[clang] Pass-through remarks options to linker
Summary:
Propagate driver commandline remarks options to linker when LTO is enabled.
This gives novice user a convenient way to collect and filter remarks throughout
a typical toolchain invocation with sample profile and LTO using single switch
from the clang driver.
A typical use of this option from clang command-line:
* Using -Rpass* options to print remarks to screen:
clang -fuse-ld=lld -flto=thin -fprofile-sample-use=foo_sample.txt
-Rpass=inline -Rpass-missed=inline -Rpass-analysis=inline
-fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=100 -o foo foo.cpp
Remarks will be dumped to screen from both pre-lto and lto
compilation.
* Using serialized remarks options
clang -fuse-ld=lld -flto=thin -fprofile-sample-use=foo_sample.txt
-fsave-optimization-record
-fdiagnostics-show-hotness -fdiagnostics-hotness-threshold=100 -o foo foo.cpp
This will produce multiple yaml files containing optimization remarks:
1. foo.opt.yaml : remarks from pre-lto
2. foo.opt.ld.yaml.thin.1.yaml: remark during lto
Differential Revision: https://reviews.llvm.org/D85810