Add fast Smi op version of switchable instance calls.

runtime/vm/stub_code_arm64.cc

Index: runtime/vm/stub_code_arm64.cc
diff --git a/runtime/vm/stub_code_arm64.cc b/runtime/vm/stub_code_arm64.cc
index 8c197ae9633a60e4a181dce76346ca96927bc3c6..e817f969af4ef071908bd565dab1b21e391970e4 100644
--- a/runtime/vm/stub_code_arm64.cc
+++ b/runtime/vm/stub_code_arm64.cc
@@ -2098,8 +2098,15 @@ void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
 }
 
 
+// Called from megamorphic calls.
+//  R1: receiver
+//  R5: MegamorphicCache (preserved)
+// Result:
+//  R1: target entry point
+//  CODE_REG: target Code
+//  R4: arguments descriptor
 void StubCode::EmitMegamorphicLookup(Assembler* assembler) {
-  __ LoadTaggedClassIdMayBeSmi(R0, R0);
+  __ LoadTaggedClassIdMayBeSmi(R0, R1);
   // R0: class ID of the receiver (smi).
   __ ldr(R4, FieldAddress(R5, MegamorphicCache::arguments_descriptor_offset()));
   __ ldr(R2, FieldAddress(R5, MegamorphicCache::buckets_offset()));
@@ -2139,13 +2146,6 @@ void StubCode::EmitMegamorphicLookup(Assembler* assembler) {
 }
 
 
-// Called from megamorphic calls.
-//  R0: receiver
-//  R5: MegamorphicCache (preserved)
-// Result:
-//  R1: target entry point
-//  CODE_REG: target Code
-//  R4: arguments descriptor
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler);
   __ ret();
@@ -2153,34 +2153,75 @@ void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
 
 
 // Called from switchable IC calls.
-//  R0: receiver
+//  R1: receiver
 //  R5: ICData (preserved)
 // Result:
 //  R1: target entry point
 //  CODE_REG: target Code object
 //  R4: arguments descriptor
-void StubCode::GenerateICLookupStub(Assembler* assembler) {
+static void EmitICLookup(Assembler* assembler,
+                         intptr_t args_checked,
+                         Token::Kind kind) {
+  if (kind != Token::kILLEGAL) {
+    __ Comment("Fast Smi op");
+    Label not_smi_or_overflow;
+
+    // R1: Receiver.
+    __ ldr(R2, Address(SP, + 0 * kWordSize));
+    // R2: Argument.
+    __ orr(TMP, R1, Operand(R2));
+    __ tsti(TMP, Immediate(kSmiTagMask));
+    __ b(&not_smi_or_overflow, NE);
+    switch (kind) {
+      case Token::kADD: {
+        __ adds(R0, R1, Operand(R2));  // Adds.
+        __ b(&not_smi_or_overflow, VS);  // Branch if overflow.
+        break;
+      }
+      case Token::kSUB: {
+        __ subs(R0, R1, Operand(R2));  // Subtract.
+        __ b(&not_smi_or_overflow, VS);  // Branch if overflow.
+        break;
+      }
+      case Token::kEQ: {
+        __ CompareRegisters(R1, R2);
+        __ LoadObject(R0, Bool::True());
+        __ LoadObject(R1, Bool::False());
+        __ csel(R0, R1, R0, NE);
+        break;
+      }
+      default: UNIMPLEMENTED();
+    }
+    // Return past the call to lookup result.
+    __ add(LR, LR, Operand(Instr::kInstrSize));
+    __ ret();
+
+    __ Bind(&not_smi_or_overflow);
+  }
+
   Label loop, found, miss;
   __ ldr(R4, FieldAddress(R5, ICData::arguments_descriptor_offset()));
   __ ldr(R8, FieldAddress(R5, ICData::ic_data_offset()));
   __ AddImmediate(R8, R8, Array::data_offset() - kHeapObjectTag);
   // R8: first IC entry
-  __ LoadTaggedClassIdMayBeSmi(R1, R0);
+  __ LoadTaggedClassIdMayBeSmi(R0, R1);
   // R1: receiver cid as Smi
 
   __ Bind(&loop);
   __ ldr(R2, Address(R8, 0));
-  __ cmp(R1, Operand(R2));
+  __ cmp(R0, Operand(R2));
   __ b(&found, EQ);
   __ CompareImmediate(R2, Smi::RawValue(kIllegalCid));
   __ b(&miss, EQ);
 
-  const intptr_t entry_length = ICData::TestEntryLengthFor(1) * kWordSize;
+  const intptr_t entry_length =
+      ICData::TestEntryLengthFor(args_checked) * kWordSize;
   __ AddImmediate(R8, R8, entry_length);  // Next entry.
   __ b(&loop);
 
   __ Bind(&found);
-  const intptr_t target_offset = ICData::TargetIndexFor(1) * kWordSize;
+  const intptr_t target_offset =
+      ICData::TargetIndexFor(args_checked) * kWordSize;
   __ ldr(R0, Address(R8, target_offset));
   __ ldr(R1, FieldAddress(R0, Function::entry_point_offset()));
   __ ldr(CODE_REG, FieldAddress(R0, Function::code_offset()));
@@ -2193,6 +2234,26 @@ void StubCode::GenerateICLookupStub(Assembler* assembler) {
   __ ret();
 }
 
+
+void StubCode::GenerateICLookupStub(Assembler* assembler) {
+  EmitICLookup(assembler, 1, Token::kILLEGAL);
+}
+
+
+void StubCode::GenerateICSmiAddLookupStub(Assembler* assembler) {
+  EmitICLookup(assembler, 2, Token::kADD);
+}
+
+
+void StubCode::GenerateICSmiSubLookupStub(Assembler* assembler) {
+  EmitICLookup(assembler, 2, Token::kSUB);
+}
+
+
+void StubCode::GenerateICSmiEqualLookupStub(Assembler* assembler) {
+  EmitICLookup(assembler, 2, Token::kEQ);
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64