Compensate in compiler for verifier shortcomings.
The verifier does not differentiate zero and null, so a move-object
of zero can be used as a non-object later on.
Change the compiler to ignore the object conversion when the input
is zero or a phi (which might just hold zeros). The type propagation
will then do proper inferencing of the types.
Also remove some stalled comments in ssa_builder.cc.
bug:31313170
test: dex2oat b31313170.apk
test: run-test 800
test: m test-art-host-run-test
Change-Id: I579d667415a7decf8ff2c2238dae4c13eec5d0e0
diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 5a6a212..f7dc237 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -1815,7 +1815,20 @@
case Instruction::MOVE_OBJECT:
case Instruction::MOVE_OBJECT_16:
case Instruction::MOVE_OBJECT_FROM16: {
- HInstruction* value = LoadLocal(instruction.VRegB(), Primitive::kPrimNot);
+ // The verifier has no notion of a null type, so a move-object of constant 0
+ // will lead to the same constant 0 in the destination register. To mimic
+ // this behavior, we just pretend we haven't seen a type change (int to reference)
+ // for the 0 constant and phis. We rely on our type propagation to eventually get the
+ // types correct.
+ uint32_t reg_number = instruction.VRegB();
+ HInstruction* value = (*current_locals_)[reg_number];
+ if (value->IsIntConstant()) {
+ DCHECK_EQ(value->AsIntConstant()->GetValue(), 0);
+ } else if (value->IsPhi()) {
+ DCHECK(value->GetType() == Primitive::kPrimInt || value->GetType() == Primitive::kPrimNot);
+ } else {
+ value = LoadLocal(reg_number, Primitive::kPrimNot);
+ }
UpdateLocal(instruction.VRegA(), value);
break;
}