forked from OSchip/llvm-project
[BPF] Support weak global variables for BTF
Generate types for global variables with "weak" attribute. Keep allocation scope the same for both weak and non-weak globals as ELF symbol table can determine whether a global symbol is weak or not. Differential Revision: https://reviews.llvm.org/D71162
This commit is contained in:
Yonghong Song
parent
d714aa0dfd
commit
5ea611daf9
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@ -1092,7 +1092,7 @@ void BTFDebug::processGlobals(bool ProcessingMapDef) {
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// Only support the following globals:
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// . static variables
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// . non-static global variables
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// . non-static weak or non-weak global variables
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// Essentially means:
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// . .bcc/.data/.rodata DataSec entities only contain static data
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// . Other DataSec entities contain static or initialized global data.
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@ -1101,12 +1101,13 @@ void BTFDebug::processGlobals(bool ProcessingMapDef) {
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// corresponding ELF section flags.
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auto Linkage = Global.getLinkage();
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if (Linkage != GlobalValue::InternalLinkage &&
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Linkage != GlobalValue::ExternalLinkage)
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Linkage != GlobalValue::ExternalLinkage &&
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Linkage != GlobalValue::WeakAnyLinkage)
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continue;
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uint32_t GVarInfo = Linkage == GlobalValue::ExternalLinkage
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? BTF::VAR_GLOBAL_ALLOCATED
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: BTF::VAR_STATIC;
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uint32_t GVarInfo = Linkage == GlobalValue::InternalLinkage
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? BTF::VAR_STATIC
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: BTF::VAR_GLOBAL_ALLOCATED;
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auto VarEntry =
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std::make_unique<BTFKindVar>(Global.getName(), GVTypeId, GVarInfo);
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uint32_t VarId = addType(std::move(VarEntry));
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@ -0,0 +1,66 @@
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; 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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; char g __attribute__((weak)) = 2;
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; int test() {
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; return g;
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; }
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; Compilation flag:
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; clang -target bpf -O2 -g -S -emit-llvm test.c
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@g = weak dso_local local_unnamed_addr global i8 2, align 1, !dbg !0
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; Function Attrs: norecurse nounwind readonly
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define dso_local i32 @test() local_unnamed_addr #0 !dbg !11 {
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entry:
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%0 = load i8, i8* @g, align 1, !dbg !15, !tbaa !16
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%conv = sext i8 %0 to i32, !dbg !15
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ret i32 %conv, !dbg !19
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}
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; CHECK: .long 55 # BTF_KIND_INT(id = 4)
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; CHECK-NEXT: .long 16777216 # 0x1000000
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; CHECK-NEXT: .long 1
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; CHECK-NEXT: .long 16777224 # 0x1000008
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; CHECK-NEXT: .long 60 # BTF_KIND_VAR(id = 5)
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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 62 # BTF_KIND_DATASEC(id = 6)
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; CHECK-NEXT: .long 251658241 # 0xf000001
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; CHECK-NEXT: .long 0
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; CHECK-NEXT: .long 5
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; CHECK-NEXT: .long g
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; CHECK-NEXT: .long 1
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; CHECK: .ascii "char" # string offset=55
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; CHECK: .byte 103 # string offset=60
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; CHECK: .ascii ".data" # string offset=62
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attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "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" }
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!7, !8, !9}
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!llvm.ident = !{!10}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
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!3 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/global")
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!4 = !{}
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!5 = !{!0}
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!6 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
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!7 = !{i32 7, !"Dwarf Version", i32 4}
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!8 = !{i32 2, !"Debug Info Version", i32 3}
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!9 = !{i32 1, !"wchar_size", i32 4}
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!10 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)"}
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!11 = distinct !DISubprogram(name: "test", scope: !3, file: !3, line: 2, type: !12, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4)
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!12 = !DISubroutineType(types: !13)
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!13 = !{!14}
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!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!15 = !DILocation(line: 3, column: 10, scope: !11)
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!16 = !{!17, !17, i64 0}
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!17 = !{!"omnipotent char", !18, i64 0}
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!18 = !{!"Simple C/C++ TBAA"}
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!19 = !DILocation(line: 3, column: 3, scope: !11)
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@ -0,0 +1,65 @@
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; 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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; char g __attribute__((weak));
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; int test() {
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; return g;
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; }
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; Compilation flag:
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; clang -target bpf -O2 -g -S -emit-llvm test.c
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@g = weak dso_local local_unnamed_addr global i8 0, align 1, !dbg !0
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; Function Attrs: norecurse nounwind readonly
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define dso_local i32 @test() local_unnamed_addr #0 !dbg !11 {
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entry:
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%0 = load i8, i8* @g, align 1, !dbg !15, !tbaa !16
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%conv = sext i8 %0 to i32, !dbg !15
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ret i32 %conv, !dbg !19
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}
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; CHECK: .long 55 # BTF_KIND_INT(id = 4)
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; CHECK-NEXT: .long 16777216 # 0x1000000
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; CHECK-NEXT: .long 1
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; CHECK-NEXT: .long 16777224 # 0x1000008
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; CHECK-NEXT: .long 60 # BTF_KIND_VAR(id = 5)
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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 62 # BTF_KIND_DATASEC(id = 6)
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; CHECK-NEXT: .long 251658241 # 0xf000001
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; CHECK-NEXT: .long 0
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; CHECK-NEXT: .long 5
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; CHECK-NEXT: .long g
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; CHECK-NEXT: .long 1
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; CHECK: .ascii "char" # string offset=55
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; CHECK: .byte 103 # string offset=60
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; CHECK: .ascii ".bss" # string offset=62
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attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "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" }
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!7, !8, !9}
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!llvm.ident = !{!10}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
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!3 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/global")
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!4 = !{}
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!5 = !{!0}
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!6 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
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!7 = !{i32 7, !"Dwarf Version", i32 4}
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!8 = !{i32 2, !"Debug Info Version", i32 3}
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!9 = !{i32 1, !"wchar_size", i32 4}
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!10 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)"}
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!11 = distinct !DISubprogram(name: "test", scope: !3, file: !3, line: 2, type: !12, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4)
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!12 = !DISubroutineType(types: !13)
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!13 = !{!14}
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!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!15 = !DILocation(line: 3, column: 10, scope: !11)
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!16 = !{!17, !17, i64 0}
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!17 = !{!"omnipotent char", !18, i64 0}
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!18 = !{!"Simple C/C++ TBAA"}
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!19 = !DILocation(line: 3, column: 3, scope: !11)
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