From 5275fc784c8113c84c85ca028ce621f68fe6642b Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Tue, 19 Dec 2023 16:00:11 +0000 Subject: [PATCH] Do not build sparc32 libgcc functions into static libc Since GCC commit f31a019d1161ec78846473da743aedf49cca8c27 "Emit funcall external declarations only if actually used.", the glibc testsuite has failed to build for 32-bit SPARC with GCC mainline. /scratch/jmyers/glibc-bot/install/compilers/sparc64-linux-gnu/lib/gcc/sparc64-glibc-linux-gnu/14.0.0/../../../../sparc64-glibc-linux-gnu/bin/ld: /scratch/jmyers/glibc-bot/install/compilers/sparc64-linux-gnu/lib/gcc/sparc64-glibc-linux-gnu/14.0.0/32/libgcc.a(_divsi3.o): in function `.div': /scratch/jmyers/glibc-bot/src/gcc/libgcc/config/sparc/lb1spc.S:138: multiple definition of `.div'; /scratch/jmyers/glibc-bot/build/glibcs/sparcv9-linux-gnu/glibc/libc.a(sdiv.o):/scratch/jmyers/glibc-bot/src/glibc/gnulib/../sysdeps/sparc/sparc32/sparcv9/sdiv.S:13: first defined here /scratch/jmyers/glibc-bot/install/compilers/sparc64-linux-gnu/lib/gcc/sparc64-glibc-linux-gnu/14.0.0/../../../../sparc64-glibc-linux-gnu/bin/ld: disabling relaxation; it will not work with multiple definitions collect2: error: ld returned 1 exit status make[3]: *** [../Rules:298: /scratch/jmyers/glibc-bot/build/glibcs/sparcv9-linux-gnu/glibc/nptl/tst-cancel24-static] Error 1 https://sourceware.org/pipermail/libc-testresults/2023q4/012154.html I'm not sure of the exact sequence of undefined references that cause first the glibc object file defining .div and then the libgcc object file defining both .div and .udiv to be pulled in (which must have been perturbed by that GCC change in a way that introduced the build failure), but I think the failure illustrates that it's inherently fragile for glibc to define symbols in separate object files that libgcc defines in the same object file - and indeed for glibc to redefine libgcc symbols at all, since the division into object files shouldn't really be part of the interface between libgcc and libc. These symbols appear to be in libc only for compatibility, maybe one of the cases where they were accidentally exported from shared libc in glibc 2.0 before the introduction of symbol versioning and so programs started expecting shared libc to provide them. Thus, there is no need to have them in static libc. Add this set of libgcc functions to shared-only-routines so they are no longer provided in static libc. (No change is made regarding .mul - dotmul source file - since unlike the other symbols in this grouping, it doesn't actually appear to be a libgcc symbol, at least in current GCC.) Tested with build-many-glibcs.py for sparcv9-linux-gnu with GCC mainline. --- sysdeps/sparc/sparc32/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/sysdeps/sparc/sparc32/Makefile b/sysdeps/sparc/sparc32/Makefile index b792e56710..cc1db68cc6 100644 --- a/sysdeps/sparc/sparc32/Makefile +++ b/sysdeps/sparc/sparc32/Makefile @@ -17,6 +17,7 @@ ifeq ($(subdir),gnulib) sysdep_routines = dotmul umul $(divrem) alloca +shared-only-routines += umul $(divrem) endif # gnulib divrem := sdiv udiv rem urem