diff options
| author | Stephen Hines <srhines@google.com> | 2019-07-02 16:25:20 -0700 |
|---|---|---|
| committer | Ali B <abittin@gmail.com> | 2019-07-05 19:33:16 +0300 |
| commit | 9afee4e65dc5f9f5eb371683729ff67b8df81d03 (patch) | |
| tree | 4cf241d6c9044f91ee8c06e6920174d06f8de0b6 /clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h | |
| parent | 2f19bd722c4c825320d1511c1ed83161b7f95d51 (diff) | |
clang 9.0.5 (based on r353983e) from build 5696680.
Bug: http://b/135931688
Bug: http://b/136008926
Test: N/A
Change-Id: I922d17410047d2e2df4625615352c588ee71b203
Diffstat (limited to 'clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h')
| -rw-r--r-- | clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h b/clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h new file mode 100644 index 00000000..1952a210 --- /dev/null +++ b/clang-r353983e/include/llvm/Transforms/Utils/ValueMapper.h @@ -0,0 +1,280 @@ +//===- ValueMapper.h - Remapping for constants and metadata -----*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines the MapValue interface which is used by various parts of +// the Transforms/Utils library to implement cloning and linking facilities. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H +#define LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H + +#include "llvm/ADT/ArrayRef.h" +#include "llvm/IR/ValueHandle.h" +#include "llvm/IR/ValueMap.h" + +namespace llvm { + +class Constant; +class Function; +class GlobalAlias; +class GlobalVariable; +class Instruction; +class MDNode; +class Metadata; +class Type; +class Value; + +using ValueToValueMapTy = ValueMap<const Value *, WeakTrackingVH>; + +/// This is a class that can be implemented by clients to remap types when +/// cloning constants and instructions. +class ValueMapTypeRemapper { + virtual void anchor(); // Out of line method. + +public: + virtual ~ValueMapTypeRemapper() = default; + + /// The client should implement this method if they want to remap types while + /// mapping values. + virtual Type *remapType(Type *SrcTy) = 0; +}; + +/// This is a class that can be implemented by clients to materialize Values on +/// demand. +class ValueMaterializer { + virtual void anchor(); // Out of line method. + +protected: + ValueMaterializer() = default; + ValueMaterializer(const ValueMaterializer &) = default; + ValueMaterializer &operator=(const ValueMaterializer &) = default; + ~ValueMaterializer() = default; + +public: + /// This method can be implemented to generate a mapped Value on demand. For + /// example, if linking lazily. Returns null if the value is not materialized. + virtual Value *materialize(Value *V) = 0; +}; + +/// These are flags that the value mapping APIs allow. +enum RemapFlags { + RF_None = 0, + + /// If this flag is set, the remapper knows that only local values within a + /// function (such as an instruction or argument) are mapped, not global + /// values like functions and global metadata. + RF_NoModuleLevelChanges = 1, + + /// If this flag is set, the remapper ignores missing function-local entries + /// (Argument, Instruction, BasicBlock) that are not in the value map. If it + /// is unset, it aborts if an operand is asked to be remapped which doesn't + /// exist in the mapping. + /// + /// There are no such assertions in MapValue(), whose results are almost + /// unchanged by this flag. This flag mainly changes the assertion behaviour + /// in RemapInstruction(). + /// + /// Since an Instruction's metadata operands (even that point to SSA values) + /// aren't guaranteed to be dominated by their definitions, MapMetadata will + /// return "!{}" instead of "null" for \a LocalAsMetadata instances whose SSA + /// values are unmapped when this flag is set. Otherwise, \a MapValue() + /// completely ignores this flag. + /// + /// \a MapMetadata() always ignores this flag. + RF_IgnoreMissingLocals = 2, + + /// Instruct the remapper to move distinct metadata instead of duplicating it + /// when there are module-level changes. + RF_MoveDistinctMDs = 4, + + /// Any global values not in value map are mapped to null instead of mapping + /// to self. Illegal if RF_IgnoreMissingLocals is also set. + RF_NullMapMissingGlobalValues = 8, +}; + +inline RemapFlags operator|(RemapFlags LHS, RemapFlags RHS) { + return RemapFlags(unsigned(LHS) | unsigned(RHS)); +} + +/// Context for (re-)mapping values (and metadata). +/// +/// A shared context used for mapping and remapping of Value and Metadata +/// instances using \a ValueToValueMapTy, \a RemapFlags, \a +/// ValueMapTypeRemapper, and \a ValueMaterializer. +/// +/// There are a number of top-level entry points: +/// - \a mapValue() (and \a mapConstant()); +/// - \a mapMetadata() (and \a mapMDNode()); +/// - \a remapInstruction(); and +/// - \a remapFunction(). +/// +/// The \a ValueMaterializer can be used as a callback, but cannot invoke any +/// of these top-level functions recursively. Instead, callbacks should use +/// one of the following to schedule work lazily in the \a ValueMapper +/// instance: +/// - \a scheduleMapGlobalInitializer() +/// - \a scheduleMapAppendingVariable() +/// - \a scheduleMapGlobalAliasee() +/// - \a scheduleRemapFunction() +/// +/// Sometimes a callback needs a different mapping context. Such a context can +/// be registered using \a registerAlternateMappingContext(), which takes an +/// alternate \a ValueToValueMapTy and \a ValueMaterializer and returns a ID to +/// pass into the schedule*() functions. +/// +/// TODO: lib/Linker really doesn't need the \a ValueHandle in the \a +/// ValueToValueMapTy. We should template \a ValueMapper (and its +/// implementation classes), and explicitly instantiate on two concrete +/// instances of \a ValueMap (one as \a ValueToValueMap, and one with raw \a +/// Value pointers). It may be viable to do away with \a TrackingMDRef in the +/// \a Metadata side map for the lib/Linker case as well, in which case we'll +/// need a new template parameter on \a ValueMap. +/// +/// TODO: Update callers of \a RemapInstruction() and \a MapValue() (etc.) to +/// use \a ValueMapper directly. +class ValueMapper { + void *pImpl; + +public: + ValueMapper(ValueToValueMapTy &VM, RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr); + ValueMapper(ValueMapper &&) = delete; + ValueMapper(const ValueMapper &) = delete; + ValueMapper &operator=(ValueMapper &&) = delete; + ValueMapper &operator=(const ValueMapper &) = delete; + ~ValueMapper(); + + /// Register an alternate mapping context. + /// + /// Returns a MappingContextID that can be used with the various schedule*() + /// API to switch in a different value map on-the-fly. + unsigned + registerAlternateMappingContext(ValueToValueMapTy &VM, + ValueMaterializer *Materializer = nullptr); + + /// Add to the current \a RemapFlags. + /// + /// \note Like the top-level mapping functions, \a addFlags() must be called + /// at the top level, not during a callback in a \a ValueMaterializer. + void addFlags(RemapFlags Flags); + + Metadata *mapMetadata(const Metadata &MD); + MDNode *mapMDNode(const MDNode &N); + + Value *mapValue(const Value &V); + Constant *mapConstant(const Constant &C); + + void remapInstruction(Instruction &I); + void remapFunction(Function &F); + + void scheduleMapGlobalInitializer(GlobalVariable &GV, Constant &Init, + unsigned MappingContextID = 0); + void scheduleMapAppendingVariable(GlobalVariable &GV, Constant *InitPrefix, + bool IsOldCtorDtor, + ArrayRef<Constant *> NewMembers, + unsigned MappingContextID = 0); + void scheduleMapGlobalAliasee(GlobalAlias &GA, Constant &Aliasee, + unsigned MappingContextID = 0); + void scheduleRemapFunction(Function &F, unsigned MappingContextID = 0); +}; + +/// Look up or compute a value in the value map. +/// +/// Return a mapped value for a function-local value (Argument, Instruction, +/// BasicBlock), or compute and memoize a value for a Constant. +/// +/// 1. If \c V is in VM, return the result. +/// 2. Else if \c V can be materialized with \c Materializer, do so, memoize +/// it in \c VM, and return it. +/// 3. Else if \c V is a function-local value, return nullptr. +/// 4. Else if \c V is a \a GlobalValue, return \c nullptr or \c V depending +/// on \a RF_NullMapMissingGlobalValues. +/// 5. Else if \c V is a \a MetadataAsValue wrapping a LocalAsMetadata, +/// recurse on the local SSA value, and return nullptr or "metadata !{}" on +/// missing depending on RF_IgnoreMissingValues. +/// 6. Else if \c V is a \a MetadataAsValue, rewrap the return of \a +/// MapMetadata(). +/// 7. Else, compute the equivalent constant, and return it. +inline Value *MapValue(const Value *V, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + return ValueMapper(VM, Flags, TypeMapper, Materializer).mapValue(*V); +} + +/// Lookup or compute a mapping for a piece of metadata. +/// +/// Compute and memoize a mapping for \c MD. +/// +/// 1. If \c MD is mapped, return it. +/// 2. Else if \a RF_NoModuleLevelChanges or \c MD is an \a MDString, return +/// \c MD. +/// 3. Else if \c MD is a \a ConstantAsMetadata, call \a MapValue() and +/// re-wrap its return (returning nullptr on nullptr). +/// 4. Else, \c MD is an \a MDNode. These are remapped, along with their +/// transitive operands. Distinct nodes are duplicated or moved depending +/// on \a RF_MoveDistinctNodes. Uniqued nodes are remapped like constants. +/// +/// \note \a LocalAsMetadata is completely unsupported by \a MapMetadata. +/// Instead, use \a MapValue() with its wrapping \a MetadataAsValue instance. +inline Metadata *MapMetadata(const Metadata *MD, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + return ValueMapper(VM, Flags, TypeMapper, Materializer).mapMetadata(*MD); +} + +/// Version of MapMetadata with type safety for MDNode. +inline MDNode *MapMetadata(const MDNode *MD, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + return ValueMapper(VM, Flags, TypeMapper, Materializer).mapMDNode(*MD); +} + +/// Convert the instruction operands from referencing the current values into +/// those specified by VM. +/// +/// If \a RF_IgnoreMissingLocals is set and an operand can't be found via \a +/// MapValue(), use the old value. Otherwise assert that this doesn't happen. +/// +/// Note that \a MapValue() only returns \c nullptr for SSA values missing from +/// \c VM. +inline void RemapInstruction(Instruction *I, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + ValueMapper(VM, Flags, TypeMapper, Materializer).remapInstruction(*I); +} + +/// Remap the operands, metadata, arguments, and instructions of a function. +/// +/// Calls \a MapValue() on prefix data, prologue data, and personality +/// function; calls \a MapMetadata() on each attached MDNode; remaps the +/// argument types using the provided \c TypeMapper; and calls \a +/// RemapInstruction() on every instruction. +inline void RemapFunction(Function &F, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + ValueMapper(VM, Flags, TypeMapper, Materializer).remapFunction(F); +} + +/// Version of MapValue with type safety for Constant. +inline Constant *MapValue(const Constant *V, ValueToValueMapTy &VM, + RemapFlags Flags = RF_None, + ValueMapTypeRemapper *TypeMapper = nullptr, + ValueMaterializer *Materializer = nullptr) { + return ValueMapper(VM, Flags, TypeMapper, Materializer).mapConstant(*V); +} + +} // end namespace llvm + +#endif // LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H |
