Re: libgo patch committed: Change build procedure to use build tags

[Ian Lance Taylor <iant@golang.org>]

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On Thu, Aug 11, 2016 at 8:15 AM, Rainer Orth
<ro@cebitec.uni-bielefeld.de> wrote:
>
>> Go packages use build tags (see the section on Build Constraints at
>> https://golang.org/pkg/go/build/) to select which files to build on
>> specific systems.
>>
>> Previously the libgo Makefile explicitly listed the set of files to
>> compile for each package.  For packages that use build tags, this
>> required a lot of awkward automake conditionals in the Makefile.
>>
>> This patch changes the build to look at the build tags in the files.
>> The new shell script libgo/match.sh does the matching.  This required
>> adjusting a lot of build tags, and removing some files that are never
>> used.  I verified that the exact same sets of files are compiled on
>> x86_64-pc-linux-gnu.  I also tested the build on i386-sun-solaris
>> (building for both 32-bit and 64-bit).
>>
>> Writing match.sh revealed some bugs in the build tag handling that
>> already exists, in a slightly different form, in the gotest shell
>> script.  This patch fixes those problems as well.
>>
>> The old code used automake conditionals to handle systems that were
>> missing strerror_r and wait4.  Rather than deal with those in Go,
>> those functions are now implemented in runtime/go-nosys.c when
>> necessary, so the Go code can simply assume that they exist.
>>
>> The os testsuite looked for dir_unix.go, which was never built for
>> gccgo and has now been removed.  I changed the testsuite to look for
>> dir.go instead.
>>
>> Note that if you have an existing build directory, you will have to
>> remove all the .dep files in TARGET/libgo after updating to this
>> patch.  There isn't anything that will force them to update
>> automatically.
>>
>> Bootstrapped on x86_64-pc-linux-gnu and i386-sun-solaris.  Ran Go
>> testsuite on x86_64-pc-linux-gnu.  Committed to mainline.
>
> this patch broke i386-pc-solaris2.12 and sparc-sun-solaris2.12
> bootstrap, however: in both cases, the 64-bit build of os.lo fails like this:
>
> /vol/gcc/src/hg/trunk/local/libgo/go/os/dir.go:82:8: error: reference to undefined name 'libc_readdir_r'
>    i := libc_readdir_r(file.dirinfo.dir, entryDirent, pr)
>         ^
>
> Neither dir_largefile.go (which is correctly omitted, being 32-bit only)
> nor dir_regfile.go (which is needed here) is included in the
> compilation.

Sorry, I don't know what I messed up in my testing.  I committed the
appended patch, which should fix the problem.

Ian

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Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 239332)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@
-5e05b7bc947231b4d5a8327bf63e2fa648e51dc7
+fe1e77f843220503f1f8d5ea7dd5e307580e1d38
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: libgo/go/os/dir_regfile.go
===================================================================
--- libgo/go/os/dir_regfile.go	(revision 239189)
+++ libgo/go/os/dir_regfile.go	(working copy)
@@ -6,8 +6,8 @@
 // license that can be found in the LICENSE file.
 
 // +build !linux
-// +build !solaris,386
-// +build !solaris,sparc
+// +build !solaris !386
+// +build !solaris !sparc
 
 package os