[PATCH] D105805: [NFC] Do not track calls to inlined intrinsics in IFI.

[Jeroen Dobbelaere via Phabricator via llvm-commits]

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Just like intrinsics are not tracked for IFI.InlinedCalls, they should not be tracked for IFI.InlinedCallSites.

In the current top-of-tree this change is a NFC, but the full restrict patches (D68484 <https://reviews.llvm.org/D68484>) potentially trigger an read-after-free
if intrinsics are also added to the InlindeCallSites, due to a late optimization potentially removing some of the inlined intrinsics.

Also see https://lists.llvm.org/pipermail/llvm-dev/2021-July/151722.html for a discussion about the problem.


https://reviews.llvm.org/D105805

Files:
  llvm/lib/Transforms/IPO/Inliner.cpp
  llvm/lib/Transforms/Utils/InlineFunction.cpp


Index: llvm/lib/Transforms/Utils/InlineFunction.cpp
===================================================================
--- llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -2438,14 +2438,17 @@
   // before we splice the inlined code into the CFG and lose track of which
   // blocks were actually inlined, collect the call sites. We only do this if
   // call graph updates weren't requested, as those provide value handle based
-  // tracking of inlined call sites instead.
+  // tracking of inlined call sites instead. Calls to intrinsics are not
+  // collected because we expect them to become inline code.
   if (InlinedFunctionInfo.ContainsCalls && !IFI.CG) {
     // Otherwise just collect the raw call sites that were inlined.
     for (BasicBlock &NewBB :
          make_range(FirstNewBlock->getIterator(), Caller->end()))
       for (Instruction &I : NewBB)
         if (auto *CB = dyn_cast<CallBase>(&I))
-          IFI.InlinedCallSites.push_back(CB);
+          if (!(CB->getCalledFunction() &&
+                CB->getCalledFunction()->isIntrinsic()))
+            IFI.InlinedCallSites.push_back(CB);
   }
 
   // If we cloned in _exactly one_ basic block, and if that block ends in a
Index: llvm/lib/Transforms/IPO/Inliner.cpp
===================================================================
--- llvm/lib/Transforms/IPO/Inliner.cpp
+++ llvm/lib/Transforms/IPO/Inliner.cpp
@@ -1007,6 +1007,8 @@
 
         for (CallBase *ICB : reverse(IFI.InlinedCallSites)) {
           Function *NewCallee = ICB->getCalledFunction();
+          assert(!(NewCallee && NewCallee->isIntrinsic()) &&
+                 "Intrinsic calls should not be tracked.");
           if (!NewCallee) {
             // Try to promote an indirect (virtual) call without waiting for
             // the post-inline cleanup and the next DevirtSCCRepeatedPass


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