lib/Debugger/ProgramInfo.cpp - llvm - Git at Google

 //===-- 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/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Debugger/SourceFile.h"
 #include "llvm/Debugger/SourceLanguage.h"
 #include "llvm/Support/SlowOperationInformer.h"
 #include "llvm/ADT/STLExtras.h"
 #include <iostream>

 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->isString()) {
         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 (GlobalValue *GV = dyn_cast<GlobalValue>(C))
       return getStringValue(GV, 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 ((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.
     sys::Path tmpPath;
     if (!Directory.empty())
       tmpPath.set(Directory);
     tmpPath.appendComponent(BaseName);
     if (tmpPath.canRead())
       SourceText = new SourceFile(tmpPath.toString(), 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 GlobalVariable *GV =
             dyn_cast<GlobalVariable>(CS->getOperand(1)))
           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), ProgramTimeStamp(0,0) {
   assert(M && "Cannot create program information with a null module!");
   sys::Path modulePath(M->getModuleIdentifier());
   ProgramTimeStamp = modulePath.getTimestamp();

   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 GlobalVariable *GV =
             dyn_cast<GlobalVariable>(CS->getOperand(1)))
           SourceFileDesc = GV;

   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;
 }
	//===-- 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/Instructions.h"
	#include "llvm/Module.h"
	#include "llvm/Debugger/SourceFile.h"
	#include "llvm/Debugger/SourceLanguage.h"
	#include "llvm/Support/SlowOperationInformer.h"
	#include "llvm/ADT/STLExtras.h"
	#include <iostream>

	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->isString()) {
	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 (GlobalValue *GV = dyn_cast<GlobalValue>(C))
	return getStringValue(GV, 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 ((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.
	sys::Path tmpPath;
	if (!Directory.empty())
	tmpPath.set(Directory);
	tmpPath.appendComponent(BaseName);
	if (tmpPath.canRead())
	SourceText = new SourceFile(tmpPath.toString(), 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 GlobalVariable *GV =
	dyn_cast<GlobalVariable>(CS->getOperand(1)))
	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), ProgramTimeStamp(0,0) {
	assert(M && "Cannot create program information with a null module!");
	sys::Path modulePath(M->getModuleIdentifier());
	ProgramTimeStamp = modulePath.getTimestamp();

	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 GlobalVariable *GV =
	dyn_cast<GlobalVariable>(CS->getOperand(1)))
	SourceFileDesc = GV;

	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;
	}