[lld] [llvm] [lld][AArch64][Build Attributes] Add support for AArch64 Build Attributes (PR #144082)

[Peter Smith via llvm-commits]

================
@@ -1,26 +1,49 @@
 // REQUIRES: aarch64
-// RUN: llvm-mc -triple=aarch64 %s -filetype=obj -o %t.o
-// RUN: ld.lld %t.o --shared -o %t.so
-// RUN: llvm-readelf --sections %t.so | FileCheck %s
-// RUN: ld.lld %t.o -o %t
-// RUN: llvm-readelf --sections %t | FileCheck %s
-// RUN: ld.lld -r %t.o -o %t2.o
-// RUN: llvm-readelf --sections %t2.o | FileCheck %s
-
-/// File has a Build attributes section. This should not appear in
-/// ET_EXEC or ET_SHARED files as there is no requirement for it to
-/// do so. FIXME, the ld -r (relocatable link) should output a single
-/// merged build attributes section. When full support is added in
-/// ld.lld this test should be updated.
+// RUN: rm -rf %t && split-file %s %t && cd %t
 
+// RUN: llvm-mc -triple=aarch64 -filetype=obj %s -o %t1.o
+// RUN: llvm-mc -triple=aarch64 -filetype=obj merged-2.s -o %t2.o
+// RUN: llvm-mc -triple=aarch64 -filetype=obj 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-prefix=NOTE
+
----------------
smithp35 wrote:

Can we add a summary of what we are intending to test. Something like
```
Combine 3 files with build attributes and check the merged properties. Each as has the same PAuth information so we expect this to propagate to the output. The only AND feature in common to all 3 files is BTI so we only expect to see that set in the output.
```

https://github.com/llvm/llvm-project/pull/144082