[compiler-rt] 2b0f5df - [builtins][Mips] Un-break FreeBSD build of __clear_cache

[Jessica Clarke via llvm-commits]

Author: Jessica Clarke
Date: 2023-07-22T23:01:21+01:00
New Revision: 2b0f5df7b4e01d5b9b380fd72a19df021b9a3b98

URL: https://github.com/llvm/llvm-project/commit/2b0f5df7b4e01d5b9b380fd72a19df021b9a3b98
DIFF: https://github.com/llvm/llvm-project/commit/2b0f5df7b4e01d5b9b380fd72a19df021b9a3b98.diff

LOG: [builtins][Mips] Un-break FreeBSD build of __clear_cache

Commit 674a17e9bbe8 ("MIPS/compiler_rt: use synci to flush icache on
r6") completely removed the OS-specific guards under the guise of "For
pre-r6, we can use cacheflush libc function, which is same on Linux and
FreeBSD." However, the code in question had guards for Linux and
OpenBSD, not Linux and FreeBSD, and FreeBSD does not have a cacheflush
libc function as claimed, so this was neither the statement they
intended to make nor was it sufficient justification for making the code
completely unconditional. Whilst the upcoming FreeBSD 14 release has
dropped support for MIPS, FreeBSD 13 has support for it.

Fix this by only calling cacheflush on the OSes where it was previously
called, and not on other OSes where it either definitely isn't available
(FreeBSD) or is unknown (any other OS than the three mentioned in this
commit).

Added: 
    

Modified: 
    compiler-rt/lib/builtins/clear_cache.c

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/builtins/clear_cache.c b/compiler-rt/lib/builtins/clear_cache.c
index 8993761eb3d42c..54cbda059315a7 100644
--- a/compiler-rt/lib/builtins/clear_cache.c
+++ b/compiler-rt/lib/builtins/clear_cache.c
@@ -110,10 +110,14 @@ void __clear_cache(void *start, void *end) {
                      "jr.hb $at\n"
                      "move $at, $0\n"
                      ".set at");
-#else
+#elif defined(__linux__) || defined(__OpenBSD__)
     // Pre-R6 may not be globalized. And some implementations may give strange
     // synci_step. So, let's use libc call for it.
     cacheflush(start, end_int - start_int, BCACHE);
+#else
+    (void)start_int;
+    (void)end_int;
+    compilerrt_abort();
 #endif
   }
 #elif defined(__aarch64__) && !defined(__APPLE__)