[llvm-branch-commits] [llvm] [nfc][ThinLTO] Generate import status in per-module combined summary (PR #88024)
Mingming Liu via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Thu May 2 16:16:36 PDT 2024
https://github.com/minglotus-6 updated https://github.com/llvm/llvm-project/pull/88024
>From cfb63d775d43a28b560d938346f1dd4b2dddc765 Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Thu, 4 Apr 2024 11:54:17 -0700
Subject: [PATCH 1/5] function import changes
---
llvm/include/llvm/IR/ModuleSummaryIndex.h | 24 ++++
.../llvm/Transforms/IPO/FunctionImport.h | 18 ++-
llvm/lib/LTO/LTO.cpp | 13 +-
llvm/lib/LTO/LTOBackend.cpp | 5 +-
llvm/lib/LTO/ThinLTOCodeGenerator.cpp | 9 +-
llvm/lib/Transforms/IPO/FunctionImport.cpp | 130 ++++++++++++------
llvm/tools/llvm-link/llvm-link.cpp | 2 +-
7 files changed, 146 insertions(+), 55 deletions(-)
diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
index 286b51bda0e2c1..259fe56ce5f63e 100644
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -296,6 +296,30 @@ template <> struct DenseMapInfo<ValueInfo> {
static unsigned getHashValue(ValueInfo I) { return (uintptr_t)I.getRef(); }
};
+struct SummaryImportInfo {
+ enum class ImportType : uint8_t {
+ NotImported = 0,
+ Declaration = 1,
+ Definition = 2,
+ };
+ unsigned Type : 3;
+ SummaryImportInfo() : Type(static_cast<unsigned>(ImportType::NotImported)) {}
+ SummaryImportInfo(ImportType Type) : Type(static_cast<unsigned>(Type)) {}
+
+ // FIXME: delete the first two set* helper function.
+ void updateType(ImportType InputType) {
+ Type = std::max(Type, static_cast<unsigned>(InputType));
+ }
+
+ bool isDefinition() const {
+ return static_cast<ImportType>(Type) == ImportType::Definition;
+ }
+
+ bool isDeclaration() const {
+ return static_cast<ImportType>(Type) == ImportType::Declaration;
+ }
+};
+
/// Summary of memprof callsite metadata.
struct CallsiteInfo {
// Actual callee function.
diff --git a/llvm/include/llvm/Transforms/IPO/FunctionImport.h b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
index c4d19e8641eca2..9adc0c31eed439 100644
--- a/llvm/include/llvm/Transforms/IPO/FunctionImport.h
+++ b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
@@ -33,7 +33,14 @@ class FunctionImporter {
public:
/// Set of functions to import from a source module. Each entry is a set
/// containing all the GUIDs of all functions to import for a source module.
- using FunctionsToImportTy = std::unordered_set<GlobalValue::GUID>;
+ using FunctionsToImportTy = DenseMap<GlobalValue::GUID, SummaryImportInfo>;
+
+ // FIXME: Remove this.
+ enum ImportStatus {
+ NotImported,
+ ImportDeclaration,
+ ImportDefinition,
+ };
/// The different reasons selectCallee will chose not to import a
/// candidate.
@@ -99,8 +106,10 @@ class FunctionImporter {
/// index's module path string table).
using ImportMapTy = DenseMap<StringRef, FunctionsToImportTy>;
- /// The set contains an entry for every global value the module exports.
- using ExportSetTy = DenseSet<ValueInfo>;
+ /// The map contains an entry for every global value the module exports, the
+ /// key being the value info, and the value is the summary-based import info.
+ /// FIXME: Does this set need to be a map?
+ using ExportSetTy = DenseMap<ValueInfo, SummaryImportInfo>;
/// A function of this type is used to load modules referenced by the index.
using ModuleLoaderTy =
@@ -211,7 +220,8 @@ void gatherImportedSummariesForModule(
StringRef ModulePath,
const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries,
const FunctionImporter::ImportMapTy &ImportList,
- std::map<std::string, GVSummaryMapTy> &ModuleToSummariesForIndex);
+ std::map<std::string, GVSummaryMapTy> &ModuleToSummariesForIndex,
+ ModuleToGVSummaryPtrSet &ModuleToDecSummaries);
/// Emit into \p OutputFilename the files module \p ModulePath will import from.
std::error_code EmitImportsFiles(
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 53060df7f503e0..ace533fe28c92f 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -159,7 +159,7 @@ void llvm::computeLTOCacheKey(
std::vector<uint64_t> ExportsGUID;
ExportsGUID.reserve(ExportList.size());
for (const auto &VI : ExportList) {
- auto GUID = VI.getGUID();
+ auto GUID = VI.first.getGUID();
ExportsGUID.push_back(GUID);
}
@@ -205,7 +205,7 @@ void llvm::computeLTOCacheKey(
AddUint64(Entry.getFunctions().size());
for (auto &Fn : Entry.getFunctions())
- AddUint64(Fn);
+ AddUint64(Fn.first);
}
// Include the hash for the resolved ODR.
@@ -277,7 +277,7 @@ void llvm::computeLTOCacheKey(
for (const ImportModule &ImpM : ImportModulesVector)
for (auto &ImpF : ImpM.getFunctions()) {
GlobalValueSummary *S =
- Index.findSummaryInModule(ImpF, ImpM.getIdentifier());
+ Index.findSummaryInModule(ImpF.first, ImpM.getIdentifier());
AddUsedThings(S);
// If this is an alias, we also care about any types/etc. that the aliasee
// may reference.
@@ -1389,15 +1389,18 @@ class lto::ThinBackendProc {
llvm::StringRef ModulePath,
const std::string &NewModulePath) {
std::map<std::string, GVSummaryMapTy> ModuleToSummariesForIndex;
+ ModuleToGVSummaryPtrSet ModuleToDeclarationSummaries;
std::error_code EC;
gatherImportedSummariesForModule(ModulePath, ModuleToDefinedGVSummaries,
- ImportList, ModuleToSummariesForIndex);
+ ImportList, ModuleToSummariesForIndex,
+ ModuleToDeclarationSummaries);
raw_fd_ostream OS(NewModulePath + ".thinlto.bc", EC,
sys::fs::OpenFlags::OF_None);
if (EC)
return errorCodeToError(EC);
- writeIndexToFile(CombinedIndex, OS, &ModuleToSummariesForIndex);
+ writeIndexToFile(CombinedIndex, OS, &ModuleToSummariesForIndex,
+ &ModuleToDeclarationSummaries);
if (ShouldEmitImportsFiles) {
EC = EmitImportsFiles(ModulePath, NewModulePath + ".imports",
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 71e8849dc3cc91..6bb514d3d24e70 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -716,7 +716,10 @@ bool lto::initImportList(const Module &M,
if (Summary->modulePath() == M.getModuleIdentifier())
continue;
// Add an entry to provoke importing by thinBackend.
- ImportList[Summary->modulePath()].insert(GUID);
+ ImportList[Summary->modulePath()][GUID].updateType(
+ Summary->flags().ImportAsDec
+ ? SummaryImportInfo::ImportType::Declaration
+ : SummaryImportInfo::ImportType::Definition);
}
}
return true;
diff --git a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
index 8f517eb50dc76f..75aecc95e789fc 100644
--- a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -794,9 +794,11 @@ void ThinLTOCodeGenerator::gatherImportedSummariesForModule(
IsPrevailing(PrevailingCopy), ImportLists,
ExportLists);
+ ModuleToGVSummaryPtrSet ModuleToDecSummaries;
llvm::gatherImportedSummariesForModule(
ModuleIdentifier, ModuleToDefinedGVSummaries,
- ImportLists[ModuleIdentifier], ModuleToSummariesForIndex);
+ ImportLists[ModuleIdentifier], ModuleToSummariesForIndex,
+ ModuleToDecSummaries);
}
/**
@@ -833,9 +835,12 @@ void ThinLTOCodeGenerator::emitImports(Module &TheModule, StringRef OutputName,
ExportLists);
std::map<std::string, GVSummaryMapTy> ModuleToSummariesForIndex;
+ // FIXME: Pass on `ModuleToDecSummaries` to `EmitImportFiles` below.
+ ModuleToGVSummaryPtrSet ModuleToDecSummaries;
llvm::gatherImportedSummariesForModule(
ModuleIdentifier, ModuleToDefinedGVSummaries,
- ImportLists[ModuleIdentifier], ModuleToSummariesForIndex);
+ ImportLists[ModuleIdentifier], ModuleToSummariesForIndex,
+ ModuleToDecSummaries);
std::error_code EC;
if ((EC = EmitImportsFiles(ModuleIdentifier, OutputName,
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 68f9799616ae6d..042fc285128b14 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -358,17 +358,23 @@ class GlobalsImporter final {
if (!GVS || !Index.canImportGlobalVar(GVS, /* AnalyzeRefs */ true) ||
LocalNotInModule(GVS))
continue;
- auto ILI = ImportList[RefSummary->modulePath()].insert(VI.getGUID());
+ auto [Iter, Inserted] =
+ ImportList[RefSummary->modulePath()].try_emplace(
+ VI.getGUID(),
+ SummaryImportInfo(SummaryImportInfo::ImportType::Definition));
// Only update stat and exports if we haven't already imported this
// variable.
- if (!ILI.second)
+ if (!Inserted) {
+ Iter->second.updateType(SummaryImportInfo::ImportType::Definition);
break;
+ }
NumImportedGlobalVarsThinLink++;
// Any references made by this variable will be marked exported
// later, in ComputeCrossModuleImport, after import decisions are
// complete, which is more efficient than adding them here.
if (ExportLists)
- (*ExportLists)[RefSummary->modulePath()].insert(VI);
+ (*ExportLists)[RefSummary->modulePath()][VI].updateType(
+ SummaryImportInfo::ImportType::Definition);
// If variable is not writeonly we attempt to recursively analyze
// its references in order to import referenced constants.
@@ -545,10 +551,12 @@ class WorkloadImportsManager : public ModuleImportsManager {
LLVM_DEBUG(dbgs() << "[Workload][Including]" << VI.name() << " from "
<< ExportingModule << " : "
<< Function::getGUID(VI.name()) << "\n");
- ImportList[ExportingModule].insert(VI.getGUID());
+ ImportList[ExportingModule][VI.getGUID()].updateType(
+ SummaryImportInfo::ImportType::Definition);
GVI.onImportingSummary(*GVS);
if (ExportLists)
- (*ExportLists)[ExportingModule].insert(VI);
+ (*ExportLists)[ExportingModule][VI].updateType(
+ SummaryImportInfo::ImportType::Definition);
}
LLVM_DEBUG(dbgs() << "[Workload] Done\n");
}
@@ -816,23 +824,27 @@ static void computeImportForFunction(
"selectCallee() didn't honor the threshold");
auto ExportModulePath = ResolvedCalleeSummary->modulePath();
- auto ILI = ImportList[ExportModulePath].insert(VI.getGUID());
+ auto [Iter, Inserted] =
+ ImportList[ExportModulePath].insert(std::make_pair(
+ VI.getGUID(),
+ SummaryImportInfo(SummaryImportInfo::ImportType::Definition)));
// We previously decided to import this GUID definition if it was already
// inserted in the set of imports from the exporting module.
- bool PreviouslyImported = !ILI.second;
- if (!PreviouslyImported) {
+ if (Inserted) {
NumImportedFunctionsThinLink++;
if (IsHotCallsite)
NumImportedHotFunctionsThinLink++;
if (IsCriticalCallsite)
NumImportedCriticalFunctionsThinLink++;
- }
+ } else
+ Iter->second.updateType(SummaryImportInfo::ImportType::Definition);
// Any calls/references made by this function will be marked exported
// later, in ComputeCrossModuleImport, after import decisions are
// complete, which is more efficient than adding them here.
if (ExportLists)
- (*ExportLists)[ExportModulePath].insert(VI);
+ (*ExportLists)[ExportModulePath][VI].updateType(
+ SummaryImportInfo::ImportType::Definition);
}
auto GetAdjustedThreshold = [](unsigned Threshold, bool IsHotCallsite) {
@@ -942,9 +954,11 @@ template <class T>
static unsigned numGlobalVarSummaries(const ModuleSummaryIndex &Index,
T &Cont) {
unsigned NumGVS = 0;
- for (auto &V : Cont)
- if (isGlobalVarSummary(Index, V))
+ for (auto &[GUID, Type] : Cont) {
+ assert(Type.isDefinition() && "Declaration type doesn't exist yet");
+ if (isGlobalVarSummary(Index, GUID))
++NumGVS;
+ }
return NumGVS;
}
#endif
@@ -959,8 +973,8 @@ static bool checkVariableImport(
for (auto &ImportPerModule : ImportLists)
for (auto &ExportPerModule : ImportPerModule.second)
- FlattenedImports.insert(ExportPerModule.second.begin(),
- ExportPerModule.second.end());
+ for (auto &[GUID, Type] : ExportPerModule.second)
+ FlattenedImports.insert(GUID);
// Checks that all GUIDs of read/writeonly vars we see in export lists
// are also in the import lists. Otherwise we my face linker undefs,
@@ -979,7 +993,7 @@ static bool checkVariableImport(
};
for (auto &ExportPerModule : ExportLists)
- for (auto &VI : ExportPerModule.second)
+ for (auto &[VI, Unused] : ExportPerModule.second)
if (!FlattenedImports.count(VI.getGUID()) &&
IsReadOrWriteOnlyVarNeedingImporting(ExportPerModule.first, VI))
return false;
@@ -1015,7 +1029,8 @@ void llvm::ComputeCrossModuleImport(
FunctionImporter::ExportSetTy NewExports;
const auto &DefinedGVSummaries =
ModuleToDefinedGVSummaries.lookup(ELI.first);
- for (auto &EI : ELI.second) {
+ for (auto &[EI, Type] : ELI.second) {
+ assert(Type.isDefinition() && "Declaration type doesn't exist yet");
// Find the copy defined in the exporting module so that we can mark the
// values it references in that specific definition as exported.
// Below we will add all references and called values, without regard to
@@ -1035,13 +1050,16 @@ void llvm::ComputeCrossModuleImport(
// See processGlobalForThinLTO.
if (!Index.isWriteOnly(GVS))
for (const auto &VI : GVS->refs())
- NewExports.insert(VI);
+ NewExports[VI].updateType(
+ SummaryImportInfo::ImportType::Declaration);
} else {
auto *FS = cast<FunctionSummary>(S);
for (const auto &Edge : FS->calls())
- NewExports.insert(Edge.first);
+ NewExports[Edge.first].updateType(
+ SummaryImportInfo::ImportType::Declaration);
for (const auto &Ref : FS->refs())
- NewExports.insert(Ref);
+ NewExports[Ref].updateType(
+ SummaryImportInfo::ImportType::Declaration);
}
}
// Prune list computed above to only include values defined in the exporting
@@ -1049,7 +1067,7 @@ void llvm::ComputeCrossModuleImport(
// ref/call target multiple times in above loop, and it is more efficient to
// avoid a set lookup each time.
for (auto EI = NewExports.begin(); EI != NewExports.end();) {
- if (!DefinedGVSummaries.count(EI->getGUID()))
+ if (!DefinedGVSummaries.count(EI->first.getGUID()))
NewExports.erase(EI++);
else
++EI;
@@ -1149,7 +1167,10 @@ static void ComputeCrossModuleImportForModuleFromIndexForTest(
if (Summary->modulePath() == ModulePath)
continue;
// Add an entry to provoke importing by thinBackend.
- ImportList[Summary->modulePath()].insert(GUID);
+ ImportList[Summary->modulePath()][GUID].updateType(
+ Summary->flags().ImportAsDec
+ ? SummaryImportInfo::ImportType::Declaration
+ : SummaryImportInfo::ImportType::Definition);
}
#ifndef NDEBUG
dumpImportListForModule(Index, ModulePath, ImportList);
@@ -1332,20 +1353,25 @@ void llvm::gatherImportedSummariesForModule(
StringRef ModulePath,
const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries,
const FunctionImporter::ImportMapTy &ImportList,
- std::map<std::string, GVSummaryMapTy> &ModuleToSummariesForIndex) {
+ std::map<std::string, GVSummaryMapTy> &ModuleToSummariesForIndex,
+ ModuleToGVSummaryPtrSet &ModuleToDecSummaries) {
// Include all summaries from the importing module.
ModuleToSummariesForIndex[std::string(ModulePath)] =
ModuleToDefinedGVSummaries.lookup(ModulePath);
// Include summaries for imports.
for (const auto &ILI : ImportList) {
- auto &SummariesForIndex = ModuleToSummariesForIndex[std::string(ILI.first)];
+ std::string ModulePath(ILI.first);
+ auto &SummariesForIndex = ModuleToSummariesForIndex[ModulePath];
+ auto &DecSummaries = ModuleToDecSummaries[ModulePath];
const auto &DefinedGVSummaries =
ModuleToDefinedGVSummaries.lookup(ILI.first);
- for (const auto &GI : ILI.second) {
- const auto &DS = DefinedGVSummaries.find(GI);
+ for (const auto &[GUID, Type] : ILI.second) {
+ const auto &DS = DefinedGVSummaries.find(GUID);
assert(DS != DefinedGVSummaries.end() &&
"Expected a defined summary for imported global value");
- SummariesForIndex[GI] = DS->second;
+ SummariesForIndex[GUID] = DS->second;
+ if (Type.isDeclaration())
+ DecSummaries.insert(DS->second);
}
}
}
@@ -1617,6 +1643,16 @@ Expected<bool> FunctionImporter::importFunctions(
for (const auto &FunctionsToImportPerModule : ImportList) {
ModuleNameOrderedList.insert(FunctionsToImportPerModule.first);
}
+
+ auto getImportStatus = [&](const FunctionsToImportTy &GUIDToImportType,
+ GlobalValue::GUID GUID) -> ImportStatus {
+ auto Iter = GUIDToImportType.find(GUID);
+ if (Iter == GUIDToImportType.end())
+ return ImportStatus::NotImported;
+ return Iter->second.isDefinition() ? ImportStatus::ImportDefinition
+ : ImportStatus::ImportDeclaration;
+ };
+
for (const auto &Name : ModuleNameOrderedList) {
// Get the module for the import
const auto &FunctionsToImportPerModule = ImportList.find(Name);
@@ -1634,17 +1670,21 @@ Expected<bool> FunctionImporter::importFunctions(
return std::move(Err);
auto &ImportGUIDs = FunctionsToImportPerModule->second;
+
// Find the globals to import
SetVector<GlobalValue *> GlobalsToImport;
+ SetVector<GlobalValue *> GlobalDeclsToImport;
for (Function &F : *SrcModule) {
if (!F.hasName())
continue;
auto GUID = F.getGUID();
- auto Import = ImportGUIDs.count(GUID);
- LLVM_DEBUG(dbgs() << (Import ? "Is" : "Not") << " importing function "
- << GUID << " " << F.getName() << " from "
- << SrcModule->getSourceFileName() << "\n");
- if (Import) {
+ auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ const bool ImportDefinition =
+ ImportStatus == ImportStatus::ImportDefinition;
+ LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
+ << " importing function " << GUID << " " << F.getName()
+ << " from " << SrcModule->getSourceFileName() << "\n");
+ if (ImportDefinition) {
if (Error Err = F.materialize())
return std::move(Err);
// MemProf should match function's definition and summary,
@@ -1664,17 +1704,20 @@ Expected<bool> FunctionImporter::importFunctions(
SrcModule->getSourceFileName())}));
}
GlobalsToImport.insert(&F);
- }
+ } else if (ImportStatus == ImportDeclaration)
+ GlobalDeclsToImport.insert(&F);
}
for (GlobalVariable &GV : SrcModule->globals()) {
if (!GV.hasName())
continue;
auto GUID = GV.getGUID();
- auto Import = ImportGUIDs.count(GUID);
- LLVM_DEBUG(dbgs() << (Import ? "Is" : "Not") << " importing global "
- << GUID << " " << GV.getName() << " from "
- << SrcModule->getSourceFileName() << "\n");
- if (Import) {
+ auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ const bool ImportDefinition =
+ (ImportStatus == ImportStatus::ImportDefinition);
+ LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
+ << " importing global " << GUID << " " << GV.getName()
+ << " from " << SrcModule->getSourceFileName() << "\n");
+ if (ImportDefinition) {
if (Error Err = GV.materialize())
return std::move(Err);
ImportedGVCount += GlobalsToImport.insert(&GV);
@@ -1684,11 +1727,13 @@ Expected<bool> FunctionImporter::importFunctions(
if (!GA.hasName() || isa<GlobalIFunc>(GA.getAliaseeObject()))
continue;
auto GUID = GA.getGUID();
- auto Import = ImportGUIDs.count(GUID);
- LLVM_DEBUG(dbgs() << (Import ? "Is" : "Not") << " importing alias "
- << GUID << " " << GA.getName() << " from "
- << SrcModule->getSourceFileName() << "\n");
- if (Import) {
+ auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ const bool ImportDefinition =
+ (ImportStatus == ImportStatus::ImportDefinition);
+ LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
+ << " importing alias " << GUID << " " << GA.getName()
+ << " from " << SrcModule->getSourceFileName() << "\n");
+ if (ImportDefinition) {
if (Error Err = GA.materialize())
return std::move(Err);
// Import alias as a copy of its aliasee.
@@ -1738,6 +1783,7 @@ Expected<bool> FunctionImporter::importFunctions(
<< " from " << SrcModule->getSourceFileName() << "\n";
}
+ // FIXME: A later change will pass on GlobalDeclsToImport to IRMover.
if (Error Err = Mover.move(std::move(SrcModule),
GlobalsToImport.getArrayRef(), nullptr,
/*IsPerformingImport=*/true))
diff --git a/llvm/tools/llvm-link/llvm-link.cpp b/llvm/tools/llvm-link/llvm-link.cpp
index 9049cb5e858002..0a60b1e3d8f5d2 100644
--- a/llvm/tools/llvm-link/llvm-link.cpp
+++ b/llvm/tools/llvm-link/llvm-link.cpp
@@ -376,7 +376,7 @@ static bool importFunctions(const char *argv0, Module &DestModule) {
auto &Entry =
ImportList[FileNameStringCache.insert(FileName).first->getKey()];
- Entry.insert(F->getGUID());
+ Entry[F->getGUID()].updateType(SummaryImportInfo::ImportType::Definition);
}
auto CachedModuleLoader = [&](StringRef Identifier) {
return ModuleLoaderCache.takeModule(std::string(Identifier));
>From 23a3fa4d3d124a2525f20e3a58da6d5e7740e7df Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Tue, 16 Apr 2024 21:12:34 -0700
Subject: [PATCH 2/5] simplify code
---
llvm/include/llvm/IR/ModuleSummaryIndex.h | 30 ++-----
.../llvm/Transforms/IPO/FunctionImport.h | 16 ++--
llvm/lib/LTO/LTOBackend.cpp | 10 ++-
llvm/lib/Transforms/IPO/FunctionImport.cpp | 90 +++++++++----------
llvm/tools/llvm-link/llvm-link.cpp | 2 +-
5 files changed, 62 insertions(+), 86 deletions(-)
diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
index 7f6f7446e09620..29d13cf4f4fae6 100644
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -296,30 +296,6 @@ template <> struct DenseMapInfo<ValueInfo> {
static unsigned getHashValue(ValueInfo I) { return (uintptr_t)I.getRef(); }
};
-struct SummaryImportInfo {
- enum class ImportType : uint8_t {
- NotImported = 0,
- Declaration = 1,
- Definition = 2,
- };
- unsigned Type : 3;
- SummaryImportInfo() : Type(static_cast<unsigned>(ImportType::NotImported)) {}
- SummaryImportInfo(ImportType Type) : Type(static_cast<unsigned>(Type)) {}
-
- // FIXME: delete the first two set* helper function.
- void updateType(ImportType InputType) {
- Type = std::max(Type, static_cast<unsigned>(InputType));
- }
-
- bool isDefinition() const {
- return static_cast<ImportType>(Type) == ImportType::Definition;
- }
-
- bool isDeclaration() const {
- return static_cast<ImportType>(Type) == ImportType::Declaration;
- }
-};
-
/// Summary of memprof callsite metadata.
struct CallsiteInfo {
// Actual callee function.
@@ -609,7 +585,11 @@ class GlobalValueSummary {
return Flags.ImportType == GlobalValueSummary::ImportKind::Declaration;
}
- void setImportKind(ImportKind IK) { Flags.ImportType = IK; }
+ GlobalValueSummary::ImportKind importType() const {
+ return static_cast<ImportKind>(Flags.ImportType);
+ }
+
+ void setImportType(ImportKind IK) { Flags.ImportType = IK; }
GlobalValue::VisibilityTypes getVisibility() const {
return (GlobalValue::VisibilityTypes)Flags.Visibility;
diff --git a/llvm/include/llvm/Transforms/IPO/FunctionImport.h b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
index 9adc0c31eed439..6729fcc420a6ed 100644
--- a/llvm/include/llvm/Transforms/IPO/FunctionImport.h
+++ b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
@@ -33,14 +33,8 @@ class FunctionImporter {
public:
/// Set of functions to import from a source module. Each entry is a set
/// containing all the GUIDs of all functions to import for a source module.
- using FunctionsToImportTy = DenseMap<GlobalValue::GUID, SummaryImportInfo>;
-
- // FIXME: Remove this.
- enum ImportStatus {
- NotImported,
- ImportDeclaration,
- ImportDefinition,
- };
+ using FunctionsToImportTy =
+ DenseMap<GlobalValue::GUID, GlobalValueSummary::ImportKind>;
/// The different reasons selectCallee will chose not to import a
/// candidate.
@@ -107,9 +101,9 @@ class FunctionImporter {
using ImportMapTy = DenseMap<StringRef, FunctionsToImportTy>;
/// The map contains an entry for every global value the module exports, the
- /// key being the value info, and the value is the summary-based import info.
- /// FIXME: Does this set need to be a map?
- using ExportSetTy = DenseMap<ValueInfo, SummaryImportInfo>;
+ /// key being the value info, and the value indicates whether the definition
+ /// or declaration is visible to another module.
+ using ExportSetTy = DenseMap<ValueInfo, GlobalValueSummary::ImportKind>;
/// A function of this type is used to load modules referenced by the index.
using ModuleLoaderTy =
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 6bb514d3d24e70..23d75c238fc296 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -715,11 +715,13 @@ bool lto::initImportList(const Module &M,
// e.g. record required linkage changes.
if (Summary->modulePath() == M.getModuleIdentifier())
continue;
+
// Add an entry to provoke importing by thinBackend.
- ImportList[Summary->modulePath()][GUID].updateType(
- Summary->flags().ImportAsDec
- ? SummaryImportInfo::ImportType::Declaration
- : SummaryImportInfo::ImportType::Definition);
+ auto [Iter, Inserted] = ImportList[Summary->modulePath()].try_emplace(
+ GUID, Summary->importType());
+
+ if (!Inserted)
+ Iter->second = std::min(Iter->second, Summary->importType());
}
}
return true;
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 042fc285128b14..1485259e642a04 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -358,14 +358,14 @@ class GlobalsImporter final {
if (!GVS || !Index.canImportGlobalVar(GVS, /* AnalyzeRefs */ true) ||
LocalNotInModule(GVS))
continue;
+
auto [Iter, Inserted] =
ImportList[RefSummary->modulePath()].try_emplace(
- VI.getGUID(),
- SummaryImportInfo(SummaryImportInfo::ImportType::Definition));
+ VI.getGUID(), GlobalValueSummary::Definition);
// Only update stat and exports if we haven't already imported this
// variable.
if (!Inserted) {
- Iter->second.updateType(SummaryImportInfo::ImportType::Definition);
+ Iter->second = std::min(GlobalValueSummary::Definition, Iter->second);
break;
}
NumImportedGlobalVarsThinLink++;
@@ -373,8 +373,8 @@ class GlobalsImporter final {
// later, in ComputeCrossModuleImport, after import decisions are
// complete, which is more efficient than adding them here.
if (ExportLists)
- (*ExportLists)[RefSummary->modulePath()][VI].updateType(
- SummaryImportInfo::ImportType::Definition);
+ (*ExportLists)[RefSummary->modulePath()][VI] =
+ GlobalValueSummary::Definition;
// If variable is not writeonly we attempt to recursively analyze
// its references in order to import referenced constants.
@@ -551,12 +551,11 @@ class WorkloadImportsManager : public ModuleImportsManager {
LLVM_DEBUG(dbgs() << "[Workload][Including]" << VI.name() << " from "
<< ExportingModule << " : "
<< Function::getGUID(VI.name()) << "\n");
- ImportList[ExportingModule][VI.getGUID()].updateType(
- SummaryImportInfo::ImportType::Definition);
+ ImportList[ExportingModule][VI.getGUID()] =
+ GlobalValueSummary::Definition;
GVI.onImportingSummary(*GVS);
if (ExportLists)
- (*ExportLists)[ExportingModule][VI].updateType(
- SummaryImportInfo::ImportType::Definition);
+ (*ExportLists)[ExportingModule][VI] = GlobalValueSummary::Definition;
}
LLVM_DEBUG(dbgs() << "[Workload] Done\n");
}
@@ -824,10 +823,8 @@ static void computeImportForFunction(
"selectCallee() didn't honor the threshold");
auto ExportModulePath = ResolvedCalleeSummary->modulePath();
- auto [Iter, Inserted] =
- ImportList[ExportModulePath].insert(std::make_pair(
- VI.getGUID(),
- SummaryImportInfo(SummaryImportInfo::ImportType::Definition)));
+ auto [Iter, Inserted] = ImportList[ExportModulePath].insert(
+ std::make_pair(VI.getGUID(), GlobalValueSummary::Definition));
// We previously decided to import this GUID definition if it was already
// inserted in the set of imports from the exporting module.
if (Inserted) {
@@ -837,14 +834,13 @@ static void computeImportForFunction(
if (IsCriticalCallsite)
NumImportedCriticalFunctionsThinLink++;
} else
- Iter->second.updateType(SummaryImportInfo::ImportType::Definition);
+ Iter->second = GlobalValueSummary::Definition;
// Any calls/references made by this function will be marked exported
// later, in ComputeCrossModuleImport, after import decisions are
// complete, which is more efficient than adding them here.
if (ExportLists)
- (*ExportLists)[ExportModulePath][VI].updateType(
- SummaryImportInfo::ImportType::Definition);
+ (*ExportLists)[ExportModulePath][VI] = GlobalValueSummary::Definition;
}
auto GetAdjustedThreshold = [](unsigned Threshold, bool IsHotCallsite) {
@@ -955,7 +951,8 @@ static unsigned numGlobalVarSummaries(const ModuleSummaryIndex &Index,
T &Cont) {
unsigned NumGVS = 0;
for (auto &[GUID, Type] : Cont) {
- assert(Type.isDefinition() && "Declaration type doesn't exist yet");
+ assert(Type == GlobalValueSummary::Definition &&
+ "Declaration type doesn't exist yet");
if (isGlobalVarSummary(Index, GUID))
++NumGVS;
}
@@ -1030,7 +1027,8 @@ void llvm::ComputeCrossModuleImport(
const auto &DefinedGVSummaries =
ModuleToDefinedGVSummaries.lookup(ELI.first);
for (auto &[EI, Type] : ELI.second) {
- assert(Type.isDefinition() && "Declaration type doesn't exist yet");
+ assert(Type == GlobalValueSummary::Definition &&
+ "Declaration type doesn't exist yet");
// Find the copy defined in the exporting module so that we can mark the
// values it references in that specific definition as exported.
// Below we will add all references and called values, without regard to
@@ -1049,17 +1047,15 @@ void llvm::ComputeCrossModuleImport(
// we convert such variables initializers to "zeroinitializer".
// See processGlobalForThinLTO.
if (!Index.isWriteOnly(GVS))
- for (const auto &VI : GVS->refs())
- NewExports[VI].updateType(
- SummaryImportInfo::ImportType::Declaration);
+ for (const auto &VI : GVS->refs()) {
+ NewExports.try_emplace(VI, GlobalValueSummary::Declaration);
+ }
} else {
auto *FS = cast<FunctionSummary>(S);
for (const auto &Edge : FS->calls())
- NewExports[Edge.first].updateType(
- SummaryImportInfo::ImportType::Declaration);
+ NewExports.try_emplace(Edge.first, GlobalValueSummary::Declaration);
for (const auto &Ref : FS->refs())
- NewExports[Ref].updateType(
- SummaryImportInfo::ImportType::Declaration);
+ NewExports.try_emplace(Ref, GlobalValueSummary::Declaration);
}
}
// Prune list computed above to only include values defined in the exporting
@@ -1167,10 +1163,10 @@ static void ComputeCrossModuleImportForModuleFromIndexForTest(
if (Summary->modulePath() == ModulePath)
continue;
// Add an entry to provoke importing by thinBackend.
- ImportList[Summary->modulePath()][GUID].updateType(
- Summary->flags().ImportAsDec
- ? SummaryImportInfo::ImportType::Declaration
- : SummaryImportInfo::ImportType::Definition);
+ auto [Iter, Inserted] = ImportList[Summary->modulePath()].try_emplace(
+ GUID, Summary->importType());
+ if (!Inserted)
+ Iter->second = std::min(Iter->second, Summary->importType());
}
#ifndef NDEBUG
dumpImportListForModule(Index, ModulePath, ImportList);
@@ -1370,7 +1366,7 @@ void llvm::gatherImportedSummariesForModule(
assert(DS != DefinedGVSummaries.end() &&
"Expected a defined summary for imported global value");
SummariesForIndex[GUID] = DS->second;
- if (Type.isDeclaration())
+ if (Type == GlobalValueSummary::Declaration)
DecSummaries.insert(DS->second);
}
}
@@ -1644,13 +1640,13 @@ Expected<bool> FunctionImporter::importFunctions(
ModuleNameOrderedList.insert(FunctionsToImportPerModule.first);
}
- auto getImportStatus = [&](const FunctionsToImportTy &GUIDToImportType,
- GlobalValue::GUID GUID) -> ImportStatus {
+ auto maybeGetImportType = [&](const FunctionsToImportTy &GUIDToImportType,
+ GlobalValue::GUID GUID)
+ -> std::optional<GlobalValueSummary::ImportKind> {
auto Iter = GUIDToImportType.find(GUID);
if (Iter == GUIDToImportType.end())
- return ImportStatus::NotImported;
- return Iter->second.isDefinition() ? ImportStatus::ImportDefinition
- : ImportStatus::ImportDeclaration;
+ return std::nullopt;
+ return Iter->second;
};
for (const auto &Name : ModuleNameOrderedList) {
@@ -1673,14 +1669,15 @@ Expected<bool> FunctionImporter::importFunctions(
// Find the globals to import
SetVector<GlobalValue *> GlobalsToImport;
- SetVector<GlobalValue *> GlobalDeclsToImport;
for (Function &F : *SrcModule) {
if (!F.hasName())
continue;
auto GUID = F.getGUID();
- auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ auto ImportType = maybeGetImportType(ImportGUIDs, GUID);
+ if (!ImportType)
+ continue;
const bool ImportDefinition =
- ImportStatus == ImportStatus::ImportDefinition;
+ *ImportType == GlobalValueSummary::Definition;
LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
<< " importing function " << GUID << " " << F.getName()
<< " from " << SrcModule->getSourceFileName() << "\n");
@@ -1704,16 +1701,17 @@ Expected<bool> FunctionImporter::importFunctions(
SrcModule->getSourceFileName())}));
}
GlobalsToImport.insert(&F);
- } else if (ImportStatus == ImportDeclaration)
- GlobalDeclsToImport.insert(&F);
+ }
}
for (GlobalVariable &GV : SrcModule->globals()) {
if (!GV.hasName())
continue;
auto GUID = GV.getGUID();
- auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ auto ImportType = maybeGetImportType(ImportGUIDs, GUID);
+ if (!ImportType)
+ continue;
const bool ImportDefinition =
- (ImportStatus == ImportStatus::ImportDefinition);
+ (*ImportType == GlobalValueSummary::Definition);
LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
<< " importing global " << GUID << " " << GV.getName()
<< " from " << SrcModule->getSourceFileName() << "\n");
@@ -1727,9 +1725,12 @@ Expected<bool> FunctionImporter::importFunctions(
if (!GA.hasName() || isa<GlobalIFunc>(GA.getAliaseeObject()))
continue;
auto GUID = GA.getGUID();
- auto ImportStatus = getImportStatus(ImportGUIDs, GUID);
+ auto ImportType = maybeGetImportType(ImportGUIDs, GUID);
+ if (!ImportType)
+ continue;
+
const bool ImportDefinition =
- (ImportStatus == ImportStatus::ImportDefinition);
+ (*ImportType == GlobalValueSummary::Definition);
LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
<< " importing alias " << GUID << " " << GA.getName()
<< " from " << SrcModule->getSourceFileName() << "\n");
@@ -1783,7 +1784,6 @@ Expected<bool> FunctionImporter::importFunctions(
<< " from " << SrcModule->getSourceFileName() << "\n";
}
- // FIXME: A later change will pass on GlobalDeclsToImport to IRMover.
if (Error Err = Mover.move(std::move(SrcModule),
GlobalsToImport.getArrayRef(), nullptr,
/*IsPerformingImport=*/true))
diff --git a/llvm/tools/llvm-link/llvm-link.cpp b/llvm/tools/llvm-link/llvm-link.cpp
index 9e28b3a217f8b0..a6bee02b1302d3 100644
--- a/llvm/tools/llvm-link/llvm-link.cpp
+++ b/llvm/tools/llvm-link/llvm-link.cpp
@@ -377,7 +377,7 @@ static bool importFunctions(const char *argv0, Module &DestModule) {
auto &Entry =
ImportList[FileNameStringCache.insert(FileName).first->getKey()];
- Entry[F->getGUID()].updateType(SummaryImportInfo::ImportType::Definition);
+ Entry[F->getGUID()] = GlobalValueSummary::Definition;
}
auto CachedModuleLoader = [&](StringRef Identifier) {
return ModuleLoaderCache.takeModule(std::string(Identifier));
>From a0277b43faf515c3aa21b290c09e51501fa796ac Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Tue, 16 Apr 2024 23:44:18 -0700
Subject: [PATCH 3/5] Flag gate the import-declaration change.
---
.../llvm/Transforms/IPO/FunctionImport.h | 3 +-
llvm/lib/Transforms/IPO/FunctionImport.cpp | 55 +++++++++++++++++--
2 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/llvm/include/llvm/Transforms/IPO/FunctionImport.h b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
index 6729fcc420a6ed..fcf51ed5a4eddd 100644
--- a/llvm/include/llvm/Transforms/IPO/FunctionImport.h
+++ b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
@@ -31,8 +31,7 @@ class Module;
/// based on the provided summary informations.
class FunctionImporter {
public:
- /// Set of functions to import from a source module. Each entry is a set
- /// containing all the GUIDs of all functions to import for a source module.
+ /// The functions to import from a source module and their import type.
using FunctionsToImportTy =
DenseMap<GlobalValue::GUID, GlobalValueSummary::ImportKind>;
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 1485259e642a04..eb0bf36ab26d1f 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -140,6 +140,16 @@ static cl::opt<bool>
ImportAllIndex("import-all-index",
cl::desc("Import all external functions in index."));
+/// Test-only option.
+/// TODO: Implement selective import (based on combined summary analysis) to
+/// ensure the imported function has a use case in the postlink pipeline.
+/// Import each function declaration as a fallback in real build may grow map
+/// size unnecessarily in the indexing step.
+static cl::opt<bool> ImportDeclaration(
+ "import-declaration", cl::init(false), cl::Hidden,
+ cl::desc("If true, import function declaration as fallback if the function "
+ "definition is not imported."));
+
/// Pass a workload description file - an example of workload would be the
/// functions executed to satisfy a RPC request. A workload is defined by a root
/// function and the list of functions that are (frequently) needed to satisfy
@@ -245,8 +255,10 @@ static auto qualifyCalleeCandidates(
}
/// Given a list of possible callee implementation for a call site, select one
-/// that fits the \p Threshold. If none are found, the Reason will give the last
-/// reason for the failure (last, in the order of CalleeSummaryList entries).
+/// that fits the \p Threshold for function definition import. If none are
+/// found, the Reason will give the last reason for the failure (last, in the
+/// order of CalleeSummaryList entries). If caller wants to select eligible
+/// summary
///
/// FIXME: select "best" instead of first that fits. But what is "best"?
/// - The smallest: more likely to be inlined.
@@ -259,24 +271,32 @@ static const GlobalValueSummary *
selectCallee(const ModuleSummaryIndex &Index,
ArrayRef<std::unique_ptr<GlobalValueSummary>> CalleeSummaryList,
unsigned Threshold, StringRef CallerModulePath,
+ const GlobalValueSummary *&TooLargeOrNoInlineSummary,
FunctionImporter::ImportFailureReason &Reason) {
+ // Records the last summary with reason noinline or too-large.
+ TooLargeOrNoInlineSummary = nullptr;
auto QualifiedCandidates =
qualifyCalleeCandidates(Index, CalleeSummaryList, CallerModulePath);
for (auto QualifiedValue : QualifiedCandidates) {
Reason = QualifiedValue.first;
+ // Skip a summary if its import is not (proved to be) legal.
if (Reason != FunctionImporter::ImportFailureReason::None)
continue;
auto *Summary =
cast<FunctionSummary>(QualifiedValue.second->getBaseObject());
+ // Don't bother importing the definition if the chance of inlining it is
+ // not high enough (except under `--force-import-all`).
if ((Summary->instCount() > Threshold) && !Summary->fflags().AlwaysInline &&
!ForceImportAll) {
+ TooLargeOrNoInlineSummary = Summary;
Reason = FunctionImporter::ImportFailureReason::TooLarge;
continue;
}
- // Don't bother importing if we can't inline it anyway.
+ // Don't bother importing the definition if we can't inline it anyway.
if (Summary->fflags().NoInline && !ForceImportAll) {
+ TooLargeOrNoInlineSummary = Summary;
Reason = FunctionImporter::ImportFailureReason::NoInline;
continue;
}
@@ -359,12 +379,17 @@ class GlobalsImporter final {
LocalNotInModule(GVS))
continue;
+ // If there isn't an entry for GUID, insert <GUID, Definition> pair.
+ // Otherwise, definition should take precedence over declaration.
auto [Iter, Inserted] =
ImportList[RefSummary->modulePath()].try_emplace(
VI.getGUID(), GlobalValueSummary::Definition);
// Only update stat and exports if we haven't already imported this
// variable.
if (!Inserted) {
+ // FIXME: Introduce a wrapper struct around ImportType, and provide
+ // an `updateType` method for better readability, just like how we
+ // update the hotness of a call edge.
Iter->second = std::min(GlobalValueSummary::Definition, Iter->second);
break;
}
@@ -776,9 +801,28 @@ static void computeImportForFunction(
}
FunctionImporter::ImportFailureReason Reason{};
- CalleeSummary = selectCallee(Index, VI.getSummaryList(), NewThreshold,
- Summary.modulePath(), Reason);
+
+ // `SummaryForDeclImport` is an summary eligible for declaration import.
+ const GlobalValueSummary *SummaryForDeclImport = nullptr;
+ CalleeSummary =
+ selectCallee(Index, VI.getSummaryList(), NewThreshold,
+ Summary.modulePath(), SummaryForDeclImport, Reason);
if (!CalleeSummary) {
+ // There isn't a callee for definition import but one for declaration
+ // import.
+ if (ImportDeclaration && SummaryForDeclImport) {
+ StringRef DeclSourceModule = SummaryForDeclImport->modulePath();
+
+ // Since definition takes precedence over declaration for the same VI,
+ // try emplace <VI, declaration> pair without checking insert result.
+ // If insert doesn't happen, there must be an existing entry keyed by
+ // VI.
+ if (ExportLists)
+ (*ExportLists)[DeclSourceModule].try_emplace(
+ VI, GlobalValueSummary::Declaration);
+ ImportList[DeclSourceModule].try_emplace(
+ VI.getGUID(), GlobalValueSummary::Declaration);
+ }
// Update with new larger threshold if this was a retry (otherwise
// we would have already inserted with NewThreshold above). Also
// update failure info if requested.
@@ -798,6 +842,7 @@ static void computeImportForFunction(
FailureInfo = std::make_unique<FunctionImporter::ImportFailureInfo>(
VI, Edge.second.getHotness(), Reason, 1);
}
+
if (ForceImportAll) {
std::string Msg = std::string("Failed to import function ") +
VI.name().str() + " due to " +
>From 5edecccb0fb4dc4d6da54b2533484c7c176314c6 Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Tue, 23 Apr 2024 09:16:57 -0700
Subject: [PATCH 4/5] stage changes
---
llvm/lib/Transforms/IPO/FunctionImport.cpp | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index eb0bf36ab26d1f..bc139e5a905bbc 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -996,8 +996,6 @@ static unsigned numGlobalVarSummaries(const ModuleSummaryIndex &Index,
T &Cont) {
unsigned NumGVS = 0;
for (auto &[GUID, Type] : Cont) {
- assert(Type == GlobalValueSummary::Definition &&
- "Declaration type doesn't exist yet");
if (isGlobalVarSummary(Index, GUID))
++NumGVS;
}
@@ -1092,9 +1090,8 @@ void llvm::ComputeCrossModuleImport(
// we convert such variables initializers to "zeroinitializer".
// See processGlobalForThinLTO.
if (!Index.isWriteOnly(GVS))
- for (const auto &VI : GVS->refs()) {
+ for (const auto &VI : GVS->refs())
NewExports.try_emplace(VI, GlobalValueSummary::Declaration);
- }
} else {
auto *FS = cast<FunctionSummary>(S);
for (const auto &Edge : FS->calls())
>From a139e4afc02c1e9f5dfae86f2f4a540cd97d8e87 Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Thu, 2 May 2024 16:15:19 -0700
Subject: [PATCH 5/5] Add test coverage for import delcaration
---
llvm/lib/Transforms/IPO/FunctionImport.cpp | 16 ++-
.../ThinLTO/X86/import_callee_declaration.ll | 111 ++++++++++++++++++
llvm/tools/llvm-link/llvm-link.cpp | 4 +
3 files changed, 125 insertions(+), 6 deletions(-)
create mode 100644 llvm/test/ThinLTO/X86/import_callee_declaration.ll
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index bc139e5a905bbc..b13770ed49d834 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -140,11 +140,12 @@ static cl::opt<bool>
ImportAllIndex("import-all-index",
cl::desc("Import all external functions in index."));
-/// Test-only option.
+/// This is a test-only option.
+/// If this option is enabled, the ThinLTO indexing step will import each
+/// function declaration as a fallback. In a real build this may increase ram
+/// usage of the indexing step unnecessarily.
/// TODO: Implement selective import (based on combined summary analysis) to
/// ensure the imported function has a use case in the postlink pipeline.
-/// Import each function declaration as a fallback in real build may grow map
-/// size unnecessarily in the indexing step.
static cl::opt<bool> ImportDeclaration(
"import-declaration", cl::init(false), cl::Hidden,
cl::desc("If true, import function declaration as fallback if the function "
@@ -1070,8 +1071,6 @@ void llvm::ComputeCrossModuleImport(
const auto &DefinedGVSummaries =
ModuleToDefinedGVSummaries.lookup(ELI.first);
for (auto &[EI, Type] : ELI.second) {
- assert(Type == GlobalValueSummary::Definition &&
- "Declaration type doesn't exist yet");
// Find the copy defined in the exporting module so that we can mark the
// values it references in that specific definition as exported.
// Below we will add all references and called values, without regard to
@@ -1716,8 +1715,13 @@ Expected<bool> FunctionImporter::importFunctions(
continue;
auto GUID = F.getGUID();
auto ImportType = maybeGetImportType(ImportGUIDs, GUID);
- if (!ImportType)
+
+ if (!ImportType) {
+ LLVM_DEBUG(dbgs() << "Not importing function " << GUID << " "
+ << F.getName() << " from "
+ << SrcModule->getSourceFileName() << "\n");
continue;
+ }
const bool ImportDefinition =
*ImportType == GlobalValueSummary::Definition;
LLVM_DEBUG(dbgs() << (ImportDefinition ? "Is" : "Not")
diff --git a/llvm/test/ThinLTO/X86/import_callee_declaration.ll b/llvm/test/ThinLTO/X86/import_callee_declaration.ll
new file mode 100644
index 00000000000000..344bde1a1a07d3
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/import_callee_declaration.ll
@@ -0,0 +1,111 @@
+; RUN: rm -rf %t && split-file %s %t && cd %t
+
+; Generate per-module summaries.
+; RUN: opt -module-summary main.ll -o main.bc
+; RUN: opt -module-summary lib.ll -o lib.bc
+
+; Generate the combined summary using per-module summaries.
+; For function import, set 'import-instr-limit' to 5 and fall back to import
+; function declarations.
+;
+; RUN: llvm-lto2 run \
+; RUN: -import-instr-limit=5 \
+; RUN: -import-declaration \
+; RUN: -thinlto-distributed-indexes \
+; RUN: -thinlto-emit-imports \
+; RUN: -r=main.bc,main,px \
+; RUN: -r=main.bc,small_func, \
+; RUN: -r=main.bc,large_func, \
+; RUN: -r=lib.bc,callee,px \
+; RUN: -r=lib.bc,large_indirect_callee,px \
+; RUN: -r=lib.bc,small_func,px \
+; RUN: -r=lib.bc,large_func,px \
+; RUN: -r=lib.bc,calleeAddrs,px -o summary main.bc lib.bc
+
+; main.ll should import {large_func, large_indirect_callee} as declarations.
+;
+; First disassemble per-module summary and find out the GUID for {large_func, large_indirect_callee}.
+;
+; RUN: llvm-dis lib.bc -o - | FileCheck %s --check-prefix=LIB-DIS
+; LIB-DIS: [[LIBMOD:\^[0-9]+]] = module: (path: "lib.bc", hash: (0, 0, 0, 0, 0))
+; LIB-DIS: [[LARGEFUNC:\^[0-9]+]] = gv: (name: "large_func", summaries: {{.*}}) ; guid = 2418497564662708935
+; LIB-DIS: [[LARGEINDIRECT:\^[0-9]+]] = gv: (name: "large_indirect_callee", summaries: {{.*}}) ; guid = 14343440786664691134
+;
+; Secondly disassemble main's combined summary and verify the import type of
+; these two GUIDs are declaration.
+;
+; RUN: llvm-dis main.bc.thinlto.bc -o - | FileCheck %s --check-prefix=MAIN-DIS
+;
+; MAIN-DIS: [[LIBMOD:\^[0-9]+]] = module: (path: "lib.bc", hash: (0, 0, 0, 0, 0))
+; MAIN-DIS: [[LARGEFUNC:\^[0-9]+]] = gv: (guid: 2418497564662708935, summaries: (function: (module: [[LIBMOD]], flags: ({{.*}} importType: declaration), insts: 6, {{.*}})))
+; MAIN-DIS: [[LARGEINDIRECT:\^[0-9]+]] = gv: (guid: 14343440786664691134, summaries: (function: (module: [[LIBMOD]], flags: ({{.*}} importType: declaration), insts: 7, {{.*}})))
+
+; TODO: Add test coverage for function alias.
+
+;--- main.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @main() {
+ call void @small_func()
+ call void @large_func()
+ ret i32 0
+}
+
+declare void @small_func()
+
+; large_func without attributes
+declare void @large_func()
+
+;--- lib.ll
+source_filename = "lib.cc"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at calleeAddrs = global [2 x ptr] [ptr @large_indirect_callee, ptr @small_indirect_callee]
+
+define void @callee() #1 {
+ ret void
+}
+
+define void @large_indirect_callee()#2 {
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ ret void
+}
+
+define internal void @small_indirect_callee() #0 {
+ ret void
+}
+
+define void @small_func() {
+entry:
+ %0 = load ptr, ptr @calleeAddrs
+ call void %0(), !prof !0
+ %1 = load ptr, ptr getelementptr inbounds ([2 x ptr], ptr @calleeAddrs, i64 0, i64 1)
+ call void %1(), !prof !1
+ ret void
+}
+
+define void @large_func() #0 {
+entry:
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ call void @callee()
+ ret void
+}
+
+attributes #0 = { nounwind norecurse }
+
+attributes #1 = { noinline }
+
+attributes #2 = { norecurse }
+
+!0 = !{!"VP", i32 0, i64 1, i64 14343440786664691134, i64 1}
+!1 = !{!"VP", i32 0, i64 2, i64 13568239288960714650, i64 1}
diff --git a/llvm/tools/llvm-link/llvm-link.cpp b/llvm/tools/llvm-link/llvm-link.cpp
index a6bee02b1302d3..3a201031351525 100644
--- a/llvm/tools/llvm-link/llvm-link.cpp
+++ b/llvm/tools/llvm-link/llvm-link.cpp
@@ -375,6 +375,10 @@ static bool importFunctions(const char *argv0, Module &DestModule) {
if (Verbose)
errs() << "Importing " << FunctionName << " from " << FileName << "\n";
+ // `-import` specifies the `<filename,function-name>` pairs to import as
+ // definition, so make the import type definition directly.
+ // FIXME: A follow-up patch should add test coverage for import declaration
+ // in `llvm-link` CLI (e.g., by introducing a new command line option).
auto &Entry =
ImportList[FileNameStringCache.insert(FileName).first->getKey()];
Entry[F->getGUID()] = GlobalValueSummary::Definition;
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