AuroraMiddleware/qt5base-lts
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Fix linking of sources without LTCG to a static lib with LTCG

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Whenever a binary is created and linked against a static lib that was
compiled with LTCG, the final linking step requires the compiler flags
so that the pre-compiled data in the shared library can get properly
compiled.

This could happen for a static build of Qt with LTCG, but also happens
frequently for Qt's own build when linking regular libraries and
applications against QtBootstrap or QtPlatformSupport. The linking fails
when the target is a shared library (example: QtWaylandClient linking
against QtPlatformSupport).

The .prl file actually contains the "ltcg" flag, so the best solution
would actually be to process that flag there and add link_ltcg if any
dependent .prl has "ltcg", but I couldn't find out how to do that.

Change-Id: I4a75a14d1dcb8c2089a427285e25d5555df7d7d3
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
This commit is contained in:
Thiago Macieira 2014-11-22 21:00:34 -08:00
parent 2b258dc80b
commit fe6f4b9ad7
4 changed files with 22 additions and 17 deletions
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18
mkspecs/features/link_ltcg.prf Normal file
View File

@ -0,0 +1,18 @@
gcc {
# When doing link-time code generation, we need to pass the compiler
# flags during linking the stage too. This file is processed after
# default_post.prf, so the QMAKE_CXXFLAGS already contains
# QMAKE_CXXFLAGS_DEBUG or _RELEASE.
use_c_linker {
# use_c_linker.prf is in effect, use the C flags
QMAKE_LFLAGS_LTCG += $$QMAKE_CFLAGS $$QMAKE_CFLAGS_LTCG
QMAKE_LFLAGS_APP += $$QMAKE_CFLAGS_APP
QMAKE_LFLAGS_SHLIB += $$QMAKE_CFLAGS_SHLIB
QMAKE_LFLAGS_PLUGIN += $$QMAKE_CFLAGS_SHLIB
} else {
QMAKE_LFLAGS_LTCG = $$QMAKE_CXXFLAGS $$QMAKE_LFLAGS_LTCG
QMAKE_LFLAGS_APP += $$QMAKE_CXXFLAGS_APP
QMAKE_LFLAGS_SHLIB += $$QMAKE_CXXFLAGS_SHLIB
QMAKE_LFLAGS_PLUGIN += $$QMAKE_CFLAGS_SHLIB
}
}

18
mkspecs/features/ltcg.prf
View File

@ -31,25 +31,9 @@ CONFIG(release, debug|release) {
QMAKE_CXXFLAGS_LTCG =
QMAKE_LFLAGS_LTCG =
}
# When doing link-time code generation, we need to pass the compiler
# flags during linking stage too. This file is processed after
# default_post.prf, so the QMAKE_CXXFLAGS already contains
# QMAKE_CXXFLAGS_DEBUG or _RELEASE.
use_c_linker {
# use_c_linker.prf is in effect, use the C flags
QMAKE_LFLAGS_LTCG += $$QMAKE_CFLAGS $$QMAKE_CFLAGS_LTCG
QMAKE_LFLAGS_APP += $$QMAKE_CFLAGS_APP
QMAKE_LFLAGS_SHLIB += $$QMAKE_CFLAGS_SHLIB
QMAKE_LFLAGS_PLUGIN += $$QMAKE_CFLAGS_SHLIB
} else {
QMAKE_LFLAGS_LTCG = $$QMAKE_CXXFLAGS $$QMAKE_LFLAGS_LTCG
QMAKE_LFLAGS_APP += $$QMAKE_CXXFLAGS_APP
QMAKE_LFLAGS_SHLIB += $$QMAKE_CXXFLAGS_SHLIB
QMAKE_LFLAGS_PLUGIN += $$QMAKE_CFLAGS_SHLIB
}
}
load(link_ltcg)
QMAKE_CFLAGS *= $$QMAKE_CFLAGS_LTCG
QMAKE_CXXFLAGS *= $$QMAKE_CXXFLAGS_LTCG
QMAKE_LFLAGS *= $$QMAKE_LFLAGS_LTCG

1
mkspecs/features/qt_functions.prf
View File

@ -68,6 +68,7 @@ defineTest(qtAddModule) {
using_privates = true
export(using_privates)
}
contains(MODULE_CONFIG, ltcg): CONFIG += link_ltcg
qtProcessModuleFlags(CONFIG, QT.$${1}.CONFIG)
qtProcessModuleFlags(DEFINES, QT.$${1}.DEFINES)

2
mkspecs/features/qt_module_pris.prf
View File

@ -66,6 +66,8 @@ MODULE_FWD_PRI = $$mod_work_pfx/qt_lib_$${MODULE_ID}.pri
module_build_type =
internal_module: \
module_build_type += internal_module
ltcg: \
module_build_type += ltcg
!isEmpty(MODULE_CONFIG): \
module_config = "QT.$${MODULE_ID}.CONFIG = $$MODULE_CONFIG"
else: \