0f1507af41
Few printf config options have been setup using this new config system along with their baremetal overrides. A follow up patch will add generation of doc/config.rst, which will contain the full list of libc config options and short description explaining how they affect the libc. Reviewed By: gchatelet Differential Revision: https://reviews.llvm.org/D159158
138 lines
5.7 KiB
CMake
138 lines
5.7 KiB
CMake
# This cmake module contains utilities to read and load libc config options
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# listed in config.json files.
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#
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# The JSON parsing commands that CMake provides are rather tedious to use.
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# Below is a quick reference which tries to map the CMake JSON parsing
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# commands to the Python dictionary API.
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#
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# * There is no way to iterate over the JSON items. One will first
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# have to find the number of items using string(JSON ... LENGTH ...)
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# command, and then iterate over the items using foreach(... RANGE ...).
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# * The way to get the key from the JSON dictionary is to use the index
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# of the item and the string(JSON ... MEMBER ... $<index>) function.
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# * Once you have the key, you can use the string(JSON ... GET ... $<key>)
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# function to get the value corresponding to the key.
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# Fill |opt_list| with all options listed in |config_file|. For each option,
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# the item added to |opt_list| is the dictionary of the form:
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# {
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# "<option name>": {
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# "value: <option value>,
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# "doc": "<option doc string>",
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# }
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# }
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# Each of the above items can be parsed again with the string(JSON ...)
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# command.
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# This function does nothing if |config_file| is missing.
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function(read_libc_config config_file opt_list)
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if(NOT EXISTS ${config_file})
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return()
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endif()
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# We will assume that a config file is loaded only once and that
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# each config file loaded will affect config information. Since
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# we want a change to config information to trigger reconfiguration,
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# we add the |config_file| to the list of files the configure itself
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# should depend on.
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set_property(
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DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
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PROPERTY CMAKE_CONFIGURE_DEPENDS ${config_file})
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file(READ ${config_file} json_config)
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string(JSON group_count ERROR_VARIABLE json_error LENGTH ${json_config})
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if(json_error)
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message(FATAL_ERROR "${config_file}: ${json_error}")
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endif()
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if(${group_count} EQUAL 0)
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# This "if" conditions becomes active if there are no config options
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# to load. If there are no config options, it is better to remove that
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# config.json file instead of including an empty file.
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message(FATAL_ERROR "${config_file}: Does not contain any config option groups")
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return()
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endif()
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math(EXPR group_count_1 "${group_count} - 1")
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set(optname_list)
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foreach(group_num RANGE ${group_count_1})
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# The group names are the keys of the global dictionary. So, we first
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# lookup the group name or the key for each item in the dictionary.
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string(JSON group_name ERROR_VARIABLE json_error MEMBER ${json_config} ${group_num})
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if(json_error)
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message(FATAL_ERROR "${config_file}: ${json_error}")
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endif()
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# Once we have the group name, we GET the option map for that group, which
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# is the value corresponding to the group name key.
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string(JSON option_map ERROR_VARIABLE json_error GET ${json_config} ${group_name})
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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string(JSON option_count ERROR_VARIABLE jsor_error LENGTH ${option_map})
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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if(${option_count} EQUAL 0)
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message(FATAL_ERROR "${config_file}: No options listed against the config option group '${group_name}'")
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endif()
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math(EXPR option_count_1 "${option_count} - 1")
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foreach(opt_num RANGE ${option_count_1})
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string(JSON option_name ERROR_VARIABLE json_error MEMBER ${option_map} ${opt_num})
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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list(FIND optname_list ${option_name} optname_exists)
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if(${optname_exists} GREATER -1)
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message(FATAL_ERROR "${config_file}: Found duplicate option name: ${option_name}")
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endif()
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list(APPEND optname_list ${option_name})
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string(JSON optdata ERROR_VARIABLE json_error GET ${option_map} ${option_name})
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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set(opt "{\"${option_name}\": ${optdata}}")
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list(APPEND all_opts ${opt})
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endforeach()
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endforeach()
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set(${opt_list} ${all_opts} PARENT_SCOPE)
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endfunction()
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# Loads the config options listed in |config_file| in the following way:
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# * For each option listed in the |config_file|, it looks for existence of a
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# var with the same name. It is an error if the var is not already defined.
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# If a var with the option name is found, then its value is overwritten
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# with the value specified in |config_file|.
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# * If there are options which are not to be overriden, then the list of
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# such options can be passed to this function after the |config_file|
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# argument. Typically, these will be the options specified on the CMake
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# command line.
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function(load_libc_config config_file)
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read_libc_config(${config_file} file_opts)
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foreach(opt IN LISTS file_opts)
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string(JSON opt_name ERROR_VARIABLE json_error MEMBER ${opt} 0)
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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if(NOT DEFINED ${opt_name})
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message(FATAL_ERROR: " Option ${opt_name} defined in ${config_file} is invalid.")
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endif()
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if(ARGN)
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list(FIND ARGN ${opt_name} optname_exists)
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if(${optname_exists} GREATER -1)
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# This option is not to be overridden so just skip further processing.
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continue()
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endif()
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endif()
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string(JSON opt_object ERROR_VARIABLE json_error GET ${opt} ${opt_name})
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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string(JSON opt_value ERROR_VARIABLE jsor_error GET ${opt_object} "value")
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if(json_error)
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message(FATAL_ERROR ${json_error})
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endif()
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message(STATUS "Overriding - ${opt_name}: ${opt_value} (Previous value: ${${opt_name}})")
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set(${opt_name} ${opt_value} PARENT_SCOPE)
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endforeach()
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endfunction()
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