C++ BlockSet::erase方法代码示例

void DeadCodeEliminationPass::runOnKernel(ir::IRKernel& k)
{
	report("Running dead code elimination on kernel " << k.name);
	reportE(REPORT_PTX, k);
	
	Analysis* dfgAnalysis = getAnalysis(Analysis::DataflowGraphAnalysis);
	assert(dfgAnalysis != 0);

	analysis::DataflowGraph& dfg =
		*static_cast<analysis::DataflowGraph*>(dfgAnalysis);
	
	assert(dfg.ssa() != analysis::DataflowGraph::SsaType::None);
	
	BlockSet blocks;
	
	report(" Starting by scanning all basic blocks");
	
	for(iterator block = dfg.begin(); block != dfg.end(); ++block)
	{
		report("  Queueing up BB_" << block->id());
		blocks.insert(block);
	}
	
	while(!blocks.empty())
	{
		iterator block = *blocks.begin();
		blocks.erase(blocks.begin());
	
		eliminateDeadInstructions(dfg, blocks, block);
	}
	
	report("Finished running dead code elimination on kernel " << k.name);
	reportE(REPORT_PTX, k);
}

    Shape *MakeLoop(BlockSet &Blocks, BlockSet& Entries, BlockSet &NextEntries) {
      // Find the inner blocks in this loop. Proceed backwards from the entries until
      // you reach a seen block, collecting as you go.
      BlockSet InnerBlocks;
      BlockSet Queue = Entries;
      while (Queue.size() > 0) {
        Block *Curr = *(Queue.begin());
        Queue.erase(Queue.begin());
        if (InnerBlocks.find(Curr) == InnerBlocks.end()) {
          // This element is new, mark it as inner and remove from outer
          InnerBlocks.insert(Curr);
          Blocks.erase(Curr);
          // Add the elements prior to it
          for (BlockBranchMap::iterator iter = Curr->BranchesIn.begin(); iter != Curr->BranchesIn.end(); iter++) {
            Queue.insert(iter->first);
          }
        }
      }
      assert(InnerBlocks.size() > 0);

      for (BlockSet::iterator iter = InnerBlocks.begin(); iter != InnerBlocks.end(); iter++) {
        Block *Curr = *iter;
        for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
          Block *Possible = iter->first;
          if (InnerBlocks.find(Possible) == InnerBlocks.end() &&
              NextEntries.find(Possible) == NextEntries.find(Possible)) {
            NextEntries.insert(Possible);
          }
        }
      }

      PrintDebug("creating loop block:\n");
      DebugDump(InnerBlocks, "  inner blocks:");
      DebugDump(Entries, "  inner entries:");
      DebugDump(Blocks, "  outer blocks:");
      DebugDump(NextEntries, "  outer entries:");

      // TODO: Optionally hoist additional blocks into the loop

      LoopShape *Loop = new LoopShape();
      Notice(Loop);

      // Solipsize the loop, replacing with break/continue and marking branches as Processed (will not affect later calculations)
      // A. Branches to the loop entries become a continue to this shape
      for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
        Solipsize(*iter, Branch::Continue, Loop, InnerBlocks);
      }
      // B. Branches to outside the loop (a next entry) become breaks on this shape
      for (BlockSet::iterator iter = NextEntries.begin(); iter != NextEntries.end(); iter++) {
        Solipsize(*iter, Branch::Break, Loop, InnerBlocks);
      }
      // Finish up
      Shape *Inner = Process(InnerBlocks, Entries, NULL);
      Loop->Inner = Inner;
      return Loop;
    }

 // If a block has multiple entries but no exits, and it is small enough, it is useful to split it.
 // A common example is a C++ function where everything ends up at a final exit block and does some
 // RAII cleanup. Without splitting, we will be forced to introduce labelled loops to allow
 // reaching the final block
 void SplitDeadEnds() {
   unsigned TotalCodeSize = 0;
   for (BlockSet::iterator iter = Live.begin(); iter != Live.end(); iter++) {
     Block *Curr = *iter;
     TotalCodeSize += strlen(Curr->Code);
   }
   BlockSet Splits;
   BlockSet Removed;
   //DebugDump(Live, "before");
   for (BlockSet::iterator iter = Live.begin(); iter != Live.end(); iter++) {
     Block *Original = *iter;
     if (Original->BranchesIn.size() <= 1 || Original->BranchesOut.size() > 0) continue; // only dead ends, for now
     if (contains(Original->BranchesOut, Original)) continue; // cannot split a looping node
     if (strlen(Original->Code)*(Original->BranchesIn.size()-1) > TotalCodeSize/5) continue; // if splitting increases raw code size by a significant amount, abort
     // Split the node (for simplicity, we replace all the blocks, even though we could have reused the original)
     PrintDebug("Splitting block %d\n", Original->Id);
     for (BlockSet::iterator iter = Original->BranchesIn.begin(); iter != Original->BranchesIn.end(); iter++) {
       Block *Prior = *iter;
       Block *Split = new Block(Original->Code, Original->BranchVar);
       Parent->AddBlock(Split);
       PrintDebug("  to %d\n", Split->Id);
       Split->BranchesIn.insert(Prior);
       Branch *Details = Prior->BranchesOut[Original];
       Prior->BranchesOut[Split] = new Branch(Details->Condition, Details->Code);
       Prior->BranchesOut.erase(Original);
       for (BlockBranchMap::iterator iter = Original->BranchesOut.begin(); iter != Original->BranchesOut.end(); iter++) {
         Block *Post = iter->first;
         Branch *Details = iter->second;
         Split->BranchesOut[Post] = new Branch(Details->Condition, Details->Code);
         Post->BranchesIn.insert(Split);
       }
       Splits.insert(Split);
       Removed.insert(Original);
     }
     for (BlockBranchMap::iterator iter = Original->BranchesOut.begin(); iter != Original->BranchesOut.end(); iter++) {
       Block *Post = iter->first;
       Post->BranchesIn.erase(Original);
     }
     //DebugDump(Live, "mid");
   }
   for (BlockSet::iterator iter = Splits.begin(); iter != Splits.end(); iter++) {
     Live.insert(*iter);
   }
   for (BlockSet::iterator iter = Removed.begin(); iter != Removed.end(); iter++) {
     Live.erase(*iter);
   }
   //DebugDump(Live, "after");
 }

 Shape *MakeMultiple(BlockSet &Blocks, BlockSet& Entries, BlockBlockSetMap& IndependentGroups, Shape *Prev, BlockSet &NextEntries) {
   PrintDebug("creating multiple block with %d inner groups\n", IndependentGroups.size());
   bool Fused = !!(Shape::IsSimple(Prev));
   MultipleShape *Multiple = new MultipleShape();
   Notice(Multiple);
   BlockSet CurrEntries;
   for (BlockBlockSetMap::iterator iter = IndependentGroups.begin(); iter != IndependentGroups.end(); iter++) {
     Block *CurrEntry = iter->first;
     BlockSet &CurrBlocks = iter->second;
     PrintDebug("  multiple group with entry %d:\n", CurrEntry->Id);
     DebugDump(CurrBlocks, "    ");
     // Create inner block
     CurrEntries.clear();
     CurrEntries.insert(CurrEntry);
     for (BlockSet::iterator iter = CurrBlocks.begin(); iter != CurrBlocks.end(); iter++) {
       Block *CurrInner = *iter;
       // Remove the block from the remaining blocks
       Blocks.erase(CurrInner);
       // Find new next entries and fix branches to them
       for (BlockBranchMap::iterator iter = CurrInner->BranchesOut.begin(); iter != CurrInner->BranchesOut.end();) {
         Block *CurrTarget = iter->first;
         BlockBranchMap::iterator Next = iter;
         Next++;
         if (CurrBlocks.find(CurrTarget) == CurrBlocks.end()) {
           NextEntries.insert(CurrTarget);
           Solipsize(CurrTarget, Branch::Break, Multiple, CurrBlocks); 
         }
         iter = Next; // increment carefully because Solipsize can remove us
       }
     }
     Multiple->InnerMap[CurrEntry] = Process(CurrBlocks, CurrEntries, NULL);
     // If we are not fused, then our entries will actually be checked
     if (!Fused) {
       CurrEntry->IsCheckedMultipleEntry = true;
     }
   }
   DebugDump(Blocks, "  remaining blocks after multiple:");
   // Add entries not handled as next entries, they are deferred
   for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
     Block *Entry = *iter;
     if (IndependentGroups.find(Entry) == IndependentGroups.end()) {
       NextEntries.insert(Entry);
     }
   }
   return Multiple;
 }

void ConstantPropagationPass::runOnKernel(ir::IRKernel& k)
{
	report("Running constant propagation on kernel " << k.name);
	
	Analysis* dfgAnalysis = getAnalysis("DataflowGraphAnalysis");
	assert(dfgAnalysis != 0);
	
	analysis::DataflowGraph& dfg =
		*static_cast<analysis::DataflowGraph*>(dfgAnalysis);
	
	dfg.convertToSSAType(analysis::DataflowGraph::Minimal);
	
	assert(dfg.ssa() == analysis::DataflowGraph::Minimal);
	
	BlockSet blocks;
	
	report(" Starting by scanning all basic blocks");
	
	for(iterator block = dfg.begin(); block != dfg.end(); ++block)
	{
		report("  Queueing up BB_" << block->id());
		blocks.insert(block);
	}
	
	while(!blocks.empty())
	{
		iterator block = *blocks.begin();
		blocks.erase(blocks.begin());
	
		eliminateRedundantInstructions(dfg, blocks, block);
	}

	report("Finished running constant propagation on kernel " << k.name);
	reportE(REPORT_PTX, k);

}

ControlFlowGraph::ConstBlockPointerVector
	ControlFlowGraph::executable_sequence() const {
	typedef std::unordered_set<const_iterator> BlockSet;
	ConstBlockPointerVector sequence;
	BlockSet unscheduled;

	for(const_iterator i = begin(); i != end(); ++i) {
		unscheduled.insert(i);
	}

	report("Getting executable sequence.");

	sequence.push_back(get_entry_block());
	unscheduled.erase(get_entry_block());
	report(" added " << get_entry_block()->label());

	while (!unscheduled.empty()) {
		if (sequence.back()->has_fallthrough_edge()) {
			const_edge_iterator fallthroughEdge 	
				= sequence.back()->get_fallthrough_edge();
			sequence.push_back(fallthroughEdge->tail);
			unscheduled.erase(fallthroughEdge->tail);
		}
		else {
			// find a new block, favor branch targets over random blocks
			const_iterator next = *unscheduled.begin();
			
			for(const_edge_pointer_iterator
				edge = sequence.back()->out_edges.begin();
				edge != sequence.back()->out_edges.end(); ++edge)
			{
				if(unscheduled.count((*edge)->tail) != 0)
				{
					next = (*edge)->tail;
				}
			}
			
			// rewind through fallthrough edges to find the beginning of the 
			// next chain of fall throughs
			report("  restarting at " << next->label());
			bool rewinding = true;
			while (rewinding) {
				rewinding = false;
				for (const_edge_pointer_iterator
					edge = next->in_edges.begin(); 
					edge != next->in_edges.end(); ++edge) {
					if ((*edge)->type == Edge::FallThrough) {
						assertM(unscheduled.count((*edge)->head) != 0, 
							(*edge)->head->label() 
							<< " has multiple fallthrough branches.");
						next = (*edge)->head;
						report("   rewinding to " << next->label());
						rewinding = true;
						break;
					}
				}
			}
			sequence.push_back(next);
			unscheduled.erase(next);
		}
		
		report(" added " << sequence.back()->label());
	}

	return sequence;
}

    Shape *MakeLoop(BlockSet &Blocks, BlockSet& Entries, BlockSet &NextEntries) {
      // Find the inner blocks in this loop. Proceed backwards from the entries until
      // you reach a seen block, collecting as you go.
      BlockSet InnerBlocks;
      BlockSet Queue = Entries;
      while (Queue.size() > 0) {
        Block *Curr = *(Queue.begin());
        Queue.erase(Queue.begin());
        if (!contains(InnerBlocks, Curr)) {
          // This element is new, mark it as inner and remove from outer
          InnerBlocks.insert(Curr);
          Blocks.erase(Curr);
          // Add the elements prior to it
          for (BlockSet::iterator iter = Curr->BranchesIn.begin(); iter != Curr->BranchesIn.end(); iter++) {
            Queue.insert(*iter);
          }
#if 0
          // Add elements it leads to, if they are dead ends. There is no reason not to hoist dead ends
          // into loops, as it can avoid multiple entries after the loop
          for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
            Block *Target = iter->first;
            if (Target->BranchesIn.size() <= 1 && Target->BranchesOut.size() == 0) {
              Queue.insert(Target);
            }
          }
#endif
        }
      }
      assert(InnerBlocks.size() > 0);

      for (BlockSet::iterator iter = InnerBlocks.begin(); iter != InnerBlocks.end(); iter++) {
        Block *Curr = *iter;
        for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
          Block *Possible = iter->first;
          if (!contains(InnerBlocks, Possible)) {
            NextEntries.insert(Possible);
          }
        }
      }

#if 0
      // We can avoid multiple next entries by hoisting them into the loop.
      if (NextEntries.size() > 1) {
        BlockBlockSetMap IndependentGroups;
        FindIndependentGroups(NextEntries, IndependentGroups, &InnerBlocks);

        while (IndependentGroups.size() > 0 && NextEntries.size() > 1) {
          Block *Min = NULL;
          int MinSize = 0;
          for (BlockBlockSetMap::iterator iter = IndependentGroups.begin(); iter != IndependentGroups.end(); iter++) {
            Block *Entry = iter->first;
            BlockSet &Blocks = iter->second;
            if (!Min || Blocks.size() < MinSize) { // TODO: code size, not # of blocks
              Min = Entry;
              MinSize = Blocks.size();
            }
          }
          // check how many new entries this would cause
          BlockSet &Hoisted = IndependentGroups[Min];
          bool abort = false;
          for (BlockSet::iterator iter = Hoisted.begin(); iter != Hoisted.end() && !abort; iter++) {
            Block *Curr = *iter;
            for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
              Block *Target = iter->first;
              if (Hoisted.find(Target) == Hoisted.end() && NextEntries.find(Target) == NextEntries.end()) {
                // abort this hoisting
                abort = true;
                break;
              }
            }
          }
          if (abort) {
            IndependentGroups.erase(Min);
            continue;
          }
          // hoist this entry
          PrintDebug("hoisting %d into loop\n", Min->Id);
          NextEntries.erase(Min);
          for (BlockSet::iterator iter = Hoisted.begin(); iter != Hoisted.end(); iter++) {
            Block *Curr = *iter;
            InnerBlocks.insert(Curr);
            Blocks.erase(Curr);
          }
          IndependentGroups.erase(Min);
        }
      }
#endif

      PrintDebug("creating loop block:\n");
      DebugDump(InnerBlocks, "  inner blocks:");
      DebugDump(Entries, "  inner entries:");
      DebugDump(Blocks, "  outer blocks:");
      DebugDump(NextEntries, "  outer entries:");

      LoopShape *Loop = new LoopShape();
      Notice(Loop);

      // Solipsize the loop, replacing with break/continue and marking branches as Processed (will not affect later calculations)
      // A. Branches to the loop entries become a continue to this shape
      for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
//.........这里部分代码省略.........