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. |
| @@ -26,6 +26,7 @@ builtin_check_c_compiler_flag("-Xclang -mcode-object-version=none" COMPILER_RT_H | |||
| builtin_check_c_compiler_flag(-Wbuiltin-declaration-mismatch COMPILER_RT_HAS_WBUILTIN_DECLARATION_MISMATCH_FLAG) | |||
| builtin_check_c_compiler_flag(/Zl COMPILER_RT_HAS_ZL_FLAG) | |||
| builtin_check_c_compiler_flag(-fcf-protection=full COMPILER_RT_HAS_FCF_PROTECTION_FLAG) | |||
| builtin_check_c_compiler_flag(-nostdinc++ COMPILER_RT_HAS_NOSTDINCXX_FLAG) | |||
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By the way, I wonder if builtin_check_c_compiler_flag handles C++ flags correctly. It may depend on the compiler, I guess.
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Yes, both gcc and clang (i.e. as opposed to g++ and clang++) accept this flag.
| @@ -836,7 +839,7 @@ else () | |||
| append_list_if(COMPILER_RT_ENABLE_CET -fcf-protection=full BUILTIN_CFLAGS) | |||
| endif() | |||
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| append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 BUILTIN_CFLAGS) | |||
| append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ BUILTIN_CFLAGS) | |||
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[note] If a separate builtin_check_cxx_compiler_flag function would be required for any C++ compiler, BUILTIN_CFLAGS may have to be updated here as well.
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As noted in the other comment, it doesn't seem to be a problem to pass this to the C compiler as well.
| // This asm snippet is used to force the creation of a frame record when | ||
| // calling the EmuPAC functions. This is important because the EmuPAC functions | ||
| // may crash if an auth failure is detected and may be unwound past using a | ||
| // frame pointer based unwinder. | ||
| #ifdef __GCC_HAVE_DWARF2_CFI_ASM | ||
| #define CFI_INST(inst) inst | ||
| #else | ||
| #define CFI_INST(inst) | ||
| #endif |
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It is possible to emit WinCFI information as well by means of .seh_* directives, though I'm not sure if it is important here.
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I'm not familiar with WinCFI so I'll leave that as a followup in case anyone is interested in adding it.
| __asm__(".globl __emupac_pacda\n" | ||
| "__emupac_pacda:\n" FRAME_POINTER_WRAP(__emupac_pacda_impl)); |
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__emupac_pacda should probably be wrapped with FRAME_POINTER_WRAP on both lines.
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I guess you mean ASM_SYMBOL? Yes, done.
| __asm__(".globl __emupac_autda\n" | ||
| "__emupac_autda:\n" FRAME_POINTER_WRAP(__emupac_autda_impl)); |
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Same for __emupac_autda.
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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
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