X64 Crankshaft: Add inline one-element cache for Instanceof.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
===================================================================
--- src/x64/code-stubs-x64.cc	(revision 7084)
+++ src/x64/code-stubs-x64.cc	(working copy)
@@ -3653,20 +3653,31 @@
 
 void InstanceofStub::Generate(MacroAssembler* masm) {
   // Implements "value instanceof function" operator.
-  // Expected input state:
+  // Expected input state with no inline cache:
   //   rsp[0] : return address
   //   rsp[1] : function pointer
   //   rsp[2] : value
+  // Expected input state with an inline one-element cache:
+  //   rsp[0] : return address
+  //   rsp[1] : offset from return address to location of inline cache
+  //   rsp[2] : function pointer
+  //   rsp[3] : value
   // Returns a bitwise zero to indicate that the value
   // is and instance of the function and anything else to
   // indicate that the value is not an instance.
 
+  static const int kOffsetToMapCheckValue = 5;
+  static const int kOffsetToResultValue = 21;

[Søren Thygesen Gjesse, 2011/03/09 15:21:53]

Please comment on what instructions these words represent.

+  static const unsigned int kWordBeforeMapCheckValue = 0xBA49FF78;
+  static const unsigned int kWordBeforeResultValue = 0x458B4909;
   // None of the flags are supported on X64.

[Søren Thygesen Gjesse, 2011/03/09 15:21:53]

This comment seems no longer valid. None -> Some? Args in registers not
supported - right?

-  ASSERT(flags_ == kNoFlags);
+  ASSERT(flags_ == kNoFlags || HasCallSiteInlineCheck());
+  int extra_stack_space = HasCallSiteInlineCheck() ? kPointerSize : 0;
 
   // Get the object - go slow case if it's a smi.
   Label slow;
-  __ movq(rax, Operand(rsp, 2 * kPointerSize));
+
+  __ movq(rax, Operand(rsp, 2 * kPointerSize + extra_stack_space));
   __ JumpIfSmi(rax, &slow);
 
   // Check that the left hand is a JS object. Leave its map in rax.
@@ -3676,19 +3687,23 @@
   __ j(above, &slow);
 
   // Get the prototype of the function.
-  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
+  __ movq(rdx, Operand(rsp, 1 * kPointerSize + extra_stack_space));
   // rdx is function, rax is map.
 
-  // Look up the function and the map in the instanceof cache.
-  NearLabel miss;
-  __ CompareRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
-  __ j(not_equal, &miss);
-  __ CompareRoot(rax, Heap::kInstanceofCacheMapRootIndex);
-  __ j(not_equal, &miss);
-  __ LoadRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
+  // If there is a call site cache don't look in the global cache, but do the
+  // real lookup and update the call site cache.
+  if (!HasCallSiteInlineCheck()) {
+    // Look up the function and the map in the instanceof cache.
+    NearLabel miss;
+    __ CompareRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
+    __ j(not_equal, &miss);
+    __ CompareRoot(rax, Heap::kInstanceofCacheMapRootIndex);
+    __ j(not_equal, &miss);
+    __ LoadRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
+    __ ret(2 * kPointerSize);
+    __ bind(&miss);
+  }
 
-  __ bind(&miss);
   __ TryGetFunctionPrototype(rdx, rbx, &slow);
 
   // Check that the function prototype is a JS object.
@@ -3702,8 +3717,19 @@
   //   rax is object map.
   //   rdx is function.
   //   rbx is function prototype.
-  __ StoreRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
-  __ StoreRoot(rax, Heap::kInstanceofCacheMapRootIndex);
+  if (!HasCallSiteInlineCheck()) {
+    __ StoreRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
+    __ StoreRoot(rax, Heap::kInstanceofCacheMapRootIndex);
+  } else {
+    __ movq(kScratchRegister, Operand(rsp, 0 * kPointerSize));
+    __ subq(kScratchRegister, Operand(rsp, 1 * kPointerSize));
+    __ movq(Operand(kScratchRegister, kOffsetToMapCheckValue), rax);
+    if (FLAG_debug_code) {
+      __ movl(rdi, Immediate(kWordBeforeMapCheckValue));
+      __ cmpl(Operand(kScratchRegister, kOffsetToMapCheckValue - 4), rdi);
+      __ Assert(equal, "InstanceofStub unexpected call site cache.");
+    }
+  }
 
   __ movq(rcx, FieldOperand(rax, Map::kPrototypeOffset));
 
@@ -3722,19 +3748,56 @@
   __ jmp(&loop);
 
   __ bind(&is_instance);
-  __ xorl(rax, rax);
-  // Store bitwise zero in the cache.  This is a Smi in GC terms.
-  STATIC_ASSERT(kSmiTag == 0);
-  __ StoreRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
+  if (!HasCallSiteInlineCheck()) {
+    __ xorl(rax, rax);
+    // Store bitwise zero in the cache.  This is a Smi in GC terms.
+    STATIC_ASSERT(kSmiTag == 0);
+    __ StoreRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
+  } else {
+    // Store offset of true in the root array at the inline check site.
+    ASSERT((Heap::kTrueValueRootIndex << kPointerSizeLog2) - kRootRegisterBias
+        == 0xB0 - 0x100);
+    __ movl(rax, Immediate(0xB0));  // TrueValue is at -10 * kPointerSize.
+    __ movq(kScratchRegister, Operand(rsp, 0 * kPointerSize));
+    __ subq(kScratchRegister, Operand(rsp, 1 * kPointerSize));
+    __ movb(Operand(kScratchRegister, kOffsetToResultValue), rax);
+    if (FLAG_debug_code) {
+      __ movl(rax, Immediate(kWordBeforeResultValue));
+      __ cmpl(Operand(kScratchRegister, kOffsetToResultValue - 4), rax);
+      __ Assert(equal, "InstanceofStub unexpected call site cache.");
+    }
+    __ xorl(rax, rax);
+  }
+  __ ret(2 * kPointerSize + extra_stack_space);
 
   __ bind(&is_not_instance);
-  // We have to store a non-zero value in the cache.
-  __ StoreRoot(kScratchRegister, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
+  if (!HasCallSiteInlineCheck()) {
+    // We have to store a non-zero value in the cache.
+    __ StoreRoot(kScratchRegister, Heap::kInstanceofCacheAnswerRootIndex);
+  } else {
+    // Store offset of false in the root array at the inline check site.
+    ASSERT((Heap::kFalseValueRootIndex << kPointerSizeLog2) - kRootRegisterBias
+        == 0xB8 - 0x100);
+    __ movl(rax, Immediate(0xB8));  // TrueValue is at -9 * kPointerSize.

[Søren Thygesen Gjesse, 2011/03/09 15:21:53]

TrueValue -> FalseValue

+    __ movq(kScratchRegister, Operand(rsp, 0 * kPointerSize));
+    __ subq(kScratchRegister, Operand(rsp, 1 * kPointerSize));
+    __ movb(Operand(kScratchRegister, kOffsetToResultValue), rax);
+    if (FLAG_debug_code) {
+      __ movl(rax, Immediate(kWordBeforeResultValue));
+      __ cmpl(Operand(kScratchRegister, kOffsetToResultValue - 4), rax);
+      __ Assert(equal, "InstanceofStub unexpected call site cache (mov)");
+    }
+  }
+  __ ret(2 * kPointerSize + extra_stack_space);
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
+  if (HasCallSiteInlineCheck()) {
+    // Remove extra value from the stack.
+    __ pop(rcx);
+    __ pop(rax);
+    __ push(rcx);
+  }
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }