Initial checkin of the LLVM source-level debugger. This is still not finished,

by any stretch of the imagination, but it is pretty cool and works :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10685 91177308-0d34-0410-b5e6-96231b3b80d8

11 files changed, 1983 insertions, 0 deletions

diff --git a/lib/Debugger/Debugger.cpp b/lib/Debugger/Debugger.cpp
new file mode 100644
index 0000000000..fd11f23b37
--- /dev/null
+++ b/lib/Debugger/Debugger.cpp
@@ -0,0 +1,212 @@
+//===-- Debugger.cpp - LLVM debugger library implementation ---------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file contains the main implementation of the LLVM debugger library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Debugger/Debugger.h"
+#include "llvm/Module.h"
+#include "llvm/ModuleProvider.h"
+#include "llvm/Bytecode/Reader.h"
+#include "llvm/Debugger/InferiorProcess.h"
+#include "Support/StringExtras.h"
+using namespace llvm;
+
+/// Debugger constructor - Initialize the debugger to its initial, empty, state.
+///
+Debugger::Debugger() : Environment(0), Program(0), Process(0) {
+}
+
+Debugger::~Debugger() {
+  // Killing the program could throw an exception.  We don't want to progagate
+  // the exception out of our destructor though.
+  try {
+    killProgram();
+  } catch (const char *) {
+  } catch (const std::string &) {
+  }
+  
+  unloadProgram();
+}
+
+/// getProgramPath - Get the path of the currently loaded program, or an
+/// empty string if none is loaded.
+std::string Debugger::getProgramPath() const {
+  return Program ? Program->getModuleIdentifier() : "";
+}
+
+static Module *
+getMaterializedModuleProvider(const std::string &Filename) {
+  try {
+    std::auto_ptr<ModuleProvider> Result(getBytecodeModuleProvider(Filename));
+    if (!Result.get()) return 0;
+  
+    Result->materializeModule();
+    return Result.release()->releaseModule();
+  } catch (...) {
+    return 0;
+  }
+}
+
+/// loadProgram - If a program is currently loaded, unload it.  Then search
+/// the PATH for the specified program, loading it when found.  If the
+/// specified program cannot be found, an exception is thrown to indicate the
+/// error.
+void Debugger::loadProgram(const std::string &Filename) {
+  if ((Program = getMaterializedModuleProvider(Filename)) ||
+      (Program = getMaterializedModuleProvider(Filename+".bc")))
+    return;   // Successfully loaded the program.
+
+  // Search the program path for the file...
+  if (const char *PathS = getenv("PATH")) {
+    std::string Path = PathS;
+
+    std::string Directory = getToken(Path, ":");
+    while (!Directory.empty()) {
+      if ((Program = getMaterializedModuleProvider(Directory +"/"+ Filename)) ||
+          (Program = getMaterializedModuleProvider(Directory +"/"+ Filename
+                                                                      + ".bc")))
+        return;   // Successfully loaded the program.
+
+      Directory = getToken(Path, ":");
+    }
+  }
+
+  throw "Could not find program '" + Filename + "'!";
+}
+
+/// unloadProgram - If a program is running, kill it, then unload all traces
+/// of the current program.  If no program is loaded, this method silently
+/// succeeds.
+void Debugger::unloadProgram() {
+  if (!isProgramLoaded()) return;
+  killProgram();
+  delete Program;
+  Program = 0;
+}
+
+
+/// createProgram - Create an instance of the currently loaded program,
+/// killing off any existing one.  This creates the program and stops it at
+/// the first possible moment.  If there is no program loaded or if there is a
+/// problem starting the program, this method throws an exception.
+void Debugger::createProgram() {
+  if (!isProgramLoaded())
+    throw "Cannot start program: none is loaded.";
+
+  // Kill any existing program.
+  killProgram();
+
+  // Add argv[0] to the arguments vector..
+  std::vector<std::string> Args(ProgramArguments);
+  Args.insert(Args.begin(), getProgramPath());
+
+  // Start the new program... this could throw if the program cannot be started.
+  Process = InferiorProcess::create(Program, Args, Environment);
+}
+
+/// killProgram - If the program is currently executing, kill off the
+/// process and free up any state related to the currently running program.  If
+/// there is no program currently running, this just silently succeeds.
+void Debugger::killProgram() {
+  // The destructor takes care of the dirty work.
+  delete Process;
+  Process = 0;
+}
+
+/// stepProgram - Implement the 'step' command, continuing execution until
+/// the next possible stop point.
+void Debugger::stepProgram() {
+  assert(isProgramRunning() && "Cannot step if the program isn't running!");
+  try {
+    Process->stepProgram();
+  } catch (InferiorProcessDead &IPD) {
+    delete Process;
+    Process = 0;
+    throw NonErrorException("The program stopped with exit code " +
+                            itostr(IPD.getExitCode()));
+  }
+}
+
+/// nextProgram - Implement the 'next' command, continuing execution until
+/// the next possible stop point that is in the current function.
+void Debugger::nextProgram() {
+  assert(isProgramRunning() && "Cannot next if the program isn't running!");
+  try {
+    // This should step the process.  If the process enters a function, then it
+    // should 'finish' it.  However, figuring this out is tricky.  In
+    // particular, the program can do any of:
+    //  0. Not change current frame.
+    //  1. Entering or exiting a region within the current function
+    //     (which changes the frame ID, but which we shouldn't 'finish')
+    //  2. Exiting the current function (which changes the frame ID)
+    //  3. Entering a function (which should be 'finish'ed)
+    // For this reason, we have to be very careful about when we decide to do
+    // the 'finish'.
+
+    // Get the current frame, but don't trust it.  It could change...
+    void *CurrentFrame = Process->getPreviousFrame(0);
+
+    // Don't trust the current frame: get the caller frame.
+    void *ParentFrame  = Process->getPreviousFrame(CurrentFrame);
+    
+    // Ok, we have some information, run the program one step.
+    Process->stepProgram();
+
+    // Where is the new frame?  The most common case, by far is that it has not
+    // been modified (Case #0), in which case we don't need to do anything more.
+    void *NewFrame = Process->getPreviousFrame(0);
+    if (NewFrame != CurrentFrame) {
+      // Ok, the frame changed.  If we are case #1, then the parent frame will
+      // be identical.
+      void *NewParentFrame = Process->getPreviousFrame(NewFrame);
+      if (ParentFrame != NewParentFrame) {
+        // Ok, now we know we aren't case #0 or #1.  Check to see if we entered
+        // a new function.  If so, the parent frame will be "CurrentFrame".
+        if (CurrentFrame == NewParentFrame)
+          Process->finishProgram(NewFrame);
+      }
+    }
+
+  } catch (InferiorProcessDead &IPD) {
+    delete Process;
+    Process = 0;
+    throw NonErrorException("The program stopped with exit code " +
+                            itostr(IPD.getExitCode()));
+  }
+}
+
+/// finishProgram - Implement the 'finish' command, continuing execution
+/// until the specified frame ID returns.
+void Debugger::finishProgram(void *Frame) {
+  assert(isProgramRunning() && "Cannot cont if the program isn't running!");
+  try {
+    Process->finishProgram(Frame);
+  } catch (InferiorProcessDead &IPD) {
+    delete Process;
+    Process = 0;
+    throw NonErrorException("The program stopped with exit code " +
+                            itostr(IPD.getExitCode()));
+  }
+}
+
+/// contProgram - Implement the 'cont' command, continuing execution until
+/// the next breakpoint is encountered.
+void Debugger::contProgram() {
+  assert(isProgramRunning() && "Cannot cont if the program isn't running!");
+  try {
+    Process->contProgram();
+  } catch (InferiorProcessDead &IPD) {
+    delete Process;
+    Process = 0;
+    throw NonErrorException("The program stopped with exit code " +
+                            itostr(IPD.getExitCode()));
+  }
+}
diff --git a/lib/Debugger/Makefile b/lib/Debugger/Makefile
new file mode 100644
index 0000000000..1cb6e0d21d
--- /dev/null
+++ b/lib/Debugger/Makefile
@@ -0,0 +1,13 @@
+##===- lib/Debugger/Makefile -------------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file was developed by the LLVM research group and is distributed under
+# the University of Illinois Open Source License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+LIBRARYNAME = debugger
+
+include $(LEVEL)/Makefile.common
diff --git a/lib/Debugger/ProgramInfo.cpp b/lib/Debugger/ProgramInfo.cpp
new file mode 100644
index 0000000000..46584a942c
--- /dev/null
+++ b/lib/Debugger/ProgramInfo.cpp
@@ -0,0 +1,409 @@
+//===-- ProgramInfo.cpp - Compute and cache info about a program ----------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file implements the ProgramInfo and related classes, by sorting through
+// the loaded Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Debugger/ProgramInfo.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/iOther.h"
+#include "llvm/Module.h"
+#include "llvm/Debugger/SourceFile.h"
+#include "llvm/Debugger/SourceLanguage.h"
+#include "Support/FileUtilities.h"
+#include "Support/SlowOperationInformer.h"
+#include "Support/STLExtras.h"
+using namespace llvm;
+
+/// getGlobalVariablesUsing - Return all of the global variables which have the
+/// specified value in their initializer somewhere.
+static void getGlobalVariablesUsing(Value *V,
+                                    std::vector<GlobalVariable*> &Found) {
+  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
+    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I))
+      Found.push_back(GV);
+    else if (Constant *C = dyn_cast<Constant>(*I))
+      getGlobalVariablesUsing(C, Found);
+  }
+}
+
+/// getStringValue - Turn an LLVM constant pointer that eventually points to a
+/// global into a string value.  Return an empty string if we can't do it.
+///
+static std::string getStringValue(Value *V, unsigned Offset = 0) {
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
+    if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
+      ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
+      if (Init->getType()->getElementType() == Type::SByteTy ||
+          Init->getType()->getElementType() == Type::UByteTy) {
+        std::string Result = Init->getAsString();
+        if (Offset < Result.size()) {
+          // If we are pointing INTO The string, erase the beginning...
+          Result.erase(Result.begin(), Result.begin()+Offset);
+
+          // Take off the null terminator, and any string fragments after it.
+          std::string::size_type NullPos = Result.find_first_of((char)0);
+          if (NullPos != std::string::npos)
+            Result.erase(Result.begin()+NullPos, Result.end());
+          return Result;
+        }
+      }
+    }
+  } else if (Constant *C = dyn_cast<Constant>(V)) {
+    if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C))
+      return getStringValue(CPR->getValue(), Offset);
+    else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
+      if (CE->getOpcode() == Instruction::GetElementPtr) {
+        // Turn a gep into the specified offset.
+        if (CE->getNumOperands() == 3 &&
+            cast<Constant>(CE->getOperand(1))->isNullValue() &&
+            isa<ConstantInt>(CE->getOperand(2))) {
+          return getStringValue(CE->getOperand(0),
+                   Offset+cast<ConstantInt>(CE->getOperand(2))->getRawValue());
+        }
+      }
+    }
+  }
+  return "";
+}
+
+/// getNextStopPoint - Follow the def-use chains of the specified LLVM value,
+/// traversing the use chains until we get to a stoppoint.  When we do, return
+/// the source location of the stoppoint.  If we don't find a stoppoint, return
+/// null.
+static const GlobalVariable *getNextStopPoint(const Value *V, unsigned &LineNo,
+                                              unsigned &ColNo) {
+  // The use-def chains can fork.  As such, we pick the lowest numbered one we
+  // find.
+  const GlobalVariable *LastDesc = 0;
+  unsigned LastLineNo = ~0;
+  unsigned LastColNo = ~0;
+
+  for (Value::use_const_iterator UI = V->use_begin(), E = V->use_end();
+       UI != E; ++UI) {
+    bool ShouldRecurse = true;
+    if (cast<Instruction>(*UI)->getOpcode() == Instruction::PHI) {
+      // Infinite loops == bad, ignore PHI nodes.
+      ShouldRecurse = false;
+    } else if (const CallInst *CI = dyn_cast<CallInst>(*UI)) {
+      // If we found a stop point, check to see if it is earlier than what we
+      // already have.  If so, remember it.
+      if (const Function *F = CI->getCalledFunction())
+        if (F->getIntrinsicID() == Intrinsic::dbg_stoppoint) {
+          unsigned CurLineNo = ~0, CurColNo = ~0;
+          const GlobalVariable *CurDesc = 0;
+          if (const ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
+            CurLineNo = C->getRawValue();
+          if (const ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
+            CurColNo = C->getRawValue();
+          const Value *Op = CI->getOperand(4);
+          if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Op))
+            Op = CPR->getValue();
+          
+          if ((CurDesc = dyn_cast<GlobalVariable>(Op)) &&
+              (LineNo < LastLineNo ||
+               (LineNo == LastLineNo && ColNo < LastColNo))) {
+            LastDesc = CurDesc;
+            LastLineNo = CurLineNo;
+            LastColNo = CurColNo;            
+          }
+          ShouldRecurse = false;
+        }
+
+    }
+
+    // If this is not a phi node or a stopping point, recursively scan the users
+    // of this instruction to skip over region.begin's and the like.
+    if (ShouldRecurse) {
+      unsigned CurLineNo, CurColNo;
+      if (const GlobalVariable *GV = getNextStopPoint(*UI, CurLineNo,CurColNo)){
+        if (LineNo < LastLineNo || (LineNo == LastLineNo && ColNo < LastColNo)){
+          LastDesc = GV;
+          LastLineNo = CurLineNo;
+          LastColNo = CurColNo;            
+        }
+      }
+    }
+  }
+  
+  if (LastDesc) {
+    LineNo = LastLineNo != ~0U ? LastLineNo : 0;
+    ColNo  = LastColNo  != ~0U ? LastColNo : 0;
+  }
+  return LastDesc;
+}
+
+
+//===----------------------------------------------------------------------===//
+// SourceFileInfo implementation
+//
+
+SourceFileInfo::SourceFileInfo(const GlobalVariable *Desc,
+                               const SourceLanguage &Lang)
+  : Language(&Lang), Descriptor(Desc) {
+  Version = 0;
+  SourceText = 0;
+
+  if (Desc && Desc->hasInitializer())
+    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
+      if (CS->getNumOperands() > 4) {
+        if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(CS->getOperand(1)))
+          Version = CUI->getValue();
+        
+        BaseName  = getStringValue(CS->getOperand(3));
+        Directory = getStringValue(CS->getOperand(4));
+      }
+}
+
+SourceFileInfo::~SourceFileInfo() {
+  delete SourceText;
+}
+
+SourceFile &SourceFileInfo::getSourceText() const {
+  // FIXME: this should take into account the source search directories!
+  if (SourceText == 0)  // Read the file in if we haven't already.
+    if (!Directory.empty() && FileOpenable(Directory+"/"+BaseName))
+      SourceText = new SourceFile(Directory+"/"+BaseName, Descriptor);
+    else
+      SourceText = new SourceFile(BaseName, Descriptor);
+  return *SourceText;
+}
+
+
+//===----------------------------------------------------------------------===//
+// SourceFunctionInfo implementation
+//
+SourceFunctionInfo::SourceFunctionInfo(ProgramInfo &PI,
+                                       const GlobalVariable *Desc)
+  : Descriptor(Desc) {
+  LineNo = ColNo = 0;
+  if (Desc && Desc->hasInitializer())
+    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
+      if (CS->getNumOperands() > 2) {
+        // Entry #1 is the file descriptor.
+        if (const ConstantPointerRef *CPR =
+            dyn_cast<ConstantPointerRef>(CS->getOperand(1)))
+          if (const GlobalVariable *GV =
+              dyn_cast<GlobalVariable>(CPR->getValue()))
+            SourceFile = &PI.getSourceFile(GV);
+
+        // Entry #2 is the function name.
+        Name = getStringValue(CS->getOperand(2));
+      }
+}
+
+/// getSourceLocation - This method returns the location of the first stopping
+/// point in the function.
+void SourceFunctionInfo::getSourceLocation(unsigned &RetLineNo,
+                                           unsigned &RetColNo) const {
+  // If we haven't computed this yet...
+  if (!LineNo) {
+    // Look at all of the users of the function descriptor, looking for calls to
+    // %llvm.dbg.func.start.
+    for (Value::use_const_iterator UI = Descriptor->use_begin(),
+           E = Descriptor->use_end(); UI != E; ++UI)
+      if (const CallInst *CI = dyn_cast<CallInst>(*UI))
+        if (const Function *F = CI->getCalledFunction())
+          if (F->getIntrinsicID() == Intrinsic::dbg_func_start) {
+            // We found the start of the function.  Check to see if there are
+            // any stop points on the use-list of the function start.
+            const GlobalVariable *SD = getNextStopPoint(CI, LineNo, ColNo);
+            if (SD) {             // We found the first stop point!
+              // This is just a sanity check.
+              if (getSourceFile().getDescriptor() != SD)
+                std::cout << "WARNING: first line of function is not in the"
+                  " file that the function descriptor claims it is in.\n";
+              break;
+            }
+          }
+  }
+  RetLineNo = LineNo; RetColNo = ColNo;
+}
+
+//===----------------------------------------------------------------------===//
+// ProgramInfo implementation
+//
+
+ProgramInfo::ProgramInfo(Module *m) : M(m) {
+  assert(M && "Cannot create program information with a null module!");
+  ProgramTimeStamp = getFileTimestamp(M->getModuleIdentifier());
+
+  SourceFilesIsComplete = false;
+  SourceFunctionsIsComplete = false;
+}
+
+ProgramInfo::~ProgramInfo() {
+  // Delete cached information about source program objects...
+  for (std::map<const GlobalVariable*, SourceFileInfo*>::iterator
+         I = SourceFiles.begin(), E = SourceFiles.end(); I != E; ++I)
+    delete I->second;
+  for (std::map<const GlobalVariable*, SourceFunctionInfo*>::iterator
+         I = SourceFunctions.begin(), E = SourceFunctions.end(); I != E; ++I)
+    delete I->second;
+
+  // Delete the source language caches.
+  for (unsigned i = 0, e = LanguageCaches.size(); i != e; ++i)
+    delete LanguageCaches[i].second;
+}
+
+
+//===----------------------------------------------------------------------===//
+// SourceFileInfo tracking...
+//
+
+/// getSourceFile - Return source file information for the specified source file
+/// descriptor object, adding it to the collection as needed.  This method
+/// always succeeds (is unambiguous), and is always efficient.
+///
+const SourceFileInfo &
+ProgramInfo::getSourceFile(const GlobalVariable *Desc) {
+  SourceFileInfo *&Result = SourceFiles[Desc];
+  if (Result) return *Result;
+
+  // Figure out what language this source file comes from...
+  unsigned LangID = 0;   // Zero is unknown language
+  if (Desc && Desc->hasInitializer())
+    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
+      if (CS->getNumOperands() > 2)
+        if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(CS->getOperand(2)))
+          LangID = CUI->getValue();
+
+  const SourceLanguage &Lang = SourceLanguage::get(LangID);
+  SourceFileInfo *New = Lang.createSourceFileInfo(Desc, *this);
+
+  // FIXME: this should check to see if there is already a Filename/WorkingDir
+  // pair that matches this one.  If so, we shouldn't create the duplicate!
+  //
+  SourceFileIndex.insert(std::make_pair(New->getBaseName(), New));
+  return *(Result = New);
+}
+
+
+/// getSourceFiles - Index all of the source files in the program and return
+/// a mapping of it.  This information is lazily computed the first time
+/// that it is requested.  Since this information can take a long time to
+/// compute, the user is given a chance to cancel it.  If this occurs, an
+/// exception is thrown.
+const std::map<const GlobalVariable*, SourceFileInfo*> &
+ProgramInfo::getSourceFiles(bool RequiresCompleteMap) {
+  // If we have a fully populated map, or if the client doesn't need one, just
+  // return what we have.
+  if (SourceFilesIsComplete || !RequiresCompleteMap)
+    return SourceFiles;
+
+  // Ok, all of the source file descriptors (compile_unit in dwarf terms),
+  // should be on the use list of the llvm.dbg.translation_units global.
+  //
+  GlobalVariable *Units =
+    M->getGlobalVariable("llvm.dbg.translation_units",
+                         StructType::get(std::vector<const Type*>()));
+  if (Units == 0)
+    throw "Program contains no debugging information!";
+
+  std::vector<GlobalVariable*> TranslationUnits;
+  getGlobalVariablesUsing(Units, TranslationUnits);
+
+  SlowOperationInformer SOI("building source files index");
+
+  // Loop over all of the translation units found, building the SourceFiles
+  // mapping.
+  for (unsigned i = 0, e = TranslationUnits.size(); i != e; ++i) {
+    getSourceFile(TranslationUnits[i]);
+    SOI.progress(i+1, e);
+  }
+
+  // Ok, if we got this far, then we indexed the whole program.
+  SourceFilesIsComplete = true;
+  return SourceFiles;
+}
+
+/// getSourceFile - Look up the file with the specified name.  If there is
+/// more than one match for the specified filename, prompt the user to pick
+/// one.  If there is no source file that matches the specified name, throw
+/// an exception indicating that we can't find the file.  Otherwise, return
+/// the file information for that file.
+const SourceFileInfo &ProgramInfo::getSourceFile(const std::string &Filename) {
+  std::multimap<std::string, SourceFileInfo*>::const_iterator Start, End;
+  getSourceFiles();
+  tie(Start, End) = SourceFileIndex.equal_range(Filename);
+  
+  if (Start == End) throw "Could not find source file '" + Filename + "'!";
+  const SourceFileInfo &SFI = *Start->second;
+  ++Start;
+  if (Start == End) return SFI;
+
+  throw "FIXME: Multiple source files with the same name not implemented!";
+}
+
+
+//===----------------------------------------------------------------------===//
+// SourceFunctionInfo tracking...
+//
+
+
+/// getFunction - Return function information for the specified function
+/// descriptor object, adding it to the collection as needed.  This method
+/// always succeeds (is unambiguous), and is always efficient.
+///
+const SourceFunctionInfo &
+ProgramInfo::getFunction(const GlobalVariable *Desc) {
+  SourceFunctionInfo *&Result = SourceFunctions[Desc];
+  if (Result) return *Result;
+
+  // Figure out what language this function comes from...
+  const GlobalVariable *SourceFileDesc = 0;
+  if (Desc && Desc->hasInitializer())
+    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
+      if (CS->getNumOperands() > 0)
+        if (const ConstantPointerRef *CPR =
+            dyn_cast<ConstantPointerRef>(CS->getOperand(1)))
+          SourceFileDesc = dyn_cast<GlobalVariable>(CPR->getValue());
+
+  const SourceLanguage &Lang = getSourceFile(SourceFileDesc).getLanguage();
+  return *(Result = Lang.createSourceFunctionInfo(Desc, *this));
+}
+
+
+// getSourceFunctions - Index all of the functions in the program and return
+// them.  This information is lazily computed the first time that it is
+// requested.  Since this information can take a long time to compute, the user
+// is given a chance to cancel it.  If this occurs, an exception is thrown.
+const std::map<const GlobalVariable*, SourceFunctionInfo*> &
+ProgramInfo::getSourceFunctions(bool RequiresCompleteMap) {
+  if (SourceFunctionsIsComplete || !RequiresCompleteMap)
+    return SourceFunctions;
+
+  // Ok, all of the source function descriptors (subprogram in dwarf terms),
+  // should be on the use list of the llvm.dbg.translation_units global.
+  //
+  GlobalVariable *Units =
+    M->getGlobalVariable("llvm.dbg.globals",
+                         StructType::get(std::vector<const Type*>()));
+  if (Units == 0)
+    throw "Program contains no debugging information!";
+
+  std::vector<GlobalVariable*> Functions;
+  getGlobalVariablesUsing(Units, Functions);
+
+  SlowOperationInformer SOI("building functions index");
+
+  // Loop over all of the functions found, building the SourceFunctions mapping.
+  for (unsigned i = 0, e = Functions.size(); i != e; ++i) {
+    getFunction(Functions[i]);
+    SOI.progress(i+1, e);
+  }
+
+  // Ok, if we got this far, then we indexed the whole program.
+  SourceFunctionsIsComplete = true;
+  return SourceFunctions;
+}
diff --git a/lib/Debugger/README.txt b/lib/Debugger/README.txt
new file mode 100644
index 0000000000..04a18febc6
--- /dev/null
+++ b/lib/Debugger/README.txt
@@ -0,0 +1,8 @@
+//===-- llvm/lib/Debugger/ - LLVM Debugger interfaces ---------------------===//
+
+This directory contains the implementation of the LLVM debugger backend.  This
+directory builds into a library which can be used by various debugger 
+front-ends to debug LLVM programs.  The current command line LLVM debugger, 
+llvm-db is currently the only client of this library, but others could be 
+built, to provide a GUI front-end for example.
+
diff --git a/lib/Debugger/RuntimeInfo.cpp b/lib/Debugger/RuntimeInfo.cpp
new file mode 100644
index 0000000000..d1bc48b543
--- /dev/null
+++ b/lib/Debugger/RuntimeInfo.cpp
@@ -0,0 +1,69 @@
+//===-- RuntimeInfo.cpp - Compute and cache info about running program ----===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file implements the RuntimeInfo and related classes, by querying and
+// cachine information from the running inferior process.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Debugger/InferiorProcess.h"
+#include "llvm/Debugger/ProgramInfo.h"
+#include "llvm/Debugger/RuntimeInfo.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// StackFrame class implementation
+
+StackFrame::StackFrame(RuntimeInfo &ri, void *ParentFrameID)
+  : RI(ri), SourceInfo(0) {
+  FrameID = RI.getInferiorProcess().getPreviousFrame(ParentFrameID);
+  if (FrameID == 0) throw "Stack frame does not exist!";
+  
+  // Compute lazily as needed.
+  FunctionDesc = 0;
+}
+
+const GlobalVariable *StackFrame::getFunctionDesc() {
+  if (FunctionDesc == 0)
+    FunctionDesc = RI.getInferiorProcess().getSubprogramDesc(FrameID);
+  return FunctionDesc;
+}
+
+/// getSourceLocation - Return the source location that this stack frame is
+/// sitting at.
+void StackFrame::getSourceLocation(unsigned &lineNo, unsigned &colNo,
+                                   const SourceFileInfo *&sourceInfo) {
+  if (SourceInfo == 0) {
+    const GlobalVariable *SourceDesc = 0;
+    RI.getInferiorProcess().getFrameLocation(FrameID, LineNo,ColNo, SourceDesc);
+    SourceInfo = &RI.getProgramInfo().getSourceFile(SourceDesc);
+  }
+
+  lineNo = LineNo;
+  colNo = ColNo;
+  sourceInfo = SourceInfo;
+}
+
+//===----------------------------------------------------------------------===//
+// RuntimeInfo class implementation
+
+/// materializeFrame - Create and process all frames up to and including the
+/// specified frame number.  This throws an exception if the specified frame
+/// ID is nonexistant.
+void RuntimeInfo::materializeFrame(unsigned ID) {
+  assert(ID >= CallStack.size() && "no need to materialize this frame!");
+  void *CurFrame = 0;
+  if (!CallStack.empty())
+    CurFrame = CallStack.back().getFrameID();
+
+  while (CallStack.size() <= ID) {
+    CallStack.push_back(StackFrame(*this, CurFrame));
+    CurFrame = CallStack.back().getFrameID();
+  }
+}
diff --git a/lib/Debugger/SourceFile.cpp b/lib/Debugger/SourceFile.cpp
new file mode 100644
index 0000000000..2eb3b5750b
--- /dev/null
+++ b/lib/Debugger/SourceFile.cpp
@@ -0,0 +1,116 @@
+//===-- SourceFile.cpp - SourceFile implementation for the debugger -------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file implements the SourceFile class for the LLVM debugger.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Debugger/SourceFile.h"
+#include "Support/SlowOperationInformer.h"
+#include "Support/FileUtilities.h"
+#include <iostream>
+#include <cerrno>
+#include <fcntl.h>
+#include <unistd.h>
+using namespace llvm;
+
+/// readFile - Load Filename into FileStart and FileEnd.
+///
+void SourceFile::readFile() {
+  ssize_t FileSize = getFileSize(Filename);
+  if (FileSize != -1) {
+    FDHandle FD(open(Filename.c_str(), O_RDONLY));
+    if (FD != -1) {
+      char *FilePos = new char[FileSize];
+      FileStart = FilePos;
+
+      // If this takes a long time, inform the user what we are doing.
+      SlowOperationInformer SOI("loading source file '" + Filename + "'");
+
+      try {
+        // Read in the whole buffer.
+        unsigned Amount = FileSize;
+        while (Amount) {
+          unsigned AmountToRead = 512*1024;
+          if (Amount < AmountToRead) AmountToRead = Amount;
+          ssize_t ReadAmount = read(FD, FilePos, AmountToRead);
+          if (ReadAmount < 0 && errno == EINTR)
+            continue;
+          else if (ReadAmount <= 0) {
+            // Couldn't read whole file just free memory and continue.
+            throw "Error reading file '" + Filename + "'!";
+          }
+          Amount -= ReadAmount;
+          FilePos += ReadAmount;
+          
+          SOI.progress(FileSize-Amount, FileSize);
+        }
+
+      } catch (const std::string &Msg) {
+        std::cout << Msg << "\n";
+        // If the user cancels the operation, clean up after ourselves.
+        delete [] FileStart;
+        FileStart = 0;
+        return;
+      }
+      
+      FileEnd = FileStart+FileSize;
+    }
+  }
+}
+
+/// calculateLineOffsets - Compute the LineOffset vector for the current file.
+///
+void SourceFile::calculateLineOffsets() const {
+  assert(LineOffset.empty() && "Line offsets already computed!");
+  const char *BufPtr = FileStart;
+  do {
+    LineOffset.push_back(BufPtr-FileStart);
+
+    // Scan until we get to a newline.
+    while (BufPtr != FileEnd && *BufPtr != '\n' && *BufPtr != '\r')
+      ++BufPtr;
+
+    if (BufPtr != FileEnd) {
+      ++BufPtr;               // Skip over the \n or \r
+      if (BufPtr[-1] == '\r' && BufPtr != FileEnd && BufPtr[0] == '\n')
+        ++BufPtr;   // Skip over dos/windows style \r\n's
+    }
+  } while (BufPtr != FileEnd);
+}
+
+
+/// getSourceLine - Given a line number, return the start and end of the line
+/// in the file.  If the line number is invalid, or if the file could not be
+/// loaded, null pointers are returned for the start and end of the file. Note
+/// that line numbers start with 0, not 1.
+void SourceFile::getSourceLine(unsigned LineNo, const char *&LineStart,
+                               const char *&LineEnd) const {
+  LineStart = LineEnd = 0;
+  if (FileStart == 0) return;  // Couldn't load file, return null pointers
+  if (LineOffset.empty()) calculateLineOffsets();
+
+  // Asking for an out-of-range line number?
+  if (LineNo >= LineOffset.size()) return;
+
+  // Otherwise, they are asking for a valid line, which we can fulfill.
+  LineStart = FileStart+LineOffset[LineNo];
+
+  if (LineNo+1 < LineOffset.size())
+    LineEnd = FileStart+LineOffset[LineNo+1];
+  else
+    LineEnd = FileEnd;
+
+  // If the line ended with a newline, strip it off.
+  while (LineEnd != LineStart && (LineEnd[-1] == '\n' || LineEnd[-1] == '\r'))
+    --LineEnd;
+
+  assert(LineEnd >= LineStart && "We somehow got our pointers swizzled!");
+}
+ 
diff --git a/lib/Debugger/SourceLanguage-CFamily.cpp b/lib/Debugger/SourceLanguage-CFamily.cpp
new file mode 100644
index 0000000000..392c07c818
--- /dev/null
+++ b/lib/Debugger