//===- DbgInfoPrinter.cpp - Print debug info in a human readable form ------==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a pass that prints instructions, and associated debug
// info:
// 
//   - source/line/col information
//   - original variable name
//   - original type name
//
//===----------------------------------------------------------------------===//

#include "llvm/Pass.h"
#include "llvm/Function.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

static cl::opt<bool>
PrintDirectory("print-fullpath",
               cl::desc("Print fullpath when printing debug info"),
               cl::Hidden);

namespace {
  class PrintDbgInfo : public FunctionPass {
    raw_ostream &Out;
    void printStopPoint(const DbgStopPointInst *DSI);
    void printFuncStart(const DbgFuncStartInst *FS);
    void printVariableDeclaration(const Value *V);
  public:
    static char ID; // Pass identification
    PrintDbgInfo() : FunctionPass(&ID), Out(outs()) {}

    virtual bool runOnFunction(Function &F);
    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
      AU.setPreservesAll();
    }
  };
  char PrintDbgInfo::ID = 0;
  static RegisterPass<PrintDbgInfo> X("print-dbginfo",
                                     "Print debug info in human readable form");
}

FunctionPass *llvm::createDbgInfoPrinterPass() { return new PrintDbgInfo(); }

void PrintDbgInfo::printVariableDeclaration(const Value *V) {
  std::string DisplayName, File, Directory, Type;
  unsigned LineNo;

  if (!getLocationInfo(V, DisplayName, Type, LineNo, File, Directory))
    return;

  Out << "; ";
  WriteAsOperand(Out, V, false, 0);
  Out << " is variable " << DisplayName
      << " of type " << Type << " declared at ";

  if (PrintDirectory)
    Out << Directory << "/";

  Out << File << ":" << LineNo << "\n";
}

void PrintDbgInfo::printStopPoint(const DbgStopPointInst *DSI) {
  if (PrintDirectory) {
    std::string dir;
    GetConstantStringInfo(DSI->getDirectory(), dir);
    Out << dir << "/";
  }

  std::string file;
  GetConstantStringInfo(DSI->getFileName(), file);
  Out << file << ":" << DSI->getLine();

  if (unsigned Col = DSI->getColumn())
    Out << ":" << Col;
}

void PrintDbgInfo::printFuncStart(const DbgFuncStartInst *FS) {
  DISubprogram Subprogram(FS->getSubprogram());
  Out << "; fully qualified function name: " << Subprogram.getDisplayName()
      << " return type: " << Subprogram.getReturnTypeName()
      << " at line " << Subprogram.getLineNumber()
      << "\n\n";
}

bool PrintDbgInfo::runOnFunction(Function &F) {
  if (F.isDeclaration())
    return false;

  Out << "function " << F.getName() << "\n\n";

  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
    BasicBlock *BB = I;

    if (I != F.begin() && (pred_begin(BB) == pred_end(BB)))
      // Skip dead blocks.
      continue;

    const DbgStopPointInst *DSI = findBBStopPoint(BB);
    Out << BB->getName();
    Out << ":";

    if (DSI) {
      Out << "; (";
      printStopPoint(DSI);
      Out << ")";
    }

    Out << "\n";

    // A dbgstoppoint's information is valid until we encounter a new one.
    const DbgStopPointInst *LastDSP = DSI;
    bool Printed = DSI != 0;
    for (BasicBlock::const_iterator i = BB->begin(), e = BB->end();
         i != e; ++i) {
      if (isa<DbgInfoIntrinsic>(i)) {
        if ((DSI = dyn_cast<DbgStopPointInst>(i))) {
          if (DSI->getContext() == LastDSP->getContext() &&
              DSI->getLineValue() == LastDSP->getLineValue() &&
              DSI->getColumnValue() == LastDSP->getColumnValue())
            // Don't print same location twice.
            continue;

          LastDSP = cast<DbgStopPointInst>(i);

          // Don't print consecutive stoppoints, use a flag to know which one we
          // printed.
          Printed = false;
        } else if (const DbgFuncStartInst *FS = dyn_cast<DbgFuncStartInst>(i)) {
          printFuncStart(FS);
        }
      } else {
        if (!Printed && LastDSP) {
          Out << "; ";
          printStopPoint(LastDSP);
          Out << "\n";
          Printed = true;
        }

        Out << *i << '\n';
        printVariableDeclaration(i);

        if (const User *U = dyn_cast<User>(i)) {
          for(unsigned i=0;i<U->getNumOperands();i++)
            printVariableDeclaration(U->getOperand(i));
        }
      }
    }
  }

  return false;
}
