Intrinsify String.length() and String.isEmpty() as HIR.
Use HArrayLength for String.length() in anticipation of
changing the String.charAt() to HBoundsCheck+HArrayGet to
allow the existing BCE to seamlessly work for strings.
Use HArrayLength+HEqual for String.isEmpty().
We previously relied on inlining but we now want to apply
the new intrinsics even when we do not inline, i.e. when
compiling debuggable (as is currently the case for boot
image) or when we hit inlining limits, i.e. depth, size,
or the number of accumulated dex registers.
Bug: 28330359
Change-Id: Iab9d2f6d2967bdd930a72eb461f27efe8f37c103
diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index d7b3856..fd79901 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -101,6 +101,7 @@
void SimplifyCompare(HInvoke* invoke, bool is_signum, Primitive::Type type);
void SimplifyIsNaN(HInvoke* invoke);
void SimplifyFP2Int(HInvoke* invoke);
+ void SimplifyStringIsEmptyOrLength(HInvoke* invoke);
void SimplifyMemBarrier(HInvoke* invoke, MemBarrierKind barrier_kind);
OptimizingCompilerStats* stats_;
@@ -1673,6 +1674,27 @@
invoke->ReplaceWithExceptInReplacementAtIndex(select, 0); // false at index 0
}
+void InstructionSimplifierVisitor::SimplifyStringIsEmptyOrLength(HInvoke* invoke) {
+ HInstruction* str = invoke->InputAt(0);
+ uint32_t dex_pc = invoke->GetDexPc();
+ // We treat String as an array to allow DCE and BCE to seamlessly work on strings,
+ // so create the HArrayLength.
+ HArrayLength* length = new (GetGraph()->GetArena()) HArrayLength(str, dex_pc);
+ length->MarkAsStringLength();
+ HInstruction* replacement;
+ if (invoke->GetIntrinsic() == Intrinsics::kStringIsEmpty) {
+ // For String.isEmpty(), create the `HEqual` representing the `length == 0`.
+ invoke->GetBlock()->InsertInstructionBefore(length, invoke);
+ HIntConstant* zero = GetGraph()->GetIntConstant(0);
+ HEqual* equal = new (GetGraph()->GetArena()) HEqual(length, zero, dex_pc);
+ replacement = equal;
+ } else {
+ DCHECK_EQ(invoke->GetIntrinsic(), Intrinsics::kStringLength);
+ replacement = length;
+ }
+ invoke->GetBlock()->ReplaceAndRemoveInstructionWith(invoke, replacement);
+}
+
void InstructionSimplifierVisitor::SimplifyMemBarrier(HInvoke* invoke, MemBarrierKind barrier_kind) {
uint32_t dex_pc = invoke->GetDexPc();
HMemoryBarrier* mem_barrier = new (GetGraph()->GetArena()) HMemoryBarrier(barrier_kind, dex_pc);
@@ -1719,6 +1741,10 @@
case Intrinsics::kDoubleDoubleToLongBits:
SimplifyFP2Int(instruction);
break;
+ case Intrinsics::kStringIsEmpty:
+ case Intrinsics::kStringLength:
+ SimplifyStringIsEmptyOrLength(instruction);
+ break;
case Intrinsics::kUnsafeLoadFence:
SimplifyMemBarrier(instruction, MemBarrierKind::kLoadAny);
break;