SubtargetFeature.cpp

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//===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
/// \file Implements the SubtargetFeature interface.
//
//===----------------------------------------------------------------------===//
 
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstring>
#include <iterator>
#include <string>
#include <vector>
 
using namespace llvm;
 
/// Splits a string of comma separated items in to a vector of strings.
void SubtargetFeatures::Split(std::vector<std::string> &V, StringRef S) {
  SmallVector<StringRef, 3> Tmp;
  S.split(Tmp, ',', -1, false /* KeepEmpty */);
  V.reserve(Tmp.size());
  for (StringRef T : Tmp)
    V.push_back(std::string(T));
}
 
void SubtargetFeatures::AddFeature(StringRef String, bool Enable) {
  // Don't add empty features.
  if (!String.empty())
    // Convert to lowercase, prepend flag if we don't already have a flag.
    Features.push_back(hasFlag(String) ? String.lower()
                                       : (Enable ? "+" : "-") + String.lower());
}
 
SubtargetFeatures::SubtargetFeatures(StringRef Initial) {
  // Break up string into separate features
  Split(Features, Initial);
}
 
std::string SubtargetFeatures::getString() const {
  return join(Features.begin(), Features.end(), ",");
}
 
void SubtargetFeatures::print(raw_ostream &OS) const {
  for (auto &F : Features)
    OS << F << " ";
  OS << "\n";
}
 
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void SubtargetFeatures::dump() const {
  print(dbgs());
}
#endif
 
void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
  // FIXME: This is an inelegant way of specifying the features of a
  // subtarget. It would be better if we could encode this information
  // into the IR. See <rdar://5972456>.
  if (Triple.getVendor() == Triple::Apple) {
    if (Triple.getArch() == Triple::ppc) {
      // powerpc-apple-*
      AddFeature("altivec");
    } else if (Triple.getArch() == Triple::ppc64) {
      // powerpc64-apple-*
      AddFeature("64bit");
      AddFeature("altivec");
    }
  }
}