DwarfDebug.cpp

//===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing dwarf debug info into asm files.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "dwarfdebug"
#include "DwarfDebug.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/Timer.h"
#include "llvm/System/Path.h"
using namespace llvm;

static TimerGroup &getDwarfTimerGroup() {
  static TimerGroup DwarfTimerGroup("Dwarf Debugging");
  return DwarfTimerGroup;
}

//===----------------------------------------------------------------------===//

/// Configuration values for initial hash set sizes (log2).
///
static const unsigned InitDiesSetSize          = 9; // log2(512)
static const unsigned InitAbbreviationsSetSize = 9; // log2(512)
static const unsigned InitValuesSetSize        = 9; // log2(512)

namespace llvm {

//===----------------------------------------------------------------------===//
/// CompileUnit - This dwarf writer support class manages information associate
/// with a source file.
class VISIBILITY_HIDDEN CompileUnit {
  /// ID - File identifier for source.
  ///
  unsigned ID;

  /// Die - Compile unit debug information entry.
  ///
  DIE *Die;

  /// GVToDieMap - Tracks the mapping of unit level debug informaton
  /// variables to debug information entries.
  /// FIXME : Rename GVToDieMap -> NodeToDieMap
  std::map<MDNode *, DIE *> GVToDieMap;

  /// GVToDIEEntryMap - Tracks the mapping of unit level debug informaton
  /// descriptors to debug information entries using a DIEEntry proxy.
  /// FIXME : Rename
  std::map<MDNode *, DIEEntry *> GVToDIEEntryMap;

  /// Globals - A map of globally visible named entities for this unit.
  ///
  StringMap<DIE*> Globals;

  /// DiesSet - Used to uniquely define dies within the compile unit.
  ///
  FoldingSet<DIE> DiesSet;
public:
  CompileUnit(unsigned I, DIE *D)
    : ID(I), Die(D), DiesSet(InitDiesSetSize) {}
  ~CompileUnit() { delete Die; }

  // Accessors.
  unsigned getID() const { return ID; }
  DIE* getDie() const { return Die; }
  StringMap<DIE*> &getGlobals() { return Globals; }

  /// hasContent - Return true if this compile unit has something to write out.
  ///
  bool hasContent() const { return !Die->getChildren().empty(); }

  /// AddGlobal - Add a new global entity to the compile unit.
  ///
  void AddGlobal(const std::string &Name, DIE *Die) { Globals[Name] = Die; }

  /// getDieMapSlotFor - Returns the debug information entry map slot for the
  /// specified debug variable.
  DIE *&getDieMapSlotFor(MDNode *N) { return GVToDieMap[N]; }

  /// getDIEEntrySlotFor - Returns the debug information entry proxy slot for
  /// the specified debug variable.
  DIEEntry *&getDIEEntrySlotFor(MDNode *N) {
    return GVToDIEEntryMap[N];
  }

  /// AddDie - Adds or interns the DIE to the compile unit.
  ///
  DIE *AddDie(DIE &Buffer) {
    FoldingSetNodeID ID;
    Buffer.Profile(ID);
    void *Where;
    DIE *Die = DiesSet.FindNodeOrInsertPos(ID, Where);

    if (!Die) {
      Die = new DIE(Buffer);
      DiesSet.InsertNode(Die, Where);
      this->Die->AddChild(Die);
      Buffer.Detach();
    }

    return Die;
  }
};

//===----------------------------------------------------------------------===//
/// DbgVariable - This class is used to track local variable information.
///
class VISIBILITY_HIDDEN DbgVariable {
  DIVariable Var;                    // Variable Descriptor.
  unsigned FrameIndex;               // Variable frame index.
  bool InlinedFnVar;                 // Variable for an inlined function.
public:
  DbgVariable(DIVariable V, unsigned I, bool IFV)
    : Var(V), FrameIndex(I), InlinedFnVar(IFV)  {}

  // Accessors.
  DIVariable getVariable() const { return Var; }
  unsigned getFrameIndex() const { return FrameIndex; }
  bool isInlinedFnVar() const { return InlinedFnVar; }
};

//===----------------------------------------------------------------------===//
/// DbgScope - This class is used to track scope information.
///
class DbgConcreteScope;
class VISIBILITY_HIDDEN DbgScope {
  DbgScope *Parent;                   // Parent to this scope.
  DIDescriptor Desc;                  // Debug info descriptor for scope.
                                      // FIXME use WeakVH for Desc.
  WeakVH InlinedAt;                   // If this scope represents inlined
                                      // function body then this is the location
                                      // where this body is inlined.
  unsigned StartLabelID;              // Label ID of the beginning of scope.
  unsigned EndLabelID;                // Label ID of the end of scope.
  const MachineInstr *LastInsn;       // Last instruction of this scope.
  const MachineInstr *FirstInsn;      // First instruction of this scope.
  SmallVector<DbgScope *, 4> Scopes;  // Scopes defined in scope.
  SmallVector<DbgVariable *, 8> Variables;// Variables declared in scope.
  SmallVector<DbgConcreteScope *, 8> ConcreteInsts;// Concrete insts of funcs.

  // Private state for dump()
  mutable unsigned IndentLevel;
public:
  DbgScope(DbgScope *P, DIDescriptor D, MDNode *I = 0)
    : Parent(P), Desc(D), InlinedAt(I), StartLabelID(0), EndLabelID(0), 
      LastInsn(0), FirstInsn(0), IndentLevel(0) {}
  virtual ~DbgScope();

  // Accessors.
  DbgScope *getParent()          const { return Parent; }
  DIDescriptor getDesc()         const { return Desc; }
  MDNode *getInlinedAt()   const { 
    return dyn_cast_or_null<MDNode>(InlinedAt); 
  }
  unsigned getStartLabelID()     const { return StartLabelID; }
  unsigned getEndLabelID()       const { return EndLabelID; }
  SmallVector<DbgScope *, 4> &getScopes() { return Scopes; }
  SmallVector<DbgVariable *, 8> &getVariables() { return Variables; }
  SmallVector<DbgConcreteScope*,8> &getConcreteInsts() { return ConcreteInsts; }
  void setStartLabelID(unsigned S) { StartLabelID = S; }
  void setEndLabelID(unsigned E)   { EndLabelID = E; }
  void setLastInsn(const MachineInstr *MI) { LastInsn = MI; }
  const MachineInstr *getLastInsn()      { return LastInsn; }
  void setFirstInsn(const MachineInstr *MI) { FirstInsn = MI; }
  const MachineInstr *getFirstInsn()      { return FirstInsn; }
  /// AddScope - Add a scope to the scope.
  ///
  void AddScope(DbgScope *S) { Scopes.push_back(S); }

  /// AddVariable - Add a variable to the scope.
  ///
  void AddVariable(DbgVariable *V) { Variables.push_back(V); }

  /// AddConcreteInst - Add a concrete instance to the scope.
  ///
  void AddConcreteInst(DbgConcreteScope *C) { ConcreteInsts.push_back(C); }

  void FixInstructionMarkers() {
    assert (getFirstInsn() && "First instruction is missing!");
    if (getLastInsn())
      return;