Update build scripts and documents of workload samples for wasi-sdk-12.0 (#484)

Update the build scripts of sample workloads (meshoptimizer/bwa/wasm-av1) to use the wasi-sdk-12.0 firstly to build the workload and discard clang-11, as wasi-sdk-12 supports wasi, simd and pthread better. And update the related documents.
Also modify wasm mini loader to sync up with the change of wasm normal loader.

Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>

samples/workload/meshoptimizer/CMakeLists.txt

@@ -5,6 +5,38 @@ cmake_minimum_required (VERSION 3.0)
 
 project(bench-meshoptimizer)
 
+################  WASI-SDK ################
+find_path(WASI_SDK_HOME
+  NAMES wasi-sdk
+  PATHS /opt/
+  REQUIRED
+)
+
+if (NOT WASI_SDK_HOME)
+  message(FATAL_ERROR
+    "can not find wasi-sdk. "
+    "please download it from "
+    "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-12/wasi-sdk-12.0-linux.tar.gz "
+    "and install it under /opt/wasi-sdk"
+  )
+endif()
+
+#
+# check clang version
+execute_process(COMMAND
+  ${WASI_SDK_HOME}/wasi-sdk/bin/clang --version
+  OUTPUT_VARIABLE clang_full_version_string
+)
+string(REGEX REPLACE ".*clang version ([0-9]+\\.[0-9]+).*" "\\1"
+  CLANG_VERSION_STRING ${clang_full_version_string}
+)
+message("cur clang version is ${CLANG_VERSION_STRING}")
+if(CLANG_VERSION_STRING VERSION_LESS 11.0)
+  message(FATAL_ERROR
+    "please install latest wai-sdk to get a clang-11 at least"
+  )
+endif()
+
 ################  BINARYEN ################
 find_program(WASM_OPT
     NAMES wasm-opt
@@ -33,7 +65,10 @@ ExternalProject_Add(codecbench
   UPDATE_COMMAND git clean -fd && git checkout -- *
                    && ${CMAKE_COMMAND} -E echo "Applying patch"
                    && git apply ${CMAKE_CURRENT_SOURCE_DIR}/codecbench.patch
-  CONFIGURE_COMMAND ${CMAKE_COMMAND} -DCMAKE_TOOLCHAIN_FILE=${CMAKE_CURRENT_SOURCE_DIR}/../cmake/toolchain.cmake ${CMAKE_CURRENT_SOURCE_DIR}/meshoptimizer
+  CONFIGURE_COMMAND ${CMAKE_COMMAND}
+                         -DWASI_SDK_PREFIX=${WASI_SDK_HOME}/wasi-sdk
+                         -DCMAKE_TOOLCHAIN_FILE=${WASI_SDK_HOME}/wasi-sdk/share/cmake/wasi-sdk.cmake
+                         ${CMAKE_CURRENT_SOURCE_DIR}/meshoptimizer
   BUILD_COMMAND  make codecbench.opt
   INSTALL_COMMAND ${CMAKE_COMMAND} -E copy ./codecbench.opt.wasm ${CMAKE_CURRENT_SOURCE_DIR}/build/codecbench.wasm
 )

samples/workload/meshoptimizer/README.md

@@ -8,7 +8,7 @@ WebAssembly with simd support and run it with iwasm.
 
 please refer to [installation instructions](../README.md).
 
-## Build with clang-11 and wasi-sdk
+## Build with wasi-sdk
 
 ``` shell
 $ mkdir build && cd build
@@ -18,15 +18,15 @@ $ make
 $ ls codecbench.wasm
 ```
 
-## Or build with EMCC
+## Or build with EMSDK
 
-EMCC is another toolchain to compile C code to WASM. In this case, will have
-a higher performance with EMCC.
+EMSDK is another toolchain to compile C/C++ code to WASM. In this case, the output wasm file
+might have a higher performance than the file generated by wasi-sdk.
 
 ``` shell
 $ git clone https://github.com/zeux/meshoptimizer.git
 $ cd messoptimizer
-$ emcc tools/codecbench.cpp src/vertexcodec.cpp src/vertexfilter.cpp \
+$ em++ tools/codecbench.cpp src/vertexcodec.cpp src/vertexfilter.cpp \
        src/overdrawanalyzer.cpp src/indexgenerator.cpp src/vcacheoptimizer.cpp \
        src/clusterizer.cpp src/indexcodec.cpp src/vfetchanalyzer.cpp \
        src/spatialorder.cpp src/allocator.cpp src/vcacheanalyzer.cpp \
@@ -51,9 +51,7 @@ $ make
 Then compile wasm file to aot file and run:
 
 ``` shell
-$ cd <wamr dir>/wamr-compiler/build
-$ ./wamrc --enable-simd -o codecbench.aot codecbench.wasm
-$ cd <wamr dir>/product-mini/platforms/linux/
-$ ./iwasm codecbench.aot
+$ <wamr dir>/wamr-compiler/build/wamrc --enable-simd -o codecbench.aot codecbench.wasm
+$ <wamr dir>/product-mini/platforms/linux/build/iwasm codecbench.aot
 ```
 

samples/workload/meshoptimizer/codecbench.patch

@@ -1,8 +1,8 @@
 diff --git a/CMakeLists.txt b/CMakeLists.txt
-index eccc49e..dac126c 100644
+index ffdb4da..536a5c8 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
-@@ -127,3 +127,42 @@ install(FILES
+@@ -127,3 +127,43 @@ install(FILES
      ${CMAKE_CURRENT_BINARY_DIR}/meshoptimizerConfig.cmake
      ${CMAKE_CURRENT_BINARY_DIR}/meshoptimizerConfigVersion.cmake
      DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/meshoptimizer)
@@ -16,6 +16,7 @@ index eccc49e..dac126c 100644
 +
 +target_compile_options(codecbench
 +  PUBLIC
++    -O3 -msimd128
 +    -std=c++11
 +    -Wno-unused-function
 +    -Wno-unused-variable