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[lld] Add lto-pgo-warn-mismatch option

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When enable CSPGO for ThinLTO, there are profile cfg mismatch warnings that will cause lld-link errors (with /WX).
To disable it we have to use an internal "/mllvm:-no-pgo-warn-mismatch" option.
In contrast clang uses option ”-Wno-backend-plugin“ to avoid such warnings and gcc has an explicit "-Wno-coverage-mismatch" option.

Add this "lto-pgo-warn-mismatch" option to lld to help turn on/off the profile mismatch warnings explicitly when build with ThinLTO and CSPGO.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D104431
This commit is contained in:
Yolanda Chen 2021-08-11 13:22:36 +08:00 committed by Wang, Pengfei
parent 98e30a9b47
commit 0cfb00a1c9
15 changed files with 162 additions and 1 deletions
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3
lld/COFF/Config.h
View File

@ -223,6 +223,9 @@ struct Configuration {
// Used for /lto-cs-profile-path
llvm::StringRef ltoCSProfileFile;
// Used for /lto-pgo-warn-mismatch:
bool ltoPGOWarnMismatch = true;
// Used for /call-graph-ordering-file:
llvm::MapVector<std::pair<const SectionChunk *, const SectionChunk *>,
uint64_t>

2
lld/COFF/Driver.cpp
View File

@ -1750,6 +1750,8 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
// Handle miscellaneous boolean flags.
config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
OPT_lto_pgo_warn_mismatch_no, true);
config->allowBind = args.hasFlag(OPT_allowbind, OPT_allowbind_no, true);
config->allowIsolation =
args.hasFlag(OPT_allowisolation, OPT_allowisolation_no, true);

1
lld/COFF/LTO.cpp
View File

@ -87,6 +87,7 @@ static lto::Config createConfig() {
c.DebugPassManager = config->ltoDebugPassManager;
c.CSIRProfile = std::string(config->ltoCSProfileFile);
c.RunCSIRInstr = config->ltoCSProfileGenerate;
c.PGOWarnMismatch = config->ltoPGOWarnMismatch;
if (config->saveTemps)
checkError(c.addSaveTemps(std::string(config->outputFile) + ".",

4
lld/COFF/Options.td
View File

@ -244,6 +244,10 @@ def lto_cs_profile_generate: F<"lto-cs-profile-generate">,
HelpText<"Perform context sensitive PGO instrumentation">;
def lto_cs_profile_file : P<"lto-cs-profile-file",
"Context sensitive profile file path">;
defm lto_pgo_warn_mismatch: B<
"lto-pgo-warn-mismatch",
"turn on warnings about profile cfg mismatch (default)>",
"turn off warnings about profile cfg mismatch">;
def dash_dash_version : Flag<["--"], "version">,
HelpText<"Display the version number and exit">;
def threads

1
lld/ELF/Config.h
View File

@ -178,6 +178,7 @@ struct Configuration {
bool ignoreDataAddressEquality;
bool ignoreFunctionAddressEquality;
bool ltoCSProfileGenerate;
bool ltoPGOWarnMismatch;
bool ltoDebugPassManager;
bool ltoEmitAsm;
bool ltoNewPassManager;

2
lld/ELF/Driver.cpp
View File

@ -1069,6 +1069,8 @@ static void readConfigs(opt::InputArgList &args) {
config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
OPT_no_lto_pgo_warn_mismatch, true);
config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
config->ltoNewPassManager =

1
lld/ELF/LTO.cpp
View File

@ -163,6 +163,7 @@ static lto::Config createConfig() {
c.CSIRProfile = std::string(config->ltoCSProfileFile);
c.RunCSIRInstr = config->ltoCSProfileGenerate;
c.PGOWarnMismatch = config->ltoPGOWarnMismatch;
if (config->emitLLVM) {
c.PostInternalizeModuleHook = [](size_t task, const Module &m) {

3
lld/ELF/Options.td
View File

@ -563,6 +563,9 @@ def lto_cs_profile_generate: FF<"lto-cs-profile-generate">,
HelpText<"Perform context sensitive PGO instrumentation">;
def lto_cs_profile_file: JJ<"lto-cs-profile-file=">,
HelpText<"Context sensitive profile file path">;
defm lto_pgo_warn_mismatch: BB<"lto-pgo-warn-mismatch",
"turn on warnings about profile cfg mismatch (default)>",
"turn off warnings about profile cfg mismatch">;
def lto_obj_path_eq: JJ<"lto-obj-path=">;
def lto_sample_profile: JJ<"lto-sample-profile=">,
HelpText<"Sample profile file path">;

11
lld/test/COFF/Inputs/thinlto_cs.proftext Normal file
View File

@ -0,0 +1,11 @@
# CSIR level Instrumentation Flag
:csir
f
# Func Hash:
1535914979662757887
# Num Counters:
2
# Counter Values:
1
0

57
lld/test/COFF/thinlto-pgo-warn.ll Normal file
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@ -0,0 +1,57 @@
; REQUIRES: x86
; Basic ThinLTO tests.
; RUN: opt -module-summary %s -o %t1.obj
; RUN: llvm-profdata merge %S/Inputs/thinlto_cs.proftext -o %t2.profdata
; Ensure lld generates warnings for profile cfg mismatch.
; RUN: lld-link /out:%t3.dll /dll /noentry /export:f /lto-cs-profile-file:%t2.profdata /lto-pgo-warn-mismatch /opt:lldlto=2 %t1.obj 2>&1 | FileCheck --check-prefix CHECK-WARNING %s
; Ensure lld will not generate warnings for profile cfg mismatch.
; RUN: lld-link /out:%t3.dll /dll /noentry /export:f /lto-cs-profile-file:%t2.profdata /lto-pgo-warn-mismatch:no /opt:lldlto=2 %t1.obj 2>&1 | FileCheck --allow-empty %s
; CHECK-WARNING: warning: {{.*}} function control flow change detected (hash mismatch) f Hash = 1895182923573755903
; CHECK-NOT: warning: {{.*}} function control flow change detected (hash mismatch) f Hash = 1895182923573755903
target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"
define i32 @f(i32 returned %a) #0 {
entry:
ret i32 %a
}
attributes #0 = { "target-cpu"="x86-64" }
!llvm.module.flags = !{!0, !1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 1, !"ProfileSummary", !2}
!2 = !{!3, !4, !5, !6, !7, !8, !9, !10, !11, !12}
!3 = !{!"ProfileFormat", !"InstrProf"}
!4 = !{!"TotalCount", i64 2}
!5 = !{!"MaxCount", i64 1}
!6 = !{!"MaxInternalCount", i64 0}
!7 = !{!"MaxFunctionCount", i64 1}
!8 = !{!"NumCounts", i64 3}
!9 = !{!"NumFunctions", i64 2}
!10 = !{!"IsPartialProfile", i64 0}
!11 = !{!"PartialProfileRatio", double 0.000000e+00}
!12 = !{!"DetailedSummary", !13}
!13 = !{!14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28, !29}
!14 = !{i32 10000, i64 0, i32 0}
!15 = !{i32 100000, i64 0, i32 0}
!16 = !{i32 200000, i64 0, i32 0}
!17 = !{i32 300000, i64 0, i32 0}
!18 = !{i32 400000, i64 0, i32 0}
!19 = !{i32 500000, i64 1, i32 2}
!20 = !{i32 600000, i64 1, i32 2}
!21 = !{i32 700000, i64 1, i32 2}
!22 = !{i32 800000, i64 1, i32 2}
!23 = !{i32 900000, i64 1, i32 2}
!24 = !{i32 950000, i64 1, i32 2}
!25 = !{i32 990000, i64 1, i32 2}
!26 = !{i32 999000, i64 1, i32 2}
!27 = !{i32 999900, i64 1, i32 2}
!28 = !{i32 999990, i64 1, i32 2}
!29 = !{i32 999999, i64 1, i32 2}

11
lld/test/ELF/lto/Inputs/thinlto_cs.proftext Normal file
View File

@ -0,0 +1,11 @@
# CSIR level Instrumentation Flag
:csir
f
# Func Hash:
1535914979662757887
# Num Counters:
2
# Counter Values:
1
0

57
lld/test/ELF/lto/thinlto-pgo-warn.ll Normal file
View File

@ -0,0 +1,57 @@
; REQUIRES: x86
;; Basic ThinLTO tests.
; RUN: opt -module-summary %s -o %t1.bc
; RUN: llvm-profdata merge %S/Inputs/thinlto_cs.proftext -o %t2.profdata
;; Ensure lld generates warnings for profile cfg mismatch.
; RUN: ld.lld --lto-cs-profile-file=%t2.profdata --lto-pgo-warn-mismatch --lto-O2 -shared %t1.bc -o /dev/null 2>&1 | FileCheck --check-prefix CHECK-WARNING %s
;; Ensure lld will not generate warnings for profile cfg mismatch.
; RUN: ld.lld --lto-cs-profile-file=%t2.profdata --no-lto-pgo-warn-mismatch --lto-O2 -shared %t1.bc -o /dev/null 2>&1 | FileCheck --allow-empty %s
; CHECK-WARNING: warning: {{.*}} function control flow change detected (hash mismatch) f Hash = 1895182923573755903
; CHECK-NOT: warning: {{.*}} function control flow change detected (hash mismatch) f Hash = 1895182923573755903
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i32 @f(i32 returned %a) #0 {
entry:
ret i32 %a
}
attributes #0 = { "target-cpu"="x86-64" }
!llvm.module.flags = !{!0, !1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 1, !"ProfileSummary", !2}
!2 = !{!3, !4, !5, !6, !7, !8, !9, !10, !11, !12}
!3 = !{!"ProfileFormat", !"InstrProf"}
!4 = !{!"TotalCount", i64 2}
!5 = !{!"MaxCount", i64 1}
!6 = !{!"MaxInternalCount", i64 0}
!7 = !{!"MaxFunctionCount", i64 1}
!8 = !{!"NumCounts", i64 3}
!9 = !{!"NumFunctions", i64 2}
!10 = !{!"IsPartialProfile", i64 0}
!11 = !{!"PartialProfileRatio", double 0.000000e+00}
!12 = !{!"DetailedSummary", !13}
!13 = !{!14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28, !29}
!14 = !{i32 10000, i64 0, i32 0}
!15 = !{i32 100000, i64 0, i32 0}
!16 = !{i32 200000, i64 0, i32 0}
!17 = !{i32 300000, i64 0, i32 0}
!18 = !{i32 400000, i64 0, i32 0}
!19 = !{i32 500000, i64 1, i32 2}
!20 = !{i32 600000, i64 1, i32 2}
!21 = !{i32 700000, i64 1, i32 2}
!22 = !{i32 800000, i64 1, i32 2}
!23 = !{i32 900000, i64 1, i32 2}
!24 = !{i32 950000, i64 1, i32 2}
!25 = !{i32 990000, i64 1, i32 2}
!26 = !{i32 999000, i64 1, i32 2}
!27 = !{i32 999900, i64 1, i32 2}
!28 = !{i32 999990, i64 1, i32 2}
!29 = !{i32 999999, i64 1, i32 2}

3
llvm/include/llvm/LTO/Config.h
View File

@ -70,6 +70,9 @@ struct Config {
/// Run PGO context sensitive IR instrumentation.
bool RunCSIRInstr = false;
/// Turn on/off the warning about a hash mismatch in the PGO profile data.
bool PGOWarnMismatch = true;
/// Asserts whether we can assume whole program visibility during the LTO
/// link.
bool HasWholeProgramVisibility = false;

5
llvm/lib/LTO/LTOBackend.cpp
View File

@ -74,6 +74,10 @@ static cl::opt<bool> ThinLTOAssumeMerged(
cl::desc("Assume the input has already undergone ThinLTO function "
"importing and the other pre-optimization pipeline changes."));
// Command line option to turn off/on warnings for pgo profile mismatch.
// Defined in Transforms/PGOInstrumentation.cpp: -no-pgo-warn-mismatch
extern cl::opt<bool> NoPGOWarnMismatch;
[[noreturn]] static void reportOpenError(StringRef Path, Twine Msg) {
errs() << "failed to open " << Path << ": " << Msg << '\n';
errs().flush();
@ -221,6 +225,7 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
PGOOpt = PGOOptions(Conf.CSIRProfile, "", Conf.ProfileRemapping,
PGOOptions::IRUse, PGOOptions::CSIRUse,
Conf.AddFSDiscriminator);
NoPGOWarnMismatch = !Conf.PGOWarnMismatch;
} else if (Conf.AddFSDiscriminator) {
PGOOpt = PGOOptions("", "", "", PGOOptions::NoAction,
PGOOptions::NoCSAction, true);

2
llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
View File

@ -200,7 +200,7 @@ static cl::opt<bool>
// Command line option to enable/disable the warning about a hash mismatch in
// the profile data.
static cl::opt<bool>
cl::opt<bool>
NoPGOWarnMismatch("no-pgo-warn-mismatch", cl::init(false), cl::Hidden,
cl::desc("Use this option to turn off/on "
"warnings about profile cfg mismatch."));