€•a2Œsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œ translations”Œ LanguagesNode”“”)”}”(hhh]”(hŒ pending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ refdomain”Œstd”Œreftype”Œdoc”Œ reftarget”Œ$/translations/zh_CN/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuŒtagname”hhh ubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/zh_TW/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/it_IT/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/ja_JP/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/ko_KR/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/pt_BR/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ$/translations/sp_SP/dev-tools/sparse”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒCopyright 2004 Linus Torvalds”h]”hŒCopyright 2004 Linus Torvalds”…””}”hh·sbah}”(h]”h ]”h"]”h$]”h&]”Œ xml:space”Œpreserve”uh1hµhhh²hh³Œ>/var/lib/git/docbuild/linux/Documentation/dev-tools/sparse.rst”h´Kubh¶)”}”(hŒ*Copyright 2004 Pavel Machek ”h]”hŒ*Copyright 2004 Pavel Machek ”…””}”hhÈsbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hµhhh²hh³hÇh´Kubh¶)”}”(hŒ0Copyright 2006 Bob Copeland ”h]”hŒ0Copyright 2006 Bob Copeland ”…””}”hhÖsbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1hµhhh²hh³hÇh´KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒSparse”h]”hŒSparse”…””}”(hhëh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1héhhæh²hh³hÇh´KubhŒ paragraph”“”)”}”(hXsSparse is a semantic checker for C programs; it can be used to find a number of potential problems with kernel code. See https://lwn.net/Articles/689907/ for an overview of sparse; this document contains some kernel-specific sparse information. More information on sparse, mainly about its internals, can be found in its official pages at https://sparse.docs.kernel.org.”h]”(hŒzSparse is a semantic checker for C programs; it can be used to find a number of potential problems with kernel code. See ”…””}”(hhûh²hh³Nh´NubhŒ reference”“”)”}”(hŒ https://lwn.net/Articles/689907/”h]”hŒ https://lwn.net/Articles/689907/”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”juh1jhhûubhŒº for an overview of sparse; this document contains some kernel-specific sparse information. More information on sparse, mainly about its internals, can be found in its official pages at ”…””}”(hhûh²hh³Nh´Nubj)”}”(hŒhttps://sparse.docs.kernel.org”h]”hŒhttps://sparse.docs.kernel.org”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”juh1jhhûubhŒ.”…””}”(hhûh²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´Khhæh²hubhå)”}”(hhh]”(hê)”}”(hŒUsing sparse for typechecking”h]”hŒUsing sparse for typechecking”…””}”(hj4h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1héhj1h²hh³hÇh´Kubhú)”}”(hŒH"__bitwise" is a type attribute, so you have to do something like this::”h]”hŒK“__bitwise†is a type attribute, so you have to do something like this:”…””}”(hjBh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´Khj1h²hubhŒ literal_block”“”)”}”(hŒ•typedef int __bitwise pm_request_t; enum pm_request { PM_SUSPEND = (__force pm_request_t) 1, PM_RESUME = (__force pm_request_t) 2 };”h]”hŒ•typedef int __bitwise pm_request_t; enum pm_request { PM_SUSPEND = (__force pm_request_t) 1, PM_RESUME = (__force pm_request_t) 2 };”…””}”hjRsbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1jPh³hÇh´Khj1h²hubhú)”}”(hX1which makes PM_SUSPEND and PM_RESUME "bitwise" integers (the "__force" is there because sparse will complain about casting to/from a bitwise type, but in this case we really _do_ want to force the conversion). And because the enum values are all the same type, now "enum pm_request" will be that type too.”h]”hX=which makes PM_SUSPEND and PM_RESUME “bitwise†integers (the “__force†is there because sparse will complain about casting to/from a bitwise type, but in this case we really _do_ want to force the conversion). And because the enum values are all the same type, now “enum pm_request†will be that type too.”…””}”(hj`h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´Khj1h²hubhú)”}”(hŒrAnd with gcc, all the "__bitwise"/"__force stuff" goes away, and it all ends up looking just like integers to gcc.”h]”hŒzAnd with gcc, all the “__bitwiseâ€/â€__force stuff†goes away, and it all ends up looking just like integers to gcc.”…””}”(hjnh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K"hj1h²hubhú)”}”(hŒwQuite frankly, you don't need the enum there. The above all really just boils down to one special "int __bitwise" type.”h]”hŒ}Quite frankly, you don’t need the enum there. The above all really just boils down to one special “int __bitwise†type.”…””}”(hj|h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K%hj1h²hubhú)”}”(hŒ"So the simpler way is to just do::”h]”hŒ!So the simpler way is to just do:”…””}”(hjŠh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K(hj1h²hubjQ)”}”(hŒtypedef int __bitwise pm_request_t; #define PM_SUSPEND ((__force pm_request_t) 1) #define PM_RESUME ((__force pm_request_t) 2)”h]”hŒtypedef int __bitwise pm_request_t; #define PM_SUSPEND ((__force pm_request_t) 1) #define PM_RESUME ((__force pm_request_t) 2)”…””}”hj˜sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1jPh³hÇh´K*hj1h²hubhú)”}”(hŒGand you now have all the infrastructure needed for strict typechecking.”h]”hŒGand you now have all the infrastructure needed for strict typechecking.”…””}”(hj¦h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K/hj1h²hubhú)”}”(hXgOne small note: the constant integer "0" is special. You can use a constant zero as a bitwise integer type without sparse ever complaining. This is because "bitwise" (as the name implies) was designed for making sure that bitwise types don't get mixed up (little-endian vs big-endian vs cpu-endian vs whatever), and there the constant "0" really _is_ special.”h]”hXuOne small note: the constant integer “0†is special. You can use a constant zero as a bitwise integer type without sparse ever complaining. This is because “bitwise†(as the name implies) was designed for making sure that bitwise types don’t get mixed up (little-endian vs big-endian vs cpu-endian vs whatever), and there the constant “0†really _is_ special.”…””}”(hj´h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K1hj1h²hubeh}”(h]”Œusing-sparse-for-typechecking”ah ]”h"]”Œusing sparse for typechecking”ah$]”h&]”uh1hähhæh²hh³hÇh´Kubhå)”}”(hhh]”(hê)”}”(hŒGetting sparse”h]”hŒGetting sparse”…””}”(hjÍh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1héhjÊh²hh³hÇh´K9ubhú)”}”(hŒqYou can get tarballs of the latest released versions from: https://www.kernel.org/pub/software/devel/sparse/dist/”h]”(hŒ;You can get tarballs of the latest released versions from: ”…””}”(hjÛh²hh³Nh´Nubj)”}”(hŒ6https://www.kernel.org/pub/software/devel/sparse/dist/”h]”hŒ6https://www.kernel.org/pub/software/devel/sparse/dist/”…””}”(hjãh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”jåuh1jhjÛubeh}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K;hjÊh²hubhú)”}”(hŒeAlternatively, you can get snapshots of the latest development version of sparse using git to clone::”h]”hŒdAlternatively, you can get snapshots of the latest development version of sparse using git to clone:”…””}”(hjøh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´K>hjÊh²hubjQ)”}”(hŒ4git://git.kernel.org/pub/scm/devel/sparse/sparse.git”h]”hŒ4git://git.kernel.org/pub/scm/devel/sparse/sparse.git”…””}”hjsbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1jPh³hÇh´KAhjÊh²hubhú)”}”(hŒOnce you have it, just do::”h]”hŒOnce you have it, just do:”…””}”(hjh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´KChjÊh²hubjQ)”}”(hŒmake make install”h]”hŒmake make install”…””}”hj"sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1jPh³hÇh´KEhjÊh²hubhú)”}”(hŒFas a regular user, and it will install sparse in your ~/bin directory.”h]”hŒFas a regular user, and it will install sparse in your ~/bin directory.”…””}”(hj0h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´KHhjÊh²hubeh}”(h]”Œgetting-sparse”ah ]”h"]”Œgetting sparse”ah$]”h&]”uh1hähhæh²hh³hÇh´K9ubhå)”}”(hhh]”(hê)”}”(hŒ Using sparse”h]”hŒ Using sparse”…””}”(hjIh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1héhjFh²hh³hÇh´KKubhú)”}”(hŒþDo a kernel make with "make C=1" to run sparse on all the C files that get recompiled, or use "make C=2" to run sparse on the files whether they need to be recompiled or not. The latter is a fast way to check the whole tree if you have already built it.”h]”hXDo a kernel make with “make C=1†to run sparse on all the C files that get recompiled, or use “make C=2†to run sparse on the files whether they need to be recompiled or not. The latter is a fast way to check the whole tree if you have already built it.”…””}”(hjWh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùh³hÇh´KMhjFh²hubhú)”}”(hŒ‚The optional make variable CF can be used to pass arguments to sparse. The build system passes -Wbitwise to sparse automatically.”h]”hŒ‚The optional make variable CF can be used to pass arguments to sparse. 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