379949d79f
Fixes missing inner map struct type definitions [^1]. We should visit
the type of nested array of maps like we do for global maps. This patch
adds a boolean to convey the information to visitTypeEntry and
visitDerivedType that the pointee is a map definition and should be
treated as such.
It ressembles and works with commit 0d21c956a5c1 ("[BPF] Handle nested
wrapper structs in BPF map definition traversal (#144097)") which
focused on directly nested wrapper structs.
Before that patch, this ARRAY_OF_MAPS definition would lead to the BTF
information include the 'missing_type' as "FWD 'missing_type'
fwd_kind=struct":
struct missing_type { uint64_t foo; };
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
[...]
__array(
values, struct {
[...]
__type(value, struct missing_type);
});
} map SEC(".maps");
Which lead to errors while trying to load the map:
libbpf: map 'outer_map.inner': can't determine value size for type [N]:
-22.
To solve this issue, users had to use the struct in a dummy variable or
in a dummy function for the BTF to be generated correctly [^2].
[^1]: https://lore.kernel.org/netdev/aH_cGvgC20iD8qs9@gmail.com/T/#u
[^2]:
https://github.com/cilium/ebpf/discussions/1658#discussioncomment-12491339
---------
Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>
Co-authored-by: Eduard Zingerman <eddyz87@gmail.com>
76 lines
3.7 KiB
LLVM
76 lines
3.7 KiB
LLVM
; RUN: llc -mtriple=bpfel -mcpu=v3 -filetype=obj -o %t1 %s
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; RUN: llvm-objcopy --dump-section='.BTF'=%t2 %t1
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; RUN: %python %p/print_btf.py %t2 | FileCheck -check-prefixes=CHECK-BTF-SHORT %s
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; RUN: %python %p/print_btf.py %t2 | FileCheck -check-prefixes=CHECK-BTF %s
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; Source:
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; struct nested_value_type {
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; int a1;
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; };
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; struct map_type {
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; struct {
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; struct nested_value_type *value;
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; } *values[];
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; };
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; Compilation flags:
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; clang -target bpf -g -O2 -S -emit-llvm prog.c
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; ModuleID = 'prog.c'
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source_filename = "prog.c"
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target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
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target triple = "bpf"
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%struct.map_type = type { [0 x ptr] }
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@array_of_maps = dso_local local_unnamed_addr global %struct.map_type zeroinitializer, section ".maps", align 8, !dbg !0
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; We expect no forward declarations.
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;
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; CHECK-BTF-SHORT-NOT: FWD
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; Assert the whole BTF.
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;
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; CHECK-BTF: [1] PTR '(anon)' type_id=2
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; CHECK-BTF-NEXT: [2] STRUCT 'nested_value_type' size=4 vlen=1
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; CHECK-BTF-NEXT: 'a1' type_id=3 bits_offset=0
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; CHECK-BTF-NEXT: [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
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; CHECK-BTF-NEXT: [4] STRUCT '(anon)' size=8 vlen=1
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; CHECK-BTF-NEXT: 'value' type_id=1 bits_offset=0
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; CHECK-BTF-NEXT: [5] PTR '(anon)' type_id=4
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; CHECK-BTF-NEXT: [6] ARRAY '(anon)' type_id=5 index_type_id=7 nr_elems=0
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; CHECK-BTF-NEXT: [7] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none)
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; CHECK-BTF-NEXT: [8] STRUCT 'map_type' size=0 vlen=1
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; CHECK-BTF-NEXT: 'values' type_id=6 bits_offset=0
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; CHECK-BTF-NEXT: [9] VAR 'array_of_maps' type_id=8, linkage=global
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; CHECK-BTF-NEXT: [10] DATASEC '.maps' size=0 vlen=1
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; CHECK-BTF-NEXT: type_id=9 offset=0 size=0
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!20, !21, !22, !23}
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!llvm.ident = !{!24}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "array_of_maps", scope: !2, file: !3, line: 9, type: !5, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C11, file: !3, producer: "clang version 22.0.0git (git@github.com:llvm/llvm-project.git ed93eaa421b714028b85cc887d80c45991d7207f)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
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!3 = !DIFile(filename: "prog.c", directory: "/home/mtardy/llvm-bug-repro", checksumkind: CSK_MD5, checksum: "9381d9e83e9c0b235a14704224815e96")
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!4 = !{!0}
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!5 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "map_type", file: !3, line: 4, elements: !6)
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!6 = !{!7}
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!7 = !DIDerivedType(tag: DW_TAG_member, name: "values", scope: !5, file: !3, line: 7, baseType: !8)
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!8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, elements: !18)
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!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !10, size: 64)
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!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !5, file: !3, line: 5, size: 64, elements: !11)
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!11 = !{!12}
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!12 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !10, file: !3, line: 6, baseType: !13, size: 64)
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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: "nested_value_type", file: !3, line: 1, size: 32, elements: !15)
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!15 = !{!16}
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!16 = !DIDerivedType(tag: DW_TAG_member, name: "a1", scope: !14, file: !3, line: 2, baseType: !17, size: 32)
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!17 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!18 = !{!19}
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!19 = !DISubrange(count: -1)
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!20 = !{i32 7, !"Dwarf Version", i32 5}
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!21 = !{i32 2, !"Debug Info Version", i32 3}
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!22 = !{i32 1, !"wchar_size", i32 4}
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!23 = !{i32 7, !"frame-pointer", i32 2}
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!24 = !{!"clang version 22.0.0git (git@github.com:llvm/llvm-project.git ed93eaa421b714028b85cc887d80c45991d7207f)"}
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