Merge pull request #23939 from gottesmm/swift-5.1-branch-rdar49794321

[5.1][ownership] Fix a corner case in the linear lifetime checker.

Author: gottesmm

lib/SIL/LinearLifetimeChecker.cpp

@@ -486,6 +486,25 @@ LinearLifetimeError swift::valueHasLinearLifetime(
   // have been detected by initializing our consuming uses. So we are done.
   if (consumingUses.size() == 1 &&
       consumingUses[0].getParent() == value->getParentBlock()) {
+    // Check if any of our non consuming uses are not in the parent block. We
+    // flag those as additional use after frees. Any in the same block, we would
+    // have flagged.
+    if (llvm::any_of(nonConsumingUses, [&](BranchPropagatedUser user) {
+          return user.getParent() != value->getParentBlock();
+        })) {
+      state.error.handleUseAfterFree([&] {
+        llvm::errs() << "Function: '" << value->getFunction()->getName()
+                     << "'\n"
+                     << "Found use after free due to unvisited non lifetime "
+                        "ending uses?!\n"
+                     << "Value: " << *value << "    Remaining Users:\n";
+        for (const auto &user : nonConsumingUses) {
+          llvm::errs() << "User: " << *user.getInst();
+        }
+        llvm::errs() << "\n";
+      });
+    }
+
     return state.error;
   }
 

test/SIL/ownership-verifier/over_consume.sil

@@ -22,6 +22,13 @@ case some(T)
 case none
 }
 
+protocol Error {}
+
+struct NativeObjectPair {
+  var obj1 : Builtin.NativeObject
+  var obj2 : Builtin.NativeObject
+}
+
 class SuperKlass {
   func doSomething()
 }
@@ -485,3 +492,35 @@ bb0(%0 : @guaranteed $ClassProtConformingRef, %1 : @owned $ClassProtConformingRe
   %5 = tuple(%3 : $ClassProt, %4 : $ClassProt)
   return %5 : $(ClassProt, ClassProt)
 }
+
+sil [ossa] @eliminate_copy_try_apple_callee : $@convention(thin) (@owned Builtin.NativeObject) -> @error Error {
+entry(%0 : @owned $Builtin.NativeObject):
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+
+// CHECK-LABEL: Function: 'use_after_free_consume_in_same_block'
+// CHECK: Found use after free due to unvisited non lifetime ending uses?!
+// CHECK: Value:   %3 = copy_value %2 : $Builtin.NativeObject
+// CHECK:     Remaining Users:
+// CHECK: User:   %10 = apply %7(%3) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+sil [ossa] @use_after_free_consume_in_same_block : $@convention(thin) (@owned NativeObjectPair) -> @error Error {
+bb0(%0 : @owned $NativeObjectPair):
+  %1 = begin_borrow %0 : $NativeObjectPair
+  %2 = struct_extract %1 : $NativeObjectPair, #NativeObjectPair.obj1
+  %3 = copy_value %2 : $Builtin.NativeObject
+  end_borrow %1 : $NativeObjectPair
+  destroy_value %0 : $NativeObjectPair
+  %4 = function_ref @eliminate_copy_try_apple_callee : $@convention(thin) (@owned Builtin.NativeObject) -> @error Error
+  %5 = function_ref @guaranteed_user : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  try_apply %4(%3) : $@convention(thin) (@owned Builtin.NativeObject) -> @error Error, normal bb1, error bb2
+
+bb1(%errorEmptyTup: $()):
+  apply %5(%3) : $@convention(thin) (@guaranteed Builtin.NativeObject) -> ()
+  %9999 = tuple()
+  return %9999 : $()
+
+bb2(%error : @owned $Error):
+  throw %error : $Error
+}