[LTO] Driver support for -lto_library flag #38264
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This commit adds support for the -lto_library flag, allowing users to specify a custom LTO library on Darwin. This also fixes an issue where the default LTO library is used even if Driver is run from inside an alternate toolchain.
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@swift-ci smoke test |
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Thank you for your contribution! CI is currently limited to established contributors, so you'll need someone with Contributor access to be able to invoke CI. (I can do that for you) @swift-ci please smoke test Also, given that the swift-driver is now the default driver as of Xcode 13, could you also implement this in the swift-driver? It is structured somewhat similarly, so it shouldn't be too difficult now that you've done this work in the legacy driver. |
include/swift/Option/Options.td
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| Flags<[FrontendOption, NoInteractiveOption]>, | ||
| HelpText<"Specify the LTO type to either 'llvm-thin' or 'llvm-full'">; | ||
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| def lto_library : Separate<["-"], "lto_library">, |
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Tiny nitpick: we usually prefer dashes to separate pieces of arguments, e.g. -lto-library.
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Ah, I see this is passed down to the linker. Still, I think we should promote linker-style arguments to Swift-style when we expose them from the Driver.
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Simple enough. Done 👍
I actually already have. As this is my first PR here I was waiting to see the feedback on this one before opening that one. |
Co-authored-by: Owen Voorhees <[email protected]>
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@harlanhaskins Could you run the tests? |
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@owenv What is the procedure now that the tests are done? Anything else I should do? |
| } else { | ||
| // Check for relative libLTO.dylib. This would be the expected behavior in an | ||
| // Xcode toolchain. | ||
| StringRef P = llvm::sys::path::parent_path(getDriver().getSwiftProgramPath()); |
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I think P is going to be <toolchain root>/usr/bin/ here, so we'll end up checking for libLTO in <toolchain root>/usr/bin/lib instead of <toolchain root>/usr/lib. I can't think of a good way to write a lit test for this unfortunately.
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Thanks for pointing this out. Fixed in latest commit.
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@swift-ci please test Windows |
3 participants
This commit adds support for the -lto_library flag, allowing users to specify a custom LTO library on Darwin. This also fixes an issue where the default LTO library is used even if Driver is run from inside an alternate toolchain.
@gottesmm