On Sat, Jun 03, 2017 at 07:56:39PM -0400, Alain Toussaint wrote: > > First, it is really good to know of people who build svn regularly. > > My futur plans is to configure jenkins or another kind of buildbot to > do it unattended on a spare computer. > > > And glibc built without > > problems, but perhaps that is because I pass CFLAGS and CXXFLAGS of > > "-O2". > > I do use CFLAGS and CXXFLAGS for the usb that are generic enough for > x86_64. This one build is using -Os and -mtune=generic because I am > building for any x86_64 computers (at work and at home) with one usb > key targeting UEFI bioses (using the refind > http://www.rodsbooks.com/refind/ bootloader), the other one targeting > older bioses but essentially, I'm using ramdrives for the root image, > thus the -Os build. >
I think that -Os might be iffy in gcc-7.1. I'm not sure what firefox's default is, but in the past parts have been -Os and for gcc-7.1 we have to force -O2 to get all of it to work. > Other flags used are the minimum sse flags featured by the oldest > x86_64 chips ever built (amd athlon and intel pentium 4 64 bits) which > is sse and sse2. From the documentation given by gcc (source: > https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/x86-Options.html#x86-Options): > > "For the x86-32 compiler, you must use -march=cpu-type, -msse or > -msse2 switches to enable SSE extensions and make this option > effective. For the x86-64 compiler, these extensions are enabled by > default." > > "The resulting code should be considerably faster in the majority of > cases and avoid the numerical instability problems of 387 code, but > may break some existing code that expects temporaries to be 80 bits" > > Of the many years that I used gentoo (since year 2004) before and > since last year, LFS, this has never been the case and gcc always > default to the 387 for floating point instructions and data. > > To figure out the options used by default for the compiler: > > gcc -c -Q --march=native --target=help > > or in my case: gcc -c -Q --march=generic --target=help > Hmm, on this build -march= (one -) with --target-help only gives me the same output as --target-help. > the set of CFLAGS: > > "-Os -pipe -m128bit-long-double -m80387 -m64 -malign-data=cacheline > -malign-double -mtune=generic -mfancy-math-387 -mfentry > -mfp-ret-in-387 -mfpmath=sse -mglibc -mhard-float -mieee-fp -msse > -msse2 -mincoming-stack-boundary=4 -mpreferred-stack-boundary=4 > -mno-sse4 -mred-zone -msseregparm" > > Some of these are indeed redundant and I need to learn how to read and > dissect gcc source code for my desired effect (pad to 16 bytes > alignments, use sse units for math and zerofill 80 bit float to 128 > bit and finally, use all registers available). > > > I don't build systemd, but I _had_ been using gold for most of my > > builds in the last year (newer, shinier, claimed to be faster). > > I never intended to use gold either but the configure script for > systemd-233 look for it and build with it. In binutils 2.25, that > worked fine but in 2.28, there was a regression in the code and a > number of projects had build failures which was fixed in binutils svn. > I'll be attempting a build later on to document it but at the moment, > I stopped at the glibc build in chapter 6 which has more failures > compared to my usual build targeting this computer (usually, I have > only 2 tests that fail with a ton more CFLAGS but for this build, I > have 352 FAIL in the testlogs): > > A short sample (log file available on request): > > FAIL: conform/ISO/assert.h/linknamespace > FAIL: conform/ISO/locale.h/linknamespace > FAIL: conform/ISO/math.h/linknamespace > FAIL: conform/ISO/signal.h/linknamespace > FAIL: conform/ISO/stdio.h/linknamespace > FAIL: conform/ISO/stdlib.h/linknamespace > FAIL: conform/ISO/string.h/linknamespace > > I haven't installed the resulting glibc build but will rebuild again > without any CFLAGS. > > All the rest of the software build and test usually fine with my set of > CFLAGS. > > Alain For the first of those failures, https://sourceware.org/bugzilla/show_bug.cgi?id=19463 (from March last year, but apparently with a commit in March). ĸen -- I live in a city. I know sparrows from starlings. After that everything is a duck as far as I'm concerned. -- Monstrous Regiment -- http://lists.linuxfromscratch.org/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
