_SingleFileParse = 0x400,
+
+  /**
+   * \brief Used in combination with CXTranslationUnit_SkipFunctionBodies to
+   * constrain the skipping of function bodies to the preamble.
+   *
+   * The function bodies of the main file are not skipped.
+   */
+  CXTranslationUnit_LimitSkipFunctionBodiesToPreamble = 0x800
 };
 
 /**
diff --git a/clang/include/clang/Frontend/ASTUnit.h b/clang/include/clang/Frontend/ASTUnit.h
index af67dd1aedc..35cacee57f7 100644
--- a/clang/include/clang/Frontend/ASTUnit.h
+++ b/clang/include/clang/Frontend/ASTUnit.h
@@ -81,6 +81,9 @@ class FileSystem;
 
 } // namespace vfs
 
+/// \brief Enumerates the available scopes for skipping function bodies.
+enum class SkipFunctionBodiesScope { None, Preamble, PreambleAndMainFile };
+
 /// Utility class for loading a ASTContext from an AST file.
 class ASTUnit {
 public:
@@ -348,6 +351,9 @@ private:
   /// inconsistent state, and is not safe to free.
   unsigned UnsafeToFree : 1;
 
+  /// \brief Enumerator specifying the scope for skipping function bodies.
+  SkipFunctionBodiesScope SkipFunctionBodies = SkipFunctionBodiesScope::None;
+
   /// Cache any "global" code-completion results, so that we can avoid
   /// recomputing them with each completion.
   void CacheCodeCompletionResults();
@@ -363,7 +369,7 @@ private:
 
   std::unique_ptr<llvm::MemoryBuffer> getMainBufferWithPrecompiledPreamble(
       std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-      const CompilerInvocation &PreambleInvocationIn,
+      CompilerInvocation &PreambleInvocationIn,
       IntrusiveRefCntPtr<vfs::FileSystem> VFS, bool AllowRebuild = true,
       unsigned MaxLines = 0);
   void RealizeTopLevelDeclsFromPreamble();
@@ -801,9 +807,11 @@ public:
       TranslationUnitKind TUKind = TU_Complete,
       bool CacheCodeCompletionResults = false,
       bool IncludeBriefCommentsInCodeCompletion = false,
-      bool AllowPCHWithCompilerErrors = false, bool SkipFunctionBodies = false,
-      bool SingleFileParse = false,
-      bool UserFilesAreVolatile = false, bool ForSerialization = false,
+      bool AllowPCHWithCompilerErrors = false,
+      SkipFunctionBodiesScope SkipFunctionBodies =
+          SkipFunctionBodiesScope::None,
+      bool SingleFileParse = false, bool UserFilesAreVolatile = false,
+      bool ForSerialization = false,
       llvm::Optional<StringRef> ModuleFormat = llvm::None,
       std::unique_ptr<ASTUnit> *ErrAST = nullptr,
       IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 9b672d97551..2214d827455 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1271,7 +1271,7 @@ makeStandaloneDiagnostic(const LangOptions &LangOpts,
 std::unique_ptr<llvm::MemoryBuffer>
 ASTUnit::getMainBufferWithPrecompiledPreamble(
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-    const CompilerInvocation &PreambleInvocationIn,
+    CompilerInvocation &PreambleInvocationIn,
     IntrusiveRefCntPtr<vfs::FileSystem> VFS, bool AllowRebuild,
     unsigned MaxLines) {
   auto MainFilePath =
@@ -1338,9 +1338,18 @@ ASTUnit::getMainBufferWithPrecompiledPreamble(
     SimpleTimer PreambleTimer(WantTiming);
     PreambleTimer.setOutput("Precompiling preamble");
 
+    const bool PreviousSkipFunctionBodies =
+        PreambleInvocationIn.getFrontendOpts().SkipFunctionBodies;
+    if (SkipFunctionBodies == SkipFunctionBodiesScope::Preamble)
+      PreambleInvocationIn.getFrontendOpts().SkipFunctionBodies = true;
+
     llvm::ErrorOr<PrecompiledPreamble> NewPreamble = PrecompiledPreamble::Build(
         PreambleInvocationIn, MainFileBuffer.get(), Bounds, *Diagnostics, VFS,
         PCHContainerOps, /*StoreInMemory=*/false, Callbacks);
+
+    PreambleInvocationIn.getFrontendOpts().SkipFunctionBodies =
+        PreviousSkipFunctionBodies;
+
     if (NewPreamble) {
       Preamble = std::move(*NewPreamble);
       PreambleRebuildCounter = 1;
@@ -1691,7 +1700,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     ArrayRef<RemappedFile> RemappedFiles, bool RemappedFilesKeepOriginalName,
     unsigned PrecompilePreambleAfterNParses, TranslationUnitKind TUKind,
     bool CacheCodeCompletionResults, bool IncludeBriefCommentsInCodeCompletion,
-    bool AllowPCHWithCompilerErrors, bool SkipFunctionBodies,
+    bool AllowPCHWithCompilerErrors, SkipFunctionBodiesScope SkipFunctionBodies,
     bool SingleFileParse, bool UserFilesAreVolatile, bool ForSerialization,
     llvm::Optional<StringRef> ModuleFormat, std::unique_ptr<ASTUnit> *ErrAST,
     IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
@@ -1724,7 +1733,8 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   // Override the resources path.
   CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
 
-  CI->getFrontendOpts().SkipFunctionBodies = SkipFunctionBodies;
+  CI->getFrontendOpts().SkipFunctionBodies =
+      SkipFunctionBodies == SkipFunctionBodiesScope::PreambleAndMainFile;
 
   if (ModuleFormat)
     CI->getHeaderSearchOpts().ModuleFormat = ModuleFormat.getValue();
@@ -1750,6 +1760,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     = IncludeBriefCommentsInCodeCompletion;
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->Invocation = CI;
+  AST->SkipFunctionBodies = SkipFunctionBodies;
   if (ForSerialization)
     AST->WriterData.reset(new ASTWriterData(*AST->PCMCache));
   // Zero out now to ease cleanup during crash recovery.
diff --git a/clang/test/Parser/skip-function-bodies.h b/clang/test/Parser/skip-function-bodies.h
new file mode 100644
index 00000000000..2d1a4c009ca
--- /dev/null
+++ b/clang/test/Parser/skip-function-bodies.h
@@ -0,0 +1,3 @@
+int header1(int t) {
+  return t;
+}
diff --git a/clang/test/Parser/skip-function-bodies.mm b/clang/test/Parser/skip-function-bodies.mm
index e5b7b2adf83..646730ee6c7 100644
--- a/clang/test/Parser/skip-function-bodies.mm
+++ b/clang/test/Parser/skip-function-bodies.mm
@@ -1,4 +1,4 @@
-// RUN: env CINDEXTEST_SKIP_FUNCTION_BODIES=1 c-index-test -test-load-source all %s | FileCheck %s
+#include "skip-function-bodies.h"
 
 class A {
   class B {};
@@ -27,6 +27,7 @@ void J() {
   class K {};
 }
 
+// RUN: env CINDEXTEST_SKIP_FUNCTION_BODIES=1 c-index-test -test-load-source all %s | FileCheck %s
 // CHECK: skip-function-bodies.mm:3:7: ClassDecl=A:3:7 (Definition) Extent=[3:1 - 14:2]
 // CHECK: skip-function-bodies.mm:4:9: ClassDecl=B:4:9 (Definition) Extent=[4:3 - 4:13]
 // CHECK: skip-function-bodies.mm:6:1: CXXAccessSpecifier=:6:1 (Definition) Extent=[6:1 - 6:8]
@@ -43,3 +44,13 @@ void J() {
 // CHECK-NOT: skip-function-bodies.mm:21:11: TypeRef=class A:3:7 Extent=[21:11 - 21:12]
 // CHECK: skip-function-bodies.mm:26:6: FunctionDecl=J:26:6 Extent=[26:1 - 26:9]
 // CHECK-NOT: skip-function-bodies.mm:27:9: ClassDecl=K:27:9 (Definition) Extent=[27:3 - 27:13]
+
+// RUN: env CINDEXTEST_EDITING=1 \
+// RUN:  CINDEXTEST_CREATE_PREAMBLE_ON_FIRST_PARSE=1 \
+// RUN:  CINDEXTEST_SKIP_FUNCTION_BODIES=1 \
+// RUN:  CINDEXTEST_LIMIT_SKIP_FUNCTION_BODIES_TO_PREAMBLE=1 \
+// RUN:  c-index-test -test-load-source all %s | FileCheck -check-prefix=CHECK-PREAMBLE %s
+// CHECK-PREAMBLE: skip-function-bodies.h:1:5: FunctionDecl=header1:1:5 Extent=[1:1 - 1:19]
+// CHECK-PREAMBLE-NOT: skip-function-bodies.h:2:3: ReturnStmt= Extent=[2:3 - 2:11]
+// CHECK-PREAMBLE: skip-function-bodies.mm:8:12: StructDecl=C:8:12 (Definition) Extent=[8:5 - 10:6]
+// CHECK-PREAMBLE: skip-function-bodies.mm:9:12: CXXMethod=d:9:12 (Definition) Extent=[9:7 - 9:18]
diff --git a/clang/tools/c-index-test/c-index-test.c b/clang/tools/c-index-test/c-index-test.c
index d57ac4f9f6c..e86a20b55b6 100644
--- a/clang/tools/c-index-test/c-index-test.c
+++ b/clang/tools/c-index-test/c-index-test.c
@@ -82,6 +82,8 @@ static unsigned getDefaultParsingOptions() {
     options |= CXTranslationUnit_CreatePreambleOnFirstParse;
   if (getenv("CINDEXTEST_KEEP_GOING"))
     options |= CXTranslationUnit_KeepGoing;
+  if (getenv("CINDEXTEST_LIMIT_SKIP_FUNCTION_BODIES_TO_PREAMBLE"))
+    options |= CXTranslationUnit_LimitSkipFunctionBodiesToPreamble;
 
   return options;
 }
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index c348506545d..32f6ca994bb 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3380,9 +3380,15 @@ clang_parseTranslationUnit_Impl(CXIndex CIdx, const char *source_filename,
     = options & CXTranslationUnit_CacheCompletionResults;
   bool IncludeBriefCommentsInCodeCompletion
     = options & CXTranslationUnit_IncludeBriefCommentsInCodeCompletion;
-  bool SkipFunctionBodies = options & CXTranslationUnit_SkipFunctionBodies;
   bool SingleFileParse = options & CXTranslationUnit_SingleFileParse;
   bool ForSerialization = options & CXTranslationUnit_ForSerialization;
+  SkipFunctionBodiesScope SkipFunctionBodies = SkipFunctionBodiesScope::None;
+  if (options & CXTranslationUnit_SkipFunctionBodies) {
+    SkipFunctionBodies =
+        (options & CXTranslationUnit_LimitSkipFunctionBodiesToPreamble)
+            ? SkipFunctionBodiesScope::Preamble
+            : SkipFunctionBodiesScope::PreambleAndMainFile;
+  }
 
   // Configure the diagnostics.
   IntrusiveRefCntPtr<DiagnosticsEngine>