bazel选项的部分翻译，希望给编译tf的童鞋参考

Posted 2022-12-14 xizero00

（1）bazel的选项解释

The following sections describe the options available during a build. When --long is used on a help command, the on-line help messages provide summary information about the meaning, type and default value for each option.

Most options can only be specified once. When specified multiple times, the last instance wins. Options that can be specified multiple times are identified in the on-line help with the text 'may be used multiple times'. 可以使用 bazel --long打印出所有的选项，大多数选项只可以指定一次，当指定多次时，最后一次的指定才算数。可以指定多次的选项可以在帮助中看到：即说明该选项可以被指定多次。
1）指定包的位置的选项 See also the  --show_package_location  option.

--package_path

This option specifies the set of directories that are searched to find the BUILD file for a given package. 该选项指定搜索BUILD文件的目录集合

--deleted_packages

This option specifies a comma-separated list of packages which Bazel should consider deleted, and not attempt to load from any directory on the package path. This can be used to simulate the deletion of packages without actually deleting them. 该选项以逗号为分隔符来指定那些包bazel需要忽略，这个选项并不是真的删除包，而是忽略某个或者某些包
2）错误检查选项

Error checking options

These options control Bazel's error-checking and/or warnings. 错误检查选项，该选项控制bazel的错误检查或者告警信息

--check_constraint constraint 该选项的输入指定那些限制应该被检查，bazel将会对每个规则执行特别的检查，支持的限制包括public This option takes an argument that specifies which constraint should be checked.

Bazel performs special checks on each rule that is annotated with the given constraint.

The supported constraints and their checks are as follows:

• public: Verify that all java_libraries marked with constraints = ['public'] only depend on java_libraries that are marked as constraints = ['public'] too. If bazel finds a dependency that does not conform to this rule, bazel will issue an error.

--[no]check_visibility

If this option is set to false, visibility checks are demoted to warnings. The default value of this option is true, so that by default, visibility checking is done. 该选择如果设置为false，则不会告警，默认是true，需要检查可见性

--experimental_action_listener=label 

The experimental_action_listener option instructs Bazel to use details from the action_listener rule specified by label to insert extra_actions into the build graph.

--experimental_extra_action_filter=regex 

The experimental_extra_action_filter option instructs Bazel to filter the set of targets to schedule extra_actions for.

This flag is only applicable in combination with the --experimental_action_listener flag.

By default all extra_actions in the transitive closure of the requested targets-to-build get scheduled for execution. --experimental_extra_action_filter will restrict scheduling to extra_actions of which the owner's label matches the specified regular expression.

The following example will limit scheduling of extra_actions to only apply to actions of which the owner's label contains '/bar/':

% bazel build --experimental_action_listener=//test:al //foo/... \\
  --experimental_extra_action_filter=.*/bar/.*


--output_filter regex 该选项将会显示那些符合正则表达式的构建和编译的警告。如果目标不匹配则标准输出和标准错误将会被丢弃。该选项就是用于帮助找到某些特定的警告的 The  --output_filter option will only show build and compilation warnings for targets that match the regular expression. If a target does not match the given regular expression and its execution succeeds, its standard output and standard error are thrown away. This option is intended to be used to help focus efforts on fixing warnings in packages under development. Here are some typical values for this option: 下面是几个例子：

--output_filter=	Show all output.
--output_filter='^//(first/project|second/project):'	Show the output for the specified packages.
--output_filter='^//((?!(first/bad_project|second/bad_project):).)*$'	Don't show output for the specified packages.
--output_filter=DONT_MATCH_ANYTHING	Don't show output.

--[no]analysis_warnings_as_errors

When this option is enabled, visible analysis warnings (as specified by the output filter) are treated as errors, effectively preventing the build phase from starting. This feature can be used to enable strict builds that do not allow new warnings to creep into a project.

3）标志选项

Flags options

These options control which options Bazel will pass to other tools.

--copt gcc-option 该选项指定给gcc传递什么参数 This option takes an argument which is to be passed to gcc. The argument will be passed to gcc whenever gcc is invoked for preprocessing, compiling, and/or assembling C, C++, or assembler code. It will not be passed when linking. This option can be used multiple times. For example: 例子如下：

  % bazel build --copt="-g0" --copt="-fpic" //foo

will compile the foo library without debug tables, generating position-independent code.

Note that changing --copt settings will force a recompilation of all affected object files. Also note that copts values listed in specific cc_library or cc_binary build rules will be placed on the gcc command line after these options.

Warning: C++-specific options (such as -fno-implicit-templates) should be specified in --cxxopt, not in --copt. Likewise, C-specific options (such as -Wstrict-prototypes) should be specified in --conlyopt, not in copt. Similarly, gcc options that only have an effect at link time (such as -l) should be specified in --linkopt, not in --copt.

--host_copt gcc-option 该选项指定在host上进行编译时，给gcc在处理源码文件的时候需要传递给gcc的参数 This option takes an argument which is to be passed to gcc for source files that are compiled in the host configuration. This is analogous to the  --copt option, but applies only to the host configuration.

--conlyopt gcc-option

该选项在gcc编辑c文件的时候需要传递给gcc的参数 This option takes an argument which is to be passed to gcc when compiling C source files.

This is similar to --copt, but only applies to C compilation, not to C++ compilation or linking. So you can pass C-specific options (such as -Wno-pointer-sign) using --conlyopt.

Note that copts parameters listed in specific cc_library or cc_binary build rules will be placed on the gcc command line after these options.

--cxxopt gcc-option

该选项在gcc编辑c++文件的时候需要传递给gcc的参数 This option takes an argument which is to be passed to gcc when compiling C++ source files.

This is similar to --copt, but only applies to C++ compilation, not to C compilation or linking. So you can pass C++-specific options (such as -fpermissive or -fno-implicit-templates) using --cxxopt. For example:

  % bazel build --cxxopt="-fpermissive" --cxxopt="-Wno-error" //foo/cruddy_code

Note that copts parameters listed in specific cc_library or cc_binary build rules will be placed on the gcc command line after these options.

--linkopt linker-option 该选项在gcc进行链接的时候需要传递给gcc的参数 This option takes an argument which is to be passed to gcc when linking.

This is similar to --copt, but only applies to linking, not to compilation. So you can pass gcc options that only make sense at link time (such as -lssp or -Wl,--wrap,abort) using --linkopt. For example:

  % bazel build --copt="-fmudflap" --linkopt="-lmudflap" //foo/buggy_code

Build rules can also specify link options in their attributes. This option's settings always take precedence. Also seecc_library.linkopts.

--strip (always|never|sometimes)

该选项指定是否从二进制文件和共享库文件中去除调试信息 This option determines whether Bazel will strip debugging information from all binaries and shared libraries, by invoking the linker with the  -Wl,--strip-debug option.  --strip=always means always strip debugging information.  --strip=never means never strip debugging information. The default value of  --strip=sometimes means strip iff the  --compilation_mode is  fastbuild.

  % bazel build --strip=always //foo:bar

will compile the target while stripping debugging information from all generated binaries.

Note that if you want debugging information, it's not enough to disable stripping; you also need to make sure that the debugging information was generated by the compiler, which you can do by using either -c dbg or --copt -g.

Note also that Bazel's --strip option corresponds with ld's --strip-debug option: it only strips debugging information. If for some reason you want to strip all symbols, not just debug symbols, you would need to use ld's --strip-all option, which you can do by passing --linkopt=-Wl,--strip-all to Bazel.

--stripopt strip-option

An additional option to pass to the strip command when generating a *.stripped binary. The default is -S -p. This option can be used multiple times.

Note that --stripopt does not apply to the stripping of the main binary with --strip=(always|sometimes).

--fdo_instrument profile-output-dir

The --fdo_instrument option enables the generation of FDO (feedback directed optimization) profile output when the built C/C++ binary is executed. For GCC, the argument provided is used as a directory prefix for a per-object file directory tree of .gcda files containing profile information for each .o file.

Once the profile data tree has been generated, the profile tree should be zipped up, and provided to the --fdo_optimize=profile-zip Bazel option to enable the FDO optimized compilation.

For the LLVM compiler the argument is also the directory under which the raw LLVM profile data file(s) is dumped, e.g. --fdo_instrument=/path/to/rawprof/dir/.

The options --fdo_instrument and --fdo_optimize cannot be used at the same time.

--fdo_optimize profile-zip

The --fdo_optimize option enables the use of the per-object file profile information to perform FDO (feedback directed optimization) optimizations when compiling. For GCC, the argument provided is the zip file containing the previously-generated file tree of .gcda files containing profile information for each .o file.

Alternatively, the argument provided can point to an auto profile identified by the extension .afdo.

Note that this option also accepts labels that resolve to source files. You may need to add an exports_filesdirective to the corresponding package to make the file visible to Bazel.

For the LLVM compiler the argument provided should point to the indexed LLVM profile output file prepared by the llvm-profdata tool, and should have a .profdata extension.

The options --fdo_instrument and --fdo_optimize cannot be used at the same time.

--lipo (off|binary)

The --lipo=binary option enables LIPO (Lightweight Inter-Procedural Optimization). LIPO is an extended C/C++ optimization technique that optimizes code across different object files. It involves compiling each C/C++ source file differently for every binary. This is in contrast to normal compilation where compilation outputs are reused. This means that LIPO is more expensive than normal compilation.

This option only has an effect when FDO is also enabled (see the --fdo_instrument and --fdo_options). Currently LIPO is only supported when building a single cc_binary rule.

Setting --lipo=binary implicitly sets --dynamic_mode=off.

--lipo_context context-binary

Specifies the label of a cc_binary rule that was used to generate the profile information for LIPO that was given to the --fdo_optimize option.

Specifying the context is mandatory when --lipo=binary is set. Using this option implicitly also sets --linkopt=-Wl,--warn-unresolved-symbols.

--[no]output_symbol_counts

If enabled, each gold-invoked link of a C++ executable binary will also output a symbol counts file (via the --print-symbol-counts gold option) that logs the number of symbols from each .o input that were used in the binary. This can be used to track unnecessary link dependencies. The symbol counts file is written to the binary's output path with the name [targetname].sc.

This option is disabled by default.

--jvmopt jvm-option

传递给jvm的选项 This option allows option arguments to be passed to the Java VM. It can be used with one big argument, or multiple times with individual arguments. For example:

  % bazel build --jvmopt="-server -Xms256m" java/com/example/common/foo:all

will use the server VM for launching all Java binaries and set the startup heap size for the VM to 256 MB.

--javacopt javac-option

传递给javac的选项 This option allows option arguments to be passed to javac. It can be used with one big argument, or multiple times with individual arguments. For example:

  % bazel build --javacopt="-g:source,lines" //myprojects:prog

will rebuild a java_binary with the javac default debug info (instead of the bazel default).

The option is passed to javac after the Bazel built-in default options for javac and before the per-rule options. The last specification of any option to javac wins. The default options for javac are:

  -source 8 -target 8 -encoding UTF-8

Note that changing --javacopt settings will force a recompilation of all affected classes. Also note that javacopts parameters listed in specific java_library or java_binary build rules will be placed on the javac command line afterthese options.

-extra_checks[:(off|on)]

是否打开额外的正确性检查 This javac option enables extra correctness checks. Any problems found will be presented as errors. Either  -extra_checks or  -extra_checks:on may be used to force the checks to be turned on.  -extra_checks:offcompletely disables the analysis. When this option is not specified, the default behavior is used.

--strict_java_deps (default|strict|off|warn|error)

控制是否javac是否需要检查是否丢失直接的依赖 This option controls whether javac checks for missing direct dependencies. Java targets must explicitly declare all directly used targets as dependencies. This flag instructs javac to determine the jars actually used for type checking each java file, and warn/error if they are not the output of a direct dependency of the current target.

• off means checking is disabled.
• warn means javac will generate standard java warnings of type [strict] for each missing direct dependency.
• default, strict and error all mean javac will generate errors instead of warnings, causing the current target to fail to build if any missing direct dependencies are found. This is also the default behavior when the flag is unspecified.

--javawarn (all|cast|deprecation|empty|unchecked|fallthrough|path|rawtypes|serial|finally|overrides)

是否显示java在编译过程中的警告 This option is used to enable Java warnings across an entire build. It takes an argument which is a javac warning to be enabled, overriding any other Java options that disable the given warning. The arguments to this option are appended to the "-Xlint:" flag to javac, and must be exactly one of the listed warnings.

For example:

  % bazel build --javawarn="deprecation" --javawarn="unchecked" //java/...

Note that changing  --javawarn settings will force a recompilation of all affected classes.
4）语义选项

Semantics options

These options affect the build commands and/or the output file contents. 影响构建的命令和输出的内容
--compilation_mode (fastbuild|opt|dbg) (-c) 指定编译模式：快速编译还是调试还是最优化 This option takes an argument of  fastbuild,  dbg or  opt, and affects various C/C++ code-generation options, such as the level of optimization and the completeness of debug tables. Bazel uses a different output directory for each different compilation mode, so you can switch between modes without needing to do a full rebuild  every time.

• fastbuild means build as fast as possible: generate minimal debugging information (-gmlt -Wl,-S), and don't optimize. This is the default. Note: -DNDEBUG will not be set.
• dbg means build with debugging enabled (-g), so that you can use gdb (or another debugger).
• opt means build with optimization enabled and with assert() calls disabled (-O2 -DNDEBUG). Debugging information will not be generated in opt mode unless you also pass --copt -g.

--cpu cpu

指定目标gpu的架构 This option specifies the target CPU architecture to be used for the compilation of binaries during the build.

Note that a particular combination of crosstool version, compiler version, libc version, and target CPU is allowed only if it has been specified in the currently used CROSSTOOL file.

--host_cpu cpu 指定编译的机器的cpu架