[PATCH] D59112: [Bitcode] Fix bitcode compatibility issue with clang.arc.use intrinsic

[Steven Wu via Phabricator via llvm-commits]

steven_wu created this revision.
steven_wu added reviewers: pete, ahatanak, erik.pilkington, dexonsmith.
Herald added subscribers: jdoerfert, jkorous.
Herald added a project: LLVM.

In r349534, objc arc implementation is switched to use intrinsics and at
the same time, clang.arc.use is renamed to llvm.objc.clang.arc.use to
make the naming more consistent. The side-effect of that is llvm no
longer recognize it as intrinsics and codegen external references to
it instead.

Rather than upgrade the old intrinsics name to the new one and wait for
the arc-contract pass to remove it, simply remove it in the bitcode
upgrader.

rdar://problem/48607063


Repository:
  rL LLVM

https://reviews.llvm.org/D59112

Files:
  lib/IR/AutoUpgrade.cpp
  test/Bitcode/upgrade-clang-arc-use.ll
  test/Bitcode/upgrade-clang-arc-use.ll.bc


Index: test/Bitcode/upgrade-clang-arc-use.ll
===================================================================
--- /dev/null
+++ test/Bitcode/upgrade-clang-arc-use.ll
@@ -0,0 +1,13 @@
+; Test upgrade of clang.arc.use by removing it.
+
+; RUN: llvm-dis %s.bc -o - | FileCheck %s
+
+%0 = type opaque
+define void @foo() {
+  %1 = tail call %0* @foo0()
+; CHECK-NOT: clang.arc.use
+  call void (...) @clang.arc.use(%0* %1)
+  ret void
+}
+declare %0* @foo0()
+declare void @clang.arc.use(...)
Index: lib/IR/AutoUpgrade.cpp
===================================================================
--- lib/IR/AutoUpgrade.cpp
+++ lib/IR/AutoUpgrade.cpp
@@ -778,9 +778,20 @@
   return false;
 }
 
+static bool UpgradeIntrinsicFunction2(Function *F, Function *&NewFn) {
+  // Upgrade intrinsics that have the old name not beginning with "llvm.".
+  if (F->getName() == "clang.arc.use") {
+    NewFn = nullptr;
+    return true;
+  }
+
+  return false;
+}
+
 bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
   NewFn = nullptr;
-  bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn);
+  bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn) ||
+                  UpgradeIntrinsicFunction2(F, NewFn);
   assert(F != NewFn && "Intrinsic function upgraded to the same function");
 
   // Upgrade intrinsic attributes.  This does not change the function.
@@ -1571,6 +1582,12 @@
     // Get the Function's name.
     StringRef Name = F->getName();
 
+    // Handle clang.arc.use.
+    if (Name == "clang.arc.use") {
+      CI->eraseFromParent();
+      return;
+    }
+
     assert(Name.startswith("llvm.") && "Intrinsic doesn't start with 'llvm.'");
     Name = Name.substr(5);
 


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