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//===- LegacyPassManagers.h - Legacy Pass Infrastructure --------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file declares the LLVM Pass Manager infrastructure.
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Pass.h"
#include <vector>
// Overview:
// The Pass Manager Infrastructure manages passes. It's responsibilities are:
// o Manage optimization pass execution order
// o Make required Analysis information available before pass P is run
// o Release memory occupied by dead passes
// o If Analysis information is dirtied by a pass then regenerate Analysis
// information before it is consumed by another pass.
// Pass Manager Infrastructure uses multiple pass managers. They are
// PassManager, FunctionPassManager, MPPassManager, FPPassManager, BBPassManager.
// This class hierarchy uses multiple inheritance but pass managers do not
// derive from another pass manager.
// PassManager and FunctionPassManager are two top-level pass manager that
// represents the external interface of this entire pass manager infrastucture.
// Important classes :
// [o] class PMTopLevelManager;
// Two top level managers, PassManager and FunctionPassManager, derive from
// PMTopLevelManager. PMTopLevelManager manages information used by top level
// managers such as last user info.
// [o] class PMDataManager;
// PMDataManager manages information, e.g. list of available analysis info,
// used by a pass manager to manage execution order of passes. It also provides
// a place to implement common pass manager APIs. All pass managers derive from
// PMDataManager.
// [o] class FunctionPassManager;
// This is a external interface used to manage FunctionPasses. This
// interface relies on FunctionPassManagerImpl to do all the tasks.
// [o] class FunctionPassManagerImpl : public ModulePass, PMDataManager,
// public PMTopLevelManager;
// FunctionPassManagerImpl is a top level manager. It manages FPPassManagers
// [o] class FPPassManager : public ModulePass, public PMDataManager;
// FPPassManager manages FunctionPasses and BBPassManagers
// [o] class MPPassManager : public Pass, public PMDataManager;
// MPPassManager manages ModulePasses and FPPassManagers
// [o] class PassManager;
// This is a external interface used by various tools to manages passes. It
// relies on PassManagerImpl to do all the tasks.
// [o] class PassManagerImpl : public Pass, public PMDataManager,
// public PMTopLevelManager
// PassManagerImpl is a top level pass manager responsible for managing
// MPPassManagers.
#include "llvm/Support/PrettyStackTrace.h"
namespace llvm {
template <typename T> class ArrayRef;
class Module;
class Pass;
class StringRef;
class Value;
class Timer;
class PMDataManager;
// enums for debugging strings
enum PassDebuggingString {
EXECUTION_MSG, // "Executing Pass '" + PassName
MODIFICATION_MSG, // "Made Modification '" + PassName
FREEING_MSG, // " Freeing Pass '" + PassName
ON_FUNCTION_MSG, // "' on Function '" + FunctionName + "'...\n"
ON_MODULE_MSG, // "' on Module '" + ModuleName + "'...\n"
ON_REGION_MSG, // "' on Region '" + Msg + "'...\n'"
ON_LOOP_MSG, // "' on Loop '" + Msg + "'...\n'"
ON_CG_MSG // "' on Call Graph Nodes '" + Msg + "'...\n'"
/// PassManagerPrettyStackEntry - This is used to print informative information
/// about what pass is running when/if a stack trace is generated.
class PassManagerPrettyStackEntry : public PrettyStackTraceEntry {
Pass *P;
Value *V;
Module *M;
explicit PassManagerPrettyStackEntry(Pass *p)
: P(p), V(nullptr), M(nullptr) {} // When P is releaseMemory'd.
PassManagerPrettyStackEntry(Pass *p, Value &v)
: P(p), V(&v), M(nullptr) {} // When P is run on V
PassManagerPrettyStackEntry(Pass *p, Module &m)
: P(p), V(nullptr), M(&m) {} // When P is run on M
/// print - Emit information about this stack frame to OS.
void print(raw_ostream &OS) const override;
// PMStack
/// PMStack - This class implements a stack data structure of PMDataManager
/// pointers.
/// Top level pass managers (see PassManager.cpp) maintain active Pass Managers
/// using PMStack. Each Pass implements assignPassManager() to connect itself
/// with appropriate manager. assignPassManager() walks PMStack to find
/// suitable manager.
class PMStack {
typedef std::vector<PMDataManager *>::const_reverse_iterator iterator;
iterator begin() const { return S.rbegin(); }
iterator end() const { return S.rend(); }
void pop();
PMDataManager *top() const { return S.back(); }
void push(PMDataManager *PM);
bool empty() const { return S.empty(); }
void dump() const;
std::vector<PMDataManager *> S;
// PMTopLevelManager
/// PMTopLevelManager manages LastUser info and collects common APIs used by
/// top level pass managers.
class PMTopLevelManager {
explicit PMTopLevelManager(PMDataManager *PMDM);
unsigned getNumContainedManagers() const {
return (unsigned)PassManagers.size();
void initializeAllAnalysisInfo();
virtual PMDataManager *getAsPMDataManager() = 0;
virtual PassManagerType getTopLevelPassManagerType() = 0;
/// Schedule pass P for execution. Make sure that passes required by
/// P are run before P is run. Update analysis info maintained by
/// the manager. Remove dead passes. This is a recursive function.
void schedulePass(Pass *P);
/// Set pass P as the last user of the given analysis passes.
void setLastUser(ArrayRef<Pass*> AnalysisPasses, Pass *P);
/// Collect passes whose last user is P
void collectLastUses(SmallVectorImpl<Pass *> &LastUses, Pass *P);
/// Find the pass that implements Analysis AID. Search immutable
/// passes and all pass managers. If desired pass is not found
/// then return NULL.
Pass *findAnalysisPass(AnalysisID AID);
/// Retrieve the PassInfo for an analysis.
const PassInfo *findAnalysisPassInfo(AnalysisID AID) const;
/// Find analysis usage information for the pass P.
AnalysisUsage *findAnalysisUsage(Pass *P);
virtual ~PMTopLevelManager();
/// Add immutable pass and initialize it.
void addImmutablePass(ImmutablePass *P);
inline SmallVectorImpl<ImmutablePass *>& getImmutablePasses() {
return ImmutablePasses;
void addPassManager(PMDataManager *Manager) {
// Add Manager into the list of managers that are not directly
// maintained by this top level pass manager
inline void addIndirectPassManager(PMDataManager *Manager) {
// Print passes managed by this top level manager.
void dumpPasses() const;
void dumpArguments() const;
// Active Pass Managers
PMStack activeStack;
/// Collection of pass managers
SmallVector<PMDataManager *, 8> PassManagers;
/// Collection of pass managers that are not directly maintained
/// by this pass manager
SmallVector<PMDataManager *, 8> IndirectPassManagers;
// Map to keep track of last user of the analysis pass.
// LastUser->second is the last user of Lastuser->first.
DenseMap<Pass *, Pass *> LastUser;
// Map to keep track of passes that are last used by a pass.
// This inverse map is initialized at PM->run() based on
// LastUser map.
DenseMap<Pass *, SmallPtrSet<Pass *, 8> > InversedLastUser;
/// Immutable passes are managed by top level manager.
SmallVector<ImmutablePass *, 16> ImmutablePasses;
/// Map from ID to immutable passes.
SmallDenseMap<AnalysisID, ImmutablePass *, 8> ImmutablePassMap;
/// A wrapper around AnalysisUsage for the purpose of uniqueing. The wrapper
/// is used to avoid needing to make AnalysisUsage itself a folding set node.
struct AUFoldingSetNode : public FoldingSetNode {
AnalysisUsage AU;
AUFoldingSetNode(const AnalysisUsage &AU) : AU(AU) {}
void Profile(FoldingSetNodeID &ID) const {
Profile(ID, AU);
static void Profile(FoldingSetNodeID &ID, const AnalysisUsage &AU) {
// TODO: We could consider sorting the dependency arrays within the
// AnalysisUsage (since they are conceptually unordered).
auto ProfileVec = [&](const SmallVectorImpl<AnalysisID>& Vec) {
for(AnalysisID AID : Vec)
// Contains all of the unique combinations of AnalysisUsage. This is helpful
// when we have multiple instances of the same pass since they'll usually
// have the same analysis usage and can share storage.
FoldingSet<AUFoldingSetNode> UniqueAnalysisUsages;
// Allocator used for allocating UAFoldingSetNodes. This handles deletion of
// all allocated nodes in one fell swoop.
SpecificBumpPtrAllocator<AUFoldingSetNode> AUFoldingSetNodeAllocator;
// Maps from a pass to it's associated entry in UniqueAnalysisUsages. Does
// not own the storage associated with either key or value..
DenseMap<Pass *, AnalysisUsage*> AnUsageMap;
/// Collection of PassInfo objects found via analysis IDs and in this top
/// level manager. This is used to memoize queries to the pass registry.
/// FIXME: This is an egregious hack because querying the pass registry is
/// either slow or racy.
mutable DenseMap<AnalysisID, const PassInfo *> AnalysisPassInfos;
// PMDataManager
/// PMDataManager provides the common place to manage the analysis data
/// used by pass managers.
class PMDataManager {
explicit PMDataManager() : TPM(nullptr), Depth(0) {
virtual ~PMDataManager();
virtual Pass *getAsPass() = 0;
/// Augment AvailableAnalysis by adding analysis made available by pass P.
void recordAvailableAnalysis(Pass *P);
/// verifyPreservedAnalysis -- Verify analysis presreved by pass P.
void verifyPreservedAnalysis(Pass *P);
/// Remove Analysis that is not preserved by the pass
void removeNotPreservedAnalysis(Pass *P);
/// Remove dead passes used by P.
void removeDeadPasses(Pass *P, StringRef Msg,
enum PassDebuggingString);
/// Remove P.
void freePass(Pass *P, StringRef Msg,
enum PassDebuggingString);
/// Add pass P into the PassVector. Update
/// AvailableAnalysis appropriately if ProcessAnalysis is true.
void add(Pass *P, bool ProcessAnalysis = true);
/// Add RequiredPass into list of lower level passes required by pass P.
/// RequiredPass is run on the fly by Pass Manager when P requests it
/// through getAnalysis interface.
virtual void addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass);
virtual Pass *getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F);
/// Initialize available analysis information.
void initializeAnalysisInfo() {
for (unsigned i = 0; i < PMT_Last; ++i)
InheritedAnalysis[i] = nullptr;
// Return true if P preserves high level analysis used by other
// passes that are managed by this manager.
bool preserveHigherLevelAnalysis(Pass *P);
/// Populate UsedPasses with analysis pass that are used or required by pass
/// P and are available. Populate ReqPassNotAvailable with analysis pass that
/// are required by pass P but are not available.
void collectRequiredAndUsedAnalyses(
SmallVectorImpl<Pass *> &UsedPasses,
SmallVectorImpl<AnalysisID> &ReqPassNotAvailable, Pass *P);
/// All Required analyses should be available to the pass as it runs! Here
/// we fill in the AnalysisImpls member of the pass so that it can
/// successfully use the getAnalysis() method to retrieve the
/// implementations it needs.
void initializeAnalysisImpl(Pass *P);
/// Find the pass that implements Analysis AID. If desired pass is not found
/// then return NULL.
Pass *findAnalysisPass(AnalysisID AID, bool Direction);
// Access toplevel manager
PMTopLevelManager *getTopLevelManager() { return TPM; }
void setTopLevelManager(PMTopLevelManager *T) { TPM = T; }
unsigned getDepth() const { return Depth; }
void setDepth(unsigned newDepth) { Depth = newDepth; }
// Print routines used by debug-pass
void dumpLastUses(Pass *P, unsigned Offset) const;
void dumpPassArguments() const;
void dumpPassInfo(Pass *P, enum PassDebuggingString S1,
enum PassDebuggingString S2, StringRef Msg);
void dumpRequiredSet(const Pass *P) const;
void dumpPreservedSet(const Pass *P) const;
void dumpUsedSet(const Pass *P) const;
unsigned getNumContainedPasses() const {
return (unsigned)PassVector.size();
virtual PassManagerType getPassManagerType() const {
assert ( 0 && "Invalid use of getPassManagerType");
return PMT_Unknown;
DenseMap<AnalysisID, Pass*> *getAvailableAnalysis() {
return &AvailableAnalysis;
// Collect AvailableAnalysis from all the active Pass Managers.
void populateInheritedAnalysis(PMStack &PMS) {
unsigned Index = 0;
for (PMStack::iterator I = PMS.begin(), E = PMS.end();
I != E; ++I)
InheritedAnalysis[Index++] = (*I)->getAvailableAnalysis();
/// Set the initial size of the module if the user has specified that they
/// want remarks for size.
/// Returns 0 if the remark was not requested.
unsigned initSizeRemarkInfo(
Module &M,
StringMap<std::pair<unsigned, unsigned>> &FunctionToInstrCount);
/// Emit a remark signifying that the number of IR instructions in the module
/// changed.
/// \p F is optionally passed by passes which run on Functions, and thus
/// always know whether or not a non-empty function is available.
/// \p FunctionToInstrCount maps the name of a \p Function to a pair. The
/// first member of the pair is the IR count of the \p Function before running
/// \p P, and the second member is the IR count of the \p Function after
/// running \p P.
void emitInstrCountChangedRemark(
Pass *P, Module &M, int64_t Delta, unsigned CountBefore,
StringMap<std::pair<unsigned, unsigned>> &FunctionToInstrCount,
Function *F = nullptr);
// Top level manager.
PMTopLevelManager *TPM;
// Collection of pass that are managed by this manager
SmallVector<Pass *, 16> PassVector;
// Collection of Analysis provided by Parent pass manager and
// used by current pass manager. At at time there can not be more
// then PMT_Last active pass mangers.
DenseMap<AnalysisID, Pass *> *InheritedAnalysis[PMT_Last];
/// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
/// or higher is specified.
bool isPassDebuggingExecutionsOrMore() const;
void dumpAnalysisUsage(StringRef Msg, const Pass *P,
const AnalysisUsage::VectorType &Set) const;
// Set of available Analysis. This information is used while scheduling
// pass. If a pass requires an analysis which is not available then
// the required analysis pass is scheduled to run before the pass itself is
// scheduled to run.
DenseMap<AnalysisID, Pass*> AvailableAnalysis;
// Collection of higher level analysis used by the pass managed by
// this manager.
SmallVector<Pass *, 16> HigherLevelAnalysis;
unsigned Depth;
// FPPassManager
/// FPPassManager manages BBPassManagers and FunctionPasses.
/// It batches all function passes and basic block pass managers together and
/// sequence them to process one function at a time before processing next
/// function.
class FPPassManager : public ModulePass, public PMDataManager {
static char ID;
explicit FPPassManager()
: ModulePass(ID), PMDataManager() { }
/// run - Execute all of the passes scheduled for execution. Keep track of
/// whether any of the passes modifies the module, and if so, return true.
bool runOnFunction(Function &F);
bool runOnModule(Module &M) override;
/// cleanup - After running all passes, clean up pass manager cache.
void cleanup();
/// doInitialization - Overrides ModulePass doInitialization for global
/// initialization tasks
using ModulePass::doInitialization;
/// doInitialization - Run all of the initializers for the function passes.
bool doInitialization(Module &M) override;
/// doFinalization - Overrides ModulePass doFinalization for global
/// finalization tasks
using ModulePass::doFinalization;
/// doFinalization - Run all of the finalizers for the function passes.
bool doFinalization(Module &M) override;
PMDataManager *getAsPMDataManager() override { return this; }
Pass *getAsPass() override { return this; }
/// Pass Manager itself does not invalidate any analysis info.
void getAnalysisUsage(AnalysisUsage &Info) const override {
// Print passes managed by this manager
void dumpPassStructure(unsigned Offset) override;
StringRef getPassName() const override { return "Function Pass Manager"; }
FunctionPass *getContainedPass(unsigned N) {
assert ( N < PassVector.size() && "Pass number out of range!");
FunctionPass *FP = static_cast<FunctionPass *>(PassVector[N]);
return FP;
PassManagerType getPassManagerType() const override {
return PMT_FunctionPassManager;