On Tue, 2018-03-20 at 23:32 +0100, Mark Wielaard wrote: > On Sun, Mar 18, 2018 at 01:43:23AM +0100, Mark Wielaard wrote: > > If possible use process_vm_readv to read 4K blocks instead of fetching > > each word individually with ptrace. For unwinding this often means we > > only have to do one process_vm_readv of the stack instead of dozens of > > ptrace calls. There is one 4K cache per process, cleared whenever a > > thread is detached. > > It seems to work well, but the GCC undefined sanitizer > (configure --enable-sanitize-undefined) found an issue in the > run-backtrace-native-biarch.sh testcase (from x86_64 to i686) > when reading unaligned data. To fix that don't assign to the > Dwarf_Word directly when unaligned, but use memcpy (which gcc > seems to inline).
I pushed this to master now. Adding some comments about the word size being actually architecture defined even though we use a 64bit Dwarf_Word everywhere. Cheers, Mark
