Vendor import of llvm trunk r126079:vendor/llvm/llvm-r126079

http://llvm.org/svn/llvm-project/llvm/trunk@126079

1 files changed, 137 insertions, 0 deletions

diff --git a/lib/Analysis/DominanceFrontier.cpp b/lib/Analysis/DominanceFrontier.cpp
new file mode 100644
index 000000000000..6de4e1e1d7de
--- /dev/null
+++ b/lib/Analysis/DominanceFrontier.cpp
@@ -0,0 +1,137 @@
+//===- DominanceFrontier.cpp - Dominance Frontier Calculation -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DominanceFrontier.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+char DominanceFrontier::ID = 0;
+INITIALIZE_PASS_BEGIN(DominanceFrontier, "domfrontier",
+                "Dominance Frontier Construction", true, true)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_END(DominanceFrontier, "domfrontier",
+                "Dominance Frontier Construction", true, true)
+
+namespace {
+  class DFCalculateWorkObject {
+  public:
+    DFCalculateWorkObject(BasicBlock *B, BasicBlock *P, 
+                          const DomTreeNode *N,
+                          const DomTreeNode *PN)
+    : currentBB(B), parentBB(P), Node(N), parentNode(PN) {}
+    BasicBlock *currentBB;
+    BasicBlock *parentBB;
+    const DomTreeNode *Node;
+    const DomTreeNode *parentNode;
+  };
+}
+
+const DominanceFrontier::DomSetType &
+DominanceFrontier::calculate(const DominatorTree &DT,
+                             const DomTreeNode *Node) {
+  BasicBlock *BB = Node->getBlock();
+  DomSetType *Result = NULL;
+
+  std::vector<DFCalculateWorkObject> workList;
+  SmallPtrSet<BasicBlock *, 32> visited;
+
+  workList.push_back(DFCalculateWorkObject(BB, NULL, Node, NULL));
+  do {
+    DFCalculateWorkObject *currentW = &workList.back();
+    assert (currentW && "Missing work object.");
+
+    BasicBlock *currentBB = currentW->currentBB;
+    BasicBlock *parentBB = currentW->parentBB;
+    const DomTreeNode *currentNode = currentW->Node;
+    const DomTreeNode *parentNode = currentW->parentNode;
+    assert (currentBB && "Invalid work object. Missing current Basic Block");
+    assert (currentNode && "Invalid work object. Missing current Node");
+    DomSetType &S = Frontiers[currentBB];
+
+    // Visit each block only once.
+    if (visited.count(currentBB) == 0) {
+      visited.insert(currentBB);
+
+      // Loop over CFG successors to calculate DFlocal[currentNode]
+      for (succ_iterator SI = succ_begin(currentBB), SE = succ_end(currentBB);
+           SI != SE; ++SI) {
+        // Does Node immediately dominate this successor?
+        if (DT[*SI]->getIDom() != currentNode)
+          S.insert(*SI);
+      }
+    }
+
+    // At this point, S is DFlocal.  Now we union in DFup's of our children...
+    // Loop through and visit the nodes that Node immediately dominates (Node's
+    // children in the IDomTree)
+    bool visitChild = false;
+    for (DomTreeNode::const_iterator NI = currentNode->begin(), 
+           NE = currentNode->end(); NI != NE; ++NI) {
+      DomTreeNode *IDominee = *NI;
+      BasicBlock *childBB = IDominee->getBlock();
+      if (visited.count(childBB) == 0) {
+        workList.push_back(DFCalculateWorkObject(childBB, currentBB,
+                                                 IDominee, currentNode));
+        visitChild = true;
+      }
+    }
+
+    // If all children are visited or there is any child then pop this block
+    // from the workList.
+    if (!visitChild) {
+
+      if (!parentBB) {
+        Result = &S;
+        break;
+      }
+
+      DomSetType::const_iterator CDFI = S.begin(), CDFE = S.end();
+      DomSetType &parentSet = Frontiers[parentBB];
+      for (; CDFI != CDFE; ++CDFI) {
+        if (!DT.properlyDominates(parentNode, DT[*CDFI]))
+          parentSet.insert(*CDFI);
+      }
+      workList.pop_back();
+    }
+
+  } while (!workList.empty());
+
+  return *Result;
+}
+
+void DominanceFrontierBase::print(raw_ostream &OS, const Module* ) const {
+  for (const_iterator I = begin(), E = end(); I != E; ++I) {
+    OS << "  DomFrontier for BB ";
+    if (I->first)
+      WriteAsOperand(OS, I->first, false);
+    else
+      OS << " <<exit node>>";
+    OS << " is:\t";
+    
+    const std::set<BasicBlock*> &BBs = I->second;
+    
+    for (std::set<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
+         I != E; ++I) {
+      OS << ' ';
+      if (*I)
+        WriteAsOperand(OS, *I, false);
+      else
+        OS << "<<exit node>>";
+    }
+    OS << "\n";
+  }
+}
+
+void DominanceFrontierBase::dump() const {
+  print(dbgs());
+}
+