https://gcc.gnu.org/g:3f0e671b804eede6f6ece1d67b9a8eebfe7fa8e1
commit r17-1617-g3f0e671b804eede6f6ece1d67b9a8eebfe7fa8e1 Author: Muhammad Kamran <[email protected]> Date: Wed Jun 17 13:23:56 2026 +0000 libitm: Mark AArch64 asm features with build attributes Emit AArch64 build attributes for BTI and PAC from libitm's hand-written AArch64 assembly when __ARM_BUILDATTR64_FV is available. Keep the existing GNU property note emission as the fallback for toolchains that do not support the new attribute form. libitm/ChangeLog: * config/aarch64/sjlj.S (FEATURE_1_AND_MARK): Define. Use AArch64 build attributes when __ARM_BUILDATTR64_FV is available, otherwise emit a GNU property note. Diff: --- libitm/config/aarch64/sjlj.S | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/libitm/config/aarch64/sjlj.S b/libitm/config/aarch64/sjlj.S index 62ce4f8ee908..7774ff4399d3 100644 --- a/libitm/config/aarch64/sjlj.S +++ b/libitm/config/aarch64/sjlj.S @@ -146,7 +146,6 @@ GTM_longjmp: # define PAC_FLAG 0 #endif -/* Add a NT_GNU_PROPERTY_TYPE_0 note. */ #define GNU_PROPERTY(type, value) \ .section .note.gnu.property, "a"; \ .p2align 3; \ @@ -159,11 +158,30 @@ GTM_longjmp: .word value; \ .word 0; +#ifdef __ARM_BUILDATTR64_FV +/* Add AArch64 feature bits build attributes. */ +# define FEATURE_1_AND_MARK(value) \ + .aeabi_subsection aeabi_feature_and_bits, optional, ULEB128; \ + .if ((value) & FEATURE_1_BTI); \ + .aeabi_attribute Tag_Feature_BTI, 1; \ + .else; \ + .aeabi_attribute Tag_Feature_BTI, 0; \ + .endif; \ + .if ((value) & FEATURE_1_PAC); \ + .aeabi_attribute Tag_Feature_PAC, 1; \ + .else; \ + .aeabi_attribute Tag_Feature_PAC, 0; \ + .endif; +#else +/* Add a NT_GNU_PROPERTY_TYPE_0 note. */ +# define FEATURE_1_AND_MARK(value) GNU_PROPERTY (FEATURE_1_AND, value) +#endif + #if defined(__linux__) || defined(__FreeBSD__) .section .note.GNU-stack, "", %progbits -/* Add GNU property note if built with branch protection. */ +/* Add markings if built with branch protection. */ # if (BTI_FLAG|PAC_FLAG) != 0 -GNU_PROPERTY (FEATURE_1_AND, BTI_FLAG|PAC_FLAG) +FEATURE_1_AND_MARK (BTI_FLAG|PAC_FLAG) # endif #endif
