[clang] Change ordering of PreableCallbacks to make sure PP can be referenced in...

Currently, BeforeExecute is called before BeginSourceFile which does not allow
using PP in the callbacks. Change the ordering to ensure it is possible.
This is a prerequisite for D114370.

Originated from a discussion with @kadircet.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D114525

diff --git a/clang/include/clang/Frontend/PrecompiledPreamble.h b/clang/include/clang/Frontend/PrecompiledPreamble.h
index bb7fd97..dacbffe 100644 (file)
--- a/clang/include/clang/Frontend/PrecompiledPreamble.h
+++ b/clang/include/clang/Frontend/PrecompiledPreamble.h
@@ -274,7 +274,7 @@ class PreambleCallbacks {
 public:
   virtual ~PreambleCallbacks() = default;
 
-  /// Called before FrontendAction::BeginSourceFile.
+  /// Called before FrontendAction::Execute.
   /// Can be used to store references to various CompilerInstance fields
   /// (e.g. SourceManager) that may be interesting to the consumers of other
   /// callbacks.
@@ -291,7 +291,7 @@ public:
   /// used instead, but having only this method allows a simpler API.
   virtual void HandleTopLevelDecl(DeclGroupRef DG);
   /// Creates wrapper class for PPCallbacks so we can also process information
-  /// about includes that are inside of a preamble
+  /// about includes that are inside of a preamble. Called after BeforeExecute.
   virtual std::unique_ptr<PPCallbacks> createPPCallbacks();
   /// The returned CommentHandler will be added to the preprocessor if not null.
   virtual CommentHandler *getCommentHandler();

diff --git a/clang/lib/Frontend/PrecompiledPreamble.cpp b/clang/lib/Frontend/PrecompiledPreamble.cpp
index af82ab3..8aa80a4 100644 (file)
--- a/clang/lib/Frontend/PrecompiledPreamble.cpp
+++ b/clang/lib/Frontend/PrecompiledPreamble.cpp
@@ -412,10 +412,13 @@ llvm::ErrorOr<PrecompiledPreamble> PrecompiledPreamble::Build(
   std::unique_ptr<PrecompilePreambleAction> Act;
   Act.reset(new PrecompilePreambleAction(
       StoreInMemory ? &Storage.asMemory().Data : nullptr, Callbacks));
-  Callbacks.BeforeExecute(*Clang);
   if (!Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0]))
     return BuildPreambleError::BeginSourceFileFailed;
 
+  // Performed after BeginSourceFile to ensure Clang->Preprocessor can be
+  // referenced in the callback.
+  Callbacks.BeforeExecute(*Clang);
+
   std::unique_ptr<PPCallbacks> DelegatedPPCallbacks =
       Callbacks.createPPCallbacks();
   if (DelegatedPPCallbacks)