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llvm-mirror/lib/Target/AMDGPU/Utils/AMDGPULDSUtils.h
hsmahesha 37c462f96a [AMDGPU] Replace non-kernel function uses of LDS globals by pointers.
The main motivation behind pointer replacement of LDS use within non-kernel
functions is - to *avoid* subsequent LDS lowering pass from directly packing
LDS (assume large LDS) into a struct type which would otherwise cause allocating
huge memory for struct instance within every kernel.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D103225
2021-06-21 11:51:49 +05:30

71 lines
2.8 KiB
C++

//===- AMDGPULDSUtils.h - LDS related helper functions -*- 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
//
//===----------------------------------------------------------------------===//
//
// AMDGPU LDS related helper utility functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_AMDGPU_UTILS_AMDGPULDSUTILS_H
#define LLVM_LIB_TARGET_AMDGPU_UTILS_AMDGPULDSUTILS_H
#include "AMDGPU.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/IR/Constants.h"
namespace llvm {
class ConstantExpr;
namespace AMDGPU {
/// Collect reachable callees for each kernel defined in the module \p M and
/// return collected callees at \p KernelToCallees.
void collectReachableCallees(
Module &M,
DenseMap<Function *, SmallPtrSet<Function *, 8>> &KernelToCallees);
/// For the given LDS global \p GV, visit all its users and collect all
/// non-kernel functions within which \p GV is used and return collected list of
/// such non-kernel functions.
SmallPtrSet<Function *, 8> collectNonKernelAccessorsOfLDS(GlobalVariable *GV);
/// Collect all the instructions where user \p U belongs to. \p U could be
/// instruction itself or it could be a constant expression which is used within
/// an instruction. If \p CollectKernelInsts is true, collect instructions only
/// from kernels, otherwise collect instructions only from non-kernel functions.
DenseMap<Function *, SmallPtrSet<Instruction *, 8>>
getFunctionToInstsMap(User *U, bool CollectKernelInsts);
bool isKernelCC(const Function *Func);
Align getAlign(DataLayout const &DL, const GlobalVariable *GV);
/// \returns true if a given global variable \p GV (or its global users) appear
/// as an use within some instruction (either from kernel or from non-kernel).
bool hasUserInstruction(const GlobalValue *GV);
/// \returns true if an LDS global requres lowering to a module LDS structure
/// if \p F is not given. If \p F is given it must be a kernel and function
/// \returns true if an LDS global is directly used from that kernel and it
/// is safe to replace its uses with a kernel LDS structure member.
bool shouldLowerLDSToStruct(const GlobalVariable &GV,
const Function *F = nullptr);
std::vector<GlobalVariable *> findVariablesToLower(Module &M,
const Function *F = nullptr);
SmallPtrSet<GlobalValue *, 32> getUsedList(Module &M);
/// Replace all uses of constant \p C with instructions in \p F.
void replaceConstantUsesInFunction(ConstantExpr *C, const Function *F);
} // end namespace AMDGPU
} // end namespace llvm
#endif // LLVM_LIB_TARGET_AMDGPU_UTILS_AMDGPULDSUTILS_H