[PATCH] D105169: [Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default

[Hyeongyu Kim via Phabricator via cfe-commits]

hyeongyukim added a comment.

I checked the reason for failure in address sanitizer tests on the 2-stage aarch64 buildbots.
The buildbot failure was occured because the `internal_clone` function of the `compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp` file is being compiled incorrectly.
The `internal_clone` function is a simple function that calls the clone system call of Linux. Its original return value should be the PID of the newly created process, but the actual returned value is 220 (which is the `__NR_clone` value.)

The aarch64 assembly changed by this patch is as follows.

  // before
  84: d2801b88  mov x8, #0xdc                   // #0xdc(220): system call number of clone
  88: d4000001  svc #0x0                        // system call
  ...
  a4: a9434ff4  ldp x20, x19, [sp, #48]
  a8: a94257f6  ldp x22, x21, [sp, #32]
  ac: a9415ff8  ldp x24, x23, [sp, #16]
  b0: a8c467fe  ldp x30, x25, [sp], #64
  b4: d65f03c0  ret
  
  =========================
  // after
  88: d2801b88  mov x8, #0xdc                   // #0xdc(220): system call number of clone
  8c: d4000001  svc #0x0                        // system call
  ...
  a8: a9434ff4  ldp x20, x19, [sp, #48]
  ac: aa0803e0  mov x0, x8                      // return value(x0) was overwritten by 0xdc(220)
  b0: a94257f6  ldp x22, x21, [sp, #32]
  b4: a9415ff8  ldp x24, x23, [sp, #16]
  b8: a8c467fe  ldp x30, x25, [sp], #64
  bc: d65f03c0  ret

Does anyone know why the `internal_clone` function of aarch64 is affected by this patch?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D105169/new/

https://reviews.llvm.org/D105169