[yaml2obj][obj2yaml][objdump] Handle MIPS COFF files (llvm#112591)

- handle IMAGE_FILE_MACHINE_R4000 machine type
- handle MIPS COFF relocations

llvm-objdump can now parse MIPS COFF files.

Author: hpoussin

llvm/include/llvm/Object/WindowsMachineFlag.h

@@ -43,6 +43,8 @@ template <typename T> Triple::ArchType getMachineArchType(T machine) {
   case COFF::IMAGE_FILE_MACHINE_ARM64EC:
   case COFF::IMAGE_FILE_MACHINE_ARM64X:
     return llvm::Triple::ArchType::aarch64;
+  case COFF::IMAGE_FILE_MACHINE_R4000:
+    return llvm::Triple::ArchType::mipsel;
   default:
     return llvm::Triple::ArchType::UnknownArch;
   }

llvm/include/llvm/ObjectYAML/COFFYAML.h

@@ -179,6 +179,10 @@ struct ScalarEnumerationTraits<COFF::RelocationTypeAMD64> {
   static void enumeration(IO &IO, COFF::RelocationTypeAMD64 &Value);
 };
 
+template <> struct ScalarEnumerationTraits<COFF::RelocationTypesMips> {
+  static void enumeration(IO &IO, COFF::RelocationTypesMips &Value);
+};
+
 template <>
 struct ScalarEnumerationTraits<COFF::RelocationTypesARM> {
   static void enumeration(IO &IO, COFF::RelocationTypesARM &Value);

llvm/lib/Object/COFFObjectFile.cpp

@@ -1132,6 +1132,8 @@ StringRef COFFObjectFile::getFileFormatName() const {
     return "COFF-ARM64EC";
   case COFF::IMAGE_FILE_MACHINE_ARM64X:
     return "COFF-ARM64X";
+  case COFF::IMAGE_FILE_MACHINE_R4000:
+    return "COFF-MIPS";
   default:
     return "COFF-<unknown arch>";
   }

llvm/lib/ObjectYAML/COFFYAML.cpp

@@ -183,6 +183,25 @@ void ScalarEnumerationTraits<COFF::RelocationTypeAMD64>::enumeration(
   ECase(IMAGE_REL_AMD64_SSPAN32);
 }
 
+void ScalarEnumerationTraits<COFF::RelocationTypesMips>::enumeration(
+    IO &IO, COFF::RelocationTypesMips &Value) {
+  ECase(IMAGE_REL_MIPS_ABSOLUTE);
+  ECase(IMAGE_REL_MIPS_REFHALF);
+  ECase(IMAGE_REL_MIPS_REFWORD);
+  ECase(IMAGE_REL_MIPS_JMPADDR);
+  ECase(IMAGE_REL_MIPS_REFHI);
+  ECase(IMAGE_REL_MIPS_REFLO);
+  ECase(IMAGE_REL_MIPS_GPREL);
+  ECase(IMAGE_REL_MIPS_LITERAL);
+  ECase(IMAGE_REL_MIPS_SECTION);
+  ECase(IMAGE_REL_MIPS_SECREL);
+  ECase(IMAGE_REL_MIPS_SECRELLO);
+  ECase(IMAGE_REL_MIPS_SECRELHI);
+  ECase(IMAGE_REL_MIPS_JMPADDR16);
+  ECase(IMAGE_REL_MIPS_REFWORDNB);
+  ECase(IMAGE_REL_MIPS_PAIR);
+}
+
 void ScalarEnumerationTraits<COFF::RelocationTypesARM>::enumeration(
     IO &IO, COFF::RelocationTypesARM &Value) {
   ECase(IMAGE_REL_ARM_ABSOLUTE);
@@ -427,6 +446,10 @@ void MappingTraits<COFFYAML::Relocation>::mapping(IO &IO,
     MappingNormalization<NType<COFF::RelocationTypeAMD64>, uint16_t> NT(
         IO, Rel.Type);
     IO.mapRequired("Type", NT->Type);
+  } else if (H.Machine == COFF::IMAGE_FILE_MACHINE_R4000) {
+    MappingNormalization<NType<COFF::RelocationTypesMips>, uint16_t> NT(
+        IO, Rel.Type);
+    IO.mapRequired("Type", NT->Type);
   } else if (H.Machine == COFF::IMAGE_FILE_MACHINE_ARMNT) {
     MappingNormalization<NType<COFF::RelocationTypesARM>, uint16_t> NT(
         IO, Rel.Type);

llvm/test/tools/yaml2obj/COFF/basic-mips.yaml

@@ -0,0 +1,39 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj --file-headers --relocs %t | FileCheck %s
+# RUN: obj2yaml %t | FileCheck %s --check-prefix=ROUNDTRIP
+
+# CHECK: Format: COFF-MIPS
+# CHECK: Arch: mipsel
+# CHECK: Machine: IMAGE_FILE_MACHINE_R4000 (0x166)
+# CHECK: Relocations [
+# CHECK:  Section (1) .text {
+# CHECK:    0x4 IMAGE_REL_MIPS_JMPADDR main (0)
+# CHECK:  }
+# CHECK: ]
+
+# ROUNDTRIP:      Machine: IMAGE_FILE_MACHINE_R4000
+# ROUNDTRIP:      Relocations:
+# ROUNDTRIP-NEXT: - VirtualAddress: 4
+# ROUNDTRIP-NEXT:   SymbolName:     main
+# ROUNDTRIP-NEXT:   Type:           IMAGE_REL_MIPS_JMPADDR
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_R4000
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    VirtualSize:     12
+    SectionData:     000000000000000C00000000
+    Relocations:
+      - VirtualAddress:  4
+        SymbolName:      main
+        Type:            IMAGE_REL_MIPS_JMPADDR
+symbols:
+  - Name: main
+    Value: 0
+    SectionNumber: 1
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_NULL
+    StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+...