//===- RegionPrinter.cpp - Print regions tree pass ------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Print out the region tree of a function using dotty/graphviz.
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/RegionPrinter.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/DOTGraphTraitsPass.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

//===----------------------------------------------------------------------===//
/// onlySimpleRegion - Show only the simple regions in the RegionViewer.
static cl::opt<bool> onlySimpleRegions(
    "only-simple-regions",
    cl::desc("Show only simple regions in the graphviz viewer"), cl::Hidden,
    cl::init(false));

namespace llvm {
template <> struct DOTGraphTraits<RegionNode *> : public DefaultDOTGraphTraits {

  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}

  std::string getNodeLabel(RegionNode *Node, RegionNode *Graph) {

    if (!Node->isSubRegion()) {
      BasicBlock *BB = Node->getNodeAs<BasicBlock>();

      if (isSimple())
        return DOTGraphTraits<const Function *>::getSimpleNodeLabel(
            BB, BB->getParent());
      else
        return DOTGraphTraits<const Function *>::getCompleteNodeLabel(
            BB, BB->getParent());
    }

    return "Not implemented";
  }
};

template <>
struct DOTGraphTraits<RegionInfoPass *> : public DOTGraphTraits<RegionNode *> {

  DOTGraphTraits(bool isSimple = false)
      : DOTGraphTraits<RegionNode *>(isSimple) {}

  static std::string getGraphName(RegionInfoPass *DT) { return "Region Graph"; }

  std::string getNodeLabel(RegionNode *Node, RegionInfoPass *G) {
    RegionInfo &RI = G->getRegionInfo();
    return DOTGraphTraits<RegionNode *>::getNodeLabel(
        Node, reinterpret_cast<RegionNode *>(RI.getTopLevelRegion()));
  }

  std::string getEdgeAttributes(RegionNode *srcNode,
                                GraphTraits<RegionInfo *>::ChildIteratorType CI,
                                RegionInfoPass *G) {
    RegionInfo &RI = G->getRegionInfo();
    RegionNode *destNode = *CI;

    if (srcNode->isSubRegion() || destNode->isSubRegion())
      return "";

    // In case of a backedge, do not use it to define the layout of the nodes.
    BasicBlock *srcBB = srcNode->getNodeAs<BasicBlock>();
    BasicBlock *destBB = destNode->getNodeAs<BasicBlock>();

    Region *R = RI.getRegionFor(destBB);

    while (R && R->getParent())
      if (R->getParent()->getEntry() == destBB)
        R = R->getParent();
      else
        break;

    if (R && R->getEntry() == destBB &&
        R->contains(srcBB)) // HLSL Change - add null check
      return "constraint=false";

    return "";
  }

  // Print the cluster of the subregions. This groups the single basic blocks
  // and adds a different background color for each group.
  static void printRegionCluster(const Region &R,
                                 GraphWriter<RegionInfoPass *> &GW,
                                 unsigned depth = 0) {
    raw_ostream &O = GW.getOStream();
    O.indent(2 * depth) << "subgraph cluster_" << static_cast<const void *>(&R)
                        << " {\n";
    O.indent(2 * (depth + 1)) << "label = \"\";\n";

    if (!onlySimpleRegions || R.isSimple()) {
      O.indent(2 * (depth + 1)) << "style = filled;\n";
      O.indent(2 * (depth + 1))
          << "color = " << ((R.getDepth() * 2 % 12) + 1) << "\n";

    } else {
      O.indent(2 * (depth + 1)) << "style = solid;\n";
      O.indent(2 * (depth + 1))
          << "color = " << ((R.getDepth() * 2 % 12) + 2) << "\n";
    }

    for (Region::const_iterator RI = R.begin(), RE = R.end(); RI != RE; ++RI)
      printRegionCluster(**RI, GW, depth + 1);

    const RegionInfo &RI = *static_cast<const RegionInfo *>(R.getRegionInfo());

    for (auto *BB : R.blocks())
      if (RI.getRegionFor(BB) == &R)
        O.indent(2 * (depth + 1))
            << "Node"
            << static_cast<const void *>(RI.getTopLevelRegion()->getBBNode(BB))
            << ";\n";

    O.indent(2 * depth) << "}\n";
  }

  static void addCustomGraphFeatures(const RegionInfoPass *RIP,
                                     GraphWriter<RegionInfoPass *> &GW) {
    const RegionInfo &RI = RIP->getRegionInfo();
    raw_ostream &O = GW.getOStream();
    O << "\tcolorscheme = \"paired12\"\n";
    printRegionCluster(*RI.getTopLevelRegion(), GW, 4);
  }
};
} // end namespace llvm

namespace {

struct RegionViewer : public DOTGraphTraitsViewer<RegionInfoPass, false> {
  static char ID;
  RegionViewer() : DOTGraphTraitsViewer<RegionInfoPass, false>("reg", ID) {
    initializeRegionViewerPass(*PassRegistry::getPassRegistry());
  }
};
char RegionViewer::ID = 0;

struct RegionOnlyViewer : public DOTGraphTraitsViewer<RegionInfoPass, true> {
  static char ID;
  RegionOnlyViewer()
      : DOTGraphTraitsViewer<RegionInfoPass, true>("regonly", ID) {
    initializeRegionOnlyViewerPass(*PassRegistry::getPassRegistry());
  }
};
char RegionOnlyViewer::ID = 0;

struct RegionPrinter : public DOTGraphTraitsPrinter<RegionInfoPass, false> {
  static char ID;
  RegionPrinter() : DOTGraphTraitsPrinter<RegionInfoPass, false>("reg", ID) {
    initializeRegionPrinterPass(*PassRegistry::getPassRegistry());
  }
};
char RegionPrinter::ID = 0;
} // end anonymous namespace

INITIALIZE_PASS(RegionPrinter, "dot-regions",
                "Print regions of function to 'dot' file", true, true)

INITIALIZE_PASS(RegionViewer, "view-regions", "View regions of function", true,
                true)

INITIALIZE_PASS(RegionOnlyViewer, "view-regions-only",
                "View regions of function (with no function bodies)", true,
                true)

namespace {

struct RegionOnlyPrinter : public DOTGraphTraitsPrinter<RegionInfoPass, true> {
  static char ID;
  RegionOnlyPrinter() : DOTGraphTraitsPrinter<RegionInfoPass, true>("reg", ID) {
    initializeRegionOnlyPrinterPass(*PassRegistry::getPassRegistry());
  }
};

} // namespace

char RegionOnlyPrinter::ID = 0;
INITIALIZE_PASS(RegionOnlyPrinter, "dot-regions-only",
                "Print regions of function to 'dot' file "
                "(with no function bodies)",
                true, true)

FunctionPass *llvm::createRegionViewerPass() { return new RegionViewer(); }

FunctionPass *llvm::createRegionOnlyViewerPass() {
  return new RegionOnlyViewer();
}

FunctionPass *llvm::createRegionPrinterPass() { return new RegionPrinter(); }

FunctionPass *llvm::createRegionOnlyPrinterPass() {
  return new RegionOnlyPrinter();
}
