[lld] [llvm] [lld][AArch64][Build Attributes] Add support for converting AArch64 Build Attributes to GNU Properties (PR #131990)

[via llvm-commits]

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@@ -0,0 +1,20 @@
+# RUN: llvm-mc -triple=aarch64 -filetype=obj %s -o %t1.o
+# RUN: llvm-mc -triple=aarch64 -filetype=obj %p/Inputs/build-attributes-merged-2.s -o %t2.o
+# RUN: llvm-mc -triple=aarch64 -filetype=obj %p/Inputs/build-attributes-merged-3.s -o %t3.o
+# RUN: ld.lld -r %t1.o %t2.o %t3.o -o %t.merged.o
+# RUN: llvm-readelf -n %t.merged.o | FileCheck %s
+
+# CHECK: Displaying notes found in: .note.gnu.property
+# CHECK-NEXT:  Owner                Data size 	Description
+# CHECK-NEXT:  GNU                  0x00000028	NT_GNU_PROPERTY_TYPE_0 (property note)
+# CHECK-NEXT:    Properties:    aarch64 feature: BTI
+# CHECK-NEXT:        AArch64 PAuth ABI core info: platform 0x31 (unknown), version 0x13
+
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sivan-shani wrote:

The way I understand it we see here:

> Properties:    aarch64 feature: BTI

Because `build-attributes-merged-2` mark PAC as 0 and `build-attributes-merged-3` mark GCS as 0 (only BTI is 1 in all 3 files.)

We also see 

> AArch64 PAuth ABI core info: platform 0x31 (unknown), version 0x13

Since the build attributes contain `Tag_PAuth_Platform, 49` and `Tag_PAuth_Schema, 19`

https://github.com/llvm/llvm-project/pull/131990