llvm/tools/opt/PrintSCC.cpp
Chandler Carruth 54fec07ec0 [PM] Split the CallGraph out from the ModulePass which creates the
CallGraph.

This makes the CallGraph a totally generic analysis object that is the
container for the graph data structure and the primary interface for
querying and manipulating it. The pass logic is separated into its own
class. For compatibility reasons, the pass provides wrapper methods for
most of the methods on CallGraph -- they all just forward.

This will allow the new pass manager infrastructure to provide its own
analysis pass that constructs the same CallGraph object and makes it
available. The idea is that in the new pass manager, the analysis pass's
'run' method returns a concrete analysis 'result'. Here, that result is
a 'CallGraph'. The 'run' method will typically do only minimal work,
deferring much of the work into the implementation of the result object
in order to be lazy about computing things, but when (like DomTree)
there is *some* up-front computation, the analysis does it prior to
handing the result back to the querying pass.

I know some of this is fairly ugly. I'm happy to change it around if
folks can suggest a cleaner interim state, but there is going to be some
amount of unavoidable ugliness during the transition period. The good
thing is that this is very limited and will naturally go away when the
old pass infrastructure goes away. It won't hang around to bother us
later.

Next up is the initial new-PM-style call graph analysis. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195722 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-26 04:19:30 +00:00

113 lines
3.9 KiB
C++

//===- PrintSCC.cpp - Enumerate SCCs in some key graphs -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides passes to print out SCCs in a CFG or a CallGraph.
// Normally, you would not use these passes; instead, you would use the
// scc_iterator directly to enumerate SCCs and process them in some way. These
// passes serve three purposes:
//
// (1) As a reference for how to use the scc_iterator.
// (2) To print out the SCCs for a CFG or a CallGraph:
// analyze -print-cfg-sccs to print the SCCs in each CFG of a module.
// analyze -print-cfg-sccs -stats to print the #SCCs and the maximum SCC size.
// analyze -print-cfg-sccs -debug > /dev/null to watch the algorithm in action.
//
// and similarly:
// analyze -print-callgraph-sccs [-stats] [-debug] to print SCCs in the CallGraph
//
// (3) To test the scc_iterator.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SCCIterator.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
struct CFGSCC : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
CFGSCC() : FunctionPass(ID) {}
bool runOnFunction(Function& func);
void print(raw_ostream &O, const Module* = 0) const { }
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
struct CallGraphSCC : public ModulePass {
static char ID; // Pass identification, replacement for typeid
CallGraphSCC() : ModulePass(ID) {}
// run - Print out SCCs in the call graph for the specified module.
bool runOnModule(Module &M);
void print(raw_ostream &O, const Module* = 0) const { }
// getAnalysisUsage - This pass requires the CallGraph.
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<CallGraphWrapperPass>();
}
};
}
char CFGSCC::ID = 0;
static RegisterPass<CFGSCC>
Y("print-cfg-sccs", "Print SCCs of each function CFG");
char CallGraphSCC::ID = 0;
static RegisterPass<CallGraphSCC>
Z("print-callgraph-sccs", "Print SCCs of the Call Graph");
bool CFGSCC::runOnFunction(Function &F) {
unsigned sccNum = 0;
errs() << "SCCs for Function " << F.getName() << " in PostOrder:";
for (scc_iterator<Function*> SCCI = scc_begin(&F),
E = scc_end(&F); SCCI != E; ++SCCI) {
std::vector<BasicBlock*> &nextSCC = *SCCI;
errs() << "\nSCC #" << ++sccNum << " : ";
for (std::vector<BasicBlock*>::const_iterator I = nextSCC.begin(),
E = nextSCC.end(); I != E; ++I)
errs() << (*I)->getName() << ", ";
if (nextSCC.size() == 1 && SCCI.hasLoop())
errs() << " (Has self-loop).";
}
errs() << "\n";
return true;
}
// run - Print out SCCs in the call graph for the specified module.
bool CallGraphSCC::runOnModule(Module &M) {
CallGraphNode *rootNode = getAnalysis<CallGraphWrapperPass>().getRoot();
unsigned sccNum = 0;
errs() << "SCCs for the program in PostOrder:";
for (scc_iterator<CallGraphNode*> SCCI = scc_begin(rootNode),
E = scc_end(rootNode); SCCI != E; ++SCCI) {
const std::vector<CallGraphNode*> &nextSCC = *SCCI;
errs() << "\nSCC #" << ++sccNum << " : ";
for (std::vector<CallGraphNode*>::const_iterator I = nextSCC.begin(),
E = nextSCC.end(); I != E; ++I)
errs() << ((*I)->getFunction() ? (*I)->getFunction()->getName()
: "external node") << ", ";
if (nextSCC.size() == 1 && SCCI.hasLoop())
errs() << " (Has self-loop).";
}
errs() << "\n";
return true;
}