[compiler-rt] [compiler-rt] Avoid defining _KERNEL on FreeBSD (PR #143116)

[Jessica Clarke via llvm-commits]

https://github.com/jrtc27 updated https://github.com/llvm/llvm-project/pull/143116

>From a9235ae78fd60524be1e225cd9ee45d0c8236a9e Mon Sep 17 00:00:00 2001
From: Jessica Clarke <jrtc27 at jrtc27.com>
Date: Fri, 6 Jun 2025 13:15:15 +0100
Subject: [PATCH] [compiler-rt] Don't handle Linux-specific shmctl commands in
 sanitizer

Despite being defined in the system headers, these commands are not in
fact part of the FreeBSD system call interface. They exist solely for
the Linuxulator, i.e. running Linux binaries on FreeBSD, and any attempt
to use them from a FreeBSD binary will return EINVAL. The fact we needed
to define _KERNEL (which, as the name implies, means we are compiling
the kernel) to even get the definition of shminfo should have been a
strong indicator that IPC_INFO at least was not a userspace interface.
---
 .../sanitizer_platform_limits_freebsd.cpp            | 10 +---------
 .../sanitizer_platform_limits_freebsd.h              | 12 +++++++-----
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
index 4940062eeae47..4c1e005289230 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
@@ -29,6 +29,7 @@
 #include <sys/mtio.h>
 #include <sys/ptrace.h>
 #include <sys/resource.h>
+#include <sys/shm.h>
 #include <sys/signal.h>
 #include <sys/socket.h>
 #include <sys/sockio.h>
@@ -87,10 +88,6 @@
 #include <wchar.h>
 #include <wordexp.h>
 
-#define _KERNEL  // to declare 'shminfo' structure
-#include <sys/shm.h>
-#undef _KERNEL
-
 #undef IOC_DIRMASK
 
 // Include these after system headers to avoid name clashes and ambiguities.
@@ -141,8 +138,6 @@ unsigned struct_timeb_sz = sizeof(struct timeb);
 unsigned struct_msqid_ds_sz = sizeof(struct msqid_ds);
 unsigned struct_mq_attr_sz = sizeof(struct mq_attr);
 unsigned struct_statvfs_sz = sizeof(struct statvfs);
-unsigned struct_shminfo_sz = sizeof(struct shminfo);
-unsigned struct_shm_info_sz = sizeof(struct shm_info);
 unsigned struct_regmatch_sz = sizeof(regmatch_t);
 unsigned struct_regex_sz = sizeof(regex_t);
 unsigned struct_fstab_sz = sizeof(struct fstab);
@@ -156,9 +151,6 @@ const uptr sig_err = (uptr)SIG_ERR;
 const uptr sa_siginfo = (uptr)SA_SIGINFO;
 
 int shmctl_ipc_stat = (int)IPC_STAT;
-int shmctl_ipc_info = (int)IPC_INFO;
-int shmctl_shm_info = (int)SHM_INFO;
-int shmctl_shm_stat = (int)SHM_STAT;
 unsigned struct_utmpx_sz = sizeof(struct utmpx);
 
 int map_fixed = MAP_FIXED;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
index 8ce73f206fd88..382b67ce78ebd 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
@@ -419,12 +419,14 @@ struct __sanitizer_wordexp_t {
 
 typedef void __sanitizer_FILE;
 
-extern unsigned struct_shminfo_sz;
-extern unsigned struct_shm_info_sz;
 extern int shmctl_ipc_stat;
-extern int shmctl_ipc_info;
-extern int shmctl_shm_info;
-extern int shmctl_shm_stat;
+
+// This simplifies generic code
+#define struct_shminfo_sz -1
+#define struct_shm_info_sz -1
+#define shmctl_shm_stat -1
+#define shmctl_ipc_info -1
+#define shmctl_shm_info -1
 
 extern unsigned struct_utmpx_sz;