forked from OSchip/llvm-project
[BPF] fix a bug in __builtin_preserve_field_info() with FIELD_BYTE_SIZE
During deriving proper bitfield access FIELD_BYTE_SIZE,
function Member->getStorageOffsetInBits() is used to
get llvm IR type storage offset in bits so that
the byte size can permit aligned loads/stores with previously
derived FIELD_BYTE_OFFSET.
The function should only be used with bitfield members and it will
assert if ASSERT is turned on during cmake build.
Constant *getStorageOffsetInBits() const {
assert(getTag() == dwarf::DW_TAG_member && isBitField());
if (auto *C = cast_or_null<ConstantAsMetadata>(getExtraData()))
return C->getValue();
return nullptr;
}
This patch fixed the issue by using Member->isBitField()
directly and a test case is added to cover this missing case.
This issue is discovered when running Andrii's linux kernel CO-RE
tests.
Differential Revision: https://reviews.llvm.org/D69761
This commit is contained in:
Yonghong Song
parent
983c4dd8ed
commit
c430533771
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@ -525,7 +525,7 @@ void BPFAbstractMemberAccess::GetStorageBitRange(DICompositeType *CTy,
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uint32_t Index = AccessIndex + 1;
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for (; Index < CTy->getElements().size(); ++Index) {
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auto Member = cast<DIDerivedType>(CTy->getElements()[Index]);
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if (!Member->getStorageOffsetInBits()) {
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if (!Member->isBitField()) {
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EndBitOffset = Member->getOffsetInBits();
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break;
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}
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@ -0,0 +1,86 @@
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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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; RUN: llc -march=bpfel -mattr=+alu32 -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
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; RUN: llc -march=bpfeb -mattr=+alu32 -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
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; Source code:
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; typedef struct s1 { int a1; int a2:4; int a3;} __s1;
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; enum { FIELD_BYTE_SIZE = 1, };
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; int test(__s1 *arg) {
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; return __builtin_preserve_field_info(arg->a2, FIELD_BYTE_SIZE);
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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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%struct.s1 = type { i32, i8, i32 }
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; Function Attrs: nounwind readnone
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define dso_local i32 @test(%struct.s1* readnone %arg) local_unnamed_addr #0 !dbg !11 {
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entry:
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call void @llvm.dbg.value(metadata %struct.s1* %arg, metadata !23, metadata !DIExpression()), !dbg !24
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%0 = tail call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.s1s(%struct.s1* %arg, i32 1, i32 1), !dbg !25, !llvm.preserve.access.index !17
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%1 = tail call i32 @llvm.bpf.preserve.field.info.p0i8(i8* %0, i64 1), !dbg !26
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ret i32 %1, !dbg !27
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}
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; CHECK: r0 = 4
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; CHECK: exit
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; CHECK: .long 6 # BTF_KIND_STRUCT(id = 3)
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; CHECK: .ascii "s1" # string offset=6
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; CHECK: .ascii ".text" # string offset=31
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; CHECK: .ascii "0:1" # string offset=37
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; CHECK: .long 16 # FieldReloc
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; CHECK-NEXT: .long 31 # Field reloc section string offset=31
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; CHECK-NEXT: .long 1
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; CHECK-NEXT: .long .Ltmp{{[0-9]+}}
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; CHECK-NEXT: .long 3
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; CHECK-NEXT: .long 37
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; CHECK-NEXT: .long 1
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; Function Attrs: nounwind readnone
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declare i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.s1s(%struct.s1*, i32, i32) #1
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; Function Attrs: nounwind readnone
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declare i32 @llvm.bpf.preserve.field.info.p0i8(i8*, i64) #1
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; Function Attrs: nounwind readnone speculatable
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declare void @llvm.dbg.value(metadata, metadata, metadata) #2
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attributes #0 = { nounwind readnone "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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attributes #1 = { nounwind readnone }
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attributes #2 = { nounwind readnone speculatable }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!7, !8, !9}
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!llvm.ident = !{!10}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git 6c63b5d6a1cb84a75807804337c855a41c976260)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
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!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/core")
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!2 = !{!3}
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!3 = !DICompositeType(tag: DW_TAG_enumeration_type, file: !1, line: 2, baseType: !4, size: 32, elements: !5)
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!4 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
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!5 = !{!6}
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!6 = !DIEnumerator(name: "FIELD_BYTE_SIZE", value: 1, isUnsigned: true)
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!7 = !{i32 2, !"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 6c63b5d6a1cb84a75807804337c855a41c976260)"}
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!11 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 3, type: !12, scopeLine: 3, flags: DIFlagPrototyped, isDefinition: true, isOptimized: true, unit: !0, retainedNodes: !22)
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!12 = !DISubroutineType(types: !13)
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!13 = !{!14, !15}
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!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
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!16 = !DIDerivedType(tag: DW_TAG_typedef, name: "__s1", file: !1, line: 1, baseType: !17)
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!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "s1", file: !1, line: 1, size: 96, elements: !18)
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!18 = !{!19, !20, !21}
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!19 = !DIDerivedType(tag: DW_TAG_member, name: "a1", scope: !17, file: !1, line: 1, baseType: !14, size: 32)
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!20 = !DIDerivedType(tag: DW_TAG_member, name: "a2", scope: !17, file: !1, line: 1, baseType: !14, size: 4, offset: 32, flags: DIFlagBitField, extraData: i64 32)
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!21 = !DIDerivedType(tag: DW_TAG_member, name: "a3", scope: !17, file: !1, line: 1, baseType: !14, size: 32, offset: 64)
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!22 = !{!23}
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!23 = !DILocalVariable(name: "arg", arg: 1, scope: !11, file: !1, line: 3, type: !15)
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!24 = !DILocation(line: 0, scope: !11)
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!25 = !DILocation(line: 4, column: 45, scope: !11)
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!26 = !DILocation(line: 4, column: 10, scope: !11)
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!27 = !DILocation(line: 4, column: 3, scope: !11)
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