[all-commits] [llvm/llvm-project] a67283: tsan: fix XMM register corruption in hacky call

[Dmitry Vyukov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a6728382c6de6211499ab83d708655947c8ce052
      https://github.com/llvm/llvm-project/commit/a6728382c6de6211499ab83d708655947c8ce052
  Author: Dmitry Vyukov <dvyukov at google.com>
  Date:   2021-11-12 (Fri, 12 Nov 2021)

  Changed paths:
    M compiler-rt/lib/tsan/rtl/tsan_rtl_amd64.S
    A compiler-rt/test/sanitizer_common/TestCases/frexp.cpp

  Log Message:
  -----------
  tsan: fix XMM register corruption in hacky call

The compiler does not recognize HACKY_CALL as a call
(we intentionally hide it from the compiler so that it can
compile non-leaf functions as leaf functions).
To compensate for that hacky call thunk saves and restores
all caller-saved registers. However, it saves only
general-purposes registers and does not save XMM registers.
This is a latent bug that was masked up until a recent "NFC" commit
d736002e90 ("tsan: move memory access functions to a separate file"),
which allowed more inlining and exposed the 10-year bug.
Save and restore caller-saved XMM registers (all) as well.

Currently the bug manifests as e.g. frexp interceptor messes the
return value and the added test fails with:
  i=8177 y=0.000000 exp=4

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D113742