Date: Thu, 30 Nov 2017 17:30:35 +0100 From: Didier Kryn <kryn@...p3.fr> To: musl@...ts.openwall.com Subject: Building musl-cross-make with gnat in musl environement Le 02/11/2017 à 10:44, Didier Kryn a écrit : > I report the successfull build of the cross-compiler > x86_64-musl-gcc-6.3.0 - understanding Ada - on x86_64 Debian Wheezy. > > The toolchain for build was gcc-6.3.0 for Linux-Gnu provided by > Adacore.The build toolchain to build major version 6 must be at least > major version 5. > > Of course, the language option must be > '--enable-languages=ada,c,c++' . > > Three patches were necessary: > gnat63-terminals.diff: removes a #include <termio.h> in a C > source file. > gnat63-prj-attr.diff: corrects the layout of a record in an Ada > source file to prevent a warning concerning performance. > gnat63-xr_tabls.diff: same as the previous. In a glibc environment, x86_64-musl-gcc-6.3.0 builds without error with the three patches I have previously reported. To check there is no leak of the glibc native toolchain into the cross-compiler, I tried the build in a musl chroot (without any glibc headers or library), still with '--enable-languages=ada,c,c++'. In a first attempt, the compilation fails with the following error: ---------------------------------------- In file included from ../../src_toolchain/gcc/ada/adaint.h:290:0, from ../../src_toolchain/gcc/ada/adadecode.c:45: /usr/pkg/gcc-6.3/lib/gcc/x86_64-pc-linux-musl/6.3.0/../../../../x86_64-pc-linux-musl/include/sched.h:76:7: error: attempt to use poisoned "calloc" void *calloc(size_t, size_t); ^ /usr/pkg/gcc-6.3/lib/gcc/x86_64-pc-linux-musl/6.3.0/../../../../x86_64-pc-linux-musl/include/sched.h:116:36: error: attempt to use poisoned "calloc" #define CPU_ALLOC(n) ((cpu_set_t *)calloc(1,CPU_ALLOC_SIZE(n))) ---------------------------------------- The Ada language has "tasking" primitives, which are nowadays based on POSIX threads. For this, adaint.h and other files include <sched.h> which, unfortunately, contains a declaration of calloc() and references to it. This is unfortunate because calloc() is poisoned by gcc, to avoid interferences with its own allocation functions, and Gnat does only need a small part of sched.h. There must be a necessity, specific to musl, to make use of calloc() in sched.h, because glibc doesn't do so. A workaround, provided by the patch gnat63-adaint.diff, is to replace #include <sched.h> with the few lines of this file actually needed in adaint.h. The patch contains also #define _SCHED_H, which is necessary to prevent the inclusion of sched.h by other files, directly or indirectly. With this additional patch, x86_64-musl-gcc-6.3.0 builds without error both in a glibc environement and in a musl environment. Didier View attachment "gnat63-adaint.diff" of type "text/x-patch" (1237 bytes)
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