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author | Adrian Prantl <aprantl@apple.com> | 2024-08-20 16:01:22 -0700 |
---|---|---|
committer | GitHub <noreply@github.com> | 2024-08-20 16:01:22 -0700 |
commit | f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9 (patch) | |
tree | c38a79f19b1eef07a0b315cc067035d380a83c80 /lldb/source/Commands/CommandObjectThread.cpp | |
parent | 1e9d0028d35ae69263aa848b4cb02245f442eb5c (diff) | |
download | llvm-f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9.zip llvm-f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9.tar.gz llvm-f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9.tar.bz2 |
[lldb] Extend frame recognizers to hide frames from backtraces (#104523)
Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.
This does not affect the numbering of frames, so `f <N>` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.
My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.
rdar://126629381
Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).
before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
* frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
frame #4: 0x00000001000026bc a.out`std::__1::__function::__func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
frame #5: 0x0000000100003c38 a.out`std::__1::__function::__value_func<int (int, int)>::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
frame #8: 0x0000000183cdf154 dyld`start + 2476
(lldb)
```
after
```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
* frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
frame #8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```
Diffstat (limited to 'lldb/source/Commands/CommandObjectThread.cpp')
-rw-r--r-- | lldb/source/Commands/CommandObjectThread.cpp | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp index 605f872..6a89c16 100644 --- a/lldb/source/Commands/CommandObjectThread.cpp +++ b/lldb/source/Commands/CommandObjectThread.cpp @@ -89,6 +89,9 @@ public: "invalid boolean value for option '%c': %s", short_option, option_arg.data()); } break; + case 'u': + m_filtered_backtrace = false; + break; default: llvm_unreachable("Unimplemented option"); } @@ -99,6 +102,7 @@ public: m_count = UINT32_MAX; m_start = 0; m_extended_backtrace = false; + m_filtered_backtrace = true; } llvm::ArrayRef<OptionDefinition> GetDefinitions() override { @@ -109,6 +113,7 @@ public: uint32_t m_count; uint32_t m_start; bool m_extended_backtrace; + bool m_filtered_backtrace; }; CommandObjectThreadBacktrace(CommandInterpreter &interpreter) @@ -121,7 +126,10 @@ public: "call stacks.\n" "Use 'settings set frame-format' to customize the printing of " "frames in the backtrace and 'settings set thread-format' to " - "customize the thread header.", + "customize the thread header.\n" + "Customizable frame recognizers may filter out less interesting " + "frames, which results in gaps in the numbering. " + "Use '-u' to see all frames.", nullptr, eCommandRequiresProcess | eCommandRequiresThread | eCommandTryTargetAPILock | eCommandProcessMustBeLaunched | @@ -199,7 +207,8 @@ protected: strm.PutChar('\n'); if (ext_thread_sp->GetStatus(strm, m_options.m_start, m_options.m_count, - num_frames_with_source, stop_format)) { + num_frames_with_source, stop_format, + !m_options.m_filtered_backtrace)) { DoExtendedBacktrace(ext_thread_sp.get(), result); } } @@ -228,7 +237,8 @@ protected: const uint32_t num_frames_with_source = 0; const bool stop_format = true; if (!thread->GetStatus(strm, m_options.m_start, m_options.m_count, - num_frames_with_source, stop_format, only_stacks)) { + num_frames_with_source, stop_format, + !m_options.m_filtered_backtrace, only_stacks)) { result.AppendErrorWithFormat( "error displaying backtrace for thread: \"0x%4.4x\"\n", thread->GetIndexID()); @@ -1392,7 +1402,8 @@ public: const uint32_t num_frames_with_source = 0; const bool stop_format = false; exception_thread_sp->GetStatus(strm, 0, UINT32_MAX, - num_frames_with_source, stop_format); + num_frames_with_source, stop_format, + /*filtered*/ false); } return true; |