v8::internal::HMarkUnreachableBlocksPhase Class Reference

#include <hydrogen-mark-unreachable.h>

Inheritance diagram for v8::internal::HMarkUnreachableBlocksPhase:

Collaboration diagram for v8::internal::HMarkUnreachableBlocksPhase:

Public Member Functions
	HMarkUnreachableBlocksPhase (HGraph *graph)
void	Run ()
Public Member Functions inherited from v8::internal::HPhase
	HPhase (const char *name, HGraph *graph)
	~HPhase ()

Private Member Functions
void	MarkUnreachableBlocks ()
	DISALLOW_COPY_AND_ASSIGN (HMarkUnreachableBlocksPhase)

Additional Inherited Members
Protected Member Functions inherited from v8::internal::HPhase
HGraph *	graph () const

Detailed Description

Definition at line 14 of file hydrogen-mark-unreachable.h.

Constructor & Destructor Documentation

HMarkUnreachableBlocksPhase()

v8::internal::HMarkUnreachableBlocksPhase::HMarkUnreachableBlocksPhase ( HGraph *  graph )

inlineexplicit

Definition at line 16 of file hydrogen-mark-unreachable.h.

      : HPhase("H_Mark unreachable blocks", graph) { }

Member Function Documentation

DISALLOW_COPY_AND_ASSIGN()

v8::internal::HMarkUnreachableBlocksPhase::DISALLOW_COPY_AND_ASSIGN ( HMarkUnreachableBlocksPhase  )

private

MarkUnreachableBlocks()

void v8::internal::HMarkUnreachableBlocksPhase::MarkUnreachableBlocks ( )

private

Definition at line 11 of file hydrogen-mark-unreachable.cc.

                                                        {
  // If there is unreachable code in the graph, propagate the unreachable marks
  // using a fixed-point iteration.
  bool changed = true;
  const ZoneList<HBasicBlock*>* blocks = graph()->blocks();
  while (changed) {
    changed = false;
    for (int i = 0; i < blocks->length(); i++) {
      HBasicBlock* block = blocks->at(i);
      if (!block->IsReachable()) continue;
      bool is_reachable = blocks->at(0) == block;
      for (HPredecessorIterator it(block); !it.Done(); it.Advance()) {
        HBasicBlock* predecessor = it.Current();
        // A block is reachable if one of its predecessors is reachable,
        // doesn't deoptimize and either is known to transfer control to the
        // block or has a control flow instruction for which the next block
        // cannot be determined.
        if (predecessor->IsReachable() && !predecessor->IsDeoptimizing()) {
          HBasicBlock* pred_succ;
          bool known_pred_succ =
              predecessor->end()->KnownSuccessorBlock(&pred_succ);
          if (!known_pred_succ || pred_succ == block) {
            is_reachable = true;
            break;
          }
        }
        if (block->is_osr_entry()) {
          is_reachable = true;
        }
      }
      if (!is_reachable) {
        block->MarkUnreachable();
        changed = true;
      }
    }
  }
}

References v8::internal::List< T, AllocationPolicy >::at(), and v8::internal::HPhase::graph().

Referenced by Run().

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Run()

void v8::internal::HMarkUnreachableBlocksPhase::Run

(

)

Definition at line 50 of file hydrogen-mark-unreachable.cc.

                                      {
  MarkUnreachableBlocks();
}

References MarkUnreachableBlocks().

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The documentation for this class was generated from the following files:

• /mnt/V8SourceCode/src/hydrogen-mark-unreachable.h
• /mnt/V8SourceCode/src/hydrogen-mark-unreachable.cc