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//===---- CGLoopInfo.h - LLVM CodeGen for loop 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 is the internal state used for llvm translation for loop statement
// metadata.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
#define LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
class BasicBlock;
class Instruction;
class MDNode;
} // end namespace llvm
namespace clang {
class Attr;
class ASTContext;
class CodeGenOptions;
namespace CodeGen {
/// Attributes that may be specified on loops.
struct LoopAttributes {
explicit LoopAttributes(bool IsParallel = false);
void clear();
/// Generate llvm.loop.parallel metadata for loads and stores.
bool IsParallel;
/// State of loop vectorization or unrolling.
enum LVEnableState { Unspecified, Enable, Disable, Full };
/// Value for llvm.loop.vectorize.enable metadata.
LVEnableState VectorizeEnable;
/// Value for llvm.loop.unroll.* metadata (enable, disable, or full).
LVEnableState UnrollEnable;
/// Value for llvm.loop.unroll_and_jam.* metadata (enable, disable, or full).
LVEnableState UnrollAndJamEnable;
/// Value for llvm.loop.vectorize.predicate metadata
LVEnableState VectorizePredicateEnable;
/// Value for llvm.loop.vectorize.width metadata.
unsigned VectorizeWidth;
/// Value for llvm.loop.interleave.count metadata.
unsigned InterleaveCount;
/// llvm.unroll.
unsigned UnrollCount;
/// llvm.unroll.
unsigned UnrollAndJamCount;
/// Value for llvm.loop.distribute.enable metadata.
LVEnableState DistributeEnable;
/// Value for llvm.loop.pipeline.disable metadata.
bool PipelineDisabled;
/// Value for llvm.loop.pipeline.iicount metadata.
unsigned PipelineInitiationInterval;
/// Value for whether the loop is required to make progress.
bool MustProgress;
};
/// Information used when generating a structured loop.
class LoopInfo {
public:
/// Construct a new LoopInfo for the loop with entry Header.
LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs,
const llvm::DebugLoc &StartLoc, const llvm::DebugLoc &EndLoc,
LoopInfo *Parent);
/// Get the loop id metadata for this loop.
llvm::MDNode *getLoopID() const { return TempLoopID.get(); }
/// Get the header block of this loop.
llvm::BasicBlock *getHeader() const { return Header; }
/// Get the set of attributes active for this loop.
const LoopAttributes &getAttributes() const { return Attrs; }
/// Return this loop's access group or nullptr if it does not have one.
llvm::MDNode *getAccessGroup() const { return AccGroup; }
/// Create the loop's metadata. Must be called after its nested loops have
/// been processed.
void finish();
private:
/// Loop ID metadata.
llvm::TempMDTuple TempLoopID;
/// Header block of this loop.
llvm::BasicBlock *Header;
/// The attributes for this loop.
LoopAttributes Attrs;
/// The access group for memory accesses parallel to this loop.
llvm::MDNode *AccGroup = nullptr;
/// Start location of this loop.
llvm::DebugLoc StartLoc;
/// End location of this loop.
llvm::DebugLoc EndLoc;
/// The next outer loop, or nullptr if this is the outermost loop.
LoopInfo *Parent;
/// If this loop has unroll-and-jam metadata, this can be set by the inner
/// loop's LoopInfo to set the llvm.loop.unroll_and_jam.followup_inner
/// metadata.
llvm::MDNode *UnrollAndJamInnerFollowup = nullptr;
/// Create a LoopID without any transformations.
llvm::MDNode *
createLoopPropertiesMetadata(llvm::ArrayRef<llvm::Metadata *> LoopProperties);
/// Create a LoopID for transformations.
///
/// The methods call each other in case multiple transformations are applied
/// to a loop. The transformation first to be applied will use LoopID of the
/// next transformation in its followup attribute.
///
/// @param Attrs The loop's transformations.
/// @param LoopProperties Non-transformation properties such as debug
/// location, parallel accesses and disabled
/// transformations. These are added to the returned
/// LoopID.
/// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
/// at least one transformation.
///
/// @return A LoopID (metadata node) that can be used for the llvm.loop
/// annotation or followup-attribute.
/// @{
llvm::MDNode *
createPipeliningMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
llvm::MDNode *
createPartialUnrollMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
llvm::MDNode *
createUnrollAndJamMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
llvm::MDNode *
createLoopVectorizeMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
llvm::MDNode *
createLoopDistributeMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
llvm::MDNode *
createFullUnrollMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
/// @}
/// Create a LoopID for this loop, including transformation-unspecific
/// metadata such as debug location.
///
/// @param Attrs This loop's attributes and transformations.
/// @param LoopProperties Additional non-transformation properties to add
/// to the LoopID, such as transformation-specific
/// metadata that are not covered by @p Attrs.
/// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
/// at least one transformation.
///
/// @return A LoopID (metadata node) that can be used for the llvm.loop
/// annotation.
llvm::MDNode *createMetadata(const LoopAttributes &Attrs,
llvm::ArrayRef<llvm::Metadata *> LoopProperties,
bool &HasUserTransforms);
};
/// A stack of loop information corresponding to loop nesting levels.
/// This stack can be used to prepare attributes which are applied when a loop
/// is emitted.
class LoopInfoStack {
LoopInfoStack(const LoopInfoStack &) = delete;
void operator=(const LoopInfoStack &) = delete;
public:
LoopInfoStack() {}
/// Begin a new structured loop. The set of staged attributes will be
/// applied to the loop and then cleared.
void push(llvm::BasicBlock *Header, const llvm::DebugLoc &StartLoc,
const llvm::DebugLoc &EndLoc);
/// Begin a new structured loop. Stage attributes from the Attrs list.
/// The staged attributes are applied to the loop and then cleared.
void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx,
const clang::CodeGenOptions &CGOpts,
llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc,
const llvm::DebugLoc &EndLoc, bool MustProgress = false);
/// End the current loop.
void pop();
/// Return the top loop id metadata.
llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); }
/// Return true if the top loop is parallel.
bool getCurLoopParallel() const {
return hasInfo() ? getInfo().getAttributes().IsParallel : false;
}
/// Function called by the CodeGenFunction when an instruction is
/// created.
void InsertHelper(llvm::Instruction *I) const;
/// Set the next pushed loop as parallel.
void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; }
/// Set the next pushed loop 'vectorize.enable'
void setVectorizeEnable(bool Enable = true) {
StagedAttrs.VectorizeEnable =
Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
}
/// Set the next pushed loop as a distribution candidate.
void setDistributeState(bool Enable = true) {
StagedAttrs.DistributeEnable =
Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
}
/// Set the next pushed loop unroll state.
void setUnrollState(const LoopAttributes::LVEnableState &State) {
StagedAttrs.UnrollEnable = State;
}
/// Set the next pushed vectorize predicate state.
void setVectorizePredicateState(const LoopAttributes::LVEnableState &State) {
StagedAttrs.VectorizePredicateEnable = State;
}
/// Set the next pushed loop unroll_and_jam state.
void setUnrollAndJamState(const LoopAttributes::LVEnableState &State) {
StagedAttrs.UnrollAndJamEnable = State;
}
/// Set the vectorize width for the next loop pushed.
void setVectorizeWidth(unsigned W) { StagedAttrs.VectorizeWidth = W; }
/// Set the interleave count for the next loop pushed.
void setInterleaveCount(unsigned C) { StagedAttrs.InterleaveCount = C; }
/// Set the unroll count for the next loop pushed.
void setUnrollCount(unsigned C) { StagedAttrs.UnrollCount = C; }
/// \brief Set the unroll count for the next loop pushed.
void setUnrollAndJamCount(unsigned C) { StagedAttrs.UnrollAndJamCount = C; }
/// Set the pipeline disabled state.
void setPipelineDisabled(bool S) { StagedAttrs.PipelineDisabled = S; }
/// Set the pipeline initiation interval.
void setPipelineInitiationInterval(unsigned C) {
StagedAttrs.PipelineInitiationInterval = C;
}
/// Set no progress for the next loop pushed.
void setMustProgress(bool P) { StagedAttrs.MustProgress = P; }
private:
/// Returns true if there is LoopInfo on the stack.
bool hasInfo() const { return !Active.empty(); }
/// Return the LoopInfo for the current loop. HasInfo should be called
/// first to ensure LoopInfo is present.
const LoopInfo &getInfo() const { return *Active.back(); }
/// The set of attributes that will be applied to the next pushed loop.
LoopAttributes StagedAttrs;
/// Stack of active loops.
llvm::SmallVector<std::unique_ptr<LoopInfo>, 4> Active;
};
} // end namespace CodeGen
} // end namespace clang
#endif