| Message ID | 1676994522-1557-1-git-send-email-alan.maguire@oracle.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | dwarves: improvements/fixes to BTF function skip logic | expand |
On Tue, Feb 21, 2023 at 03:48:39PM +0000, Alan Maguire wrote: > As discussed in [1], there are a few issues with how we determine > whether to skip functions for BTF encoding: > > - when detecting unexpected registers, functions which have > struct parameters need to be skipped as they can use > multiple registers to pass the struct, and as a result > later parameters use unexpected registers. However, > struct detection does not always work; it needs to be fixed for > const struct parameters and cases where a parameter references > the original parameter (which has the type info) via abstract > origin (patch 1) > - when looking for unexpected registers, location lists are not > supported. Fix that by using dwarf_getlocations() (patch 2). > - when marking parameters as using unexpected registers, we should > stick to the case where we expect register x and register y is > used; other cases such as optimized-out parameters are no > guarantee that we were not _passed_ the correct parameters > (patch 3). > > This series can be applied on top of the dwarves "next" branch, > as a follow-on to [2] > > [1] https://lore.kernel.org/bpf/20230220190335.bk6jzayfqivsh7rv@macbook-pro-6.dhcp.thefacebook.com/ > [2] https://lore.kernel.org/bpf/1676675433-10583-1-git-send-email-alan.maguire@oracle.com/ > > Alan Maguire (3): > dwarf_loader: fix detection of struct parameters > dwarf_loader: fix parameter location retrieval for location lists > dwarf_loader: only mark parameter as using an unexpected register when > it does I'm getting more functions in with this patchset 1666 for gcc (with 61678, without 60012) 9390 for clang (with 62128, without 52738) but no duplicates and selftests are passing Tested-by: Jiri Olsa <jolsa@kernel.org> jirka > > dwarf_loader.c | 30 ++++++++++++++++++------------ > 1 file changed, 18 insertions(+), 12 deletions(-) > > -- > 2.31.1 >
Em Thu, Feb 23, 2023 at 11:10:07PM +0100, Jiri Olsa escreveu: > On Tue, Feb 21, 2023 at 03:48:39PM +0000, Alan Maguire wrote: > > As discussed in [1], there are a few issues with how we determine > > whether to skip functions for BTF encoding: > > > > - when detecting unexpected registers, functions which have > > struct parameters need to be skipped as they can use > > multiple registers to pass the struct, and as a result > > later parameters use unexpected registers. However, > > struct detection does not always work; it needs to be fixed for > > const struct parameters and cases where a parameter references > > the original parameter (which has the type info) via abstract > > origin (patch 1) > > - when looking for unexpected registers, location lists are not > > supported. Fix that by using dwarf_getlocations() (patch 2). > > - when marking parameters as using unexpected registers, we should > > stick to the case where we expect register x and register y is > > used; other cases such as optimized-out parameters are no > > guarantee that we were not _passed_ the correct parameters > > (patch 3). > > > > This series can be applied on top of the dwarves "next" branch, > > as a follow-on to [2] > > > > [1] https://lore.kernel.org/bpf/20230220190335.bk6jzayfqivsh7rv@macbook-pro-6.dhcp.thefacebook.com/ > > [2] https://lore.kernel.org/bpf/1676675433-10583-1-git-send-email-alan.maguire@oracle.com/ > > > > Alan Maguire (3): > > dwarf_loader: fix detection of struct parameters > > dwarf_loader: fix parameter location retrieval for location lists > > dwarf_loader: only mark parameter as using an unexpected register when > > it does > > I'm getting more functions in with this patchset > > 1666 for gcc (with 61678, without 60012) > 9390 for clang (with 62128, without 52738) > > but no duplicates and selftests are passing > > Tested-by: Jiri Olsa <jolsa@kernel.org> Oh, I saw this and your comment about not using the branch 'next' and thought these were already there :-\ I reviewed the patches now and I'm testing them, soon will push to the 'next' branch for some testing on the libbpf CI. - Arnaldo
As discussed in [1], there are a few issues with how we determine whether to skip functions for BTF encoding: - when detecting unexpected registers, functions which have struct parameters need to be skipped as they can use multiple registers to pass the struct, and as a result later parameters use unexpected registers. However, struct detection does not always work; it needs to be fixed for const struct parameters and cases where a parameter references the original parameter (which has the type info) via abstract origin (patch 1) - when looking for unexpected registers, location lists are not supported. Fix that by using dwarf_getlocations() (patch 2). - when marking parameters as using unexpected registers, we should stick to the case where we expect register x and register y is used; other cases such as optimized-out parameters are no guarantee that we were not _passed_ the correct parameters (patch 3). This series can be applied on top of the dwarves "next" branch, as a follow-on to [2] [1] https://lore.kernel.org/bpf/20230220190335.bk6jzayfqivsh7rv@macbook-pro-6.dhcp.thefacebook.com/ [2] https://lore.kernel.org/bpf/1676675433-10583-1-git-send-email-alan.maguire@oracle.com/ Alan Maguire (3): dwarf_loader: fix detection of struct parameters dwarf_loader: fix parameter location retrieval for location lists dwarf_loader: only mark parameter as using an unexpected register when it does dwarf_loader.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)