[all-commits] [llvm/llvm-project] 8a27ef: [lldb] Add frame recognizer for __builtin_verbose_...

[Michael Buch via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8a27ef676e3c607daede048e5021db18a970aa71
      https://github.com/llvm/llvm-project/commit/8a27ef676e3c607daede048e5021db18a970aa71
  Author: Michael Buch <michaelbuch12 at gmail.com>
  Date:   2024-07-16 (Tue, 16 Jul 2024)

  Changed paths:
    A lldb/include/lldb/Target/VerboseTrapFrameRecognizer.h
    M lldb/source/Target/CMakeLists.txt
    M lldb/source/Target/Process.cpp
    A lldb/source/Target/VerboseTrapFrameRecognizer.cpp
    A lldb/test/Shell/Recognizer/Inputs/verbose_trap.cpp
    A lldb/test/Shell/Recognizer/verbose_trap.test

  Log Message:
  -----------
  [lldb] Add frame recognizer for __builtin_verbose_trap (#80368)

This patch adds a frame recognizer for Clang's
`__builtin_verbose_trap`, which behaves like a
`__builtin_trap`, but emits a failure-reason string into debug-info in
order for debuggers to display
it to a user.

The frame recognizer triggers when we encounter
a frame with a function name that begins with
`__clang_trap_msg`, which is the magic prefix
Clang emits into debug-info for verbose traps.
Once such frame is encountered we display the
frame function name as the `Stop Reason` and display that frame to the
user.

Example output:
```
(lldb) run
warning: a.out was compiled with optimization - stepping may behave oddly; variables may not be available.
Process 35942 launched: 'a.out' (arm64)
Process 35942 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = Misc.: Function is not implemented
    frame #1: 0x0000000100003fa4 a.out`main [inlined] Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
   1    struct Dummy {
   2      void func() {
-> 3        __builtin_verbose_trap("Misc.", "Function is not implemented");
   4      }
   5    };
   6
   7    int main() {
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = Misc.: Function is not implemented
    frame #0: 0x0000000100003fa4 a.out`main [inlined] __clang_trap_msg$Misc.$Function is not implemented$ at verbose_trap.cpp:0 [opt]
  * frame #1: 0x0000000100003fa4 a.out`main [inlined] Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
    frame #2: 0x0000000100003fa4 a.out`main at verbose_trap.cpp:8:13 [opt]
    frame #3: 0x0000000189d518b4 dyld`start + 1988
```



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