[LoongArch] Parse LoongArch base ABI in ObjectYAML and llvm-readobj

[SixWeining]

Summary

LoongArch e_flags definition:
https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_e_flags_identifies_abi_type_and_version

[xry111]

Is https://github.com/loongson/LoongArch-Documentation/pull/47 (using 0x1, 0x2, 0x3 for ILP32S/F/D and use EI_CLASS to distinguish LP64 and ILP32) dead?

[jhenderson]

Where you've added the contents to different files, you seeme to have added them at differenet relative places. For ease of reading, it would be better to keep platform-specific code in the same order in each file (I acknowledge it isn't perfect as it stands anyway, but we should avoid making it worse). Specifically, in same places, you've made your changes before the corresponding AVR block, and in others you've made them after. It don't care about the exact ordering, as long as it's consistent across the files.

llvm/test/Object/LoongArch/elf-flags.yaml

1 ↗

(On Diff #446407)

I don't think the Object library is the place for this testing, as the test tests functionality in ObjectYAML and llvm-readobj code, not in the Object library. I think you should split the test into two tests as follows:

1. In test/ObjectYAML, have a test that uses yaml2obj to generate object files that are converted back to YAML using obj2yaml. Check the resultant YAML contains the appropriate flags.
2. In test/tools/llvm-readobj, use yaml2obj to generate object files, and use llvm-readobj (and llvm-readelf) to inspect them.

62–67 ↗

(On Diff #446407)

As you're only testing the flags, you don't need most of these lines. Just the Flags line would be enough.

[SixWeining]

Add referenced documentation in comment.

[SixWeining]

In D130238#3667996, @xry111 wrote:

Is https://github.com/loongson/LoongArch-Documentation/pull/47 (using 0x1, 0x2, 0x3 for ILP32S/F/D and use EI_CLASS to distinguish LP64 and ILP32) dead?

Thanks.
I add some comments in the e_flags definition just now. If that PR get merged, let me update the definition.

[SixWeining]

Remove unnecessary check lines.

llvm/test/Object/LoongArch/elf-flags.yaml

1 ↗

(On Diff #446407)

Thanks. But seems other archs also put the test in the same place. And I saw no platform-specific test in test/ObjectYAML. What should I do?

62–67 ↗

(On Diff #446407)

Sounds good. Thanks.

[jhenderson]

llvm/test/Object/LoongArch/elf-flags.yaml

62–67 ↗

(On Diff #446441)

We don't need strict whitespace testing here, so let's neaten this all up.

1 ↗

(On Diff #446407)

I might look into fixing the other testing at some point to be in the right place. A quick look shows testing of MIPS e_flags in tools/obj2yaml, so perhaps the ob2yaml aspect can go there? The test would be named something like loong-arch-eflags.yaml, for similarity.

However, I don't feel strongly about this, so if you prefer to stick with existing precedent, that's fine.

[SixWeining]

Place the test to tools/llvm-readobj and tools/obj2yaml.

[SixWeining]

llvm/test/Object/LoongArch/elf-flags.yaml

62–67 ↗

(On Diff #446441)

Yes. Thanks.

1 ↗

(On Diff #446407)

Thanks. I think the MIPS approach makes sense.

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/loongarch-eflags.test

4

Minor nit: we're tending to move away from piping to a file in favour of using -o to write the output to that file. The logic is that it's easier to copy and paste the command from the test output to reproduce the test run.

65

Didn't see this earlier, sorry, but yaml2obj has an option (which might not have been available when existing tests were written) to allow text substitution within the YAML, a bit like FileCheck's -D option. Approximate example (not tested, but should be enough of an idea to get it to work):

# RUN: yaml2obj %s -o %t-lp64s -DFLAG=LP64S

...

--- !ELF
FileHeader:
  Class:           ELFCLASS64
  Data:            ELFDATA2LSB
  Type:            ET_EXEC
  Machine:         EM_LOONGARCH
  Flags:           [ EF_LOONGARCH_BASE_ABI_[[FLAG]] ]

This will allow you to only have one YAML block.

65

Missed that there was different Class values in some of the YAML blocks, but that can be solved in the same manner with a different variable.

llvm/test/tools/obj2yaml/ELF/loongarch-eflags.yaml

4

Same comments as the other test re. -D and -o options.

[SixWeining]

Use -D and -o options for yaml2obj.

llvm/test/tools/llvm-readobj/ELF/loongarch-eflags.test

4

OK. Thanks.

65

Thanks. Yes, this can reduce many lines.

[jhenderson]

LGTM.

[MaskRay]

Looks great!

llvm/include/llvm/BinaryFormat/ELF.h

920

Add a comma for the last element so that when a new one is added, the contributor doesn't have to touch the mask line.

llvm/test/tools/llvm-readobj/ELF/loongarch-eflags.test

27

Align Flags with ] 2 lines below. For readability, indent EF_LOONGARCH_BASE_ABI_LP64S by 2 spaces

llvm/test/tools/obj2yaml/ELF/loongarch-eflags.yaml

30

You can delete ...

[SixWeining]

indent

llvm/test/tools/obj2yaml/ELF/loongarch-eflags.yaml

30

Yes. And the same as llvm/test/tools/llvm-readobj/ELF/loongarch-eflags.test. Thanks.

llvm/include/llvm/BinaryFormat/ELF.h

enum : unsigned {
   EF_CSKY_EFV3 = 0x3000000
 };
 
 // ELF Relocation types for CSKY
 enum {
 #include "ELFRelocs/CSKY.def"
 };
 
+// LoongArch Specific e_flags
+enum : unsigned {
+  // Reference: https://github.com/loongson/LoongArch-Documentation.
+  // The last commit hash (main branch) is
+  // 99016636af64d02dee05e39974d4c1e55875c45b.
+  // Note that there is an open PR
+  // https://github.com/loongson/LoongArch-Documentation/pull/47
+  // talking about using 0x1, 0x2, 0x3 for ILP32S/F/D and use EI_CLASS to
+  // distinguish LP64 and ILP32. If this PR get merged, we will update
+  // the definition here.
+  // Base ABI Types.
+  EF_LOONGARCH_BASE_ABI_LP64S = 0x1,  // LP64 soft-float ABI
+  EF_LOONGARCH_BASE_ABI_LP64F = 0x2,  // LP64 single-float ABI
+  EF_LOONGARCH_BASE_ABI_LP64D = 0x3,  // LP64 double-float ABI
+  EF_LOONGARCH_BASE_ABI_ILP32S = 0x5, // ILP32 soft-float ABI
+  EF_LOONGARCH_BASE_ABI_ILP32F = 0x6, // ILP32 single-float ABI
+  EF_LOONGARCH_BASE_ABI_ILP32D = 0x7, // ILP32 double-float ABI
+  EF_LOONGARCH_BASE_ABI_MASK = 0x7    // Mask for selecting base ABI
+};
+
 // ELF Relocation types for LoongArch
 enum {
 #include "ELFRelocs/LoongArch.def"
 };
 
 #undef ELF_RELOC
 
 // Section header.

llvm/lib/ObjectYAML/ELFYAML.cpp

case ELF::EM_AVR:
     BCaseMask(EF_AVR_ARCH_XMEGA2, EF_AVR_ARCH_MASK);
     BCaseMask(EF_AVR_ARCH_XMEGA3, EF_AVR_ARCH_MASK);
     BCaseMask(EF_AVR_ARCH_XMEGA4, EF_AVR_ARCH_MASK);
     BCaseMask(EF_AVR_ARCH_XMEGA5, EF_AVR_ARCH_MASK);
     BCaseMask(EF_AVR_ARCH_XMEGA6, EF_AVR_ARCH_MASK);
     BCaseMask(EF_AVR_ARCH_XMEGA7, EF_AVR_ARCH_MASK);
     BCase(EF_AVR_LINKRELAX_PREPARED);
     break;
+  case ELF::EM_LOONGARCH:
+    BCaseMask(EF_LOONGARCH_BASE_ABI_ILP32S, EF_LOONGARCH_BASE_ABI_MASK);
+    BCaseMask(EF_LOONGARCH_BASE_ABI_ILP32F, EF_LOONGARCH_BASE_ABI_MASK);
+    BCaseMask(EF_LOONGARCH_BASE_ABI_ILP32D, EF_LOONGARCH_BASE_ABI_MASK);
+    BCaseMask(EF_LOONGARCH_BASE_ABI_LP64S, EF_LOONGARCH_BASE_ABI_MASK);
+    BCaseMask(EF_LOONGARCH_BASE_ABI_LP64F, EF_LOONGARCH_BASE_ABI_MASK);
+    BCaseMask(EF_LOONGARCH_BASE_ABI_LP64D, EF_LOONGARCH_BASE_ABI_MASK);
+    break;
   case ELF::EM_RISCV:
     BCase(EF_RISCV_RVC);
     BCaseMask(EF_RISCV_FLOAT_ABI_SOFT, EF_RISCV_FLOAT_ABI);
     BCaseMask(EF_RISCV_FLOAT_ABI_SINGLE, EF_RISCV_FLOAT_ABI);
     BCaseMask(EF_RISCV_FLOAT_ABI_DOUBLE, EF_RISCV_FLOAT_ABI);
     BCaseMask(EF_RISCV_FLOAT_ABI_QUAD, EF_RISCV_FLOAT_ABI);
     BCase(EF_RISCV_RVE);
     BCase(EF_RISCV_TSO);

llvm/test/tools/llvm-readobj/ELF/loongarch-eflags.test

+## Check llvm-readobj is able to decode all possible LoongArch e_flags field values.
+
+# RUN: yaml2obj %s -o %t-lp64s -DCLASS=64 -DFLAG=LP64S
+# RUN: llvm-readobj -h %t-lp64s | FileCheck --check-prefix=READOBJ-LP64S %s
+# RUN: llvm-readelf -h %t-lp64s | FileCheck --check-prefix=READELF-LP64S --match-full-lines %s
+
+# RUN: yaml2obj %s -o %t-lp64f -DCLASS=64 -DFLAG=LP64F
+# RUN: llvm-readobj -h %t-lp64f | FileCheck --check-prefix=READOBJ-LP64F %s
+# RUN: llvm-readelf -h %t-lp64f | FileCheck --check-prefix=READELF-LP64F --match-full-lines %s
+
+# RUN: yaml2obj %s -o %t-lp64d -DCLASS=64 -DFLAG=LP64D
+# RUN: llvm-readobj -h %t-lp64d | FileCheck --check-prefix=READOBJ-LP64D %s
+# RUN: llvm-readelf -h %t-lp64d | FileCheck --check-prefix=READELF-LP64D --match-full-lines %s
+
+# RUN: yaml2obj %s -o %t-ilp32s -DCLASS=32 -DFLAG=ILP32S
+# RUN: llvm-readobj -h %t-ilp32s | FileCheck --check-prefix=READOBJ-ILP32S %s
+# RUN: llvm-readelf -h %t-ilp32s | FileCheck --check-prefix=READELF-ILP32S --match-full-lines %s
+
+# RUN: yaml2obj %s -o %t-ilp32f -DCLASS=32 -DFLAG=ILP32F
+# RUN: llvm-readobj -h %t-ilp32f | FileCheck --check-prefix=READOBJ-ILP32F %s
+# RUN: llvm-readelf -h %t-ilp32f | FileCheck --check-prefix=READELF-ILP32F --match-full-lines %s
+
+# RUN: yaml2obj %s -o %t-ilp32d -DCLASS=32 -DFLAG=ILP32D
+# RUN: llvm-readobj -h %t-ilp32d | FileCheck --check-prefix=READOBJ-ILP32D %s
+# RUN: llvm-readelf -h %t-ilp32d | FileCheck --check-prefix=READELF-ILP32D --match-full-lines %s
+
+# READOBJ-LP64S: Flags [ (0x1)
+# READOBJ-LP64S-NEXT: EF_LOONGARCH_BASE_ABI_LP64S (0x1)
+# READOBJ-LP64S-NEXT: ]
+
+# READOBJ-LP64F: Flags [ (0x2)
+# READOBJ-LP64F-NEXT: EF_LOONGARCH_BASE_ABI_LP64F (0x2)
+# READOBJ-LP64F-NEXT: ]
+
+# READOBJ-LP64D: Flags [ (0x3)
+# READOBJ-LP64D-NEXT: EF_LOONGARCH_BASE_ABI_LP64D (0x3)
+# READOBJ-LP64D-NEXT: ]
+
+# READOBJ-ILP32S: Flags [ (0x5)
+# READOBJ-ILP32S-NEXT: EF_LOONGARCH_BASE_ABI_ILP32S (0x5)
+# READOBJ-ILP32S-NEXT: ]
+
+# READOBJ-ILP32F: Flags [ (0x6)
+# READOBJ-ILP32F-NEXT: EF_LOONGARCH_BASE_ABI_ILP32F (0x6)
+# READOBJ-ILP32F-NEXT: ]
+
+# READOBJ-ILP32D: Flags [ (0x7)
+# READOBJ-ILP32D-NEXT: EF_LOONGARCH_BASE_ABI_ILP32D (0x7)
+# READOBJ-ILP32D-NEXT: ]
+
+# READELF-LP64S: Flags: 0x1, LP64, SOFT-FLOAT
+# READELF-LP64F: Flags: 0x2, LP64, SINGLE-FLOAT
+# READELF-LP64D: Flags: 0x3, LP64, DOUBLE-FLOAT
+# READELF-ILP32S: Flags: 0x5, ILP32, SOFT-FLOAT
+# READELF-ILP32F: Flags: 0x6, ILP32, SINGLE-FLOAT
+# READELF-ILP32D: Flags: 0x7, ILP32, DOUBLE-FLOAT
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS[[CLASS]]
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_LOONGARCH
+  Flags:           [ EF_LOONGARCH_BASE_ABI_[[FLAG]] ]
+...

llvm/test/tools/obj2yaml/ELF/loongarch-eflags.yaml

+## Check obj2yaml is able to decode all possible LoongArch e_flags field values.
+
+# RUN: yaml2obj %s -o %t-lp64s -DCLASS=64 -DFLAG=LP64S
+# RUN: obj2yaml %t-lp64s | FileCheck -DFLAG=LP64S %s
+
+# RUN: yaml2obj %s -o %t-lp64f -DCLASS=64 -DFLAG=LP64F
+# RUN: obj2yaml %t-lp64f | FileCheck -DFLAG=LP64F %s
+
+# RUN: yaml2obj %s -o %t-lp64d -DCLASS=64 -DFLAG=LP64D
+# RUN: obj2yaml %t-lp64d | FileCheck -DFLAG=LP64D %s
+
+# RUN: yaml2obj %s -o %t-ilp32s -DCLASS=32 -DFLAG=ILP32S
+# RUN: obj2yaml %t-ilp32s | FileCheck -DFLAG=ILP32S %s
+
+# RUN: yaml2obj %s -o %t-ilp32f -DCLASS=32 -DFLAG=ILP32F
+# RUN: obj2yaml %t-ilp32f | FileCheck -DFLAG=ILP32F %s
+
+# RUN: yaml2obj %s -o %t-ilp32d -DCLASS=32 -DFLAG=ILP32D
+# RUN: obj2yaml %t-ilp32d | FileCheck -DFLAG=ILP32D %s
+
+# CHECK: Flags: [ EF_LOONGARCH_BASE_ABI_[[FLAG]] ]
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS[[CLASS]]
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_LOONGARCH
+  Flags:           [ EF_LOONGARCH_BASE_ABI_[[FLAG]] ]
+...

llvm/tools/llvm-readobj/ELFDumper.cpp

const EnumEntry<unsigned> ElfHeaderAVRFlags[] = {
   LLVM_READOBJ_ENUM_ENT(ELF, EF_AVR_ARCH_XMEGA3),
   LLVM_READOBJ_ENUM_ENT(ELF, EF_AVR_ARCH_XMEGA4),
   LLVM_READOBJ_ENUM_ENT(ELF, EF_AVR_ARCH_XMEGA5),
   LLVM_READOBJ_ENUM_ENT(ELF, EF_AVR_ARCH_XMEGA6),
   LLVM_READOBJ_ENUM_ENT(ELF, EF_AVR_ARCH_XMEGA7),
   ENUM_ENT(EF_AVR_LINKRELAX_PREPARED, "relaxable"),
 };
 
+const EnumEntry<unsigned> ElfHeaderLoongArchFlags[] = {
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_ILP32S, "ILP32, SOFT-FLOAT"),
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_ILP32F, "ILP32, SINGLE-FLOAT"),
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_ILP32D, "ILP32, DOUBLE-FLOAT"),
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_LP64S, "LP64, SOFT-FLOAT"),
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_LP64F, "LP64, SINGLE-FLOAT"),
+  ENUM_ENT(EF_LOONGARCH_BASE_ABI_LP64D, "LP64, DOUBLE-FLOAT"),
+};
+
 
 const EnumEntry<unsigned> ElfSymOtherFlags[] = {
   LLVM_READOBJ_ENUM_ENT(ELF, STV_INTERNAL),
   LLVM_READOBJ_ENUM_ENT(ELF, STV_HIDDEN),
   LLVM_READOBJ_ENUM_ENT(ELF, STV_PROTECTED)
 };
 
 const EnumEntry<unsigned> ElfMipsSymOtherFlags[] = {
ElfFlags =
         printFlags(e.e_flags, makeArrayRef(ElfHeaderMipsFlags),
                    unsigned(ELF::EF_MIPS_ARCH), unsigned(ELF::EF_MIPS_ABI),
                    unsigned(ELF::EF_MIPS_MACH));
   else if (e.e_machine == EM_RISCV)
     ElfFlags = printFlags(e.e_flags, makeArrayRef(ElfHeaderRISCVFlags));
   else if (e.e_machine == EM_AVR)
     ElfFlags = printFlags(e.e_flags, makeArrayRef(ElfHeaderAVRFlags),
                           unsigned(ELF::EF_AVR_ARCH_MASK));
+  else if (e.e_machine == EM_LOONGARCH)
+    ElfFlags = printFlags(e.e_flags, makeArrayRef(ElfHeaderLoongArchFlags),
+                          unsigned(ELF::EF_LOONGARCH_BASE_ABI_MASK));
   Str = "0x" + utohexstr(e.e_flags);
   if (!ElfFlags.empty())
     Str = Str + ", " + ElfFlags;
   printFields(OS, "Flags:", Str);
   Str = to_string(e.e_ehsize) + " (bytes)";
   printFields(OS, "Size of this header:", Str);
   Str = to_string(e.e_phentsize) + " (bytes)";
   printFields(OS, "Size of program headers:", Str);
else if (E.e_machine == EM_AMDGPU) {
                      unsigned(ELF::EF_AMDGPU_FEATURE_SRAMECC_V4));
         break;
       }
     } else if (E.e_machine == EM_RISCV)
       W.printFlags("Flags", E.e_flags, makeArrayRef(ElfHeaderRISCVFlags));
     else if (E.e_machine == EM_AVR)
       W.printFlags("Flags", E.e_flags, makeArrayRef(ElfHeaderAVRFlags),
                    unsigned(ELF::EF_AVR_ARCH_MASK));
+    else if (E.e_machine == EM_LOONGARCH)
+      W.printFlags("Flags", E.e_flags, makeArrayRef(ElfHeaderLoongArchFlags),
+                   unsigned(ELF::EF_LOONGARCH_BASE_ABI_MASK));
     else
       W.printFlags("Flags", E.e_flags);
     W.printNumber("HeaderSize", E.e_ehsize);
     W.printNumber("ProgramHeaderEntrySize", E.e_phentsize);
     W.printNumber("ProgramHeaderCount", E.e_phnum);
     W.printNumber("SectionHeaderEntrySize", E.e_shentsize);
     W.printString("SectionHeaderCount",
                   getSectionHeadersNumString(this->Obj, this->FileName));