deps: update V8 to 4.5.103.20

Update to the latest branch-head for V8 4.5. This version unships spread calls
and spread arrays and fixes a few issues.

Detailed information on the V8 commits contained herein:
https://github.com/v8/v8-git-mirror/commits/4.5.103.20

Note that there is a typo in the commit log that mistakenly calls it 4.5.103.15.
For posterity, 4.5.103.20 refers to
v8/v8@71d2ce6

Author: ofrobots

deps/v8/include/v8-version.h

@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 4
 #define V8_MINOR_VERSION 5
 #define V8_BUILD_NUMBER 103
-#define V8_PATCH_LEVEL 6
+#define V8_PATCH_LEVEL 20
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)

deps/v8/src/api-natives.cc

@@ -151,15 +151,6 @@ MaybeHandle<JSObject> ConfigureInstance(Isolate* isolate, Handle<JSObject> obj,
     PropertyAttributes attributes = details.attributes();
     PropertyKind kind = details.kind();
 
-    if (obj->map()->owns_descriptors() &&
-        obj->map()->instance_descriptors()->length() != 0 &&
-        obj->map()->instance_descriptors()->NumberOfSlackDescriptors() == 0 &&
-        TransitionArray::SearchTransition(obj->map(), kind, *name,
-                                          attributes) == NULL) {
-      Map::EnsureDescriptorSlack(handle(obj->map()),
-                                 data->number_of_properties() - c);
-    }
-
     if (kind == kData) {
       auto prop_data = handle(properties.get(i++), isolate);
 

deps/v8/src/arm/assembler-arm-inl.h

@@ -433,9 +433,7 @@ void Assembler::CheckBuffer() {
   if (buffer_space() <= kGap) {
     GrowBuffer();
   }
-  if (pc_offset() >= next_buffer_check_) {
-    CheckConstPool(false, true);
-  }
+  MaybeCheckConstPool();
 }
 
 

deps/v8/src/arm/assembler-arm.cc

@@ -1308,7 +1308,7 @@ void Assembler::addrmod5(Instr instr, CRegister crd, const MemOperand& x) {
 }
 
 
-int Assembler::branch_offset(Label* L, bool jump_elimination_allowed) {
+int Assembler::branch_offset(Label* L) {
   int target_pos;
   if (L->is_bound()) {
     target_pos = L->pos();
@@ -1377,6 +1377,24 @@ void Assembler::bx(Register target, Condition cond) {  // v5 and above, plus v4t
 }
 
 
+void Assembler::b(Label* L, Condition cond) {
+  CheckBuffer();
+  b(branch_offset(L), cond);
+}
+
+
+void Assembler::bl(Label* L, Condition cond) {
+  CheckBuffer();
+  bl(branch_offset(L), cond);
+}
+
+
+void Assembler::blx(Label* L) {
+  CheckBuffer();
+  blx(branch_offset(L));
+}
+
+
 // Data-processing instructions.
 
 void Assembler::and_(Register dst, Register src1, const Operand& src2,
@@ -3820,10 +3838,7 @@ void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
     bind(&size_check);
 
     // Emit jump over constant pool if necessary.
-    Label after_pool;
-    if (require_jump) {
-      b(&after_pool);
-    }
+    if (require_jump) b(size - kPcLoadDelta);
 
     // Put down constant pool marker "Undefined instruction".
     // The data size helps disassembly know what to print.
@@ -3907,10 +3922,6 @@ void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
     RecordComment("]");
 
     DCHECK_EQ(size, SizeOfCodeGeneratedSince(&size_check));
-
-    if (after_pool.is_linked()) {
-      bind(&after_pool);
-    }
   }
 
   // Since a constant pool was just emitted, move the check offset forward by

deps/v8/src/arm/assembler-arm.h

@@ -700,7 +700,7 @@ class Assembler : public AssemblerBase {
   // Returns the branch offset to the given label from the current code position
   // Links the label to the current position if it is still unbound
   // Manages the jump elimination optimization if the second parameter is true.
-  int branch_offset(Label* L, bool jump_elimination_allowed);
+  int branch_offset(Label* L);
 
   // Returns true if the given pc address is the start of a constant pool load
   // instruction sequence.
@@ -806,13 +806,11 @@ class Assembler : public AssemblerBase {
   void bx(Register target, Condition cond = al);  // v5 and above, plus v4t
 
   // Convenience branch instructions using labels
-  void b(Label* L, Condition cond = al)  {
-    b(branch_offset(L, cond == al), cond);
-  }
-  void b(Condition cond, Label* L)  { b(branch_offset(L, cond == al), cond); }
-  void bl(Label* L, Condition cond = al)  { bl(branch_offset(L, false), cond); }
-  void bl(Condition cond, Label* L)  { bl(branch_offset(L, false), cond); }
-  void blx(Label* L)  { blx(branch_offset(L, false)); }  // v5 and above
+  void b(Label* L, Condition cond = al);
+  void b(Condition cond, Label* L) { b(L, cond); }
+  void bl(Label* L, Condition cond = al);
+  void bl(Condition cond, Label* L) { bl(L, cond); }
+  void blx(Label* L);  // v5 and above
 
   // Data-processing instructions
 
@@ -1492,6 +1490,12 @@ class Assembler : public AssemblerBase {
   // Check if is time to emit a constant pool.
   void CheckConstPool(bool force_emit, bool require_jump);
 
+  void MaybeCheckConstPool() {
+    if (pc_offset() >= next_buffer_check_) {
+      CheckConstPool(false, true);
+    }
+  }
+
   int EmitEmbeddedConstantPool() {
     DCHECK(FLAG_enable_embedded_constant_pool);
     return constant_pool_builder_.Emit(this);

deps/v8/src/compiler/arm/code-generator-arm.cc

@@ -312,6 +312,8 @@ void CodeGenerator::AssembleDeconstructActivationRecord() {
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   ArmOperandConverter i(this, instr);
 
+  masm()->MaybeCheckConstPool();
+
   switch (ArchOpcodeField::decode(instr->opcode())) {
     case kArchCallCodeObject: {
       EnsureSpaceForLazyDeopt();

deps/v8/src/compiler/mips/code-generator-mips.cc

@@ -907,42 +907,32 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
     cc = FlagsConditionToConditionTst(branch->condition);
     __ And(at, i.InputRegister(0), i.InputOperand(1));
     __ Branch(tlabel, cc, at, Operand(zero_reg));
-
   } else if (instr->arch_opcode() == kMipsAddOvf ||
              instr->arch_opcode() == kMipsSubOvf) {
     // kMipsAddOvf, SubOvf emit negative result to 'kCompareReg' on overflow.
     cc = FlagsConditionToConditionOvf(branch->condition);
     __ Branch(tlabel, cc, kCompareReg, Operand(zero_reg));
-
   } else if (instr->arch_opcode() == kMipsCmp) {
     cc = FlagsConditionToConditionCmp(branch->condition);
     __ Branch(tlabel, cc, i.InputRegister(0), i.InputOperand(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
-
   } else if (instr->arch_opcode() == kMipsCmpS) {
     if (!convertCondition(branch->condition, cc)) {
       UNSUPPORTED_COND(kMips64CmpS, branch->condition);
     }
     __ BranchF32(tlabel, NULL, cc, i.InputSingleRegister(0),
                  i.InputSingleRegister(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
-
   } else if (instr->arch_opcode() == kMipsCmpD) {
     if (!convertCondition(branch->condition, cc)) {
       UNSUPPORTED_COND(kMips64CmpD, branch->condition);
     }
     __ BranchF64(tlabel, NULL, cc, i.InputDoubleRegister(0),
                  i.InputDoubleRegister(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
-
   } else {
     PrintF("AssembleArchBranch Unimplemented arch_opcode: %d\n",
            instr->arch_opcode());
     UNIMPLEMENTED();
   }
+  if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
 }
 
 

deps/v8/src/compiler/mips64/code-generator-mips64.cc

@@ -983,37 +983,30 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   } else if (instr->arch_opcode() == kMips64Dadd ||
              instr->arch_opcode() == kMips64Dsub) {
     cc = FlagsConditionToConditionOvf(branch->condition);
-
     __ dsra32(kScratchReg, i.OutputRegister(), 0);
     __ sra(at, i.OutputRegister(), 31);
     __ Branch(tlabel, cc, at, Operand(kScratchReg));
   } else if (instr->arch_opcode() == kMips64Cmp) {
     cc = FlagsConditionToConditionCmp(branch->condition);
     __ Branch(tlabel, cc, i.InputRegister(0), i.InputOperand(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
   } else if (instr->arch_opcode() == kMips64CmpS) {
     if (!convertCondition(branch->condition, cc)) {
       UNSUPPORTED_COND(kMips64CmpS, branch->condition);
     }
     __ BranchF32(tlabel, NULL, cc, i.InputSingleRegister(0),
                  i.InputSingleRegister(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
-
   } else if (instr->arch_opcode() == kMips64CmpD) {
     if (!convertCondition(branch->condition, cc)) {
       UNSUPPORTED_COND(kMips64CmpD, branch->condition);
     }
     __ BranchF64(tlabel, NULL, cc, i.InputDoubleRegister(0),
                  i.InputDoubleRegister(1));
-
-    if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
   } else {
     PrintF("AssembleArchBranch Unimplemented arch_opcode: %d\n",
            instr->arch_opcode());
     UNIMPLEMENTED();
   }
+  if (!branch->fallthru) __ Branch(flabel);  // no fallthru to flabel.
 }
 
 

deps/v8/src/flag-definitions.h

@@ -202,14 +202,14 @@ DEFINE_BOOL(legacy_const, true, "legacy semantics for const in sloppy mode")
 #define HARMONY_STAGED(V)                                       \
   V(harmony_tostring, "harmony toString")                       \
   V(harmony_concat_spreadable, "harmony isConcatSpreadable")    \
-  V(harmony_rest_parameters, "harmony rest parameters")
+  V(harmony_rest_parameters, "harmony rest parameters")         \
+  V(harmony_spreadcalls, "harmony spread-calls")                \
+  V(harmony_spread_arrays, "harmony spread in array literals")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                             \
   V(harmony_arrow_functions, "harmony arrow functions")                 \
   V(harmony_computed_property_names, "harmony computed property names") \
-  V(harmony_spreadcalls, "harmony spread-calls")                        \
-  V(harmony_spread_arrays, "harmony spread in array literals")          \
   V(harmony_unicode, "harmony unicode escapes")                         \
   V(harmony_object, "harmony Object methods")
 

deps/v8/src/heap/gc-idle-time-handler.cc

@@ -114,6 +114,10 @@ bool GCIdleTimeHandler::ShouldDoScavenge(
     size_t idle_time_in_ms, size_t new_space_size, size_t used_new_space_size,
     size_t scavenge_speed_in_bytes_per_ms,
     size_t new_space_allocation_throughput_in_bytes_per_ms) {
+  if (idle_time_in_ms >= kMinBackgroundIdleTime) {
+    // It is better to do full GC for the background tab.
+    return false;
+  }
   size_t new_space_allocation_limit =
       kMaxScheduledIdleTime * scavenge_speed_in_bytes_per_ms;
 
@@ -193,7 +197,10 @@ bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure(
 }
 
 
-GCIdleTimeAction GCIdleTimeHandler::NothingOrDone() {
+GCIdleTimeAction GCIdleTimeHandler::NothingOrDone(double idle_time_in_ms) {
+  if (idle_time_in_ms >= kMinBackgroundIdleTime) {
+    return GCIdleTimeAction::Nothing();
+  }
   if (idle_times_which_made_no_progress_ >= kMaxNoProgressIdleTimes) {
     return GCIdleTimeAction::Done();
   } else {
@@ -232,7 +239,7 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
   // get the right idle signal.
   if (ShouldDoContextDisposalMarkCompact(heap_state.contexts_disposed,
                                          heap_state.contexts_disposal_rate)) {
-    return NothingOrDone();
+    return NothingOrDone(idle_time_in_ms);
   }
 
   if (ShouldDoScavenge(
@@ -247,7 +254,7 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
     if (heap_state.sweeping_completed) {
       return GCIdleTimeAction::FinalizeSweeping();
     } else {
-      return NothingOrDone();
+      return NothingOrDone(idle_time_in_ms);
     }
   }