Finegrainify namespacification
Move method out of generic dominators construction code
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10299 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index 2589c85..5f5a867 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -16,8 +16,7 @@
#include "llvm/Support/CFG.h"
#include "Support/DepthFirstIterator.h"
#include "Support/SetOperations.h"
-
-namespace llvm {
+using namespace llvm;
//===----------------------------------------------------------------------===//
// PostDominatorSet Implementation
@@ -110,6 +109,43 @@
static RegisterAnalysis<ImmediatePostDominators>
D("postidom", "Immediate Post-Dominators Construction", true);
+
+// calcIDoms - Calculate the immediate dominator mapping, given a set of
+// dominators for every basic block.
+void ImmediatePostDominators::calcIDoms(const DominatorSetBase &DS) {
+ // Loop over all of the nodes that have dominators... figuring out the IDOM
+ // for each node...
+ //
+ for (DominatorSet::const_iterator DI = DS.begin(), DEnd = DS.end();
+ DI != DEnd; ++DI) {
+ BasicBlock *BB = DI->first;
+ const DominatorSet::DomSetType &Dominators = DI->second;
+ unsigned DomSetSize = Dominators.size();
+ if (DomSetSize == 1) continue; // Root node... IDom = null
+
+ // Loop over all dominators of this node. This corresponds to looping over
+ // nodes in the dominator chain, looking for a node whose dominator set is
+ // equal to the current nodes, except that the current node does not exist
+ // in it. This means that it is one level higher in the dom chain than the
+ // current node, and it is our idom!
+ //
+ DominatorSet::DomSetType::const_iterator I = Dominators.begin();
+ DominatorSet::DomSetType::const_iterator End = Dominators.end();
+ for (; I != End; ++I) { // Iterate over dominators...
+ // All of our dominators should form a chain, where the number of elements
+ // in the dominator set indicates what level the node is at in the chain.
+ // We want the node immediately above us, so it will have an identical
+ // dominator set, except that BB will not dominate it... therefore it's
+ // dominator set size will be one less than BB's...
+ //
+ if (DS.getDominators(*I).size() == DomSetSize - 1) {
+ IDoms[BB] = *I;
+ break;
+ }
+ }
+ }
+}
+
//===----------------------------------------------------------------------===//
// PostDominatorTree Implementation
//===----------------------------------------------------------------------===//
@@ -217,4 +253,3 @@
void PostDominanceFrontier::stub() {
}
-} // End llvm namespace