73 lines
2.3 KiB
Plaintext
73 lines
2.3 KiB
Plaintext
$NetBSD: README,v 1.8 2012/03/29 18:35:11 wiz Exp $
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Building multi-ABI libraries for NetBSD platforms.
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src/compat has a framework to (re)build the libraries shipped with
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NetBSD for a different ABI than the default for that platform. This
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allows 32-bit libraries for the amd64 and sparc64 ports, and enables
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the mips64 port to support all three of old-style 32-bit ("o32"), the
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new 32-bit (default, "n32", 64-bit CPU required) or the 64-bit ABI.
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The basic premise is to re-set $MAKEOBJDIR to fresh subdirectory
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underneath src/compat and rebuild the libraries with a different set
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of options. Each platform wanting support should create their port
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subdirectory directly in src/compat, and then one subdirectory in here
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for each ABI required, e.g., src/compat/amd64/i386 is where we build
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the 32-bit compat libraries for the amd64 port. In each of these
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subdirectories, a small Makefile and makefile fragment should exist. The
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Makefile should set BSD_MK_COMPAT_FILE to equal the fragment, and then
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include "../../compatsubdir.mk". E.g., amd64/i386/Makefile has:
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BSD_MK_COMPAT_FILE=${.CURDIR}/bsd.i386.mk
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.include "../../compatsubdir.mk"
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In the makefile fragment any changes to ABI flags are passed here
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and the MLIBDIR variable must be set to the subdirectory in /usr/lib
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where libraries for the ABI will be installed. There are a couple of
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helper Makefiles around. amd64/i386/bsd.i386.mk looks like:
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LD+= -m elf_i386
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MLIBDIR= i386
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LIBC_MACHINE_ARCH= ${MLIBDIR}
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COMMON_MACHINE_ARCH= ${MLIBDIR}
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KVM_MACHINE_ARCH= ${MLIBDIR}
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PTHREAD_MACHINE_ARCH= ${MLIBDIR}
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BFD_MACHINE_ARCH= ${MLIBDIR}
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CSU_MACHINE_ARCH= ${MLIBDIR}
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CRYPTO_MACHINE_CPU= ${MLIBDIR}
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LDELFSO_MACHINE_CPU= ${MLIBDIR}
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.include "${NETBSDSRCDIR}/compat/m32.mk"
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and the referenced m32.mk looks like:
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COPTS+= -m32
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CPUFLAGS+= -m32
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LDADD+= -m32
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LDFLAGS+= -m32
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MKDEPFLAGS+= -m32
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.include "Makefile.compat"
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compatsubdir.mk holds the list of subdirectories (the libraries and
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ld.elf_so) to build with this ABI.
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archdirs.mk holds the list of subdirectories for each port.
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Makefile.compat has the basic framework to force the right paths for
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library and ld.elf_so linkage. It contains a hack to create subdirectories
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in the build that should be fixed.
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dirshack/Makefile is a hack to get objdirs created timely, and should
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be fixed in a better way.
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mrg@eterna.com.au
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december 2009
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