[llvm] [Memory] Call __clear_cache in InvalidateInstructionCache on LoongArch (PR #67285)

[Lu Weining via llvm-commits]

https://github.com/SixWeining created https://github.com/llvm/llvm-project/pull/67285

As the comments of `InvalidateInstructionCache`: Before the JIT can run a block of code that has been emitted it must invalidate the instruction cache on some platforms. I think it applies to LoongArch as LoongArch has a weak memory-model. But I'm not able to write a test to demonstrate this issue. Perhaps self-modifing code should be wrote?

>From 4dcf3fc621592daf6d81893df8b5d644c606d7f2 Mon Sep 17 00:00:00 2001
From: Weining Lu <luweining at loongson.cn>
Date: Mon, 25 Sep 2023 13:42:00 +0800
Subject: [PATCH] [Memory] Call __clear_cache in InvalidateInstructionCache on
 LoongArch

As the comments of `InvalidateInstructionCache`: Before the JIT can
run a block of code that has been emitted it must invalidate the
instruction cache on some platforms. I think it applies to LoongArch
as LoongArch has a weak memory-model. But I'm not able to write a test
to demonstrate this issue. Perhaps self-modifing code should be wrote?
---
 llvm/lib/Support/Unix/Memory.inc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
index 4c8f6b2ea7d3a09..69bd1164343da74 100644
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -237,7 +237,8 @@ void Memory::InvalidateInstructionCache(const void *Addr, size_t Len) {
   for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
     asm volatile("icbi 0, %0" : : "r"(Line));
   asm volatile("isync");
-#elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) &&       \
+#elif (defined(__arm__) || defined(__aarch64__) || defined(__loongarch__) ||   \
+       defined(__mips__)) &&                                                   \
     defined(__GNUC__)
   // FIXME: Can we safely always call this for __GNUC__ everywhere?
   const char *Start = static_cast<const char *>(Addr);