From be05af79fb8d9a6f88e8ad384675df9cfad23069 Mon Sep 17 00:00:00 2001
From: Huang Qi <huangqi3@xiaomi.com>
Date: Sat, 18 Nov 2023 08:59:58 +0800
Subject: [PATCH] Refine atomic operation flags in bh_atomic.h (#2780)

---
 core/shared/utils/bh_atomic.h | 104 +++++++++++++++++++++++-----------
 1 file changed, 71 insertions(+), 33 deletions(-)

diff --git a/core/shared/utils/bh_atomic.h b/core/shared/utils/bh_atomic.h
index ac3417c30..5744a64c0 100644
--- a/core/shared/utils/bh_atomic.h
+++ b/core/shared/utils/bh_atomic.h
@@ -47,6 +47,19 @@ extern "C" {
 typedef uint32 bh_atomic_32_t;
 typedef uint16 bh_atomic_16_t;
 
+/* The flag can be defined by the user if the platform
+ * supports atomic 32-bit operations.
+ * If left undefined, it will be automatically defined
+ * according to the platform.
+ */
+#ifdef WASM_UINT32_IS_ATOMIC
+#define BH_ATOMIC_32_IS_ATOMIC WASM_UINT32_IS_ATOMIC
+#endif /* WASM_UINT32_IS_ATOMIC */
+
+#ifdef WASM_UINT16_IS_ATOMIC
+#define BH_ATOMIC_16_IS_ATOMIC WASM_UINT16_IS_ATOMIC
+#endif /* WASM_UINT16_IS_ATOMIC */
+
 #if defined(__GNUC_PREREQ)
 #if __GNUC_PREREQ(4, 7)
 #define CLANG_GCC_HAS_ATOMIC_BUILTIN
@@ -58,7 +71,38 @@ typedef uint16 bh_atomic_16_t;
 #endif
 
 #if defined(CLANG_GCC_HAS_ATOMIC_BUILTIN)
+#ifndef BH_ATOMIC_32_IS_ATOMIC
 #define BH_ATOMIC_32_IS_ATOMIC 1
+#endif
+#ifndef BH_ATOMIC_16_IS_ATOMIC
+#define BH_ATOMIC_16_IS_ATOMIC 1
+#endif
+#else
+#ifndef BH_ATOMIC_32_IS_ATOMIC
+#define BH_ATOMIC_32_IS_ATOMIC 0
+#endif
+#ifndef BH_ATOMIC_16_IS_ATOMIC
+#define BH_ATOMIC_16_IS_ATOMIC 0
+#endif
+#endif
+
+/* Force disable atomic 16-bit operations on bare-metal RISC-V
+ * because the 16-bit atomic operations is emulated by 32-bit
+ * atomic operations, which has linkage problem on current toolchain:
+ * in function `shared_memory_inc_reference':
+ * wasm_shared_memory.c:85:(.text.shared_memory_inc_reference+0x10): undefined
+ * reference to `__atomic_fetch_add_2'
+ */
+#ifndef WASM_UINT16_IS_ATOMIC
+#if !defined(__linux__) && !defined(__FreeBSD__) && !defined(__NetBSD__) \
+    && !defined(__OpenBSD__) && defined(__riscv)
+#undef BH_ATOMIC_16_IS_ATOMIC
+#define BH_ATOMIC_16_IS_ATOMIC 0
+#endif
+#endif
+
+#if BH_ATOMIC_32_IS_ATOMIC != 0
+
 #define BH_ATOMIC_32_LOAD(v) __atomic_load_n(&(v), __ATOMIC_SEQ_CST)
 #define BH_ATOMIC_32_STORE(v, val) __atomic_store_n(&(v), val, __ATOMIC_SEQ_CST)
 #define BH_ATOMIC_32_FETCH_OR(v, val) \
@@ -70,18 +114,8 @@ typedef uint16 bh_atomic_16_t;
 #define BH_ATOMIC_32_FETCH_SUB(v, val) \
     __atomic_fetch_sub(&(v), (val), __ATOMIC_SEQ_CST)
 
-#define BH_ATOMIC_16_IS_ATOMIC 1
-#define BH_ATOMIC_16_LOAD(v) __atomic_load_n(&(v), __ATOMIC_SEQ_CST)
-#define BH_ATOMIC_16_STORE(v, val) __atomic_store_n(&(v), val, __ATOMIC_SEQ_CST)
-#define BH_ATOMIC_16_FETCH_OR(v, val) \
-    __atomic_fetch_or(&(v), (val), __ATOMIC_SEQ_CST)
-#define BH_ATOMIC_16_FETCH_AND(v, val) \
-    __atomic_fetch_and(&(v), (val), __ATOMIC_SEQ_CST)
-#define BH_ATOMIC_16_FETCH_ADD(v, val) \
-    __atomic_fetch_add(&(v), (val), __ATOMIC_SEQ_CST)
-#define BH_ATOMIC_16_FETCH_SUB(v, val) \
-    __atomic_fetch_sub(&(v), (val), __ATOMIC_SEQ_CST)
-#else /* else of defined(CLANG_GCC_HAS_ATOMIC_BUILTIN) */
+#else /* else of BH_ATOMIC_32_IS_ATOMIC != 0 */
+
 #define BH_ATOMIC_32_LOAD(v) (v)
 #define BH_ATOMIC_32_STORE(v, val) (v) = val
 #define BH_ATOMIC_32_FETCH_OR(v, val) nonatomic_32_fetch_or(&(v), val)
@@ -89,13 +123,6 @@ typedef uint16 bh_atomic_16_t;
 #define BH_ATOMIC_32_FETCH_ADD(v, val) nonatomic_32_fetch_add(&(v), val)
 #define BH_ATOMIC_32_FETCH_SUB(v, val) nonatomic_32_fetch_sub(&(v), val)
 
-#define BH_ATOMIC_16_LOAD(v) (v)
-#define BH_ATOMIC_16_STORE(v) (v) = val
-#define BH_ATOMIC_16_FETCH_OR(v, val) nonatomic_16_fetch_or(&(v), val)
-#define BH_ATOMIC_16_FETCH_AND(v, val) nonatomic_16_fetch_and(&(v), val)
-#define BH_ATOMIC_16_FETCH_ADD(v, val) nonatomic_16_fetch_add(&(v), val)
-#define BH_ATOMIC_16_FETCH_SUB(v, val) nonatomic_16_fetch_sub(&(v), val)
-
 static inline uint32
 nonatomic_32_fetch_or(bh_atomic_32_t *p, uint32 val)
 {
@@ -128,6 +155,31 @@ nonatomic_32_fetch_sub(bh_atomic_32_t *p, uint32 val)
     return old;
 }
 
+#endif
+
+#if BH_ATOMIC_16_IS_ATOMIC != 0
+
+#define BH_ATOMIC_16_IS_ATOMIC 1
+#define BH_ATOMIC_16_LOAD(v) __atomic_load_n(&(v), __ATOMIC_SEQ_CST)
+#define BH_ATOMIC_16_STORE(v, val) __atomic_store_n(&(v), val, __ATOMIC_SEQ_CST)
+#define BH_ATOMIC_16_FETCH_OR(v, val) \
+    __atomic_fetch_or(&(v), (val), __ATOMIC_SEQ_CST)
+#define BH_ATOMIC_16_FETCH_AND(v, val) \
+    __atomic_fetch_and(&(v), (val), __ATOMIC_SEQ_CST)
+#define BH_ATOMIC_16_FETCH_ADD(v, val) \
+    __atomic_fetch_add(&(v), (val), __ATOMIC_SEQ_CST)
+#define BH_ATOMIC_16_FETCH_SUB(v, val) \
+    __atomic_fetch_sub(&(v), (val), __ATOMIC_SEQ_CST)
+
+#else /* else of BH_ATOMIC_16_IS_ATOMIC != 0 */
+
+#define BH_ATOMIC_16_LOAD(v) (v)
+#define BH_ATOMIC_16_STORE(v) (v) = val
+#define BH_ATOMIC_16_FETCH_OR(v, val) nonatomic_16_fetch_or(&(v), val)
+#define BH_ATOMIC_16_FETCH_AND(v, val) nonatomic_16_fetch_and(&(v), val)
+#define BH_ATOMIC_16_FETCH_ADD(v, val) nonatomic_16_fetch_add(&(v), val)
+#define BH_ATOMIC_16_FETCH_SUB(v, val) nonatomic_16_fetch_sub(&(v), val)
+
 static inline uint16
 nonatomic_16_fetch_or(bh_atomic_16_t *p, uint16 val)
 {
@@ -160,20 +212,6 @@ nonatomic_16_fetch_sub(bh_atomic_16_t *p, uint16 val)
     return old;
 }
 
-/* The flag can be defined by the user if the platform
-   supports atomic access to uint32 aligned memory. */
-#ifdef WASM_UINT32_IS_ATOMIC
-#define BH_ATOMIC_32_IS_ATOMIC 1
-#else /* else of WASM_UINT32_IS_ATOMIC */
-#define BH_ATOMIC_32_IS_ATOMIC 0
-#endif /* WASM_UINT32_IS_ATOMIC */
-
-#ifdef WASM_UINT16_IS_ATOMIC
-#define BH_ATOMIC_16_IS_ATOMIC 1
-#else /* else of WASM_UINT16_IS_ATOMIC */
-#define BH_ATOMIC_16_IS_ATOMIC 0
-#endif /* WASM_UINT16_IS_ATOMIC */
-
 #endif
 
 #ifdef __cplusplus