xref: /llvm-project-15.0.7/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp (revision 13e49dce)

//===-- AMDGPUMachineFunctionInfo.cpp ---------------------------------------=//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "AMDGPUMachineFunction.h"
#include "AMDGPUPerfHintAnalysis.h"
#include "AMDGPUSubtarget.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/Target/TargetMachine.h"

using namespace llvm;

AMDGPUMachineFunction::AMDGPUMachineFunction(const MachineFunction &MF)
    : MachineFunctionInfo(), Mode(MF.getFunction()),
      IsEntryFunction(
          AMDGPU::isEntryFunctionCC(MF.getFunction().getCallingConv())),
      IsModuleEntryFunction(
          AMDGPU::isModuleEntryFunctionCC(MF.getFunction().getCallingConv())),
      NoSignedZerosFPMath(MF.getTarget().Options.NoSignedZerosFPMath) {
  const AMDGPUSubtarget &ST = AMDGPUSubtarget::get(MF);

  // FIXME: Should initialize KernArgSize based on ExplicitKernelArgOffset,
  // except reserved size is not correctly aligned.
  const Function &F = MF.getFunction();

  Attribute MemBoundAttr = F.getFnAttribute("amdgpu-memory-bound");
  MemoryBound = MemBoundAttr.isStringAttribute() &&
                MemBoundAttr.getValueAsString() == "true";

  Attribute WaveLimitAttr = F.getFnAttribute("amdgpu-wave-limiter");
  WaveLimiter = WaveLimitAttr.isStringAttribute() &&
                WaveLimitAttr.getValueAsString() == "true";

  CallingConv::ID CC = F.getCallingConv();
  if (CC == CallingConv::AMDGPU_KERNEL || CC == CallingConv::SPIR_KERNEL)
    ExplicitKernArgSize = ST.getExplicitKernArgSize(F, MaxKernArgAlign);
}

unsigned AMDGPUMachineFunction::allocateLDSGlobal(const DataLayout &DL,
                                                  const GlobalVariable &GV) {
  auto Entry = LocalMemoryObjects.insert(std::make_pair(&GV, 0));
  if (!Entry.second)
    return Entry.first->second;

  Align Alignment =
      DL.getValueOrABITypeAlignment(GV.getAlign(), GV.getValueType());

  /// TODO: We should sort these to minimize wasted space due to alignment
  /// padding. Currently the padding is decided by the first encountered use
  /// during lowering.
  unsigned Offset = StaticLDSSize = alignTo(StaticLDSSize, Alignment);

  Entry.first->second = Offset;
  StaticLDSSize += DL.getTypeAllocSize(GV.getValueType());

  // Update the LDS size considering the padding to align the dynamic shared
  // memory.
  LDSSize = alignTo(StaticLDSSize, DynLDSAlign);

  return Offset;
}

void AMDGPUMachineFunction::allocateModuleLDSGlobal(const Module *M) {
  if (isModuleEntryFunction()) {
    GlobalVariable *GV = M->getGlobalVariable("llvm.amdgcn.module.lds");
    if (GV) {
      unsigned Offset = allocateLDSGlobal(M->getDataLayout(), *GV);
      (void)Offset;
      assert(Offset == 0 &&
             "Module LDS expected to be allocated before other LDS");
    }
  }
}

void AMDGPUMachineFunction::setDynLDSAlign(const DataLayout &DL,
                                           const GlobalVariable &GV) {
  assert(DL.getTypeAllocSize(GV.getValueType()).isZero());

  Align Alignment =
      DL.getValueOrABITypeAlignment(GV.getAlign(), GV.getValueType());
  if (Alignment <= DynLDSAlign)
    return;

  LDSSize = alignTo(StaticLDSSize, Alignment);
  DynLDSAlign = Alignment;
}