The embedded bitcode should always be prepared for LTO/ThinLTO Fixes #115344. Fixes #117220. There are currently two methods for generating bitcode that used for LTO. One method involves using `-C linker-plugin-lto` to emit object files as bitcode, which is the typical setting used by cargo. The other method is through `-C embed-bitcode=yes`. When using with `-C embed-bitcode=yes -C lto=no`, we run a complete non-LTO LLVM pipeline to obtain bitcode, then the bitcode is used for LTO. We run the Call Graph Profile Pass twice on the same module. This PR is doing something similar to LLVM's `buildFatLTODefaultPipeline`, obtaining the bitcode for embedding after running `buildThinLTOPreLinkDefaultPipeline`. r? nikic
The run-make test suite
The run-make test suite contains tests which are the most flexible out of all
the rust-lang/rust test suites. run-make
tests can basically contain arbitrary code, and are supported by the
run_make_support library.
Infrastructure
There are two kinds of run-make tests:
- The new
rmake.rsversion: this allows run-make tests to be written in Rust (withrmake.rsas the main test file). - The legacy
Makefileversion: this is what run-make tests were written with before support forrmake.rswas introduced.
The implementation for collecting and building the rmake.rs recipes (or
Makefiles) are in
src/tools/compiletest/src/runtest.rs,
in run_rmake_v2_test and run_rmake_legacy_test.
Rust-based run-make tests: rmake.rs
The setup for the rmake.rs version is a 3-stage process:
-
First, we build the
run_make_supportlibrary in bootstrap as a tool lib. -
Then, we compile the
rmake.rs"recipe" linking the support library and its dependencies in, and provide a bunch of env vars. We setup a directory structure withinbuild/<target>/test/run-make/<test-name>/ rmake.exe # recipe binary rmake_out/ # sources from test sources copied overand copy non-
rmake.rsinput support files over tormake_out/. The support library is made available as an extern prelude. -
Finally, we run the recipe binary and set
rmake_out/as the working directory.
Formatting
Note that files under tests/ are not formatted by ./x fmt,
use rustfmt tests/path/to/file.rs to format a specific file if desired.