[TypeFeedbackVector] Root feedback vectors at function literal site.

src/builtins/ppc/builtins-ppc.cc

 // Copyright 2014 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_PPC
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1346 matching lines @@
   //  -- r4 : target function (preserved for callee)
   // -----------------------------------
   // First lookup code, maybe we don't need to compile!
   Label gotta_call_runtime;
   Label try_shared;
   Label loop_top, loop_bottom;
 
   Register closure = r4;
   Register map = r9;
   Register index = r5;
+
+  // Do we have a valid feedback vector?
+  __ LoadP(index, FieldMemOperand(closure, JSFunction::kLiteralsOffset));
+  __ LoadP(index, FieldMemOperand(index, LiteralsArray::kFeedbackVectorOffset));
+  __ JumpIfRoot(index, Heap::kUndefinedValueRootIndex, &gotta_call_runtime);
+
   __ LoadP(map,
            FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
   __ LoadP(map,
            FieldMemOperand(map, SharedFunctionInfo::kOptimizedCodeMapOffset));
   __ LoadP(index, FieldMemOperand(map, FixedArray::kLengthOffset));
   __ CmpSmiLiteral(index, Smi::FromInt(2), r0);
   __ blt(&gotta_call_runtime);
 
-  // Find literals.
   // r10 : native context
   // r5  : length / index
   // r9  : optimized code map
   // r6  : new target
   // r4  : closure
   Register native_context = r10;
   __ LoadP(native_context, NativeContextMemOperand());
 
   __ bind(&loop_top);
   Register temp = r11;
   Register array_pointer = r8;
 
   // Does the native context match?
   __ SmiToPtrArrayOffset(array_pointer, index);
   __ add(array_pointer, map, array_pointer);
   __ LoadP(temp, FieldMemOperand(array_pointer,
                                  SharedFunctionInfo::kOffsetToPreviousContext));
   __ LoadP(temp, FieldMemOperand(temp, WeakCell::kValueOffset));
   __ cmp(temp, native_context);
   __ bne(&loop_bottom);
-  // Feedback vector available?
-  __ LoadP(temp,
-           FieldMemOperand(array_pointer,
-                           SharedFunctionInfo::kOffsetToPreviousLiterals));
-  __ LoadP(temp, FieldMemOperand(temp, WeakCell::kValueOffset));
-  __ JumpIfSmi(temp, &gotta_call_runtime);
-
-  // Save the feedback vector in the closure.
-  __ StoreP(temp, FieldMemOperand(closure, JSFunction::kFeedbackVectorOffset),
-            r0);
-  __ RecordWriteField(closure, JSFunction::kFeedbackVectorOffset, temp, r7,
-                      kLRHasNotBeenSaved, kDontSaveFPRegs, EMIT_REMEMBERED_SET,
-                      OMIT_SMI_CHECK);
 
   // Code available?
   Register entry = r7;
   __ LoadP(entry,
            FieldMemOperand(array_pointer,
                            SharedFunctionInfo::kOffsetToPreviousCachedCode));
   __ LoadP(entry, FieldMemOperand(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.
   // Store code entry in the closure.
   __ addi(entry, entry, Operand(Code::kHeaderSize - kHeapObjectTag));
   __ StoreP(entry, FieldMemOperand(closure, JSFunction::kCodeEntryOffset), r0);
   __ RecordWriteCodeEntryField(closure, entry, r8);
 
   // Link the closure into the optimized function list.
   // r7 : code entry
   // r10: native context
   // r4 : closure
   __ LoadP(
@@ skipping 13 matching lines @@
   __ RecordWriteContextSlot(native_context, function_list_offset, r8, temp,
                             kLRHasNotBeenSaved, kDontSaveFPRegs);
   __ JumpToJSEntry(entry);
 
   __ bind(&loop_bottom);
   __ SubSmiLiteral(index, index, Smi::FromInt(SharedFunctionInfo::kEntryLength),
                    r0);
   __ CmpSmiLiteral(index, Smi::FromInt(1), r0);
   __ bgt(&loop_top);
 
-  // We found neither literals nor code.
+  // We found no code.
   __ b(&gotta_call_runtime);
 
   __ bind(&try_shared);
   __ LoadP(entry,
            FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
   // Is the shared function marked for tier up?
   __ lbz(r8, FieldMemOperand(entry,
                              SharedFunctionInfo::kMarkedForTierUpByteOffset));
   __ TestBit(r8, SharedFunctionInfo::kMarkedForTierUpBitWithinByte, r0);
   __ bne(&gotta_call_runtime, cr0);
@@ skipping 1742 matching lines @@
     __ CallRuntime(Runtime::kThrowStackOverflow);
     __ bkpt(0);
   }
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC