mesonbuild/meson

Libraries built with lto and meson/ninja are larger than with configure/make

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#3,059 opened on Feb 13, 2018

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Description

Using meson-0.43.0, ninja-1.8.2, gcc-7.2.0

Building glib-2.54.3 with lto as per below results in the following library sizes for libgio-2.0.so.0.5400.3 (stripped)

1,419,000 bytes with configure/make 1,525,688 bytes with meson/ninja

i.e. about 100kb or 10% larger with meson/ninja

from "ninja -v", it appears that lto is being used at link time, but maybe this isn't the case?

CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe -fno-exceptions -fno-rtti" meson --prefix=/usr/local --buildtype=plain -Dwith-pcre=system -Dwith-docs=no -Denable-libmount=no ..

ninja [fails at link ninja: build stopped: subcommand failed unless locale set to UTF8] [1m 17.80s]
sudo ninja install

CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe -fno-exceptions -fno-rtti" ./configure --prefix=/usr/local --localstatedir=/var --disable-static --with-pcre=system --disable-libmount

find . -name Makefile -type f -exec sed -i 's/-g -O2//g' {} \;

make [1m 31.96s]
sudo make install

Contributor guide

Tech stack
ccpppython
Domain
build systemperformance
Issue type
performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C/C++ compilation basicsLink time optimization (LTO)Meson build systemNinja build tool
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate how Meson passes linker flags for LTO compared to configure/make. Look at the ninja backend code in mesonbuild/backend/ninjabackend.py to see if extra flags are added. Analyze the difference in resulting object files and link commands. Consider testing with different optimization levels and verifying that flto and fuse linker plugin are correctly passed. The goal is to identify the cause of the larger binary and propose a patch to minimize size.