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[NFC][PassManager] Remove PreservedAnalysesT template parameter (llvm…
…#80324) This is always PreservedAnalyses. Perhaps in the past there was the idea to make some types of passes return more invalidation information, but that hasn't happened. Requires splitting out some analysis classes into a header so PassManagerInternal.h can see the definition of PreservedAnalyses.
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//===- Analysis.h --------------------------------------------*- 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 | ||
// | ||
//===----------------------------------------------------------------------===// | ||
/// \file | ||
/// Pass manager infrastructure for declaring and invalidating analyses. | ||
//===----------------------------------------------------------------------===// | ||
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#ifndef LLVM_IR_ANALYSIS_H | ||
#define LLVM_IR_ANALYSIS_H | ||
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#include "llvm/ADT/SmallPtrSet.h" | ||
#include "llvm/IR/Function.h" | ||
#include "llvm/IR/Module.h" | ||
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namespace llvm { | ||
/// A special type used by analysis passes to provide an address that | ||
/// identifies that particular analysis pass type. | ||
/// | ||
/// Analysis passes should have a static data member of this type and derive | ||
/// from the \c AnalysisInfoMixin to get a static ID method used to identify | ||
/// the analysis in the pass management infrastructure. | ||
struct alignas(8) AnalysisKey {}; | ||
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/// A special type used to provide an address that identifies a set of related | ||
/// analyses. These sets are primarily used below to mark sets of analyses as | ||
/// preserved. | ||
/// | ||
/// For example, a transformation can indicate that it preserves the CFG of a | ||
/// function by preserving the appropriate AnalysisSetKey. An analysis that | ||
/// depends only on the CFG can then check if that AnalysisSetKey is preserved; | ||
/// if it is, the analysis knows that it itself is preserved. | ||
struct alignas(8) AnalysisSetKey {}; | ||
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/// This templated class represents "all analyses that operate over \<a | ||
/// particular IR unit\>" (e.g. a Function or a Module) in instances of | ||
/// PreservedAnalysis. | ||
/// | ||
/// This lets a transformation say e.g. "I preserved all function analyses". | ||
/// | ||
/// Note that you must provide an explicit instantiation declaration and | ||
/// definition for this template in order to get the correct behavior on | ||
/// Windows. Otherwise, the address of SetKey will not be stable. | ||
template <typename IRUnitT> class AllAnalysesOn { | ||
public: | ||
static AnalysisSetKey *ID() { return &SetKey; } | ||
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private: | ||
static AnalysisSetKey SetKey; | ||
}; | ||
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template <typename IRUnitT> AnalysisSetKey AllAnalysesOn<IRUnitT>::SetKey; | ||
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extern template class AllAnalysesOn<Module>; | ||
extern template class AllAnalysesOn<Function>; | ||
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/// Represents analyses that only rely on functions' control flow. | ||
/// | ||
/// This can be used with \c PreservedAnalyses to mark the CFG as preserved and | ||
/// to query whether it has been preserved. | ||
/// | ||
/// The CFG of a function is defined as the set of basic blocks and the edges | ||
/// between them. Changing the set of basic blocks in a function is enough to | ||
/// mutate the CFG. Mutating the condition of a branch or argument of an | ||
/// invoked function does not mutate the CFG, but changing the successor labels | ||
/// of those instructions does. | ||
class CFGAnalyses { | ||
public: | ||
static AnalysisSetKey *ID() { return &SetKey; } | ||
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private: | ||
static AnalysisSetKey SetKey; | ||
}; | ||
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/// A set of analyses that are preserved following a run of a transformation | ||
/// pass. | ||
/// | ||
/// Transformation passes build and return these objects to communicate which | ||
/// analyses are still valid after the transformation. For most passes this is | ||
/// fairly simple: if they don't change anything all analyses are preserved, | ||
/// otherwise only a short list of analyses that have been explicitly updated | ||
/// are preserved. | ||
/// | ||
/// This class also lets transformation passes mark abstract *sets* of analyses | ||
/// as preserved. A transformation that (say) does not alter the CFG can | ||
/// indicate such by marking a particular AnalysisSetKey as preserved, and | ||
/// then analyses can query whether that AnalysisSetKey is preserved. | ||
/// | ||
/// Finally, this class can represent an "abandoned" analysis, which is | ||
/// not preserved even if it would be covered by some abstract set of analyses. | ||
/// | ||
/// Given a `PreservedAnalyses` object, an analysis will typically want to | ||
/// figure out whether it is preserved. In the example below, MyAnalysisType is | ||
/// preserved if it's not abandoned, and (a) it's explicitly marked as | ||
/// preserved, (b), the set AllAnalysesOn<MyIRUnit> is preserved, or (c) both | ||
/// AnalysisSetA and AnalysisSetB are preserved. | ||
/// | ||
/// ``` | ||
/// auto PAC = PA.getChecker<MyAnalysisType>(); | ||
/// if (PAC.preserved() || PAC.preservedSet<AllAnalysesOn<MyIRUnit>>() || | ||
/// (PAC.preservedSet<AnalysisSetA>() && | ||
/// PAC.preservedSet<AnalysisSetB>())) { | ||
/// // The analysis has been successfully preserved ... | ||
/// } | ||
/// ``` | ||
class PreservedAnalyses { | ||
public: | ||
/// Convenience factory function for the empty preserved set. | ||
static PreservedAnalyses none() { return PreservedAnalyses(); } | ||
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/// Construct a special preserved set that preserves all passes. | ||
static PreservedAnalyses all() { | ||
PreservedAnalyses PA; | ||
PA.PreservedIDs.insert(&AllAnalysesKey); | ||
return PA; | ||
} | ||
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/// Construct a preserved analyses object with a single preserved set. | ||
template <typename AnalysisSetT> static PreservedAnalyses allInSet() { | ||
PreservedAnalyses PA; | ||
PA.preserveSet<AnalysisSetT>(); | ||
return PA; | ||
} | ||
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/// Mark an analysis as preserved. | ||
template <typename AnalysisT> void preserve() { preserve(AnalysisT::ID()); } | ||
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/// Given an analysis's ID, mark the analysis as preserved, adding it | ||
/// to the set. | ||
void preserve(AnalysisKey *ID) { | ||
// Clear this ID from the explicit not-preserved set if present. | ||
NotPreservedAnalysisIDs.erase(ID); | ||
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// If we're not already preserving all analyses (other than those in | ||
// NotPreservedAnalysisIDs). | ||
if (!areAllPreserved()) | ||
PreservedIDs.insert(ID); | ||
} | ||
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/// Mark an analysis set as preserved. | ||
template <typename AnalysisSetT> void preserveSet() { | ||
preserveSet(AnalysisSetT::ID()); | ||
} | ||
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/// Mark an analysis set as preserved using its ID. | ||
void preserveSet(AnalysisSetKey *ID) { | ||
// If we're not already in the saturated 'all' state, add this set. | ||
if (!areAllPreserved()) | ||
PreservedIDs.insert(ID); | ||
} | ||
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/// Mark an analysis as abandoned. | ||
/// | ||
/// An abandoned analysis is not preserved, even if it is nominally covered | ||
/// by some other set or was previously explicitly marked as preserved. | ||
/// | ||
/// Note that you can only abandon a specific analysis, not a *set* of | ||
/// analyses. | ||
template <typename AnalysisT> void abandon() { abandon(AnalysisT::ID()); } | ||
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/// Mark an analysis as abandoned using its ID. | ||
/// | ||
/// An abandoned analysis is not preserved, even if it is nominally covered | ||
/// by some other set or was previously explicitly marked as preserved. | ||
/// | ||
/// Note that you can only abandon a specific analysis, not a *set* of | ||
/// analyses. | ||
void abandon(AnalysisKey *ID) { | ||
PreservedIDs.erase(ID); | ||
NotPreservedAnalysisIDs.insert(ID); | ||
} | ||
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/// Intersect this set with another in place. | ||
/// | ||
/// This is a mutating operation on this preserved set, removing all | ||
/// preserved passes which are not also preserved in the argument. | ||
void intersect(const PreservedAnalyses &Arg) { | ||
if (Arg.areAllPreserved()) | ||
return; | ||
if (areAllPreserved()) { | ||
*this = Arg; | ||
return; | ||
} | ||
// The intersection requires the *union* of the explicitly not-preserved | ||
// IDs and the *intersection* of the preserved IDs. | ||
for (auto *ID : Arg.NotPreservedAnalysisIDs) { | ||
PreservedIDs.erase(ID); | ||
NotPreservedAnalysisIDs.insert(ID); | ||
} | ||
for (auto *ID : PreservedIDs) | ||
if (!Arg.PreservedIDs.count(ID)) | ||
PreservedIDs.erase(ID); | ||
} | ||
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/// Intersect this set with a temporary other set in place. | ||
/// | ||
/// This is a mutating operation on this preserved set, removing all | ||
/// preserved passes which are not also preserved in the argument. | ||
void intersect(PreservedAnalyses &&Arg) { | ||
if (Arg.areAllPreserved()) | ||
return; | ||
if (areAllPreserved()) { | ||
*this = std::move(Arg); | ||
return; | ||
} | ||
// The intersection requires the *union* of the explicitly not-preserved | ||
// IDs and the *intersection* of the preserved IDs. | ||
for (auto *ID : Arg.NotPreservedAnalysisIDs) { | ||
PreservedIDs.erase(ID); | ||
NotPreservedAnalysisIDs.insert(ID); | ||
} | ||
for (auto *ID : PreservedIDs) | ||
if (!Arg.PreservedIDs.count(ID)) | ||
PreservedIDs.erase(ID); | ||
} | ||
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/// A checker object that makes it easy to query for whether an analysis or | ||
/// some set covering it is preserved. | ||
class PreservedAnalysisChecker { | ||
friend class PreservedAnalyses; | ||
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const PreservedAnalyses &PA; | ||
AnalysisKey *const ID; | ||
const bool IsAbandoned; | ||
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/// A PreservedAnalysisChecker is tied to a particular Analysis because | ||
/// `preserved()` and `preservedSet()` both return false if the Analysis | ||
/// was abandoned. | ||
PreservedAnalysisChecker(const PreservedAnalyses &PA, AnalysisKey *ID) | ||
: PA(PA), ID(ID), IsAbandoned(PA.NotPreservedAnalysisIDs.count(ID)) {} | ||
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public: | ||
/// Returns true if the checker's analysis was not abandoned and either | ||
/// - the analysis is explicitly preserved or | ||
/// - all analyses are preserved. | ||
bool preserved() { | ||
return !IsAbandoned && (PA.PreservedIDs.count(&AllAnalysesKey) || | ||
PA.PreservedIDs.count(ID)); | ||
} | ||
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/// Return true if the checker's analysis was not abandoned, i.e. it was not | ||
/// explicitly invalidated. Even if the analysis is not explicitly | ||
/// preserved, if the analysis is known stateless, then it is preserved. | ||
bool preservedWhenStateless() { return !IsAbandoned; } | ||
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/// Returns true if the checker's analysis was not abandoned and either | ||
/// - \p AnalysisSetT is explicitly preserved or | ||
/// - all analyses are preserved. | ||
template <typename AnalysisSetT> bool preservedSet() { | ||
AnalysisSetKey *SetID = AnalysisSetT::ID(); | ||
return !IsAbandoned && (PA.PreservedIDs.count(&AllAnalysesKey) || | ||
PA.PreservedIDs.count(SetID)); | ||
} | ||
}; | ||
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/// Build a checker for this `PreservedAnalyses` and the specified analysis | ||
/// type. | ||
/// | ||
/// You can use the returned object to query whether an analysis was | ||
/// preserved. See the example in the comment on `PreservedAnalysis`. | ||
template <typename AnalysisT> PreservedAnalysisChecker getChecker() const { | ||
return PreservedAnalysisChecker(*this, AnalysisT::ID()); | ||
} | ||
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/// Build a checker for this `PreservedAnalyses` and the specified analysis | ||
/// ID. | ||
/// | ||
/// You can use the returned object to query whether an analysis was | ||
/// preserved. See the example in the comment on `PreservedAnalysis`. | ||
PreservedAnalysisChecker getChecker(AnalysisKey *ID) const { | ||
return PreservedAnalysisChecker(*this, ID); | ||
} | ||
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/// Test whether all analyses are preserved (and none are abandoned). | ||
/// | ||
/// This is used primarily to optimize for the common case of a transformation | ||
/// which makes no changes to the IR. | ||
bool areAllPreserved() const { | ||
return NotPreservedAnalysisIDs.empty() && | ||
PreservedIDs.count(&AllAnalysesKey); | ||
} | ||
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/// Directly test whether a set of analyses is preserved. | ||
/// | ||
/// This is only true when no analyses have been explicitly abandoned. | ||
template <typename AnalysisSetT> bool allAnalysesInSetPreserved() const { | ||
return allAnalysesInSetPreserved(AnalysisSetT::ID()); | ||
} | ||
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/// Directly test whether a set of analyses is preserved. | ||
/// | ||
/// This is only true when no analyses have been explicitly abandoned. | ||
bool allAnalysesInSetPreserved(AnalysisSetKey *SetID) const { | ||
return NotPreservedAnalysisIDs.empty() && | ||
(PreservedIDs.count(&AllAnalysesKey) || PreservedIDs.count(SetID)); | ||
} | ||
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private: | ||
/// A special key used to indicate all analyses. | ||
static AnalysisSetKey AllAnalysesKey; | ||
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/// The IDs of analyses and analysis sets that are preserved. | ||
SmallPtrSet<void *, 2> PreservedIDs; | ||
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/// The IDs of explicitly not-preserved analyses. | ||
/// | ||
/// If an analysis in this set is covered by a set in `PreservedIDs`, we | ||
/// consider it not-preserved. That is, `NotPreservedAnalysisIDs` always | ||
/// "wins" over analysis sets in `PreservedIDs`. | ||
/// | ||
/// Also, a given ID should never occur both here and in `PreservedIDs`. | ||
SmallPtrSet<AnalysisKey *, 2> NotPreservedAnalysisIDs; | ||
}; | ||
} // namespace llvm | ||
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#endif |
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