[TypeFeedbackVector] Root feedback vectors at function literal site.

src/builtins/s390/builtins-s390.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_S390
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1351 matching lines @@
   //  -- r3 : 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 = r3;
   Register map = r8;
   Register index = r4;
+
+  // 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.
   // r9 : native context
   // r4  : length / index
   // r8  : optimized code map
   // r5  : new target
   // r3  : closure
   Register native_context = r9;
   __ LoadP(native_context, NativeContextMemOperand());
 
   __ bind(&loop_top);
   Register temp = r1;
   Register array_pointer = r7;
 
   // Does the native context match?
   __ SmiToPtrArrayOffset(array_pointer, index);
   __ AddP(array_pointer, map, array_pointer);
   __ LoadP(temp, FieldMemOperand(array_pointer,
                                  SharedFunctionInfo::kOffsetToPreviousContext));
   __ LoadP(temp, FieldMemOperand(temp, WeakCell::kValueOffset));
   __ CmpP(temp, native_context);
   __ bne(&loop_bottom, Label::kNear);
-  // 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, r6,
-                      kLRHasNotBeenSaved, kDontSaveFPRegs, EMIT_REMEMBERED_SET,
-                      OMIT_SMI_CHECK);
 
   // Code available?
   Register entry = r6;
   __ 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.
   __ AddP(entry, entry, Operand(Code::kHeaderSize - kHeapObjectTag));
   __ StoreP(entry, FieldMemOperand(closure, JSFunction::kCodeEntryOffset), r0);
   __ RecordWriteCodeEntryField(closure, entry, r7);
 
   // Link the closure into the optimized function list.
   // r6 : code entry
   // r9: native context
   // r3 : closure
   __ LoadP(
@@ skipping 13 matching lines @@
   __ RecordWriteContextSlot(native_context, function_list_offset, r7, 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?
   __ LoadlB(temp, FieldMemOperand(
                       entry, SharedFunctionInfo::kMarkedForTierUpByteOffset));
   __ TestBit(temp, SharedFunctionInfo::kMarkedForTierUpBitWithinByte, r0);
   __ bne(&gotta_call_runtime);
@@ skipping 1749 matching lines @@
     __ bkpt(0);
   }
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390