Merge pull request #12097 from ConnorBaker/feat/meson-O3-LTO

packaging: use release builds and LTO by default

Author: Ericson2314

nix-meson-build-support/common/meson.build

@@ -16,7 +16,3 @@ add_project_arguments(
   '-Wno-deprecated-declarations',
   language : 'cpp',
 )
-
-if get_option('buildtype') not in ['debug']
-  add_project_arguments('-O3', language : 'cpp')
-endif

packaging/dependencies.nix

@@ -66,6 +66,21 @@ let
 
   mesonLayer = finalAttrs: prevAttrs:
     {
+      # NOTE:
+      # As of https://github.com/NixOS/nixpkgs/blob/8baf8241cea0c7b30e0b8ae73474cb3de83c1a30/pkgs/by-name/me/meson/setup-hook.sh#L26,
+      # `mesonBuildType` defaults to `plain` if not specified. We want our Nix-built binaries to be optimized by default.
+      # More on build types here: https://mesonbuild.com/Builtin-options.html#details-for-buildtype.
+      mesonBuildType = "release";
+      # NOTE:
+      # Users who are debugging Nix builds are expected to set the environment variable `mesonBuildType`, per the
+      # guidance in https://github.com/NixOS/nix/blob/8a3fc27f1b63a08ac983ee46435a56cf49ebaf4a/doc/manual/source/development/debugging.md?plain=1#L10.
+      # For this reason, we don't want to refer to `finalAttrs.mesonBuildType` here, but rather use the environment variable.
+      preConfigure = prevAttrs.preConfigure or "" + ''
+        case "$mesonBuildType" in
+        release|minsize) appendToVar mesonFlags "-Db_lto=true"  ;;
+        *)               appendToVar mesonFlags "-Db_lto=false" ;;
+        esac
+      '';
       nativeBuildInputs = [
         pkgs.buildPackages.meson
         pkgs.buildPackages.ninja

src/libcmd/meson.build

@@ -4,8 +4,6 @@ project('nix-cmd', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libexpr-c/meson.build

@@ -4,8 +4,6 @@ project('nix-expr-c', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libexpr-test-support/meson.build

@@ -4,8 +4,6 @@ project('nix-expr-test-support', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libexpr-tests/meson.build

@@ -4,8 +4,6 @@ project('nix-expr-tests', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libexpr/meson.build

@@ -4,8 +4,6 @@ project('nix-expr', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libfetchers-tests/meson.build

@@ -4,8 +4,6 @@ project('nix-fetchers-tests', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libfetchers/meson.build

@@ -4,8 +4,6 @@ project('nix-fetchers', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',

src/libflake-c/meson.build

@@ -4,8 +4,6 @@ project('nix-flake-c', 'cpp',
     'cpp_std=c++2a',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
-    'debug=true',
-    'optimization=2',
     'errorlogs=true', # Please print logs for tests that fail
   ],
   meson_version : '>= 1.1',