llvm-project/llvm/lib/TargetParser/ARMTargetParserCommon.cpp

//===---------------- ARMTargetParserCommon ---------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Code that is common to ARMTargetParser and AArch64TargetParser.
//
//===----------------------------------------------------------------------===//

#include "llvm/TargetParser/ARMTargetParserCommon.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringSwitch.h"

using namespace llvm;

StringRef ARM::getArchSynonym(StringRef Arch) {
  return StringSwitch<StringRef>(Arch)
      .Case("v5", "v5t")
      .Case("v5e", "v5te")
      .Case("v6j", "v6")
      .Case("v6hl", "v6k")
      .Cases("v6m", "v6sm", "v6s-m", "v6-m")
      .Cases("v6z", "v6zk", "v6kz")
      .Cases("v7", "v7a", "v7hl", "v7l", "v7-a")
      .Case("v7r", "v7-r")
      .Case("v7m", "v7-m")
      .Case("v7em", "v7e-m")
      .Cases("v8", "v8a", "v8l", "aarch64", "arm64", "v8-a")
      .Case("v8.1a", "v8.1-a")
      .Case("v8.2a", "v8.2-a")
      .Case("v8.3a", "v8.3-a")
      .Case("v8.4a", "v8.4-a")
      .Case("v8.5a", "v8.5-a")
      .Case("v8.6a", "v8.6-a")
      .Case("v8.7a", "v8.7-a")
      .Case("v8.8a", "v8.8-a")
      .Case("v8.9a", "v8.9-a")
      .Case("v8r", "v8-r")
      .Cases("v9", "v9a", "v9-a")
      .Case("v9.1a", "v9.1-a")
      .Case("v9.2a", "v9.2-a")
      .Case("v9.3a", "v9.3-a")
      .Case("v9.4a", "v9.4-a")
      .Case("v9.5a", "v9.5-a")
      .Case("v8m.base", "v8-m.base")
      .Case("v8m.main", "v8-m.main")
      .Case("v8.1m.main", "v8.1-m.main")
      .Default(Arch);
}

StringRef ARM::getCanonicalArchName(StringRef Arch) {
  size_t offset = StringRef::npos;
  StringRef A = Arch;
  StringRef Error = "";

  // Begins with "arm" / "thumb", move past it.
  if (A.starts_with("arm64_32"))
    offset = 8;
  else if (A.starts_with("arm64e"))
    offset = 6;
  else if (A.starts_with("arm64"))
    offset = 5;
  else if (A.starts_with("aarch64_32"))
    offset = 10;
  else if (A.starts_with("arm"))
    offset = 3;
  else if (A.starts_with("thumb"))
    offset = 5;
  else if (A.starts_with("aarch64")) {
    offset = 7;
    // AArch64 uses "_be", not "eb" suffix.
    if (A.contains("eb"))
      return Error;
    if (A.substr(offset, 3) == "_be")
      offset += 3;
  }

  // Ex. "armebv7", move past the "eb".
  if (offset != StringRef::npos && A.substr(offset, 2) == "eb")
    offset += 2;
  // Or, if it ends with eb ("armv7eb"), chop it off.
  else if (A.ends_with("eb"))
    A = A.substr(0, A.size() - 2);
  // Trim the head
  if (offset != StringRef::npos)
    A = A.substr(offset);

  // Empty string means offset reached the end, which means it's valid.
  if (A.empty())
    return Arch;

  // Only match non-marketing names
  if (offset != StringRef::npos) {
    // Must start with 'vN'.
    if (A.size() >= 2 && (A[0] != 'v' || !std::isdigit(A[1])))
      return Error;
    // Can't have an extra 'eb'.
    if (A.contains("eb"))
      return Error;
  }

  // Arch will either be a 'v' name (v7a) or a marketing name (xscale).
  return A;
}

ARM::ISAKind ARM::parseArchISA(StringRef Arch) {
  return StringSwitch<ISAKind>(Arch)
      .StartsWith("aarch64", ISAKind::AARCH64)
      .StartsWith("arm64", ISAKind::AARCH64)
      .StartsWith("thumb", ISAKind::THUMB)
      .StartsWith("arm", ISAKind::ARM)
      .Default(ISAKind::INVALID);
}

ARM::EndianKind ARM::parseArchEndian(StringRef Arch) {
  if (Arch.starts_with("armeb") || Arch.starts_with("thumbeb") ||
      Arch.starts_with("aarch64_be"))
    return EndianKind::BIG;

  if (Arch.starts_with("arm") || Arch.starts_with("thumb")) {
    if (Arch.ends_with("eb"))
      return EndianKind::BIG;
    else
      return EndianKind::LITTLE;
  }

  if (Arch.starts_with("aarch64") || Arch.starts_with("aarch64_32"))
    return EndianKind::LITTLE;

  return EndianKind::INVALID;
}

// Parse a branch protection specification, which has the form
//   standard | none | [bti,pac-ret[+b-key,+leaf,+pc]*]
// Returns true on success, with individual elements of the specification
// returned in `PBP`. Returns false in error, with `Err` containing
// an erroneous part of the spec.
bool ARM::parseBranchProtection(StringRef Spec, ParsedBranchProtection &PBP,
                                StringRef &Err, bool EnablePAuthLR) {
  PBP = {"none", "a_key", false, false, false};
  if (Spec == "none")
    return true; // defaults are ok

  if (Spec == "standard") {
    PBP.Scope = "non-leaf";
    PBP.BranchTargetEnforcement = true;
    PBP.GuardedControlStack = true;
    PBP.BranchProtectionPAuthLR = EnablePAuthLR;
    return true;
  }

  SmallVector<StringRef, 4> Opts;
  Spec.split(Opts, "+");
  for (int I = 0, E = Opts.size(); I != E; ++I) {
    StringRef Opt = Opts[I].trim();
    if (Opt == "bti") {
      PBP.BranchTargetEnforcement = true;
      continue;
    }
    if (Opt == "pac-ret") {
      PBP.Scope = "non-leaf";
      for (; I + 1 != E; ++I) {
        StringRef PACOpt = Opts[I + 1].trim();
        if (PACOpt == "leaf")
          PBP.Scope = "all";
        else if (PACOpt == "b-key")
          PBP.Key = "b_key";
        else if (PACOpt == "pc")
          PBP.BranchProtectionPAuthLR = true;
        else
          break;
      }
      continue;
    }
    if (Opt == "gcs") {
      PBP.GuardedControlStack = true;
      continue;
    }
    if (Opt == "")
      Err = "<empty>";
    else
      Err = Opt;
    return false;
  }

  return true;
}