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llvm-project/llvm/test/CodeGen/BPF/BTF/map-def.ll
Yonghong Song 152a9fef1b BPF: permit .maps section variables with typedef type 
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
2020-07-12 09:42:25 -07:00

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; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
; Source code:
; struct key_type {
; int a;
; int b;
; };
; struct map_type {
; struct key_type *key;
; unsigned *value;
; };
; struct map_type __attribute__((section(".maps"))) hash_map;
; Compilation flag:
; clang -target bpf -O2 -g -S -emit-llvm t.c
%struct.map_type = type { %struct.key_type*, i32* }
%struct.key_type = type { i32, i32 }
@hash_map = dso_local local_unnamed_addr global %struct.map_type zeroinitializer, section ".maps", align 8, !dbg !0
; CHECK: .section .BTF,"",@progbits
; CHECK-NEXT: .short 60319 # 0xeb9f
; CHECK-NEXT: .byte 1
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .long 24
; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 168
; CHECK-NEXT: .long 168
; CHECK-NEXT: .long 65
; CHECK-NEXT: .long 0 # BTF_KIND_PTR(id = 1)
; CHECK-NEXT: .long 33554432 # 0x2000000
; CHECK-NEXT: .long 2
; CHECK-NEXT: .long 1 # BTF_KIND_STRUCT(id = 2)
; CHECK-NEXT: .long 67108866 # 0x4000002
; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 10
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 12
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 32 # 0x20
; CHECK-NEXT: .long 14 # BTF_KIND_INT(id = 3)
; CHECK-NEXT: .long 16777216 # 0x1000000
; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 16777248 # 0x1000020
; CHECK-NEXT: .long 0 # BTF_KIND_PTR(id = 4)
; CHECK-NEXT: .long 33554432 # 0x2000000
; CHECK-NEXT: .long 5
; CHECK-NEXT: .long 18 # BTF_KIND_INT(id = 5)
; CHECK-NEXT: .long 16777216 # 0x1000000
; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 32 # 0x20
; CHECK-NEXT: .long 31 # BTF_KIND_STRUCT(id = 6)
; CHECK-NEXT: .long 67108866 # 0x4000002
; CHECK-NEXT: .long 16
; CHECK-NEXT: .long 40
; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 44
; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 64 # 0x40
; CHECK-NEXT: .long 50 # BTF_KIND_VAR(id = 7)
; CHECK-NEXT: .long 234881024 # 0xe000000
; CHECK-NEXT: .long 6
; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 59 # BTF_KIND_DATASEC(id = 8)
; CHECK-NEXT: .long 251658241 # 0xf000001
; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 7
; CHECK-NEXT: .long hash_map
; CHECK-NEXT: .long 16
; CHECK-NEXT: .byte 0 # string offset=0
; CHECK-NEXT: .ascii "key_type" # string offset=1
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .byte 97 # string offset=10
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .byte 98 # string offset=12
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "int" # string offset=14
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "unsigned int" # string offset=18
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "map_type" # string offset=31
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "key" # string offset=40
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "value" # string offset=44
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "hash_map" # string offset=50
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii ".maps" # string offset=59
; CHECK-NEXT: .byte 0
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!18, !19, !20}
!llvm.ident = !{!21}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "hash_map", scope: !2, file: !3, line: 9, type: !6, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 9.0.0 (trunk 364157) (llvm/trunk 364156)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
!3 = !DIFile(filename: "t.c", directory: "/tmp/home/yhs/work/tests/llvm")
!4 = !{}
!5 = !{!0}
!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "map_type", file: !3, line: 5, size: 128, elements: !7)
!7 = !{!8, !15}
!8 = !DIDerivedType(tag: DW_TAG_member, name: "key", scope: !6, file: !3, line: 6, baseType: !9, size: 64)
!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !10, size: 64)
!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "key_type", file: !3, line: 1, size: 64, elements: !11)
!11 = !{!12, !14}
!12 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !10, file: !3, line: 2, baseType: !13, size: 32)
!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!14 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !10, file: !3, line: 3, baseType: !13, size: 32, offset: 32)
!15 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !6, file: !3, line: 7, baseType: !16, size: 64, offset: 64)
!16 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !17, size: 64)
!17 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
!18 = !{i32 2, !"Dwarf Version", i32 4}
!19 = !{i32 2, !"Debug Info Version", i32 3}
!20 = !{i32 1, !"wchar_size", i32 4}
!21 = !{!"clang version 9.0.0 (trunk 364157) (llvm/trunk 364156)"}
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