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/*========================== begin_copyright_notice ============================
Copyright (C) 2017-2021 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#pragma once
#include "common/LLVMWarningsPush.hpp"
#include <llvm/Pass.h>
#include <llvm/ADT/MapVector.h>
#include <llvm/IR/DataLayout.h>
#include <llvm/IR/InstVisitor.h>
#include "common/LLVMWarningsPop.hpp"
#include "llvmWrapper/Support/Alignment.h"
namespace IGC {
/// @brief This pass correctly sets the alignment of all loads
/// and stores according to OpenCL rules.
/// It perform a data-flow analysis to keep track of the highest power
/// of 2 that divides a value.
/// This tracking is performed for integers and for pointers, and is
/// based on the assumption that global variables and kernel arguments
/// are always aligned on their data type.
/// The result is an underapproximation of the actual alignment, so it
/// is always safe.
class AlignmentAnalysis : public llvm::FunctionPass, public llvm::InstVisitor<AlignmentAnalysis, llvm::Align> {
public:
// Pass identification, replacement for typeid
static char ID;
/// @brief Constructor
AlignmentAnalysis();
/// @brief Destructor
~AlignmentAnalysis() {}
/// @brief Provides name of pass
virtual llvm::StringRef getPassName() const override { return "AlignmentAnalysisPass"; }
virtual void getAnalysisUsage(llvm::AnalysisUsage &AU) const override { AU.setPreservesCFG(); }
/// @brief Main entry point.
virtual bool runOnFunction(llvm::Function &F) override;
// @ brief Instruction visitors
llvm::Align visitInstruction(llvm::Instruction &I);
llvm::Align visitAllocaInst(llvm::AllocaInst &I);
llvm::Align visitIntToPtrInst(llvm::IntToPtrInst &I);
llvm::Align visitPtrToIntInst(llvm::PtrToIntInst &I);
llvm::Align visitSelectInst(llvm::SelectInst &I);
llvm::Align visitGetElementPtrInst(llvm::GetElementPtrInst &I);
llvm::Align visitPHINode(llvm::PHINode &I);
llvm::Align visitBitCastInst(llvm::BitCastInst &I);
llvm::Align visitAdd(llvm::BinaryOperator &I);
llvm::Align visitMul(llvm::BinaryOperator &I);
llvm::Align visitShl(llvm::BinaryOperator &I);
llvm::Align visitAnd(llvm::BinaryOperator &I);
llvm::Align visitTruncInst(llvm::TruncInst &I);
llvm::Align visitZExtInst(llvm::ZExtInst &I);
llvm::Align visitSExtInst(llvm::SExtInst &I);
llvm::Align visitCallInst(llvm::CallInst &I);
bool SetInstAlignment(llvm::Instruction &I);
bool SetInstAlignment(llvm::LoadInst &I);
bool SetInstAlignment(llvm::StoreInst &I);
bool SetInstAlignment(llvm::MemSetInst &I);
bool SetInstAlignment(llvm::MemCpyInst &I);
bool SetInstAlignment(llvm::MemMoveInst &I);
protected:
// Check if the function has OpenCL metadata that specifies the alignment of
// its arguments. If it does, set the LLVM alignment attribute of the
// arguments accordingly. This is helpful for passes like InferAlignment.
void setArgumentAlignmentBasedOnOptionalMetadata(llvm::Function &F);
/// @breif Evaluates the alignment of I based on its operands.
/// For Load and Store instructions, also sets the alignment
/// of the operation itself.
/// @param I The instruction to process
bool processInstruction(llvm::Instruction *I);
/// @brief Returns the alignment for V, if it is known.
/// Otherwise, returns the maximum alignment.
/// @param V the value the alignment of which we're interested in
llvm::Align getAlignValue(llvm::Value *V) const;
/// @brief Returns the alignment of a constant integer.
/// This is normally 1 << ctz(C) (the highest power of 2 that divides C),
/// except when C is 0, when it is the max alignment
llvm::Align getConstantAlignment(uint64_t C) const;
/// @brief This map stores the known alignment of every value.
llvm::MapVector<llvm::Value *, llvm::Align> m_alignmentMap;
const llvm::DataLayout *m_DL = nullptr;
};
} // namespace IGC
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