Reapply "compiler-rt: Introduce runtime functions for emulated PAC." #148094
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Created using spr 1.3.6-beta.1
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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Thanks - this version no longer seems to break my macOS build, and no longer fails the test on windows of arm64. |
Created using spr 1.3.6-beta.1
| #ifdef __APPLE__ | ||
| #define ASM_SYMBOL(symbol) "_" #symbol | ||
| #else | ||
| #define ASM_SYMBOL(symbol) #symbol | ||
| #endif |
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For the sake of completeness, it seems there is another exception, Arm64EC ABI:
For ARM64EC functions with C linkage (whether compiled as C or by using extern "C"), a # is prepended to the decorated name.
This seems to be something Clang already knows about: for a trivial int f(void) { return 0; } source compiled with clang -target arm64ec-windows-msvc -S -o- /tmp/arm64ec-test.c it produces
// ...
.p2align 2
"#f": // @"#f"
.weak_anti_dep f
f = "#f"
// %bb.0: // %entry
mov w0, wzr
ret
// ...
Furthermore, some aliases are mentioned in AArch64MCInstLower.cpp. Please feel free to ignore / postpone this as long as builders are not affected.
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Yeah, I'm not sure what the right fix is or even if it needs a fix (ARM64EC seems to involve some sort of thunking mechanism so maybe this already works?) So let's wait to see if that is necessary.
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@cjacek Do you have time to try building this for ARM64EC and see if we need some change to it?
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Nevermind - I did manage to try building it myself. It does build fine - so that's good, not breaking anything. Not sure about the missing # for symbol names though - it might have issues if we'd ever try to use it. But it's also quite unsure if this is relevant at all for arm64ec (which essentially emulates x86_64 ABI with native aarch64 code).
| const uint64_t max_va_size = 48; | ||
| const uint64_t pac_mask = ((1ULL << 55) - 1) & ~((1ULL << max_va_size) - 1); | ||
| const uint64_t ttbr1_mask = 1ULL << 55; |
Created using spr 1.3.6-beta.1
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users/pcc/spr/reapply-compiler-rt-introduce-runtime-functions-for-emulated-pac
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…ated PAC." This reverts commit 0c0aa56. This time with the following fixes for buildbot failures: - Add underscore prefixes to symbol names on Apple platforms. - Modify the test so that it skips the crash tests on platforms where they are not expected to pass: - Platforms that implement FEAT_PAuth but not FEAT_FPAC (e.g. Apple M1, Cortex-A78C) - Platforms where DA key is disabled (e.g. older Linux kernels, Linux kernels with PAC disabled, likely Windows) Original commit message follows: The emulated PAC runtime functions emulate the ARMv8.3a pointer authentication instructions and are intended for use in heterogeneous testing environments. For more information, see the associated RFC: https://discourse.llvm.org/t/rfc-emulated-pac/85557 Reviewers: mstorsjo, pawosm-arm, atrosinenko Reviewed By: atrosinenko Pull Request: llvm/llvm-project#148094
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Hi @pcc , @atrosinenko , here is failed Would you take care of it? |
This reverts commit 0c0aa56.
This time with the following fixes for buildbot failures:
they are not expected to pass:
Apple M1, Cortex-A78C)
Linux kernels with PAC disabled, likely Windows)
Original commit message follows:
The emulated PAC runtime functions emulate the ARMv8.3a pointer
authentication instructions and are intended for use in heterogeneous
testing environments. For more information, see the associated RFC:
https://discourse.llvm.org/t/rfc-emulated-pac/85557