Introduces a string attribute, amdgpu-requires-module-lds, to allow eliding the module.lds block from kernels. Will allocate the block as before if the attribute is missing or has its default value of true. Patch uses the new attribute to detect the simplest possible instance of this, where a kernel makes no calls and thus cannot call any functions that use LDS. Tests updated to match, coverage was already good. Interesting cases is in lower-module-lds-offsets where annotating the kernel allows the backend to pick a different (in this case better) variable ordering than previously. A later patch will avoid moving kernel variables into module.lds when the kernel can have this attribute, allowing optimal ordering and locally unused variable elimination. Reviewed By: arsenm Differential Revision: https://reviews.llvm.org/D122091
114 lines
3.2 KiB
C++
114 lines
3.2 KiB
C++
//===-- AMDGPUMachineFunctionInfo.h -------------------------------*- C++ -*-=//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUMACHINEFUNCTION_H
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#define LLVM_LIB_TARGET_AMDGPU_AMDGPUMACHINEFUNCTION_H
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#include "Utils/AMDGPUBaseInfo.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/GlobalValue.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/Module.h"
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namespace llvm {
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class AMDGPUMachineFunction : public MachineFunctionInfo {
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/// A map to keep track of local memory objects and their offsets within the
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/// local memory space.
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SmallDenseMap<const GlobalValue *, unsigned, 4> LocalMemoryObjects;
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protected:
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uint64_t ExplicitKernArgSize = 0; // Cache for this.
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Align MaxKernArgAlign; // Cache for this.
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/// Number of bytes in the LDS that are being used.
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uint32_t LDSSize = 0;
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uint32_t GDSSize = 0;
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/// Number of bytes in the LDS allocated statically. This field is only used
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/// in the instruction selector and not part of the machine function info.
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uint32_t StaticLDSSize = 0;
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uint32_t StaticGDSSize = 0;
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/// Align for dynamic shared memory if any. Dynamic shared memory is
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/// allocated directly after the static one, i.e., LDSSize. Need to pad
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/// LDSSize to ensure that dynamic one is aligned accordingly.
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/// The maximal alignment is updated during IR translation or lowering
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/// stages.
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Align DynLDSAlign;
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// State of MODE register, assumed FP mode.
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AMDGPU::SIModeRegisterDefaults Mode;
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// Kernels + shaders. i.e. functions called by the hardware and not called
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// by other functions.
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bool IsEntryFunction = false;
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// Entry points called by other functions instead of directly by the hardware.
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bool IsModuleEntryFunction = false;
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bool NoSignedZerosFPMath = false;
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// Function may be memory bound.
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bool MemoryBound = false;
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// Kernel may need limited waves per EU for better performance.
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bool WaveLimiter = false;
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public:
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AMDGPUMachineFunction(const MachineFunction &MF);
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uint64_t getExplicitKernArgSize() const {
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return ExplicitKernArgSize;
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}
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unsigned getMaxKernArgAlign() const { return MaxKernArgAlign.value(); }
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uint32_t getLDSSize() const {
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return LDSSize;
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}
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uint32_t getGDSSize() const {
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return GDSSize;
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}
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AMDGPU::SIModeRegisterDefaults getMode() const {
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return Mode;
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}
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bool isEntryFunction() const {
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return IsEntryFunction;
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}
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bool isModuleEntryFunction() const { return IsModuleEntryFunction; }
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bool hasNoSignedZerosFPMath() const {
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return NoSignedZerosFPMath;
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}
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bool isMemoryBound() const {
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return MemoryBound;
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}
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bool needsWaveLimiter() const {
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return WaveLimiter;
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}
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unsigned allocateLDSGlobal(const DataLayout &DL, const GlobalVariable &GV);
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void allocateModuleLDSGlobal(const Function &F);
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Align getDynLDSAlign() const { return DynLDSAlign; }
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void setDynLDSAlign(const DataLayout &DL, const GlobalVariable &GV);
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};
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}
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#endif
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