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Differential D104257

[GCOVProfiling] don't profile Fn's w/ noprofile attribute
ClosedPublic

Authored by nickdesaulniers on Jun 14 2021, 12:34 PM.

Details

Reviewers
MaskRay
phosek
Commits
rGbef299286104: [GCOVProfiling] don't profile Fn's w/ noprofile attribute
Summary

Similar to D104475, the Linux kernel would like to avoid compiler
generated code in certain functions. The no_profile function
attribute can be used in C to generate the the noprofile fn attr in IR.
Respect that from GCOVProfiling.

Link: https://lore.kernel.org/lkml/CAKwvOdmPTi93n2L0_yQkrzLdmpxzrOR7zggSzonyaw2PGshApw@mail.gmail.com/

Diff Detail

Unit TestsFailed

TimeTest
40 msx64 debian > LLVM.Transforms/GCOVProfiling::noprofile.ll
80 msx64 windows > LLVM.Transforms/GCOVProfiling::noprofile.ll

Event Timeline

nickdesaulniers created this revision.Jun 14 2021, 12:34 PM
Herald added a subscriber: hiraditya. · View Herald TranscriptJun 14 2021, 12:34 PM
nickdesaulniers requested review of this revision.Jun 14 2021, 12:34 PM
Herald added a project: Restricted Project. · View Herald TranscriptJun 14 2021, 12:34 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
nickdesaulniers planned changes to this revision.Jun 14 2021, 12:35 PM
nickdesaulniers added a subscriber: samitolvanen.

TODO(Nick): trim down test case further.

nickdesaulniers added a parent revision: D104253: [Clang][Codegen] emit noprofile IR Fn Attr for no_instrument_function Fn Attr.Jun 14 2021, 12:35 PM
Harbormaster completed remote builds in B109172: Diff 351965.Jun 14 2021, 1:46 PM
MaskRay added inline comments.Jun 14 2021, 1:56 PM
llvm/test/Transforms/GCOVProfiling/noprofile.ll
1

You may use module-flags.ll as a template. It is simple enough.

nickdesaulniers edited parent revisions, added: D104475: [Clang][Codegen] Add GNU function attribute 'no_profile' and lower it to noprofile; removed: D104253: [Clang][Codegen] emit noprofile IR Fn Attr for no_instrument_function Fn Attr.Jun 17 2021, 11:17 AM
nickdesaulniers updated this revision to Diff 352877.Jun 17 2021, 4:58 PM
nickdesaulniers retitled this revision from [WIP][GCOVProfiling] don't profile Fn's w/ noprofile attribute to [GCOVProfiling] don't profile Fn's w/ noprofile attribute.
nickdesaulniers edited the summary of this revision. (Show Details)
  • reduce test case, remove WIP
nickdesaulniers marked an inline comment as done.Jun 17 2021, 4:59 PM
nickdesaulniers updated this revision to Diff 352878.Jun 17 2021, 5:00 PM
  • refresh utils/update_test_checks.py assertions
Harbormaster completed remote builds in B109833: Diff 352878.Jun 18 2021, 10:47 AM
nickdesaulniers edited the summary of this revision. (Show Details)Jun 18 2021, 11:20 AM
MaskRay accepted this revision.Jun 18 2021, 12:16 PM
MaskRay added inline comments.
llvm/test/Transforms/GCOVProfiling/noprofile.ll
3

< %s

Add a file-level comment: Test that the noprofile attribute disables profiling.

4

s/#0/noprofile

in-line attributes are usually clearer for testing purpose.

This revision is now accepted and ready to land.Jun 18 2021, 12:16 PM
MaskRay added a comment.Jun 18 2021, 12:17 PM

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

We don't use the tag.

nickdesaulniers edited the summary of this revision. (Show Details)Jun 18 2021, 12:26 PM
nickdesaulniers added a reviewer: phosek.Jun 18 2021, 12:43 PM
nickdesaulniers updated this revision to Diff 353093.Jun 18 2021, 1:58 PM
  • test mods: add comment, remove -o -, in-line noprofile attr
nickdesaulniers marked 2 inline comments as done.Jun 18 2021, 1:58 PM
This revision was landed with ongoing or failed builds.Jun 18 2021, 2:04 PM
Closed by commit rGbef299286104: [GCOVProfiling] don't profile Fn's w/ noprofile attribute (authored by nickdesaulniers). · Explain Why
This revision was automatically updated to reflect the committed changes.
nickdesaulniers added a commit: rGbef299286104: [GCOVProfiling] don't profile Fn's w/ noprofile attribute.
Harbormaster completed remote builds in B109994: Diff 353093.Jun 19 2021, 11:26 AM

Revision Contents

PathSize
llvm/
lib/
Transforms/
Instrumentation/
2 lines
test/
Transforms/
GCOVProfiling/
71 lines

Diff 351965

llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp

Show First 20 Lines • Show All 843 Lines • ▼ Show 20 Lines for (unsigned i = 0, e = CUNode->getNumOperands(); i != e; ++i) {
for (auto &F : M->functions()) { for (auto &F : M->functions()) {
DISubprogram *SP = F.getSubprogram(); DISubprogram *SP = F.getSubprogram();
unsigned EndLine; unsigned EndLine;
if (!SP) continue; if (!SP) continue;
if (!functionHasLines(F, EndLine) || !isFunctionInstrumented(F)) if (!functionHasLines(F, EndLine) || !isFunctionInstrumented(F))
continue; continue;
// TODO: Functions using scope-based EH are currently not supported. // TODO: Functions using scope-based EH are currently not supported.
if (isUsingScopeBasedEH(F)) continue; if (isUsingScopeBasedEH(F)) continue;
if (F.hasFnAttribute(llvm::Attribute::NoProfile))
continue;
// Add the function line number to the lines of the entry block // Add the function line number to the lines of the entry block
// to have a counter for the function definition. // to have a counter for the function definition.
uint32_t Line = SP->getLine(); uint32_t Line = SP->getLine();
auto Filename = getFilename(SP); auto Filename = getFilename(SP);
BranchProbabilityInfo *BPI = GetBPI(F); BranchProbabilityInfo *BPI = GetBPI(F);
BlockFrequencyInfo *BFI = GetBFI(F); BlockFrequencyInfo *BFI = GetBFI(F);
▲ Show 20 Lines • Show All 533 Lines • Show Last 20 Lines

llvm/test/Transforms/GCOVProfiling/noprofile.ll

  • This file was added.
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
MaskRayUnsubmitted
Done
ReplyInline Actions

You may use module-flags.ll as a template. It is simple enough.

MaskRay: You may use `module-flags.ll` as a template. It is simple enough.
; RUN: opt -passes=insert-gcov-profiling -o - -S %s | FileCheck %s
define dso_local i32 @no_instr(i32 %a) #0 !dbg !9 {
MaskRayUnsubmitted
Done
ReplyInline Actions

< %s

Add a file-level comment: Test that the noprofile attribute disables profiling.

MaskRay: `< %s` Add a file-level comment: Test that the noprofile attribute disables profiling.
; CHECK-LABEL: @no_instr(
MaskRayUnsubmitted
Done
ReplyInline Actions

s/#0/noprofile

in-line attributes are usually clearer for testing purpose.

MaskRay: `s/#0/noprofile` in-line attributes are usually clearer for testing purpose.
; CHECK-NEXT: ret i32 42, !dbg [[DBG11:![0-9]+]]
;
ret i32 42, !dbg !27
}
define dso_local i32 @instr(i32 %a) !dbg !28 {
; CHECK-LABEL: @instr(
; CHECK-NEXT: [[GCOV_CTR:%.*]] = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0), align 4, !dbg [[DBG13:![0-9]+]]
; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[GCOV_CTR]], 1, !dbg [[DBG13]]
; CHECK-NEXT: store i64 [[TMP1]], i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0), align 4, !dbg [[DBG13]]
; CHECK-NEXT: ret i32 42, !dbg [[DBG13]]
;
ret i32 42, !dbg !44
}
attributes #0 = { noprofile }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5, !6}
!llvm.gcov = !{!7}
!llvm.ident = !{!8}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "Nick Desaulniers clang version 13.0.0 (git@github.com:llvm/llvm-project.git b7df99b83a257261369053d4424b4d3229f85106)", isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "foo.c", directory: "/android0/llvm-project")
!2 = !{}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{i32 1, !"wchar_size", i32 4}
!5 = !{i32 7, !"uwtable", i32 1}
!6 = !{i32 7, !"frame-pointer", i32 2}
!7 = !{!"/android0/llvm-project/-.gcno", !"/android0/llvm-project/-.gcda", !0}
!8 = !{!"Nick Desaulniers clang version 13.0.0 (git@github.com:llvm/llvm-project.git b7df99b83a257261369053d4424b4d3229f85106)"}
!9 = distinct !DISubprogram(name: "no_instr", scope: !1, file: !1, line: 5, type: !10, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
!10 = !DISubroutineType(types: !2)
!11 = !DILocation(line: 6, column: 7, scope: !9)
!12 = !DILocation(line: 7, column: 12, scope: !9)
!13 = !DILocation(line: 7, column: 8, scope: !9)
!14 = !DILocation(line: 7, column: 19, scope: !9)
!15 = !DILocation(line: 7, column: 23, scope: !9)
!16 = !DILocation(line: 7, column: 21, scope: !9)
!17 = !DILocation(line: 7, column: 3, scope: !9)
!18 = !DILocation(line: 8, column: 14, scope: !9)
!19 = !DILocation(line: 8, column: 12, scope: !9)
!20 = !DILocation(line: 8, column: 9, scope: !9)
!21 = !DILocation(line: 8, column: 5, scope: !9)
!22 = !DILocation(line: 7, column: 27, scope: !9)
!23 = distinct !{!23, !17, !24, !25}
!24 = !DILocation(line: 8, column: 15, scope: !9)
!25 = !{!"llvm.loop.mustprogress"}
!26 = !DILocation(line: 9, column: 10, scope: !9)
!27 = !DILocation(line: 9, column: 3, scope: !9)
!28 = distinct !DISubprogram(name: "instr", scope: !1, file: !1, line: 12, type: !10, scopeLine: 12, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
!29 = !DILocation(line: 13, column: 7, scope: !28)
!30 = !DILocation(line: 14, column: 12, scope: !28)
!31 = !DILocation(line: 14, column: 8, scope: !28)
!32 = !DILocation(line: 14, column: 19, scope: !28)
!33 = !DILocation(line: 14, column: 23, scope: !28)
!34 = !DILocation(line: 14, column: 21, scope: !28)
!35 = !DILocation(line: 14, column: 3, scope: !28)
!36 = !DILocation(line: 15, column: 14, scope: !28)
!37 = !DILocation(line: 15, column: 12, scope: !28)
!38 = !DILocation(line: 15, column: 9, scope: !28)
!39 = !DILocation(line: 15, column: 5, scope: !28)
!40 = !DILocation(line: 14, column: 27, scope: !28)
!41 = distinct !{!41, !35, !42, !25}
!42 = !DILocation(line: 15, column: 15, scope: !28)
!43 = !DILocation(line: 16, column: 10, scope: !28)
!44 = !DILocation(line: 16, column: 3, scope: !28)