When running tests in compiler-rt using the lit internal shell with the
following command:
```
LIT_USE_INTERNAL_SHELL=1 ninja check-compiler-rt
```
one common error that occurs is:
```
'XRAY_OPTIONS=patch_premain=false:verbosity=1': command not found
```
This error, along with over 50 similar "environment variable not found"
errors, appears across 35 files in complier-rt. These errors happen
because the environment variables are not being set correctly when the
internal shell is used, leading to commands failing due to unrecognized
environment variables.
This patch addresses the issue by using the `env` command to properly
set the environment variables before running the tests. By explicitly
setting the environment variables through `env`, the internal shell can
correctly interpret and apply them, allowing the tests to pass.
fixes: #102395
[link to
RFC](https://discourse.llvm.org/t/rfc-enabling-the-lit-internal-shell-by-default/80179)
Complete support for fast8:
- amend shadow size and mapping in runtime
- remove fast16 mode and -dfsan-fast-16-labels flag
- remove legacy mode and make fast8 mode the default
- remove dfsan-fast-8-labels flag
- remove functions in dfsan interface only applicable to legacy
- remove legacy-related instrumentation code and tests
- update documentation.
Reviewed By: stephan.yichao.zhao, browneee
Differential Revision: https://reviews.llvm.org/D103745
