Revamp the SjLj "dispatch setup" intrinsic.

It needed to be moved closer to the setjmp statement, because the code directly
after the setjmp needs to know about values that are on the stack. Also, the
'bitcast' of the function context was causing a dead load. This wouldn't be too
horrible, except that at -O0 it wasn't optimized out, and because it wasn't
using the correct base pointer (if there is a VLA), it would try to access a
value from a garbage address.
<rdar://problem/9130540>

llvm-svn: 128873

2 files changed, 6 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 6785d69..24c325e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4403,7 +4403,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   }
   case Intrinsic::eh_sjlj_dispatch_setup: {
     DAG.setRoot(DAG.getNode(ISD::EH_SJLJ_DISPATCHSETUP, dl, MVT::Other,
-                            getRoot(), getValue(I.getArgOperand(0))));
+                            getRoot()));
     return 0;
   }
 
diff --git a/llvm/lib/CodeGen/SjLjEHPrepare.cpp b/llvm/lib/CodeGen/SjLjEHPrepare.cpp
index 13e1454..aaa8568 100644
--- a/llvm/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/llvm/lib/CodeGen/SjLjEHPrepare.cpp
@@ -442,14 +442,6 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
   BasicBlock *DispatchBlock =
     BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
 
-  // Add a call to dispatch_setup at the start of the dispatch block. This is
-  // expanded to any target-specific setup that needs to be done.
-  Value *SetupArg =
-    CastInst::Create(Instruction::BitCast, FunctionContext,
-                     Type::getInt8PtrTy(F.getContext()), "",
-                     DispatchBlock);
-  CallInst::Create(DispatchSetupFn, SetupArg, "", DispatchBlock);
-
   // Insert a load of the callsite in the dispatch block, and a switch on its
   // value.  By default, we go to a block that just does an unwind (which is the
   // correct action for a standard call).
@@ -524,6 +516,11 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
   Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
                                         "dispatch",
                                         EntryBB->getTerminator());
+
+  // Add a call to dispatch_setup after the setjmp call. This is expanded to any
+  // target-specific setup that needs to be done.
+  CallInst::Create(DispatchSetupFn, "", EntryBB->getTerminator());
+
   // check the return value of the setjmp. non-zero goes to dispatcher.
   Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
                                  ICmpInst::ICMP_EQ, DispatchVal, Zero,