//===--- XRayArgs.cpp - Arguments for XRay --------------------------------===//
//
// 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 "clang/Driver/XRayArgs.h"
#include "ToolChains/CommonArgs.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Options.h"
#include "clang/Driver/ToolChain.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Support/SpecialCaseList.h"

using namespace clang;
using namespace clang::driver;
using namespace llvm::opt;

namespace {
constexpr char XRayInstrumentOption[] = "-fxray-instrument";
constexpr char XRayInstructionThresholdOption[] =
    "-fxray-instruction-threshold=";
constexpr const char *const XRaySupportedModes[] = {"xray-fdr", "xray-basic"};
} // namespace

XRayArgs::XRayArgs(const ToolChain &TC, const ArgList &Args) {
  const Driver &D = TC.getDriver();
  const llvm::Triple &Triple = TC.getTriple();
  if (Args.hasFlag(options::OPT_fxray_instrument,
                   options::OPT_fnoxray_instrument, false)) {
    if (Triple.getOS() == llvm::Triple::Linux) {
      switch (Triple.getArch()) {
      case llvm::Triple::x86_64:
      case llvm::Triple::arm:
      case llvm::Triple::aarch64:
      case llvm::Triple::ppc64le:
      case llvm::Triple::mips:
      case llvm::Triple::mipsel:
      case llvm::Triple::mips64:
      case llvm::Triple::mips64el:
        break;
      default:
        D.Diag(diag::err_drv_clang_unsupported)
            << (std::string(XRayInstrumentOption) + " on " + Triple.str());
      }
    } else if (Triple.isOSFreeBSD() ||
               Triple.isOSOpenBSD() ||
               Triple.isOSNetBSD() ||
               Triple.getOS() == llvm::Triple::Darwin) {
      if (Triple.getArch() != llvm::Triple::x86_64) {
        D.Diag(diag::err_drv_clang_unsupported)
            << (std::string(XRayInstrumentOption) + " on " + Triple.str());
      }
    } else if (Triple.getOS() == llvm::Triple::Fuchsia) {
      switch (Triple.getArch()) {
      case llvm::Triple::x86_64:
      case llvm::Triple::aarch64:
        break;
      default:
        D.Diag(diag::err_drv_clang_unsupported)
            << (std::string(XRayInstrumentOption) + " on " + Triple.str());
      }
    } else {
      D.Diag(diag::err_drv_clang_unsupported)
          << (std::string(XRayInstrumentOption) + " on " + Triple.str());
    }
    XRayInstrument = true;
    if (const Arg *A =
            Args.getLastArg(options::OPT_fxray_instruction_threshold_,
                            options::OPT_fxray_instruction_threshold_EQ)) {
      StringRef S = A->getValue();
      if (S.getAsInteger(0, InstructionThreshold) || InstructionThreshold < 0)
        D.Diag(clang::diag::err_drv_invalid_value) << A->getAsString(Args) << S;
    }

    // By default, the back-end will not emit the lowering for XRay customevent
    // calls if the function is not instrumented. In the future we will change
    // this default to be the reverse, but in the meantime we're going to
    // introduce the new functionality behind a flag.
    if (Args.hasFlag(options::OPT_fxray_always_emit_customevents,
                     options::OPT_fnoxray_always_emit_customevents, false))
      XRayAlwaysEmitCustomEvents = true;

    if (Args.hasFlag(options::OPT_fxray_always_emit_typedevents,
                     options::OPT_fnoxray_always_emit_typedevents, false))
      XRayAlwaysEmitTypedEvents = true;

    if (!Args.hasFlag(options::OPT_fxray_link_deps,
                      options::OPT_fnoxray_link_deps, true))
      XRayRT = false;

    auto Bundles =
        Args.getAllArgValues(options::OPT_fxray_instrumentation_bundle);
    if (Bundles.empty())
      InstrumentationBundle.Mask = XRayInstrKind::All;
    else
      for (const auto &B : Bundles) {
        llvm::SmallVector<StringRef, 2> BundleParts;
        llvm::SplitString(B, BundleParts, ",");
        for (const auto &P : BundleParts) {
          // TODO: Automate the generation of the string case table.
          auto Valid = llvm::StringSwitch<bool>(P)
                           .Cases("none", "all", "function", "custom", true)
                           .Default(false);

          if (!Valid) {
            D.Diag(clang::diag::err_drv_invalid_value)
                << "-fxray-instrumentation-bundle=" << P;
            continue;
          }

          auto Mask = parseXRayInstrValue(P);
          if (Mask == XRayInstrKind::None) {
            InstrumentationBundle.clear();
            break;
          }

          InstrumentationBundle.Mask |= Mask;
        }
      }

    // Validate the always/never attribute files. We also make sure that they
    // are treated as actual dependencies.
    for (const auto &Filename :
         Args.getAllArgValues(options::OPT_fxray_always_instrument)) {
      if (llvm::sys::fs::exists(Filename)) {
        AlwaysInstrumentFiles.push_back(Filename);
        ExtraDeps.push_back(Filename);
      } else
        D.Diag(clang::diag::err_drv_no_such_file) << Filename;
    }

    for (const auto &Filename :
         Args.getAllArgValues(options::OPT_fxray_never_instrument)) {
      if (llvm::sys::fs::exists(Filename)) {
        NeverInstrumentFiles.push_back(Filename);
        ExtraDeps.push_back(Filename);
      } else
        D.Diag(clang::diag::err_drv_no_such_file) << Filename;
    }

    for (const auto &Filename :
         Args.getAllArgValues(options::OPT_fxray_attr_list)) {
      if (llvm::sys::fs::exists(Filename)) {
        AttrListFiles.push_back(Filename);
        ExtraDeps.push_back(Filename);
      } else
        D.Diag(clang::diag::err_drv_no_such_file) << Filename;
    }

    // Get the list of modes we want to support.
    auto SpecifiedModes = Args.getAllArgValues(options::OPT_fxray_modes);
    if (SpecifiedModes.empty())
      llvm::copy(XRaySupportedModes, std::back_inserter(Modes));
    else
      for (const auto &Arg : SpecifiedModes) {
        // Parse CSV values for -fxray-modes=...
        llvm::SmallVector<StringRef, 2> ModeParts;
        llvm::SplitString(Arg, ModeParts, ",");
        for (const auto &M : ModeParts)
          if (M == "none")
            Modes.clear();
          else if (M == "all")
            llvm::copy(XRaySupportedModes, std::back_inserter(Modes));
          else
            Modes.push_back(M);
      }

    // Then we want to sort and unique the modes we've collected.
    llvm::sort(Modes);
    Modes.erase(std::unique(Modes.begin(), Modes.end()), Modes.end());
  }
}

void XRayArgs::addArgs(const ToolChain &TC, const ArgList &Args,
                       ArgStringList &CmdArgs, types::ID InputType) const {
  if (!XRayInstrument)
    return;

  CmdArgs.push_back(XRayInstrumentOption);

  if (XRayAlwaysEmitCustomEvents)
    CmdArgs.push_back("-fxray-always-emit-customevents");

  if (XRayAlwaysEmitTypedEvents)
    CmdArgs.push_back("-fxray-always-emit-typedevents");

  CmdArgs.push_back(Args.MakeArgString(Twine(XRayInstructionThresholdOption) +
                                       Twine(InstructionThreshold)));

  for (const auto &Always : AlwaysInstrumentFiles) {
    SmallString<64> AlwaysInstrumentOpt("-fxray-always-instrument=");
    AlwaysInstrumentOpt += Always;
    CmdArgs.push_back(Args.MakeArgString(AlwaysInstrumentOpt));
  }

  for (const auto &Never : NeverInstrumentFiles) {
    SmallString<64> NeverInstrumentOpt("-fxray-never-instrument=");
    NeverInstrumentOpt += Never;
    CmdArgs.push_back(Args.MakeArgString(NeverInstrumentOpt));
  }

  for (const auto &AttrFile : AttrListFiles) {
    SmallString<64> AttrListFileOpt("-fxray-attr-list=");
    AttrListFileOpt += AttrFile;
    CmdArgs.push_back(Args.MakeArgString(AttrListFileOpt));
  }

  for (const auto &Dep : ExtraDeps) {
    SmallString<64> ExtraDepOpt("-fdepfile-entry=");
    ExtraDepOpt += Dep;
    CmdArgs.push_back(Args.MakeArgString(ExtraDepOpt));
  }

  for (const auto &Mode : Modes) {
    SmallString<64> ModeOpt("-fxray-modes=");
    ModeOpt += Mode;
    CmdArgs.push_back(Args.MakeArgString(ModeOpt));
  }

  SmallString<64> Bundle("-fxray-instrumentation-bundle=");
  if (InstrumentationBundle.full()) {
    Bundle += "all";
  } else if (InstrumentationBundle.empty()) {
    Bundle += "none";
  } else {
    if (InstrumentationBundle.has(XRayInstrKind::Function))
      Bundle += "function";
    if (InstrumentationBundle.has(XRayInstrKind::Custom))
      Bundle += "custom";
    if (InstrumentationBundle.has(XRayInstrKind::Typed))
      Bundle += "typed";
  }
  CmdArgs.push_back(Args.MakeArgString(Bundle));
}