Fix some compile warnings and update document (#670)

And implement clock_gettime wrapper for libc-built.

core/app-mgr/app-manager/module_wasm_app.c

@@ -1674,7 +1674,7 @@ wasm_set_wasi_root_dir(const char *root_dir)
     if (!(path = realpath(root_dir, resolved_path)))
         return false;
 
-    strncpy(wasi_root_dir, path, sizeof(wasi_root_dir));
+    snprintf(wasi_root_dir, sizeof(wasi_root_dir), "%s", path);
     return true;
 }
 

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

@@ -1068,6 +1068,28 @@ __cxa_throw_wrapper(wasm_exec_env_t exec_env,
     wasm_runtime_set_exception(module_inst, buf);
 }
 
+struct timespec_app {
+    int64 tv_sec;
+    int32 tv_nsec;
+};
+
+static uint32
+clock_gettime_wrapper(wasm_exec_env_t exec_env,
+                      uint32 clk_id, struct timespec_app *ts_app)
+{
+    wasm_module_inst_t module_inst = get_module_inst(exec_env);
+    uint64 time;
+
+    if (!validate_native_addr(ts_app, sizeof(struct timespec_app)))
+        return (uint32)-1;
+
+    time = os_time_get_boot_microsecond();
+    ts_app->tv_sec = time / 1000000;
+    ts_app->tv_nsec = (time % 1000000) * 1000;
+
+    return (uint32)0;
+}
+
 #if WASM_ENABLE_SPEC_TEST != 0
 static void
 print_wrapper(wasm_exec_env_t exec_env)
@@ -1167,6 +1189,7 @@ static NativeSymbol native_symbols_libc_builtin[] = {
     REG_NATIVE_FUNC(__cxa_allocate_exception, "(i)i"),
     REG_NATIVE_FUNC(__cxa_begin_catch, "(*)"),
     REG_NATIVE_FUNC(__cxa_throw, "(**i)"),
+    REG_NATIVE_FUNC(clock_gettime, "(i*)i"),
 };
 
 #if WASM_ENABLE_SPEC_TEST != 0

doc/build_wamr.md

@@ -20,7 +20,8 @@ The script `runtime_lib.cmake` defines a number of variables for configuring the
 - **WAMR_BUILD_PLATFORM**:  set the target platform. It can be set to any platform name (folder name) under folder [core/shared/platform](../core/shared/platform).
 
 - **WAMR_BUILD_TARGET**: set the target CPU architecture. Current supported targets are:  X86_64, X86_32, AARCH64, ARM, THUMB, XTENSA, RISCV64 and MIPS.
-  - For ARM and THUMB, the format is \<arch>\[\<sub-arch>]\[_VFP], where \<sub-arch> is the ARM sub-architecture and the "_VFP" suffix means using VFP coprocessor registers s0-s15 (d0-d7) for passing arguments or returning results in standard procedure-call. For AARCH64, the format is\<arch>[\<sub-arch>], VFP is enabled by default. Both \<sub-arch> and "_VFP" are optional, e.g. AARCH64, AARCH64V8, AARCHV8.1, ARMV7, ARMV7_VFP, THUMBV7, THUMBV7_VFP and so on.
+  - For ARM and THUMB, the format is \<arch>\[\<sub-arch>]\[_VFP], where \<sub-arch> is the ARM sub-architecture and the "_VFP" suffix means using VFP coprocessor registers s0-s15 (d0-d7) for passing arguments or returning results in standard procedure-call. Both \<sub-arch> and "_VFP" are optional, e.g. ARMV7, ARMV7_VFP, THUMBV7, THUMBV7_VFP and so on.
+  - For AARCH64, the format is\<arch>[\<sub-arch>], VFP is enabled by default. \<sub-arch> is optional, e.g. AARCH64, AARCH64V8, AARCH64V8.1 and so on.
   - For RISCV64, the format is \<arch\>[_abi], where "_abi" is optional, currently the supported formats are RISCV64, RISCV64_LP64D and RISCV64_LP64: RISCV64 and RISCV64_LP64D are identical, using [LP64D](https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-named-abis) as abi (LP64 with hardware floating-point calling convention for FLEN=64). And RISCV64_LP64 uses [LP64](https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-named-abis) as abi (Integer calling-convention only, and hardware floating-point calling convention is not used).
   - For RISCV32, the format is \<arch\>[_abi], where "_abi" is optional, currently the supported formats are RISCV32, RISCV32_ILP32D and RISCV32_ILP32: RISCV32 and RISCV32_ILP32D are identical, using [ILP32D](https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-named-abis) as abi (ILP32 with hardware floating-point calling convention for FLEN=64). And RISCV32_ILP32 uses [ILP32](https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-named-abis) as abi (Integer calling-convention only, and hardware floating-point calling convention is not used).
 
@@ -465,4 +466,4 @@ $ ls ../build_out/
 *build_wamr.sh* will generate *linux* compatible libraries ( libiwasm.so and
 libvmlib.a ) and an executable binary (*iwasm*) and copy *iwasm* to
 *build_out*. All original generated files are still under
-*product-mini/platforms/linux/build*.
+*product-mini/platforms/linux/build*.

product-mini/platforms/linux/CMakeLists.txt

@@ -94,12 +94,6 @@ if (COLLECT_CODE_COVERAGE EQUAL 1)
   set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fprofile-arcs -ftest-coverage")
 endif ()
 
-# UNDEFINED BEHAVIOR
-# refer to https://en.cppreference.com/w/cpp/language/ub
-if(CMAKE_BUILD_TYPE STREQUAL "Debug")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=undefined -fno-sanitize-recover")
-endif()
-
 set (WAMR_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../..)
 
 include (${WAMR_ROOT_DIR}/build-scripts/runtime_lib.cmake)
@@ -114,6 +108,10 @@ if (WAMR_BUILD_TARGET MATCHES "X86_.*" OR WAMR_BUILD_TARGET STREQUAL "AMD_64")
   if (NOT (CMAKE_C_COMPILER MATCHES ".*clang.*" OR CMAKE_C_COMPILER_ID MATCHES ".*Clang"))
     set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mindirect-branch-register")
   endif ()
+  # UNDEFINED BEHAVIOR, refer to https://en.cppreference.com/w/cpp/language/ub
+  if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=undefined -fno-sanitize-recover")
+  endif()
 endif ()
 
 # The following flags are to enhance security, but it may impact performance,

samples/littlevgl/vgl-wasm-runtime/src/platform/zephyr/iwasm_main.c

@@ -27,7 +27,8 @@ extern int aee_host_msg_callback(void *msg, uint32_t msg_len);
 
 int uart_char_cnt = 0;
 
-static void uart_irq_callback(struct device *dev)
+static void uart_irq_callback(const struct device *dev,
+                              void *user_data)
 {
     unsigned char ch;
 
@@ -35,9 +36,10 @@ static void uart_irq_callback(struct device *dev)
         uart_char_cnt++;
         aee_host_msg_callback(&ch, 1);
     }
+    (void)user_data;
 }
 
-struct device *uart_dev = NULL;
+const struct device *uart_dev = NULL;
 
 static bool host_init()
 {