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Ada is programming language designed for large, long-lived applications — and embedded systems in particular — where safety and security are essential.

Ada is used by a number of the packages in the Gentoo ebuild repository.


In this blog post of 2 June 2022, AdaCore announced "the end of the GNAT Community releases with 2021 being the last one. We encourage all GNAT Community users to transition to Alire going forward." However, this section nevertheless describes a Portage-based Ada setup based on installing the now-deprecated dev-lang/gnat-gpl package.

USE flags

USE flags for dev-lang/gnat-gpl GNAT Ada Compiler - GPL version

ada Build the ADA language (GNAT) frontend
bootstrap Used to bootstrap gnat-gpl
cet Enable support for Intel Control Flow Enforcement Technology (CET)
cxx Build support for C++ (bindings, extra libraries, code generation, ...)
d Enable support for the D programming language
debug Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see
default-stack-clash-protection Build packages with stack clash protection on by default
default-znow Request full relocation on start from by default
doc Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
fixed-point Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
fortran Add support for fortran
go Build the GCC Go language frontend.
graphite Add support for the framework for loop optimizations based on a polyhedral intermediate representation
hardened Activate default security enhancements for toolchain (gcc, glibc, binutils)
jit Enable just-in-time compilation for improved performance. May prevent use of some PaX memory protection features in Gentoo Hardened.
libssp Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
lto Enable Link-Time Optimization (LTO) to optimize the build
modula2 Build the GCC Modula-2 language frontend.
multilib On 64bit systems, if you want to be able to compile 32bit and 64bit binaries
nls Add Native Language Support (using gettext - GNU locale utilities)
objc Build support for the Objective C code language
objc++ Build support for the Objective C++ language
objc-gc Build support for the Objective C code language Garbage Collector
openmp Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
pch Enable precompiled header support for faster compilation at the expense of disk space and memory
pgo Build GCC using Profile Guided Optimization (PGO)
pie Build programs as Position Independent Executables (a security hardening technique)
rust Build support for the Rust language, installs gccrs.
sanitize Build support for various sanitizer functions (ASAN/TSAN/etc...)
ssp Build packages with stack smashing protector on by default
systemtap enable systemtap static probe points
test Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
vanilla Do not add extra patches which change default behaviour; DO NOT USE THIS ON A GLOBAL SCALE as the severity of the meaning changes drastically
vtv Build support for virtual table verification (a C++ hardening feature)
zstd Enable support for ZSTD compression


root #emerge --ask dev-lang/gnat-gpl


Add the location of the installed GNAT binaries to the PATH, e.g. via .bash_profile:

FILE ~/.bash_profile
export PATH="${PATH}:/usr/x86_64-pc-linux-gnu/gcc-bin/10/"

Emacs setup

As at 2024-03-13, ada-mode is effectively unmaintained, due to the primary developer having retired.[1]

The recommended way to install ada-mode is via Alire; download and install the current Linux version of Alire if necessary.

If use of Alire is not possible for some reason, ensure dev-ada/gnatcoll-core is installed:

root #emerge --ask dev-ada/gnatcoll-core

Install the latest version of ada-mode, using your preferred method of managing Emacs packages. An app-emacs/ada-mode::gnu-elpa package is available via the gnu-elpa overlay.

On the command line, change to the directory in which ada-mode has been installed, e.g.:

user $cd ~/.config/emacs/elpa/ada-mode-8.1.0/

and then run:

user $./ # This can be memory-intensive!

If the Alire alr binary is installed and configured correctly, it will be used for the build-and-install process. Otherwise, the will need to be run:

user $./

By default, files are installed into ${HOME}/.local/bin/, as the appropriate XDG directory. To specify a different location for the bin directory, pass it as the first argument to

If not using Alire, version 8.1.0 of ada-mode requires copying the file ada_annex_p_lr1_re2c_parse_table.txt from the top level of the ada-mode-8.1.0 directory to the relevant installation location.

Add the installation location to the PATH, e.g. via .bash_profile:

FILE ~/.bash_profile
export PATH="${PATH}:${HOME}/.local/bin"

and restart the login session.

Depending on the installation method, ada-mode might need to be enabled manually in the Emacs configuration file:

FILE ~/.config/emacs/init.el
(require 'ada-mode)

By default, wisi is used for things like faces (ada-face-backend) and indentation (ada-indent-backend); however, the AdaCore ada_language_server (als) can be used for cross-references, via eglot. Refer to the ada customize-group and the ada-mode home page for further information.

See also

External resources

Learning and reference



  1. Post on Retrieved on 2024-03-13.