// 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.
//
// File format for Blaze to configure Crosstool releases.

syntax = "proto2";

// option java_api_version = 2;
option java_package = "com.google.devtools.build.lib.view.config.crosstool";

// option py_api_version = 2;

package com.google.devtools.build.lib.view.config.crosstool;

// A description of a toolchain, which includes all the tools generally expected
// to be available for building C/C++ targets, based on the GNU C compiler.
//
// System and cpu names are two overlapping concepts, which need to be both
// supported at this time. The cpu name is the blaze command-line name for the
// target system. The most common values are 'k8' and 'piii'. The system name is
// a more generic identification of the executable system, based on the names
// used by the GNU C compiler.
//
// Typically, the system name contains an identifier for the cpu (e.g. x86_64 or
// alpha), an identifier for the machine (e.g. pc, or unknown), and an
// identifier for the operating system (e.g. cygwin or linux-gnu). Typical
// examples are 'x86_64-unknown-linux-gnu' and 'i686-unknown-cygwin'.
//
// The system name is used to determine if a given machine can execute a given
// exectuable. In particular, it is used to check if the compilation products of
// a toolchain can run on the host machine.
message CToolchain {
  // Optional flag. Some option lists have a corresponding optional flag list.
  // These are appended at the end of the option list in case the corresponding
  // default setting is set.
  message OptionalFlag {
    required string default_setting_name = 1;
    repeated string flag = 2;
  }

  // A group of correlated flags. Supports parametrization via variable
  // expansion.
  //
  // To expand a variable of list type, flag_group has to be annotated with
  // `iterate_over` message. Then all nested flags or flag_groups will be
  // expanded repeatedly for each element of the list.
  //
  // For example:
  // flag_group {
  //   iterate_over: 'include_path'
  //   flag: '-I'
  //   flag: '%{include_path}'
  // }
  // ... will get expanded to -I /to/path1 -I /to/path2 ... for each
  // include_path /to/pathN.
  //
  // To expand a variable of structure type, use dot-notation, e.g.:
  //    flag_group {
  //      iterate_over: "libraries_to_link"
  //      flag_group {
  //        iterate_over: "libraries_to_link.libraries"
  //        flag: "-L%{libraries_to_link.libraries.directory}"
  //      }
  //    }
  //
  // Flag groups can be nested; if they are, the flag group must only contain
  // other flag groups (no flags) so the order is unambiguously specified.
  // In order to expand a variable of nested lists, 'iterate_over' can be used.
  //
  // For example:
  // flag_group {
  //   iterate_over: 'object_files'
  //   flag_group { flag: '--start-lib' }
  //   flag_group {
  //     iterate_over: 'object_files'
  //     flag: '%{object_files}'
  //   }
  //   flag_group { flag: '--end-lib' }
  // }
  // ... will get expanded to
  //   --start-lib a1.o a2.o ... --end-lib --start-lib b1.o b2.o .. --end-lib
  //   with %{object_files} being a variable of nested list type
  //   [['a1.o', 'a2.o', ...], ['b1.o', 'b2.o', ...], ...].
  //
  // TODO(bazel-team): Write more elaborate documentation and add a link to it.
  message FlagGroup {
    repeated string flag = 1;

    repeated FlagGroup flag_group = 2;

    optional string iterate_over = 3;

    repeated string expand_if_all_available = 4;

    repeated string expand_if_none_available = 5;

    optional string expand_if_true = 6;

    optional string expand_if_false = 7;

    optional VariableWithValue expand_if_equal = 8;
  }

  message VariableWithValue {
    required string variable = 1;

    required string value = 2;
  }

  // A key/value pair to be added as an environment variable. The value of
  // this pair is expanded in the same way as is described in FlagGroup.
  // The key remains an unexpanded string literal.
  message EnvEntry {
    required string key = 1;
    required string value = 2;
  }

  // A set of features; used to support logical 'and' when specifying feature
  // requirements in FlagSet and Feature.
  message FeatureSet {
    repeated string feature = 1;
  }

  // A set of flags that are expanded in the command line for specific actions.
  message FlagSet {
    // The actions this flag set applies to; each flag set must specify at
    // least one action.
    repeated string action = 1;

    // The flags applied via this flag set.
    repeated FlagGroup flag_group = 2;

    // A list of feature sets defining when this flag set gets applied.  The
    // flag set will be applied when any of the feature sets fully apply, that
    // is, when all features of the feature set are enabled.
    //
    // If 'with_feature' is omitted, the flag set will be applied
    // unconditionally for every action specified.
    repeated FeatureSet with_feature = 3;

    // A list of build variables that this feature set needs, but which are
    // allowed to not be set. If any of the build variables listed is not
    // set, the feature set will not be expanded.
    //
    // NOTE: Consider alternatives before using this; usually tools should
    // consistently create the same set of files, even if empty; use this
    // only for backwards compatibility with already existing behavior in tools
    // that are currently not worth changing.
    repeated string expand_if_all_available = 4;
  }

  // A set of environment variables that are expanded in the command line for
  // specific actions.
  message EnvSet {
    // The actions this env set applies to; each env set must specify at
    // least one action.
    repeated string action = 1;

    // The environment variables applied via this env set.
    repeated EnvEntry env_entry = 2;

    // A list of feature sets defining when this env set gets applied.  The
    // env set will be applied when any of the feature sets fully apply, that
    // is, when all features of the feature set are enabled.
    //
    // If 'with_feature' is omitted, the env set will be applied
    // unconditionally for every action specified.
    repeated FeatureSet with_feature = 3;
  }

  // Contains all flag specifications for one feature.
  // Next ID: 8
  message Feature {
    // The feature's name. Feature names are generally defined by Bazel; it is
    // possible to introduce a feature without a change to Bazel by adding a
    // 'feature' section to the toolchain and adding the corresponding string as
    // feature in the BUILD file.
    optional string name = 1;

    // If 'true', this feature is enabled unless a rule type explicitly marks it
    // as unsupported. Such features cannot be turned off from within a BUILD
    // file or the command line.
    optional bool enabled = 7;

    // If the given feature is enabled, the flag sets will be applied for the
    // actions in the modes that they are specified for.
    repeated FlagSet flag_set = 2;

    // If the given feature is enabled, the env sets will be applied for the
    // actions in the modes that they are specified for.
    repeated EnvSet env_set = 6;

    // A list of feature sets defining when this feature is supported by the
    // toolchain. The feature is supported if any of the feature sets fully
    // apply, that is, when all features of a feature set are enabled.
    //
    // If 'requires' is omitted, the feature is supported independently of which
    // other features are enabled.
    //
    // Use this for example to filter flags depending on the build mode
    // enabled (opt / fastbuild / dbg).
    repeated FeatureSet requires = 3;

    // A list of features or action configs that are automatically enabled when
    // this feature is enabled. If any of the implied features or action configs
    // cannot be enabled, this feature will (silently) not be enabled either.
    repeated string implies = 4;

    // A list of names this feature conflicts with.
    // A feature cannot be enabled if:
    // - 'provides' contains the name of a different feature or action config
    //  that we want to enable.
    // - 'provides' contains the same value as a 'provides' in a different
    //   feature or action config that we want to enable.
    //
    // Use this in order to ensure that incompatible features cannot be
    // accidentally activated at the same time, leading to hard to diagnose
    // compiler errors.
    repeated string provides = 5;
  }

  // Describes a tool associated with a crosstool action config.
  message Tool {
    // Path to the tool, relative to the location of the crosstool.
    required string tool_path = 1;

    // A feature set defining when this tool is applicable.  If this attribute
    // is left out, the Tool will be assumed to apply for any feature
    // configuration.
    optional FeatureSet with_feature = 2;

    // Requirements on the execution environment for the execution of this tool,
    // to be passed as out-of-band "hints" to the execution backend.
    // Ex. "requires-darwin"
    repeated string execution_requirement = 3;
  }

  // The name for an artifact of a given category of input or output artifacts
  // to an action.
  message ArtifactNamePattern {
    // The category of artifacts that this selection applies to.  This field
    // is compared against a list of categories defined in bazel. Example
    // categories include "linked_output" or "debug_symbols". An error is thrown
    // if no category is matched.
    required string category_name = 1;
    // The pattern for creating the artifact for this selection.  The given
    // pattern is templated by bazel and then used to create an artifact in
    // a target-specific directory in bazel-bin.
    required string pattern = 2;
  }

  // An action config corresponds to a blaze action, and allows selection of
  // a tool based on activated features.  Action configs come in two varieties:
  // automatic (the blaze action will exist whether or not the action config
  // is activated) and attachable (the blaze action will be added to the
  // action graph only if the action config is activated).
  //
  // Action config activation occurs by the same semantics as features: a
  // feature can 'require' or 'imply' an action config in the same way that it
  // would another feature.
  // Next ID: 8
  message ActionConfig {
    // The name other features will use to activate this action config.  Can
    // be the same as action_name.
    required string config_name = 1;

    // The name of the blaze action that this config applies to, ex. 'c-compile'
    // or 'c-module-compile'.
    required string action_name = 2;

    // The tool applied to the action will be the first Tool with a feature
    // set that matches the feature configuration.  An error will be thrown
    // if no tool matches a provided feature configuration - for that reason,
    // it's a good idea to provide a default tool with an empty feature set.
    repeated Tool tool = 3;

    // If the given action config is enabled, the flag sets will be applied
    // to the corresponding action.
    repeated FlagSet flag_set = 4;

    // If the given action config is enabled, the env sets will be applied
    // to the corresponding action.
    repeated EnvSet env_set = 5;

    // A list of feature sets defining when this action config
    // is supported by the toolchain. The action config is supported if any of
    // the feature sets fully apply, that is, when all features of a
    // feature set are enabled.
    //
    // If 'requires' is omitted, the action config is supported independently
    // of which other features are enabled.
    //
    // Use this for example to filter actions depending on the build
    // mode enabled (opt / fastbuild / dbg).
    repeated FeatureSet requires = 6;

    // A list of features or action configs that are automatically enabled when
    // this action config is enabled. If any of the implied features or action
    // configs cannot be enabled, this action config will (silently)
    // not be enabled either.
    repeated string implies = 7;
  }

  repeated Feature feature = 50;
  repeated ActionConfig action_config = 53;
  repeated ArtifactNamePattern artifact_name_pattern = 54;

  // The unique identifier of the toolchain within the crosstool release. It
  // must be possible to use this as a directory name in a path.
  // It has to match the following regex: [a-zA-Z_][\.\- \w]*
  required string toolchain_identifier = 1;

  // A basic toolchain description.
  required string host_system_name = 2;
  required string target_system_name = 3;
  required string target_cpu = 4;
  required string target_libc = 5;
  required string compiler = 6;

  required string abi_version = 7;
  required string abi_libc_version = 8;

  // Tool locations. Relative paths are resolved relative to the configuration
  // file directory.
  // NOTE: DEPRECATED. Prefer specifying an ActionConfig for the action that
  // needs the tool.
  // TODO(b/27903698) migrate to ActionConfig.
  repeated ToolPath tool_path = 9;

  // Feature flags.
  // TODO(bazel-team): Sink those into 'Feature' instances.
  optional bool supports_gold_linker = 10 [default = false];
  // Legacy field, ignored by Bazel.
  optional bool supports_thin_archives = 11 [default = false];
  optional bool supports_start_end_lib = 28 [default = false];
  optional bool supports_interface_shared_objects = 32 [default = false];
  optional bool supports_embedded_runtimes = 40 [default = false];
  // If specified, Blaze finds statically linked / dynamically linked runtime
  // libraries in the declared crosstool filegroup. Otherwise, Blaze
  // looks in "[static|dynamic]-runtime-libs-$TARGET_CPU".
  optional string static_runtimes_filegroup = 45;
  optional string dynamic_runtimes_filegroup = 46;
  optional bool supports_incremental_linker = 41 [default = false];
  // This should be true, if the toolchain supports the D flag to ar, which
  // makes it output normalized archives that don't contain timestamps.
  optional bool supports_normalizing_ar = 26 [default = false];
  optional bool supports_fission = 43 [default = false];
  // Can generate dsym debug symbol information.
  optional bool supports_dsym = 51 [default = false];
  optional bool needsPic = 12 [default = false];

  // Compiler flags for C/C++/Asm compilation.
  repeated string compiler_flag = 13;
  repeated OptionalFlag optional_compiler_flag = 35;
  // Additional compiler flags for C++ compilation.
  repeated string cxx_flag = 14;
  repeated OptionalFlag optional_cxx_flag = 36;
  // Additional unfiltered compiler flags for C/C++/Asm compilation.
  // These are not subject to nocopt filtering in cc_* rules.
  // Note: These flags are *not* applied to objc/objc++ compiles.
  repeated string unfiltered_cxx_flag = 25;
  repeated OptionalFlag optional_unfiltered_cxx_flag = 37;
  // Linker flags.
  repeated string linker_flag = 15;
  repeated OptionalFlag optional_linker_flag = 38;
  // Additional linker flags when linking dynamic libraries.
  repeated string dynamic_library_linker_flag = 27;
  repeated OptionalFlag optional_dynamic_library_linker_flag = 39;
  // Additional test-only linker flags.
  repeated string test_only_linker_flag = 49;
  // Objcopy flags for embedding files into binaries.
  repeated string objcopy_embed_flag = 16;
  // Ld flags for embedding files into binaries. This is used by filewrapper
  // since it calls ld directly and needs to know what -m flag to pass.
  repeated string ld_embed_flag = 23;
  // Ar flags for combining object files into archives. If this is not set, it
  // defaults to "rcsD".
  // TODO(b/37271982): Remove after blaze with ar action_config release
  repeated string ar_flag = 47;
  // Legacy field, ignored by Bazel.
  repeated string ar_thin_archives_flag = 48;
  // Additional compiler flags that are added for cc_plugin rules of type 'gcc'
  repeated string gcc_plugin_compiler_flag = 34;

  // Additional compiler and linker flags depending on the compilation mode.
  repeated CompilationModeFlags compilation_mode_flags = 17;

  // Additional compiler and linker flags depending on the LIPO mode.
  repeated LipoModeFlags lipo_mode_flags = 44;

  // Additional linker flags depending on the linking mode.
  repeated LinkingModeFlags linking_mode_flags = 18;

  // Plugin header directories for gcc and mao plugins. If none are set, the
  // toolchain does not support plugins. Relative paths are resolved relative
  // to the configuration file directory.
  repeated string gcc_plugin_header_directory = 19;
  repeated string mao_plugin_header_directory = 20;

  // Make variables that are made accessible to rules.
  repeated MakeVariable make_variable = 21;

  // Built-in include directories for C++ compilation. These should be the exact
  // paths used by the compiler, and are generally relative to the exec root.
  // The paths used by the compiler can be determined by 'gcc -Wp,-v some.c'.
  // We currently use the C++ paths also for C compilation, which is safe as
  // long as there are no name clashes between C++ and C header files.
  //
  // Relative paths are resolved relative to the configuration file directory.
  //
  // If the compiler has --sysroot support, then these paths should use
  // %sysroot% rather than the include path, and specify the sysroot attribute
  // in order to give blaze the information necessary to make the correct
  // replacements.
  repeated string cxx_builtin_include_directory = 22;

  // The built-in sysroot. If this attribute is not present, blaze does not
  // allow using a different sysroot, i.e. through the --grte_top option. Also
  // see the documentation above.
  optional string builtin_sysroot = 24;

  // The location and version of the default Python (in absence of
  // --python_top and --python_version, respectively. The default
  // --python_mode is always 'opt'.) For backward compatibility, if these
  // attributes are not set, Blaze will use the crosstool v11-13 default
  // values: "/usr/grte/v1" and "python2.4".
  optional string default_python_top = 29;
  optional string default_python_version = 30;
  // Whether to preload swigdeps.so files in py_binaries and PAR files.
  // This overrides the commandline flag.
  optional bool python_preload_swigdeps = 42;

  // The default GRTE to use. This should be a label, and gets the same
  // treatment from Blaze as the --grte_top option. This setting is only used in
  // the absence of an explicit --grte_top option. If unset, Blaze will not pass
  // -sysroot by default. The local part must be 'everything', i.e.,
  // '//some/label:everything'. There can only be one GRTE library per package,
  // because the compiler expects the directory as a parameter of the -sysroot
  // option.
  // This may only be set to a non-empty value if builtin_sysroot is also set!
  optional string default_grte_top = 31;

  // Additional dependencies for Blaze-built .deb packages. All Debian packages
  // that contain C++ binaries need to have the correct runtime
  // libraries installed, and those depend on the crosstool version, which is
  // why they are recorded here.
  repeated string debian_extra_requires = 33;

  // Unused, for compatibility with things internal to Google.
  optional string cc_target_os = 55;

  // Next free id: 56
}

message ToolPath {
  required string name = 1;
  required string path = 2;
}

enum CompilationMode {
  FASTBUILD = 1;
  DBG = 2;
  OPT = 3;
  // This value is ignored and should not be used in new files.
  COVERAGE = 4;
}

message CompilationModeFlags {
  required CompilationMode mode = 1;
  repeated string compiler_flag = 2;
  repeated string cxx_flag = 3;
  // Linker flags that are added when compiling in a certain mode.
  repeated string linker_flag = 4;
}

enum LinkingMode {
  FULLY_STATIC = 1;
  MOSTLY_STATIC = 2;
  DYNAMIC = 3;
  MOSTLY_STATIC_LIBRARIES = 4;
}

message LinkingModeFlags {
  required LinkingMode mode = 1;
  repeated string linker_flag = 2;
}

enum LipoMode {
  OFF = 1;
  BINARY = 2;
  // LIBRARY = 3;  // RESERVED
}

message LipoModeFlags {
  required LipoMode mode = 1;
  repeated string compiler_flag = 2;
  repeated string cxx_flag = 3;
  repeated string linker_flag = 4;
}

message MakeVariable {
  required string name = 1;
  required string value = 2;
}

message DefaultCpuToolchain {
  required string cpu = 1;
  required string toolchain_identifier = 2;
  optional bool supports_lipo = 3 [default = true];
}

// An entire crosstool release, containing the version number, a default target
// cpu, a default toolchain for each supported cpu type, and a set of
// toolchains.
message CrosstoolRelease {
  message DefaultSetting {
    required string name = 1;
    required bool default_value = 2;
  }

  // The major and minor version of the crosstool release.
  required string major_version = 1;
  required string minor_version = 2;

  // Deprecated. Used to be the default CPU if not otherwise specified, but it's
  // not used for that purpose (or anything else) anymore. Please also don't add
  // new uses of this field.
  required string default_target_cpu = 3;
  // The default toolchain to use for each given cpu.
  repeated DefaultCpuToolchain default_toolchain = 4;

  // The default settings used in this release.
  repeated DefaultSetting default_setting = 6;

  // All the toolchains in this release.
  repeated CToolchain toolchain = 5;
}