[release/6.0-vs4mac] Fix the MacOS remote unwinder for VS4Mac #63758
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The wrong module was being passed to the remote unwinder because the load bias for shared modules was being calculated incorrectly. Issue: #63309
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.
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Tagging subscribers to this area: @tommcdon Issue DetailsBackport of #63405 to release/6.0-vs4mac /cc @safern @mikem8361 Customer ImpactTestingRisk
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FYI: @kdubau |
mikem8361
approved these changes
Jan 13, 2022
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Merging as we exercised CI on release/6.0 and this branch was forked from there; and that'd speed up getting an official build out. |
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Backport of #63405 to release/6.0-vs4mac
/cc @safern @mikem8361
Customer Impact
Testing
Risk