[PATCH] D13568: New MSan mapping layout (compiler-rt part)

[Evgeniy Stepanov via llvm-commits]

eugenis created this revision.
eugenis added a reviewer: samsonov.
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This is an implementation of https://github.com/google/sanitizers/issues/579

It has a number of advantages over the current mapping:
- works for non-PIE executables
- does not require ASLR; as a consequence, debugging MSan programs in gdb no longer requires "set disable-randomization off"
- supports linux kernels >=4.1.2
- the code is marginally faster and smaller

This is an ABI break. We never really promised ABI stability, but this patch includes a courtesy escape hatch: a compile-time macro that reverts back to the old mapping layout. The same macro will be used in the llvm part of the patch, their definitions have to match, of course.

Repository:
  rL LLVM

http://reviews.llvm.org/D13568

Files:
  lib/msan/msan.h
  lib/msan/msan_allocator.cc
  test/msan/mmap.cc
  test/msan/strlen_of_shadow.cc
  test/sanitizer_common/TestCases/Posix/decorate_proc_maps.cc

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