[llvm] Allow "[[FLAGS=<none>]]" value in the ELF Fileheader Flags field (PR #143845)

[James Henderson via llvm-commits]

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@@ -0,0 +1,48 @@
+## Test for FileHeader Flags; when FLAGS variable isn't defined, the e_flags value is 0, otherwise it's the specified value
+
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj -h %t | FileCheck %s --check-prefixes=CHECK,NO-FLAG
+
+# RUN: yaml2obj %s -o %t -DFLAGS=[EF_AMDGPU_MACH_AMDGCN_GFX900]
+# RUN: llvm-readobj -h %t | FileCheck %s --check-prefixes=CHECK,FLAG
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  OSABI:           ELFOSABI_AMDGPU_HSA
+  Type:            ET_EXEC
+  Machine:         EM_AMDGPU
+  Flags:           [[FLAGS=<none>]]
+
+# CHECK:              Format: elf64-amdgpu
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jh7370 wrote:

You don't need to check every single field. Just check what's actually relevant to the test, i.e. the `Flags` field.

https://github.com/llvm/llvm-project/pull/143845