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George Rimar
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[LLD][ELF] - Improve the DWARF v5 suport for building .gdb_index.
Now LLD might build the broken/incomplete .gdb_index when some DWARF v5 sections (like .debug_rnglists and .debug_addr) are used. Particularly, for the case above, we emit an empty address area. A test case is provided and patch fixes the issue. Differential revision: https://reviews.llvm.org/D55109 llvm-svn: 348119
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lines changed

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‎lld/ELF/DWARF.cpp

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -33,10 +33,12 @@ template <class ELFT> LLDDwarfObj<ELFT>::LLDDwarfObj(ObjFile<ELFT> *Obj) {
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if (LLDDWARFSection *M =
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StringSwitch<LLDDWARFSection *>(Sec->Name)
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.Case(".debug_addr", &AddrSection)
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.Case(".debug_gnu_pubnames", &GnuPubNamesSection)
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.Case(".debug_gnu_pubtypes", &GnuPubTypesSection)
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.Case(".debug_info", &InfoSection)
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.Case(".debug_ranges", &RangeSection)
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.Case(".debug_rnglists", &RngListsSection)
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.Case(".debug_line", &LineSection)
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.Default(nullptr)) {
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M->Data = toStringRef(Sec->data());

‎lld/ELF/DWARF.h

Lines changed: 10 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -37,10 +37,18 @@ template <class ELFT> class LLDDwarfObj final : public llvm::DWARFObject {
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return RangeSection;
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}
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const llvm::DWARFSection &getRnglistsSection() const override {
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return RngListsSection;
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}
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const llvm::DWARFSection &getLineSection() const override {
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return LineSection;
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}
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const llvm::DWARFSection &getAddrSection() const override {
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return AddrSection;
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}
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const llvm::DWARFSection &getGnuPubNamesSection() const override {
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return GnuPubNamesSection;
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}
@@ -71,8 +79,9 @@ template <class ELFT> class LLDDwarfObj final : public llvm::DWARFObject {
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LLDDWARFSection GnuPubTypesSection;
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LLDDWARFSection InfoSection;
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LLDDWARFSection RangeSection;
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LLDDWARFSection RngListsSection;
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LLDDWARFSection LineSection;
75-
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LLDDWARFSection AddrSection;
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StringRef AbbrevSection;
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StringRef StrSection;
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StringRef LineStringSection;

‎lld/test/ELF/gdb-index-rng-lists.s

Lines changed: 202 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,202 @@
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# REQUIRES: x86
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# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
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# RUN: ld.lld --gdb-index %t1.o -o %t
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# RUN: llvm-dwarfdump -gdb-index %t | FileCheck %s
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## The code contains DWARF v5 sections .debug_rnglists and .debug_addr.
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## Check we are able to build the correct address
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## area using address range lists.
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# CHECK: .gdb_index contents:
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# CHECK: Address area offset = 0x28, has 2 entries:
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# CHECK-NEXT: Low/High address = [0x201000, 0x201001) (Size: 0x1), CU id = 0
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# CHECK-NEXT: Low/High address = [0x201001, 0x201003) (Size: 0x2), CU id = 0
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.text
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.section .text._Z3zedv,"ax",@progbits
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.Lfunc_begin0:
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retq
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.Lfunc_end0:
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.section .text.main,"ax",@progbits
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.Lfunc_begin1:
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retq
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retq
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.Lfunc_end1:
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.section .debug_str_offsets,"",@progbits
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.long 32
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.short 5
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.short 0
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.Lstr_offsets_base0:
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.long .Linfo_string0
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.long .Linfo_string0
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.long .Linfo_string0
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.long .Linfo_string0
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.long .Linfo_string0
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.long .Linfo_string0
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.long .Linfo_string0
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.section .debug_str,"MS",@progbits,1
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.Linfo_string0:
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.asciz "stub"
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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 37 # DW_FORM_strx1
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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 37 # DW_FORM_strx1
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.byte 114 # DW_AT_str_offsets_base
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.byte 23 # DW_FORM_sec_offset
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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 37 # DW_FORM_strx1
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.byte 115 # DW_AT_addr_base
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.byte 23 # DW_FORM_sec_offset
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.byte 17 # DW_AT_low_pc
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.byte 1 # DW_FORM_addr
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.byte 85 # DW_AT_ranges
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.byte 35 # DW_FORM_rnglistx
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.byte 116 # DW_AT_rnglists_base
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.byte 23 # DW_FORM_sec_offset
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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 46 # DW_TAG_subprogram
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.byte 0 # DW_CHILDREN_no
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.byte 17 # DW_AT_low_pc
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.byte 27 # DW_FORM_addrx
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.byte 18 # DW_AT_high_pc
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.byte 6 # DW_FORM_data4
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.byte 64 # DW_AT_frame_base
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.byte 24 # DW_FORM_exprloc
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.byte 110 # DW_AT_linkage_name
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.byte 37 # DW_FORM_strx1
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.byte 3 # DW_AT_name
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.byte 37 # DW_FORM_strx1
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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 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 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 3 # Abbreviation Code
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.byte 46 # DW_TAG_subprogram
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.byte 0 # DW_CHILDREN_no
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.byte 17 # DW_AT_low_pc
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.byte 27 # DW_FORM_addrx
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.byte 18 # DW_AT_high_pc
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.byte 6 # DW_FORM_data4
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.byte 64 # DW_AT_frame_base
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.byte 24 # DW_FORM_exprloc
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.byte 3 # DW_AT_name
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.byte 37 # DW_FORM_strx1
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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 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 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 37 # DW_FORM_strx1
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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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.Lcu_begin0:
129+
.long 75 # Length of Unit
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.short 5 # DWARF version number
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.byte 1 # DWARF Unit Type
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.byte 8 # Address Size (in bytes)
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.long .debug_abbrev # Offset Into Abbrev. Section
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135+
.byte 1 # Abbrev [1] 0xc:0x43 DW_TAG_compile_unit
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.byte 0 # DW_AT_producer
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.short 4 # DW_AT_language
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.byte 1 # DW_AT_name
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.long .Lstr_offsets_base0 # DW_AT_str_offsets_base
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.long 0 # DW_AT_stmt_list
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.byte 2 # DW_AT_comp_dir
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.long .Laddr_table_base0 # DW_AT_addr_base
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.quad 0 # DW_AT_low_pc
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.byte 0 # DW_AT_ranges
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.long .Lrnglists_table_base0 # DW_AT_rnglists_base
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.byte 2 # Abbrev [2] 0x2b:0x10 DW_TAG_subprogram
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.byte 0 # DW_AT_low_pc
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.long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
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.byte 1 # DW_AT_frame_base
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.byte 86
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.byte 3 # DW_AT_linkage_name
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.byte 4 # DW_AT_name
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.byte 1 # DW_AT_decl_file
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.byte 1 # DW_AT_decl_line
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.long 74 # DW_AT_type
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# DW_AT_external
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.byte 3 # Abbrev [3] 0x3b:0xf DW_TAG_subprogram
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.byte 1 # DW_AT_low_pc
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.long .Lfunc_end1-.Lfunc_begin1 # DW_AT_high_pc
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.byte 1 # DW_AT_frame_base
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.byte 86
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.byte 6 # DW_AT_name
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.byte 1 # DW_AT_decl_file
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.byte 5 # DW_AT_decl_line
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.long 74 # DW_AT_type
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# DW_AT_external
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.byte 4 # Abbrev [4] 0x4a:0x4 DW_TAG_base_type
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.byte 5 # 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 0 # End Of Children Mark
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.section .debug_rnglists,"",@progbits
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.long .Ldebug_rnglist_table_end0-.Ldebug_rnglist_table_start0 # Length
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.Ldebug_rnglist_table_start0:
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.short 5 # Version
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.byte 8 # Address size
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.byte 0 # Segment selector size
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.long 1 # Offset entry count
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.Lrnglists_table_base0:
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.long .Ldebug_ranges0-.Lrnglists_table_base0
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.Ldebug_ranges0:
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.byte 3 # DW_RLE_startx_length
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.byte 0 # start index
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.uleb128 .Lfunc_end0-.Lfunc_begin0 # length
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.byte 3 # DW_RLE_startx_length
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.byte 1 # start index
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.uleb128 .Lfunc_end1-.Lfunc_begin1 # length
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.byte 0 # DW_RLE_end_of_list
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.Ldebug_rnglist_table_end0:
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.section .debug_addr,"",@progbits
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.long 20
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.short 5
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.byte 8
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.byte 0
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.Laddr_table_base0:
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.quad .Lfunc_begin0
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.quad .Lfunc_begin1

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