blob: 65e3184fad91a3645feb568af01334eb9689d0e2 [file] [log] [blame]
//===- CallPrinter.cpp - DOT printer for call 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 '-dot-callgraph', which emit a callgraph.<fnname>.dot
// containing the call graph of a module.
//
// There is also a pass available to directly call dotty ('-view-callgraph').
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CallPrinter.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/HeatUtils.h"
#include "llvm/IR/Instructions.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DOTGraphTraits.h"
#include "llvm/Support/GraphWriter.h"
using namespace llvm;
namespace llvm {
template <class GraphType> struct GraphTraits;
}
// This option shows static (relative) call counts.
// FIXME:
// Need to show real counts when profile data is available
static cl::opt<bool> ShowHeatColors("callgraph-heat-colors", cl::init(false),
cl::Hidden,
cl::desc("Show heat colors in call-graph"));
static cl::opt<bool>
ShowEdgeWeight("callgraph-show-weights", cl::init(false), cl::Hidden,
cl::desc("Show edges labeled with weights"));
static cl::opt<bool>
CallMultiGraph("callgraph-multigraph", cl::init(false), cl::Hidden,
cl::desc("Show call-multigraph (do not remove parallel edges)"));
static cl::opt<std::string> CallGraphDotFilenamePrefix(
"callgraph-dot-filename-prefix", cl::Hidden,
cl::desc("The prefix used for the CallGraph dot file names."));
namespace llvm {
class CallGraphDOTInfo {
private:
Module *M;
CallGraph *CG;
DenseMap<const Function *, uint64_t> Freq;
uint64_t MaxFreq;
public:
std::function<BlockFrequencyInfo *(Function &)> LookupBFI;
CallGraphDOTInfo(Module *M, CallGraph *CG,
function_ref<BlockFrequencyInfo *(Function &)> LookupBFI)
: M(M), CG(CG), LookupBFI(LookupBFI) {
MaxFreq = 0;
for (Function &F : M->getFunctionList()) {
uint64_t localSumFreq = 0;
SmallSet<Function *, 16> Callers;
for (User *U : F.users())
if (isa<CallInst>(U))
Callers.insert(cast<Instruction>(U)->getFunction());
for (Function *Caller : Callers)
localSumFreq += getNumOfCalls(*Caller, F);
if (localSumFreq >= MaxFreq)
MaxFreq = localSumFreq;
Freq[&F] = localSumFreq;
}
if (!CallMultiGraph)
removeParallelEdges();
}
Module *getModule() const { return M; }
CallGraph *getCallGraph() const { return CG; }
uint64_t getFreq(const Function *F) { return Freq[F]; }
uint64_t getMaxFreq() { return MaxFreq; }
private:
void removeParallelEdges() {
for (auto &I : (*CG)) {
CallGraphNode *Node = I.second.get();
bool FoundParallelEdge = true;
while (FoundParallelEdge) {
SmallSet<Function *, 16> Visited;
FoundParallelEdge = false;
for (auto CI = Node->begin(), CE = Node->end(); CI != CE; CI++) {
if (!(Visited.insert(CI->second->getFunction())).second) {
FoundParallelEdge = true;
Node->removeCallEdge(CI);
break;
}
}
}
}
}
};
template <>
struct GraphTraits<CallGraphDOTInfo *>
: public GraphTraits<const CallGraphNode *> {
static NodeRef getEntryNode(CallGraphDOTInfo *CGInfo) {
// Start at the external node!
return CGInfo->getCallGraph()->getExternalCallingNode();
}
typedef std::pair<const Function *const, std::unique_ptr<CallGraphNode>>
PairTy;
static const CallGraphNode *CGGetValuePtr(const PairTy &P) {
return P.second.get();
}
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
typedef mapped_iterator<CallGraph::const_iterator, decltype(&CGGetValuePtr)>
nodes_iterator;
static nodes_iterator nodes_begin(CallGraphDOTInfo *CGInfo) {
return nodes_iterator(CGInfo->getCallGraph()->begin(), &CGGetValuePtr);
}
static nodes_iterator nodes_end(CallGraphDOTInfo *CGInfo) {
return nodes_iterator(CGInfo->getCallGraph()->end(), &CGGetValuePtr);
}
};
template <>
struct DOTGraphTraits<CallGraphDOTInfo *> : public DefaultDOTGraphTraits {
DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(CallGraphDOTInfo *CGInfo) {
return "Call graph: " +
std::string(CGInfo->getModule()->getModuleIdentifier());
}
static bool isNodeHidden(const CallGraphNode *Node,
const CallGraphDOTInfo *CGInfo) {
if (CallMultiGraph || Node->getFunction())
return false;
return true;
}
std::string getNodeLabel(const CallGraphNode *Node,
CallGraphDOTInfo *CGInfo) {
if (Node == CGInfo->getCallGraph()->getExternalCallingNode())
return "external caller";
if (Node == CGInfo->getCallGraph()->getCallsExternalNode())
return "external callee";
if (Function *Func = Node->getFunction())
return std::string(Func->getName());
return "external node";
}
static const CallGraphNode *CGGetValuePtr(CallGraphNode::CallRecord P) {
return P.second;
}
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
typedef mapped_iterator<CallGraphNode::const_iterator,
decltype(&CGGetValuePtr)>
nodes_iterator;
std::string getEdgeAttributes(const CallGraphNode *Node, nodes_iterator I,
CallGraphDOTInfo *CGInfo) {
if (!ShowEdgeWeight)
return "";
Function *Caller = Node->getFunction();
if (Caller == nullptr || Caller->isDeclaration())
return "";
Function *Callee = (*I)->getFunction();
if (Callee == nullptr)
return "";
uint64_t Counter = getNumOfCalls(*Caller, *Callee);
double Width =
1 + 2 * (double(Counter) / CGInfo->getMaxFreq());
std::string Attrs = "label=\"" + std::to_string(Counter) +
"\" penwidth=" + std::to_string(Width);
return Attrs;
}
std::string getNodeAttributes(const CallGraphNode *Node,
CallGraphDOTInfo *CGInfo) {
Function *F = Node->getFunction();
if (F == nullptr)
return "";
std::string attrs;
if (ShowHeatColors) {
uint64_t freq = CGInfo->getFreq(F);
std::string color = getHeatColor(freq, CGInfo->getMaxFreq());
std::string edgeColor = (freq <= (CGInfo->getMaxFreq() / 2))
? getHeatColor(0)
: getHeatColor(1);
attrs = "color=\"" + edgeColor + "ff\", style=filled, fillcolor=\"" +
color + "80\"";
}
return attrs;
}
};
} // end llvm namespace
namespace {
void doCallGraphDOTPrinting(
Module &M, function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
std::string Filename;
if (!CallGraphDotFilenamePrefix.empty())
Filename = (CallGraphDotFilenamePrefix + ".callgraph.dot");
else
Filename = (std::string(M.getModuleIdentifier()) + ".callgraph.dot");
errs() << "Writing '" << Filename << "'...";
std::error_code EC;
raw_fd_ostream File(Filename, EC, sys::fs::OF_Text);
CallGraph CG(M);
CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI);
if (!EC)
WriteGraph(File, &CFGInfo);
else
errs() << " error opening file for writing!";
errs() << "\n";
}
void viewCallGraph(Module &M,
function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
CallGraph CG(M);
CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI);
std::string Title =
DOTGraphTraits<CallGraphDOTInfo *>::getGraphName(&CFGInfo);
ViewGraph(&CFGInfo, "callgraph", true, Title);
}
} // namespace
namespace llvm {
PreservedAnalyses CallGraphDOTPrinterPass::run(Module &M,
ModuleAnalysisManager &AM) {
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
auto LookupBFI = [&FAM](Function &F) {
return &FAM.getResult<BlockFrequencyAnalysis>(F);
};
doCallGraphDOTPrinting(M, LookupBFI);
return PreservedAnalyses::all();
}
PreservedAnalyses CallGraphViewerPass::run(Module &M,
ModuleAnalysisManager &AM) {
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
auto LookupBFI = [&FAM](Function &F) {
return &FAM.getResult<BlockFrequencyAnalysis>(F);
};
viewCallGraph(M, LookupBFI);
return PreservedAnalyses::all();
}
} // namespace llvm
namespace {
// Viewer
class CallGraphViewer : public ModulePass {
public:
static char ID;
CallGraphViewer() : ModulePass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnModule(Module &M) override;
};
void CallGraphViewer::getAnalysisUsage(AnalysisUsage &AU) const {
ModulePass::getAnalysisUsage(AU);
AU.addRequired<BlockFrequencyInfoWrapperPass>();
AU.setPreservesAll();
}
bool CallGraphViewer::runOnModule(Module &M) {
auto LookupBFI = [this](Function &F) {
return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
};
viewCallGraph(M, LookupBFI);
return false;
}
// DOT Printer
class CallGraphDOTPrinter : public ModulePass {
public:
static char ID;
CallGraphDOTPrinter() : ModulePass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnModule(Module &M) override;
};
void CallGraphDOTPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
ModulePass::getAnalysisUsage(AU);
AU.addRequired<BlockFrequencyInfoWrapperPass>();
AU.setPreservesAll();
}
bool CallGraphDOTPrinter::runOnModule(Module &M) {
auto LookupBFI = [this](Function &F) {
return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
};
doCallGraphDOTPrinting(M, LookupBFI);
return false;
}
} // end anonymous namespace
char CallGraphViewer::ID = 0;
INITIALIZE_PASS(CallGraphViewer, "view-callgraph", "View call graph", false,
false)
char CallGraphDOTPrinter::ID = 0;
INITIALIZE_PASS(CallGraphDOTPrinter, "dot-callgraph",
"Print call graph to 'dot' file", false, false)
// Create methods available outside of this file, to use them
// "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by
// the link time optimization.
ModulePass *llvm::createCallGraphViewerPass() { return new CallGraphViewer(); }
ModulePass *llvm::createCallGraphDOTPrinterPass() {
return new CallGraphDOTPrinter();
}