[WIP] pass strings between host and wasm

.devcontainer/Dockerfile

@@ -5,7 +5,15 @@ ENV TZ=Asian/Shanghai
 
 RUN apt-get update \
   && apt-get upgrade -y \
-  && apt-get install --no-install-recommends -y cmake
+  && apt-get install --no-install-recommends -y clang llvm cmake
 
-# Fix "Unable to find libclang" issue
-RUN apt-get install --no-install-recommends -y clang-11
+#
+# wasm-tools
+ARG WASM_TOOLS_VER=1.205.0
+
+WORKDIR /opt
+RUN wget https://github.com/bytecodealliance/wasm-tools/releases/download/v${WASM_TOOLS_VER}/wasm-tools-${WASM_TOOLS_VER}-x86_64-linux.tar.gz
+RUN tar -xvf wasm-tools-${WASM_TOOLS_VER}-x86_64-linux.tar.gz \
+  && mv wasm-tools-${WASM_TOOLS_VER}-x86_64-linux wasm-tools \
+  && rm wasm-tools-${WASM_TOOLS_VER}-x86_64-linux.tar.gz \
+  && ln -s /opt/wasm-tools/wasm-tools /usr/local/bin/wasm-tools

.devcontainer/devcontainer.json

@@ -23,6 +23,8 @@
   // Configure tool-specific properties.
   "customizations": {
     "settings": {
+      "editor.formatOnSave": true,
+      "editor.formatOnType": true,
       "lldb.executable": "/usr/bin/lldb",
       "terminal.integrated.shell.linux": "/bin/bash"
     },

.devcontainer/finalize.sh

@@ -4,14 +4,16 @@ printf "Running 'postCreateCommand' Script\n"
 printf "Installing Rust Targets\n"
 rustup update stable --no-self-update
 rustup default stable
-rustup target add wasm32-unknown-unknown
+#rustup target add wasm32-unknown-unknown
 rustup target add wasm32-wasi
 rustup component add clippy
+rustup component add rustfmt
 
 cargo install cargo-readme
+cargo install rustfilt
 
 # Install Python stuff
-printf "Installing Python Dependencies"
+printf "Installing Python Dependencies\n"
 
 # Install NPM dependencies
-printf "Installing NPM Dependencies"
+printf "Installing NPM Dependencies\n"

Cargo.toml

@@ -5,8 +5,9 @@
 members = ["crates/wamr-sys"]
 exclude = [
     "examples/wasi-hello",
-    "resources/test/gcd",
     "resources/test/add-extra",
+    "resources/test/gcd",
+    "resources/test/string-concat",
     ".devcontainer",
     ".github",
 ]

resources/test/string-concat/.cargo/config.toml

@@ -0,0 +1,8 @@
+# Copyright (C) 2019 Intel Corporation. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+[target.wasm32-wasi]
+rustflags = [
+  "-C", "link-arg=--export=malloc",
+  "-C", "link-arg=--export=free",
+]

resources/test/string-concat/Cargo.toml

@@ -0,0 +1,12 @@
+# Copyright (C) 2019 Intel Corporation. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+[package]
+name = "string_concat"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rustfilt = "0.2.1"

resources/test/string-concat/src/main.rs

@@ -0,0 +1,43 @@
+use std::string::String;
+use std::alloc::{alloc, dealloc, Layout};
+
+#[no_mangle]
+#[export_name = "my_malloc"]
+pub unsafe fn my_alloc(size: usize) -> *mut u8 {
+    let align = std::mem::align_of::<usize>();
+    let layout = Layout::from_size_align_unchecked(size, align);
+    alloc(layout)
+}
+
+#[no_mangle]
+#[export_name = "my_free"]
+pub unsafe fn my_dealloc(ptr: *mut u8, size: usize) {
+    let align = std::mem::align_of::<usize>();
+    let layout = Layout::from_size_align_unchecked(size, align);
+    dealloc(ptr, layout);
+}
+
+#[no_mangle]
+#[export_name = "my_strcat"]
+pub fn my_strcat(s1: &str, s2: &str) -> String {
+    println!("-=-|> s1: {}, s2: {}", s1, s2);
+
+    let mut result = String::with_capacity(s1.len() + s2.len());
+    let ret_ref = &result;
+    println!("  --> the address of result: {:p}", ret_ref as *const String);
+
+    result.push_str(s1);
+    result.push_str(s2);
+    println!("  --> result: {result}");
+
+    result
+}
+
+fn main() {
+    let result = my_strcat("hello", "world");
+    println!("-> {}", result);
+    let result = my_strcat(&result, "from, xxx,");
+    println!("-> {}", result);
+    let result = my_strcat(&result, "main function");
+    println!("-> {}", result);
+}