forked from OSchip/llvm-project
[ELF] - Also use DW_AT_linkage_name when gathering information about variables for error messages.
Currently, when LLD do a lookup for variables location, it uses DW_AT_name attribute.
That is not always enough.
Imagine code:
namespace A {
int bar = 0;
}
namespace Z {
int bar = 1;
}
int hoho;
In this case there are 3 variables and their debug attributes are following:
A::bar has: DW_AT_name [DW_FORM_string] ("bar") DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x00000006] = "_ZN1A3barE")
Z::bar has: DW_AT_name [DW_FORM_string] ("bar") DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x0000003f] = "_ZN1Z3barE")
hoho has: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000004a] = "hoho") and has NO DW_AT_linkage_name attribute. Because it would be
the same as DW_AT_name and DWARF producers avoids emiting excessive data.
Hence LLD should also use DW_AT_linkage_name when it is available.
(currently, LLD fails to report location correctly because thinks that A::bar and Z::bar are the same things)
Differential revision: https://reviews.llvm.org/D47373
llvm-svn: 333880
This commit is contained in:
George Rimar
parent
43e4367961
commit
64091d5626
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@ -167,10 +167,15 @@ template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
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// Get the line number on which the variable is declared.
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unsigned Line = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_line), 0);
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// Get the name of the variable and add the collected information to
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// VariableLoc. Usually Name is non-empty, but it can be empty if the
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// Here we want to take the variable name to add it into VariableLoc.
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// Variable can have regular and linkage name associated. At first, we try
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// to get linkage name as it can be different, for example when we have
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// two variables in different namespaces of the same object. Use common
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// name otherwise, but handle the case when it also absent in case if the
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// input object file lacks some debug info.
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StringRef Name = dwarf::toString(Die.find(dwarf::DW_AT_name), "");
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StringRef Name =
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dwarf::toString(Die.find(dwarf::DW_AT_linkage_name),
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dwarf::toString(Die.find(dwarf::DW_AT_name), ""));
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if (!Name.empty())
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VariableLoc.insert({Name, {LT, File, Line}});
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}
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@ -0,0 +1,193 @@
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# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
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# RUN: llvm-dwarfdump %t.o | FileCheck -check-prefix=INPUT %s
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# RUN: not ld.lld %t.o %t.o -o %t 2>&1 | FileCheck %s
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# INPUT: DW_TAG_variable
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# INPUT-NEXT: DW_AT_name ("bar")
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# INPUT-NEXT: DW_AT_type (0x0000003d "int")
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# INPUT-NEXT: DW_AT_external (true)
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# INPUT-NEXT: DW_AT_decl_file ("/path\1.cpp")
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# INPUT-NEXT: DW_AT_decl_line (2)
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# INPUT-NEXT: DW_AT_location (DW_OP_addr 0x0)
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# INPUT-NEXT: DW_AT_linkage_name ("_ZN1A3barE")
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# INPUT: DW_TAG_variable
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# INPUT-NEXT: DW_AT_name ("bar")
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# INPUT-NEXT: DW_AT_type (0x0000003d "int")
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# INPUT-NEXT: DW_AT_external (true)
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# INPUT-NEXT: DW_AT_decl_file ("/path\1.cpp")
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# INPUT-NEXT: DW_AT_decl_line (6)
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# INPUT-NEXT: DW_AT_location (DW_OP_addr 0x0)
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# INPUT-NEXT: DW_AT_linkage_name ("_ZN1Z3barE")
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## Check we can report the locations of 2 different "bar" variables.
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# CHECK: duplicate symbol: A::bar
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# CHECK-NEXT: >>> defined at 1.cpp:2
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# CHECK-NEXT: >>> {{.*}}:(A::bar)
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# CHECK-NEXT: >>> defined at 1.cpp:2
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# CHECK-NEXT: >>> {{.*}}:(.bss+0x0)
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# CHECK: duplicate symbol: Z::bar
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# CHECK-NEXT: >>> defined at 1.cpp:6
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# CHECK-NEXT: >>> {{.*}}:(Z::bar)
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# CHECK-NEXT: >>> defined at 1.cpp:6
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# CHECK-NEXT: >>> {{.*}}:(.data+0x0)
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# Used reduced output from following code and clang version 7.0.0 (trunk 332701)
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# to produce this input file:
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# Source (1.cpp):
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# namespace A {
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# int bar;
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# }
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#
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# namespace Z {
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# int bar;
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# }
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# Invocation: clang-7 -g -S 1.cpp
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.text
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.file "1.cpp"
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.file 1 "/path" "1.cpp"
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.type _ZN1A3barE,@object
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.bss
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.globl _ZN1A3barE
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_ZN1A3barE:
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.long 0
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.size _ZN1A3barE, 4
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.type _ZN1Z3barE,@object
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.data
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.globl _ZN1Z3barE
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_ZN1Z3barE:
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.long 1
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.size _ZN1Z3barE, 4
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.section .debug_str,"MS",@progbits,1
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.Linfo_string0:
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.asciz "clang version 7.0.0 (trunk 332701)" # string offset=0
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.Linfo_string1:
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.asciz "1.cpp" # string offset=35
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.Linfo_string2:
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.asciz "/path" # string offset=41
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.Linfo_string3:
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.asciz "A" # string offset=87
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.Linfo_string4:
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.asciz "bar" # string offset=89
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.Linfo_string5:
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.asciz "int" # string offset=93
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.Linfo_string6:
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.asciz "_ZN1A3barE" # string offset=97
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.Linfo_string7:
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.asciz "Z" # string offset=108
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.Linfo_string8:
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.asciz "_ZN1Z3barE" # string offset=110
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.section .debug_abbrev,"",@progbits
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.byte 1 # Abbreviation Code
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.byte 17 # DW_TAG_compile_unit
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.byte 1 # DW_CHILDREN_yes
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.byte 37 # DW_AT_producer
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.byte 14 # DW_FORM_strp
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.byte 19 # DW_AT_language
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.byte 5 # DW_FORM_data2
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.byte 3 # DW_AT_name
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.byte 14 # DW_FORM_strp
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.byte 16 # DW_AT_stmt_list
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.byte 23 # DW_FORM_sec_offset
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.byte 27 # DW_AT_comp_dir
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.byte 14 # DW_FORM_strp
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.ascii "\264B" # DW_AT_GNU_pubnames
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.byte 25 # DW_FORM_flag_present
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 2 # Abbreviation Code
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.byte 57 # DW_TAG_namespace
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.byte 1 # DW_CHILDREN_yes
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.byte 3 # DW_AT_name
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.byte 14 # DW_FORM_strp
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 3 # Abbreviation Code
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.byte 52 # DW_TAG_variable
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.byte 0 # DW_CHILDREN_no
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.byte 3 # DW_AT_name
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.byte 14 # DW_FORM_strp
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.byte 73 # DW_AT_type
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.byte 19 # DW_FORM_ref4
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.byte 63 # DW_AT_external
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.byte 25 # DW_FORM_flag_present
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.byte 58 # DW_AT_decl_file
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.byte 11 # DW_FORM_data1
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.byte 59 # DW_AT_decl_line
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.byte 11 # DW_FORM_data1
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.byte 2 # DW_AT_location
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.byte 24 # DW_FORM_exprloc
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.byte 110 # DW_AT_linkage_name
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.byte 14 # DW_FORM_strp
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 4 # Abbreviation Code
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.byte 36 # DW_TAG_base_type
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.byte 0 # DW_CHILDREN_no
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.byte 3 # DW_AT_name
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.byte 14 # DW_FORM_strp
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.byte 62 # DW_AT_encoding
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.byte 11 # DW_FORM_data1
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.byte 11 # DW_AT_byte_size
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.byte 11 # DW_FORM_data1
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 0 # EOM(3)
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.section .debug_info,"",@progbits
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.long 96 # Length of Unit
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.short 4 # DWARF version number
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.long .debug_abbrev # Offset Into Abbrev. Section
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.byte 8 # Address Size (in bytes)
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.byte 1 # Abbrev [1] 0xb:0x59 DW_TAG_compile_unit
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.long .Linfo_string0 # DW_AT_producer
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.short 4 # DW_AT_language
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.long .Linfo_string1 # DW_AT_name
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.long 0 # DW_AT_stmt_list
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.long .Linfo_string2 # DW_AT_comp_dir
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# DW_AT_GNU_pubnames
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.byte 2 # Abbrev [2] 0x1e:0x1f DW_TAG_namespace
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.long .Linfo_string3 # DW_AT_name
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.byte 3 # Abbrev [3] 0x23:0x19 DW_TAG_variable
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.long .Linfo_string4 # DW_AT_name
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.long 61 # DW_AT_type
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# DW_AT_external
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.byte 1 # DW_AT_decl_file
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.byte 2 # DW_AT_decl_line
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.byte 9 # DW_AT_location
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.byte 3
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.quad _ZN1A3barE
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.long .Linfo_string6 # DW_AT_linkage_name
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.byte 0 # End Of Children Mark
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.byte 4 # Abbrev [4] 0x3d:0x7 DW_TAG_base_type
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.long .Linfo_string5 # DW_AT_name
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.byte 5 # DW_AT_encoding
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.byte 4 # DW_AT_byte_size
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.byte 2 # Abbrev [2] 0x44:0x1f DW_TAG_namespace
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.long .Linfo_string7 # DW_AT_name
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.byte 3 # Abbrev [3] 0x49:0x19 DW_TAG_variable
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.long .Linfo_string4 # DW_AT_name
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.long 61 # DW_AT_type
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# DW_AT_external
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.byte 1 # DW_AT_decl_file
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.byte 6 # DW_AT_decl_line
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.byte 9 # DW_AT_location
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.byte 3
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.quad _ZN1Z3barE
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.long .Linfo_string8 # DW_AT_linkage_name
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.byte 0 # End Of Children Mark
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.byte 0 # End Of Children Mark
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