Collecting Information about GCC Warnings

Overview

The purpose of this tool is to provide information about GCC warnings not enabled by default, nor by using some other warning option, such as -Wall, -Wextra or -Wpedantic. The goal is to show which warnings could be useful to explicitly enable in the C++ projects already using all the usual "maximum" warning options.

You can see the results of running the script for gcc versions up to 11.1 online:

1. Here are the warnings not enabled by another warning option.
2. And here is the table with all gcc warnings.

Requirements

• Raku v6.d.
• Git clone of gcc repository is required. The directory containing it is called $GCC_DIR in the instructions below.
• The scripts here work in Unix-like environment. They might work under Cygwin or MSYS2, but were only tested under Linux.

Operation

Run ./show-gcc-warnings $GCC_DIR > warnings.csv to generate the CSV file containing all warnings not enabled by default or by one of the common warning options and the minimum version in which they appeared (note that 4.6.0 means that the warning was already present in gcc 4.6.0, not necessarily that it was introduced in this version). With --all option, all warnings are included and the extra "Enabled by" column is added to show the condition enabling the warning.

If JSON::Fast Raku module is available, specify --json option to obtain output in JSON format.

Alternatively, use --cpp option to generate C++ fragment, which can be included in the source of a program that needs to do something (e.g. turn on) all the warnings.

Finally, --markdown option can be used to generate a Markdown table with the options.

If --dump-all-to option is given, output files named x.y.z for all gcc releases since 4.6.0 containing all (not enabled by default) warnings available in the given compiler version will be created under the specified output directory $OUT_DIR. The existing files in this directory will not be overwritten. Further specifying --only-version=x.y.z[,x2.y2.z2...] will restrict the output to the specified version(s) only. These files can be used on their own, and can also be reused by specifing --read-from option with the same directory later when running in the default mode.

The helper dump-gcc-warnings script can be used to produce more detailed output, including the warnings enabled by default, if --all option is specified, for a particular gcc version, by passing it common.opt and c-family/c.opt files from gcc source tree as command line parameters.

Note that, for convenience, output of the scripts for all gcc versions up to the latest tested one (currently 11.1) are provided directly in this repository, see warnings.{cpp,csv,json} files and gcc and gcc-all directories, containing per-directory warnings lists.