Unbreak ASan runtime in the simulators.
Summary:
861b69faee5df8d4e13ef316c7474a10e4069e81 (rdar://problem/
58789439) while
fixing symbolization for TSan completely broke ASan's runtime for the
simulators.
The problem with the previous patch is that the memory passed to
`putenv()` was poisoned and when passed to `putenv()` it tripped
an interceptor for `strchr()` which saw the memory was poisoned and
raised an ASan issue.
The memory was poisoned because `AtosSymbolizerProcess` objects
are created using ASan's internal allocator. Memory from this
allocator gets poisoned with `kAsanInternalHeapMagic`.
To workaround this, this patch makes the memory for the environment
variable entry a global variable that isn't poisoned.
This pass also adds a `DCHECK(getenv(K_ATOS_ENV_VAR))` because the
following DCHECK would crash because `internal_strcmp()` doesn't
work on nullptr.
rdar://problem/
62067724
Reviewers: kubamracek, yln
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D78525