[TypeFeedbackVector] Root feedback vectors at function literal site.

src/builtins/ia32/builtins-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1010 matching lines @@
   // -----------------------------------
   // First lookup code, maybe we don't need to compile!
   Label gotta_call_runtime, gotta_call_runtime_no_stack;
   Label try_shared;
   Label loop_top, loop_bottom;
 
   Register closure = edi;
   Register new_target = edx;
   Register argument_count = eax;
 
+  // Do we have a valid feedback vector?
+  __ mov(ebx, FieldOperand(closure, JSFunction::kFeedbackVectorOffset));
+  __ mov(ebx, FieldOperand(ebx, Cell::kValueOffset));
+  __ JumpIfRoot(ebx, Heap::kUndefinedValueRootIndex,
+                &gotta_call_runtime_no_stack);
+
   __ push(argument_count);
   __ push(new_target);
   __ push(closure);
 
   Register map = argument_count;
   Register index = ebx;
   __ mov(map, FieldOperand(closure, JSFunction::kSharedFunctionInfoOffset));
   __ mov(map, FieldOperand(map, SharedFunctionInfo::kOptimizedCodeMapOffset));
   __ mov(index, FieldOperand(map, FixedArray::kLengthOffset));
   __ cmp(index, Immediate(Smi::FromInt(2)));
-  __ j(less, &gotta_call_runtime);
+  __ j(less, &try_shared);
 
-  // Find literals.
   // edx : native context
   // ebx : length / index
   // eax : optimized code map
   // stack[0] : new target
   // stack[4] : closure
   Register native_context = edx;
   __ mov(native_context, NativeContextOperand());
 
   __ bind(&loop_top);
   Register temp = edi;
 
   // Does the native context match?
   __ mov(temp, FieldOperand(map, index, times_half_pointer_size,
                             SharedFunctionInfo::kOffsetToPreviousContext));
   __ mov(temp, FieldOperand(temp, WeakCell::kValueOffset));
   __ cmp(temp, native_context);
   __ j(not_equal, &loop_bottom);
-  // Feedback vector available?
-  __ mov(temp, FieldOperand(map, index, times_half_pointer_size,
-                            SharedFunctionInfo::kOffsetToPreviousLiterals));
-  __ mov(temp, FieldOperand(temp, WeakCell::kValueOffset));
-  __ JumpIfSmi(temp, &gotta_call_runtime);
-
-  // Save the vector in the closure.
-  __ mov(ecx, Operand(esp, 0));
-  __ mov(FieldOperand(ecx, JSFunction::kFeedbackVectorOffset), temp);
-  __ push(index);
-  __ RecordWriteField(ecx, JSFunction::kFeedbackVectorOffset, temp, index,
-                      kDontSaveFPRegs, EMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
-  __ pop(index);
 
   // Code available?
   Register entry = ecx;
   __ mov(entry, FieldOperand(map, index, times_half_pointer_size,
                              SharedFunctionInfo::kOffsetToPreviousCachedCode));
   __ mov(entry, FieldOperand(entry, WeakCell::kValueOffset));
   __ JumpIfSmi(entry, &try_shared);
 
-  // Found literals and code. Get them into the closure and return.
+  // Found code. Get it into the closure and return.
   __ pop(closure);
   // Store code entry in the closure.
   __ lea(entry, FieldOperand(entry, Code::kHeaderSize));
   __ mov(FieldOperand(closure, JSFunction::kCodeEntryOffset), entry);
   __ RecordWriteCodeEntryField(closure, entry, eax);
 
   // Link the closure into the optimized function list.
   // ecx : code entry
   // edx : native context
   // edi : closure
@@ skipping 13 matching lines @@
   __ mov(closure, ebx);
   __ pop(new_target);
   __ pop(argument_count);
   __ jmp(entry);
 
   __ bind(&loop_bottom);
   __ sub(index, Immediate(Smi::FromInt(SharedFunctionInfo::kEntryLength)));
   __ cmp(index, Immediate(Smi::FromInt(1)));
   __ j(greater, &loop_top);
 
-  // We found neither literals nor code.
-  __ jmp(&gotta_call_runtime);
-
+  // We found no code.
   __ bind(&try_shared);
   __ pop(closure);
   __ pop(new_target);
   __ pop(argument_count);
   __ mov(entry, FieldOperand(closure, JSFunction::kSharedFunctionInfoOffset));
   // Is the shared function marked for tier up?
   __ test_b(FieldOperand(entry, SharedFunctionInfo::kMarkedForTierUpByteOffset),
             Immediate(1 << SharedFunctionInfo::kMarkedForTierUpBitWithinByte));
   __ j(not_zero, &gotta_call_runtime_no_stack);
 
@@ skipping 2244 matching lines @@
 
 void Builtins::Generate_InterpreterOnStackReplacement(MacroAssembler* masm) {
   Generate_OnStackReplacementHelper(masm, true);
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32