Add verification for DW_AT_decl_file and DW_AT_call_file.

[clayborg]

Summary

LTO builds have been creating invalid DWARF and one of the errors was a file index that was out of bounds. "llvm-dwarfdump --verify" will check all file indexes for line tables already, but there are no checks for the validity of file indexes in attributes.

The verification will verify if there is a DW_AT_decl_file/DW_AT_call_file that:

• there is a line table for the compile unit
• the file index is valid
• the encoding is appropriate

Tests are added that test all of the above conditions.

[jhenderson]

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

548

Maybe best to make this not named after the version, e.g. IsZeroIndexed?

558

On first read, I found "by" to feel not quite the right word. Perhaps "with" would be better? (Not 100% sure either way though).

560

Here and below, from a quick glance, it doesn't look like most of the verifier error messages have a trailing full stop, so these probably shouldn't either.

llvm/test/tools/llvm-dwarfdump/X86/verify_attr_file_indexes.yaml

2

Nit: delete blank line at file start.

21

Rather than using mach-o, which has a lot of noise in its YAML, it might be worth switching to ELF. I think yaml2obj's ELF support is more-or-less sufficient now to achieve the desired goal. I think all you'd need to do is to use an ELF file header (you can find some simple examples in the yaml2obj tests), but keep the DWARF block the same.

There are probably ways to reduce the DWARF bit of the YAML too. @Higuoxing is actively working on improving this, so might be able to offer some tips, but I don't know how much could be done there yet.

llvm/test/tools/llvm-dwarfdump/X86/verify_file_encoding.yaml

19

Same comments as other test.

[Higuoxing]

llvm/test/tools/llvm-dwarfdump/X86/verify_attr_file_indexes.yaml

21

Yes, this YAML file is able to be reduced by replacing the Mach-O header with ELF header. I've tested it.

--- !ELF
FileHeader:
  Class:   ELFCLASS64
  Data:    ELFDATA2LSB
  Type:    ET_EXEC
  Machine: EM_X86_64
DWARF:
  debug_str:
    - ''
    - '/tmp/main.c'
    - main
    - inline1
  debug_abbrev:
    - Code:            0x0000000000000001
      Tag:             DW_TAG_compile_unit
      Children:        DW_CHILDREN_yes
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_language
          Form:            DW_FORM_data2
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_stmt_list
          Form:            DW_FORM_sec_offset
    - Code:            0x0000000000000002
      Tag:             DW_TAG_subprogram
      Children:        DW_CHILDREN_yes
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_high_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_decl_file
          Form:            DW_FORM_data1
        - Attribute:       DW_AT_call_line
          Form:            DW_FORM_data1
    - Code:            0x0000000000000003
      Tag:             DW_TAG_inlined_subroutine
      Children:        DW_CHILDREN_no
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_high_pc
          Form:            DW_FORM_data4
        - Attribute:       DW_AT_call_file
          Form:            DW_FORM_data1
        - Attribute:       DW_AT_call_line
          Form:            DW_FORM_data1
  debug_info:
    - Length:          0x0000000000000046
      Version:         4
      AbbrOffset:      0x0000000000000000
      AddrSize:        8
      Entries:
        - AbbrCode:        0x00000001
          Values:
            - Value:           0x0000000000000001
            - Value:           0x0000000000000002
            - Value:           0x0000000000000000
            - Value:           0x0000000000000000
        - AbbrCode:        0x00000002
          Values:
            - Value:           0x000000000000000D
            - Value:           0x0000000000001000
            - Value:           0x0000000000002000
            - Value:           0x0000000000000002
            - Value:           0x0000000000000005
        - AbbrCode:        0x00000003
          Values:
            - Value:           0x0000000000000012
            - Value:           0x0000000000001100
            - Value:           0x0000000000000100
            - Value:           0x0000000000000003
            - Value:           0x000000000000000A
        - AbbrCode:        0x00000000
          Values:          []
        - AbbrCode:        0x00000000
          Values:          []
  debug_line:
    - Length:          40
      Version:         2
      PrologueLength:  34
      MinInstLength:   1
      DefaultIsStmt:   1
      LineBase:        251
      LineRange:       14
      OpcodeBase:      13
      StandardOpcodeLengths: [ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 ]
      IncludeDirs:
        - '/tmp'
      Files:
        - Name:            main.c
          DirIdx:          1
          ModTime:         0
          Length:          0
      Opcodes:         []

There are probably ways to reduce the DWARF bit of the YAML too.

I would like not to reduce the DWARF for now since most of the fields are required.

llvm/test/tools/llvm-dwarfdump/X86/verify_file_encoding.yaml

19

We can use ELF YAML for this test as well.

--- !ELF
FileHeader:
  Class:   ELFCLASS64
  Data:    ELFDATA2LSB
  Type:    ET_EXEC
  Machine: EM_X86_64
DWARF:
  debug_str:
    - ''
    - '/tmp/main.c'
    - main
    - ''
    - inline1
  debug_abbrev:
    - Code:            0x0000000000000001
      Tag:             DW_TAG_compile_unit
      Children:        DW_CHILDREN_yes
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_language
          Form:            DW_FORM_data2
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
    - Code:            0x0000000000000002
      Tag:             DW_TAG_subprogram
      Children:        DW_CHILDREN_yes
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_high_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_decl_file
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_call_line
          Form:            DW_FORM_data1
    - Code:            0x0000000000000003
      Tag:             DW_TAG_inlined_subroutine
      Children:        DW_CHILDREN_no
      Attributes:
        - Attribute:       DW_AT_name
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_low_pc
          Form:            DW_FORM_addr
        - Attribute:       DW_AT_high_pc
          Form:            DW_FORM_data4
        - Attribute:       DW_AT_call_file
          Form:            DW_FORM_strp
        - Attribute:       DW_AT_call_line
          Form:            DW_FORM_data1
  debug_info:
    - Length:          0x0000000000000048
      Version:         4
      AbbrOffset:      0x0000000000000000
      AddrSize:        8
      Entries:
        - AbbrCode:        0x00000001
          Values:
            - Value:           0x0000000000000001
            - Value:           0x0000000000000002
            - Value:           0x0000000000000000
        - AbbrCode:        0x00000002
          Values:
            - Value:           0x000000000000000D
            - Value:           0x0000000000001000
            - Value:           0x0000000000002000
            - Value:           0x0000000000000012
            - Value:           0x0000000000000005
        - AbbrCode:        0x00000003
          Values:
            - Value:           0x0000000000000013
            - Value:           0x0000000000001100
            - Value:           0x0000000000000100
            - Value:           0x0000000000000012
            - Value:           0x000000000000000A
        - AbbrCode:        0x00000000
          Values:          []
        - AbbrCode:        0x00000000
          Values:          []

[Higuoxing]

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

82

I think uint64_t makes more sense here.

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

556

I think the brackets for else can be removed.

562

The brackets for else can be removed as well.

566

This break should be put into the bracket?

- } break;
+   break;
+ }

[clayborg]

Fixed inline comments:

• switched yaml files over to use ELF
• remove unneeded brackets
• renamed some variables

[clayborg]

Marked things as done.

[jhenderson]

Aside from the braces issue mentioned inline, LGTM.

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

556

My reading of recent updates to https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements is that if the if or else requires braces, the other half should too, so I think we actually want them here.

562

Same comment as above.

[Higuoxing]

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

556

Seems that I missed it. Sorry for the misdirection.

[clayborg]

Added else braces back.

[clayborg]

Anymore issues with this patch?

[jhenderson]

Not from me! LGTM again.

[aprantl]

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

88

What happens if Filenames.size() == 0? Can that happen in malformed DWARF input? Otherwise can we add an assert that it isn't zero?

Should it return an Optional<uint64_t>?

[clayborg]

Made DWARFDebugLine::Prologue::getLastValidFileIndex() and DWARFDebugLine::getLastValidFileIndex() return an Optional<uint64_t> and modified the error message for when a file index is out of range to specify the valid range, or specify that there are no files in the prologue file table. Added a test to cover this case as well.

[clayborg]

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

88

Yep, switched it over and added a test to cover this as well.

[jhenderson]

Latest update LGTM.

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

84

Do you actually need the llvm:: prefix here?

llvm/test/tools/llvm-dwarfdump/X86/verify_attr_file_indexes_no_files.yaml

19 ↗

(On Diff #283124)

Nit: add a blank line before the YAML.

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

struct Prologue {
 
     /// Get DWARF-version aware access to the file name entry at the provided
     /// index.
     const llvm::DWARFDebugLine::FileNameEntry &
     getFileNameEntry(uint64_t Index) const;
 
     bool hasFileAtIndex(uint64_t FileIndex) const;
 
+    uint32_t getLastValidFileIndex() const;
+
     bool
     getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
                        DILineInfoSpecifier::FileLineInfoKind Kind,
                        std::string &Result,
                        sys::path::Style Style = sys::path::Style::native) const;
 
     void clear();
     void dump(raw_ostream &OS, DIDumpOptions DumpOptions) const;
struct LineTable {
 
     bool lookupAddressRange(object::SectionedAddress Address, uint64_t Size,
                             std::vector<uint32_t> &Result) const;
 
     bool hasFileAtIndex(uint64_t FileIndex) const {
       return Prologue.hasFileAtIndex(FileIndex);
     }
 
+    uint32_t getLastValidFileIndex() const {
+      return Prologue.getLastValidFileIndex();
+    }
+
     /// Extracts filename by its index in filename table in prologue.
     /// In Dwarf 4, the files are 1-indexed and the current compilation file
     /// name is not represented in the list. In DWARF v5, the files are
     /// 0-indexed and the primary source file has the index 0.
     /// Returns true on success.
     bool getFileNameByIndex(uint64_t FileIndex, StringRef CompDir,
                             DILineInfoSpecifier::FileLineInfoKind Kind,
                             std::string &Result) const {

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
   uint16_t DwarfVersion = getVersion();
   assert(DwarfVersion != 0 &&
          "line table prologue has no dwarf version information");
   if (DwarfVersion >= 5)
     return FileIndex < FileNames.size();
   return FileIndex != 0 && FileIndex <= FileNames.size();
 }
 
+uint32_t DWARFDebugLine::Prologue::getLastValidFileIndex() const {
+  uint16_t DwarfVersion = getVersion();
+  assert(DwarfVersion != 0 &&
+         "line table prologue has no dwarf version information");
+  // In DWARF v5 the file names are 0-indexed.
+  if (DwarfVersion >= 5)
+    return FileNames.size() - 1;
+  return FileNames.size();
+}
+
 const llvm::DWARFDebugLine::FileNameEntry &
 DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
   uint16_t DwarfVersion = getVersion();
   assert(DwarfVersion != 0 &&
          "line table prologue has no dwarf version information");
   // In DWARF v5 the file names are 0-indexed.
   if (DwarfVersion >= 5)
     return FileNames[Index];

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
   case DW_AT_type: {
     DWARFDie TypeDie = Die.getAttributeValueAsReferencedDie(DW_AT_type);
     if (TypeDie && !isType(TypeDie.getTag())) {
       ReportError("DIE has " + AttributeString(Attr) +
                   " with incompatible tag " + TagString(TypeDie.getTag()));
     }
     break;
   }
+  case DW_AT_call_file:
+  case DW_AT_decl_file: {
+    if (auto FileIdx = AttrValue.Value.getAsUnsignedConstant()) {
+      DWARFUnit *U = Die.getDwarfUnit();
+      const auto *LT = U->getContext().getLineTableForUnit(U);
+      if (LT) {
+        if (!LT->hasFileAtIndex(*FileIdx)) {
+          bool IsZeroIndexed = LT->Prologue.getVersion() >= 5;
+          uint32_t LastFileIdx = LT->getLastValidFileIndex();
+          ReportError("DIE has " + AttributeString(Attr) +
+                      " with an invalid file index " +
+                      llvm::formatv("{0}", *FileIdx) + " (valid values are [" +
+                      (IsZeroIndexed ? "0-" : "1-") +
+                      llvm::formatv("{0}", LastFileIdx) + "])");
+        }
+      } else {
+        ReportError("DIE has " + AttributeString(Attr) +
+                    " that references a file with index " +
+                    llvm::formatv("{0}", *FileIdx) +
+                    " and the compile unit has no line table");
+      }
+    } else {
+      ReportError("DIE has " + AttributeString(Attr) +
+                  " with invalid encoding");
+    }
+    break;
+  }
   default:
     break;
   }
   return NumErrors;
 }
 
 unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
                                             DWARFAttribute &AttrValue) {

llvm/test/tools/llvm-dwarfdump/X86/verify_attr_file_indexes.yaml

+# RUN: yaml2obj %s | not llvm-dwarfdump --verify - | FileCheck %s --implicit-check-not=error:
+
+# CHECK:      error: DIE has DW_AT_decl_file with an invalid file index 2 (valid values are [1-1]){{[[:space:]]}}
+# CHECK-NEXT: 0x0000001e: DW_TAG_subprogram
+# CHECK-NEXT:               DW_AT_name        ("main")
+# CHECK-NEXT:               DW_AT_low_pc      (0x0000000000001000)
+# CHECK-NEXT:               DW_AT_high_pc     (0x0000000000002000)
+# CHECK-NEXT:               DW_AT_decl_file   (0x02)
+# CHECK-NEXT:               DW_AT_call_line   (5){{[[:space:]]}}
+# CHECK-NEXT: error: DIE has DW_AT_call_file with an invalid file index 3 (valid values are [1-1]){{[[:space:]]}}
+# CHECK-NEXT: 0x00000035: DW_TAG_inlined_subroutine
+# CHECK-NEXT:               DW_AT_name        ("inline1")
+# CHECK-NEXT:               DW_AT_low_pc      (0x0000000000001100)
+# CHECK-NEXT:               DW_AT_high_pc     (0x0000000000001200)
+# CHECK-NEXT:               DW_AT_call_file   (0x03)
+# CHECK-NEXT:               DW_AT_call_line   (10){{[[:space:]]}}
+
+# CHECK:      Errors detected.
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+DWARF:
+  debug_str:
+    - ''
+    - '/tmp/main.c'
+    - main
+    - inline1
+  debug_abbrev:
+    - Code:            0x0000000000000001
+      Tag:             DW_TAG_compile_unit
+      Children:        DW_CHILDREN_yes
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_language
+          Form:            DW_FORM_data2
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_stmt_list
+          Form:            DW_FORM_sec_offset
+    - Code:            0x0000000000000002
+      Tag:             DW_TAG_subprogram
+      Children:        DW_CHILDREN_yes
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_high_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_decl_file
+          Form:            DW_FORM_data1
+        - Attribute:       DW_AT_call_line
+          Form:            DW_FORM_data1
+    - Code:            0x0000000000000003
+      Tag:             DW_TAG_inlined_subroutine
+      Children:        DW_CHILDREN_no
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_high_pc
+          Form:            DW_FORM_data4
+        - Attribute:       DW_AT_call_file
+          Form:            DW_FORM_data1
+        - Attribute:       DW_AT_call_line
+          Form:            DW_FORM_data1
+  debug_info:
+    - Length:          0x0000000000000046
+      Version:         4
+      AbbrOffset:      0x0000000000000000
+      AddrSize:        8
+      Entries:
+        - AbbrCode:        0x00000001
+          Values:
+            - Value:           0x0000000000000001
+            - Value:           0x0000000000000002
+            - Value:           0x0000000000000000
+            - Value:           0x0000000000000000
+        - AbbrCode:        0x00000002
+          Values:
+            - Value:           0x000000000000000D
+            - Value:           0x0000000000001000
+            - Value:           0x0000000000002000
+            - Value:           0x0000000000000002
+            - Value:           0x0000000000000005
+        - AbbrCode:        0x00000003
+          Values:
+            - Value:           0x0000000000000012
+            - Value:           0x0000000000001100
+            - Value:           0x0000000000000100
+            - Value:           0x0000000000000003
+            - Value:           0x000000000000000A
+        - AbbrCode:        0x00000000
+          Values:          []
+        - AbbrCode:        0x00000000
+          Values:          []
+  debug_line:
+    - Length:          40
+      Version:         2
+      PrologueLength:  34
+      MinInstLength:   1
+      DefaultIsStmt:   1
+      LineBase:        251
+      LineRange:       14
+      OpcodeBase:      13
+      StandardOpcodeLengths: [ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 ]
+      IncludeDirs:
+        - '/tmp'
+      Files:
+        - Name:            main.c
+          DirIdx:          1
+          ModTime:         0
+          Length:          0
+      Opcodes:         []
+...

llvm/test/tools/llvm-dwarfdump/X86/verify_debug_info.s

 # RUN: llvm-mc %s -filetype obj -triple x86_64-apple-darwin -o - \
 # RUN: | not llvm-dwarfdump -v -verify - \
 # RUN: | FileCheck %s
 
 # CHECK: error: DIE has invalid DW_AT_stmt_list encoding:{{[[:space:]]}}
 # CHECK-NEXT: 0x0000000c: DW_TAG_compile_unit [1] *
 # CHECK-NEXT: DW_AT_producer [DW_FORM_strp] ( .debug_str[0x00000000] = "clang version 5.0.0 (trunk 308185) (llvm/trunk 308186)")
 # CHECK-NEXT: DW_AT_language [DW_FORM_data2]  (DW_LANG_C99)
 # CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000037] = "basic.c")
 # CHECK-NEXT: DW_AT_stmt_list [DW_FORM_block4]
 # CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x0000003f] = "/Users/sgravani/Development/tests")
 # CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
 # CHECK-NEXT: DW_AT_high_pc [DW_FORM_data4] (0x00000016){{[[:space:]]}}
+# CHECK-NEXT: error: DIE has DW_AT_decl_file that references a file with index 1 and the compile unit has no line table{{[[:space:]]}}
+# CHECK-NEXT: 0x0000002b: DW_TAG_subprogram [2] *
+# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
+# CHECK-NEXT: DW_AT_high_pc [DW_FORM_data4] (0x00000016)
+# CHECK-NEXT: DW_AT_frame_base [DW_FORM_exprloc]  (DW_OP_reg6)
+# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000061] = "main")
+# CHECK-NEXT: DW_AT_decl_file [DW_FORM_data1] (0x01)
+# CHECK-NEXT: DW_AT_decl_line [DW_FORM_data1] (1)
+# CHECK-NEXT: DW_AT_prototyped [DW_FORM_flag_present] (true)
+# CHECK-NEXT: DW_AT_type [DW_FORM_ref4] (cu + 0x0052 => {0x00000052} "")
+# CHECK-NEXT: DW_AT_external [DW_FORM_flag_present] (true){{[[:space:]]}}
 # CHECK-NEXT: error: DIE has DW_AT_type with incompatible tag DW_TAG_null{{[[:space:]]}}
 # CHECK-NEXT: 0x0000002b: DW_TAG_subprogram [2] *
 # CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 # CHECK-NEXT: DW_AT_high_pc [DW_FORM_data4]     (0x00000016)
 # CHECK-NEXT: DW_AT_frame_base [DW_FORM_exprloc]        (DW_OP_reg6)
 # CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x00000061] = "main")
 # CHECK-NEXT: DW_AT_decl_file [DW_FORM_data1]   (0x01)
 # CHECK-NEXT: DW_AT_decl_line [DW_FORM_data1]   (1)
 # CHECK-NEXT: DW_AT_prototyped [DW_FORM_flag_present]   (true)
 # CHECK-NEXT: DW_AT_type [DW_FORM_ref4] (cu + 0x0052 => {0x00000052} "")
 # CHECK-NEXT: DW_AT_external [DW_FORM_flag_present]     (true){{[[:space:]]}}
+# CHECK-NEXT: error: DIE has DW_AT_decl_file that references a file with index 1 and the compile unit has no line table{{[[:space:]]}}
+# CHECK-NEXT: 0x00000044: DW_TAG_variable [3]
+# CHECK-NEXT: DW_AT_location [DW_FORM_exprloc]  (DW_OP_fbreg -8)
+# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000006a] = "a")
+# CHECK-NEXT: DW_AT_decl_file [DW_FORM_data1] (0x01)
+# CHECK-NEXT: DW_AT_decl_line [DW_FORM_data1] (2)
+# CHECK-NEXT: DW_AT_use_location [DW_FORM_ref4] (cu + 0x0053 => {0x00000053}){{[[:space:]]}}
 # CHECK-NEXT: error: Compilation unit root DIE is not a unit DIE: DW_TAG_null.
 # CHECK-NEXT: error: Compilation unit type (DW_UT_compile) and root DIE (DW_TAG_null) do not match.
 # CHECK-NEXT: error: Units[2] - start offset: 0x00000068
 # CHECK-NEXT: note: The length for this unit is too large for the .debug_info provided.
 # CHECK-NEXT: note: The unit type encoding is not valid.
 
 
   .section  __TEXT,__text,regular,pure_instructions

llvm/test/tools/llvm-dwarfdump/X86/verify_file_encoding.yaml

+# RUN: yaml2obj %s | not llvm-dwarfdump --verify - | FileCheck %s --implicit-check-not=error:
+
+# CHECK:      error: DIE has DW_AT_decl_file with invalid encoding{{[[:space:]]}}
+# CHECK-NEXT: 0x0000001a: DW_TAG_subprogram
+# CHECK-NEXT:               DW_AT_name        ("main")
+# CHECK-NEXT:               DW_AT_low_pc      (0x0000000000001000)
+# CHECK-NEXT:               DW_AT_high_pc     (0x0000000000002000)
+# CHECK-NEXT:               DW_AT_decl_file   ("")
+# CHECK-NEXT:               DW_AT_call_line   (5){{[[:space:]]}}
+# CHECK-NEXT: error: DIE has DW_AT_call_file with invalid encoding{{[[:space:]]}}
+# CHECK-NEXT: 0x00000034: DW_TAG_inlined_subroutine
+# CHECK-NEXT:               DW_AT_name        ("inline1")
+# CHECK-NEXT:               DW_AT_low_pc      (0x0000000000001100)
+# CHECK-NEXT:               DW_AT_high_pc     (0x0000000000001200)
+# CHECK-NEXT:               DW_AT_call_file   ("")
+# CHECK-NEXT:               DW_AT_call_line   (10){{[[:space:]]}}
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+DWARF:
+  debug_str:
+    - ''
+    - '/tmp/main.c'
+    - main
+    - ''
+    - inline1
+  debug_abbrev:
+    - Code:            0x0000000000000001
+      Tag:             DW_TAG_compile_unit
+      Children:        DW_CHILDREN_yes
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_language
+          Form:            DW_FORM_data2
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+    - Code:            0x0000000000000002
+      Tag:             DW_TAG_subprogram
+      Children:        DW_CHILDREN_yes
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_high_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_decl_file
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_call_line
+          Form:            DW_FORM_data1
+    - Code:            0x0000000000000003
+      Tag:             DW_TAG_inlined_subroutine
+      Children:        DW_CHILDREN_no
+      Attributes:
+        - Attribute:       DW_AT_name
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_low_pc
+          Form:            DW_FORM_addr
+        - Attribute:       DW_AT_high_pc
+          Form:            DW_FORM_data4
+        - Attribute:       DW_AT_call_file
+          Form:            DW_FORM_strp
+        - Attribute:       DW_AT_call_line
+          Form:            DW_FORM_data1
+  debug_info:
+    - Length:          0x0000000000000048
+      Version:         4
+      AbbrOffset:      0x0000000000000000
+      AddrSize:        8
+      Entries:
+        - AbbrCode:        0x00000001
+          Values:
+            - Value:           0x0000000000000001
+            - Value:           0x0000000000000002
+            - Value:           0x0000000000000000
+        - AbbrCode:        0x00000002
+          Values:
+            - Value:           0x000000000000000D
+            - Value:           0x0000000000001000
+            - Value:           0x0000000000002000
+            - Value:           0x0000000000000012
+            - Value:           0x0000000000000005
+        - AbbrCode:        0x00000003
+          Values:
+            - Value:           0x0000000000000013
+            - Value:           0x0000000000001100
+            - Value:           0x0000000000000100
+            - Value:           0x0000000000000012
+            - Value:           0x000000000000000A
+        - AbbrCode:        0x00000000
+          Values:          []
+        - AbbrCode:        0x00000000
+          Values:          []
+...