llvm-project/clang-tools-extra
Alexander Kornienko 6180337fe1 [clang-tidy] Optimize GlobList::contains
With large lists of checks and large number of warnings GlobList::contains
starts being ridiculously CPU hungry, since it runs regexp match per glob.
Caching results of glob matching in a StringMap significantly speeds up check
filtering even for small GlobLists.

/tmp/q.cc:

void f() {
  int I;
  {int I;}
  {int I;}
  {int I;}
  ... // 200k times
}

Before the patch:

GlobList with 2 entries:
  $ time clang-tidy-old -checks=-*,modernize-use-override /tmp/q.cc -- -Wshadow
  200000 warnings generated.
  Suppressed 200000 warnings (200000 with check filters).

  real    0m3.826s
  user    0m3.176s
  sys     0m0.504s

GlobList with 28 entries:
  $ time clang-tidy-old -checks=-*,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,modernize-use-override /tmp/q.cc -- -Wshadow
  200000 warnings generated.
  Suppressed 200000 warnings (200000 with check filters).

  real    0m5.000s
  user    0m4.744s
  sys     0m0.060s

GlobList with 158 entries:
  $ time clang-tidy-old -checks=-*,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,modernize-use-override /tmp/q.cc -- -Wshadow
  200000 warnings generated.
  Suppressed 200000 warnings (200000 with check filters).

  real    0m13.920s
  user    0m13.636s
  sys     0m0.104s

With the patch runtime is practically independent from the length of the GlobList:
  $ time clang-tidy-new -checks=-*,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,modernize-use-override /tmp/q.cc -- -Wshadow
  200000 warnings generated.
  Suppressed 200000 warnings (200000 with check filters).

  real    0m2.300s
  user    0m2.104s
  sys     0m0.044s

llvm-svn: 303321
2017-05-18 01:13:51 +00:00
..
change-namespace [change-namespace] avoid adding leading '::' when possible. 2017-03-21 12:41:59 +00:00
clang-apply-replacements Update tools to use new getStyle API 2017-01-17 00:13:32 +00:00
clang-move [clang-move] Find template class forward declarations more precisely. 2017-05-02 12:15:11 +00:00
clang-query modernize-use-auto NFC fixes 2016-12-14 15:29:23 +00:00
clang-rename clang-rename: fix formatting 2017-04-23 16:07:06 +00:00
clang-reorder-fields [clang-rename] Fix handling of unchanged files 2016-09-17 17:08:47 +00:00
clang-tidy [clang-tidy] Optimize GlobList::contains 2017-05-18 01:13:51 +00:00
clang-tidy-vs Remove 'misc-pointer-and-integral-operation' clang-tidy check. The only cases 2016-10-21 21:50:28 +00:00
clangd Added missing includes in clangd to fix the build. 2017-05-16 15:23:55 +00:00
docs [clang-tidy] Add "emplace_back" detection in inefficient-vector-operation. 2017-05-16 10:39:55 +00:00
include-fixer Recommit "[include-fixer] Don't throw exception when parsing unknown ar… …guments in vim script." 2017-05-17 14:13:59 +00:00
modularize Fix memory leak by using unique_ptr 2017-02-11 05:25:21 +00:00
pp-trace Fix API breaks 2017-04-26 20:58:03 +00:00
test [clang-tidy] Add "emplace_back" detection in inefficient-vector-operation. 2017-05-16 10:39:55 +00:00
tool-template [clang-tools-extra] Format sources with clang-format. NFC. 2016-11-08 07:50:19 +00:00
unittests [clang-move] Find template class forward declarations more precisely. 2017-05-02 12:15:11 +00:00
.arcconfig Upgrade all the .arcconfigs to https. 2016-07-14 13:15:37 +00:00
.gitignore
CMakeLists.txt Add a prototype for clangd 2017-02-07 10:28:20 +00:00
CODE_OWNERS.TXT Updating the code owners list. 2015-09-02 20:00:41 +00:00
LICENSE.TXT Rename the clang-tidy safety module to be hicpp, for the High-Integrity C++ coding standard from PRQA. 2017-03-19 17:23:23 +00:00
README.txt Update references to new lists.llvm.org mailing lists. 2015-08-05 03:56:44 +00:00

README.txt

//===----------------------------------------------------------------------===//
// Clang Tools repository
//===----------------------------------------------------------------------===//

Welcome to the repository of extra Clang Tools.  This repository holds tools
that are developed as part of the LLVM compiler infrastructure project and the
Clang frontend.  These tools are kept in a separate "extra" repository to
allow lighter weight checkouts of the core Clang codebase.

This repository is only intended to be checked out inside of a full LLVM+Clang
tree, and in the 'tools/extra' subdirectory of the Clang checkout.

All discussion regarding Clang, Clang-based tools, and code in this repository
should be held using the standard Clang mailing lists:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

Code review for this tree should take place on the standard Clang patch and
commit lists:
  http://lists.llvm.org/mailman/listinfo/cfe-commits

If you find a bug in these tools, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/