[all-commits] [llvm/llvm-project] 947f96: Fix sanitizer-common build with glibc 2.31

[Evgenii Stepanov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 947f9692440836dcb8d88b74b69dd379d85974ce
      https://github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce
  Author: Evgenii Stepanov <eugenis at google.com>
  Date:   2019-11-25 (Mon, 25 Nov 2019)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
    M compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h

  Log Message:
  -----------
  Fix sanitizer-common build with glibc 2.31

Summary:
As mentioned in D69104, glibc changed ABI recently with the [[ https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=2f959dfe849e0646e27403f2e4091536496ac0f0| 2f959dfe ]] change.
D69104 dealt with just 32-bit ARM, but that is just one of the many affected architectures.
E.g. x86_64, i?86, riscv64, sparc 32-bit, s390 31-bit are affected too (and various others).

This patch instead of adding a long list of further architectures that wouldn't be checked ever next to arm 32-bit changes the structures to match the 2.31 layout and performs the checking on Linux for ipc_perm mode position/size only on non-Linux or on Linux with glibc 2.31 or later.  I think this matches what is done for aarch64 already.
If needed, we could list architectures that haven't changed ABI (e.g. powerpc), so that they would be checked even with older glibcs.  AFAIK sanitizers don't actually use ipc_perm.mode and
so all they care about is the size and alignment of the whole structure.

Note, s390 31-bit and arm 32-bit big-endian changed ABI even further, there will now be shmctl with old symbol version and shmctl@@GLIBC_2.31 which will be incompatible.  I'm afraid this isn't really solvable unless the sanitizer libraries are symbol versioned and use matching symbol versions to glibc symbols for stuff they intercept, plus use dlvsym.
This patch doesn't try to address that.

Patch by Jakub Jelinek.

Reviewers: kcc, eugenis, dvyukov

Reviewed By: eugenis

Subscribers: jyknight, kristof.beyls, fedor.sergeev, simoncook, PkmX, s.egerton, steven.zhang, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D70662