wasm-micro-runtime/doc/source_debugging.md

WAMR source debugging

WAMR supports source level debugging based on DWARF (normally used in C/C++/Rust), source map (normally used in AssemblyScript) is not supported.

Build wasm application with debug information

To debug your application, you need to compile them with debug information. You can use -g option when compiling the source code if you are using wasi-sdk (also work for emcc and rustc):

/opt/wasi-sdk/bin/clang -g test.c -o test.wasm

Then you will get test.wasm which is a WebAssembly module with embedded DWARF sections. Further, you can use llvm-dwarfdump to check if the generated wasm file contains DWARF information:

llvm-dwarfdump-12 test.wasm

Debugging with interpreter

1. Install dependent libraries

apt update && apt install cmake make g++ libxml2-dev -y

2. Build iwasm with source debugging feature

cd ${WAMR_ROOT}/product-mini/platforms/linux
mkdir build && cd build
cmake .. -DWAMR_BUILD_DEBUG_INTERP=1
make

3. Execute iwasm with debug engine enabled

iwasm -g=127.0.0.1:1234 test.wasm
# Use port = 0 to allow a random assigned debug port

4. Build customized lldb (assume you have already cloned llvm)

cd ${WAMR_ROOT}/core/deps/llvm
git apply ../../../build-scripts/lldb-wasm.patch
mkdir build-lldb && cd build-lldb
cmake -DCMAKE_BUILD_TYPE:STRING="Release" -DLLVM_ENABLE_PROJECTS="clang;lldb" -DLLVM_TARGETS_TO_BUILD:STRING="X86;WebAssembly" -DLLVM_ENABLE_LIBXML2:BOOL=ON ../llvm
make -j $(nproc)

5. Launch customized lldb and connect to iwasm

lldb
(lldb) process connect -p wasm connect://127.0.0.1:1234

Then you can use lldb commands to debug your applications. Please refer to lldb document for command usage.

Known issue: step over on some function may be treated as step in, it will be fixed later.

Debugging with AoT

Note: AoT debugging is experimental and only a few debugging capabilities are supported.

1. Build lldb (assume you have already built llvm)

cd ${WAMR_ROOT}/core/deps/llvm/build
cmake . -DLLVM_ENABLE_PROJECTS="clang;lldb"
make -j $(nproc)

2. Build wamrc with debugging feature

cd ${WAMR_ROOT}/wamr-compiler
mkdir build && cd build
cmake .. -DWAMR_BUILD_DEBUG_AOT=1
make -j $(nproc)

3. Build iwasm with debugging feature

cd ${WAMR_ROOT}/product-mini/platforms/linux
mkdir build && cd build
cmake .. -DWAMR_BUILD_DEBUG_AOT=1
make

4. Compile wasm module to AoT module

wamrc -o test.aot test.wasm

5. Execute iwasm using lldb

lldb-12 iwasm -- test.aot

Then you can use lldb commands to debug both wamr runtime and your wasm application in current terminal