Implement inlining of instanceof tests on ARM.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 3670765a61223bf20f6c5178edb1396cd3296dec..1242c9ffd26af9fd9b55fa3cacadfdae7eeacd73 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2893,37 +2893,46 @@ void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
 }
 
 
-// This stub performs an instanceof, calling the builtin function if
-// necessary.  Uses r1 for the object, r0 for the function that it may
-// be an instance of (these are fetched from the stack).
+// Uses registers r0 to r5. Expected input is
+// function in r0 (or at sp+1*ptrsz) and object in
+// r1 (or at sp), depending on whether or not
+// args_in_registers() is true.
 void InstanceofStub::Generate(MacroAssembler* masm) {
-  // Get the object - slow case for smis (we may need to throw an exception
-  // depending on the rhs).
-  Label slow, loop, is_instance, is_not_instance;
-  __ ldr(r0, MemOperand(sp, 1 * kPointerSize));
-  __ BranchOnSmi(r0, &slow);
+  // Fixed register usage throughout the stub:
+  const Register object = r1; // Object (lhs).
+  const Register map = r3; // Map of the object.
+  const Register function = r0; // Function (rhs).
+  const Register prototype = r4; // Prototype of the function.
+  const Register scratch = r2;
+  const Register scratch2 = r5; // Used for IncrementCounter.
+  const Register result = r0;

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

I don't think an alias for the result is required (when it is r0) - just use r0
there.

+  Label slow, loop, is_instance, is_not_instance, not_js_object;
+  if (!args_in_registers()) {
+    __ ldr(function, MemOperand(sp, 1 * kPointerSize));
+    __ ldr(object, MemOperand(sp, 0));
+  }
+  __ BranchOnSmi(function, &slow);
 
-  // Check that the left hand is a JS object and put map in r3.
-  __ CompareObjectType(r0, r3, r2, FIRST_JS_OBJECT_TYPE);
+  // Check that the left hand is a JS object, load map,
+  // and type into scratch

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

How about implementing IsObjectJSObjectType in the ARM macro assembler as well?

[Karl Klose, 2010/12/21 08:56:37]

Done.

+  __ CompareObjectType(function, map, scratch, FIRST_JS_OBJECT_TYPE);
   __ b(lt, &slow);
-  __ cmp(r2, Operand(LAST_JS_OBJECT_TYPE));
+  __ cmp(scratch, Operand(LAST_JS_OBJECT_TYPE));
   __ b(gt, &slow);
 
-  // Get the prototype of the function (r4 is result, r2 is scratch).
-  __ ldr(r1, MemOperand(sp, 0));
-  // r1 is function, r3 is map.
-
   // Look up the function and the map in the instanceof cache.
   Label miss;
   __ LoadRoot(ip, Heap::kInstanceofCacheFunctionRootIndex);
-  __ cmp(r1, ip);
+  __ cmp(object, ip);
   __ b(ne, &miss);
   __ LoadRoot(ip, Heap::kInstanceofCacheMapRootIndex);
-  __ cmp(r3, ip);
+  __ cmp(map, ip);
   __ b(ne, &miss);
-  __ LoadRoot(r0, Heap::kInstanceofCacheAnswerRootIndex);
-  __ pop();
-  __ pop();
+  __ LoadRoot(function, Heap::kInstanceofCacheAnswerRootIndex);
+  if (!args_in_registers()) {

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

Use Drop from the ARM macro assembler to drop two elements from the stack
(several times below).

[Karl Klose, 2010/12/21 08:56:37]

Done.

+    __ pop();
+    __ pop();
+  }

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

Use Ret from the ARM macro assembler. I suggest you add a Ret(int drop) function
to the ARM macro assembler to combine the Drop() and Ret().

[Karl Klose, 2010/12/21 08:56:37]

Done.

   __ mov(pc, Operand(lr));
 
   __ bind(&miss);

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

You should use the register aliases created throughout all the code.

[Karl Klose, 2010/12/21 08:56:37]

Done.

@@ -2957,17 +2966,70 @@ void InstanceofStub::Generate(MacroAssembler* masm) {
   __ bind(&is_instance);
   __ mov(r0, Operand(Smi::FromInt(0)));
   __ StoreRoot(r0, Heap::kInstanceofCacheAnswerRootIndex);
-  __ pop();
-  __ pop();
+  if (!args_in_registers()) {
+    __ pop();
+    __ pop();
+  }
   __ mov(pc, Operand(lr));  // Return.
 
   __ bind(&is_not_instance);
   __ mov(r0, Operand(Smi::FromInt(1)));
   __ StoreRoot(r0, Heap::kInstanceofCacheAnswerRootIndex);
-  __ pop();
-  __ pop();
+  if (!args_in_registers()) {
+    __ pop();
+    __ pop();
+  }
   __ mov(pc, Operand(lr));  // Return.
 
+  Label object_not_null, object_not_null_or_smi;
+  __ bind(&not_js_object);
+  // Before null, smi and string value checks, check that the rhs is a function
+  // as for a non-function rhs an exception needs to be thrown.
+  __ tst(function, Operand(kSmiTagMask));

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

The ARM macro assembler has BranchOnSmi.

[Karl Klose, 2010/12/21 08:56:37]

Done.

+  __ b(eq, &slow);
+  __ CompareObjectType(function, map, scratch, JS_FUNCTION_TYPE);
+  __ b(ne, &slow);
+
+  // Null is not instance of anything.
+  __ cmp(scratch, Operand(Factory::null_value()));
+  __ b(ne, &object_not_null);
+  __ mov(result, Operand(Smi::FromInt(1)));
+  if (!args_in_registers()) {
+    __ pop();
+    __ pop();
+  }
+  __ mov(pc, Operand(lr));  // return
+
+  __ bind(&object_not_null);
+  // Smi values are not instances of anything.
+  __ tst(object, Operand(kSmiTagMask));

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

The ARM macro assembler has BranchOnNotSmi.

[Karl Klose, 2010/12/21 08:56:37]

Done.

+  __ b(nz, &object_not_null_or_smi);
+  __ mov(result, Operand(Smi::FromInt(1)));
+  if (!args_in_registers()) {
+    __ pop();
+    __ pop();
+  }
+  __ mov(pc, Operand(lr));  // return
+
+  __ bind(&object_not_null_or_smi);
+  // String values are not instances of anything.

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

Please implement IsObjectStringType in ARM macro assembler.

[Karl Klose, 2010/12/21 08:56:37]

Done.

+  __ ldr(scratch, FieldMemOperand(object, HeapObject::kMapOffset));
+  __ ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+  ASSERT(kNotStringTag != 0);
+  __ tst(scratch, Operand(kIsNotStringMask));
+  __ b(nz, &slow);
+  __ IncrementCounter(&Counters::instance_of_stub_false_string,

[Søren Thygesen Gjesse, 2010/12/20 13:03:25]

You can leave out all the counters. Then you don't need scratch2.

[Karl Klose, 2010/12/21 08:56:37]

Done.

+                      1,
+                      scratch,
+                      scratch2);
+
+  __ mov(result, Operand(Smi::FromInt(1)));
+  if (!args_in_registers()) {
+    __ pop();
+    __ pop();
+  }
+  __ mov(pc, Operand(lr));  // return
+
   // Slow-case.  Tail call builtin.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_JS);