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SCons: fix the remaining shared linking problems on Ubuntu-Precise

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Our libraries constitute a clear dependency hierarchy,
we do not want circular dependencies. Declaring these
dependencies while creating the shared libraries would
allow strict checking by the linker; but unfortunately
this also creates transitive depdendencies stored as
DT_NEEDED tags.

While basically this would be just fine, the resolution of $ORIGIN
on gets confused in case of transitively defined library dependencies
over multiple hops, especially in case when actually no symbol of this
transitive dependency is used. Since these newer systems set the
--as-needed switch for linking by default, these unnecessary
DT_NEEDED entries will be purged from the executable, but of course
not from the shared library causing the transitive dependencies.
As a consequence, when loading the executable, the $ORIGIN resolution
mechanism doesn't act on the dependencies recorded in the library,
causing the shared loader to abort with an "unresolved dependency"

So the resolution for these problems is not to use transitive
dependencies on libraries intended to be found via $ORIGIN
This commit is contained in:
Fischlurch 2013-01-04 22:44:27 +01:00
parent 56d42e9b04
commit 0710d51aaf
1 changed files with 5 additions and 5 deletions
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10
src/SConscript
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@ -11,12 +11,12 @@ Import('env icons config')
# define the source file/dirs comprising each artifact to be built.
lLib = env.SharedLibrary('lumiera', srcSubtree('lib'), install=True)
lApp = env.SharedLibrary('lumieracommon', srcSubtree('common'), install=True, LIBS=lLib)
lBack = env.SharedLibrary('lumierabackend', srcSubtree('backend'),install=True)
lProc = env.SharedLibrary('lumieraproc', srcSubtree('proc'), install=True)
lLib = env.SharedLibrary('lumiera', srcSubtree('lib'), install=True)
lApp = env.SharedLibrary('lumieracommon', srcSubtree('common'), install=True)
lBack = env.SharedLibrary('lumierabackend', srcSubtree('backend'), install=True)
lProc = env.SharedLibrary('lumieraproc', srcSubtree('proc'), install=True)
core = lLib+lApp+lBack+lProc
core = lProc+lBack+lApp+lLib # in reverse dependency order
core_lib = core
support_lib = lLib