[PATCH] Outline cleanup handlers for native Windows C++ exception handling

[Reid Kleckner]

lgtm


REPOSITORY
  rL LLVM

================
Comment at: lib/CodeGen/WinEHPrepare.cpp:288-292
@@ +287,7 @@
+    //        cleanup.  That will happen after the block analysis is in place.
+    if (LPad->isCleanup()) {
+      CallInst *EHAlloc = nullptr;
+      AllocaInst *IgnoreEHObjPtr = nullptr;
+      bool Outlined = outlineHandler(Cleanup, &F, nullptr, LPad, EHAlloc,
+                                     IgnoreEHObjPtr, FrameVarInfo);
+      if (Outlined) {
----------------
andrew.w.kaylor wrote:
> rnk wrote:
> > I'm not sure we can handle catches inside cleanups this way. Are you planning to switch to a more up front analysis in subsequent changes? I'm thinking of this case:
> >   void g();
> >   struct MyRAII { ~MyRAII(); };
> >   void runs_before_dtor();
> >   void f() {
> >     MyRAII x;
> >     try { g(); }
> >     catch (int) { runs_before_dtor(); }
> >   }
> > 
> > We need to make sure runs_before_dtor() runs first, but I guess we haven't gotten to building eh.actions.
> Yeah, this only handles a single cleanup per landing pad and doesn't handle the case where a block of cleanup code is shared between landing pads.  This is basically here as a place holder to move things along.  I can add a comment explaining that.
> 
> To handle cases like the one you describe I need the block analysis stuff in place.  The actually outlining works the same way except that it gets a specific starting block and has different termination conditions.  I have that working in my sandbox, but it seemed like a bit much to put into this review.
OK, sounds good.

http://reviews.llvm.org/D7865

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