[all-commits] [llvm/llvm-project] a9cbe5: [X86] Fix stack alignment on 32-bit Solaris/x86

[rorth via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: a9cbe5cf30e386a4f44981f5bf9e1862ad36574d
      https://github.com/llvm/llvm-project/commit/a9cbe5cf30e386a4f44981f5bf9e1862ad36574d
  Author: Rainer Orth <ro at gcc.gnu.org>
  Date:   2020-09-17 (Thu, 17 Sep 2020)

  Changed paths:
    M compiler-rt/test/ubsan/TestCases/TypeCheck/vptr.cpp
    M llvm/lib/Target/X86/X86Subtarget.cpp
    M llvm/test/CodeGen/X86/stack-align2.ll

  Log Message:
  -----------
  [X86] Fix stack alignment on 32-bit Solaris/x86

On Solaris/x86, several hundred 32-bit tests `FAIL`, all in the same way:

  env ASAN_OPTIONS=halt_on_error=false ./halt_on_error_suppress_equal_pcs.cpp.tmp
  Segmentation Fault (core dumped)

They segfault during startup:

  Thread 2 received signal SIGSEGV, Segmentation fault.
  [Switching to Thread 1 (LWP 1)]
  0x080f21f0 in __sanitizer::internal_mmap(void*, unsigned long, int, int, int, unsigned long long) () at /vol/llvm/src/llvm-project/dist/compiler-rt/lib/sanitizer_common/sanitizer_solaris.cpp:65
  65	                             int prot, int flags, int fd, OFF_T offset) {
  1: x/i $pc
  => 0x80f21f0 <_ZN11__sanitizer13internal_mmapEPvmiiiy+16>:	movaps 0x30(%esp),%xmm0
  (gdb) p/x $esp
  $3 = 0xfeffd488

The problem is that `movaps` expects 16-byte alignment, while 32-bit Solaris/x86
only guarantees 4-byte alignment following the i386 psABI.

This patch updates `X86Subtarget::initSubtargetFeatures` accordingly,
handles Solaris/x86 in the corresponding testcase, and allows for some
variation in address alignment in
`compiler-rt/test/ubsan/TestCases/TypeCheck/vptr.cpp`.

Tested on `amd64-pc-solaris2.11` and `x86_64-pc-linux-gnu`.

Differential Revision: https://reviews.llvm.org/D87615