tree 48992a4857354f540919e311d0e6f89790b0a4cb
parent 1fbdf5120831849998817dfb2772183fa0b20684
author klimek <klimek@google.com> 1501592213 +0200
committer Marcel Hlopko <hlopko@google.com> 1547020427 +0100

Implement user experience for LIPO / ThinLTO users.

Add flag --convert_lipo_to_thinlto, which allows builds with LLVM to use
ThinLTO when the user specifies LIPO + FDO flags; if that flag is not set, and
the user requests a build with LLVM, the compile will now fail.

Add an attribute supports_lipo to the DefaultCpuToolchain crosstool proto and
skip default toolchains that do not support LIPO when the user has specified
LIPO flags in the toolchain selection; this enables CROSSTOOL files to cause
an implicit fallback to a hybrid / LIPO toolchain when using an LLVM toolchain
as the default.

Add a CrosstoolBuilder to MockCcSupport and add a new method
setupCrosstoolFromScratch that allows unit tests to fully control the setup.
The other methods available in MockCcSupport will always load in a default
CROSSTOOL file and may show different unit test results depending on the
content of that file.

RELNOTES: None.
PiperOrigin-RevId: 163819246