Port CodegenLLVM::optimize to new pass manager #3947
Comments
|
I will take this one when #3956 landed. :) |
chenhengqi
added a commit
to chenhengqi/bcc
that referenced
this issue
Apr 28, 2022
There are two pass managers in LLVM. Currently BCC uses the legacy one.
Switch to the new pass manager because the legacy one will be removed
in upcoming releases of LLVM.
Running the following script:
```
from bcc import BPF
bpf_text = '''
static int foobar()
{
bpf_trace_printk("enter vfs_read");
return 0;
}
KFUNC_PROBE(vfs_read)
{
return foobar();
}
'''
BPF(text=bpf_text, debug=1)
```
The IR output is the same with or without this change using LLVM 15:
; ModuleID = 'sscanf'
source_filename = "sscanf"
; ModuleID = '/virtual/main.c'
source_filename = "/virtual/main.c"
target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "bpf-pc-linux"
@_version = dso_local global i32 332032, section "version", align 4, !dbg !0
@_license = dso_local global [4 x i8] c"GPL\00", section "license", align 1, !dbg !5
@__const.foobar._fmt = private unnamed_addr constant [15 x i8] c"enter vfs_read\00", align 1
@llvm.compiler.used = appending global [2 x ptr] [ptr @_license, ptr @_version], section "llvm.metadata"
; Function Attrs: alwaysinline nounwind
define dso_local i32 @kfunc__vfs_read(ptr nocapture noundef readnone %0) local_unnamed_addr #0 section ".bpf.fn.kfunc__vfs_read" !dbg !33 {
%2 = alloca [15 x i8], align 1
call void @llvm.dbg.value(metadata ptr %0, metadata !39, metadata !DIExpression()), !dbg !41
call void @llvm.dbg.value(metadata ptr undef, metadata !42, metadata !DIExpression()) iovisor#4, !dbg !45
call void @llvm.lifetime.start.p0(i64 15, ptr nonnull %2) iovisor#4, !dbg !47
call void @llvm.dbg.declare(metadata ptr %2, metadata !53, metadata !DIExpression()) iovisor#4, !dbg !58
call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(15) %2, ptr noundef nonnull align 1 dereferenceable(15) @__const.foobar._fmt, i64 15, i1 false) iovisor#4, !dbg !58
%3 = call i32 (ptr, i64, ...) inttoptr (i64 6 to ptr)(ptr noundef nonnull %2, i64 noundef 15) iovisor#4, !dbg !59
call void @llvm.lifetime.end.p0(i64 15, ptr nonnull %2) iovisor#4, !dbg !60
call void @llvm.dbg.value(metadata i32 0, metadata !40, metadata !DIExpression()), !dbg !41
ret i32 0, !dbg !61
}
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) iovisor#2
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) iovisor#2
; Function Attrs: alwaysinline argmemonly mustprogress nofree nounwind willreturn
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) iovisor#3
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.value(metadata, metadata, metadata) #1
attributes #0 = { alwaysinline nounwind "frame-pointer"="none" "min-legal-vector-width"="0" "no-jump-tables"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn }
attributes iovisor#2 = { alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn }
attributes iovisor#3 = { alwaysinline argmemonly mustprogress nofree nounwind willreturn }
attributes iovisor#4 = { nounwind }
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!27, !28, !29, !30, !31}
!llvm.ident = !{!32}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "_version", scope: !2, file: !14, line: 526, type: !26, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
!3 = !DIFile(filename: "/virtual/main.c", directory: "/home/ubuntu/sources/bpf-next")
!4 = !{!0, !5, !12}
!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
!6 = distinct !DIGlobalVariable(name: "_license", scope: !2, file: !7, line: 26, type: !8, isLocal: false, isDefinition: true)
!7 = !DIFile(filename: "/virtual/include/bcc/footer.h", directory: "")
!8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 32, elements: !10)
!9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
!10 = !{!11}
!11 = !DISubrange(count: 4)
!12 = !DIGlobalVariableExpression(var: !13, expr: !DIExpression())
!13 = distinct !DIGlobalVariable(name: "bpf_trace_printk_", scope: !2, file: !14, line: 542, type: !15, isLocal: true, isDefinition: true)
!14 = !DIFile(filename: "/virtual/include/bcc/helpers.h", directory: "")
!15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
!16 = !DISubroutineType(types: !17)
!17 = !{!18, !19, !21, null}
!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64)
!20 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
!21 = !DIDerivedType(tag: DW_TAG_typedef, name: "u64", file: !22, line: 23, baseType: !23)
!22 = !DIFile(filename: "include/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!23 = !DIDerivedType(tag: DW_TAG_typedef, name: "__u64", file: !24, line: 31, baseType: !25)
!24 = !DIFile(filename: "include/uapi/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!25 = !DIBasicType(name: "unsigned long long", size: 64, encoding: DW_ATE_unsigned)
!26 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
!27 = !{i32 7, !"Dwarf Version", i32 4}
!28 = !{i32 2, !"Debug Info Version", i32 3}
!29 = !{i32 1, !"wchar_size", i32 4}
!30 = !{i32 7, !"PIC Level", i32 2}
!31 = !{i32 7, !"PIE Level", i32 2}
!32 = !{!"Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435"}
!33 = distinct !DISubprogram(name: "kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 23, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !38)
!34 = !DIFile(filename: "/virtual/main.c", directory: "")
!35 = !DISubroutineType(types: !36)
!36 = !{!18, !37}
!37 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !25, size: 64)
!38 = !{!39, !40}
!39 = !DILocalVariable(name: "ctx", arg: 1, scope: !33, file: !34, line: 23, type: !37)
!40 = !DILocalVariable(name: "__ret", scope: !33, file: !34, line: 23, type: !18)
!41 = !DILocation(line: 0, scope: !33)
!42 = !DILocalVariable(name: "ctx", arg: 1, scope: !43, file: !34, line: 23, type: !37)
!43 = distinct !DISubprogram(name: "____kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 24, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !44)
!44 = !{!42}
!45 = !DILocation(line: 0, scope: !43, inlinedAt: !46)
!46 = distinct !DILocation(line: 23, column: 1, scope: !33)
!47 = !DILocation(line: 15, column: 5, scope: !48, inlinedAt: !57)
!48 = distinct !DILexicalBlock(scope: !49, file: !34, line: 15, column: 3)
!49 = distinct !DISubprogram(name: "foobar", scope: !34, file: !34, line: 13, type: !50, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !52)
!50 = !DISubroutineType(types: !51)
!51 = !{!18}
!52 = !{!53}
!53 = !DILocalVariable(name: "_fmt", scope: !48, file: !34, line: 15, type: !54)
!54 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 120, elements: !55)
!55 = !{!56}
!56 = !DISubrange(count: 15)
!57 = distinct !DILocation(line: 25, column: 9, scope: !43, inlinedAt: !46)
!58 = !DILocation(line: 15, column: 10, scope: !48, inlinedAt: !57)
!59 = !DILocation(line: 15, column: 37, scope: !48, inlinedAt: !57)
!60 = !DILocation(line: 15, column: 76, scope: !49, inlinedAt: !57)
!61 = !DILocation(line: 23, column: 1, scope: !33)
Closes iovisor#3947.
References:
[0]: https://llvm.org/docs/NewPassManager.html
[1]: https://blog.llvm.org/posts/2021-03-26-the-new-pass-manager/
Signed-off-by: Hengqi Chen <[email protected]>
yonghong-song
pushed a commit
that referenced
this issue
May 2, 2022
There are two pass managers in LLVM. Currently BCC uses the legacy one.
Switch to the new pass manager because the legacy one will be removed
in upcoming releases of LLVM.
Running the following script:
```
from bcc import BPF
bpf_text = '''
static int foobar()
{
bpf_trace_printk("enter vfs_read");
return 0;
}
KFUNC_PROBE(vfs_read)
{
return foobar();
}
'''
BPF(text=bpf_text, debug=1)
```
The IR output is the same with or without this change using LLVM 15:
; ModuleID = 'sscanf'
source_filename = "sscanf"
; ModuleID = '/virtual/main.c'
source_filename = "/virtual/main.c"
target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "bpf-pc-linux"
@_version = dso_local global i32 332032, section "version", align 4, !dbg !0
@_license = dso_local global [4 x i8] c"GPL\00", section "license", align 1, !dbg !5
@__const.foobar._fmt = private unnamed_addr constant [15 x i8] c"enter vfs_read\00", align 1
@llvm.compiler.used = appending global [2 x ptr] [ptr @_license, ptr @_version], section "llvm.metadata"
; Function Attrs: alwaysinline nounwind
define dso_local i32 @kfunc__vfs_read(ptr nocapture noundef readnone %0) local_unnamed_addr #0 section ".bpf.fn.kfunc__vfs_read" !dbg !33 {
%2 = alloca [15 x i8], align 1
call void @llvm.dbg.value(metadata ptr %0, metadata !39, metadata !DIExpression()), !dbg !41
call void @llvm.dbg.value(metadata ptr undef, metadata !42, metadata !DIExpression()) #4, !dbg !45
call void @llvm.lifetime.start.p0(i64 15, ptr nonnull %2) #4, !dbg !47
call void @llvm.dbg.declare(metadata ptr %2, metadata !53, metadata !DIExpression()) #4, !dbg !58
call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(15) %2, ptr noundef nonnull align 1 dereferenceable(15) @__const.foobar._fmt, i64 15, i1 false) #4, !dbg !58
%3 = call i32 (ptr, i64, ...) inttoptr (i64 6 to ptr)(ptr noundef nonnull %2, i64 noundef 15) #4, !dbg !59
call void @llvm.lifetime.end.p0(i64 15, ptr nonnull %2) #4, !dbg !60
call void @llvm.dbg.value(metadata i32 0, metadata !40, metadata !DIExpression()), !dbg !41
ret i32 0, !dbg !61
}
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2
; Function Attrs: alwaysinline argmemonly mustprogress nofree nounwind willreturn
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #3
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.value(metadata, metadata, metadata) #1
attributes #0 = { alwaysinline nounwind "frame-pointer"="none" "min-legal-vector-width"="0" "no-jump-tables"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn }
attributes #2 = { alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn }
attributes #3 = { alwaysinline argmemonly mustprogress nofree nounwind willreturn }
attributes #4 = { nounwind }
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!27, !28, !29, !30, !31}
!llvm.ident = !{!32}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "_version", scope: !2, file: !14, line: 526, type: !26, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
!3 = !DIFile(filename: "/virtual/main.c", directory: "/home/ubuntu/sources/bpf-next")
!4 = !{!0, !5, !12}
!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
!6 = distinct !DIGlobalVariable(name: "_license", scope: !2, file: !7, line: 26, type: !8, isLocal: false, isDefinition: true)
!7 = !DIFile(filename: "/virtual/include/bcc/footer.h", directory: "")
!8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 32, elements: !10)
!9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
!10 = !{!11}
!11 = !DISubrange(count: 4)
!12 = !DIGlobalVariableExpression(var: !13, expr: !DIExpression())
!13 = distinct !DIGlobalVariable(name: "bpf_trace_printk_", scope: !2, file: !14, line: 542, type: !15, isLocal: true, isDefinition: true)
!14 = !DIFile(filename: "/virtual/include/bcc/helpers.h", directory: "")
!15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
!16 = !DISubroutineType(types: !17)
!17 = !{!18, !19, !21, null}
!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64)
!20 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
!21 = !DIDerivedType(tag: DW_TAG_typedef, name: "u64", file: !22, line: 23, baseType: !23)
!22 = !DIFile(filename: "include/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!23 = !DIDerivedType(tag: DW_TAG_typedef, name: "__u64", file: !24, line: 31, baseType: !25)
!24 = !DIFile(filename: "include/uapi/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!25 = !DIBasicType(name: "unsigned long long", size: 64, encoding: DW_ATE_unsigned)
!26 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
!27 = !{i32 7, !"Dwarf Version", i32 4}
!28 = !{i32 2, !"Debug Info Version", i32 3}
!29 = !{i32 1, !"wchar_size", i32 4}
!30 = !{i32 7, !"PIC Level", i32 2}
!31 = !{i32 7, !"PIE Level", i32 2}
!32 = !{!"Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435"}
!33 = distinct !DISubprogram(name: "kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 23, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !38)
!34 = !DIFile(filename: "/virtual/main.c", directory: "")
!35 = !DISubroutineType(types: !36)
!36 = !{!18, !37}
!37 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !25, size: 64)
!38 = !{!39, !40}
!39 = !DILocalVariable(name: "ctx", arg: 1, scope: !33, file: !34, line: 23, type: !37)
!40 = !DILocalVariable(name: "__ret", scope: !33, file: !34, line: 23, type: !18)
!41 = !DILocation(line: 0, scope: !33)
!42 = !DILocalVariable(name: "ctx", arg: 1, scope: !43, file: !34, line: 23, type: !37)
!43 = distinct !DISubprogram(name: "____kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 24, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !44)
!44 = !{!42}
!45 = !DILocation(line: 0, scope: !43, inlinedAt: !46)
!46 = distinct !DILocation(line: 23, column: 1, scope: !33)
!47 = !DILocation(line: 15, column: 5, scope: !48, inlinedAt: !57)
!48 = distinct !DILexicalBlock(scope: !49, file: !34, line: 15, column: 3)
!49 = distinct !DISubprogram(name: "foobar", scope: !34, file: !34, line: 13, type: !50, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !52)
!50 = !DISubroutineType(types: !51)
!51 = !{!18}
!52 = !{!53}
!53 = !DILocalVariable(name: "_fmt", scope: !48, file: !34, line: 15, type: !54)
!54 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 120, elements: !55)
!55 = !{!56}
!56 = !DISubrange(count: 15)
!57 = distinct !DILocation(line: 25, column: 9, scope: !43, inlinedAt: !46)
!58 = !DILocation(line: 15, column: 10, scope: !48, inlinedAt: !57)
!59 = !DILocation(line: 15, column: 37, scope: !48, inlinedAt: !57)
!60 = !DILocation(line: 15, column: 76, scope: !49, inlinedAt: !57)
!61 = !DILocation(line: 23, column: 1, scope: !33)
Closes #3947.
References:
[0]: https://llvm.org/docs/NewPassManager.html
[1]: https://blog.llvm.org/posts/2021-03-26-the-new-pass-manager/
Signed-off-by: Hengqi Chen <[email protected]>
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Using LLVM's legacy PM for optimization pipeline was deprecated in 13.0.0 and the relevant functionality was scheduled to be removed after 14.0.0 (got delayed). The legacy PM for code generation (assembly, object file generation; mainly addPassesToEmitFile) is still supported.
Clang dropped legacy PM support in D123609 (milestone: 15.0.0). I plan to remove instrumentation passes like gcov, PGO, and sanitizers (milestone: 15.0.0).
LLVM's legacy PM for optimization pipeline may be completely removed in 16.0.0 (
llvm::create*Pass,populateModulePassManager, etc). llvm-projectclang/lib/CodeGen/BackendUtil.cppcan serve as an example using the new pass manager.The text was updated successfully, but these errors were encountered: