[PATCH v2 0/4] perf hashmap: Separate perf's hashmap code from libbpf

[Ian Rogers]

The hashmap code as-is violates the C specification meaning
 -fno-strict-aliasing is required or fixes sent in:
https://lore.kernel.org/lkml/20260321024446.692008-1-irogers@xxxxxxxxxx/
    
We're looking to not build perf with -fno-strict-aliasing:
https://lore.kernel.org/lkml/20260320224248.536449-1-irogers@xxxxxxxxxx/
    
There is also the continual problem with hashmap using errptrs rather
than errno introducing subtle bugs as shown in commits,
  d05073adda0f perf trace: Avoid an ERR_PTR in syscall_stats
  96f202eab813 perf trace: Fix IS_ERR() vs NULL check bug
  9f3c16a430e8 perf expr: Fix return value of ids__new()
but there are additional fixes on the mailing list.
https://lore.kernel.org/lkml/20250805063209.3678359-1-linmq006@xxxxxxxxx/
    
Allow the perf version of hashmap diverge from libbpf's so that we can
fix its issues. This means that perf has a dependency on libbpf that
has strict aliasing violations, no -fno-strict-alias or the fixes, but
you can bring a horse to water, you can't make it drink.

v1: https://lore.kernel.org/lkml/20260321024446.692008-1-irogers@xxxxxxxxxx/

Ian Rogers (4):
  perf build: Don't check difference of perf and libbpf hashmap
  perf hashmap: Rename hashmap to perf_hashmap to avoid libbpf conflict
  perf hashmap: Fix strict aliasing violations in hashmap
  perf hashmap: Remove errptr usage from hashmap

 tools/perf/builtin-ftrace.c           |  20 ++--
 tools/perf/builtin-trace.c            |  32 +++---
 tools/perf/check-headers.sh           |   4 -
 tools/perf/tests/expr.c               |  68 ++++++-------
 tools/perf/tests/pmu-events.c         |   8 +-
 tools/perf/ui/browsers/annotate.c     |  16 +--
 tools/perf/util/Build                 |   9 --
 tools/perf/util/annotate.c            |  18 ++--
 tools/perf/util/annotate.h            |   6 +-
 tools/perf/util/bpf-trace-summary.c   |  30 +++---
 tools/perf/util/bpf_lock_contention.c |  14 +--
 tools/perf/util/evsel.c               |   8 +-
 tools/perf/util/evsel.h               |   4 +-
 tools/perf/util/expr.c                |  68 ++++++-------
 tools/perf/util/expr.h                |  12 +--
 tools/perf/util/expr.y                |   2 +-
 tools/perf/util/fncache.c             |  16 +--
 tools/perf/util/ftrace.h              |   2 +-
 tools/perf/util/hashmap.c             | 126 +++++++++++------------
 tools/perf/util/hashmap.h             | 138 +++++++++++++-------------
 tools/perf/util/hwmon_pmu.c           |  44 ++++----
 tools/perf/util/metricgroup.c         |  30 +++---
 tools/perf/util/pmu.c                 |  30 +++---
 tools/perf/util/pmu.h                 |   4 +-
 tools/perf/util/s390-sample-raw.c     |  14 +--
 tools/perf/util/stat.c                |  10 +-
 tools/perf/util/threads.c             |  24 ++---
 tools/perf/util/threads.h             |   2 +-
 28 files changed, 379 insertions(+), 380 deletions(-)

-- 
2.53.0.959.g497ff81fa9-goog