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
diff --git a/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto b/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
index bd7235f..5170c0f 100644
--- a/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
+++ b/third_party/com/github/bazelbuild/bazel/src/main/protobuf/crosstool_config.proto
@@ -517,6 +517,7 @@
message DefaultCpuToolchain {
required string cpu = 1;
required string toolchain_identifier = 2;
+ optional bool supports_lipo = 3 [default = true];
}
// An entire crosstool release, containing the version number, a default target
