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llvm-mirror/test/Transforms/SampleProfile/entry_counts.ll
Wei Mi 93d80a543f [SampleFDO] Add use-sample-profile function attribute.
When sampleFDO is enabled, people may expect they can use
-fno-profile-sample-use to opt-out using sample profile for a certain file.
That could be either for debugging purpose or for performance tuning purpose.
However, when thinlto is enabled, if a function in file A compiled with
-fno-profile-sample-use is imported to another file B compiled with
-fprofile-sample-use, the inlined copy of the function in file B may still
get its profile annotated.

The inconsistency may even introduce profile unused warning because if the
target is not compiled with explicit debug information flag, the function
in file A won't have its debug information enabled (debug information will
be enabled implicitly only when -fprofile-sample-use is used). After it is
imported into file B which is compiled with -fprofile-sample-use, profile
annotation for the outline copy of the function will fail because the
function has no debug information, and that will trigger  profile unused
warning.

We add a new attribute use-sample-profile to control whether a function
will use its sample profile no matter for its outline or inline copies.
That will make the behavior of -fno-profile-sample-use consistent.

Differential Revision: https://reviews.llvm.org/D79959
2020-06-02 17:23:17 -07:00

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1.4 KiB
LLVM

; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/entry_counts.prof -S | FileCheck %s
; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/entry_counts.prof -S | FileCheck %s
; According to the profile, function empty() was called 13,293 times.
; CHECK: {{.*}} = !{!"function_entry_count", i64 13294}
define void @empty() #0 !dbg !4 {
entry:
ret void, !dbg !9
}
; This function does not have profile, check if function_entry_count is -1
; CHECK: {{.*}} = !{!"function_entry_count", i64 -1}
define void @no_profile() #0 {
entry:
ret void
}
attributes #0 = {"use-sample-profile"}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!6, !7}
!llvm.ident = !{!8}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.7.0 (trunk 237249) (llvm/trunk 237261)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "entry_counts.c", directory: ".")
!2 = !{}
!4 = distinct !DISubprogram(name: "empty", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0, retainedNodes: !2)
!5 = !DISubroutineType(types: !2)
!6 = !{i32 2, !"Dwarf Version", i32 4}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{!"clang version 3.7.0 (trunk 237249) (llvm/trunk 237261)"}
!9 = !DILocation(line: 1, column: 15, scope: !4)