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):
``` bash
/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:
``` bash
llvm-dwarfdump-12 test.wasm
```

## Debugging with interpreter
1. Install dependent libraries
``` bash
apt update && apt install cmake make g++ libxml2-dev -y
```

2. Build iwasm with source debugging feature
``` bash
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
``` bash
iwasm -g=127.0.0.1:1234 test.wasm
```

4. Build customized lldb (assume you have already cloned llvm)
``` bash
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
``` bash
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](https://lldb.llvm.org/use/tutorial.html) 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)
``` bash
cd ${WAMR_ROOT}/core/deps/llvm/build
cmake . -DLLVM_ENABLE_PROJECTS="clang;lldb"
make -j $(nproc)
```

2. Build wamrc with debugging feature
``` bash
cd ${WAMR_ROOT}/wamr-compiler
mkdir build && cd build
cmake .. -DWAMR_BUILD_DEBUG_AOT=1
make -j $(nproc)
```

3. Build iwasm with debugging feature
``` bash
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
``` bash
wamrc -o test.aot test.wasm
```

5. Execute iwasm using lldb
``` bash
lldb-12 iwasm -- test.aot
```

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