Commits on Oct 11, 2023

1. Rewrite msvc backtrace support to be much faster on 64-bit platforms …

   Currently, capturing the stack backtrace is done on Windows by calling
   into `dbghelp!StackWalkEx` (or `dbghelp!StackWalk64` if the version of
   `dbghelp` we loaded is too old to contain that function). This is very
   convenient since `StackWalkEx` handles everything for us but there are
   two issues with doing so:
   
   1. `dbghelp` is not safe to use from multiple threads at the same time
      so all calls into it must be serialized.
   2. `StackWalkEx` returns inlined frames as if they were regular stack
      frames which requires loading debug info just to walk the stack. As a
      result, simply capturing a backtrace without resolving it is much
      more expensive on Windows than *nix.
   
   This change rewrites our Windows support to call `RtlVirtualUnwind`
   instead on platforms which support this API (`x86_64` and `aarch64`).
   This API walks the actual (ie, not inlined) stack frames so it does not
   require loading any debug info and is significantly faster. For
   platforms that do not support `RtlVirtualUnwind` (ie, `i686`), we fall
   back to the current implementation which calls into `dbghelp`.
   
   To recover the inlined frame information when we are asked to resolve
   symbols, we use `SymAddrIncludeInlineTrace` to load debug info and
   detect inlined frames and then `SymQueryInlineTrace` to get the
   appropriate inline context to resolve them.
   
   The result is significant performance improvements to backtrace capture
   and symbolizing on Windows!
   
   Before:
   
   ```
   > cargo +nightly bench
        Running benches\benchmarks.rs
   
   running 6 tests
   test new                                 ... bench:     658,652 ns/iter (+/- 30,741)
   test new_unresolved                      ... bench:     343,240 ns/iter (+/- 13,108)
   test new_unresolved_and_resolve_separate ... bench:     648,890 ns/iter (+/- 31,651)
   test trace                               ... bench:     304,815 ns/iter (+/- 19,633)
   test trace_and_resolve_callback          ... bench:     463,645 ns/iter (+/- 12,893)
   test trace_and_resolve_separate          ... bench:     474,290 ns/iter (+/- 73,858)
   
   test result: ok. 0 passed; 0 failed; 0 ignored; 6 measured; 0 filtered out; finished in 8.26s
   ```
   
   After:
   
   ```
   > cargo +nightly bench
        Running benches\benchmarks.rs
   
   running 6 tests
   test new                                 ... bench:     495,468 ns/iter (+/- 31,215)
   test new_unresolved                      ... bench:       1,241 ns/iter (+/- 251)
   test new_unresolved_and_resolve_separate ... bench:     436,730 ns/iter (+/- 32,482)
   test trace                               ... bench:         850 ns/iter (+/- 162)
   test trace_and_resolve_callback          ... bench:     410,790 ns/iter (+/- 19,424)
   test trace_and_resolve_separate          ... bench:     408,090 ns/iter (+/- 29,324)
   
   test result: ok. 0 passed; 0 failed; 0 ignored; 6 measured; 0 filtered out; finished in 7.02s
   ```
   
   The changes to the symbolize step also allow us to report inlined frames
   when resolving from just an instruction address which was not previously
   possible.

   

   wesleywiser committed Oct 11, 2023
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2. Update cfg for x86/arm and fix image param

   

   wesleywiser committed Oct 11, 2023
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