lib/CodeGen/TargetOptionsImpl.cpp

//===-- TargetOptionsImpl.cpp - Options that apply to all targets ----------==//
//
// 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 file implements the methods in the TargetOptions.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/StringSwitch.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;

/// DisableFramePointerElim - This returns true if frame pointer elimination
/// optimization should be disabled for the given machine function.
bool TargetOptions::DisableFramePointerElim(const MachineFunction &MF) const {
  const Function &F = MF.getFunction();

  Attribute FPAttr = F.getFnAttribute("frame-pointer");
  if (!FPAttr.isValid())
    return false;
  StringRef FP = FPAttr.getValueAsString();
  if (FP == "all")
    return true;
  if (FP == "non-leaf")
    return MF.getFrameInfo().hasCalls();
  if (FP == "none" || FP == "reserved")
    return false;
  llvm_unreachable("unknown frame pointer flag");
}

bool TargetOptions::FramePointerIsReserved(const MachineFunction &MF) const {
  const Function &F = MF.getFunction();
  Attribute FPAttr = F.getFnAttribute("frame-pointer");
  if (!FPAttr.isValid())
    return false;

  return StringSwitch<bool>(FPAttr.getValueAsString())
      .Cases("all", "non-leaf", "reserved", true)
      .Case("none", false);
}

/// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
/// that the rounding mode of the FPU can change from its default.
bool TargetOptions::HonorSignDependentRoundingFPMath() const {
  return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
}

/// NOTE: There are targets that still do not support the debug entry values
/// production and that is being controlled with the SupportsDebugEntryValues.
/// In addition, SCE debugger does not have the feature implemented, so prefer
/// not to emit the debug entry values in that case.
/// The EnableDebugEntryValues can be used for the testing purposes.
bool TargetOptions::ShouldEmitDebugEntryValues() const {
  return (SupportsDebugEntryValues && DebuggerTuning != DebuggerKind::SCE) ||
         EnableDebugEntryValues;
}