// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.rules.cpp;

import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Multimap;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration.LabelConverter;
import com.google.devtools.build.lib.analysis.config.CompilationMode;
import com.google.devtools.build.lib.analysis.config.FragmentOptions;
import com.google.devtools.build.lib.analysis.config.PerLabelOptions;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
import com.google.devtools.build.lib.rules.cpp.CppConfiguration.LibcTop;
import com.google.devtools.build.lib.rules.cpp.CppConfiguration.StripMode;
import com.google.devtools.build.lib.util.OptionsUtils;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LipoMode;
import com.google.devtools.common.options.Converter;
import com.google.devtools.common.options.EnumConverter;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionsParsingException;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Command-line options for C++.
 */
public class CppOptions extends FragmentOptions {

  /**
   * Converts a comma-separated list of compilation mode settings to a properly typed List.
   */
  public static class FissionOptionConverter implements Converter<List<CompilationMode>> {
    @Override
    public List<CompilationMode> convert(String input) throws OptionsParsingException {
      ImmutableSet.Builder<CompilationMode> modes = ImmutableSet.builder();
      if (input.equals("yes")) { // Special case: enable all modes.
        modes.add(CompilationMode.values());
      } else if (!input.equals("no")) { // "no" is another special case that disables all modes.
        CompilationMode.Converter modeConverter = new CompilationMode.Converter();
        for (String mode : Splitter.on(',').split(input)) {
          modes.add(modeConverter.convert(mode));
        }
      }
      return modes.build().asList();
    }

    @Override
    public String getTypeDescription() {
      return "a set of compilation modes";
    }
  }

  /**
   * The same as DynamicMode, but on command-line we also allow AUTO.
   */
  public enum DynamicModeFlag {
    OFF,
    DEFAULT,
    FULLY,
    AUTO
  }

  /**
   * Converter for DynamicModeFlag
   */
  public static class DynamicModeConverter extends EnumConverter<DynamicModeFlag> {
    public DynamicModeConverter() {
      super(DynamicModeFlag.class, "dynamic mode");
    }
  }

  /**
   * Converter for the --strip option.
   */
  public static class StripModeConverter extends EnumConverter<StripMode> {
    public StripModeConverter() {
      super(StripMode.class, "strip mode");
    }
  }

  private static final String LIBC_RELATIVE_LABEL = ":everything";

  /**
   * Converts a String, which is an absolute path or label into a LibcTop
   * object.
   */
  public static class LibcTopConverter implements Converter<LibcTop> {
    @Override
    public LibcTop convert(String input) throws OptionsParsingException {
      if (input.equals("default")) {
        // This is needed for defining config_setting() values, the syntactic form
        // of which must be a String, to match absence of a --grte_top option.
        // "--grte_top=default" works on the command-line too,
        // but that's an inconsequential side-effect, not the intended purpose.
        return null;
      }
      if (!input.startsWith("//")) {
        throw new OptionsParsingException("Not a label");
      }
      try {
        Label label = Label.parseAbsolute(input).getRelative(LIBC_RELATIVE_LABEL);
        return new LibcTop(label);
      } catch (LabelSyntaxException e) {
        throw new OptionsParsingException(e.getMessage());
      }
    }

    @Override
    public String getTypeDescription() {
      return "a label";
    }
  }

  /**
   * Converter for the --lipo option.
   */
  public static class LipoModeConverter extends EnumConverter<LipoMode> {
    public LipoModeConverter() {
      super(LipoMode.class, "LIPO mode");
    }
  }

  @Option(
    name = "lipo input collector",
    defaultValue = "false",
    category = "undocumented",
    help = "Internal flag, only used to create configurations with the LIPO-collector flag set."
  )
  public boolean lipoCollector;

  @Option(
    name = "crosstool_top",
    defaultValue = "@bazel_tools//tools/cpp:toolchain",
    category = "version",
    converter = LabelConverter.class,
    help = "The label of the crosstool package to be used for compiling C++ code."
  )
  public Label crosstoolTop;

  @Option(
    name = "compiler",
    defaultValue = "null",
    category = "version",
    help = "The C++ compiler to use for compiling the target."
  )
  public String cppCompiler;

  @Option(
    name = "glibc",
    defaultValue = "null",
    category = "version",
    help =
        "The version of glibc the target should be linked against. "
            + "By default, a suitable version is chosen based on --cpu."
  )
  public String glibc;

  // O intrepid reaper of unused options: Be warned that the [no]start_end_lib
  // option, however tempting to remove, has a use case. Look in our telemetry data.
  @Option(
    name = "start_end_lib",
    defaultValue = "true",
    category = "strategy", // but also adds edges to the action graph
    help = "Use the --start-lib/--end-lib ld options if supported by the toolchain."
  )
  public boolean useStartEndLib;

  @Option(
    name = "interface_shared_objects",
    defaultValue = "true",
    category = "strategy", // but also adds edges to the action graph
    help =
        "Use interface shared objects if supported by the toolchain. "
            + "All ELF toolchains currently support this setting."
  )
  public boolean useInterfaceSharedObjects;

  @Option(
    name = "fission",
    defaultValue = "no",
    converter = FissionOptionConverter.class,
    category = "semantics",
    help =
        "Specifies which compilation modes use fission for C++ compilations and links. "
            + " May be any combination of {'fastbuild', 'dbg', 'opt'} or the special values 'yes' "
            + " to enable all modes and 'no' to disable all modes."
  )
  public List<CompilationMode> fissionModes;

  @Option(
    name = "build_test_dwp",
    defaultValue = "false",
    category = "semantics",
    help =
        "If enabled, when building C++ tests statically and with fission the .dwp file "
            + " for the test binary will be automatically built as well."
  )
  public boolean buildTestDwp;

  @Option(
    name = "dynamic_mode",
    defaultValue = "default",
    converter = DynamicModeConverter.class,
    category = "semantics",
    help =
        "Determines whether C++ binaries will be linked dynamically.  'default' means "
            + "blaze will choose whether to link dynamically.  'fully' means all libraries "
            + "will be linked dynamically. 'off' means that all libraries will be linked "
            + "in mostly static mode."
  )
  public DynamicModeFlag dynamicMode;

  @Option(
    name = "experimental_link_compile_output_separately",
    defaultValue = "false",
    category = "semantics",
    help =
        "This flag is experimental and may go away at any time.  "
            + "If true, dynamically linked binary targets will build and link their own srcs as "
            + "a dynamic library instead of directly linking it in."
  )
  public boolean linkCompileOutputSeparately;

  @Option(
    name = "force_pic",
    defaultValue = "false",
    category = "semantics",
    help =
        "If enabled, all C++ compilations produce position-independent code (\"-fPIC\"),"
            + " links prefer PIC pre-built libraries over non-PIC libraries, and links produce"
            + " position-independent executables (\"-pie\")."
  )
  public boolean forcePic;

  @Option(
    name = "force_ignore_dash_static",
    defaultValue = "false",
    category = "semantics",
    help = "If set, '-static' options in the linkopts of cc_* rules will be ignored."
  )
  public boolean forceIgnoreDashStatic;

  @Option(
    name = "experimental_skip_static_outputs",
    defaultValue = "false",
    category = "semantics",
    help =
        "This flag is experimental and may go away at any time.  "
            + "If true, linker output for mostly-static C++ executables is a tiny amount of "
            + "dummy dependency information, and NOT a usable binary.  Kludge, but can reduce "
            + "network and disk I/O load (and thus, continuous build cycle times) by a lot.  "
            + "NOTE: use of this flag REQUIRES --distinct_host_configuration."
  )
  public boolean skipStaticOutputs;

  // TODO(djasper): Remove once it has been removed from the global blazerc.
  @Option(
    name = "send_transitive_header_module_srcs",
    defaultValue = "true",
    category = "semantics",
    help = "Obsolete. Don't use."
  )
  public boolean sendTransitiveHeaderModuleSrcs;

  @Option(
    name = "process_headers_in_dependencies",
    defaultValue = "false",
    category = "semantics",
    help =
        "When building a target //a:a, process headers in all targets that //a:a depends "
            + "on (if header processing is enabled for the toolchain)."
  )
  public boolean processHeadersInDependencies;

  @Option(
    name = "copt",
    allowMultiple = true,
    defaultValue = "",
    category = "flags",
    help = "Additional options to pass to gcc."
  )
  public List<String> coptList;

  @Option(
    name = "cxxopt",
    defaultValue = "",
    category = "flags",
    allowMultiple = true,
    help = "Additional option to pass to gcc when compiling C++ source files."
  )
  public List<String> cxxoptList;

  @Option(
    name = "conlyopt",
    allowMultiple = true,
    defaultValue = "",
    category = "flags",
    help = "Additional option to pass to gcc when compiling C source files."
  )
  public List<String> conlyoptList;

  @Option(
    name = "linkopt",
    defaultValue = "",
    category = "flags",
    allowMultiple = true,
    help = "Additional option to pass to gcc when linking."
  )
  public List<String> linkoptList;

  @Option(
    name = "ltoindexopt",
    defaultValue = "",
    category = "flags",
    allowMultiple = true,
    help = "Additional option to pass to the LTO indexing step (under --features=thin_lto)."
  )
  public List<String> ltoindexoptList;

  @Option(
    name = "stripopt",
    allowMultiple = true,
    defaultValue = "",
    category = "flags",
    help = "Additional options to pass to strip when generating a '<name>.stripped' binary."
  )
  public List<String> stripoptList;

  @Option(
    name = "custom_malloc",
    defaultValue = "null",
    category = "semantics",
    help =
        "Specifies a custom malloc implementation. This setting overrides malloc "
            + "attributes in build rules.",
    converter = LabelConverter.class
  )
  public Label customMalloc;

  @Option(
    name = "legacy_whole_archive",
    defaultValue = "true",
    category = "semantics",
    help =
        "When on, use --whole-archive for cc_binary rules that have "
            + "linkshared=1 and either linkstatic=1 or '-static' in linkopts. "
            + "This is for backwards compatibility only. "
            + "A better alternative is to use alwayslink=1 where required."
  )
  public boolean legacyWholeArchive;

  @Option(
    name = "strip",
    defaultValue = "sometimes",
    category = "flags",
    help =
        "Specifies whether to strip binaries and shared libraries "
            + " (using \"-Wl,--strip-debug\").  The default value of 'sometimes'"
            + " means strip iff --compilation_mode=fastbuild.",
    converter = StripModeConverter.class
  )
  public StripMode stripBinaries;

  @Option(
    name = "fdo_instrument",
    defaultValue = "null",
    converter = OptionsUtils.PathFragmentConverter.class,
    category = "flags",
    implicitRequirements = {"--copt=-Wno-error"},
    help =
        "Generate binaries with FDO instrumentation. Specify the relative "
            + "directory name for the .gcda files at runtime with GCC compiler. "
            + "With Clang/LLVM compiler, it also accepts the directory name under"
            + "which the raw profile file(s) will be dumped at runtime."
  )
  public PathFragment fdoInstrument;

  @Option(
    name = "fdo_optimize",
    defaultValue = "null",
    category = "flags",
    help =
        "Use FDO profile information to optimize compilation. Specify the name "
            + "of the zip file containing the .gcda file tree or an afdo file containing "
            + "an auto profile. This flag also accepts files specified as labels, for "
            + "example //foo/bar:file.afdo. Such labels must refer to input files; you may "
            + "need to add an exports_files directive to the corresponding package to make "
            + "the file visible to Blaze. It also accepts an indexed LLVM profile file."
  )
  public String fdoOptimize;

  @Option(
    name = "autofdo_lipo_data",
    defaultValue = "false",
    category = "flags",
    help =
        "If true then the directory name for non-LIPO targets will have a "
            + "'-lipodata' suffix in AutoFDO mode."
  )
  public boolean autoFdoLipoData;

  @Option(
    name = "lipo",
    defaultValue = "off",
    converter = LipoModeConverter.class,
    category = "flags",
    help =
        "Enable LIPO optimization (lightweight inter-procedural optimization, The allowed "
            + "values for  this option are 'off' and 'binary', which enables LIPO. This option "
            + "only has an effect when FDO is also enabled. Currently LIPO is only supported "
            + "when building a single cc_binary rule."
  )
  public LipoMode lipoMode;

  @Option(
    name = "lipo_context",
    defaultValue = "null",
    category = "flags",
    converter = LabelConverter.class,
    implicitRequirements = {"--linkopt=-Wl,--warn-unresolved-symbols"},
    help = "Specifies the binary from which the LIPO profile information comes."
  )
  public Label lipoContext;

  @Option(
    name = "experimental_stl",
    converter = LabelConverter.class,
    defaultValue = "null",
    category = "version",
    help =
        "If set, use this label instead of the default STL implementation. "
            + "This option is EXPERIMENTAL and may go away in a future release."
  )
  public Label stl;

  @Option(
    name = "save_temps",
    defaultValue = "false",
    category = "what",
    help =
        "If set, temporary outputs from gcc will be saved.  "
            + "These include .s files (assembler code), .i files (preprocessed C) and "
            + ".ii files (preprocessed C++)."
  )
  public boolean saveTemps;

  @Option(
    name = "per_file_copt",
    allowMultiple = true,
    converter = PerLabelOptions.PerLabelOptionsConverter.class,
    defaultValue = "",
    category = "semantics",
    help =
        "Additional options to selectively pass to gcc when compiling certain files. "
            + "This option can be passed multiple times. "
            + "Syntax: regex_filter@option_1,option_2,...,option_n. Where regex_filter stands "
            + "for a list of include and exclude regular expression patterns (Also see "
            + "--instrumentation_filter). option_1 to option_n stand for "
            + "arbitrary command line options. If an option contains a comma it has to be "
            + "quoted with a backslash. Options can contain @. Only the first @ is used to "
            + "split the string. Example: "
            + "--per_file_copt=//foo/.*\\.cc,-//foo/bar\\.cc@-O0 adds the -O0 "
            + "command line option to the gcc command line of all cc files in //foo/ "
            + "except bar.cc."
  )
  public List<PerLabelOptions> perFileCopts;

  @Option(
    name = "host_crosstool_top",
    defaultValue = "null",
    converter = LabelConverter.class,
    category = "semantics",
    help =
        "By default, the --crosstool_top and --compiler options are also used "
            + "for the host configuration. If this flag is provided, Blaze uses the default libc "
            + "and compiler for the given crosstool_top."
  )
  public Label hostCrosstoolTop;

  @Option(
    name = "host_copt",
    allowMultiple = true,
    defaultValue = "",
    category = "flags",
    help = "Additional options to pass to gcc for host tools."
  )
  public List<String> hostCoptList;

  @Option(
    name = "grte_top",
    defaultValue = "null", // The default value is chosen by the toolchain.
    category = "version",
    converter = LibcTopConverter.class,
    help =
        "A label to a checked-in libc library. The default value is selected by the crosstool "
            + "toolchain, and you almost never need to override it."
  )
  public LibcTop libcTop;

  @Option(
    name = "host_grte_top",
    defaultValue = "null", // The default value is chosen by the toolchain.
    category = "version",
    converter = LibcTopConverter.class,
    help =
        "If specified, this setting overrides the libc top-level directory (--grte_top) "
            + "for the host configuration."
  )
  public LibcTop hostLibcTop;

  @Option(
    name = "output_symbol_counts",
    defaultValue = "false",
    category = "flags",
    help =
        "If enabled, every C++ binary linked with gold will store the number of used "
            + "symbols per object file in a .sc file."
  )
  public boolean symbolCounts;

  @Option(
    name = "experimental_inmemory_dotd_files",
    defaultValue = "false",
    category = "experimental",
    help =
        "If enabled, C++ .d files will be passed through in memory directly from the remote "
            + "build nodes instead of being written to disk."
  )
  public boolean inmemoryDotdFiles;

  @Option(
    name = "experimental_skip_unused_modules",
    defaultValue = "false",
    category = "experimental",
    help = "Deprecated. No effect."
  )
  public boolean skipUnusedModules;

  @Option(
    name = "experimental_prune_more_modules",
    defaultValue = "false",
    category = "experimental",
    help = "Deprecated. No effect."
  )
  public boolean pruneMoreModules;

  @Option(
    name = "prune_cpp_modules",
    defaultValue = "true",
    category = "strategy",
    help = "If enabled, use the results of input discovery to reduce the number of used modules."
  )
  public boolean pruneCppModules;

  @Option(
    name = "experimental_omitfp",
    defaultValue = "false",
    category = "semantics",
    help =
        "If true, use libunwind for stack unwinding, and compile with "
            + "-fomit-frame-pointer and -fasynchronous-unwind-tables."
  )
  public boolean experimentalOmitfp;

  @Option(
    name = "share_native_deps",
    defaultValue = "true",
    category = "strategy",
    help =
        "If true, native libraries that contain identical functionality "
            + "will be shared among different targets"
  )
  public boolean shareNativeDeps;

  @Option(
    name = "strict_system_includes",
    defaultValue = "false",
    category = "strategy",
    help =
        "If true, headers found through system include paths (-isystem) are also required to be "
        + "declared."
  )
  public boolean strictSystemIncludes;

  @Override
  public FragmentOptions getHost(boolean fallback) {
    CppOptions host = (CppOptions) getDefault();

    // The crosstool options are partially copied from the target configuration.
    if (!fallback) {
      if (hostCrosstoolTop == null) {
        host.cppCompiler = cppCompiler;
        host.crosstoolTop = crosstoolTop;
        host.glibc = glibc;
      } else {
        host.crosstoolTop = hostCrosstoolTop;
      }
    }

    // hostLibcTop doesn't default to the target's libcTop.
    // Only an explicit command-line option will change it.
    // The default is whatever the host's crosstool (which might have been specified
    // by --host_crosstool_top, or --crosstool_top as a fallback) says it should be.
    host.libcTop = hostLibcTop;

    // -g0 is the default, but allowMultiple options cannot have default values so we just pass
    // -g0 first and let the user options override it.
    host.coptList = ImmutableList.<String>builder().add("-g0").addAll(hostCoptList).build();

    host.useStartEndLib = useStartEndLib;
    host.stripBinaries = StripMode.ALWAYS;
    host.fdoOptimize = null;
    host.lipoMode = LipoMode.OFF;
    host.inmemoryDotdFiles = inmemoryDotdFiles;

    return host;
  }

  @Override
  public void addAllLabels(Multimap<String, Label> labelMap) {
    labelMap.put("crosstool", crosstoolTop);
    if (hostCrosstoolTop != null) {
      labelMap.put("crosstool", hostCrosstoolTop);
    }

    if (libcTop != null) {
      Label libcLabel = libcTop.getLabel();
      if (libcLabel != null) {
        labelMap.put("crosstool", libcLabel);
      }
    }
    if (hostLibcTop != null) {
      Label libcLabel = hostLibcTop.getLabel();
      if (libcLabel != null) {
        labelMap.put("crosstool", libcLabel);
      }
    }
    addOptionalLabel(labelMap, "fdo", fdoOptimize);

    if (stl != null) {
      labelMap.put("STL", stl);
    }

    if (customMalloc != null) {
      labelMap.put("custom_malloc", customMalloc);
    }

    if (getLipoContextLabel() != null) {
      labelMap.put("lipo", getLipoContextLabel());
    }
  }

  @Override
  public Map<String, Set<Label>> getDefaultsLabels(BuildConfiguration.Options commonOptions) {
    Set<Label> crosstoolLabels = new LinkedHashSet<>();
    crosstoolLabels.add(crosstoolTop);
    if (hostCrosstoolTop != null) {
      crosstoolLabels.add(hostCrosstoolTop);
    }

    if (libcTop != null) {
      Label libcLabel = libcTop.getLabel();
      if (libcLabel != null) {
        crosstoolLabels.add(libcLabel);
      }
    }

    return ImmutableMap.of("CROSSTOOL", crosstoolLabels, "COVERAGE", ImmutableSet.<Label>of());
  }

  public boolean isFdo() {
    return fdoOptimize != null || fdoInstrument != null;
  }

  public boolean isLipoOptimization() {
    return lipoMode == LipoMode.BINARY && fdoOptimize != null && lipoContext != null;
  }

  public boolean isLipoOptimizationOrInstrumentation() {
    return lipoMode == LipoMode.BINARY
        && ((fdoOptimize != null && lipoContext != null) || fdoInstrument != null);
  }

  public Label getLipoContextLabel() {
    return (lipoMode == LipoMode.BINARY && fdoOptimize != null) ? lipoContext : null;
  }

  public LipoMode getLipoMode() {
    return lipoMode;
  }

  /**
   * FDO/LIPO is not yet compatible with dynamic configurations.
   **/
  @Override
  public boolean useStaticConfigurationsOverride() {
    // --lipo=binary is technically possible without FDO, even though it doesn't do anything.
    return isFdo() || getLipoMode() == LipoMode.BINARY;
  }

}
