From fe6f4b9ad7eff15e6201baea9dad737c792a328c Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Sat, 22 Nov 2014 21:00:34 -0800
Subject: [PATCH] Fix linking of sources without LTCG to a static lib with LTCG
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>
---
mkspecs/features/link_ltcg.prf | 18 ++++++++++++++++++
mkspecs/features/ltcg.prf | 18 +-----------------
mkspecs/features/qt_functions.prf | 1 +
mkspecs/features/qt_module_pris.prf | 2 ++
4 files changed, 22 insertions(+), 17 deletions(-)
create mode 100644 mkspecs/features/link_ltcg.prf
diff --git a/mkspecs/features/link_ltcg.prf b/mkspecs/features/link_ltcg.prf
new file mode 100644
index 00000000000..537021f11b0
--- /dev/null
+++ b/mkspecs/features/link_ltcg.prf
@@ -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
+ }
+}
diff --git a/mkspecs/features/ltcg.prf b/mkspecs/features/ltcg.prf
index 1459ccdc404..b0765a85c3b 100644
--- a/mkspecs/features/ltcg.prf
+++ b/mkspecs/features/ltcg.prf
@@ -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 *= $$QMAKE_LFLAGS_LTCG
diff --git a/mkspecs/features/qt_functions.prf b/mkspecs/features/qt_functions.prf
index a9a622dd1da..7961f6512a1 100644
--- a/mkspecs/features/qt_functions.prf
+++ b/mkspecs/features/qt_functions.prf
@@ -68,6 +68,7 @@ defineTest(qtAddModule) {
using_privates = true
export(using_privates)
}
+ contains(MODULE_CONFIG, ltcg): CONFIG += link_ltcg
qtProcessModuleFlags(CONFIG, QT.$${1}.CONFIG)
qtProcessModuleFlags(DEFINES, QT.$${1}.DEFINES)
diff --git a/mkspecs/features/qt_module_pris.prf b/mkspecs/features/qt_module_pris.prf
index 9a876caf5ed..03a8e5db713 100644
--- a/mkspecs/features/qt_module_pris.prf
+++ b/mkspecs/features/qt_module_pris.prf
@@ -66,6 +66,8 @@ MODULE_FWD_PRI = $$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: \
--
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