Add fast Smi op version of switchable instance calls.

runtime/vm/stub_code_x64.cc

Index: runtime/vm/stub_code_x64.cc
diff --git a/runtime/vm/stub_code_x64.cc b/runtime/vm/stub_code_x64.cc
index 39d8dc96b0b2c7e2d040fa48f1b89270e7cceed6..e562e559ff6040d25961f11e23613c3631f46d2b 100644
--- a/runtime/vm/stub_code_x64.cc
+++ b/runtime/vm/stub_code_x64.cc
@@ -2088,6 +2088,13 @@ void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
 }
 
 
+// Called from megamorphic calls.
+//  RDI: receiver
+//  RBX: MegamorphicCache (preserved)
+// Result:
+//  RCX: target entry point
+//  CODE_REG: target Code
+//  R10: arguments descriptor
 void StubCode::EmitMegamorphicLookup(Assembler* assembler) {
   __ LoadTaggedClassIdMayBeSmi(RAX, RDI);
   // RAX: class ID of the receiver (smi).
@@ -2127,13 +2134,6 @@ void StubCode::EmitMegamorphicLookup(Assembler* assembler) {
 }
 
 
-// Called from megamorphic calls.
-//  RDI: receiver
-//  RBX: MegamorphicCache (preserved)
-// Result:
-//  RCX: target entry point
-//  CODE_REG: target Code
-//  R10: arguments descriptor
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler);
   __ ret();
@@ -2147,7 +2147,53 @@ void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
 //  RCX: target entry point
 //  CODE_REG: target Code object
 //  R10: 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;
+
+    // RDI: Receiver
+    __ movq(RCX, Address(RSP, + 1 * kWordSize));
+    // RCX: Argument
+    __ movq(R13, RCX);
+    __ orq(R13, RDI);
+    __ testq(R13, Immediate(kSmiTagMask));
+    __ j(NOT_ZERO, &not_smi_or_overflow);
+    __ movq(RAX, RDI);
+    switch (kind) {
+      case Token::kADD: {
+        __ addq(RAX, RCX);
+        __ j(OVERFLOW, &not_smi_or_overflow);
+        break;
+      }
+      case Token::kSUB: {
+        __ subq(RAX, RCX);
+        __ j(OVERFLOW, &not_smi_or_overflow);
+        break;
+      }
+      case Token::kEQ: {
+        Label done, is_true;
+        __ cmpq(RAX, RCX);
+        __ j(EQUAL, &is_true, Assembler::kNearJump);
+        __ LoadObject(RAX, Bool::False());
+        __ jmp(&done, Assembler::kNearJump);
+        __ Bind(&is_true);
+        __ LoadObject(RAX, Bool::True());
+        __ Bind(&done);
+        break;
+      }
+      default: UNIMPLEMENTED();
+    }
+    // Return past the call to lookup result.
+    intptr_t call_length = 2;  // call rcx
+    __ AddImmediate(Address(RSP, 0), Immediate(call_length));
+    __ ret();
+
+    __ Bind(&not_smi_or_overflow);
+  }
+
   Label loop, found, miss;
 
   __ movq(R13, FieldAddress(RBX, ICData::ic_data_offset()));
@@ -2166,12 +2212,14 @@ void StubCode::GenerateICLookupStub(Assembler* assembler) {
   __ testq(R9, R9);
   __ j(ZERO, &miss, Assembler::kNearJump);
 
-  const intptr_t entry_length = ICData::TestEntryLengthFor(1) * kWordSize;
+  const intptr_t entry_length =
+      ICData::TestEntryLengthFor(args_checked) * kWordSize;
   __ addq(R13, Immediate(entry_length));  // Next entry.
   __ jmp(&loop);
 
   __ Bind(&found);
-  const intptr_t target_offset = ICData::TargetIndexFor(1) * kWordSize;
+  const intptr_t target_offset =
+      ICData::TargetIndexFor(args_checked) * kWordSize;
   __ movq(RAX, Address(R13, target_offset));
   __ movq(RCX, FieldAddress(RAX, Function::entry_point_offset()));
   __ movq(CODE_REG, FieldAddress(RAX, Function::code_offset()));
@@ -2184,6 +2232,26 @@ 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_X64