Currently, llvm when see a global variable in .maps section,
it ensures its type must be a struct type. Then pointee
will be further evaluated for the structure members.
In normal cases, the pointee type will be skipped.
Although this is what current all bpf programs are doing,
but it is a little bit restrictive. For example, it is legitimate
for users to have:
typedef struct { int key_size; int value_size; } __map_t;
__map_t map __attribute__((section(".maps")));
This patch lifts this restriction and typedef of
a struct type is also allowed for .maps section variables.
To avoid create unnecessary fixup entries when traversal
started with typedef/struct type, the new implementation
first traverse all map struct members and then traverse
the typedef/struct type. This way, in internal BTFDebug
implementation, no fixup entries are generated.
Two new unit tests are added for typedef and const
struct in .maps section. Also tested with kernel bpf selftests.
Differential Revision: https://reviews.llvm.org/D83638
91 lines
5.0 KiB
LLVM
91 lines
5.0 KiB
LLVM
; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
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; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
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;
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; Source code:
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; struct key_type {
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; int a1;
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; };
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; typedef struct map_type {
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; struct key_type *key;
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; } _map_type;
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; typedef _map_type __map_type;
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; __map_type __attribute__((section(".maps"))) hash_map;
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; Compilation flag:
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; clang -target bpf -O2 -g -S -emit-llvm t2.c
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%struct.map_type = type { %struct.key_type* }
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%struct.key_type = type { i32 }
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@hash_map = dso_local local_unnamed_addr global %struct.map_type zeroinitializer, section ".maps", align 8, !dbg !0
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; CHECK: .long 0 # BTF_KIND_PTR(id = 1)
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; CHECK-NEXT: .long 33554432 # 0x2000000
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; CHECK-NEXT: .long 2
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; CHECK-NEXT: .long 1 # BTF_KIND_STRUCT(id = 2)
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; CHECK-NEXT: .long 67108865 # 0x4000001
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; CHECK-NEXT: .long 4
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; CHECK-NEXT: .long 10
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; CHECK-NEXT: .long 3
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; CHECK-NEXT: .long 0 # 0x0
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; CHECK-NEXT: .long 13 # BTF_KIND_INT(id = 3)
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; CHECK-NEXT: .long 16777216 # 0x1000000
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; CHECK-NEXT: .long 4
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; CHECK-NEXT: .long 16777248 # 0x1000020
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; CHECK-NEXT: .long 17 # BTF_KIND_TYPEDEF(id = 4)
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; CHECK-NEXT: .long 134217728 # 0x8000000
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; CHECK-NEXT: .long 5
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; CHECK-NEXT: .long 28 # BTF_KIND_TYPEDEF(id = 5)
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; CHECK-NEXT: .long 134217728 # 0x8000000
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; CHECK-NEXT: .long 6
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; CHECK-NEXT: .long 38 # BTF_KIND_STRUCT(id = 6)
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; CHECK-NEXT: .long 67108865 # 0x4000001
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; CHECK-NEXT: .long 8
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; CHECK-NEXT: .long 47
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; CHECK-NEXT: .long 1
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; CHECK-NEXT: .long 0 # 0x0
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; CHECK-NEXT: .long 51 # BTF_KIND_VAR(id = 7)
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; CHECK-NEXT: .long 234881024 # 0xe000000
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; CHECK-NEXT: .long 4
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; CHECK-NEXT: .long 1
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; CHECK-NEXT: .long 60 # BTF_KIND_DATASEC(id = 8)
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; CHECK-NEXT: .long 251658241 # 0xf000001
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; CHECK-NEXT: .long 0
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; CHECK-NEXT: .long 7
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; CHECK-NEXT: .long hash_map
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; CHECK-NEXT: .long 8
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; CHECK: .ascii "key_type" # string offset=1
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; CHECK: .ascii "a1" # string offset=10
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; CHECK: .ascii "int" # string offset=13
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; CHECK: .ascii "__map_type" # string offset=17
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; CHECK: .ascii "_map_type" # string offset=28
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; CHECK: .ascii "map_type" # string offset=38
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; CHECK: .ascii "key" # string offset=47
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; CHECK: .ascii "hash_map" # string offset=51
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; CHECK: .ascii ".maps" # string offset=60
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!16, !17, !18}
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!llvm.ident = !{!19}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "hash_map", scope: !2, file: !3, line: 8, type: !6, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 11.0.0 (https://github.com/llvm/llvm-project.git b8409c03ed90807f3d49c7d98dceea98cf461f7a)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, splitDebugInlining: false, nameTableKind: None)
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!3 = !DIFile(filename: "t2.c", directory: "/tmp/home/yhs/tmp1")
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!4 = !{}
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!5 = !{!0}
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!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "__map_type", file: !3, line: 7, baseType: !7)
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!7 = !DIDerivedType(tag: DW_TAG_typedef, name: "_map_type", file: !3, line: 6, baseType: !8)
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!8 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "map_type", file: !3, line: 4, size: 64, elements: !9)
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!9 = !{!10}
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!10 = !DIDerivedType(tag: DW_TAG_member, name: "key", scope: !8, file: !3, line: 5, baseType: !11, size: 64)
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!11 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !12, size: 64)
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!12 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "key_type", file: !3, line: 1, size: 32, elements: !13)
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!13 = !{!14}
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!14 = !DIDerivedType(tag: DW_TAG_member, name: "a1", scope: !12, file: !3, line: 2, baseType: !15, size: 32)
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!15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!16 = !{i32 7, !"Dwarf Version", i32 4}
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!17 = !{i32 2, !"Debug Info Version", i32 3}
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!18 = !{i32 1, !"wchar_size", i32 4}
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!19 = !{!"clang version 11.0.0 (https://github.com/llvm/llvm-project.git b8409c03ed90807f3d49c7d98dceea98cf461f7a)"}
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