llvm/lib/MC/SubtargetFeature.cpp

   1 //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 /// \file Implements the SubtargetFeature interface.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/MC/SubtargetFeature.h"
  14 #include "llvm/ADT/SmallVector.h"
  15 #include "llvm/ADT/StringExtras.h"
  16 #include "llvm/ADT/StringRef.h"
  17 #include "llvm/ADT/Triple.h"
  18 #include "llvm/Config/llvm-config.h"
  19 #include "llvm/Support/Compiler.h"
  20 #include "llvm/Support/Debug.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include <algorithm>
  23 #include <cassert>
  24 #include <cstddef>
  25 #include <cstring>
  26 #include <iterator>
  27 #include <string>
  28 #include <vector>
  29
  30 using namespace llvm;
  31
  32 /// Splits a string of comma separated items in to a vector of strings.
  33 void SubtargetFeatures::Split(std::vector<std::string> &V, StringRef S) {
  34   SmallVector<StringRef, 3> Tmp;
  35   S.split(Tmp, ',', -1, false /* KeepEmpty */);
  36   V.reserve(Tmp.size());
  37   for (StringRef T : Tmp)
  38     V.push_back(std::string(T));
  39 }
  40
  41 void SubtargetFeatures::AddFeature(StringRef String, bool Enable) {
  42   // Don't add empty features.
  43   if (!String.empty())
  44     // Convert to lowercase, prepend flag if we don't already have a flag.
  45     Features.push_back(hasFlag(String) ? String.lower()
  46                                        : (Enable ? "+" : "-") + String.lower());
  47 }
  48
  49 SubtargetFeatures::SubtargetFeatures(StringRef Initial) {
  50   // Break up string into separate features
  51   Split(Features, Initial);
  52 }
  53
  54 std::string SubtargetFeatures::getString() const {
  55   return join(Features.begin(), Features.end(), ",");
  56 }
  57
  58 void SubtargetFeatures::print(raw_ostream &OS) const {
  59   for (auto &F : Features)
  60     OS << F << " ";
  61   OS << "\n";
  62 }
  63
  64 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  65 LLVM_DUMP_METHOD void SubtargetFeatures::dump() const {
  66   print(dbgs());
  67 }
  68 #endif
  69
  70 void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
  71   // FIXME: This is an inelegant way of specifying the features of a
  72   // subtarget. It would be better if we could encode this information
  73   // into the IR. See <rdar://5972456>.
  74   if (Triple.getVendor() == Triple::Apple) {
  75     if (Triple.getArch() == Triple::ppc) {
  76       // powerpc-apple-*
  77       AddFeature("altivec");
  78     } else if (Triple.getArch() == Triple::ppc64) {
  79       // powerpc64-apple-*
  80       AddFeature("64bit");
  81       AddFeature("altivec");
  82     }
  83   }
  84 }