[llvm] r372198 - [BPF] Permit all user instructed offset relocatiions
Yonghong Song via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 17 20:49:07 PDT 2019
Author: yhs
Date: Tue Sep 17 20:49:07 2019
New Revision: 372198
URL: http://llvm.org/viewvc/llvm-project?rev=372198&view=rev
Log:
[BPF] Permit all user instructed offset relocatiions
Currently, not all user specified relocations
(with clang intrinsic __builtin_preserve_access_index())
will turn into relocations.
In the current implementation, a __builtin_preserve_access_index()
chain is turned into relocation only if the result of the clang
intrinsic is used in a function call or a nonzero offset computation
of getelementptr. For all other cases, the relocatiion request
is ignored and the __builtin_preserve_access_index() is turned
into regular getelementptr instructions.
The main reason is to mimic bpf_probe_read() requirement.
But there are other use cases where relocatable offset is
generated but not used for bpf_probe_read(). This patch
relaxed previous constraints when to generate relocations.
Now, all user __builtin_preserve_access_index() will have
relocations generated.
Differential Revision: https://reviews.llvm.org/D67688
Added:
llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-load.ll
llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-ret.ll
Modified:
llvm/trunk/lib/Target/BPF/BPFAbstractMemberAccess.cpp
Modified: llvm/trunk/lib/Target/BPF/BPFAbstractMemberAccess.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/BPF/BPFAbstractMemberAccess.cpp?rev=372198&r1=372197&r2=372198&view=diff
==============================================================================
--- llvm/trunk/lib/Target/BPF/BPFAbstractMemberAccess.cpp (original)
+++ llvm/trunk/lib/Target/BPF/BPFAbstractMemberAccess.cpp Tue Sep 17 20:49:07 2019
@@ -375,6 +375,8 @@ void BPFAbstractMemberAccess::traceAICal
traceGEP(GI, Call, Kind, ParentMeta, ParentAI);
else
BaseAICalls[Call] = Kind;
+ } else {
+ BaseAICalls[Call] = Kind;
}
}
}
@@ -406,6 +408,8 @@ void BPFAbstractMemberAccess::traceBitCa
traceGEP(GI, Parent, Kind, ParentMeta, ParentAI);
else
BaseAICalls[Parent] = Kind;
+ } else {
+ BaseAICalls[Parent] = Kind;
}
}
}
@@ -436,6 +440,8 @@ void BPFAbstractMemberAccess::traceGEP(G
traceGEP(GI, Parent, Kind, ParentMeta, ParentAI);
else
BaseAICalls[Parent] = Kind;
+ } else {
+ BaseAICalls[Parent] = Kind;
}
}
}
Added: llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-load.ll?rev=372198&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-load.ll (added)
+++ llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-load.ll Tue Sep 17 20:49:07 2019
@@ -0,0 +1,82 @@
+; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck %s
+;
+; Source Code:
+; #define _(x) (__builtin_preserve_access_index(x))
+; struct s {int a; int b;};
+; int test(struct s *arg) { return *(const int *)_(&arg->b); }
+; Compiler flag to generate IR:
+; clang -target bpf -S -O2 -g -emit-llvm test.c
+
+%struct.s = type { i32, i32 }
+
+; Function Attrs: nounwind readonly
+define dso_local i32 @test(%struct.s* readonly %arg) local_unnamed_addr #0 !dbg !11 {
+entry:
+ call void @llvm.dbg.value(metadata %struct.s* %arg, metadata !20, metadata !DIExpression()), !dbg !21
+ %0 = tail call i32* @llvm.preserve.struct.access.index.p0i32.p0s_struct.ss(%struct.s* %arg, i32 1, i32 1), !dbg !22, !llvm.preserve.access.index !15
+ %1 = load i32, i32* %0, align 4, !dbg !23, !tbaa !24
+ ret i32 %1, !dbg !28
+}
+
+; CHECK-LABEL: test
+; CHECK: r2 = 4
+; CHECK: r1 += r2
+; CHECK: r0 = *(u32 *)(r1 + 0)
+; CHECK: exit
+;
+; CHECK: .long 1 # BTF_KIND_STRUCT(id = 2)
+;
+; CHECK: .byte 115 # string offset=1
+; CHECK: .ascii ".text" # string offset=20
+; CHECK: .ascii "0:1" # string offset=26
+;
+; CHECK: .long 12 # OffsetReloc
+; CHECK-NEXT: .long 20 # Offset reloc section string offset=20
+; CHECK-NEXT: .long 1
+; CHECK-NEXT: .long .Ltmp{{[0-9]+}}
+; CHECK-NEXT: .long 2
+; CHECK-NEXT: .long 26
+
+; Function Attrs: nounwind readnone
+declare i32* @llvm.preserve.struct.access.index.p0i32.p0s_struct.ss(%struct.s*, i32, i32) #1
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+attributes #0 = { 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" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind readnone speculatable willreturn }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git 6e353b4df3aa452ed4741a5e5caea02b1a876d8c)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/core")
+!2 = !{}
+!3 = !{!4}
+!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
+!5 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !6)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"wchar_size", i32 4}
+!10 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git 6e353b4df3aa452ed4741a5e5caea02b1a876d8c)"}
+!11 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 3, type: !12, scopeLine: 3, flags: DIFlagPrototyped, isDefinition: true, isOptimized: true, unit: !0, retainedNodes: !19)
+!12 = !DISubroutineType(types: !13)
+!13 = !{!6, !14}
+!14 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !15, size: 64)
+!15 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "s", file: !1, line: 2, size: 64, elements: !16)
+!16 = !{!17, !18}
+!17 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !15, file: !1, line: 2, baseType: !6, size: 32)
+!18 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !15, file: !1, line: 2, baseType: !6, size: 32, offset: 32)
+!19 = !{!20}
+!20 = !DILocalVariable(name: "arg", arg: 1, scope: !11, file: !1, line: 3, type: !14)
+!21 = !DILocation(line: 0, scope: !11)
+!22 = !DILocation(line: 3, column: 48, scope: !11)
+!23 = !DILocation(line: 3, column: 34, scope: !11)
+!24 = !{!25, !25, i64 0}
+!25 = !{!"int", !26, i64 0}
+!26 = !{!"omnipotent char", !27, i64 0}
+!27 = !{!"Simple C/C++ TBAA"}
+!28 = !DILocation(line: 3, column: 27, scope: !11)
Added: llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-ret.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-ret.ll?rev=372198&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-ret.ll (added)
+++ llvm/trunk/test/CodeGen/BPF/CORE/offset-reloc-end-ret.ll Tue Sep 17 20:49:07 2019
@@ -0,0 +1,76 @@
+; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck %s
+;
+; Source Code:
+; #define _(x) (__builtin_preserve_access_index(x))
+; struct s {int a; int b;};
+; const void *test(struct s *arg) { return _(&arg->b); }
+; Compiler flag to generate IR:
+; clang -target bpf -S -O2 -g -emit-llvm test.c
+
+%struct.s = type { i32, i32 }
+
+; Function Attrs: nounwind readnone
+define dso_local i8* @test(%struct.s* readnone %arg) local_unnamed_addr #0 !dbg !7 {
+entry:
+ call void @llvm.dbg.value(metadata %struct.s* %arg, metadata !19, metadata !DIExpression()), !dbg !20
+ %0 = tail call i32* @llvm.preserve.struct.access.index.p0i32.p0s_struct.ss(%struct.s* %arg, i32 1, i32 1), !dbg !21, !llvm.preserve.access.index !13
+ %1 = bitcast i32* %0 to i8*, !dbg !21
+ ret i8* %1, !dbg !22
+}
+
+; CHECK-LABEL: test
+; CHECK: r0 = r1
+; CHECK: r1 = 4
+; CHECK: r0 += r1
+; CHECK: exit
+;
+; CHECK: .long 1 # BTF_KIND_STRUCT(id = 2)
+;
+; CHECK: .byte 115 # string offset=1
+; CHECK: .ascii ".text" # string offset=20
+; CHECK: .ascii "0:1" # string offset=63
+;
+; CHECK: .long 12 # OffsetReloc
+; CHECK-NEXT: .long 20 # Offset reloc section string offset=20
+; CHECK-NEXT: .long 1
+; CHECK-NEXT: .long .Ltmp{{[0-9]+}}
+; CHECK-NEXT: .long 2
+; CHECK-NEXT: .long 63
+
+; Function Attrs: nounwind readnone
+declare i32* @llvm.preserve.struct.access.index.p0i32.p0s_struct.ss(%struct.s*, i32, i32) #1
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+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" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind readnone speculatable willreturn }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git 6e353b4df3aa452ed4741a5e5caea02b1a876d8c)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/core")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git 6e353b4df3aa452ed4741a5e5caea02b1a876d8c)"}
+!7 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagPrototyped, isDefinition: true, isOptimized: true, unit: !0, retainedNodes: !18)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10, !12}
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !11, size: 64)
+!11 = !DIDerivedType(tag: DW_TAG_const_type, baseType: null)
+!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64)
+!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "s", file: !1, line: 2, size: 64, elements: !14)
+!14 = !{!15, !17}
+!15 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !13, file: !1, line: 2, baseType: !16, size: 32)
+!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!17 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !13, file: !1, line: 2, baseType: !16, size: 32, offset: 32)
+!18 = !{!19}
+!19 = !DILocalVariable(name: "arg", arg: 1, scope: !7, file: !1, line: 3, type: !12)
+!20 = !DILocation(line: 0, scope: !7)
+!21 = !DILocation(line: 3, column: 42, scope: !7)
+!22 = !DILocation(line: 3, column: 35, scope: !7)
More information about the llvm-commits
mailing list