[preprocessor] Add an opportunity to retain excluded conditional blocks

It is handy for clang tooling, for instance, in source to source transformation.

Reviewers: vpykhtin (Valery Pykhtin), erichkeane (Erich Keane)

Subscribers: rsmith (Richard Smith), akyrtzi (Argyrios Kyrtzidis)

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66597

llvm-svn: 370123

8 files changed, 194 insertions, 6 deletions

diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index 74badac740b..bdce233ce8b 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -1356,7 +1356,12 @@ enum CXTranslationUnit_Flags {
    * the case where these warnings are not of interest, as for an IDE for
    * example, which typically shows only the diagnostics in the main file.
    */
-  CXTranslationUnit_IgnoreNonErrorsFromIncludedFiles = 0x4000
+  CXTranslationUnit_IgnoreNonErrorsFromIncludedFiles = 0x4000,
+
+  /**
+   * Tells the preprocessor not to skip excluded conditional blocks.
+   */
+  CXTranslationUnit_RetainExcludedConditionalBlocks = 0x8000,
 };
 
 /**
diff --git a/clang/include/clang/Frontend/ASTUnit.h b/clang/include/clang/Frontend/ASTUnit.h
index 08cc91946eb..a36655150d4 100644
--- a/clang/include/clang/Frontend/ASTUnit.h
+++ b/clang/include/clang/Frontend/ASTUnit.h
@@ -832,6 +832,7 @@ public:
           SkipFunctionBodiesScope::None,
       bool SingleFileParse = false, bool UserFilesAreVolatile = false,
       bool ForSerialization = false,
+      bool RetainExcludedConditionalBlocks = false,
       llvm::Optional<StringRef> ModuleFormat = llvm::None,
       std::unique_ptr<ASTUnit> *ErrAST = nullptr,
       IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
diff --git a/clang/include/clang/Lex/PreprocessorOptions.h b/clang/include/clang/Lex/PreprocessorOptions.h
index 1480548c7fb..8824f0a51d0 100644
--- a/clang/include/clang/Lex/PreprocessorOptions.h
+++ b/clang/include/clang/Lex/PreprocessorOptions.h
@@ -142,6 +142,9 @@ public:
   /// compiler invocation and its buffers will be reused.
   bool RetainRemappedFileBuffers = false;
 
+  /// When enabled, excluded conditional blocks retain in the main file.
+  bool RetainExcludedConditionalBlocks = false;
+
   /// The Objective-C++ ARC standard library that we should support,
   /// by providing appropriate definitions to retrofit the standard library
   /// with support for lifetime-qualified pointers.
@@ -201,6 +204,7 @@ public:
     RetainRemappedFileBuffers = true;
     PrecompiledPreambleBytes.first = 0;
     PrecompiledPreambleBytes.second = false;
+    RetainExcludedConditionalBlocks = false;
   }
 };
 
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index ac6e6b6048e..35348ffe13b 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1735,6 +1735,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     bool CacheCodeCompletionResults, bool IncludeBriefCommentsInCodeCompletion,
     bool AllowPCHWithCompilerErrors, SkipFunctionBodiesScope SkipFunctionBodies,
     bool SingleFileParse, bool UserFilesAreVolatile, bool ForSerialization,
+    bool RetainExcludedConditionalBlocks,
     llvm::Optional<StringRef> ModuleFormat, std::unique_ptr<ASTUnit> *ErrAST,
     IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   assert(Diags.get() && "no DiagnosticsEngine was provided");
@@ -1762,6 +1763,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   PPOpts.RemappedFilesKeepOriginalName = RemappedFilesKeepOriginalName;
   PPOpts.AllowPCHWithCompilerErrors = AllowPCHWithCompilerErrors;
   PPOpts.SingleFileParseMode = SingleFileParse;
+  PPOpts.RetainExcludedConditionalBlocks = RetainExcludedConditionalBlocks;
 
   // Override the resources path.
   CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 5eac1da115c..525f95b96e0 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -2855,6 +2855,9 @@ void Preprocessor::HandleIfdefDirective(Token &Result,
       Callbacks->Ifdef(DirectiveTok.getLocation(), MacroNameTok, MD);
   }
 
+  bool RetainExcludedCB = PPOpts->RetainExcludedConditionalBlocks &&
+    getSourceManager().isInMainFile(DirectiveTok.getLocation());
+
   // Should we include the stuff contained by this directive?
   if (PPOpts->SingleFileParseMode && !MI) {
     // In 'single-file-parse mode' undefined identifiers trigger parsing of all
@@ -2862,7 +2865,7 @@ void Preprocessor::HandleIfdefDirective(Token &Result,
     CurPPLexer->pushConditionalLevel(DirectiveTok.getLocation(),
                                      /*wasskip*/false, /*foundnonskip*/false,
                                      /*foundelse*/false);
-  } else if (!MI == isIfndef) {
+  } else if (!MI == isIfndef || RetainExcludedCB) {
     // Yes, remember that we are inside a conditional, then lex the next token.
     CurPPLexer->pushConditionalLevel(DirectiveTok.getLocation(),
                                      /*wasskip*/false, /*foundnonskip*/true,
@@ -2903,13 +2906,16 @@ void Preprocessor::HandleIfDirective(Token &IfToken,
         IfToken.getLocation(), DER.ExprRange,
         (ConditionalTrue ? PPCallbacks::CVK_True : PPCallbacks::CVK_False));
 
+  bool RetainExcludedCB = PPOpts->RetainExcludedConditionalBlocks &&
+    getSourceManager().isInMainFile(IfToken.getLocation());
+
   // Should we include the stuff contained by this directive?
   if (PPOpts->SingleFileParseMode && DER.IncludedUndefinedIds) {
     // In 'single-file-parse mode' undefined identifiers trigger parsing of all
     // the directive blocks.
     CurPPLexer->pushConditionalLevel(IfToken.getLocation(), /*wasskip*/false,
                                      /*foundnonskip*/false, /*foundelse*/false);
-  } else if (ConditionalTrue) {
+  } else if (ConditionalTrue || RetainExcludedCB) {
     // Yes, remember that we are inside a conditional, then lex the next token.
     CurPPLexer->pushConditionalLevel(IfToken.getLocation(), /*wasskip*/false,
                                    /*foundnonskip*/true, /*foundelse*/false);
@@ -2971,7 +2977,10 @@ void Preprocessor::HandleElseDirective(Token &Result, const Token &HashToken) {
   if (Callbacks)
     Callbacks->Else(Result.getLocation(), CI.IfLoc);
 
-  if (PPOpts->SingleFileParseMode && !CI.FoundNonSkip) {
+  bool RetainExcludedCB = PPOpts->RetainExcludedConditionalBlocks &&
+    getSourceManager().isInMainFile(Result.getLocation());
+
+  if ((PPOpts->SingleFileParseMode && !CI.FoundNonSkip) || RetainExcludedCB) {
     // In 'single-file-parse mode' undefined identifiers trigger parsing of all
     // the directive blocks.
     CurPPLexer->pushConditionalLevel(CI.IfLoc, /*wasskip*/false,
@@ -3013,7 +3022,10 @@ void Preprocessor::HandleElifDirective(Token &ElifToken,
     Callbacks->Elif(ElifToken.getLocation(), ConditionRange,
                     PPCallbacks::CVK_NotEvaluated, CI.IfLoc);
 
-  if (PPOpts->SingleFileParseMode && !CI.FoundNonSkip) {
+  bool RetainExcludedCB = PPOpts->RetainExcludedConditionalBlocks &&
+    getSourceManager().isInMainFile(ElifToken.getLocation());
+
+  if ((PPOpts->SingleFileParseMode && !CI.FoundNonSkip) || RetainExcludedCB) {
     // In 'single-file-parse mode' undefined identifiers trigger parsing of all
     // the directive blocks.
     CurPPLexer->pushConditionalLevel(ElifToken.getLocation(), /*wasskip*/false,
diff --git a/clang/test/Index/retain-excluded-conditional-blocks.m b/clang/test/Index/retain-excluded-conditional-blocks.m
new file mode 100644
index 00000000000..ebfc7c5723d
--- /dev/null
+++ b/clang/test/Index/retain-excluded-conditional-blocks.m
@@ -0,0 +1,132 @@
+// RUN: c-index-test -retain-excluded-conditional-blocks %s | FileCheck %s
+
+#include <stdint.h>
+
+// CHECK: TypedefDecl=intptr_t
+
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=MyCls
+@interface MyCls
+// CHECK: [[@LINE+1]]:8: ObjCInstanceMethodDecl=some_meth
+-(void)some_meth;
+@end
+
+#if 1
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test1
+@interface Test1 @end
+#else
+// CHECK: [[@LINE+1]]:12:
+@interface Test2 @end
+#endif
+
+#if 0
+// CHECK: [[@LINE+1]]:12:
+@interface Test3 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test4
+@interface Test4 @end
+#endif
+
+#if SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test5
+@interface Test5 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test6
+@interface Test6 @end
+#endif
+
+#define SOMETHING_DEFINED 1
+#if SOMETHING_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test7
+@interface Test7 @end
+#else
+// CHECK: [[@LINE+1]]:12:
+@interface Test8 @end
+#endif
+
+#if defined(SOMETHING_NOT_DEFINED)
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test9
+@interface Test9 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test10
+@interface Test10 @end
+#endif
+
+#if defined(SOMETHING_DEFINED)
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test11
+@interface Test11 @end
+#else
+// CHECK: [[@LINE+1]]:12:
+@interface Test12 @end
+#endif
+
+#if SOMETHING_NOT_DEFINED1
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test13
+@interface Test13 @end
+#elif SOMETHING_NOT_DEFINED2
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test14
+@interface Test14 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test15
+@interface Test15 @end
+#endif
+
+#ifdef SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test19
+@interface Test19 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test20
+@interface Test20 @end
+#endif
+
+#ifdef SOMETHING_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test21
+@interface Test21 @end
+#else
+// CHECK: [[@LINE+1]]:12:
+@interface Test22 @end
+#endif
+
+#ifndef SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test23
+@interface Test23 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test24
+@interface Test24 @end
+#endif
+
+#ifndef SOMETHING_DEFINED
+// CHECK: [[@LINE+1]]:12:
+@interface Test25 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test26
+@interface Test26 @end
+#endif
+
+#if 1 < SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test27
+@interface Test27 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test28
+@interface Test28 @end
+#endif
+
+#if SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test29
+@interface Test29 @end
+#endif
+
+#ifdef SOMETHING_NOT_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test30
+@interface Test30 @end
+#endif
+
+#ifdef SOMETHING_DEFINED
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test31
+@interface Test31 @end
+#elif !defined(SOMETHING_NOT_DEFINED)
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test32
+@interface Test32 @end
+#else
+// CHECK: [[@LINE+1]]:12: ObjCInterfaceDecl=Test33
+@interface Test33 @end
+#endif
diff --git a/clang/tools/c-index-test/c-index-test.c b/clang/tools/c-index-test/c-index-test.c
index 33751714b84..dc7e449a207 100644
--- a/clang/tools/c-index-test/c-index-test.c
+++ b/clang/tools/c-index-test/c-index-test.c
@@ -2181,6 +2181,34 @@ static int perform_single_file_parse(const char *filename) {
   return result;
 }
 
+static int perform_file_retain_excluded_cb(const char *filename) {
+  CXIndex Idx;
+  CXTranslationUnit TU;
+  enum CXErrorCode Err;
+  int result;
+
+  Idx = clang_createIndex(/* excludeDeclsFromPCH */1,
+                          /* displayDiagnostics=*/1);
+
+  Err = clang_parseTranslationUnit2(Idx, filename,
+                                    /*command_line_args=*/NULL,
+                                    /*num_command_line_args=*/0,
+                                    /*unsaved_files=*/NULL,
+                                    /*num_unsaved_files=*/0,
+                                    CXTranslationUnit_RetainExcludedConditionalBlocks, &TU);
+  if (Err != CXError_Success) {
+    fprintf(stderr, "Unable to load translation unit!\n");
+    describeLibclangFailure(Err);
+    clang_disposeIndex(Idx);
+    return 1;
+  }
+
+  result = perform_test_load(Idx, TU, /*filter=*/"all", /*prefix=*/NULL, FilteredPrintingVisitor, /*PostVisit=*/NULL,
+                             /*CommentSchemaFile=*/NULL);
+  clang_disposeIndex(Idx);
+  return result;
+}
+
 /******************************************************************************/
 /* Logic for testing clang_getCursor().                                       */
 /******************************************************************************/
@@ -4849,6 +4877,8 @@ int cindextest_main(int argc, const char **argv) {
   }
   else if (argc >= 3 && strcmp(argv[1], "-single-file-parse") == 0)
     return perform_single_file_parse(argv[2]);
+  else if (argc >= 3 && strcmp(argv[1], "-retain-excluded-conditional-blocks") == 0)
+    return perform_file_retain_excluded_cb(argv[2]);
   else if (argc >= 4 && strcmp(argv[1], "-test-file-scan") == 0)
     return perform_file_scan(argv[2], argv[3],
                              argc >= 5 ? argv[4] : 0);
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 344d6f36d1f..61b60e2bf88 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3417,6 +3417,8 @@ clang_parseTranslationUnit_Impl(CXIndex CIdx, const char *source_filename,
     = options & CXTranslationUnit_IncludeBriefCommentsInCodeCompletion;
   bool SingleFileParse = options & CXTranslationUnit_SingleFileParse;
   bool ForSerialization = options & CXTranslationUnit_ForSerialization;
+  bool RetainExcludedCB = options &
+    CXTranslationUnit_RetainExcludedConditionalBlocks;
   SkipFunctionBodiesScope SkipFunctionBodies = SkipFunctionBodiesScope::None;
   if (options & CXTranslationUnit_SkipFunctionBodies) {
     SkipFunctionBodies =
@@ -3517,7 +3519,7 @@ clang_parseTranslationUnit_Impl(CXIndex CIdx, const char *source_filename,
       /*RemappedFilesKeepOriginalName=*/true, PrecompilePreambleAfterNParses,
       TUKind, CacheCodeCompletionResults, IncludeBriefCommentsInCodeCompletion,
       /*AllowPCHWithCompilerErrors=*/true, SkipFunctionBodies, SingleFileParse,
-      /*UserFilesAreVolatile=*/true, ForSerialization,
+      /*UserFilesAreVolatile=*/true, ForSerialization, RetainExcludedCB,
       CXXIdx->getPCHContainerOperations()->getRawReader().getFormat(),
       &ErrUnit));