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[release/6.0-vs4mac] Fix the MacOS remote unwinder for VS4Mac #63758

Merged
merged 2 commits into from
Jan 13, 2022
Merged

[release/6.0-vs4mac] Fix the MacOS remote unwinder for VS4Mac #63758

merged 2 commits into from
Jan 13, 2022

Commits on Jan 13, 2022

  1. Fix the MacOS remote unwinder for VS4Mac 

    The wrong module was being passed to the remote unwinder because the load bias for shared modules
was being calculated incorrectly.

Issue: #63309
    @mikem8361
    mikem8361 authored and github-actions committed Jan 13, 2022
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  2. Fix native frame unwind in syscall on arm64 for VS4Mac crash report 

    From PR in main: #63598

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, #16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, #32]
   3663c:       fd 83 00 91     add     x29, sp, #32
...
   367ac:       e9 01 80 52     mov     w9, #15
   367b0:       7f 3e 02 71     cmp     w19, #143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, #1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.
    @mikem8361
    mikem8361 authored and github-actions committed Jan 13, 2022
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