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//===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a '-print-cfg' analysis pass, which emits the
// cfg.<fnname>.dot file for each function in the program, with a graph of the
// CFG for that function.
//
// The other main feature of this file is that it implements the
// Function::viewCFG method, which is useful for debugging passes which operate
// on the CFG.
//
//===----------------------------------------------------------------------===//
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/CFGPrinter.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Config/config.h"
#include <iosfwd>
#include <sstream>
#include <fstream>
using namespace llvm;
/// CFGOnly flag - This is used to control whether or not the CFG graph printer
/// prints out the contents of basic blocks or not. This is acceptable because
/// this code is only really used for debugging purposes.
///
static bool CFGOnly = false;
namespace llvm {
template<>
struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
static std::string getGraphName(const Function *F) {
return "CFG for '" + F->getName() + "' function";
}
static std::string getNodeLabel(const BasicBlock *Node,
const Function *Graph) {
if (CFGOnly && !Node->getName().empty())
return Node->getName() + ":";
std::ostringstream Out;
if (CFGOnly) {
WriteAsOperand(Out, Node, false);
return Out.str();
}
if (Node->getName().empty()) {
WriteAsOperand(Out, Node, false);
Out << ":";
}
Out << *Node;
std::string OutStr = Out.str();
if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
// Process string output to make it nicer...
for (unsigned i = 0; i != OutStr.length(); ++i)
if (OutStr[i] == '\n') { // Left justify
OutStr[i] = '\\';
OutStr.insert(OutStr.begin()+i+1, 'l');
} else if (OutStr[i] == ';') { // Delete comments!
unsigned Idx = OutStr.find('\n', i+1); // Find end of line
OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
--i;
}
return OutStr;
}
static std::string getEdgeSourceLabel(const BasicBlock *Node,
succ_const_iterator I) {
// Label source of conditional branches with "T" or "F"
if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
if (BI->isConditional())
return (I == succ_begin(Node)) ? "T" : "F";
return "";
}
};
}
namespace {
struct VISIBILITY_HIDDEN CFGViewer : public FunctionPass {
static char ID; // Pass identifcation, replacement for typeid
CFGViewer() : FunctionPass((intptr_t)&ID) {}
virtual bool runOnFunction(Function &F) {
F.viewCFG();
return false;
}
void print(std::ostream &OS, const Module* = 0) const {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
char CFGViewer::ID = 0;
RegisterPass<CFGViewer> V0("view-cfg",
"View CFG of function", false, true);
struct VISIBILITY_HIDDEN CFGOnlyViewer : public FunctionPass {
static char ID; // Pass identifcation, replacement for typeid
CFGOnlyViewer() : FunctionPass((intptr_t)&ID) {}
virtual bool runOnFunction(Function &F) {
CFGOnly = true;
F.viewCFG();
CFGOnly = false;
return false;
}
void print(std::ostream &OS, const Module* = 0) const {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
char CFGOnlyViewer::ID = 0;
RegisterPass<CFGOnlyViewer> V1("view-cfg-only",
"View CFG of function (with no function bodies)", false, true);
struct VISIBILITY_HIDDEN CFGPrinter : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
CFGPrinter() : FunctionPass((intptr_t)&ID) {}
explicit CFGPrinter(intptr_t pid) : FunctionPass(pid) {}
virtual bool runOnFunction(Function &F) {
std::string Filename = "cfg." + F.getName() + ".dot";
cerr << "Writing '" << Filename << "'...";
std::ofstream File(Filename.c_str());
if (File.good())
WriteGraph(File, (const Function*)&F);
else
cerr << " error opening file for writing!";
cerr << "\n";
return false;
}
void print(std::ostream &OS, const Module* = 0) const {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
char CFGPrinter::ID = 0;
RegisterPass<CFGPrinter> P1("print-cfg",
"Print CFG of function to 'dot' file", false, true);
struct VISIBILITY_HIDDEN CFGOnlyPrinter : public CFGPrinter {
static char ID; // Pass identification, replacement for typeid
CFGOnlyPrinter() : CFGPrinter((intptr_t)&ID) {}
virtual bool runOnFunction(Function &F) {
bool OldCFGOnly = CFGOnly;
CFGOnly = true;
CFGPrinter::runOnFunction(F);
CFGOnly = OldCFGOnly;
return false;
}
void print(std::ostream &OS, const Module* = 0) const {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
};
char CFGOnlyPrinter::ID = 0;
RegisterPass<CFGOnlyPrinter>
P2("print-cfg-only",
"Print CFG of function to 'dot' file (with no function bodies)", false, true);
}
/// viewCFG - This function is meant for use from the debugger. You can just
/// say 'call F->viewCFG()' and a ghostview window should pop up from the
/// program, displaying the CFG of the current function. This depends on there
/// being a 'dot' and 'gv' program in your path.
///
void Function::viewCFG() const {
ViewGraph(this, "cfg" + getName());
}
/// viewCFGOnly - This function is meant for use from the debugger. It works
/// just like viewCFG, but it does not include the contents of basic blocks
/// into the nodes, just the label. If you are only interested in the CFG t
/// his can make the graph smaller.
///
void Function::viewCFGOnly() const {
CFGOnly = true;
viewCFG();
CFGOnly = false;
}
FunctionPass *llvm::createCFGPrinterPass () {
return new CFGPrinter();
}
FunctionPass *llvm::createCFGOnlyPrinterPass () {
return new CFGOnlyPrinter();
}
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