wasm-micro-runtime/doc/source_debugging_aot.md
YAMAMOTO Takashi 5edd85d055
doc: Separate source_debugging.md into two files (#2932)
The original file was confusing as it contains both of
interpreter and aot debugging information intermixed.
2023-12-27 15:51:51 +08:00

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# WAMR source debugging (AOT)
## 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 ../llvm -DLLVM_ENABLE_PROJECTS="clang;lldb" -DLLDB_INCLUDE_TESTS=OFF
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
Then you can use lldb commands to debug both wamr runtime and your wasm application in ***current terminal***.
``` bash
% lldb iwasm -- test.aot
(lldb) target create "iwasm"
Current executable set to 'iwasm' (x86_64).
(lldb) settings set -- target.run-args "test.aot"
(lldb) settings set plugin.jit-loader.gdb.enable on
(lldb) b main
Breakpoint 1: where = iwasm`main + 48 at main.c:294:11, address = 0x0000000100001020
(lldb) run
Process 27954 launched: '/tmp/bin/iwasm' (x86_64)
Process 27954 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x0000000100001020 iwasm`main(argc=2, argv=0x00007ff7bfeff678) at main.c:294:11
291 int
292 main(int argc, char *argv[])
293 {
-> 294 int32 ret = -1;
295 char *wasm_file = NULL;
296 const char *func_name = NULL;
297 uint8 *wasm_file_buf = NULL;
Target 0: (iwasm) stopped.
(lldb) c
Process 27954 resuming
1 location added to breakpoint 1
error: need to add support for DW_TAG_base_type 'void' encoded with DW_ATE = 0x0, bit_size = 0
Process 27954 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.2
frame #0: 0x00000001002980a0 JIT(0x100298004)`main(exenv=0x0000000301808200) at hello.c:6:9
3 int
4 main(void)
5 {
-> 6 printf("hello\n");
7
8 return 0;
9 }
Target 0: (iwasm) stopped.
(lldb) br l
Current breakpoints:
1: name = 'main', locations = 2, resolved = 2, hit count = 2
1.1: where = iwasm`main + 48 at main.c:294:11, address = 0x0000000100001020, resolved, hit count = 1
1.2: where = JIT(0x100298004)`main + 12 at hello.c:6:9, address = 0x00000001002980a0, resolved, hit count = 1
(lldb)
```
* In the above example,
* The first `main` function, which is in `main.c`, is the main
function of the iwasm command.
* The second `main` function, which is in `hello.c`, is the main
function of the AOT-compiled wasm module.
* WAMR AOT debugging uses the GDB JIT loader mechanism to load
the debug info of the debugee module.
On some platforms including macOS, you need to enable it explicitly.
(`settings set plugin.jit-loader.gdb.enable on`)
References:
* https://github.com/llvm/llvm-project/blob/main/llvm/docs/DebuggingJITedCode.rst
* https://sourceware.org/gdb/current/onlinedocs/gdb/JIT-Interface.html