diff options
| -rw-r--r-- | compiler/optimizing/intrinsics_arm64.cc | 97 |
1 files changed, 96 insertions, 1 deletions
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc index 56313730dc..a5332ea794 100644 --- a/compiler/optimizing/intrinsics_arm64.cc +++ b/compiler/optimizing/intrinsics_arm64.cc @@ -1055,6 +1055,102 @@ void IntrinsicCodeGeneratorARM64::VisitStringCompareTo(HInvoke* invoke) { __ Bind(slow_path->GetExitLabel()); } +void IntrinsicLocationsBuilderARM64::VisitStringEquals(HInvoke* invoke) { + LocationSummary* locations = new (arena_) LocationSummary(invoke, + LocationSummary::kNoCall, + kIntrinsified); + locations->SetInAt(0, Location::RequiresRegister()); + locations->SetInAt(1, Location::RequiresRegister()); + // Temporary registers to store lengths of strings and for calculations. + locations->AddTemp(Location::RequiresRegister()); + locations->AddTemp(Location::RequiresRegister()); + + locations->SetOut(Location::RequiresRegister(), Location::kOutputOverlap); +} + +void IntrinsicCodeGeneratorARM64::VisitStringEquals(HInvoke* invoke) { + vixl::MacroAssembler* masm = GetVIXLAssembler(); + LocationSummary* locations = invoke->GetLocations(); + + Register str = WRegisterFrom(locations->InAt(0)); + Register arg = WRegisterFrom(locations->InAt(1)); + Register out = XRegisterFrom(locations->Out()); + + UseScratchRegisterScope scratch_scope(masm); + Register temp = scratch_scope.AcquireW(); + Register temp1 = WRegisterFrom(locations->GetTemp(0)); + Register temp2 = WRegisterFrom(locations->GetTemp(1)); + + vixl::Label loop; + vixl::Label end; + vixl::Label return_true; + vixl::Label return_false; + + // Get offsets of count, value, and class fields within a string object. + const int32_t count_offset = mirror::String::CountOffset().Int32Value(); + const int32_t value_offset = mirror::String::ValueOffset().Int32Value(); + const int32_t class_offset = mirror::Object::ClassOffset().Int32Value(); + + // Note that the null check must have been done earlier. + DCHECK(!invoke->CanDoImplicitNullCheckOn(invoke->InputAt(0))); + + // Check if input is null, return false if it is. + __ Cbz(arg, &return_false); + + // Reference equality check, return true if same reference. + __ Cmp(str, arg); + __ B(&return_true, eq); + + // Instanceof check for the argument by comparing class fields. + // All string objects must have the same type since String cannot be subclassed. + // Receiver must be a string object, so its class field is equal to all strings' class fields. + // If the argument is a string object, its class field must be equal to receiver's class field. + __ Ldr(temp, MemOperand(str.X(), class_offset)); + __ Ldr(temp1, MemOperand(arg.X(), class_offset)); + __ Cmp(temp, temp1); + __ B(&return_false, ne); + + // Load lengths of this and argument strings. + __ Ldr(temp, MemOperand(str.X(), count_offset)); + __ Ldr(temp1, MemOperand(arg.X(), count_offset)); + // Check if lengths are equal, return false if they're not. + __ Cmp(temp, temp1); + __ B(&return_false, ne); + // Store offset of string value in preparation for comparison loop + __ Mov(temp1, value_offset); + // Return true if both strings are empty. + __ Cbz(temp, &return_true); + + // Assertions that must hold in order to compare strings 4 characters at a time. + DCHECK_ALIGNED(value_offset, 8); + static_assert(IsAligned<8>(kObjectAlignment), "String of odd length is not zero padded"); + + temp1 = temp1.X(); + temp2 = temp2.X(); + + // Loop to compare strings 4 characters at a time starting at the beginning of the string. + // Ok to do this because strings are zero-padded to be 8-byte aligned. + __ Bind(&loop); + __ Ldr(out, MemOperand(str.X(), temp1)); + __ Ldr(temp2, MemOperand(arg.X(), temp1)); + __ Add(temp1, temp1, Operand(sizeof(uint64_t))); + __ Cmp(out, temp2); + __ B(&return_false, ne); + __ Sub(temp, temp, Operand(4), SetFlags); + __ B(&loop, gt); + + // Return true and exit the function. + // If loop does not result in returning false, we return true. + __ Bind(&return_true); + __ Mov(out, 1); + __ B(&end); + + // Return false and exit the function. + __ Bind(&return_false); + __ Mov(out, 0); + __ Bind(&end); +} + static void GenerateVisitStringIndexOf(HInvoke* invoke, vixl::MacroAssembler* masm, CodeGeneratorARM64* codegen, @@ -1229,7 +1325,6 @@ void IntrinsicCodeGeneratorARM64::Visit ## Name(HInvoke* invoke ATTRIBUTE_UNUSED UNIMPLEMENTED_INTRINSIC(SystemArrayCopyChar) UNIMPLEMENTED_INTRINSIC(ReferenceGetReferent) UNIMPLEMENTED_INTRINSIC(StringGetCharsNoCheck) -UNIMPLEMENTED_INTRINSIC(StringEquals) #undef UNIMPLEMENTED_INTRINSIC |