1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
; 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:
; union sk_buff {
; int i;
; struct {
; int netid;
; union {
; int dev_id;
; int others;
; } dev;
; } u;
; };
; #define _(x) (__builtin_preserve_access_index(x))
; static int (*bpf_probe_read)(void *dst, int size, void *unsafe_ptr)
; = (void *) 4;
;
; int bpf_prog(union sk_buff *ctx) {
; int dev_id;
; bpf_probe_read(&dev_id, sizeof(int), _(&ctx->u.dev.dev_id));
; return dev_id;
; }
; Compilation flag:
; clang -target bpf -O2 -g -S -emit-llvm test.c
%union.sk_buff = type { %struct.anon }
%struct.anon = type { i32, %union.anon }
%union.anon = type { i32 }
; Function Attrs: nounwind
define dso_local i32 @bpf_prog(%union.sk_buff*) local_unnamed_addr #0 !dbg !15 {
%2 = alloca i32, align 4
call void @llvm.dbg.value(metadata %union.sk_buff* %0, metadata !32, metadata !DIExpression()), !dbg !34
%3 = bitcast i32* %2 to i8*, !dbg !35
call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %3) #4, !dbg !35
%4 = tail call %union.sk_buff* @llvm.preserve.union.access.index.p0s_union.sk_buffs.p0s_union.sk_buffs(%union.sk_buff* %0, i32 1), !dbg !36, !llvm.preserve.access.index !19
%5 = getelementptr inbounds %union.sk_buff, %union.sk_buff* %4, i64 0, i32 0, !dbg !36
%6 = tail call %union.anon* @llvm.preserve.struct.access.index.p0s_union.anons.p0s_struct.anons(%struct.anon* %5, i32 1, i32 1), !dbg !36, !llvm.preserve.access.index !23
%7 = tail call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(%union.anon* %6, i32 0), !dbg !36, !llvm.preserve.access.index !27
%8 = bitcast %union.anon* %7 to i8*, !dbg !36
%9 = call i32 inttoptr (i64 4 to i32 (i8*, i32, i8*)*)(i8* nonnull %3, i32 4, i8* %8) #4, !dbg !37
%10 = load i32, i32* %2, align 4, !dbg !38, !tbaa !39
call void @llvm.dbg.value(metadata i32 %10, metadata !33, metadata !DIExpression()), !dbg !34
call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %3) #4, !dbg !43
ret i32 %10, !dbg !44
}
; 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 105
; CHECK-NEXT: .long 0 # BTF_KIND_PTR(id = 1)
; CHECK-NEXT: .long 33554432 # 0x2000000
; CHECK-NEXT: .long 2
; CHECK-NEXT: .long 1 # BTF_KIND_UNION(id = 2)
; CHECK-NEXT: .long 83886082 # 0x5000002
; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 9
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 11
; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 13 # 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_STRUCT(id = 4)
; CHECK-NEXT: .long 67108866 # 0x4000002
; CHECK-NEXT: .long 8
; CHECK-NEXT: .long 17
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 23
; CHECK-NEXT: .long 5
; CHECK-NEXT: .long 32 # 0x20
; CHECK-NEXT: .long 0 # BTF_KIND_UNION(id = 5)
; CHECK-NEXT: .long 83886082 # 0x5000002
; CHECK-NEXT: .long 4
; CHECK-NEXT: .long 27
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 34
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 0 # 0x0
; CHECK-NEXT: .long 0 # BTF_KIND_FUNC_PROTO(id = 6)
; CHECK-NEXT: .long 218103809 # 0xd000001
; CHECK-NEXT: .long 3
; CHECK-NEXT: .long 41
; CHECK-NEXT: .long 1
; CHECK-NEXT: .long 45 # BTF_KIND_FUNC(id = 7)
; CHECK-NEXT: .long 201326592 # 0xc000000
; CHECK-NEXT: .long 6
; CHECK-NEXT: .byte 0 # string offset=0
; CHECK-NEXT: .ascii "sk_buff" # string offset=1
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .byte 105 # string offset=9
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .byte 117 # string offset=11
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "int" # string offset=13
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "netid" # string offset=17
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "dev" # string offset=23
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "dev_id" # string offset=27
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "others" # string offset=34
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "ctx" # string offset=41
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "bpf_prog" # string offset=45
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii ".text" # string offset=54
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "/tmp/home/yhs/work/tests/llvm/test.c" # string offset=60
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .ascii "0:1:1:0" # string offset=97
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .section .BTF.ext,"",@progbits
; CHECK-NEXT: .short 60319 # 0xeb9f
; CHECK-NEXT: .byte 1
; CHECK-NEXT: .byte 0
; CHECK-NEXT: .long 40
; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 20
; CHECK-NEXT: .long 20
; CHECK-NEXT: .long 76
; CHECK-NEXT: .long 96
; CHECK-NEXT: .long 24
; CHECK-NEXT: .long 120
; CHECK-NEXT: .long 0
; CHECK-NEXT: .long 8 # FuncInfo
; CHECK: .long 12 # OffsetReloc
; CHECK-NEXT: .long 54 # Offset reloc section string offset=54
; CHECK-NEXT: .long 1
; CHECK-NEXT: .long .Ltmp2
; CHECK-NEXT: .long 2
; CHECK-NEXT: .long 97
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
; Function Attrs: nounwind readnone
declare %union.sk_buff* @llvm.preserve.union.access.index.p0s_union.sk_buffs.p0s_union.sk_buffs(%union.sk_buff*, i32 immarg) #2
; Function Attrs: nounwind readnone
declare %union.anon* @llvm.preserve.struct.access.index.p0s_union.anons.p0s_struct.anons(%struct.anon*, i32 immarg, i32 immarg) #2
; Function Attrs: nounwind readnone
declare %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(%union.anon*, i32 immarg) #2
; Function Attrs: argmemonly nounwind
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata) #3
attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { argmemonly nounwind }
attributes #2 = { nounwind readnone }
attributes #3 = { nounwind readnone speculatable }
attributes #4 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !12, !13}
!llvm.ident = !{!14}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0 (trunk 360739) (llvm/trunk 360747)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, nameTableKind: None)
!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/llvm")
!2 = !{}
!3 = !{!4}
!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
!5 = distinct !DIGlobalVariable(name: "bpf_probe_read", scope: !0, file: !1, line: 12, type: !6, isLocal: true, isDefinition: true)
!6 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !7, size: 64)
!7 = !DISubroutineType(types: !8)
!8 = !{!9, !10, !9, !10}
!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
!11 = !{i32 2, !"Dwarf Version", i32 4}
!12 = !{i32 2, !"Debug Info Version", i32 3}
!13 = !{i32 1, !"wchar_size", i32 4}
!14 = !{!"clang version 9.0.0 (trunk 360739) (llvm/trunk 360747)"}
!15 = distinct !DISubprogram(name: "bpf_prog", scope: !1, file: !1, line: 15, type: !16, scopeLine: 15, flags: DIFlagPrototyped, isLocal: false, isDefinition: true, isOptimized: true, unit: !0, retainedNodes: !31)
!16 = !DISubroutineType(types: !17)
!17 = !{!9, !18}
!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
!19 = distinct !DICompositeType(tag: DW_TAG_union_type, name: "sk_buff", file: !1, line: 1, size: 64, elements: !20)
!20 = !{!21, !22}
!21 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !19, file: !1, line: 2, baseType: !9, size: 32)
!22 = !DIDerivedType(tag: DW_TAG_member, name: "u", scope: !19, file: !1, line: 9, baseType: !23, size: 64)
!23 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !19, file: !1, line: 3, size: 64, elements: !24)
!24 = !{!25, !26}
!25 = !DIDerivedType(tag: DW_TAG_member, name: "netid", scope: !23, file: !1, line: 4, baseType: !9, size: 32)
!26 = !DIDerivedType(tag: DW_TAG_member, name: "dev", scope: !23, file: !1, line: 8, baseType: !27, size: 32, offset: 32)
!27 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !23, file: !1, line: 5, size: 32, elements: !28)
!28 = !{!29, !30}
!29 = !DIDerivedType(tag: DW_TAG_member, name: "dev_id", scope: !27, file: !1, line: 6, baseType: !9, size: 32)
!30 = !DIDerivedType(tag: DW_TAG_member, name: "others", scope: !27, file: !1, line: 7, baseType: !9, size: 32)
!31 = !{!32, !33}
!32 = !DILocalVariable(name: "ctx", arg: 1, scope: !15, file: !1, line: 15, type: !18)
!33 = !DILocalVariable(name: "dev_id", scope: !15, file: !1, line: 16, type: !9)
!34 = !DILocation(line: 0, scope: !15)
!35 = !DILocation(line: 16, column: 3, scope: !15)
!36 = !DILocation(line: 17, column: 40, scope: !15)
!37 = !DILocation(line: 17, column: 3, scope: !15)
!38 = !DILocation(line: 18, column: 10, scope: !15)
!39 = !{!40, !40, i64 0}
!40 = !{!"int", !41, i64 0}
!41 = !{!"omnipotent char", !42, i64 0}
!42 = !{!"Simple C/C++ TBAA"}
!43 = !DILocation(line: 19, column: 1, scope: !15)
!44 = !DILocation(line: 18, column: 3, scope: !15)
|
