arch: use gperf to generate a perfact hash to lookup syscall names

This patch significantly improves the performance of
seccomp_syscall_resolve_name since it replaces the expensive strcmp
for each syscall in the database, with a lookup table.

The complexity for syscall_resolve_num is not changed and it
uses the linear search, that is anyway less expensive than
seccomp_syscall_resolve_name as it uses an index for comparison
instead of doing a string comparison.

On my machine, calling 1000 seccomp_syscall_resolve_name_arch and
seccomp_syscall_resolve_num_arch over the entire syscalls DB passed
from ~0.45 sec to ~0.06s.

PM: After talking with Giuseppe I made a number of additional
changes, some substantial, the highlights include:
* various style tweaks
* .gitignore fixes
* fixed subject line, tweaked the description
* dropped the arch-syscall-validate changes as they were masking
  other problems
* extracted the syscalls.csv and file deletions to other patches
  to keep this one more focused
* fixed the x86, x32, arm, all the MIPS ABIs, s390, and s390x ABIs as
  the syscall offsets were not properly incorporated into this change
* cleaned up the ABI specific headers
* cleaned up generate_syscalls_perf.sh and renamed to
  arch-gperf-generate
* fixed problems with automake's file packaging

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Tom Hromatka <tom.hromatka@oracle.com>
[PM: see notes in the "PM" section above]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/.travis.yml b/.travis.yml
index 7f54f00..a509652 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,6 +39,7 @@ addons:
       - valgrind
       - clang
       - lcov
+      - gperf
 
 env:
   global: