-//===- Pass.cpp - LLVM Pass Infrastructure Impementation ------------------===//
+//===- Pass.cpp - LLVM Pass Infrastructure 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 implements the LLVM Pass infrastructure. It is primarily
// responsible with ensuring that passes are executed and batched together
//===----------------------------------------------------------------------===//
#include "llvm/PassManager.h"
+#ifdef USE_OLD_PASSMANAGER
#include "PassManagerT.h" // PassManagerT implementation
+#endif
#include "llvm/Module.h"
-#include "Support/STLExtras.h"
-#include "Support/TypeInfo.h"
-#include <typeinfo>
-#include <iostream>
-#include <sys/time.h>
-#include <stdio.h>
-
-//===----------------------------------------------------------------------===//
-// AnalysisID Class Implementation
-//
-
-static std::vector<const PassInfo*> CFGOnlyAnalyses;
-
-void RegisterPassBase::setPreservesCFG() {
- CFGOnlyAnalyses.push_back(PIObj);
-}
+#include "llvm/ModuleProvider.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/TypeInfo.h"
+#include <set>
+using namespace llvm;
//===----------------------------------------------------------------------===//
// AnalysisResolver Class Implementation
//
+AnalysisResolver::~AnalysisResolver() {
+}
void AnalysisResolver::setAnalysisResolver(Pass *P, AnalysisResolver *AR) {
assert(P->Resolver == 0 && "Pass already in a PassManager!");
P->Resolver = AR;
}
+#ifdef USE_OLD_PASSMANAGER
//===----------------------------------------------------------------------===//
-// AnalysisUsage Class Implementation
+// PassManager implementation - The PassManager class is a simple Pimpl class
+// that wraps the PassManagerT template.
//
+PassManager::PassManager() : PM(new ModulePassManager()) {}
+PassManager::~PassManager() { delete PM; }
+void PassManager::add(Pass *P) {
+ ModulePass *MP = dynamic_cast<ModulePass*>(P);
+ assert(MP && "Not a modulepass?");
+ PM->add(MP);
+}
+bool PassManager::run(Module &M) { return PM->runOnModule(M); }
-// preservesCFG - This function should be called to by the pass, iff they do
-// not:
-//
-// 1. Add or remove basic blocks from the function
-// 2. Modify terminator instructions in any way.
-//
-// This function annotates the AnalysisUsage info object to say that analyses
-// that only depend on the CFG are preserved by this pass.
+//===----------------------------------------------------------------------===//
+// FunctionPassManager implementation - The FunctionPassManager class
+// is a simple Pimpl class that wraps the PassManagerT template. It
+// is like PassManager, but only deals in FunctionPasses.
//
-void AnalysisUsage::preservesCFG() {
- // Since this transformation doesn't modify the CFG, it preserves all analyses
- // that only depend on the CFG (like dominators, loop info, etc...)
- //
- Preserved.insert(Preserved.end(),
- CFGOnlyAnalyses.begin(), CFGOnlyAnalyses.end());
+FunctionPassManager::FunctionPassManager(ModuleProvider *P) :
+ PM(new FunctionPassManagerT()), MP(P) {}
+FunctionPassManager::~FunctionPassManager() { delete PM; }
+void FunctionPassManager::add(FunctionPass *P) { PM->add(P); }
+void FunctionPassManager::add(ImmutablePass *IP) { PM->add(IP); }
+
+/// doInitialization - Run all of the initializers for the function passes.
+///
+bool FunctionPassManager::doInitialization() {
+ return PM->doInitialization(*MP->getModule());
}
+bool FunctionPassManager::run(Function &F) {
+ std::string errstr;
+ if (MP->materializeFunction(&F, &errstr)) {
+ cerr << "Error reading bytecode file: " << errstr << "\n";
+ abort();
+ }
+ return PM->runOnFunction(F);
+}
-//===----------------------------------------------------------------------===//
-// PassManager implementation - The PassManager class is a simple Pimpl class
-// that wraps the PassManagerT template.
-//
-PassManager::PassManager() : PM(new PassManagerT<Module>()) {}
-PassManager::~PassManager() { delete PM; }
-void PassManager::add(Pass *P) { PM->add(P); }
-bool PassManager::run(Module &M) { return PM->run(M); }
+/// doFinalization - Run all of the initializers for the function passes.
+///
+bool FunctionPassManager::doFinalization() {
+ return PM->doFinalization(*MP->getModule());
+}
//===----------------------------------------------------------------------===//
// amount of time each pass takes to execute. This only happens with
// -time-passes is enabled on the command line.
//
-static cl::opt<bool>
-EnableTiming("time-passes",
+bool llvm::TimePassesIsEnabled = false;
+static cl::opt<bool,true>
+EnableTiming("time-passes", cl::location(TimePassesIsEnabled),
cl::desc("Time each pass, printing elapsed time for each on exit"));
-static double getTime() {
- struct timeval T;
- gettimeofday(&T, 0);
- return T.tv_sec + T.tv_usec/1000000.0;
+// createTheTimeInfo - This method either initializes the TheTimeInfo pointer to
+// a non null value (if the -time-passes option is enabled) or it leaves it
+// null. It may be called multiple times.
+void TimingInfo::createTheTimeInfo() {
+ if (!TimePassesIsEnabled || TheTimeInfo) return;
+
+ // Constructed the first time this is called, iff -time-passes is enabled.
+ // This guarantees that the object will be constructed before static globals,
+ // thus it will be destroyed before them.
+ static ManagedStatic<TimingInfo> TTI;
+ TheTimeInfo = &*TTI;
}
-// Create method. If Timing is enabled, this creates and returns a new timing
-// object, otherwise it returns null.
-//
-TimingInfo *TimingInfo::create() {
- return EnableTiming ? new TimingInfo() : 0;
-}
-
-void TimingInfo::passStarted(Pass *P) { TimingData[P] -= getTime(); }
-void TimingInfo::passEnded(Pass *P) { TimingData[P] += getTime(); }
-
-// TimingDtor - Print out information about timing information
-TimingInfo::~TimingInfo() {
- // Iterate over all of the data, converting it into the dual of the data map,
- // so that the data is sorted by amount of time taken, instead of pointer.
- //
- std::vector<std::pair<double, Pass*> > Data;
- double TotalTime = 0;
- for (std::map<Pass*, double>::iterator I = TimingData.begin(),
- E = TimingData.end(); I != E; ++I)
- // Throw out results for "grouping" pass managers...
- if (!dynamic_cast<AnalysisResolver*>(I->first)) {
- Data.push_back(std::make_pair(I->second, I->first));
- TotalTime += I->second;
- }
-
- // Sort the data by time as the primary key, in reverse order...
- std::sort(Data.begin(), Data.end(), std::greater<std::pair<double, Pass*> >());
-
- // Print out timing header...
- std::cerr << std::string(79, '=') << "\n"
- << " ... Pass execution timing report ...\n"
- << std::string(79, '=') << "\n Total Execution Time: " << TotalTime
- << " seconds\n\n % Time: Seconds:\tPass Name:\n";
-
- // Loop through all of the timing data, printing it out...
- for (unsigned i = 0, e = Data.size(); i != e; ++i) {
- fprintf(stderr, " %6.2f%% %fs\t%s\n", Data[i].first*100 / TotalTime,
- Data[i].first, Data[i].second->getPassName());
- }
- std::cerr << " 100.00% " << TotalTime << "s\tTOTAL\n"
- << std::string(79, '=') << "\n";
-}
-
-
void PMDebug::PrintArgumentInformation(const Pass *P) {
// Print out passes in pass manager...
if (const AnalysisResolver *PM = dynamic_cast<const AnalysisResolver*>(P)) {
} else { // Normal pass. Print argument information...
// Print out arguments for registered passes that are _optimizations_
if (const PassInfo *PI = P->getPassInfo())
- if (PI->getPassType() & PassInfo::Optimization)
- std::cerr << " -" << PI->getPassArgument();
+ if (!PI->isAnalysisGroup())
+ cerr << " -" << PI->getPassArgument();
}
}
void PMDebug::PrintPassInformation(unsigned Depth, const char *Action,
- Pass *P, Annotable *V) {
- if (PassDebugging >= Executions) {
- std::cerr << (void*)P << std::string(Depth*2+1, ' ') << Action << " '"
- << P->getPassName();
- if (V) {
- std::cerr << "' on ";
-
- if (dynamic_cast<Module*>(V)) {
- std::cerr << "Module\n"; return;
- } else if (Function *F = dynamic_cast<Function*>(V))
- std::cerr << "Function '" << F->getName();
- else if (BasicBlock *BB = dynamic_cast<BasicBlock*>(V))
- std::cerr << "BasicBlock '" << BB->getName();
- else if (Value *Val = dynamic_cast<Value*>(V))
- std::cerr << typeid(*Val).name() << " '" << Val->getName();
- }
- std::cerr << "'...\n";
+ Pass *P, Module *M) {
+ if (PassDebugging >= PDLExecutions) {
+ cerr << (void*)P << std::string(Depth*2+1, ' ') << Action << " '"
+ << P->getPassName();
+ if (M) cerr << "' on Module '" << M->getModuleIdentifier() << "'\n";
+ cerr << "'...\n";
+ }
+}
+
+void PMDebug::PrintPassInformation(unsigned Depth, const char *Action,
+ Pass *P, Function *F) {
+ if (PassDebugging >= PDLExecutions) {
+ cerr << (void*)P << std::string(Depth*2+1, ' ') << Action << " '"
+ << P->getPassName();
+ if (F) cerr << "' on Function '" << F->getName();
+ cerr << "'...\n";
+ }
+}
+
+void PMDebug::PrintPassInformation(unsigned Depth, const char *Action,
+ Pass *P, BasicBlock *BB) {
+ if (PassDebugging >= PDLExecutions) {
+ cerr << (void*)P << std::string(Depth*2+1, ' ') << Action << " '"
+ << P->getPassName();
+ if (BB) cerr << "' on BasicBlock '" << BB->getName();
+ cerr << "'...\n";
}
}
void PMDebug::PrintAnalysisSetInfo(unsigned Depth, const char *Msg,
Pass *P, const std::vector<AnalysisID> &Set){
- if (PassDebugging >= Details && !Set.empty()) {
- std::cerr << (void*)P << std::string(Depth*2+3, ' ') << Msg << " Analyses:";
- for (unsigned i = 0; i != Set.size(); ++i)
- std::cerr << " " << Set[i]->getPassName();
- std::cerr << "\n";
+ if (PassDebugging >= PDLDetails && !Set.empty()) {
+ cerr << (void*)P << std::string(Depth*2+3, ' ') << Msg << " Analyses:";
+ for (unsigned i = 0; i != Set.size(); ++i) {
+ if (i) cerr << ",";
+ cerr << " " << Set[i]->getPassName();
+ }
+ cerr << "\n";
}
}
+#endif
//===----------------------------------------------------------------------===//
// Pass Implementation
//
-void Pass::addToPassManager(PassManagerT<Module> *PM, AnalysisUsage &AU) {
+#ifdef USE_OLD_PASSMANAGER
+void ModulePass::addToPassManager(ModulePassManager *PM, AnalysisUsage &AU) {
PM->addPass(this, AU);
}
+#endif
+
+bool Pass::mustPreserveAnalysisID(const PassInfo *AnalysisID) const {
+#ifdef USE_OLD_PASSMANAGER
+ return Resolver->getAnalysisToUpdate(AnalysisID) != 0;
+#else
+ return Resolver_New->getAnalysisToUpdate(AnalysisID, true) != 0;
+#endif
+}
// dumpPassStructure - Implement the -debug-passes=Structure option
void Pass::dumpPassStructure(unsigned Offset) {
- std::cerr << std::string(Offset*2, ' ') << getPassName() << "\n";
+ cerr << std::string(Offset*2, ' ') << getPassName() << "\n";
}
-// getPassName - Use C++ RTTI to get a SOMEWHAT intelligable name for the pass.
+// getPassName - Use C++ RTTI to get a SOMEWHAT intelligible name for the pass.
//
const char *Pass::getPassName() const {
if (const PassInfo *PI = getPassInfo())
return typeid(*this).name();
}
-// print - Print out the internal state of the pass. This is called by Analyse
-// to print out the contents of an analysis. Otherwise it is not neccesary to
+// print - Print out the internal state of the pass. This is called by Analyze
+// to print out the contents of an analysis. Otherwise it is not necessary to
// implement this method.
//
-void Pass::print(std::ostream &O) const {
+void Pass::print(std::ostream &O,const Module*) const {
O << "Pass::print not implemented for pass: '" << getPassName() << "'!\n";
}
-// dump - call print(std::cerr);
+// dump - call print(cerr);
void Pass::dump() const {
- print(std::cerr, 0);
+ print(*cerr.stream(), 0);
}
+//===----------------------------------------------------------------------===//
+// ImmutablePass Implementation
+//
+#ifdef USE_OLD_PASSMANAGER
+void ImmutablePass::addToPassManager(ModulePassManager *PM,
+ AnalysisUsage &AU) {
+ PM->addPass(this, AU);
+}
+#endif
+
//===----------------------------------------------------------------------===//
// FunctionPass Implementation
//
// run - On a module, we run this pass by initializing, runOnFunction'ing once
// for every function in the module, then by finalizing.
//
-bool FunctionPass::run(Module &M) {
+bool FunctionPass::runOnModule(Module &M) {
bool Changed = doInitialization(M);
-
+
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal()) // Passes are not run on external functions!
Changed |= runOnFunction(*I);
-
+
return Changed | doFinalization(M);
}
bool FunctionPass::run(Function &F) {
if (F.isExternal()) return false;// Passes are not run on external functions!
- return doInitialization(*F.getParent()) | runOnFunction(F)
- | doFinalization(*F.getParent());
+ bool Changed = doInitialization(*F.getParent());
+ Changed |= runOnFunction(F);
+ return Changed | doFinalization(*F.getParent());
}
-void FunctionPass::addToPassManager(PassManagerT<Module> *PM,
+#ifdef USE_OLD_PASSMANAGER
+void FunctionPass::addToPassManager(ModulePassManager *PM,
AnalysisUsage &AU) {
PM->addPass(this, AU);
}
-void FunctionPass::addToPassManager(PassManagerT<Function> *PM,
+void FunctionPass::addToPassManager(FunctionPassManagerT *PM,
AnalysisUsage &AU) {
PM->addPass(this, AU);
}
+#endif
//===----------------------------------------------------------------------===//
// BasicBlockPass Implementation
// function.
//
bool BasicBlockPass::runOnFunction(Function &F) {
- bool Changed = false;
+ bool Changed = doInitialization(F);
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
Changed |= runOnBasicBlock(*I);
- return Changed;
+ return Changed | doFinalization(F);
}
// To run directly on the basic block, we initialize, runOnBasicBlock, then
// finalize.
//
-bool BasicBlockPass::run(BasicBlock &BB) {
- Module &M = *BB.getParent()->getParent();
- return doInitialization(M) | runOnBasicBlock(BB) | doFinalization(M);
+bool BasicBlockPass::runPass(BasicBlock &BB) {
+ Function &F = *BB.getParent();
+ Module &M = *F.getParent();
+ bool Changed = doInitialization(M);
+ Changed |= doInitialization(F);
+ Changed |= runOnBasicBlock(BB);
+ Changed |= doFinalization(F);
+ Changed |= doFinalization(M);
+ return Changed;
}
-void BasicBlockPass::addToPassManager(PassManagerT<Function> *PM,
+#ifdef USE_OLD_PASSMANAGER
+void BasicBlockPass::addToPassManager(FunctionPassManagerT *PM,
AnalysisUsage &AU) {
PM->addPass(this, AU);
}
-void BasicBlockPass::addToPassManager(PassManagerT<BasicBlock> *PM,
+void BasicBlockPass::addToPassManager(BasicBlockPassManager *PM,
AnalysisUsage &AU) {
PM->addPass(this, AU);
}
-
+#endif
//===----------------------------------------------------------------------===//
// Pass Registration mechanism
//
-static std::map<TypeInfo, PassInfo*> *PassInfoMap = 0;
+namespace {
+class PassRegistrar {
+ /// PassInfoMap - Keep track of the passinfo object for each registered llvm
+ /// pass.
+ std::map<TypeInfo, PassInfo*> PassInfoMap;
+
+ /// AnalysisGroupInfo - Keep track of information for each analysis group.
+ struct AnalysisGroupInfo {
+ const PassInfo *DefaultImpl;
+ std::set<const PassInfo *> Implementations;
+ AnalysisGroupInfo() : DefaultImpl(0) {}
+ };
+
+ /// AnalysisGroupInfoMap - Information for each analysis group.
+ std::map<const PassInfo *, AnalysisGroupInfo> AnalysisGroupInfoMap;
+
+public:
+
+ const PassInfo *GetPassInfo(const std::type_info &TI) const {
+ std::map<TypeInfo, PassInfo*>::const_iterator I = PassInfoMap.find(TI);
+ return I != PassInfoMap.end() ? I->second : 0;
+ }
+
+ void RegisterPass(PassInfo &PI) {
+ bool Inserted =
+ PassInfoMap.insert(std::make_pair(TypeInfo(PI.getTypeInfo()),&PI)).second;
+ assert(Inserted && "Pass registered multiple times!");
+ }
+
+ void UnregisterPass(PassInfo &PI) {
+ std::map<TypeInfo, PassInfo*>::iterator I =
+ PassInfoMap.find(PI.getTypeInfo());
+ assert(I != PassInfoMap.end() && "Pass registered but not in map!");
+
+ // Remove pass from the map.
+ PassInfoMap.erase(I);
+ }
+
+ void EnumerateWith(PassRegistrationListener *L) {
+ for (std::map<TypeInfo, PassInfo*>::const_iterator I = PassInfoMap.begin(),
+ E = PassInfoMap.end(); I != E; ++I)
+ L->passEnumerate(I->second);
+ }
+
+
+ /// Analysis Group Mechanisms.
+ void RegisterAnalysisGroup(PassInfo *InterfaceInfo,
+ const PassInfo *ImplementationInfo,
+ bool isDefault) {
+ AnalysisGroupInfo &AGI = AnalysisGroupInfoMap[InterfaceInfo];
+ assert(AGI.Implementations.count(ImplementationInfo) == 0 &&
+ "Cannot add a pass to the same analysis group more than once!");
+ AGI.Implementations.insert(ImplementationInfo);
+ if (isDefault) {
+ assert(AGI.DefaultImpl == 0 && InterfaceInfo->getNormalCtor() == 0 &&
+ "Default implementation for analysis group already specified!");
+ assert(ImplementationInfo->getNormalCtor() &&
+ "Cannot specify pass as default if it does not have a default ctor");
+ AGI.DefaultImpl = ImplementationInfo;
+ InterfaceInfo->setNormalCtor(ImplementationInfo->getNormalCtor());
+ }
+ }
+};
+}
+
+static ManagedStatic<PassRegistrar> PassRegistrarObj;
static std::vector<PassRegistrationListener*> *Listeners = 0;
// getPassInfo - Return the PassInfo data structure that corresponds to this
// pass...
const PassInfo *Pass::getPassInfo() const {
if (PassInfoCache) return PassInfoCache;
- if (PassInfoMap == 0) return 0;
- std::map<TypeInfo, PassInfo*>::iterator I = PassInfoMap->find(typeid(*this));
- return (I != PassInfoMap->end()) ? I->second : 0;
+ return lookupPassInfo(typeid(*this));
}
-void RegisterPassBase::registerPass(PassInfo *PI) {
- if (PassInfoMap == 0)
- PassInfoMap = new std::map<TypeInfo, PassInfo*>();
+const PassInfo *Pass::lookupPassInfo(const std::type_info &TI) {
+ return PassRegistrarObj->GetPassInfo(TI);
+}
- assert(PassInfoMap->find(PI->getTypeInfo()) == PassInfoMap->end() &&
- "Pass already registered!");
- PIObj = PI;
- PassInfoMap->insert(std::make_pair(TypeInfo(PI->getTypeInfo()), PI));
+void RegisterPassBase::registerPass() {
+ PassRegistrarObj->RegisterPass(PIObj);
- // Notify any listeners...
+ // Notify any listeners.
if (Listeners)
for (std::vector<PassRegistrationListener*>::iterator
I = Listeners->begin(), E = Listeners->end(); I != E; ++I)
- (*I)->passRegistered(PI);
+ (*I)->passRegistered(&PIObj);
}
-RegisterPassBase::~RegisterPassBase() {
- assert(PassInfoMap && "Pass registered but not in map!");
- std::map<TypeInfo, PassInfo*>::iterator I =
- PassInfoMap->find(PIObj->getTypeInfo());
- assert(I != PassInfoMap->end() && "Pass registered but not in map!");
-
- // Remove pass from the map...
- PassInfoMap->erase(I);
- if (PassInfoMap->empty()) {
- delete PassInfoMap;
- PassInfoMap = 0;
- }
+void RegisterPassBase::unregisterPass() {
+ PassRegistrarObj->UnregisterPass(PIObj);
+}
- // Notify any listeners...
- if (Listeners)
- for (std::vector<PassRegistrationListener*>::iterator
- I = Listeners->begin(), E = Listeners->end(); I != E; ++I)
- (*I)->passUnregistered(PIObj);
+//===----------------------------------------------------------------------===//
+// Analysis Group Implementation Code
+//===----------------------------------------------------------------------===//
- // Delete the PassInfo object itself...
- delete PIObj;
+// RegisterAGBase implementation
+//
+RegisterAGBase::RegisterAGBase(const std::type_info &Interface,
+ const std::type_info *Pass, bool isDefault)
+ : RegisterPassBase(Interface),
+ ImplementationInfo(0), isDefaultImplementation(isDefault) {
+
+ InterfaceInfo = const_cast<PassInfo*>(Pass::lookupPassInfo(Interface));
+ if (InterfaceInfo == 0) {
+ // First reference to Interface, register it now.
+ registerPass();
+ InterfaceInfo = &PIObj;
+ }
+ assert(PIObj.isAnalysisGroup() &&
+ "Trying to join an analysis group that is a normal pass!");
+
+ if (Pass) {
+ ImplementationInfo = Pass::lookupPassInfo(*Pass);
+ assert(ImplementationInfo &&
+ "Must register pass before adding to AnalysisGroup!");
+
+ // Make sure we keep track of the fact that the implementation implements
+ // the interface.
+ PassInfo *IIPI = const_cast<PassInfo*>(ImplementationInfo);
+ IIPI->addInterfaceImplemented(InterfaceInfo);
+
+ PassRegistrarObj->RegisterAnalysisGroup(InterfaceInfo, IIPI, isDefault);
+ }
}
+void RegisterAGBase::setGroupName(const char *Name) {
+ assert(InterfaceInfo->getPassName()[0] == 0 && "Interface Name already set!");
+ InterfaceInfo->setPassName(Name);
+}
//===----------------------------------------------------------------------===//
// passEnumerate callback on each PassInfo object.
//
void PassRegistrationListener::enumeratePasses() {
- if (PassInfoMap)
- for (std::map<TypeInfo, PassInfo*>::iterator I = PassInfoMap->begin(),
- E = PassInfoMap->end(); I != E; ++I)
- passEnumerate(I->second);
+ PassRegistrarObj->EnumerateWith(this);
+}
+
+//===----------------------------------------------------------------------===//
+// AnalysisUsage Class Implementation
+//
+
+namespace {
+ struct GetCFGOnlyPasses : public PassRegistrationListener {
+ std::vector<AnalysisID> &CFGOnlyList;
+ GetCFGOnlyPasses(std::vector<AnalysisID> &L) : CFGOnlyList(L) {}
+
+ void passEnumerate(const PassInfo *P) {
+ if (P->isCFGOnlyPass())
+ CFGOnlyList.push_back(P);
+ }
+ };
}
+
+// setPreservesCFG - This function should be called to by the pass, iff they do
+// not:
+//
+// 1. Add or remove basic blocks from the function
+// 2. Modify terminator instructions in any way.
+//
+// This function annotates the AnalysisUsage info object to say that analyses
+// that only depend on the CFG are preserved by this pass.
+//
+void AnalysisUsage::setPreservesCFG() {
+ // Since this transformation doesn't modify the CFG, it preserves all analyses
+ // that only depend on the CFG (like dominators, loop info, etc...)
+ GetCFGOnlyPasses(Preserved).enumeratePasses();
+}
+
+
projects / oota-llvm.git / blobdiff