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/code_generator.cc b/compiler/optimizing/code_generator.cc
index e7fa4e4..51fbaea 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -50,6 +50,7 @@
#include "mirror/array-inl.h"
#include "mirror/object_array-inl.h"
#include "mirror/object_reference.h"
+#include "mirror/string.h"
#include "parallel_move_resolver.h"
#include "ssa_liveness_analysis.h"
#include "utils/assembler.h"
@@ -139,6 +140,12 @@
return pointer_size * index;
}
+uint32_t CodeGenerator::GetArrayLengthOffset(HArrayLength* array_length) {
+ return array_length->IsStringLength()
+ ? mirror::String::CountOffset().Uint32Value()
+ : mirror::Array::LengthOffset().Uint32Value();
+}
+
bool CodeGenerator::GoesToNextBlock(HBasicBlock* current, HBasicBlock* next) const {
DCHECK_EQ((*block_order_)[current_block_index_], current);
return GetNextBlockToEmit() == FirstNonEmptyBlock(next);
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index d69c410..6e75e3b 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -340,6 +340,11 @@
// Pointer variant for ArtMethod and ArtField arrays.
size_t GetCachePointerOffset(uint32_t index);
+ // Helper that returns the offset of the array's length field.
+ // Note: Besides the normal arrays, we also use the HArrayLength for
+ // accessing the String's `count` field in String intrinsics.
+ static uint32_t GetArrayLengthOffset(HArrayLength* array_length);
+
void EmitParallelMoves(Location from1,
Location to1,
Primitive::Type type1,
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 197e473..e010662 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -4742,7 +4742,7 @@
void InstructionCodeGeneratorARM::VisitArrayLength(HArrayLength* instruction) {
LocationSummary* locations = instruction->GetLocations();
- uint32_t offset = mirror::Array::LengthOffset().Uint32Value();
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
Register obj = locations->InAt(0).AsRegister<Register>();
Register out = locations->Out().AsRegister<Register>();
__ LoadFromOffset(kLoadWord, out, obj, offset);
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 9680f2b..261c04f 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -2118,9 +2118,9 @@
}
void InstructionCodeGeneratorARM64::VisitArrayLength(HArrayLength* instruction) {
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
BlockPoolsScope block_pools(GetVIXLAssembler());
- __ Ldr(OutputRegister(instruction),
- HeapOperand(InputRegisterAt(instruction, 0), mirror::Array::LengthOffset()));
+ __ Ldr(OutputRegister(instruction), HeapOperand(InputRegisterAt(instruction, 0), offset));
codegen_->MaybeRecordImplicitNullCheck(instruction);
}
diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index 12d1164..fb50680 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -1803,7 +1803,7 @@
void InstructionCodeGeneratorMIPS::VisitArrayLength(HArrayLength* instruction) {
LocationSummary* locations = instruction->GetLocations();
- uint32_t offset = mirror::Array::LengthOffset().Uint32Value();
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
Register obj = locations->InAt(0).AsRegister<Register>();
Register out = locations->Out().AsRegister<Register>();
__ LoadFromOffset(kLoadWord, out, obj, offset);
diff --git a/compiler/optimizing/code_generator_mips64.cc b/compiler/optimizing/code_generator_mips64.cc
index 56ac38e..e67d8d0 100644
--- a/compiler/optimizing/code_generator_mips64.cc
+++ b/compiler/optimizing/code_generator_mips64.cc
@@ -1426,7 +1426,7 @@
void InstructionCodeGeneratorMIPS64::VisitArrayLength(HArrayLength* instruction) {
LocationSummary* locations = instruction->GetLocations();
- uint32_t offset = mirror::Array::LengthOffset().Uint32Value();
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
GpuRegister obj = locations->InAt(0).AsRegister<GpuRegister>();
GpuRegister out = locations->Out().AsRegister<GpuRegister>();
__ LoadFromOffset(kLoadWord, out, obj, offset);
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 6dc480b..50892a9 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -5480,7 +5480,7 @@
void InstructionCodeGeneratorX86::VisitArrayLength(HArrayLength* instruction) {
LocationSummary* locations = instruction->GetLocations();
- uint32_t offset = mirror::Array::LengthOffset().Uint32Value();
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
Register obj = locations->InAt(0).AsRegister<Register>();
Register out = locations->Out().AsRegister<Register>();
__ movl(out, Address(obj, offset));
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 96ec09c..56c5b06 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -4956,7 +4956,7 @@
void InstructionCodeGeneratorX86_64::VisitArrayLength(HArrayLength* instruction) {
LocationSummary* locations = instruction->GetLocations();
- uint32_t offset = mirror::Array::LengthOffset().Uint32Value();
+ uint32_t offset = CodeGenerator::GetArrayLengthOffset(instruction);
CpuRegister obj = locations->InAt(0).AsRegister<CpuRegister>();
CpuRegister out = locations->Out().AsRegister<CpuRegister>();
__ movl(out, Address(obj, offset));
diff --git a/compiler/optimizing/graph_visualizer.cc b/compiler/optimizing/graph_visualizer.cc
index 9efc13f..568b8a8 100644
--- a/compiler/optimizing/graph_visualizer.cc
+++ b/compiler/optimizing/graph_visualizer.cc
@@ -389,6 +389,11 @@
<< instance_of->MustDoNullCheck() << std::noboolalpha;
}
+ void VisitArrayLength(HArrayLength* array_length) OVERRIDE {
+ StartAttributeStream("is_string_length") << std::boolalpha
+ << array_length->IsStringLength() << std::noboolalpha;
+ }
+
void VisitArraySet(HArraySet* array_set) OVERRIDE {
StartAttributeStream("value_can_be_null") << std::boolalpha
<< array_set->GetValueCanBeNull() << std::noboolalpha;
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;
diff --git a/compiler/optimizing/intrinsics.cc b/compiler/optimizing/intrinsics.cc
index 5d4c4e2..418d59c 100644
--- a/compiler/optimizing/intrinsics.cc
+++ b/compiler/optimizing/intrinsics.cc
@@ -388,10 +388,8 @@
case kIntrinsicGetCharsNoCheck:
return Intrinsics::kStringGetCharsNoCheck;
case kIntrinsicIsEmptyOrLength:
- // The inliner can handle these two cases - and this is the preferred approach
- // since after inlining the call is no longer visible (as opposed to waiting
- // until codegen to handle intrinsic).
- return Intrinsics::kNone;
+ return ((method.d.data & kIntrinsicFlagIsEmpty) == 0) ?
+ Intrinsics::kStringLength : Intrinsics::kStringIsEmpty;
case kIntrinsicIndexOf:
return ((method.d.data & kIntrinsicFlagBase0) == 0) ?
Intrinsics::kStringIndexOfAfter : Intrinsics::kStringIndexOf;
diff --git a/compiler/optimizing/intrinsics.h b/compiler/optimizing/intrinsics.h
index 39a1313..214250f 100644
--- a/compiler/optimizing/intrinsics.h
+++ b/compiler/optimizing/intrinsics.h
@@ -239,6 +239,8 @@
UNREACHABLE_INTRINSIC(Arch, LongCompare) \
UNREACHABLE_INTRINSIC(Arch, IntegerSignum) \
UNREACHABLE_INTRINSIC(Arch, LongSignum) \
+UNREACHABLE_INTRINSIC(Arch, StringIsEmpty) \
+UNREACHABLE_INTRINSIC(Arch, StringLength) \
UNREACHABLE_INTRINSIC(Arch, UnsafeLoadFence) \
UNREACHABLE_INTRINSIC(Arch, UnsafeStoreFence) \
UNREACHABLE_INTRINSIC(Arch, UnsafeFullFence)
diff --git a/compiler/optimizing/intrinsics_list.h b/compiler/optimizing/intrinsics_list.h
index dd9294d..db60238 100644
--- a/compiler/optimizing/intrinsics_list.h
+++ b/compiler/optimizing/intrinsics_list.h
@@ -107,6 +107,8 @@
V(StringGetCharsNoCheck, kDirect, kNeedsEnvironmentOrCache, kReadSideEffects, kCanThrow) \
V(StringIndexOf, kDirect, kNeedsEnvironmentOrCache, kReadSideEffects, kCanThrow) \
V(StringIndexOfAfter, kDirect, kNeedsEnvironmentOrCache, kReadSideEffects, kCanThrow) \
+ V(StringIsEmpty, kDirect, kNeedsEnvironmentOrCache, kReadSideEffects, kNoThrow) \
+ V(StringLength, kDirect, kNeedsEnvironmentOrCache, kReadSideEffects, kNoThrow) \
V(StringNewStringFromBytes, kStatic, kNeedsEnvironmentOrCache, kAllSideEffects, kCanThrow) \
V(StringNewStringFromChars, kStatic, kNeedsEnvironmentOrCache, kAllSideEffects, kCanThrow) \
V(StringNewStringFromString, kStatic, kNeedsEnvironmentOrCache, kAllSideEffects, kCanThrow) \
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index afb995d..88eba4c 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -5226,9 +5226,22 @@
return obj == InputAt(0);
}
+ void MarkAsStringLength() { SetPackedFlag<kFlagIsStringLength>(); }
+ bool IsStringLength() const { return GetPackedFlag<kFlagIsStringLength>(); }
+
DECLARE_INSTRUCTION(ArrayLength);
private:
+ // We treat a String as an array, creating the HArrayLength from String.length()
+ // or String.isEmpty() intrinsic in the instruction simplifier. We can always
+ // determine whether a particular HArrayLength is actually a String.length() by
+ // looking at the type of the input but that requires holding the mutator lock, so
+ // we prefer to use a flag, so that code generators don't need to do the locking.
+ static constexpr size_t kFlagIsStringLength = kNumberOfExpressionPackedBits;
+ static constexpr size_t kNumberOfArrayLengthPackedBits = kFlagIsStringLength + 1;
+ static_assert(kNumberOfArrayLengthPackedBits <= HInstruction::kMaxNumberOfPackedBits,
+ "Too many packed fields.");
+
DISALLOW_COPY_AND_ASSIGN(HArrayLength);
};
diff --git a/test/536-checker-intrinsic-optimization/src/Main.java b/test/536-checker-intrinsic-optimization/src/Main.java
index be666e9..15a9504 100644
--- a/test/536-checker-intrinsic-optimization/src/Main.java
+++ b/test/536-checker-intrinsic-optimization/src/Main.java
@@ -16,9 +16,69 @@
public class Main {
+ public static boolean doThrow = false;
+
+ public static void assertIntEquals(int expected, int result) {
+ if (expected != result) {
+ throw new Error("Expected: " + expected + ", found: " + result);
+ }
+ }
+
+ public static void assertBooleanEquals(boolean expected, boolean result) {
+ if (expected != result) {
+ throw new Error("Expected: " + expected + ", found: " + result);
+ }
+ }
+
public static void main(String[] args) {
stringEqualsSame();
stringArgumentNotNull("Foo");
+
+ assertIntEquals(0, $opt$noinline$getStringLength(""));
+ assertIntEquals(3, $opt$noinline$getStringLength("abc"));
+ assertIntEquals(10, $opt$noinline$getStringLength("0123456789"));
+
+ assertBooleanEquals(true, $opt$noinline$isStringEmpty(""));
+ assertBooleanEquals(false, $opt$noinline$isStringEmpty("abc"));
+ assertBooleanEquals(false, $opt$noinline$isStringEmpty("0123456789"));
+ }
+
+ /// CHECK-START: int Main.$opt$noinline$getStringLength(java.lang.String) instruction_simplifier (before)
+ /// CHECK-DAG: <<Length:i\d+>> InvokeVirtual intrinsic:StringLength
+ /// CHECK-DAG: Return [<<Length>>]
+
+ /// CHECK-START: int Main.$opt$noinline$getStringLength(java.lang.String) instruction_simplifier (after)
+ /// CHECK-DAG: <<String:l\d+>> ParameterValue
+ /// CHECK-DAG: <<NullCk:l\d+>> NullCheck [<<String>>]
+ /// CHECK-DAG: <<Length:i\d+>> ArrayLength [<<NullCk>>] is_string_length:true
+ /// CHECK-DAG: Return [<<Length>>]
+
+ /// CHECK-START: int Main.$opt$noinline$getStringLength(java.lang.String) instruction_simplifier (after)
+ /// CHECK-NOT: InvokeVirtual intrinsic:StringLength
+
+ static public int $opt$noinline$getStringLength(String s) {
+ if (doThrow) { throw new Error(); }
+ return s.length();
+ }
+
+ /// CHECK-START: boolean Main.$opt$noinline$isStringEmpty(java.lang.String) instruction_simplifier (before)
+ /// CHECK-DAG: <<IsEmpty:z\d+>> InvokeVirtual intrinsic:StringIsEmpty
+ /// CHECK-DAG: Return [<<IsEmpty>>]
+
+ /// CHECK-START: boolean Main.$opt$noinline$isStringEmpty(java.lang.String) instruction_simplifier (after)
+ /// CHECK-DAG: <<String:l\d+>> ParameterValue
+ /// CHECK-DAG: <<Const0:i\d+>> IntConstant 0
+ /// CHECK-DAG: <<NullCk:l\d+>> NullCheck [<<String>>]
+ /// CHECK-DAG: <<Length:i\d+>> ArrayLength [<<NullCk>>] is_string_length:true
+ /// CHECK-DAG: <<IsEmpty:z\d+>> Equal [<<Length>>,<<Const0>>]
+ /// CHECK-DAG: Return [<<IsEmpty>>]
+
+ /// CHECK-START: boolean Main.$opt$noinline$isStringEmpty(java.lang.String) instruction_simplifier (after)
+ /// CHECK-NOT: InvokeVirtual intrinsic:StringIsEmpty
+
+ static public boolean $opt$noinline$isStringEmpty(String s) {
+ if (doThrow) { throw new Error(); }
+ return s.isEmpty();
}
/// CHECK-START: boolean Main.stringEqualsSame() instruction_simplifier (before)