aarch64-linux: Default to FramePointer::NonLeaf #140832
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⌛ Trying commit fbaf582 with merge b5f9a0d36e6b3537b76a5aa710e1d5d13313f3d1... |
…use-frame-pointers, r=<try> aarch64-linux: Default to FramePointer::NonLeaf For aarch64-apple and aarch64-windows, platform docs state that code must use frame pointers correctly. This is because the AAPCS64 mandates that a platform specify its frame pointer conformance requirements: - Apple: https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Respect-the-purpose-of-specific-CPU-registers - Windows: https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#integer-registers - AAPCS64: https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer Unwinding code either requires unwind tables or frame pointers, and on aarch64 the expectation is that one can use frame pointers for this. Most Linux targets represent a motley variety of possible distributions, so it is unclear who to defer to on conformance, other than perhaps Arm. In the absence of a specific edict for a given aarch64-linux target, Rust will assume aarch64-linux targets also use non-leaf frame pointers. r? ghost try-job: aarch64-gnu try-job: aarch64-gnu-debug try-job: arm-android try-job: armhf-gnu try-job: dist-aarch64-linux try-job: dist-ohos try-job: test-various
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For aarch64-apple and aarch64-windows, platform docs state that code must use frame pointers correctly. This is because the AAPCS64 mandates that a platform specify its frame pointer conformance requirements: - Apple: https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Respect-the-purpose-of-specific-CPU-registers - Windows: https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#integer-registers - AAPCS64: https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer Unwinding code either requires unwind tables or frame pointers, and on aarch64 the expectation is that one can use frame pointers for this. Most Linux targets represent a motley variety of possible distributions, so it is unclear who to defer to on conformance, other than perhaps Arm. In the absence of a specific edict for a given aarch64-linux target, Rust will assume aarch64-linux targets use non-leaf frame pointers.
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…use-frame-pointers, r=<try> aarch64-linux: Default to FramePointer::NonLeaf For aarch64-apple and aarch64-windows, platform docs state that code must use frame pointers correctly. This is because the AAPCS64 mandates that a platform specify its frame pointer conformance requirements: - Apple: https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Respect-the-purpose-of-specific-CPU-registers - Windows: https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#integer-registers - AAPCS64: https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer Unwinding code either requires unwind tables or frame pointers, and on aarch64 the expectation is that one can use frame pointers for this. Most Linux targets represent a motley variety of possible distributions, so it is unclear who to defer to on conformance, other than perhaps Arm. In the absence of a specific edict for a given aarch64-linux target, Rust will assume aarch64-linux targets also use non-leaf frame pointers. r? ghost try-job: aarch64-gnu try-job: aarch64-gnu-debug try-job: arm-android try-job: armhf-gnu try-job: dist-aarch64-linux try-job: dist-ohos try-job: test-various
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cc re: OpenHarmony: @Amanieu @lubinglun I assume there's no objections to doing this? I can revert the change for your particular aarch64-linux targets if you want. |
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No specific objection for OpenHarmony, though I have a more general objection.
While this is required on Windows & Apple as per their docs, Linux doesn't actually specify whether a frame pointer is required and I would assume the default assumption is that it isn't since that is the default setting on GCC for aarch64-linux. AAPCS64 explicitly allows this as an option:
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@Amanieu What authority would you defer to? Who is gonna specify that requirement? Should we ask Linus Torvalds? |
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The aarch64-unknown-linux-gnu target was Unless we intend to remove the aarch64-unknown-linux-gnu target, I suppose, but that would make people much more mad. |
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Actually I just checked and it seems that I am incorrect: the default on AArch64 Linux for both GCC and Clang is to enable frame pointers for non-leaf functions. I withdraw my objection. Regarding authority, the target owner is Arm so they get the final say. However I would imagine that they would want to match the behavior of C compilers which they also contribute to. |
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Ah, well, yes, I would agree, I just figured the answer from Arm was the obvious one ("it puts the frame pointer in the register or else it gets the hose again") |
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☀️ Try build successful - checks-actions |
For aarch64-apple and aarch64-windows, platform docs state that code must use frame pointers correctly. This is because the AAPCS64 mandates that a platform specify its frame pointer conformance requirements:
Unwinding code either requires unwind tables or frame pointers, and on aarch64 the expectation is that one can use frame pointers for this. Most Linux targets represent a motley variety of possible distributions, so it is unclear who to defer to on conformance, other than perhaps Arm. In the absence of a specific edict for a given aarch64-linux target, Rust will assume aarch64-linux targets also use non-leaf frame pointers.
r? ghost
try-job: aarch64-gnu
try-job: aarch64-gnu-debug
try-job: arm-android
try-job: armhf-gnu
try-job: dist-aarch64-linux
try-job: dist-ohos
try-job: test-various