From 1edbd6f3f07176851cb03f7932ff50b9e9619dfb Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Wed, 1 Jun 2011 02:17:11 +0000
Subject: [PATCH] First, do no harm -- even if we can't find a selector for an
 enclosing landing pad, forward llvm.eh.resume calls to it instead of turning
 them invalidly into invokes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132382 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/InlineFunction.cpp | 22 ++++++++++++++----
 test/Transforms/Inline/inline_invoke.ll | 31 +++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index d2fd07aed10..4a829874832 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -214,13 +214,24 @@ BasicBlock *InvokeInliningInfo::getInnerUnwindDest() {
 /// at the end of the given block, as a branch to the inner unwind
 /// block.  Returns true if the call was forwarded.
 bool InvokeInliningInfo::forwardEHResume(CallInst *call, BasicBlock *src) {
+  // First, check whether this is a call to the intrinsic.
   Function *fn = dyn_cast<Function>(call->getCalledValue());
   if (!fn || fn->getName() != "llvm.eh.resume")
     return false;
+  
+  // At this point, we need to return true on all paths, because
+  // otherwise we'll construct an invoke of the intrinsic, which is
+  // not well-formed.
 
-  // If this fails, maybe it should be a fatal error.
+  // Try to find or make an inner unwind dest, which will fail if we
+  // can't find a selector call for the outer unwind dest.
   BasicBlock *dest = getInnerUnwindDest();
-  if (!dest) return false;
+  bool hasSelector = (dest != 0);
+
+  // If we failed, just use the outer unwind dest, dropping the
+  // exception and selector on the floor.
+  if (!hasSelector)
+    dest = OuterUnwindDest;
 
   // Make a branch.
   BranchInst::Create(dest, src);
@@ -228,8 +239,11 @@ bool InvokeInliningInfo::forwardEHResume(CallInst *call, BasicBlock *src) {
   // Update the phis in the destination.  They were inserted in an
   // order which makes this work.
   addIncomingPHIValuesForInto(src, dest);
-  InnerExceptionPHI->addIncoming(call->getArgOperand(0), src);
-  InnerSelectorPHI->addIncoming(call->getArgOperand(1), src);
+
+  if (hasSelector) {
+    InnerExceptionPHI->addIncoming(call->getArgOperand(0), src);
+    InnerSelectorPHI->addIncoming(call->getArgOperand(1), src);
+  }
 
   return true;
 }
diff --git a/test/Transforms/Inline/inline_invoke.ll b/test/Transforms/Inline/inline_invoke.ll
index 110a82823e1..5f657387c21 100644
--- a/test/Transforms/Inline/inline_invoke.ll
+++ b/test/Transforms/Inline/inline_invoke.ll
@@ -4,7 +4,7 @@
 ; by appending selectors and forwarding _Unwind_Resume directly to the
 ; enclosing landing pad.
 
-;; Test 1 - basic functionality.
+;; Test 0 - basic functionality.
 
 %struct.A = type { i8 }
 
@@ -112,7 +112,7 @@ eh.resume:
 ; CHECK-NEXT: call i32 @llvm.eh.typeid.for(
 
 
-;; Test 2 - Correctly handle phis in outer landing pads.
+;; Test 1 - Correctly handle phis in outer landing pads.
 
 define void @test1_out() uwtable ssp {
 entry:
@@ -216,3 +216,30 @@ eh.resume:
 ; CHECK:      call void @use(i32 [[YJ1]])
 
 ; CHECK:      call void @llvm.eh.resume(i8* [[EXNJ1]], i32 [[SELJ1]])
+
+;; Test 2 - Don't make invalid IR for inlines into landing pads without eh.exception calls
+
+define void @test2_out() uwtable ssp {
+entry:
+  invoke void @test0_in()
+          to label %ret unwind label %lpad
+
+ret:
+  ret void
+
+lpad:
+  call void @_ZSt9terminatev()
+  unreachable
+}
+
+; CHECK: define void @test2_out()
+; CHECK:      [[A:%.*]] = alloca %struct.A,
+; CHECK:      [[B:%.*]] = alloca %struct.A,
+; CHECK:      invoke void @_ZN1AC1Ev(%struct.A* [[A]])
+; CHECK-NEXT:   unwind label %[[LPAD:[^\s]+]]
+; CHECK:      invoke void @_ZN1AC1Ev(%struct.A* [[B]])
+; CHECK-NEXT:   unwind label %[[LPAD2:[^\s]+]]
+; CHECK:      invoke void @_ZN1AD1Ev(%struct.A* [[B]])
+; CHECK-NEXT:   unwind label %[[LPAD2]]
+; CHECK:      invoke void @_ZN1AD1Ev(%struct.A* [[A]])
+; CHECK-NEXT:   unwind label %[[LPAD]]