MIPS32: java.lang.String.equals
Add intrinsic support for String.equals on MIPS32.
Change-Id: I2d184aa4d5dae7cdd4a89c2c902535692c9e7393
diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index 8106499..959adb4 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -40,12 +40,8 @@
static constexpr Register kMethodRegisterArgument = A0;
// We need extra temporary/scratch registers (in addition to AT) in some cases.
-static constexpr Register TMP = T8;
static constexpr FRegister FTMP = F8;
-// ART Thread Register.
-static constexpr Register TR = S1;
-
Location MipsReturnLocation(Primitive::Type return_type) {
switch (return_type) {
case Primitive::kPrimBoolean:
diff --git a/compiler/optimizing/intrinsics.cc b/compiler/optimizing/intrinsics.cc
index dbe7524..b01324e 100644
--- a/compiler/optimizing/intrinsics.cc
+++ b/compiler/optimizing/intrinsics.cc
@@ -89,10 +89,7 @@
}
}
-static Intrinsics GetIntrinsic(InlineMethod method, InstructionSet instruction_set) {
- if (instruction_set == kMips) {
- return Intrinsics::kNone;
- }
+static Intrinsics GetIntrinsic(InlineMethod method) {
switch (method.opcode) {
// Floating-point conversions.
case kIntrinsicDoubleCvt:
@@ -431,7 +428,7 @@
DexFileMethodInliner* inliner = driver_->GetMethodInlinerMap()->GetMethodInliner(&dex_file);
DCHECK(inliner != nullptr);
if (inliner->IsIntrinsic(invoke->GetDexMethodIndex(), &method)) {
- Intrinsics intrinsic = GetIntrinsic(method, graph_->GetInstructionSet());
+ Intrinsics intrinsic = GetIntrinsic(method);
if (intrinsic != Intrinsics::kNone) {
if (!CheckInvokeType(intrinsic, invoke, dex_file)) {
diff --git a/compiler/optimizing/intrinsics_mips.cc b/compiler/optimizing/intrinsics_mips.cc
index 5efcf4e..a94e3a8 100644
--- a/compiler/optimizing/intrinsics_mips.cc
+++ b/compiler/optimizing/intrinsics_mips.cc
@@ -138,6 +138,108 @@
#define __ assembler->
+// boolean java.lang.String.equals(Object anObject)
+void IntrinsicLocationsBuilderMIPS::VisitStringEquals(HInvoke* invoke) {
+ LocationSummary* locations = new (arena_) LocationSummary(invoke,
+ LocationSummary::kNoCall,
+ kIntrinsified);
+ locations->SetInAt(0, Location::RequiresRegister());
+ locations->SetInAt(1, Location::RequiresRegister());
+ locations->SetOut(Location::RequiresRegister());
+
+ // Temporary registers to store lengths of strings and for calculations.
+ locations->AddTemp(Location::RequiresRegister());
+ locations->AddTemp(Location::RequiresRegister());
+ locations->AddTemp(Location::RequiresRegister());
+}
+
+void IntrinsicCodeGeneratorMIPS::VisitStringEquals(HInvoke* invoke) {
+ MipsAssembler* assembler = GetAssembler();
+ LocationSummary* locations = invoke->GetLocations();
+
+ Register str = locations->InAt(0).AsRegister<Register>();
+ Register arg = locations->InAt(1).AsRegister<Register>();
+ Register out = locations->Out().AsRegister<Register>();
+
+ Register temp1 = locations->GetTemp(0).AsRegister<Register>();
+ Register temp2 = locations->GetTemp(1).AsRegister<Register>();
+ Register temp3 = locations->GetTemp(2).AsRegister<Register>();
+
+ MipsLabel loop;
+ MipsLabel end;
+ MipsLabel return_true;
+ MipsLabel return_false;
+
+ // Get offsets of count, value, and class fields within a string object.
+ const uint32_t count_offset = mirror::String::CountOffset().Uint32Value();
+ const uint32_t value_offset = mirror::String::ValueOffset().Uint32Value();
+ const uint32_t class_offset = mirror::Object::ClassOffset().Uint32Value();
+
+ // Note that the null check must have been done earlier.
+ DCHECK(!invoke->CanDoImplicitNullCheckOn(invoke->InputAt(0)));
+
+ // If the register containing the pointer to "this", and the register
+ // containing the pointer to "anObject" are the same register then
+ // "this", and "anObject" are the same object and we can
+ // short-circuit the logic to a true result.
+ if (str == arg) {
+ __ LoadConst32(out, 1);
+ return;
+ }
+
+ // Check if input is null, return false if it is.
+ __ Beqz(arg, &return_false);
+
+ // Reference equality check, return true if same reference.
+ __ Beq(str, arg, &return_true);
+
+ // 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.
+ __ Lw(temp1, str, class_offset);
+ __ Lw(temp2, arg, class_offset);
+ __ Bne(temp1, temp2, &return_false);
+
+ // Load lengths of this and argument strings.
+ __ Lw(temp1, str, count_offset);
+ __ Lw(temp2, arg, count_offset);
+ // Check if lengths are equal, return false if they're not.
+ __ Bne(temp1, temp2, &return_false);
+ // Return true if both strings are empty.
+ __ Beqz(temp1, &return_true);
+
+ // Don't overwrite input registers
+ __ Move(TMP, str);
+ __ Move(temp3, arg);
+
+ // Assertions that must hold in order to compare strings 2 characters at a time.
+ DCHECK_ALIGNED(value_offset, 4);
+ static_assert(IsAligned<4>(kObjectAlignment), "String of odd length is not zero padded");
+
+ // Loop to compare strings 2 characters at a time starting at the beginning of the string.
+ // Ok to do this because strings are zero-padded.
+ __ Bind(&loop);
+ __ Lw(out, TMP, value_offset);
+ __ Lw(temp2, temp3, value_offset);
+ __ Bne(out, temp2, &return_false);
+ __ Addiu(TMP, TMP, 4);
+ __ Addiu(temp3, temp3, 4);
+ __ Addiu(temp1, temp1, -2);
+ __ Bgtz(temp1, &loop);
+
+ // Return true and exit the function.
+ // If loop does not result in returning false, we return true.
+ __ Bind(&return_true);
+ __ LoadConst32(out, 1);
+ __ B(&end);
+
+ // Return false and exit the function.
+ __ Bind(&return_false);
+ __ LoadConst32(out, 0);
+ __ Bind(&end);
+}
+
// Unimplemented intrinsics.
#define UNIMPLEMENTED_INTRINSIC(Name) \
@@ -204,7 +306,6 @@
UNIMPLEMENTED_INTRINSIC(UnsafeCASObject)
UNIMPLEMENTED_INTRINSIC(StringCharAt)
UNIMPLEMENTED_INTRINSIC(StringCompareTo)
-UNIMPLEMENTED_INTRINSIC(StringEquals)
UNIMPLEMENTED_INTRINSIC(StringIndexOf)
UNIMPLEMENTED_INTRINSIC(StringIndexOfAfter)
UNIMPLEMENTED_INTRINSIC(StringNewStringFromBytes)
diff --git a/runtime/arch/mips/registers_mips.h b/runtime/arch/mips/registers_mips.h
index 0f784ed..1096af0 100644
--- a/runtime/arch/mips/registers_mips.h
+++ b/runtime/arch/mips/registers_mips.h
@@ -59,6 +59,8 @@
SP = 29, // Stack pointer.
FP = 30, // Saved value/frame pointer.
RA = 31, // Return address.
+ TR = S1, // ART Thread Register
+ TMP = T8, // scratch register (in addition to AT)
kNumberOfCoreRegisters = 32,
kNoRegister = -1 // Signals an illegal register.
};
