[compiler-rt] [sanitizer_common] Remove <procfs.h> workaround on Solaris (PR #142758)

[Rainer Orth via llvm-commits]

https://github.com/rorth created https://github.com/llvm/llvm-project/pull/142758

`sanitizer_procmaps_solaris.cpp` currently uses `#undef _FILE_OFFSET_BITS` to hack around the fact that old versions of Solaris `<procfs.h>` don't work in a largefile environment:

```
/usr/include/sys/procfs.h:42:2: error: #error "Cannot use procfs in the large file compilation environment"
   42 | #error  "Cannot use procfs in the large file compilation environment"
      |  ^~~~~
```

However, this is no longer an issue on either Solaris 11.4 or Illumos.  The workaround only existed for the benefit of Solaris 11.3.  While that had never been supported by LLVM, the sanitizer runtime libs were imported into GCC's `libsanitzer`.  With the removal of Solaris 11.3 support in GCC 15, this is no longer an issue and the workaround can be removed.

Tested on `amd64-pc-solaris2.11` and `sparcv9-sun-solaris2.11`.

>From 2315feb282bd73d121521702e3eab429fca25af9 Mon Sep 17 00:00:00 2001
From: Rainer Orth <ro at gcc.gnu.org>
Date: Wed, 4 Jun 2025 11:46:32 +0200
Subject: [PATCH] [sanitizer_common] Remove <procfs.h> workaround on Solaris

`sanitizer_procmaps_solaris.cpp` currently uses `#undef _FILE_OFFSET_BITS`
to hack around the fact that old versions of Solaris `<procfs.h>` don't
work in a largefile environment:

```
/usr/include/sys/procfs.h:42:2: error: #error "Cannot use procfs in the large file compilation environment"
   42 | #error  "Cannot use procfs in the large file compilation environment"
      |  ^~~~~
```

However, this is no longer an issue on either Solaris 11.4 or Illumos.  The
workaround only existed for the benefit of Solaris 11.3.  While that had
never been supported by LLVM, the sanitizer runtime libs were imported into
GCC's `libsanitzer`.  With the removal of Solaris 11.3 support in GCC 15,
this is no longer an issue and the workaround can be removed.

Tested on `amd64-pc-solaris2.11` and `sparcv9-sun-solaris2.11`.
---
 .../lib/sanitizer_common/sanitizer_procmaps_solaris.cpp        | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
index 80b8158f43db9..452b30308be91 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
@@ -9,9 +9,6 @@
 // Information about the process mappings (Solaris-specific parts).
 //===----------------------------------------------------------------------===//
 
-// Before Solaris 11.4, <procfs.h> doesn't work in a largefile environment.
-#undef _FILE_OFFSET_BITS
-
 // Avoid conflict between `_TIME_BITS` defined vs. `_FILE_OFFSET_BITS`
 // undefined in some Linux configurations.
 #undef _TIME_BITS