rustc: Add an option to default hidden visibility #47889
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This commit adds a new option to target specifictions to specify that symbols should be "hidden" visibility by default in LLVM. While there are no existing targets that take advantage of this the `wasm32-unknown-unknown` target will soon start to use this visibility. The LLD linker currently interprets `hidden` as "don't export this from the wasm module" which is what we want for 90% of our functions. While the LLD linker does have a "export this symbol" argument which is what we use for other linkers, it was also somewhat easier to do this change instead which'll involve less arguments flying around. Additionally there's no need for non-`hidden` visibility for most of our symbols! This change should not immediately impact the wasm targets as-is, but rather this is laying the foundations for soon integrating LLD as a linker for wasm code.
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r? @cramertj (rust_highfive has picked a reviewer for you, use r? to override) |
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@bors r+ I read through it, and the logic all seems good to me. Feel free to re-r? if you'd prefer someone with more LLVM familiarity take a look. |
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📌 Commit a2cc5d6 has been approved by |
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…, r=cramertj rustc: Add an option to default hidden visibility This commit adds a new option to target specifictions to specify that symbols should be "hidden" visibility by default in LLVM. While there are no existing targets that take advantage of this the `wasm32-unknown-unknown` target will soon start to use this visibility. The LLD linker currently interprets `hidden` as "don't export this from the wasm module" which is what we want for 90% of our functions. While the LLD linker does have a "export this symbol" argument which is what we use for other linkers, it was also somewhat easier to do this change instead which'll involve less arguments flying around. Additionally there's no need for non-`hidden` visibility for most of our symbols! This change should not immediately impact the wasm targets as-is, but rather this is laying the foundations for soon integrating LLD as a linker for wasm code.
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This commit adds a new option to target specifictions to specify that symbols
should be "hidden" visibility by default in LLVM. While there are no existing
targets that take advantage of this the
wasm32-unknown-unknowntarget willsoon start to use this visibility. The LLD linker currently interprets
hiddenas "don't export this from the wasm module" which is what we want for 90% of our
functions. While the LLD linker does have a "export this symbol" argument which
is what we use for other linkers, it was also somewhat easier to do this change
instead which'll involve less arguments flying around. Additionally there's no
need for non-
hiddenvisibility for most of our symbols!This change should not immediately impact the wasm targets as-is, but rather
this is laying the foundations for soon integrating LLD as a linker for wasm
code.