[objects] Remove obsolete fields for old OSR support.

R=rmcilroy@chromium.org
BUG=v8:6409

Change-Id: Ib8bb85674f63fed47aa55a775eaade6b14d60f2e
Reviewed-on: https://chromium-review.googlesource.com/654040Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47873}

src/objects-inl.h

@@ -3821,20 +3821,6 @@ void Code::set_has_reloc_info_for_serialization(bool value) {
   WRITE_UINT32_FIELD(this, kFullCodeFlags, flags);
 }
 
-int Code::allow_osr_at_loop_nesting_level() const {
-  DCHECK_EQ(FUNCTION, kind());
-  int fields = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
-  return AllowOSRAtLoopNestingLevelField::decode(fields);
-}
-
-
-void Code::set_allow_osr_at_loop_nesting_level(int level) {
-  DCHECK_EQ(FUNCTION, kind());
-  DCHECK(level >= 0 && level <= AbstractCode::kMaxLoopNestingMarker);
-  int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
-  int updated = AllowOSRAtLoopNestingLevelField::update(previous, level);
-  WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
-}
 
 int Code::builtin_index() const {
   int index = READ_INT_FIELD(this, kBuiltinIndexOffset);
@@ -3880,27 +3866,6 @@ void Code::set_safepoint_table_offset(unsigned offset) {
   WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
 }
 
-unsigned Code::back_edge_table_offset() const {
-  DCHECK_EQ(FUNCTION, kind());
-  return BackEdgeTableOffsetField::decode(
-      READ_UINT32_FIELD(this, kKindSpecificFlags2Offset)) << kPointerSizeLog2;
-}
-
-
-void Code::set_back_edge_table_offset(unsigned offset) {
-  DCHECK_EQ(FUNCTION, kind());
-  DCHECK(IsAligned(offset, static_cast<unsigned>(kPointerSize)));
-  offset = offset >> kPointerSizeLog2;
-  int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
-  int updated = BackEdgeTableOffsetField::update(previous, offset);
-  WRITE_UINT32_FIELD(this, kKindSpecificFlags2Offset, updated);
-}
-
-bool Code::back_edges_patched_for_osr() const {
-  DCHECK_EQ(FUNCTION, kind());
-  return allow_osr_at_loop_nesting_level() > 0;
-}
-
 
 bool Code::marked_for_deoptimization() const {
   DCHECK(kind() == OPTIMIZED_FUNCTION);

src/objects.cc

@@ -14565,16 +14565,12 @@ void Code::Disassemble(const char* name, std::ostream& os) {  // NOLINT
     int size = instruction_size();
     int safepoint_offset =
         is_turbofanned() ? static_cast<int>(safepoint_table_offset()) : size;
-    int back_edge_offset = (kind() == Code::FUNCTION)
-                               ? static_cast<int>(back_edge_table_offset())
-                               : size;
     int constant_pool_offset = FLAG_enable_embedded_constant_pool
                                    ? this->constant_pool_offset()
                                    : size;
 
     // Stop before reaching any embedded tables
-    int code_size = Min(safepoint_offset, back_edge_offset);
-    code_size = Min(code_size, constant_pool_offset);
+    int code_size = Min(safepoint_offset, constant_pool_offset);
     byte* begin = instruction_start();
     byte* end = begin + code_size;
     Disassembler::Decode(isolate, &os, begin, end, this);

src/objects.h

@@ -3805,13 +3805,6 @@ class Code: public HeapObject {
   inline bool has_reloc_info_for_serialization() const;
   inline void set_has_reloc_info_for_serialization(bool value);
 
-  // [allow_osr_at_loop_nesting_level]: For FUNCTION kind, tells for
-  // how long the function has been marked for OSR and therefore which
-  // level of loop nesting we are willing to do on-stack replacement
-  // for.
-  inline void set_allow_osr_at_loop_nesting_level(int level);
-  inline int allow_osr_at_loop_nesting_level() const;
-
   // [builtin_index]: For builtins, tells which builtin index the code object
   // has. Note that builtins can have a code kind other than BUILTIN. The
   // builtin index is a non-negative integer for builtins, and -1 otherwise.
@@ -3829,13 +3822,6 @@ class Code: public HeapObject {
   inline unsigned safepoint_table_offset() const;
   inline void set_safepoint_table_offset(unsigned offset);
 
-  // [back_edge_table_start]: For kind FUNCTION, the offset in the
-  // instruction stream where the back edge table starts.
-  inline unsigned back_edge_table_offset() const;
-  inline void set_back_edge_table_offset(unsigned offset);
-
-  inline bool back_edges_patched_for_osr() const;
-
   // [marked_for_deoptimization]: For kind OPTIMIZED_FUNCTION tells whether
   // the code is going to be deoptimized because of dead embedded maps.
   inline bool marked_for_deoptimization() const;
@@ -4053,9 +4039,6 @@ class Code: public HeapObject {
   static const int kTrapHandlerIndex = kBuiltinIndexOffset + kIntSize;
   static const int kHeaderPaddingStart = kTrapHandlerIndex + kPointerSize;
 
-  enum TrapFields { kTrapCodeOffset, kTrapLandingOffset, kTrapDataSize };
-
-
   // Add padding to align the instruction start following right after
   // the Code object header.
   static const int kHeaderSize =
@@ -4129,12 +4112,6 @@ class Code: public HeapObject {
       kSafepointTableOffsetFirstBit,
       kSafepointTableOffsetBitCount> {};  // NOLINT
 
-  // KindSpecificFlags2 layout (FUNCTION)
-  class BackEdgeTableOffsetField
-      : public BitField<int, kHasTaggedStackBit + 1, 27> {};  // NOLINT
-  class AllowOSRAtLoopNestingLevelField
-      : public BitField<int, kHasTaggedStackBit + 1 + 27, 4> {};  // NOLINT
-
   static const int kArgumentsBits = 16;
   static const int kMaxArguments = (1 << kArgumentsBits) - 1;
 
@@ -4203,8 +4180,6 @@ class AbstractCode : public HeapObject {
   // Max loop nesting marker used to postpose OSR. We don't take loop
   // nesting that is deeper than 5 levels into account.
   static const int kMaxLoopNestingMarker = 6;
-  STATIC_ASSERT(Code::AllowOSRAtLoopNestingLevelField::kMax >=
-                kMaxLoopNestingMarker);
 };
 
 // Dependent code is a singly linked list of fixed arrays. Each array contains

test/cctest/test-compiler.cc

@@ -649,9 +649,7 @@ static void CheckCodeForUnsafeLiteral(Handle<JSFunction> f) {
 
   if (f->code()->kind() == Code::FUNCTION) {
     Address pc = f->code()->instruction_start();
-    int decode_size =
-        Min(f->code()->instruction_size(),
-            static_cast<int>(f->code()->back_edge_table_offset()));
+    int decode_size = f->code()->instruction_size();
     if (FLAG_enable_embedded_constant_pool) {
       decode_size = Min(decode_size, f->code()->constant_pool_offset());
     }