[llvm] [Support/rpmalloc] Updated fake atomics with Interlocked functions (PR #148303)

[Dmitry Vasilyev via llvm-commits]

https://github.com/slydiman updated https://github.com/llvm/llvm-project/pull/148303

>From f300dcbf8657e61e01777662336c34a172f5911b Mon Sep 17 00:00:00 2001
From: Dmitry Vassiliev <dvassiliev at accesssoftek.com>
Date: Fri, 11 Jul 2025 16:47:37 +0400
Subject: [PATCH] [Support/rpmalloc] Updated fake atomics with Interlocked
 functions

Most atomic functions used Interlocked functions in case of MSVC (since MSVC does not do C11 yet).
But few load/store functions are dummy.
Use Interlocked functions for these atomics to ensure they are thread-safe.

This PR fixes #146205.
---
 llvm/lib/Support/rpmalloc/rpmalloc.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Support/rpmalloc/rpmalloc.c b/llvm/lib/Support/rpmalloc/rpmalloc.c
index a06d3cdb5b52e..6f8b29e31e8ca 100644
--- a/llvm/lib/Support/rpmalloc/rpmalloc.c
+++ b/llvm/lib/Support/rpmalloc/rpmalloc.c
@@ -275,9 +275,11 @@ typedef volatile long atomic32_t;
 typedef volatile long long atomic64_t;
 typedef volatile void *atomicptr_t;
 
-static FORCEINLINE int32_t atomic_load32(atomic32_t *src) { return *src; }
+static FORCEINLINE int32_t atomic_load32(atomic32_t *src) {
+  return (int32_t)InterlockedOr(src, 0);
+}
 static FORCEINLINE void atomic_store32(atomic32_t *dst, int32_t val) {
-  *dst = val;
+  InterlockedExchange(dst, val);
 }
 static FORCEINLINE int32_t atomic_incr32(atomic32_t *val) {
   return (int32_t)InterlockedIncrement(val);
@@ -293,20 +295,22 @@ static FORCEINLINE int atomic_cas32_acquire(atomic32_t *dst, int32_t val,
   return (InterlockedCompareExchange(dst, val, ref) == ref) ? 1 : 0;
 }
 static FORCEINLINE void atomic_store32_release(atomic32_t *dst, int32_t val) {
-  *dst = val;
+  InterlockedExchange(dst, val);
+}
+static FORCEINLINE int64_t atomic_load64(atomic64_t *src) {
+  return (int64_t)InterlockedOr64(src, 0);
 }
-static FORCEINLINE int64_t atomic_load64(atomic64_t *src) { return *src; }
 static FORCEINLINE int64_t atomic_add64(atomic64_t *val, int64_t add) {
   return (int64_t)InterlockedExchangeAdd64(val, add) + add;
 }
 static FORCEINLINE void *atomic_load_ptr(atomicptr_t *src) {
-  return (void *)*src;
+  return InterlockedCompareExchangePointer(src, 0, 0);
 }
 static FORCEINLINE void atomic_store_ptr(atomicptr_t *dst, void *val) {
-  *dst = val;
+  InterlockedExchangePointer(dst, val);
 }
 static FORCEINLINE void atomic_store_ptr_release(atomicptr_t *dst, void *val) {
-  *dst = val;
+  InterlockedExchangePointer(dst, val);
 }
 static FORCEINLINE void *atomic_exchange_ptr_acquire(atomicptr_t *dst,
                                                      void *val) {