[Object] Implement relocation resolver for COFF ARM/ARM64

[mstorsjo]

Summary

This is primarily used for reading debug info from unrelocated object files, for handling addr and secrel relocations.

Also add testcases for the existing code for COFF on X86.

@JDevlieghere - I'm adding tests for this under tools/llvm-dwarfdump. Currently there's two subdirs, X86 and AArch64 there, while I'm adding four testcases (coff-i386, coff-x86_64, coff-arm and coff-arm64). Are you ok with them placed in the toplevel dir, or do you want a different structure for them?

[ruiu]

lib/Object/RelocationResolver.cpp

443 ↗

(On Diff #219290)

Is it OK to silently wrap-around an overflowed value? I wonder if we should report an error.

[mstorsjo]

lib/Object/RelocationResolver.cpp

443 ↗

(On Diff #219290)

Not sure if the base values will be in range where overflow might even be expected.

In any case, this is the exact same existing code matching resolveCOFFX86 and resolveCOFFX86_64 (see the context of the diff), just with different arch-specific relocation names.

[ruiu]

LGTM

lib/Object/RelocationResolver.cpp

443 ↗

(On Diff #219290)

Ah, OK. There precedents there in this file indeed.

[MaskRay]

lib/Object/RelocationResolver.cpp

443 ↗

(On Diff #219290)

On DWARF side, error reporting should be possible now after D63713 added Error *Err to DWARFDataExtractor::getRelocatedValue.

I'll take a stab at improving it. (In any case, this change should not be blocked by that change but I hope @mstorsjo can add test cases about relocation overflows when that is done)

[MaskRay]

lib/Object/RelocationResolver.cpp

443 ↗

(On Diff #219290)

D67343 [DebugInfo] Change object::RelocationResolver to return Expected<uint64_t>

llvm/trunk/lib/Object/RelocationResolver.cpp

case COFF::IMAGE_REL_AMD64_SECREL:
     return (S + A) & 0xFFFFFFFF;
   case COFF::IMAGE_REL_AMD64_ADDR64:
     return S + A;
   default:
     llvm_unreachable("Invalid relocation type");
   }
 }
 
+static bool supportsCOFFARM(uint64_t Type) {
+  switch (Type) {
+  case COFF::IMAGE_REL_ARM_SECREL:
+  case COFF::IMAGE_REL_ARM_ADDR32:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static uint64_t resolveCOFFARM(RelocationRef R, uint64_t S, uint64_t A) {
+  switch (R.getType()) {
+  case COFF::IMAGE_REL_ARM_SECREL:
+  case COFF::IMAGE_REL_ARM_ADDR32:
+    return (S + A) & 0xFFFFFFFF;
+  default:
+    llvm_unreachable("Invalid relocation type");
+  }
+}
+
+static bool supportsCOFFARM64(uint64_t Type) {
+  switch (Type) {
+  case COFF::IMAGE_REL_ARM64_SECREL:
+  case COFF::IMAGE_REL_ARM64_ADDR64:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static uint64_t resolveCOFFARM64(RelocationRef R, uint64_t S, uint64_t A) {
+  switch (R.getType()) {
+  case COFF::IMAGE_REL_ARM64_SECREL:
+    return (S + A) & 0xFFFFFFFF;
+  case COFF::IMAGE_REL_ARM64_ADDR64:
+    return S + A;
+  default:
+    llvm_unreachable("Invalid relocation type");
+  }
+}
+
 static bool supportsMachOX86_64(uint64_t Type) {
   return Type == MachO::X86_64_RELOC_UNSIGNED;
 }
 
 static uint64_t resolveMachOX86_64(RelocationRef R, uint64_t S, uint64_t A) {
   if (R.getType() == MachO::X86_64_RELOC_UNSIGNED)
     return S;
   llvm_unreachable("Invalid relocation type");
static uint64_t resolveWasm32(RelocationRef R, uint64_t S, uint64_t A) {
   default:
     llvm_unreachable("Invalid relocation type");
   }
 }
 
 std::pair<bool (*)(uint64_t), RelocationResolver>
 getRelocationResolver(const ObjectFile &Obj) {
   if (Obj.isCOFF()) {
-    if (Obj.getBytesInAddress() == 8)
+    switch (Obj.getArch()) {
+    case Triple::x86_64:
       return {supportsCOFFX86_64, resolveCOFFX86_64};
+    case Triple::x86:
       return {supportsCOFFX86, resolveCOFFX86};
+    case Triple::arm:
+    case Triple::thumb:
+      return {supportsCOFFARM, resolveCOFFARM};
+    case Triple::aarch64:
+      return {supportsCOFFARM64, resolveCOFFARM64};
+    default:
+      return {nullptr, nullptr};
+    }
   } else if (Obj.isELF()) {
     if (Obj.getBytesInAddress() == 8) {
       switch (Obj.getArch()) {
       case Triple::x86_64:
         return {supportsX86_64, resolveX86_64};
       case Triple::aarch64:
       case Triple::aarch64_be:
         return {supportsAArch64, resolveAArch64};

llvm/trunk/test/tools/llvm-dwarfdump/coff-arm.yaml

+# RUN: yaml2obj %s | llvm-dwarfdump - | FileCheck %s
+# CHECK:      DW_TAG_compile_unit
+# CHECK-NEXT:   DW_AT_producer ("producer string")
+# CHECK-NEXT:   DW_AT_language (DW_LANG_C99)
+# CHECK-NEXT:   DW_AT_name     ("test.c")
+# CHECK-NEXT:   DW_AT_comp_dir ("/path/to/src")
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARMNT
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_PURGEABLE, IMAGE_SCN_MEM_16BIT, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .data
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .bss
+    Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+    SizeOfRawData:   0
+  - Name:            .debug_str
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     70726F647563657220737472696E6700746573742E63002F706174682F746F2F73726300
+  - Name:            .debug_abbrev
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     011101250E1305030E1B0E000000
+  - Name:            .debug_info
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     170000000400000000000401000000000C00000000000000000000
+    Relocations:
+      - VirtualAddress:  6
+        SymbolName:      .debug_abbrev
+        Type:            IMAGE_REL_ARM_SECREL
+      - VirtualAddress:  12
+        SymbolName:      info_string0
+        Type:            IMAGE_REL_ARM_SECREL
+      - VirtualAddress:  18
+        SymbolName:      info_string1
+        Type:            IMAGE_REL_ARM_SECREL
+      - VirtualAddress:  22
+        SymbolName:      info_string2
+        Type:            IMAGE_REL_ARM_SECREL
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            .data
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
+  - Name:            .bss
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          3
+  - Name:            .debug_str
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        3440120581
+      Number:          4
+  - Name:            .debug_abbrev
+    Value:           0
+    SectionNumber:   5
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          14
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        2811829245
+      Number:          5
+  - Name:            .debug_info
+    Value:           0
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          27
+      NumberOfRelocations: 4
+      NumberOfLinenumbers: 0
+      CheckSum:        1535600857
+      Number:          6
+  - Name:            info_string0
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string1
+    Value:           16
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string2
+    Value:           23
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...

llvm/trunk/test/tools/llvm-dwarfdump/coff-arm64.yaml

+# RUN: yaml2obj %s | llvm-dwarfdump - | FileCheck %s
+# CHECK:      DW_TAG_compile_unit
+# CHECK-NEXT:   DW_AT_producer ("producer string")
+# CHECK-NEXT:   DW_AT_language (DW_LANG_C99)
+# CHECK-NEXT:   DW_AT_name     ("test.c")
+# CHECK-NEXT:   DW_AT_comp_dir ("/path/to/src")
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARM64
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .data
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .bss
+    Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+    SizeOfRawData:   0
+  - Name:            .debug_str
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     70726F647563657220737472696E6700746573742E63002F706174682F746F2F73726300
+  - Name:            .debug_abbrev
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     011101250E1305030E1B0E000000
+  - Name:            .debug_info
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     170000000400000000000401000000000C00000000000000000000
+    Relocations:
+      - VirtualAddress:  6
+        SymbolName:      .debug_abbrev
+        Type:            IMAGE_REL_ARM64_SECREL
+      - VirtualAddress:  12
+        SymbolName:      info_string0
+        Type:            IMAGE_REL_ARM64_SECREL
+      - VirtualAddress:  18
+        SymbolName:      info_string1
+        Type:            IMAGE_REL_ARM64_SECREL
+      - VirtualAddress:  22
+        SymbolName:      info_string2
+        Type:            IMAGE_REL_ARM64_SECREL
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            .data
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
+  - Name:            .bss
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          3
+  - Name:            .debug_str
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        3440120581
+      Number:          4
+  - Name:            .debug_abbrev
+    Value:           0
+    SectionNumber:   5
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          14
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        2811829245
+      Number:          5
+  - Name:            .debug_info
+    Value:           0
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          27
+      NumberOfRelocations: 4
+      NumberOfLinenumbers: 0
+      CheckSum:        1535600857
+      Number:          6
+  - Name:            info_string0
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string1
+    Value:           16
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string2
+    Value:           23
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...

llvm/trunk/test/tools/llvm-dwarfdump/coff-i386.yaml

+# RUN: yaml2obj %s | llvm-dwarfdump - | FileCheck %s
+# CHECK:      DW_TAG_compile_unit
+# CHECK-NEXT:   DW_AT_producer ("producer string")
+# CHECK-NEXT:   DW_AT_language (DW_LANG_C99)
+# CHECK-NEXT:   DW_AT_name     ("test.c")
+# CHECK-NEXT:   DW_AT_comp_dir ("/path/to/src")
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_I386
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .data
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .bss
+    Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+    SizeOfRawData:   0
+  - Name:            .debug_str
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     70726F647563657220737472696E6700746573742E63002F706174682F746F2F73726300
+  - Name:            .debug_abbrev
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     011101250E1305030E1B0E000000
+  - Name:            .debug_info
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     170000000400000000000401000000000C00000000000000000000
+    Relocations:
+      - VirtualAddress:  6
+        SymbolName:      .Lsection_abbrev
+        Type:            IMAGE_REL_I386_SECREL
+      - VirtualAddress:  12
+        SymbolName:      info_string0
+        Type:            IMAGE_REL_I386_SECREL
+      - VirtualAddress:  18
+        SymbolName:      info_string1
+        Type:            IMAGE_REL_I386_SECREL
+      - VirtualAddress:  22
+        SymbolName:      info_string2
+        Type:            IMAGE_REL_I386_SECREL
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            .data
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
+  - Name:            .bss
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          0
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          3
+  - Name:            .debug_str
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        3440120581
+      Number:          4
+  - Name:            .debug_abbrev
+    Value:           0
+    SectionNumber:   5
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          14
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        2811829245
+      Number:          5
+  - Name:            .debug_info
+    Value:           0
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          27
+      NumberOfRelocations: 4
+      NumberOfLinenumbers: 0
+      CheckSum:        1535600857
+      Number:          6
+  - Name:            info_string0
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string1
+    Value:           16
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            info_string2
+    Value:           23
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .Lsection_abbrev
+    Value:           0
+    SectionNumber:   5
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .Lsection_info
+    Value:           0
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .Lcu_begin0
+    Value:           0
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .Ldebug_info_end0
+    Value:           27
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .Ldebug_info_start0
+    Value:           4
+    SectionNumber:   6
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...

llvm/trunk/test/tools/llvm-dwarfdump/coff-x86_64.yaml

+# RUN: yaml2obj %s | llvm-dwarfdump - | FileCheck %s
+# CHECK:      DW_TAG_compile_unit
+# CHECK-NEXT:   DW_AT_producer ("producer string")
+# CHECK-NEXT:   DW_AT_language (DW_LANG_C99)
+# CHECK-NEXT:   DW_AT_name     ("test.c")
+# CHECK-NEXT:   DW_AT_comp_dir ("/path/to/src")
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .data
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+  - Name:            .bss
+    Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     ''
+    SizeOfRawData:   0
+  - Name:            .debug_str
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
+    Alignment:       1
+    SectionData:     70726F647563657220737472696E6700746573742E63002F706174682F746F2F73726300
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