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//===- DDGPrinter.cpp - DOT printer for the data dependence graph ----------==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//
// This file defines the `-dot-ddg` analysis pass, which emits DDG in DOT format
// in a file named `ddg.<graph-name>.dot` for each loop in a function.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DDGPrinter.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/GraphWriter.h"
using namespace llvm;
static cl::opt<bool> DotOnly("dot-ddg-only", cl::init(false), cl::Hidden,
cl::ZeroOrMore, cl::desc("simple ddg dot graph"));
static cl::opt<std::string> DDGDotFilenamePrefix(
"dot-ddg-filename-prefix", cl::init("ddg"), cl::Hidden,
cl::desc("The prefix used for the DDG dot file names."));
static void writeDDGToDotFile(DataDependenceGraph &G, bool DOnly = false);
//===--------------------------------------------------------------------===//
// Implementation of DDG DOT Printer for a loop
//===--------------------------------------------------------------------===//
PreservedAnalyses DDGDotPrinterPass::run(Loop &L, LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR,
LPMUpdater &U) {
writeDDGToDotFile(*AM.getResult<DDGAnalysis>(L, AR), DotOnly);
return PreservedAnalyses::all();
}
static void writeDDGToDotFile(DataDependenceGraph &G, bool DOnly) {
std::string Filename =
Twine(DDGDotFilenamePrefix + "." + G.getName() + ".dot").str();
errs() << "Writing '" << Filename << "'...";
std::error_code EC;
raw_fd_ostream File(Filename, EC, sys::fs::OF_Text);
if (!EC)
// We only provide the constant verson of the DOTGraphTrait specialization,
// hence the conversion to const pointer
WriteGraph(File, (const DataDependenceGraph *)&G, DOnly);
else
errs() << " error opening file for writing!";
errs() << "\n";
}
//===--------------------------------------------------------------------===//
// DDG DOT Printer Implementation
//===--------------------------------------------------------------------===//
std::string DDGDotGraphTraits::getNodeLabel(const DDGNode *Node,
const DataDependenceGraph *Graph) {
if (isSimple())
return getSimpleNodeLabel(Node, Graph);
else
return getVerboseNodeLabel(Node, Graph);
}
std::string DDGDotGraphTraits::getEdgeAttributes(
const DDGNode *Node, GraphTraits<const DDGNode *>::ChildIteratorType I,
const DataDependenceGraph *G) {
const DDGEdge *E = static_cast<const DDGEdge *>(*I.getCurrent());
if (isSimple())
return getSimpleEdgeAttributes(Node, E, G);
else
return getVerboseEdgeAttributes(Node, E, G);
}
bool DDGDotGraphTraits::isNodeHidden(const DDGNode *Node,
const DataDependenceGraph *Graph) {
if (isSimple() && isa<RootDDGNode>(Node))
return true;
assert(Graph && "expected a valid graph pointer");
return Graph->getPiBlock(*Node) != nullptr;
}
std::string
DDGDotGraphTraits::getSimpleNodeLabel(const DDGNode *Node,
const DataDependenceGraph *G) {
std::string Str;
raw_string_ostream OS(Str);
if (isa<SimpleDDGNode>(Node))
for (auto *II : static_cast<const SimpleDDGNode *>(Node)->getInstructions())
OS << *II << "\n";
else if (isa<PiBlockDDGNode>(Node))
OS << "pi-block\nwith\n"
<< cast<PiBlockDDGNode>(Node)->getNodes().size() << " nodes\n";
else if (isa<RootDDGNode>(Node))
OS << "root\n";
else
llvm_unreachable("Unimplemented type of node");
return OS.str();
}
std::string
DDGDotGraphTraits::getVerboseNodeLabel(const DDGNode *Node,
const DataDependenceGraph *G) {
std::string Str;
raw_string_ostream OS(Str);
OS << "<kind:" << Node->getKind() << ">\n";
if (isa<SimpleDDGNode>(Node))
for (auto *II : static_cast<const SimpleDDGNode *>(Node)->getInstructions())
OS << *II << "\n";
else if (isa<PiBlockDDGNode>(Node)) {
OS << "--- start of nodes in pi-block ---\n";
unsigned Count = 0;
const auto &PNodes = cast<PiBlockDDGNode>(Node)->getNodes();
for (auto *PN : PNodes) {
OS << getVerboseNodeLabel(PN, G);
if (++Count != PNodes.size())
OS << "\n";
}
OS << "--- end of nodes in pi-block ---\n";
} else if (isa<RootDDGNode>(Node))
OS << "root\n";
else
llvm_unreachable("Unimplemented type of node");
return OS.str();
}
std::string DDGDotGraphTraits::getSimpleEdgeAttributes(
const DDGNode *Src, const DDGEdge *Edge, const DataDependenceGraph *G) {
std::string Str;
raw_string_ostream OS(Str);
DDGEdge::EdgeKind Kind = Edge->getKind();
OS << "label=\"[" << Kind << "]\"";
return OS.str();
}
std::string DDGDotGraphTraits::getVerboseEdgeAttributes(
const DDGNode *Src, const DDGEdge *Edge, const DataDependenceGraph *G) {
std::string Str;
raw_string_ostream OS(Str);
DDGEdge::EdgeKind Kind = Edge->getKind();
OS << "label=\"[";
if (Kind == DDGEdge::EdgeKind::MemoryDependence)
OS << G->getDependenceString(*Src, Edge->getTargetNode());
else
OS << Kind;
OS << "]\"";
return OS.str();
}