qt5base-lts/mkspecs/features/qt_module_headers.prf
Thiago Macieira cb09e1e889 Automatically enable precompiled headers for Qt modules
We'll use the master depends header for the module as the precompilation
header. We could use the master include, but tests show that
precompilation benefits taper off for big precompiled headers. The
important part is to get the Standard Library headers precompiled.

Each module can still override which header to precompile by setting
PRECOMPILED_HEADER after load(qt_modules). It can also turn off
precompiled headers by setting that to empty or by CONFIG -=
precompile_header.

Testing a few build times shows the following improvements (GCC 4.8 with
-O3 and C++11):
  QtPrintSupport: 14.7%
  QtOpenGL:       22.7%
  QtDBus:         29.5%
  QtSvg:          -2.4%
  QtXmlPatterns:  26.1%
  QtQml:          21.6%
  QtQuick:        25.0%
  QtMultimedia:    9.0%
  QtSerialPort:  -30.0%
  QtHelp:          5.6%

The numbers also show that precompilation is worse for small modules.

Change-Id: I3793fafcedaff5456527cd6b3777ffd162975c36
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
2014-05-27 06:26:57 +02:00

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#
# W A R N I N G
# -------------
#
# This file is not part of the Qt API. It exists purely as an
# implementation detail. It may change from version to version
# without notice, or even be removed.
#
# We mean it.
#
load(qt_build_paths)
!build_pass:git_build {
qtPrepareTool(QMAKE_SYNCQT, syncqt)
minimal_syncqt {
QMAKE_SYNCQT += -minimal $$QMAKE_SYNCQT_OPTIONS
} else {
contains(QT_CONFIG, private_tests): \ # -developer-build
QMAKE_SYNCQT += -check-includes
QMAKE_SYNCQT += -module $$MODULE_INCNAME -version $$VERSION
}
QMAKE_SYNCQT += \
-outdir $$MODULE_BASE_OUTDIR $$MODULE_SYNCQT_DIR
!silent: message($$QMAKE_SYNCQT)
system($$QMAKE_SYNCQT)|error("Failed to run: $$QMAKE_SYNCQT")
}
minimal_syncqt: return()
#load up the headers info
git_build: \
INC_PATH = $$MODULE_BASE_OUTDIR
else: \
INC_PATH = $$MODULE_BASE_INDIR
include($$INC_PATH/include/$$MODULE_INCNAME/headers.pri, "", true)
for (injection, SYNCQT.INJECTIONS) {
injects = $$split(injection, :)
fwd_hdr = $$member(injects, 1)
MAIN_FWD = $$INC_PATH/include/$$MODULE_INCNAME/$$fwd_hdr
MAIN_FWD_CONT = '$${LITERAL_HASH}include "$$member(injects, 0)"'
write_file($$MAIN_FWD, MAIN_FWD_CONT)|error("Aborting.")
injects = $$member(injects, 2, -1)
for (inject, injects) {
CLASS_FWD = $$INC_PATH/include/$$MODULE_INCNAME/$$inject
CLASS_FWD_CONT = '$${LITERAL_HASH}include "$$fwd_hdr"'
write_file($$CLASS_FWD, CLASS_FWD_CONT)|error("Aborting.")
}
}
autogen_warning = \
"/* This file was generated by qmake with the info from <root>/$$relative_path($$_PRO_FILE_, $$MODULE_BASE_INDIR). */"
# Create a module master depends header
MODULE_MASTER_DEPS_HEADER = $$MODULE_BASE_OUTDIR/include/$$MODULE_INCNAME/$${MODULE_INCNAME}Depends
!build_pass {
MODULE_MASTER_DEPS_HEADER_CONT = $$autogen_warning
for(dep, MODULE_DEPENDS) {
depname = $$eval(QT.$${dep}.name)
MODULE_MASTER_DEPS_HEADER_CONT += "$${LITERAL_HASH}include <$$depname/$$depname>"
}
write_file($$MODULE_MASTER_DEPS_HEADER, MODULE_MASTER_DEPS_HEADER_CONT)|error("Aborting.")
}
SYNCQT.HEADER_FILES += $$MODULE_MASTER_DEPS_HEADER
isEmpty(PRECOMPILED_HEADER): PRECOMPILED_HEADER = $$MODULE_MASTER_DEPS_HEADER
CONFIG += qt_install_headers