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

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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/

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D104257
This commit is contained in:
Nick Desaulniers 2021-06-18 13:58:34 -07:00
parent a2969894c5
commit de2155141d
2 changed files with 35 additions and 0 deletions
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2
lib/Transforms/Instrumentation/GCOVProfiling.cpp
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@ -849,6 +849,8 @@ bool GCOVProfiler::emitProfileNotes(
continue;
// TODO: Functions using scope-based EH are currently not supported.
if (isUsingScopeBasedEH(F)) continue;
if (F.hasFnAttribute(llvm::Attribute::NoProfile))
continue;
// Add the function line number to the lines of the entry block
// to have a counter for the function definition.

33
test/Transforms/GCOVProfiling/noprofile.ll Normal file
View File

@ -0,0 +1,33 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=insert-gcov-profiling -S %s | FileCheck %s
; Test that the noprofile attribute disables profiling.
define dso_local i32 @no_instr(i32 %a) noprofile !dbg !9 {
; CHECK-LABEL: @no_instr(
; CHECK-NEXT: ret i32 42, !dbg [[DBG6:![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 [[DBG8:![0-9]+]]
; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[GCOV_CTR]], 1, !dbg [[DBG8]]
; CHECK-NEXT: store i64 [[TMP1]], i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__llvm_gcov_ctr, i64 0, i64 0), align 4, !dbg [[DBG8]]
; CHECK-NEXT: ret i32 42, !dbg [[DBG8]]
;
ret i32 42, !dbg !44
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "a.c", directory: "")
!2 = !{}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!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)
!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)
!44 = !DILocation(line: 16, column: 3, scope: !28)