optimizing: do not illegally remove constructor barriers after inlining
Remove the illegal optimization that destroyed constructor barriers
after inlining invoke-super constructor calls.
---
According to JLS 7.5.1,
"Note that if one constructor invokes another constructor, and the
invoked constructor sets a final field, the freeze for the final field
takes place at the end of the invoked constructor."
This means if an object is published (stored to a location potentially
visible to another thread) inside of an outer constructor, all final
field stores from any inner constructors must be visible to other
threads.
Test: art/test.py
Bug: 37001605
Change-Id: I3b55f6c628ff1773dab88022a6475d50a1a6f906
diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 88f67fa..978c6a2 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -589,6 +589,11 @@
}
static bool RequiresConstructorBarrier(const DexCompilationUnit* cu, CompilerDriver* driver) {
+ // Can be null in unit tests only.
+ if (UNLIKELY(cu == nullptr)) {
+ return false;
+ }
+
Thread* self = Thread::Current();
return cu->IsConstructor()
&& driver->RequiresConstructorBarrier(self, cu->GetDexFile(), cu->GetClassDefIndex());
@@ -634,12 +639,9 @@
Primitive::Type type,
uint32_t dex_pc) {
if (type == Primitive::kPrimVoid) {
- if (graph_->ShouldGenerateConstructorBarrier()) {
- // The compilation unit is null during testing.
- if (dex_compilation_unit_ != nullptr) {
- DCHECK(RequiresConstructorBarrier(dex_compilation_unit_, compiler_driver_))
- << "Inconsistent use of ShouldGenerateConstructorBarrier. Should not generate a barrier.";
- }
+ // This may insert additional redundant constructor fences from the super constructors.
+ // TODO: remove redundant constructor fences (b/36656456).
+ if (RequiresConstructorBarrier(dex_compilation_unit_, compiler_driver_)) {
AppendInstruction(new (arena_) HMemoryBarrier(kStoreStore, dex_pc));
}
AppendInstruction(new (arena_) HReturnVoid(dex_pc));