d15f96fe4b
Extend llvm-objdump to show CO-RE relocations when `-r` option is
passed and object file has .BTF and .BTF.ext sections.
For example, the following C program:
#define __pai __attribute__((preserve_access_index))
struct foo { int i; int j;} __pai;
struct bar { struct foo f[7]; } __pai;
extern void sink(void *);
void root(struct bar *bar) {
sink(&bar[2].f[3].j);
}
Should lead to the following objdump output:
$ clang --target=bpf -O2 -g t.c -c -o - | \
llvm-objdump --no-addresses --no-show-raw-insn -dr -
...
r2 = 0x94
CO-RE <byte_off> [2] struct bar::[2].f[3].j (2:0:3:1)
r1 += r2
call -0x1
R_BPF_64_32 sink
exit
...
More examples could be found in unit tests, see BTFParserTest.cpp.
To achieve this:
- Move CO-RE relocation kinds definitions from BPFCORE.h to BTF.h.
- Extend BTF.h with types derived from BTF::CommonType, e.g.
BTF::IntType and BTF::StrutType, to allow dyn_cast() and access to
type additional data.
- Extend BTFParser to load BTF type and relocation data.
- Modify llvm-objdump.cpp to create instance of BTFParser when
disassembly of object file with BTF sections is processed and `-r`
flag is supplied.
Additional information about CO-RE is available at [1].
[1] https://docs.kernel.org/bpf/llvm_reloc.html
Depends on D149058
Differential Revision: https://reviews.llvm.org/D150079
155 lines
7.3 KiB
LLVM
155 lines
7.3 KiB
LLVM
; REQUIRES: bpf-registered-target
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;; Verify that llvm-objdump can use .BTF.ext to show CO-RE relocation data.
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; RUN: llc --mtriple bpfel %s --filetype=obj -o - | \
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; RUN: llvm-objdump --no-addresses --no-show-raw-insn -dr - | \
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; RUN: FileCheck %s
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; RUN: llc --mtriple bpfeb %s --filetype=obj -o - | \
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; RUN: llvm-objdump --no-addresses --no-show-raw-insn -dr - | \
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; RUN: FileCheck %s
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;; Input generated from the following C code:
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;;
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;; #define __pai __attribute__((preserve_access_index))
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;;
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;; struct buz {
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;; int a;
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;; int b;
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;; } __pai;
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;;
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;; struct foo {
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;; int :4;
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;; int i;
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;; struct buz k[10];
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;; } __pai;
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;;
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;; struct bar {
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;; struct foo f;
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;; } __pai;
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;;
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;; void * volatile g;
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;;
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;; void root(void) {
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;; struct bar *bar = (void *)0;
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;; g = &bar->f;
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;; g = &bar->f.i;
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;; g = &bar->f.k;
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;; g = &bar->f.k[7].a;
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;; g = &bar->f.k[7].b;
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;; g = &bar[1].f.k[7].b;
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;; }
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;;
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;; Using the following command:
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;;
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;; clang --target=bpf -g -O2 -emit-llvm -S t.c
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; CHECK: CO-RE <byte_off> [[[#bar:]]] struct bar::f (0:0)
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; CHECK: CO-RE <byte_off> [[[#bar]]] struct bar::f.i (0:0:0)
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; CHECK: CO-RE <byte_off> [[[#bar]]] struct bar::f.k (0:0:1)
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; CHECK: CO-RE <byte_off> [[[#bar]]] struct bar::f.k[7].a (0:0:1:7:0)
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; CHECK: CO-RE <byte_off> [[[#bar]]] struct bar::f.k[7].b (0:0:1:7:1)
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; CHECK: CO-RE <byte_off> [[[#bar]]] struct bar::[1].f.k[7].b (1:0:1:7:1)
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@g = dso_local global ptr null, align 8, !dbg !0
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@"llvm.bar:0:0$0:0" = external global i64, !llvm.preserve.access.index !14 #0
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@"llvm.bar:0:8$0:0:1" = external global i64, !llvm.preserve.access.index !14 #0
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@"llvm.bar:0:4$0:0:0" = external global i64, !llvm.preserve.access.index !14 #0
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@"llvm.bar:0:64$0:0:1:7:0" = external global i64, !llvm.preserve.access.index !14 #0
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@"llvm.bar:0:68$0:0:1:7:1" = external global i64, !llvm.preserve.access.index !14 #0
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@"llvm.bar:0:156$1:0:1:7:1" = external global i64, !llvm.preserve.access.index !14 #0
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; Function Attrs: nofree nounwind memory(readwrite, argmem: none)
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define dso_local void @root() local_unnamed_addr #1 !dbg !29 {
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entry:
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call void @llvm.dbg.value(metadata ptr null, metadata !33, metadata !DIExpression()), !dbg !34
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%0 = load i64, ptr @"llvm.bar:0:0$0:0", align 8
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%1 = getelementptr i8, ptr null, i64 %0
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%2 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 0, ptr %1)
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store volatile ptr %2, ptr @g, align 8, !dbg !35, !tbaa !36
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%3 = load i64, ptr @"llvm.bar:0:4$0:0:0", align 8
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%4 = getelementptr i8, ptr null, i64 %3
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%5 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 2, ptr %4)
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store volatile ptr %5, ptr @g, align 8, !dbg !40, !tbaa !36
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%6 = load i64, ptr @"llvm.bar:0:8$0:0:1", align 8
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%7 = getelementptr i8, ptr null, i64 %6
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%8 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 1, ptr %7)
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store volatile ptr %8, ptr @g, align 8, !dbg !41, !tbaa !36
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%9 = load i64, ptr @"llvm.bar:0:64$0:0:1:7:0", align 8
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%10 = getelementptr i8, ptr null, i64 %9
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%11 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 3, ptr %10)
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store volatile ptr %11, ptr @g, align 8, !dbg !42, !tbaa !36
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%12 = load i64, ptr @"llvm.bar:0:68$0:0:1:7:1", align 8
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%13 = getelementptr i8, ptr null, i64 %12
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%14 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 4, ptr %13)
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store volatile ptr %14, ptr @g, align 8, !dbg !43, !tbaa !36
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%15 = load i64, ptr @"llvm.bar:0:156$1:0:1:7:1", align 8
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%16 = getelementptr i8, ptr null, i64 %15
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%17 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 5, ptr %16)
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store volatile ptr %17, ptr @g, align 8, !dbg !44, !tbaa !36
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ret void, !dbg !45
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}
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; Function Attrs: nofree nosync nounwind memory(none)
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declare ptr @llvm.bpf.passthrough.p0.p0(i32, ptr) #2
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; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
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declare void @llvm.dbg.value(metadata, metadata, metadata) #3
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attributes #0 = { "btf_ama" }
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attributes #1 = { nofree nounwind memory(readwrite, argmem: none) "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
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attributes #2 = { nofree nosync nounwind memory(none) }
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attributes #3 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!24, !25, !26, !27}
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!llvm.ident = !{!28}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 18, type: !22, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C11, file: !3, producer: "clang version 17.0.0 (/home/eddy/work/llvm-project/clang 2f8c5c0afd1d79a771dd74c8fb1e5bbae6d04eb7)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, retainedTypes: !4, globals: !21, splitDebugInlining: false, nameTableKind: None)
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!3 = !DIFile(filename: "t.c", directory: "/home/eddy/work/tmp", checksumkind: CSK_MD5, checksum: "f7c638151153f385e69bef98e88c80ef")
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!4 = !{!5, !13}
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!5 = !DICompositeType(tag: DW_TAG_array_type, baseType: !6, size: 640, elements: !11)
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!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "buz", file: !3, line: 3, size: 64, elements: !7)
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!7 = !{!8, !10}
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!8 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !6, file: !3, line: 4, baseType: !9, size: 32)
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!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!10 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !6, file: !3, line: 5, baseType: !9, size: 32, offset: 32)
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!11 = !{!12}
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!12 = !DISubrange(count: 10)
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!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !14, size: 64)
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!14 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "bar", file: !3, line: 14, size: 704, elements: !15)
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!15 = !{!16}
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!16 = !DIDerivedType(tag: DW_TAG_member, name: "f", scope: !14, file: !3, line: 15, baseType: !17, size: 704)
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!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo", file: !3, line: 8, size: 704, elements: !18)
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!18 = !{!19, !20}
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!19 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !17, file: !3, line: 10, baseType: !9, size: 32, offset: 32)
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!20 = !DIDerivedType(tag: DW_TAG_member, name: "k", scope: !17, file: !3, line: 11, baseType: !5, size: 640, offset: 64)
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!21 = !{!0}
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!22 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !23)
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!23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
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!24 = !{i32 7, !"Dwarf Version", i32 5}
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!25 = !{i32 2, !"Debug Info Version", i32 3}
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!26 = !{i32 1, !"wchar_size", i32 4}
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!27 = !{i32 7, !"frame-pointer", i32 2}
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!28 = !{!"clang version 17.0.0 (/home/eddy/work/llvm-project/clang 2f8c5c0afd1d79a771dd74c8fb1e5bbae6d04eb7)"}
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!29 = distinct !DISubprogram(name: "root", scope: !3, file: !3, line: 20, type: !30, scopeLine: 20, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !32)
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!30 = !DISubroutineType(types: !31)
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!31 = !{null}
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!32 = !{!33}
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!33 = !DILocalVariable(name: "bar", scope: !29, file: !3, line: 21, type: !13)
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!34 = !DILocation(line: 0, scope: !29)
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!35 = !DILocation(line: 22, column: 5, scope: !29)
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!36 = !{!37, !37, i64 0}
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!37 = !{!"any pointer", !38, i64 0}
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!38 = !{!"omnipotent char", !39, i64 0}
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!39 = !{!"Simple C/C++ TBAA"}
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!40 = !DILocation(line: 23, column: 5, scope: !29)
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!41 = !DILocation(line: 24, column: 5, scope: !29)
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!42 = !DILocation(line: 25, column: 5, scope: !29)
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!43 = !DILocation(line: 26, column: 5, scope: !29)
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!44 = !DILocation(line: 27, column: 5, scope: !29)
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!45 = !DILocation(line: 28, column: 1, scope: !29)
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