[clang-cl, PCH] Support for /Yc and /Yu without filename and #pragma hdrstop

With clang-cl, when the user specifies /Yc or /Yu without a filename
the compiler uses a #pragma hdrstop in the main source file to
determine the end of the PCH. If a header is specified with /Yc or
/Yu #pragma hdrstop has no effect.

The optional #pragma hdrstop filename argument is not yet supported.

Differential Revision: https://reviews.llvm.org/D51391



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341963 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 26 insertions, 4 deletions

diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index cc2d59b133..02ea80aa3f 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -726,6 +726,9 @@ private:
   /// The file ID for the PCH through header.
   FileID PCHThroughHeaderFileID;
 
+  /// Whether tokens are being skipped until a #pragma hdrstop is seen.
+  bool SkippingUntilPragmaHdrStop = false;
+
   /// Whether tokens are being skipped until the through header is seen.
   bool SkippingUntilPCHThroughHeader = false;
 
@@ -1168,11 +1171,19 @@ public:
   /// True if using a PCH with a through header.
   bool usingPCHWithThroughHeader();
 
-  /// Skip tokens until after the #include of the through header.
-  void SkipTokensUntilPCHThroughHeader();
+  /// True if creating a PCH with a #pragma hdrstop.
+  bool creatingPCHWithPragmaHdrStop();
+
+  /// True if using a PCH with a #pragma hdrstop.
+  bool usingPCHWithPragmaHdrStop();
+
+  /// Skip tokens until after the #include of the through header or
+  /// until after a #pragma hdrstop.
+  void SkipTokensWhileUsingPCH();
 
-  /// Process directives while skipping until the through header is found.
-  void HandleSkippedThroughHeaderDirective(Token &Result,
+  /// Process directives while skipping until the through header or
+  /// #pragma hdrstop is found.
+  void HandleSkippedDirectiveWhileUsingPCH(Token &Result,
                                            SourceLocation HashLoc);
 
   /// Enter the specified FileID as the main source file,
@@ -2203,6 +2214,7 @@ public:
   void HandlePragmaPopMacro(Token &Tok);
   void HandlePragmaIncludeAlias(Token &Tok);
   void HandlePragmaModuleBuild(Token &Tok);
+  void HandlePragmaHdrstop(Token &Tok);
   IdentifierInfo *ParsePragmaPushOrPopMacro(Token &Tok);
 
   // Return true and store the first token only if any CommentHandler
diff --git a/include/clang/Lex/PreprocessorOptions.h b/include/clang/Lex/PreprocessorOptions.h
index 5134aeaa6a..6b3823911c 100644
--- a/include/clang/Lex/PreprocessorOptions.h
+++ b/include/clang/Lex/PreprocessorOptions.h
@@ -54,6 +54,16 @@ public:
   /// definitions and expansions.
   bool DetailedRecord = false;
 
+  /// When true, we are creating or using a PCH where a #pragma hdrstop is
+  /// expected to indicate the beginning or end of the PCH.
+  bool PCHWithHdrStop = false;
+
+  /// When true, we are creating a PCH or creating the PCH object while
+  /// expecting a #pragma hdrstop to separate the two.  Allow for a
+  /// missing #pragma hdrstop, which generates a PCH for the whole file,
+  /// and creates an empty PCH object.
+  bool PCHWithHdrStopCreate = false;
+
   /// If non-empty, the filename used in an #include directive in the primary
   /// source file (or command-line preinclude) that is used to implement
   /// MSVC-style precompiled headers. When creating a PCH, after the #include