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//===- Bitcode/Writer/ValueEnumerator.h - Number values ---------*- 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 class gives values and types Unique ID's.
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/UniqueVector.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/UseListOrder.h"
#include <cassert>
#include <cstdint>
#include <utility>
#include <vector>
namespace llvm {
class BasicBlock;
class Comdat;
class DIArgList;
class Function;
class Instruction;
class LocalAsMetadata;
class MDNode;
class Metadata;
class Module;
class NamedMDNode;
class raw_ostream;
class Type;
class Value;
class ValueSymbolTable;
class ValueEnumerator {
using TypeList = std::vector<Type *>;
// For each value, we remember its Value* and occurrence frequency.
using ValueList = std::vector<std::pair<const Value *, unsigned>>;
/// Attribute groups as encoded in bitcode are almost AttributeSets, but they
/// include the AttributeList index, so we have to track that in our map.
using IndexAndAttrSet = std::pair<unsigned, AttributeSet>;
UseListOrderStack UseListOrders;
using TypeMapType = DenseMap<Type *, unsigned>;
TypeMapType TypeMap;
TypeList Types;
using ValueMapType = DenseMap<const Value *, unsigned>;
ValueMapType ValueMap;
ValueList Values;
using ComdatSetType = UniqueVector<const Comdat *>;
ComdatSetType Comdats;
std::vector<const Metadata *> MDs;
std::vector<const Metadata *> FunctionMDs;
/// Index of information about a piece of metadata.
struct MDIndex {
unsigned F = 0; ///< The ID of the function for this metadata, if any.
unsigned ID = 0; ///< The implicit ID of this metadata in bitcode.
MDIndex() = default;
explicit MDIndex(unsigned F) : F(F) {}
/// Check if this has a function tag, and it's different from NewF.
bool hasDifferentFunction(unsigned NewF) const { return F && F != NewF; }
/// Fetch the MD this references out of the given metadata array.
const Metadata *get(ArrayRef<const Metadata *> MDs) const {
assert(ID && "Expected non-zero ID");
assert(ID <= MDs.size() && "Expected valid ID");
return MDs[ID - 1];
using MetadataMapType = DenseMap<const Metadata *, MDIndex>;
MetadataMapType MetadataMap;
/// Range of metadata IDs, as a half-open range.
struct MDRange {
unsigned First = 0;
unsigned Last = 0;
/// Number of strings in the prefix of the metadata range.
unsigned NumStrings = 0;
MDRange() = default;
explicit MDRange(unsigned First) : First(First) {}
SmallDenseMap<unsigned, MDRange, 1> FunctionMDInfo;
bool ShouldPreserveUseListOrder;
using AttributeGroupMapType = DenseMap<IndexAndAttrSet, unsigned>;
AttributeGroupMapType AttributeGroupMap;
std::vector<IndexAndAttrSet> AttributeGroups;
using AttributeListMapType = DenseMap<AttributeList, unsigned>;
AttributeListMapType AttributeListMap;
std::vector<AttributeList> AttributeLists;
/// GlobalBasicBlockIDs - This map memoizes the basic block ID's referenced by
/// the "getGlobalBasicBlockID" method.
mutable DenseMap<const BasicBlock*, unsigned> GlobalBasicBlockIDs;
using InstructionMapType = DenseMap<const Instruction *, unsigned>;
InstructionMapType InstructionMap;
unsigned InstructionCount;
/// BasicBlocks - This contains all the basic blocks for the currently
/// incorporated function. Their reverse mapping is stored in ValueMap.
std::vector<const BasicBlock*> BasicBlocks;
/// When a function is incorporated, this is the size of the Values list
/// before incorporation.
unsigned NumModuleValues;
/// When a function is incorporated, this is the size of the Metadatas list
/// before incorporation.
unsigned NumModuleMDs = 0;
unsigned NumMDStrings = 0;
unsigned FirstFuncConstantID;
unsigned FirstInstID;
ValueEnumerator(const Module &M, bool ShouldPreserveUseListOrder);
ValueEnumerator(const ValueEnumerator &) = delete;
ValueEnumerator &operator=(const ValueEnumerator &) = delete;
void dump() const;
void print(raw_ostream &OS, const ValueMapType &Map, const char *Name) const;
void print(raw_ostream &OS, const MetadataMapType &Map,
const char *Name) const;
unsigned getValueID(const Value *V) const;
unsigned getMetadataID(const Metadata *MD) const {
auto ID = getMetadataOrNullID(MD);
assert(ID != 0 && "Metadata not in slotcalculator!");
return ID - 1;
unsigned getMetadataOrNullID(const Metadata *MD) const {
return MetadataMap.lookup(MD).ID;
unsigned numMDs() const { return MDs.size(); }
bool shouldPreserveUseListOrder() const { return ShouldPreserveUseListOrder; }
unsigned getTypeID(Type *T) const {
TypeMapType::const_iterator I = TypeMap.find(T);
assert(I != TypeMap.end() && "Type not in ValueEnumerator!");
return I->second-1;
unsigned getInstructionID(const Instruction *I) const;
void setInstructionID(const Instruction *I);
unsigned getAttributeListID(AttributeList PAL) const {
if (PAL.isEmpty()) return 0; // Null maps to zero.
AttributeListMapType::const_iterator I = AttributeListMap.find(PAL);
assert(I != AttributeListMap.end() && "Attribute not in ValueEnumerator!");
return I->second;
unsigned getAttributeGroupID(IndexAndAttrSet Group) const {
if (!Group.second.hasAttributes())
return 0; // Null maps to zero.
AttributeGroupMapType::const_iterator I = AttributeGroupMap.find(Group);
assert(I != AttributeGroupMap.end() && "Attribute not in ValueEnumerator!");
return I->second;
/// getFunctionConstantRange - Return the range of values that corresponds to
/// function-local constants.
void getFunctionConstantRange(unsigned &Start, unsigned &End) const {
Start = FirstFuncConstantID;
End = FirstInstID;
const ValueList &getValues() const { return Values; }
/// Check whether the current block has any metadata to emit.
bool hasMDs() const { return NumModuleMDs < MDs.size(); }
/// Get the MDString metadata for this block.
ArrayRef<const Metadata *> getMDStrings() const {
return makeArrayRef(MDs).slice(NumModuleMDs, NumMDStrings);
/// Get the non-MDString metadata for this block.
ArrayRef<const Metadata *> getNonMDStrings() const {
return makeArrayRef(MDs).slice(NumModuleMDs).slice(NumMDStrings);
const TypeList &getTypes() const { return Types; }
const std::vector<const BasicBlock*> &getBasicBlocks() const {
return BasicBlocks;
const std::vector<AttributeList> &getAttributeLists() const { return AttributeLists; }
const std::vector<IndexAndAttrSet> &getAttributeGroups() const {
return AttributeGroups;
const ComdatSetType &getComdats() const { return Comdats; }
unsigned getComdatID(const Comdat *C) const;
/// getGlobalBasicBlockID - This returns the function-specific ID for the
/// specified basic block. This is relatively expensive information, so it
/// should only be used by rare constructs such as address-of-label.
unsigned getGlobalBasicBlockID(const BasicBlock *BB) const;
/// incorporateFunction/purgeFunction - If you'd like to deal with a function,
/// use these two methods to get its data into the ValueEnumerator!
void incorporateFunction(const Function &F);
void purgeFunction();
uint64_t computeBitsRequiredForTypeIndicies() const;
void OptimizeConstants(unsigned CstStart, unsigned CstEnd);
/// Reorder the reachable metadata.
/// This is not just an optimization, but is mandatory for emitting MDString
/// correctly.
void organizeMetadata();
/// Drop the function tag from the transitive operands of the given node.
void dropFunctionFromMetadata(MetadataMapType::value_type &FirstMD);
/// Incorporate the function metadata.
/// This should be called before enumerating LocalAsMetadata for the
/// function.
void incorporateFunctionMetadata(const Function &F);
/// Enumerate a single instance of metadata with the given function tag.
/// If \c MD has already been enumerated, check that \c F matches its
/// function tag. If not, call \a dropFunctionFromMetadata().
/// Otherwise, mark \c MD as visited. Assign it an ID, or just return it if
/// it's an \a MDNode.
const MDNode *enumerateMetadataImpl(unsigned F, const Metadata *MD);
unsigned getMetadataFunctionID(const Function *F) const;
/// Enumerate reachable metadata in (almost) post-order.
/// Enumerate all the metadata reachable from MD. We want to minimize the
/// cost of reading bitcode records, and so the primary consideration is that
/// operands of uniqued nodes are resolved before the nodes are read. This
/// avoids re-uniquing them on the context and factors away RAUW support.
/// This algorithm guarantees that subgraphs of uniqued nodes are in
/// post-order. Distinct subgraphs reachable only from a single uniqued node
/// will be in post-order.
/// \note The relative order of a distinct and uniqued node is irrelevant.
/// \a organizeMetadata() will later partition distinct nodes ahead of
/// uniqued ones.
void EnumerateMetadata(const Function *F, const Metadata *MD);
void EnumerateMetadata(unsigned F, const Metadata *MD);
void EnumerateFunctionLocalMetadata(const Function &F,
const LocalAsMetadata *Local);
void EnumerateFunctionLocalMetadata(unsigned F, const LocalAsMetadata *Local);
void EnumerateFunctionLocalListMetadata(const Function &F,
const DIArgList *ArgList);
void EnumerateFunctionLocalListMetadata(unsigned F, const DIArgList *Arglist);
void EnumerateNamedMDNode(const NamedMDNode *NMD);
void EnumerateValue(const Value *V);
void EnumerateType(Type *T);
void EnumerateOperandType(const Value *V);
void EnumerateAttributes(AttributeList PAL);
void EnumerateValueSymbolTable(const ValueSymbolTable &ST);
void EnumerateNamedMetadata(const Module &M);
} // end namespace llvm