[llvm] r262679 - Fix a use-after-free bug introduced in r262636

[Easwaran Raman via llvm-commits]

Author: eraman
Date: Thu Mar  3 18:44:01 2016
New Revision: 262679

URL: http://llvm.org/viewvc/llvm-project?rev=262679&view=rev
Log:
Fix a use-after-free bug introduced in r262636


Modified:
    llvm/trunk/include/llvm/Transforms/Utils/Cloning.h
    llvm/trunk/lib/Transforms/IPO/Inliner.cpp
    llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp

Modified: llvm/trunk/include/llvm/Transforms/Utils/Cloning.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/Cloning.h?rev=262679&r1=262678&r2=262679&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/Cloning.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/Cloning.h Thu Mar  3 18:44:01 2016
@@ -189,7 +189,7 @@ public:
   explicit InlineFunctionInfo(CallGraph *cg = nullptr,
                               AssumptionCacheTracker *ACT = nullptr,
                               BlockCloningFunctor Ftor = nullptr)
-      : CG(cg), ACT(ACT), Ftor(Ftor) {}
+      : CG(cg), ACT(ACT), Ftor(Ftor), CallSuccessorBlockDeleted(false) {}
 
   /// CG - If non-null, InlineFunction will update the callgraph to reflect the
   /// changes it makes.
@@ -198,6 +198,10 @@ public:
   // Functor that is invoked when a block is cloned into the new function.
   BlockCloningFunctor Ftor;
 
+  /// CallSuccessorBlockDeleted - whether the block immediately following the
+  /// call has been deleted during inlining
+  bool CallSuccessorBlockDeleted;
+
   /// StaticAllocas - InlineFunction fills this in with all static allocas that
   /// get copied into the caller.
   SmallVector<AllocaInst *, 4> StaticAllocas;

Modified: llvm/trunk/lib/Transforms/IPO/Inliner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/Inliner.cpp?rev=262679&r1=262678&r2=262679&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/Inliner.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/Inliner.cpp Thu Mar  3 18:44:01 2016
@@ -580,11 +580,13 @@ bool Inliner::runOnSCC(CallGraphSCC &SCC
           continue;
         }
         updateEntryCount(CallSiteBlock, Callee);
-        // The instruction following the call is part of a new basic block
-        // created during the inlining process. This does not have an entry in
-        // the BFI. We create an entry by copying the frequency of the original
-        // block containing the call.
-        copyBlockFrequency(CallSiteBlock, CallSuccessor->getParent());
+        if (!InlineInfo.CallSuccessorBlockDeleted) {
+          // The instruction following the call is part of a new basic block
+          // created during the inlining process. This does not have an entry in
+          // the BFI. We create an entry by copying the frequency of the
+          // original block containing the call.
+          copyBlockFrequency(CallSiteBlock, CallSuccessor->getParent());
+        }
 
         ++NumInlined;
 

Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=262679&r1=262678&r2=262679&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Thu Mar  3 18:44:01 2016
@@ -1994,8 +1994,11 @@ bool llvm::InlineFunction(CallSite CS, I
 
   // If we inlined any musttail calls and the original return is now
   // unreachable, delete it.  It can only contain a bitcast and ret.
-  if (InlinedMustTailCalls && pred_begin(AfterCallBB) == pred_end(AfterCallBB))
+  if (InlinedMustTailCalls &&
+      pred_begin(AfterCallBB) == pred_end(AfterCallBB)) {
+    IFI.CallSuccessorBlockDeleted = true;
     AfterCallBB->eraseFromParent();
+  }
 
   // We should always be able to fold the entry block of the function into the
   // single predecessor of the block...