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-rw-r--r--documentation/overview-manual/overview-manual-concepts.xml47
1 files changed, 22 insertions, 25 deletions
diff --git a/documentation/overview-manual/overview-manual-concepts.xml b/documentation/overview-manual/overview-manual-concepts.xml
index 2a3d62c32a..3fc810d21a 100644
--- a/documentation/overview-manual/overview-manual-concepts.xml
+++ b/documentation/overview-manual/overview-manual-concepts.xml
@@ -1830,8 +1830,8 @@
1830 1830
1831 <para> 1831 <para>
1832 The description of tasks so far assumes that BitBake needs 1832 The description of tasks so far assumes that BitBake needs
1833 to build everything and there are no prebuilt objects 1833 to build everything and no available prebuilt objects
1834 available. 1834 exist.
1835 BitBake does support skipping tasks if prebuilt objects are 1835 BitBake does support skipping tasks if prebuilt objects are
1836 available. 1836 available.
1837 These objects are usually made available in the form of a 1837 These objects are usually made available in the form of a
@@ -1856,34 +1856,33 @@
1856 variant (e.g. generating package files in the 1856 variant (e.g. generating package files in the
1857 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package_write_deb'><filename>do_package_write_*</filename></ulink> 1857 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package_write_deb'><filename>do_package_write_*</filename></ulink>
1858 task). 1858 task).
1859 In other cases, it does not make sense, (e.g. a 1859 In other cases, it does not make sense (e.g. a
1860 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink> 1860 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
1861 task or 1861 task or a
1862 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink> 1862 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink>
1863 task) since the work involved would be equal to or greater 1863 task) since the work involved would be equal to or greater
1864 than the underlying task. 1864 than the underlying task.
1865 </para> 1865 </para>
1866 1866
1867 <para> 1867 <para>
1868 In the OpenEmbedded build system, the common tasks that 1868 In the build system, the common tasks that have setscene
1869 have setscene variants are 1869 variants are
1870 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>, 1870 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>,
1871 <filename>do_package_write_*</filename>, 1871 <filename>do_package_write_*</filename>,
1872 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-deploy'><filename>do_deploy</filename></ulink>, 1872 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-deploy'><filename>do_deploy</filename></ulink>,
1873 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-packagedata'><filename>do_packagedata</filename></ulink>, 1873 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-packagedata'><filename>do_packagedata</filename></ulink>,
1874 and 1874 and
1875 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></ulink>. 1875 <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></ulink>.
1876 Notice that these are most of the tasks whose output is an 1876 Notice that these tasks represent most of the tasks whose
1877 end result. 1877 output is an end result.
1878 </para> 1878 </para>
1879 1879
1880 <para> 1880 <para>
1881 The OpenEmbedded build system has knowledge of the 1881 The build system has knowledge of the relationship between
1882 relationship between these tasks and other tasks that 1882 these tasks and other preceding tasks.
1883 precede them.
1884 For example, if BitBake runs 1883 For example, if BitBake runs
1885 <filename>do_populate_sysroot_setscene</filename> for 1884 <filename>do_populate_sysroot_setscene</filename> for
1886 something, there is little point in running any of the 1885 something, it does not make sense to run any of the
1887 <filename>do_fetch</filename>, 1886 <filename>do_fetch</filename>,
1888 <filename>do_unpack</filename>, 1887 <filename>do_unpack</filename>,
1889 <filename>do_patch</filename>, 1888 <filename>do_patch</filename>,
@@ -1891,7 +1890,7 @@
1891 <filename>do_compile</filename>, and 1890 <filename>do_compile</filename>, and
1892 <filename>do_install</filename> tasks. 1891 <filename>do_install</filename> tasks.
1893 However, if <filename>do_package</filename> needs to be 1892 However, if <filename>do_package</filename> needs to be
1894 run, BitBake would need to run those other tasks. 1893 run, BitBake needs to run those other tasks.
1895 </para> 1894 </para>
1896 1895
1897 <para> 1896 <para>
@@ -1899,7 +1898,7 @@
1899 from an sstate cache because some objects are simply 1898 from an sstate cache because some objects are simply
1900 not required at all. 1899 not required at all.
1901 For example, you do not need a compiler or native tools, 1900 For example, you do not need a compiler or native tools,
1902 such as quilt, if there is nothing to compile or patch. 1901 such as quilt, if nothing exists to compile or patch.
1903 If the <filename>do_package_write_*</filename> packages 1902 If the <filename>do_package_write_*</filename> packages
1904 are available from sstate, BitBake does not need the 1903 are available from sstate, BitBake does not need the
1905 <filename>do_package</filename> task data. 1904 <filename>do_package</filename> task data.
@@ -1918,26 +1917,24 @@
1918 </para> 1917 </para>
1919 1918
1920 <para> 1919 <para>
1921 If objects are found in the sstate cache, the OpenEmbedded 1920 If objects are found in the sstate cache, the build system
1922 build system works backwards from the end targets specified 1921 works backwards from the end targets specified by the user.
1923 by the user. 1922 For example, if an image is being built, the build system
1924 For example, if an image is being built, the OpenEmbedded 1923 first looks for the packages needed for that image and the
1925 build system first looks for the packages needed for 1924 tools needed to construct an image.
1926 that image and the tools needed to construct an image.
1927 If those are available, the compiler is not needed. 1925 If those are available, the compiler is not needed.
1928 Thus, the compiler is not even downloaded. 1926 Thus, the compiler is not even downloaded.
1929 If something was found to be unavailable, or the 1927 If something was found to be unavailable, or the
1930 download or setscene task fails, the OpenEmbedded build 1928 download or setscene task fails, the build system then
1931 system then tries to install dependencies, such as the 1929 tries to install dependencies, such as the compiler, from
1932 compiler, from the cache. 1930 the cache.
1933 </para> 1931 </para>
1934 1932
1935 <para> 1933 <para>
1936 The availability of objects in the sstate cache is 1934 The availability of objects in the sstate cache is
1937 handled by the function specified by the 1935 handled by the function specified by the
1938 <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_HASHCHECK_FUNCTION'><filename>BB_HASHCHECK_FUNCTION</filename></ulink> 1936 <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_HASHCHECK_FUNCTION'><filename>BB_HASHCHECK_FUNCTION</filename></ulink>
1939 variable and returns a list of the objects that are 1937 variable and returns a list of available objects.
1940 available.
1941 The function specified by the 1938 The function specified by the
1942 <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_SETSCENE_DEPVALID'><filename>BB_SETSCENE_DEPVALID</filename></ulink> 1939 <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_SETSCENE_DEPVALID'><filename>BB_SETSCENE_DEPVALID</filename></ulink>
1943 variable is the function that determines whether a given 1940 variable is the function that determines whether a given