[llvm-readobj][test] - Test "Format" values.

[grimar]

Summary

This adds testing for the "Format" field printed with --file-headers.

llvm-readelf doesn't use them, so only llvm-readobj needs to be tested.

All possible values are defined in ELFObjectFile<ELFT>::getFileFormatName().
and tested by D86625. Here we test just a few arbitrary ones.

[grimar]

Ping.

[jhenderson]

This is essentially testing the getFileFormatName function in ELFObjectFile.h, which is part of the Object library, not part of llvm-readobj. I'm not sure exhaustively testing all the possible values should be done in an llvm-readobj test. There should be an llvm-readobj test that shows that the Format is printed for one or two given values, but the getFileFormatName function should be tested in Object tests (probably best in gtest unit tests), in my opinion.

[grimar]

OK. I'll prepare a different patch and update this later.

[grimar]

• Addressed review comment.

[jhenderson]

LGTM.

llvm/test/tools/llvm-readobj/ELF/file-header-format.test

2

28

If you're going to use the default for CLASS and DATA, I'd do the same for MACHINE too, with EM_NONE as the default. Up to you though.

llvm/test/tools/llvm-readobj/ELF/file-header-format.test

+## This tests "Format" values printed by llvm-readobj.
+
+## The "Format" value printed depends on values stored in e_ident[EI_CLASS],
+## e_ident[EI_DATA] and e_machine fields of an ELF file header.
+## We test all possible values in unittests\Object\ELFObjectFileTest.cpp,
+## here we test just a few of them to demonstrate that llvm-readobj prints the same.
+
+# RUN: yaml2obj %s -o %t.none64.o
+# RUN: llvm-readobj --file-headers %t.none64.o | FileCheck %s -DFMT="elf64-unknown"
+
+# RUN: yaml2obj %s -o %t.none32.o -DCLASS=32
+# RUN: llvm-readobj --file-headers %t.none32.o | FileCheck %s -DFMT="elf32-unknown"
+
+# RUN: yaml2obj %s -o %t.i386-32.o -DMACHINE=EM_386 -DCLASS=32
+# RUN: llvm-readobj --file-headers %t.i386-32.o | FileCheck %s -DFMT="elf32-i386"
+
+# RUN: yaml2obj %s -o %t.x86_64.o -DMACHINE=EM_X86_64
+# RUN: llvm-readobj --file-headers %t.x86_64.o | FileCheck %s -DFMT="elf64-x86-64"
+
+# CHECK: Format: [[FMT]]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[CLASS=64]]
+  Data:    ELFDATA2[[DATA=LSB]]
+  Type:    ET_REL
+  Machine: [[MACHINE=EM_NONE]]