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      1 // Copyright 2015 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/interpreter/control-flow-builders.h"
      6 #include "src/objects-inl.h"
      7 
      8 namespace v8 {
      9 namespace internal {
     10 namespace interpreter {
     11 
     12 
     13 BreakableControlFlowBuilder::~BreakableControlFlowBuilder() {
     14   DCHECK(break_labels_.empty() || break_labels_.is_bound());
     15 }
     16 
     17 void BreakableControlFlowBuilder::BindBreakTarget() {
     18   break_labels_.Bind(builder());
     19 }
     20 
     21 void BreakableControlFlowBuilder::EmitJump(BytecodeLabels* sites) {
     22   builder()->Jump(sites->New());
     23 }
     24 
     25 void BreakableControlFlowBuilder::EmitJumpIfTrue(BytecodeLabels* sites) {
     26   builder()->JumpIfTrue(sites->New());
     27 }
     28 
     29 void BreakableControlFlowBuilder::EmitJumpIfFalse(BytecodeLabels* sites) {
     30   builder()->JumpIfFalse(sites->New());
     31 }
     32 
     33 void BreakableControlFlowBuilder::EmitJumpIfUndefined(BytecodeLabels* sites) {
     34   builder()->JumpIfUndefined(sites->New());
     35 }
     36 
     37 void BreakableControlFlowBuilder::EmitJumpIfNull(BytecodeLabels* sites) {
     38   builder()->JumpIfNull(sites->New());
     39 }
     40 
     41 
     42 void BlockBuilder::EndBlock() {
     43   builder()->Bind(&block_end_);
     44   BindBreakTarget();
     45 }
     46 
     47 LoopBuilder::~LoopBuilder() {
     48   DCHECK(continue_labels_.empty() || continue_labels_.is_bound());
     49   DCHECK(header_labels_.empty() || header_labels_.is_bound());
     50 }
     51 
     52 void LoopBuilder::LoopHeader(ZoneVector<BytecodeLabel>* additional_labels) {
     53   // Jumps from before the loop header into the loop violate ordering
     54   // requirements of bytecode basic blocks. The only entry into a loop
     55   // must be the loop header. Surely breaks is okay? Not if nested
     56   // and misplaced between the headers.
     57   DCHECK(break_labels_.empty() && continue_labels_.empty());
     58   builder()->Bind(&loop_header_);
     59   if (additional_labels != nullptr) {
     60     for (auto& label : *additional_labels) {
     61       builder()->Bind(&label);
     62     }
     63   }
     64 }
     65 
     66 void LoopBuilder::JumpToHeader(int loop_depth) {
     67   // Pass the proper loop nesting level to the backwards branch, to trigger
     68   // on-stack replacement when armed for the given loop nesting depth.
     69   int level = Min(loop_depth, AbstractCode::kMaxLoopNestingMarker - 1);
     70   // Loop must have closed form, i.e. all loop elements are within the loop,
     71   // the loop header precedes the body and next elements in the loop.
     72   DCHECK(loop_header_.is_bound());
     73   builder()->JumpLoop(&loop_header_, level);
     74 }
     75 
     76 void LoopBuilder::EndLoop() {
     77   BindBreakTarget();
     78   header_labels_.BindToLabel(builder(), loop_header_);
     79 }
     80 
     81 void LoopBuilder::BindContinueTarget() { continue_labels_.Bind(builder()); }
     82 
     83 SwitchBuilder::~SwitchBuilder() {
     84 #ifdef DEBUG
     85   for (auto site : case_sites_) {
     86     DCHECK(site.is_bound());
     87   }
     88 #endif
     89 }
     90 
     91 
     92 void SwitchBuilder::SetCaseTarget(int index) {
     93   BytecodeLabel& site = case_sites_.at(index);
     94   builder()->Bind(&site);
     95 }
     96 
     97 
     98 void TryCatchBuilder::BeginTry(Register context) {
     99   builder()->MarkTryBegin(handler_id_, context);
    100 }
    101 
    102 
    103 void TryCatchBuilder::EndTry() {
    104   builder()->MarkTryEnd(handler_id_);
    105   builder()->Jump(&exit_);
    106   builder()->Bind(&handler_);
    107   builder()->MarkHandler(handler_id_, catch_prediction_);
    108 }
    109 
    110 
    111 void TryCatchBuilder::EndCatch() { builder()->Bind(&exit_); }
    112 
    113 
    114 void TryFinallyBuilder::BeginTry(Register context) {
    115   builder()->MarkTryBegin(handler_id_, context);
    116 }
    117 
    118 
    119 void TryFinallyBuilder::LeaveTry() {
    120   builder()->Jump(finalization_sites_.New());
    121 }
    122 
    123 
    124 void TryFinallyBuilder::EndTry() {
    125   builder()->MarkTryEnd(handler_id_);
    126 }
    127 
    128 
    129 void TryFinallyBuilder::BeginHandler() {
    130   builder()->Bind(&handler_);
    131   builder()->MarkHandler(handler_id_, catch_prediction_);
    132 }
    133 
    134 void TryFinallyBuilder::BeginFinally() { finalization_sites_.Bind(builder()); }
    135 
    136 void TryFinallyBuilder::EndFinally() {
    137   // Nothing to be done here.
    138 }
    139 
    140 }  // namespace interpreter
    141 }  // namespace internal
    142 }  // namespace v8
    143