Page History

...

Build a Lustre patched kernel with ggov enabled. This document assumes a Lustre patched kernel version: 2.6.32-279.19.1.el6_lustre_gcov.x86_64.
1. To enable gcov set CONFIG_GCOV_KERNEL=y. It is not necessary to set CONFIG_GCOV_PROFILE_ALL. With the first option set, profiling can be enable on a per-module basis during the Lustre build.
2. Build the kernel as usual (i.e. using GCC). Trying to build it with Clang is unlikely to succeed.
Build SPL and ZFS if necessary.
Build Lustre software using a script included in lustre-static-analysis for assistance:
Code Block
language none
# cd lustre-release # git clean -fxd # sh autogen.sh && ./configure # ~/lustre-static-analysis/DeclUse/decl_use_make GCOV_PROFILE=y
For each .c to .o compilation performed by GCC, decl_use_make will also run Clang with the lustre-static-analysis plugin. When compiling file.c the output file.o is produced by GCC and should be identical to a normal Lustre build. Simultaneously decl_use_make instructs Clang to read file.c and produce corresponding file.o._Ref and file.o._Err. Note: Clang does not compile file.c to an object file. Clang parses file.c and produces an AST in memory. The file.o._Err file records the errors Clang discovered during processing file.c.
Info
In practice, file.o is first build as .tmp_file.o then renamed to file.o. This happens in the Makefile so GCC and Clang are unaware of the file.o.

...

Useful products from Clang static analysis

For the purposes of static analysis provided by the Clang plugin, the file.o._Ref are intermediate file is and not of primary general interest. For example:

Code Block

# find lustre/llite -name '*._Ref'
./lustre/llite/.tmp_rw.o._Ref
./lustre/llite/.tmp_dir.o._Ref
./lustre/llite/.tmp_vvp_lock.o._Ref
./lustre/llite/.tmp_remote_perm.o._Ref
...
#
# ls -lh ./lustre/llite/.tmp_file.o._Ref
-rw-r--r-- 1 root root 7.9M May 16 10:47 ./lustre/llite/.tmp_file.o._Ref
# grep ll_file_read ./lustre/llite/.tmp_file.o._Ref
Decl  Function  lustre/llite/file.c:1062:16:ll_file_read  lustre/llite/file.c:1062:16
Def   Function  lustre/llite/file.c:1062:16:ll_file_read  lustre/llite/file.c:1062:16
Use   Function  lustre/llite/file.c:1062:16:ll_file_read  lustre/llite/file.c:3026:27
Use   Function  lustre/llite/file.c:1062:16:ll_file_read  lustre/llite/file.c:3046:27
Use   Function  lustre/llite/file.c:1062:16:ll_file_read  lustre/llite/file.c:3069:27
#
# grep lu_fid ./lustre/llite/.tmp_file.o._Ref
Decl  Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:118:8
Def   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:118:8
Decl  Field     lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq  lustre/include/lustre/lustre_user.h:125:8
Decl  Field     lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_oid  lustre/include/lustre/lustre_user.h:127:8
Decl  Field     lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_ver  lustre/include/lustre/lustre_user.h:133:8
Use   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:137:16
Use   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:142:16
Use   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:170:17
Use   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:189:17
Use   Record    lustre/include/lustre/lustre_user.h:118:8:lu_fid        lustre/include/lustre/lustre_user.h:379:16
#
# grep lu_fid:f_seq ./lustre/llite/.tmp_file.o._Ref
Decl  Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_user.h:125:8
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:395:21
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:548:7
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:650:14
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:747:8
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:771:6
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:772:3
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:820:7
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:835:7
Use   Field  lustre/include/lustre/lustre_user.h:118:8:lu_fid:f_seq     lustre/include/lustre/lustre_idl.h:846:7
#

In each ._Ref files, the columns from left to right are:

Column 1

Column 2

Column 3

Column 4

The type of operation declared on the symbol. Either:

Decl = declared

Def = defined

Method

Use = used

The type of the symbol. Either:

Record

Field

Function

Canonical declaration of the symbol referenced

Location of the reference

Automatic processing of analysis output

Executing the script useage-post.sh will create a directory called Unused-2.4.50 (or more generally: Unused-$(git describe))

...

THe files of interest include:

Err

GetOnly

MacroUnused

SetOnly

Undefined

Automatic processing of analysis output

Executing the script useage-post.sh will create a directory called Unused-2.4.50 (or more generally: Unused-$(git describe))

The file Ref is the sorted and uniqed concatenation of the ._Ref files produced by usage-make.sh. The remaining files are produced by filtering and comparing various parts of Ref. For example, there are the unused declarations in lustre/llite:

Code Block

# grep /llite/ UnusedDeclUse-2.4.50/Unused
EnumConstant  lustre/llite/llite_internal.h:121:9:LLIF_CONTENDED
EnumConstant  lustre/llite/llite_internal.h:123:9:LLIF_SRVLOCK
EnumConstant  lustre/llite/llite_internal.h:379:9:STATS_TRACK_LAST
Field         lustre/llite/llite_internal.h:1020:8:vvp_thread_info:vti_lvb
Field         lustre/llite/llite_internal.h:1020:8:vvp_thread_info:vti_queue
Field         lustre/llite/llite_internal.h:1078:8:ll_lock_tree:lt_fd
Field         lustre/llite/llite_internal.h:1078:8:ll_lock_tree:lt_locked_list
Field         lustre/llite/llite_internal.h:1078:8:ll_lock_tree:lt_root
Field         lustre/llite/llite_internal.h:1611:8:if_quotactl_18:obd_type
Field         lustre/llite/llite_internal.h:638:8:it_cb_data:hash
Field         lustre/llite/llite_internal.h:71:8:ll_dentry_data:lld_cwd_och
Field         lustre/llite/llite_internal.h:71:8:ll_dentry_data:lld_mnt_och
Field         lustre/llite/llite_internal.h:920:8:vvp_io:cui_partpage
Function      lustre/llite/llite_internal.h:1086:28:ll_node_from_inode
Function      lustre/llite/llite_internal.h:1154:19:ll_mds_max_easize
Function      lustre/llite/llite_internal.h:1216:5:ll_is_file_contended
Function      lustre/llite/llite_internal.h:663:20:ll_ra_read_get
Function      lustre/llite/llite_internal.h:713:6:ll_removepage
Function      lustre/llite/llite_internal.h:716:5:ll_file_punch
Function      lustre/llite/llite_internal.h:717:9:ll_file_lockless_io
Function      lustre/llite/llite_internal.h:718:6:ll_clear_file_contended
Function      lustre/llite/llite_internal.h:719:5:ll_sync_page_range
Function      lustre/llite/llite_internal.h:830:7:ll_read_opt
Function      lustre/llite/llite_internal.h:836:15:ll_inode_from_lock
Function      lustre/llite/llite_internal.h:864:6:lustre_dump_inode
Function      lustre/llite/llite_lib.c:1085:6:lu_context_keys_dump
Function      lustre/llite/llite_mmap.c:577:29:file_to_user
Function      lustre/llite/llite_mmap.c:58:14:ll_nopage
Function      lustre/llite/lloop.c:901:1:__inittest
Function      lustre/llite/lloop.c:902:1:__exittest
Function      lustre/llite/lloop.c:904:1:__check_max_loop
Function      lustre/llite/namei.c:78:5:ll_unlock
Function      lustre/llite/super25.c:232:1:__inittest
Function      lustre/llite/super25.c:233:1:__exittest
Function      lustre/llite/vvp_dev.c:172:5:vvp_global_init
Function      lustre/llite/vvp_dev.c:185:6:vvp_global_fini
Record        lustre/llite/llite_internal.h:1078:8:ll_lock_tree
Typedef       lustre/llite/llite_internal.h:1075:25:rb_node_t
Var           lustre/llite/llite_internal.h:658:25:ll_async_page_slab
Var           lustre/llite/llite_internal.h:659:15:ll_async_page_slab_size
Var           lustre/llite/llite_internal.h:84:31:ll_pgcache_seq_fops
Var           lustre/llite/llite_internal.h:884:31:ll_special_chr_inode_fops
Var           lustre/llite/llite_internal.h:885:31:ll_special_chr_file_fops
Var           lustre/llite/llite_internal.h:886:31:ll_special_blk_inode_fops
Var           lustre/llite/llite_internal.h:887:31:ll_special_fifo_inode_fops
Var           lustre/llite/llite_internal.h:888:31:ll_special_fifo_file_fops
Var           lustre/llite/llite_internal.h:889:31:ll_special_sock_inode_fops
Var           lustre/llite/rw26.c:559:33:ll_aops
Var           lustre/llite/vvp_dev.c:544:24:vvp_dump_pgcache_file_ops

...

Page tree

Versions Compared

Old Version 7

New Version 8

Key

Useful products from Clang static analysis

Automatic processing of analysis output

Automatic processing of analysis output