[llvm-commits] [llvm] r49768 - in /llvm/trunk: include/llvm/Analysis/DominatorInternals.h include/llvm/Analysis/Dominators.h lib/Analysis/PostDominators.cpp lib/VMCore/Dominators.cpp
Owen Anderson
resistor at mac.com
Tue Apr 15 21:21:16 PDT 2008
Author: resistor
Date: Tue Apr 15 23:21:16 2008
New Revision: 49768
URL: http://llvm.org/viewvc/llvm-project?rev=49768&view=rev
Log:
Major repairs to the post-dominators implementation. Patch from Florian Brandner!
Modified:
llvm/trunk/include/llvm/Analysis/DominatorInternals.h
llvm/trunk/include/llvm/Analysis/Dominators.h
llvm/trunk/lib/Analysis/PostDominators.cpp
llvm/trunk/lib/VMCore/Dominators.cpp
Modified: llvm/trunk/include/llvm/Analysis/DominatorInternals.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/DominatorInternals.h?rev=49768&r1=49767&r2=49768&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/DominatorInternals.h (original)
+++ llvm/trunk/include/llvm/Analysis/DominatorInternals.h Tue Apr 15 23:21:16 2008
@@ -42,7 +42,7 @@
// documentation purposes.
#if 0
InfoRec &VInfo = DT.Info[DT.Roots[i]];
- VInfo.Semi = ++N;
+ VInfo.DFSNum = VInfo.Semi = ++N;
VInfo.Label = V;
Vertex.push_back(V); // Vertex[n] = V;
@@ -58,6 +58,8 @@
}
}
#else
+ bool IsChilOfArtificialExit = (N != 0);
+
std::vector<std::pair<typename GraphT::NodeType*,
typename GraphT::ChildIteratorType> > Worklist;
Worklist.push_back(std::make_pair(V, GraphT::child_begin(V)));
@@ -65,19 +67,29 @@
typename GraphT::NodeType* BB = Worklist.back().first;
typename GraphT::ChildIteratorType NextSucc = Worklist.back().second;
+ typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
+ DT.Info[BB];
+
// First time we visited this BB?
if (NextSucc == GraphT::child_begin(BB)) {
- typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
- DT.Info[BB];
- BBInfo.Semi = ++N;
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
BBInfo.Label = BB;
DT.Vertex.push_back(BB); // Vertex[n] = V;
//BBInfo[V].Ancestor = 0; // Ancestor[n] = 0
//BBInfo[V].Child = 0; // Child[v] = 0
BBInfo.Size = 1; // Size[v] = 1
+
+ if (IsChilOfArtificialExit)
+ BBInfo.Parent = 1;
+
+ IsChilOfArtificialExit = false;
}
-
+
+ // store the DFS number of the current BB - the reference to BBInfo might
+ // get invalidated when processing the successors.
+ unsigned BBDFSNum = BBInfo.DFSNum;
+
// If we are done with this block, remove it from the worklist.
if (NextSucc == GraphT::child_end(BB)) {
Worklist.pop_back();
@@ -93,7 +105,7 @@
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &SuccVInfo =
DT.Info[Succ];
if (SuccVInfo.Semi == 0) {
- SuccVInfo.Parent = BB;
+ SuccVInfo.Parent = BBDFSNum;
Worklist.push_back(std::make_pair(Succ, GraphT::child_begin(Succ)));
}
}
@@ -106,9 +118,8 @@
typename GraphT::NodeType *VIn) {
std::vector<typename GraphT::NodeType*> Work;
SmallPtrSet<typename GraphT::NodeType*, 32> Visited;
- typename GraphT::NodeType* VInAncestor = DT.Info[VIn].Ancestor;
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VInVAInfo =
- DT.Info[VInAncestor];
+ DT.Info[DT.Vertex[DT.Info[VIn].Ancestor]];
if (VInVAInfo.Ancestor != 0)
Work.push_back(VIn);
@@ -117,7 +128,7 @@
typename GraphT::NodeType* V = Work.back();
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VInfo =
DT.Info[V];
- typename GraphT::NodeType* VAncestor = VInfo.Ancestor;
+ typename GraphT::NodeType* VAncestor = DT.Vertex[VInfo.Ancestor];
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VAInfo =
DT.Info[VAncestor];
@@ -168,11 +179,11 @@
template<class GraphT>
void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType* V, typename GraphT::NodeType* W,
+ unsigned DFSNumV, typename GraphT::NodeType* W,
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo) {
#if !BALANCE_IDOM_TREE
// Higher-complexity but faster implementation
- WInfo.Ancestor = V;
+ WInfo.Ancestor = DFSNumV;
#else
// Lower-complexity but slower implementation
GraphT::NodeType* WLabel = WInfo.Label;
@@ -220,10 +231,30 @@
void Calculate(DominatorTreeBase<typename GraphTraits<NodeT>::NodeType>& DT,
FuncT& F) {
typedef GraphTraits<NodeT> GraphT;
-
+
+ unsigned N = 0;
+
+ // Add a node for the root. This node might be the actual root, if there is
+ // one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0)
+ // which postdominates all real exits if there are multiple exit blocks.
+ typename GraphT::NodeType* Root = DT.Roots.size() == 1 ? DT.Roots[0]
+ : 0;
+ bool MultipleRoots = (DT.Roots.size() > 1);
+
+ if (MultipleRoots) {
+ typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
+ DT.Info[NULL];
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
+ BBInfo.Label = NULL;
+
+ DT.Vertex.push_back(NULL); // Vertex[n] = V;
+ //BBInfo[V].Ancestor = 0; // Ancestor[n] = 0
+ //BBInfo[V].Child = 0; // Child[v] = 0
+ BBInfo.Size = 1; // Size[v] = 1
+ }
+
// Step #1: Number blocks in depth-first order and initialize variables used
// in later stages of the algorithm.
- unsigned N = 0;
for (unsigned i = 0, e = DT.Roots.size(); i != e; ++i)
N = DFSPass<GraphT>(DT, DT.Roots[i], N);
@@ -233,19 +264,34 @@
DT.Info[W];
// Step #2: Calculate the semidominators of all vertices
+ bool HasChildOutsideDFS = false;
+
+ // initialize the semi dominator to point to the parent node
+ WInfo.Semi = WInfo.Parent;
for (typename GraphTraits<Inverse<NodeT> >::ChildIteratorType CI =
GraphTraits<Inverse<NodeT> >::child_begin(W),
- E = GraphTraits<Inverse<NodeT> >::child_end(W); CI != E; ++CI)
+ E = GraphTraits<Inverse<NodeT> >::child_end(W); CI != E; ++CI) {
if (DT.Info.count(*CI)) { // Only if this predecessor is reachable!
unsigned SemiU = DT.Info[Eval<GraphT>(DT, *CI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
+ else {
+ // if the child has no DFS number it is not post-dominated by any exit,
+ // and so is the current block.
+ HasChildOutsideDFS = true;
+ }
+ }
+
+ // if some child has no DFS number it is not post-dominated by any exit,
+ // and so is the current block.
+ if (DT.isPostDominator() && HasChildOutsideDFS)
+ WInfo.Semi = 0;
DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
- typename GraphT::NodeType* WParent = WInfo.Parent;
- Link<GraphT>(DT, WParent, W, WInfo);
+ typename GraphT::NodeType* WParent = DT.Vertex[WInfo.Parent];
+ Link<GraphT>(DT, WInfo.Parent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<typename GraphT::NodeType*> &WParentBucket =
@@ -271,29 +317,39 @@
// Add a node for the root. This node might be the actual root, if there is
// one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0)
// which postdominates all real exits if there are multiple exit blocks.
- typename GraphT::NodeType* Root = DT.Roots.size() == 1 ? DT.Roots[0]
- : 0;
DT.DomTreeNodes[Root] = DT.RootNode =
new DomTreeNodeBase<typename GraphT::NodeType>(Root, 0);
// Loop over all of the reachable blocks in the function...
- for (typename FuncT::iterator I = F.begin(), E = F.end(); I != E; ++I)
- if (typename GraphT::NodeType* ImmDom = DT.getIDom(I)) {
- // Reachable block.
- DomTreeNodeBase<typename GraphT::NodeType> *BBNode = DT.DomTreeNodes[I];
- if (BBNode) continue; // Haven't calculated this node yet?
+ for (unsigned i = 2; i <= N; ++i) {
+ typename GraphT::NodeType* W = DT.Vertex[i];
- // Get or calculate the node for the immediate dominator
- DomTreeNodeBase<typename GraphT::NodeType> *IDomNode =
+ DomTreeNodeBase<typename GraphT::NodeType> *BBNode = DT.DomTreeNodes[W];
+ if (BBNode) continue; // Haven't calculated this node yet?
+
+ typename GraphT::NodeType* ImmDom = DT.getIDom(W);
+
+ // skip all non root nodes that have no dominator - this occures with
+ // infinite loops.
+ if (!ImmDom && std::count(DT.Roots.begin(), DT.Roots.end(), W) == 0)
+ continue;
+
+ // Get or calculate the node for the immediate dominator
+ DomTreeNodeBase<typename GraphT::NodeType> *IDomNode =
DT.getNodeForBlock(ImmDom);
- // Add a new tree node for this BasicBlock, and link it as a child of
- // IDomNode
- DomTreeNodeBase<typename GraphT::NodeType> *C =
- new DomTreeNodeBase<typename GraphT::NodeType>(I, IDomNode);
- DT.DomTreeNodes[I] = IDomNode->addChild(C);
- }
-
+ // skip all children that are dominated by a non root node that, by itself,
+ // has no dominator.
+ if (!IDomNode)
+ continue;
+
+ // Add a new tree node for this BasicBlock, and link it as a child of
+ // IDomNode
+ DomTreeNodeBase<typename GraphT::NodeType> *C =
+ new DomTreeNodeBase<typename GraphT::NodeType>(W, IDomNode);
+ DT.DomTreeNodes[W] = IDomNode->addChild(C);
+ }
+
// Free temporary memory used to construct idom's
DT.IDoms.clear();
DT.Info.clear();
Modified: llvm/trunk/include/llvm/Analysis/Dominators.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/Dominators.h?rev=49768&r1=49767&r2=49768&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/Dominators.h (original)
+++ llvm/trunk/include/llvm/Analysis/Dominators.h Tue Apr 15 23:21:16 2008
@@ -182,13 +182,16 @@
unsigned int SlowQueries;
// Information record used during immediate dominators computation.
struct InfoRec {
+ unsigned DFSNum;
unsigned Semi;
unsigned Size;
- NodeT *Label, *Parent, *Child, *Ancestor;
+ NodeT *Label, *Child;
+ unsigned Parent, Ancestor;
std::vector<NodeT*> Bucket;
- InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0) {}
+ InfoRec() : DFSNum(0), Semi(0), Size(0), Label(0), Child(0), Parent(0),
+ Ancestor(0) {}
};
DenseMap<NodeT*, NodeT*> IDoms;
@@ -544,8 +547,7 @@
template<class GraphT>
friend void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType* V,
- typename GraphT::NodeType* W,
+ unsigned DFSNumV, typename GraphT::NodeType* W,
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo);
template<class GraphT>
@@ -602,8 +604,18 @@
// Haven't calculated this node yet? Get or calculate the node for the
// immediate dominator.
NodeT *IDom = getIDom(BB);
+
+ // skip all non root nodes that have no dominator
+ if (!IDom && std::count(this->Roots.begin(), this->Roots.end(), BB) == 0)
+ return NULL;
+
DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
+ // skip all nodes that are dominated by a non root node that, by itself,
+ // has no dominator.
+ if (!IDomNode)
+ return NULL;
+
// Add a new tree node for this BasicBlock, and link it as a child of
// IDomNode
DomTreeNodeBase<NodeT> *C = new DomTreeNodeBase<NodeT>(BB, IDomNode);
@@ -616,9 +628,7 @@
}
inline void addRoot(NodeT* BB) {
- // Unreachable block is not a root node.
- if (!isa<UnreachableInst>(&BB->back()))
- this->Roots.push_back(BB);
+ this->Roots.push_back(BB);
}
public:
Modified: llvm/trunk/lib/Analysis/PostDominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/PostDominators.cpp?rev=49768&r1=49767&r2=49768&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/PostDominators.cpp (original)
+++ llvm/trunk/lib/Analysis/PostDominators.cpp Tue Apr 15 23:21:16 2008
@@ -11,9 +11,12 @@
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "postdomtree"
+
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Instructions.h"
#include "llvm/Support/CFG.h"
+#include "llvm/Support/Debug.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/Analysis/DominatorInternals.h"
@@ -30,6 +33,7 @@
bool PostDominatorTree::runOnFunction(Function &F) {
DT->recalculate(F);
+ DEBUG(DT->dump());
return false;
}
Modified: llvm/trunk/lib/VMCore/Dominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Dominators.cpp?rev=49768&r1=49767&r2=49768&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/Dominators.cpp (original)
+++ llvm/trunk/lib/VMCore/Dominators.cpp Tue Apr 15 23:21:16 2008
@@ -14,9 +14,12 @@
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "domtree"
+
#include "llvm/Analysis/Dominators.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SmallPtrSet.h"
@@ -58,7 +61,7 @@
bool DominatorTree::runOnFunction(Function &F) {
DT->recalculate(F);
-
+ DEBUG(DT->dump());
return false;
}
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