add realloc wrapper, fix pthread_join overwrite issue (#605)

core/iwasm/aot/aot_runtime.c

@@ -1553,6 +1553,43 @@ aot_module_malloc(AOTModuleInstance *module_inst, uint32 size,
     return (uint32)(addr - (uint8*)memory_inst->memory_data.ptr);
 }
 
+uint32
+aot_module_realloc(AOTModuleInstance *module_inst, uint32 ptr,
+                   uint32 size, void **p_native_addr)
+{
+    AOTMemoryInstance *memory_inst = aot_get_default_memory(module_inst);
+    uint8 *addr = NULL;
+
+    if (!memory_inst) {
+        aot_set_exception(module_inst, "uninitialized memory");
+        return 0;
+    }
+
+    if (memory_inst->heap_handle.ptr) {
+        addr =
+            mem_allocator_realloc(memory_inst->heap_handle.ptr,
+                                  (uint8*)memory_inst->memory_data.ptr + ptr,
+                                  size);
+    }
+
+    /* Only support realloc in WAMR's app heap */
+
+    if (!addr) {
+        if (memory_inst->heap_handle.ptr
+            && mem_allocator_is_heap_corrupted(memory_inst->heap_handle.ptr)) {
+            aot_set_exception(module_inst, "app heap corrupted");
+        }
+        else {
+            aot_set_exception(module_inst, "out of memory");
+        }
+        return 0;
+    }
+
+    if (p_native_addr)
+        *p_native_addr = addr;
+    return (uint32)(addr - (uint8*)memory_inst->memory_data.ptr);
+}
+
 void
 aot_module_free(AOTModuleInstance *module_inst, uint32 ptr)
 {

core/iwasm/aot/aot_runtime.h

@@ -498,6 +498,10 @@ uint32
 aot_module_malloc(AOTModuleInstance *module_inst, uint32 size,
                   void **p_native_addr);
 
+uint32
+aot_module_realloc(AOTModuleInstance *module_inst, uint32 ptr,
+                   uint32 size, void **p_native_addr);
+
 void
 aot_module_free(AOTModuleInstance *module_inst, uint32 ptr);
 

core/iwasm/common/wasm_runtime_common.c

@@ -1378,6 +1378,23 @@ wasm_runtime_module_malloc(WASMModuleInstanceCommon *module_inst, uint32 size,
     return 0;
 }
 
+uint32
+wasm_runtime_module_realloc(WASMModuleInstanceCommon *module_inst, uint32 ptr,
+                            uint32 size, void **p_native_addr)
+{
+#if WASM_ENABLE_INTERP != 0
+    if (module_inst->module_type == Wasm_Module_Bytecode)
+        return wasm_module_realloc((WASMModuleInstance*)module_inst, ptr,
+                                   size, p_native_addr);
+#endif
+#if WASM_ENABLE_AOT != 0
+    if (module_inst->module_type == Wasm_Module_AoT)
+        return aot_module_realloc((AOTModuleInstance*)module_inst, ptr,
+                                  size, p_native_addr);
+#endif
+    return 0;
+}
+
 void
 wasm_runtime_module_free(WASMModuleInstanceCommon *module_inst, uint32 ptr)
 {

core/iwasm/interpreter/wasm_runtime.c

@@ -1741,6 +1741,41 @@ wasm_module_malloc(WASMModuleInstance *module_inst, uint32 size,
     return (uint32)(addr - memory->memory_data);
 }
 
+uint32
+wasm_module_realloc(WASMModuleInstance *module_inst, uint32 ptr, uint32 size,
+                    void **p_native_addr)
+{
+    WASMMemoryInstance *memory = module_inst->default_memory;
+    uint8 *addr = NULL;
+
+    if (!memory) {
+        wasm_set_exception(module_inst, "uninitialized memory");
+        return 0;
+    }
+
+    if (memory->heap_handle) {
+        addr = mem_allocator_realloc(memory->heap_handle,
+                                     memory->memory_data + ptr, size);
+    }
+
+    /* Only support realloc in WAMR's app heap */
+
+    if (!addr) {
+        if (memory->heap_handle
+            && mem_allocator_is_heap_corrupted(memory->heap_handle)) {
+            wasm_set_exception(module_inst, "app heap corrupted");
+        }
+        else {
+            wasm_set_exception(module_inst, "out of memory");
+        }
+        return 0;
+    }
+    if (p_native_addr)
+        *p_native_addr = addr;
+
+    return (uint32)(addr - memory->memory_data);
+}
+
 void
 wasm_module_free(WASMModuleInstance *module_inst, uint32 ptr)
 {

core/iwasm/interpreter/wasm_runtime.h

@@ -328,6 +328,10 @@ uint32
 wasm_module_malloc(WASMModuleInstance *module_inst, uint32 size,
                    void **p_native_addr);
 
+uint32
+wasm_module_realloc(WASMModuleInstance *module_inst, uint32 ptr, uint32 size,
+                    void **p_native_addr);
+
 void
 wasm_module_free(WASMModuleInstance *module_inst, uint32 ptr);
 

core/iwasm/libraries/lib-pthread/lib_pthread_wrapper.c

@@ -648,7 +648,7 @@ pthread_join_wrapper(wasm_exec_env_t exec_env, uint32 thread,
     }
 
     if (retval_offset != 0)
-        *retval = (void*)ret;
+        *(uint32*)retval = (uint32)(uintptr_t)ret;
 
     return join_ret;
 }

core/iwasm/libraries/libc-builtin/libc_builtin_wrapper.c

@@ -28,6 +28,10 @@ wasm_runtime_get_llvm_stack(wasm_module_inst_t module);
 void
 wasm_runtime_set_llvm_stack(wasm_module_inst_t module, uint32 llvm_stack);
 
+uint32
+wasm_runtime_module_realloc(wasm_module_inst_t module, uint32 ptr,
+                            uint32 size, void **p_native_addr);
+
 #define get_module_inst(exec_env) \
     wasm_runtime_get_module_inst(exec_env)
 
@@ -704,6 +708,14 @@ calloc_wrapper(wasm_exec_env_t exec_env, uint32 nmemb, uint32 size)
     return ret_offset;
 }
 
+static uint32
+realloc_wrapper(wasm_exec_env_t exec_env, uint32 ptr, uint32 new_size)
+{
+    wasm_module_inst_t module_inst = get_module_inst(exec_env);
+
+    return wasm_runtime_module_realloc(module_inst, ptr, new_size, NULL);
+}
+
 static void
 free_wrapper(wasm_exec_env_t exec_env, void *ptr)
 {
@@ -1092,6 +1104,7 @@ static NativeSymbol native_symbols_libc_builtin[] = {
     REG_NATIVE_FUNC(strncmp, "(**~)i"),
     REG_NATIVE_FUNC(strncpy, "(**~)i"),
     REG_NATIVE_FUNC(malloc, "(i)i"),
+    REG_NATIVE_FUNC(realloc, "(ii)i"),
     REG_NATIVE_FUNC(calloc, "(ii)i"),
     REG_NATIVE_FUNC(strdup, "($)i"),
     /* clang may introduce __strdup */

doc/pthread_library.md

@@ -57,7 +57,7 @@ To build this C program into WebAssembly app with libc-builtin, you can use this
 
 You can also build this program with WASI, but we need to make some changes to wasi-sysroot:
 
-1. disable malloc/free of wasi if the wasi-sdk version is smaller than wasi-sdk-12.0 (not include 12.0), as they don't support shared memory:
+1. disable malloc/free of wasi, as they are not atomic operations:
     ``` bash
     /opt/wasi-sdk/bin/llvm-ar -d /opt/wasi-sdk/share/wasi-sysroot/lib/wasm32-wasi/libc.a dlmalloc.o
     ```

wamr-sdk/app/libc-builtin-sysroot/share/defined-symbols.txt

@@ -40,6 +40,7 @@ strncmp
 strncpy
 malloc
 calloc
+realloc
 strdup
 free
 atoi