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Fix a bug where an error was emitted for GCC union types. (#159401)
GCC doesn't add DW_AT_data_member_location attributes to the DW_TAG_member children of DW_TAG_union_type types. An error was being emitted incorrectly for these cases fr om the DWARFASTParserClang. This fixes that issue and adds a test.
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‎lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3142,7 +3142,11 @@ void DWARFASTParserClang::ParseSingleMember(
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uint64_t parent_byte_size =
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parent_die.GetAttributeValueAsUnsigned(DW_AT_byte_size, UINT64_MAX);
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3145-
if (attrs.member_byte_offset >= parent_byte_size) {
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// If the attrs.member_byte_offset is still set to UINT32_MAX this means
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// that the DW_TAG_member didn't have a DW_AT_data_member_location, so
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// don't emit an error if this is the case.
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if (attrs.member_byte_offset != UINT32_MAX &&
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attrs.member_byte_offset >= parent_byte_size) {
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if (member_array_size != 1 &&
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(member_array_size != 0 ||
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attrs.member_byte_offset > parent_byte_size)) {

‎lldb/test/Shell/SymbolFile/DWARF/union-types-no-member-location.yaml‎

Lines changed: 182 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,182 @@
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# This test produces DWARF that contains a union type whose DW_TAG_member does
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# not have a DW_AT_data_member_location set to zero. This is how GCC emits
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# debug information for unions. There was code in the DWARFASTParserClang that
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# was emitting an invalid error in this case. This test verifies that this
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# error does not get emitted.
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#
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# 0x0000000b: DW_TAG_compile_unit
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# DW_AT_name ("main.cpp")
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# DW_AT_language (DW_LANG_C)
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#
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# 0x00000011: DW_TAG_base_type
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# DW_AT_name ("int")
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# DW_AT_encoding (DW_ATE_signed_char)
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# DW_AT_byte_size (0x04)
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#
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# 0x00000018: DW_TAG_base_type
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# DW_AT_name ("__ARRAY_SIZE_TYPE__")
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# DW_AT_encoding (DW_ATE_unsigned)
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# DW_AT_byte_size (0x08)
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#
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# 0x0000001f: DW_TAG_array_type
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# DW_AT_type (0x00000011 "int")
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#
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# 0x00000024: DW_TAG_subrange_type
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# DW_AT_type (0x00000018 "__ARRAY_SIZE_TYPE__")
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# DW_AT_count (0x20)
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#
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# 0x0000002a: NULL
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#
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# 0x0000002b: DW_TAG_union_type
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# DW_AT_name ("UnionType")
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# DW_AT_byte_size (0x20)
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#
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# 0x00000031: DW_TAG_member
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# DW_AT_name ("array")
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# DW_AT_type (0x0000001f "int[32]")
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#
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# 0x0000003a: NULL
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#
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# 0x0000003b: DW_TAG_subprogram
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# DW_AT_low_pc (0x0000000000001000)
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# DW_AT_high_pc (0x0000000000001050)
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# DW_AT_name ("foo")
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# DW_AT_type (0x00000031 "array")
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#
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# 0x00000054: NULL
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# RUN: yaml2obj %s > %t
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# RUN: lldb-test symbols --name=UnionType --find=type %t > %t.stdout
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# RUN: cat %t.stdout | FileCheck --check-prefix=STDOUT %s
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# RUN: lldb-test symbols --name=UnionType --find=type %t 2> %t.stderr
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# RUN: cat %t.stderr | FileCheck --allow-empty --check-prefix=STDERR %s
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# STDOUT: Found 1 types:
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# STDOUT: 0x{{[0-9a-fA-F]+}}: Type{0x0000002b} , name = "UnionType", size = 32, compiler_type = 0x{{[0-9a-fA-F]+}} union UnionType {
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# STDERR-NOT: error: union-types-no-member-location.yaml.tmp 0x00000031: DW_TAG_member 'array' refers to type 0x000000000000001f which extends beyond the bounds of 0x0000002b
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_X86_64
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DWARF:
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debug_str:
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- ''
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- main.cpp
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- int
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- __ARRAY_SIZE_TYPE__
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- UnionType
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- array
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debug_abbrev:
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- ID: 0
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Table:
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- Code: 0x1
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Tag: DW_TAG_compile_unit
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Children: DW_CHILDREN_yes
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Attributes:
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- Attribute: DW_AT_name
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Form: DW_FORM_strp
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- Attribute: DW_AT_language
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Form: DW_FORM_udata
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- Code: 0x2
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Tag: DW_TAG_base_type
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Children: DW_CHILDREN_no
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Attributes:
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- Attribute: DW_AT_name
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Form: DW_FORM_strp
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- Attribute: DW_AT_encoding
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Form: DW_FORM_data1
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- Attribute: DW_AT_byte_size
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Form: DW_FORM_data1
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- Code: 0x3
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Tag: DW_TAG_array_type
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Children: DW_CHILDREN_yes
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Attributes:
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- Attribute: DW_AT_type
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Form: DW_FORM_ref4
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- Code: 0x4
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Tag: DW_TAG_subrange_type
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Children: DW_CHILDREN_no
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Attributes:
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- Attribute: DW_AT_type
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Form: DW_FORM_ref4
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- Attribute: DW_AT_count
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Form: DW_FORM_data1
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- Code: 0x5
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Tag: DW_TAG_union_type
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Children: DW_CHILDREN_yes
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Attributes:
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- Attribute: DW_AT_name
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Form: DW_FORM_strp
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- Attribute: DW_AT_byte_size
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Form: DW_FORM_data1
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- Code: 0x6
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Tag: DW_TAG_member
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Children: DW_CHILDREN_no
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Attributes:
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- Attribute: DW_AT_name
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Form: DW_FORM_strp
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- Attribute: DW_AT_type
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Form: DW_FORM_ref4
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- Code: 0x7
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Tag: DW_TAG_subprogram
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Children: DW_CHILDREN_no
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Attributes:
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- Attribute: DW_AT_low_pc
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Form: DW_FORM_addr
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- Attribute: DW_AT_high_pc
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Form: DW_FORM_addr
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- Attribute: DW_AT_name
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Form: DW_FORM_string
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- Attribute: DW_AT_type
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Form: DW_FORM_ref4
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debug_info:
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- Length: 0x51
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Version: 4
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AbbrevTableID: 0
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AbbrOffset: 0x0
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AddrSize: 8
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Entries:
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- AbbrCode: 0x1
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Values:
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- Value: 0x1
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- Value: 0x2
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- AbbrCode: 0x2
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Values:
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- Value: 0xA
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- Value: 0x6
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- Value: 0x4
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- AbbrCode: 0x2
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Values:
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- Value: 0xE
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- Value: 0x7
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- Value: 0x8
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- AbbrCode: 0x3
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Values:
159+
- Value: 0x11
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- AbbrCode: 0x4
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Values:
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- Value: 0x18
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- Value: 0x20
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- AbbrCode: 0x0
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- AbbrCode: 0x5
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Values:
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- Value: 0x22
168+
- Value: 0x20
169+
- AbbrCode: 0x6
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Values:
171+
- Value: 0x2C
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- Value: 0x1F
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- AbbrCode: 0x0
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- AbbrCode: 0x7
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Values:
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- Value: 0x1000
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- Value: 0x1050
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- Value: 0xDEADBEEFDEADBEEF
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CStr: foo
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- Value: 0x31
181+
- AbbrCode: 0x0
182+
...

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