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-rw-r--r--include/llvm/Support/GenericDomTreeConstruction.h142
1 files changed, 68 insertions, 74 deletions
diff --git a/include/llvm/Support/GenericDomTreeConstruction.h b/include/llvm/Support/GenericDomTreeConstruction.h
index 54e55cc1a32e..c1d757f3ab6a 100644
--- a/include/llvm/Support/GenericDomTreeConstruction.h
+++ b/include/llvm/Support/GenericDomTreeConstruction.h
@@ -24,82 +24,77 @@
#ifndef LLVM_SUPPORT_GENERICDOMTREECONSTRUCTION_H
#define LLVM_SUPPORT_GENERICDOMTREECONSTRUCTION_H
+#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/GenericDomTree.h"
namespace llvm {
-template <class GraphT>
-unsigned DFSPass(DominatorTreeBaseByGraphTraits<GraphT> &DT,
- typename GraphT::NodeRef V, unsigned N) {
- // This is more understandable as a recursive algorithm, but we can't use the
- // recursive algorithm due to stack depth issues. Keep it here for
- // documentation purposes.
-#if 0
- InfoRec &VInfo = DT.Info[DT.Roots[i]];
- VInfo.DFSNum = VInfo.Semi = ++N;
- VInfo.Label = V;
-
- Vertex.push_back(V); // Vertex[n] = V;
-
- for (succ_iterator SI = succ_begin(V), E = succ_end(V); SI != E; ++SI) {
- InfoRec &SuccVInfo = DT.Info[*SI];
- if (SuccVInfo.Semi == 0) {
- SuccVInfo.Parent = V;
- N = DTDFSPass(DT, *SI, N);
- }
+// External storage for depth first iterator that reuses the info lookup map
+// domtree already has. We don't have a set, but a map instead, so we are
+// converting the one argument insert calls.
+template <class NodeRef, class InfoType> struct df_iterator_dom_storage {
+public:
+ typedef DenseMap<NodeRef, InfoType> BaseSet;
+ df_iterator_dom_storage(BaseSet &Storage) : Storage(Storage) {}
+
+ typedef typename BaseSet::iterator iterator;
+ std::pair<iterator, bool> insert(NodeRef N) {
+ return Storage.insert({N, InfoType()});
}
-#else
- bool IsChildOfArtificialExit = (N != 0);
+ void completed(NodeRef) {}
- SmallVector<
- std::pair<typename GraphT::NodeRef, typename GraphT::ChildIteratorType>,
- 32>
- Worklist;
- Worklist.push_back(std::make_pair(V, GraphT::child_begin(V)));
- while (!Worklist.empty()) {
- typename GraphT::NodeRef BB = Worklist.back().first;
- typename GraphT::ChildIteratorType NextSucc = Worklist.back().second;
+private:
+ BaseSet &Storage;
+};
+template <class GraphT>
+unsigned ReverseDFSPass(DominatorTreeBaseByGraphTraits<GraphT> &DT,
+ typename GraphT::NodeRef V, unsigned N) {
+ df_iterator_dom_storage<
+ typename GraphT::NodeRef,
+ typename DominatorTreeBaseByGraphTraits<GraphT>::InfoRec>
+ DFStorage(DT.Info);
+ bool IsChildOfArtificialExit = (N != 0);
+ for (auto I = idf_ext_begin(V, DFStorage), E = idf_ext_end(V, DFStorage);
+ I != E; ++I) {
+ typename GraphT::NodeRef BB = *I;
auto &BBInfo = DT.Info[BB];
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
+ BBInfo.Label = BB;
+ // Set the parent to the top of the visited stack. The stack includes us,
+ // and is 1 based, so we subtract to account for both of these.
+ if (I.getPathLength() > 1)
+ BBInfo.Parent = DT.Info[I.getPath(I.getPathLength() - 2)].DFSNum;
+ DT.Vertex.push_back(BB); // Vertex[n] = V;
- // First time we visited this BB?
- if (NextSucc == GraphT::child_begin(BB)) {
- BBInfo.DFSNum = BBInfo.Semi = ++N;
- BBInfo.Label = BB;
-
- DT.Vertex.push_back(BB); // Vertex[n] = V;
-
- if (IsChildOfArtificialExit)
- BBInfo.Parent = 1;
-
- IsChildOfArtificialExit = 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();
- continue;
- }
-
- // Increment the successor number for the next time we get to it.
- ++Worklist.back().second;
-
- // Visit the successor next, if it isn't already visited.
- typename GraphT::NodeRef Succ = *NextSucc;
+ if (IsChildOfArtificialExit)
+ BBInfo.Parent = 1;
- auto &SuccVInfo = DT.Info[Succ];
- if (SuccVInfo.Semi == 0) {
- SuccVInfo.Parent = BBDFSNum;
- Worklist.push_back(std::make_pair(Succ, GraphT::child_begin(Succ)));
- }
+ IsChildOfArtificialExit = false;
}
-#endif
- return N;
+ return N;
+}
+template <class GraphT>
+unsigned DFSPass(DominatorTreeBaseByGraphTraits<GraphT> &DT,
+ typename GraphT::NodeRef V, unsigned N) {
+ df_iterator_dom_storage<
+ typename GraphT::NodeRef,
+ typename DominatorTreeBaseByGraphTraits<GraphT>::InfoRec>
+ DFStorage(DT.Info);
+ for (auto I = df_ext_begin(V, DFStorage), E = df_ext_end(V, DFStorage);
+ I != E; ++I) {
+ typename GraphT::NodeRef BB = *I;
+ auto &BBInfo = DT.Info[BB];
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
+ BBInfo.Label = BB;
+ // Set the parent to the top of the visited stack. The stack includes us,
+ // and is 1 based, so we subtract to account for both of these.
+ if (I.getPathLength() > 1)
+ BBInfo.Parent = DT.Info[I.getPath(I.getPathLength() - 2)].DFSNum;
+ DT.Vertex.push_back(BB); // Vertex[n] = V;
+ }
+ return N;
}
template <class GraphT>
@@ -163,9 +158,13 @@ void Calculate(DominatorTreeBaseByGraphTraits<GraphTraits<NodeT>> &DT,
// Step #1: Number blocks in depth-first order and initialize variables used
// in later stages of the algorithm.
- for (unsigned i = 0, e = static_cast<unsigned>(DT.Roots.size());
- i != e; ++i)
- N = DFSPass<GraphT>(DT, DT.Roots[i], N);
+ if (DT.isPostDominator()){
+ for (unsigned i = 0, e = static_cast<unsigned>(DT.Roots.size());
+ i != e; ++i)
+ N = ReverseDFSPass<GraphT>(DT, DT.Roots[i], N);
+ } else {
+ N = DFSPass<GraphT>(DT, DT.Roots[0], N);
+ }
// it might be that some blocks did not get a DFS number (e.g., blocks of
// infinite loops). In these cases an artificial exit node is required.
@@ -201,17 +200,12 @@ void Calculate(DominatorTreeBaseByGraphTraits<GraphTraits<NodeT>> &DT,
// initialize the semi dominator to point to the parent node
WInfo.Semi = WInfo.Parent;
- typedef GraphTraits<Inverse<NodeT> > InvTraits;
- for (typename InvTraits::ChildIteratorType CI =
- InvTraits::child_begin(W),
- E = InvTraits::child_end(W); CI != E; ++CI) {
- typename InvTraits::NodeRef N = *CI;
- if (DT.Info.count(N)) { // Only if this predecessor is reachable!
+ for (const auto &N : inverse_children<NodeT>(W))
+ if (DT.Info.count(N)) { // Only if this predecessor is reachable!
unsigned SemiU = DT.Info[Eval<GraphT>(DT, N, i + 1)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
- }
// If V is a non-root vertex and sdom(V) = parent(V), then idom(V) is
// necessarily parent(V). In this case, set idom(V) here and avoid placing
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-12 17:02:39 +0000