[compiler-rt][builtins] Provide __clear_cache for SPARC

While working on https://reviews.llvm.org/D40900, two tests were failing since __clear_cache
aborted.  While libgcc's __clear_cache is just empty, this only happens because
gcc (in gcc/config/sparc/sparc.c (sparc32_initialize_trampoline, sparc64_initialize_trampoline))
emits flush insns directly.

The following patch mimics that.

Tested on sparcv9-sun-solaris2.11.

Differential Revision: https://reviews.llvm.org/D64496

llvm-svn: 366822

1 files changed, 10 insertions, 0 deletions

diff --git a/compiler-rt/lib/builtins/clear_cache.c b/compiler-rt/lib/builtins/clear_cache.c
index 76dc1968cc7..079b245c3fa 100644
--- a/compiler-rt/lib/builtins/clear_cache.c
+++ b/compiler-rt/lib/builtins/clear_cache.c
@@ -173,6 +173,16 @@ void __clear_cache(void *start, void *end) {
   for (uintptr_t line = start_line; line < end_line; line += line_size)
     __asm__ volatile("icbi 0, %0" : : "r"(line));
   __asm__ volatile("isync");
+#elif defined(__sparc__)
+  const size_t dword_size = 8;
+  const size_t len = (uintptr_t)end - (uintptr_t)start;
+
+  const uintptr_t mask = ~(dword_size - 1);
+  const uintptr_t start_dword = ((uintptr_t)start) & mask;
+  const uintptr_t end_dword = ((uintptr_t)start + len + dword_size - 1) & mask;
+
+  for (uintptr_t dword = start_dword; dword < end_dword; dword += dword_size)
+    __asm__ volatile("flush %0" : : "r"(dword));
 #else
 #if __APPLE__
   // On Darwin, sys_icache_invalidate() provides this functionality