Slightly improve x86 unwind intensive workload.
e.g. perf/memrw is improved by 2% to 3% with this patch.
The unwinding code on x86 is trying to unwind using
either the %ebp-chain or CFI unwinding.
If these 2 techniques fail, then it tries to unwind
using FPO (PDB) debug info.
However, unless running wine or similar, there will never be
such FPO/PDB info.
The function VG_(use_FPO_info) is thus called for nothing
for each 'end of stack'. This function scans all the loaded di
to find a debug info that has some FP, to not find anything.
With this patch, the unwind code on x86 will only call VG_(use_FPO_info) if
some FPO/PDB info was loaded.
The fact that FPO/PDB info was loaded is cached and updated similarly to
cfi cache : each time new debug info is loaded, the cache value is refreshed
using the debuginfo generation.
The patch also changes the name of VG_(CF_info_generation)
to VG_(debuginfo_generation), as this generation is changed for
any kind of load or unload of debug info, not only for CFI based debug
info
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15293 a5019735-40e9-0310-863c-91ae7b9d1cf9
3 files changed