[ObjCARC] Prevent code motion into a catchswitch

A catchswitch must be the only non-phi instruction in its basic block;
attempting to move a retain or release into a catchswitch basic block
will result in invalid IR. Explicitly mark a CFG hazard in this case to
prevent the code motion.

Differential Revision: https://reviews.llvm.org/D46482

llvm-svn: 332430

2 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index db09cc3487a..8d657f8b258 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -1592,6 +1592,7 @@ bool ObjCARCOpt::PairUpRetainsAndReleases(
       assert(It != Retains.end());
       const RRInfo &NewRetainRRI = It->second;
       KnownSafeTD &= NewRetainRRI.KnownSafe;
+      CFGHazardAfflicted |= NewRetainRRI.CFGHazardAfflicted;
       for (Instruction *NewRetainRelease : NewRetainRRI.Calls) {
         auto Jt = Releases.find(NewRetainRelease);
         if (Jt == Releases.end())
diff --git a/llvm/lib/Transforms/ObjCARC/PtrState.cpp b/llvm/lib/Transforms/ObjCARC/PtrState.cpp
index b6c48529de4..8a7b6a74fae 100644
--- a/llvm/lib/Transforms/ObjCARC/PtrState.cpp
+++ b/llvm/lib/Transforms/ObjCARC/PtrState.cpp
@@ -268,6 +268,11 @@ void BottomUpPtrState::HandlePotentialUse(BasicBlock *BB, Instruction *Inst,
     if (isa<InvokeInst>(Inst)) {
       const auto IP = BB->getFirstInsertionPt();
       InsertAfter = IP == BB->end() ? std::prev(BB->end()) : IP;
+      if (isa<CatchSwitchInst>(InsertAfter))
+        // A catchswitch must be the only non-phi instruction in its basic
+        // block, so attempting to insert an instruction into such a block would
+        // produce invalid IR.
+        SetCFGHazardAfflicted(true);
     } else {
       InsertAfter = std::next(Inst->getIterator());
     }