[PATCH] D68720: Support -fstack-clash-protection for x86

Tue Oct 15 05:55:43 PDT 2019

serge-sans-paille added a comment.

Another test run on an x264 encoder (source: https://openbenchmarking.org/test/pts/x264)

Compiled with -O2 and with or without -fstack-clash-protection; Run without threads (`x265 --pools 1 -F 1 ./Bosphorus_1920x1080_120fps_420_8bit_YUV.y4m /dev/null`)

**Clang**

  baseline:  318.60s 
  protection:  317.72s

So no performance impact beyond noise.

The compilation inserts 44 inline probes in 9 functions.

**gcc**

Out of comparison, with gcc 8.2 (yeah, it's a bit old), I get (same flags & setup)

  baseline : 417.53 sec
  protected : 412.6 sec 

The compilations inserts inline probes in 22 functions.
So gcc inserts more probes, the impact on performance is equally surprising. I need to gather more points to get some statistical informations there.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720