https://github.com/jansvoboda11 created
https://github.com/llvm/llvm-project/pull/112795
In `clang-scan-deps`, we're creating lots of `Module` instances. Allocating
them all in a bump-pointer allocator reduces the number of retired instructions
by 1-1.5% on my workload.
>From 7e00bbe74f71c55dfd3e3a75d4459187a90f6426 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svob...@apple.com>
Date: Thu, 17 Oct 2024 15:26:18 -0700
Subject: [PATCH] [clang] Allocate `Module` instances in `BumpPtrAllocator`
---
clang/include/clang/Basic/Module.h | 16 +++++--
clang/include/clang/Lex/ModuleMap.h | 9 +++-
clang/lib/Basic/Module.cpp | 26 ++---------
clang/lib/Lex/ModuleMap.cpp | 72 +++++++++++++++++------------
clang/lib/Lex/Pragma.cpp | 3 +-
5 files changed, 68 insertions(+), 58 deletions(-)
diff --git a/clang/include/clang/Basic/Module.h
b/clang/include/clang/Basic/Module.h
index e86f4303d732b8..9c5d33fbb562cc 100644
--- a/clang/include/clang/Basic/Module.h
+++ b/clang/include/clang/Basic/Module.h
@@ -48,6 +48,7 @@ namespace clang {
class FileManager;
class LangOptions;
+class ModuleMap;
class TargetInfo;
/// Describes the name of a module.
@@ -99,6 +100,15 @@ struct ASTFileSignature : std::array<uint8_t, 20> {
}
};
+/// Required to construct a Module.
+///
+/// This tag type is only constructible by ModuleMap, guaranteeing it ownership
+/// of all Module instances.
+class ModuleConstructorTag {
+ explicit ModuleConstructorTag() = default;
+ friend ModuleMap;
+};
+
/// Describes a module or submodule.
///
/// Aligned to 8 bytes to allow for llvm::PointerIntPair<Module *, 3>.
@@ -497,8 +507,9 @@ class alignas(8) Module {
std::vector<Conflict> Conflicts;
/// Construct a new module or submodule.
- Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent,
- bool IsFramework, bool IsExplicit, unsigned VisibilityID);
+ Module(ModuleConstructorTag, StringRef Name, SourceLocation DefinitionLoc,
+ Module *Parent, bool IsFramework, bool IsExplicit,
+ unsigned VisibilityID);
~Module();
@@ -749,7 +760,6 @@ class alignas(8) Module {
///
/// \returns The submodule if found, or NULL otherwise.
Module *findSubmodule(StringRef Name) const;
- Module *findOrInferSubmodule(StringRef Name);
/// Get the Global Module Fragment (sub-module) for this module, it there is
/// one.
diff --git a/clang/include/clang/Lex/ModuleMap.h
b/clang/include/clang/Lex/ModuleMap.h
index 2e28ff6823cb2a..75b567a347cb6c 100644
--- a/clang/include/clang/Lex/ModuleMap.h
+++ b/clang/include/clang/Lex/ModuleMap.h
@@ -93,9 +93,12 @@ class ModuleMap {
/// named LangOpts::CurrentModule, if we've loaded it).
Module *SourceModule = nullptr;
+ /// The allocator for all (sub)modules.
+ llvm::SpecificBumpPtrAllocator<Module> ModulesAlloc;
+
/// Submodules of the current module that have not yet been attached to it.
- /// (Ownership is transferred if/when we create an enclosing module.)
- llvm::SmallVector<std::unique_ptr<Module>, 8> PendingSubmodules;
+ /// (Relationship is set up if/when we create an enclosing module.)
+ llvm::SmallVector<Module *, 8> PendingSubmodules;
/// The top-level modules that are known.
llvm::StringMap<Module *> Modules;
@@ -502,6 +505,8 @@ class ModuleMap {
/// \returns The named module, if known; otherwise, returns null.
Module *findModule(StringRef Name) const;
+ Module *findOrInferSubmodule(Module *Parent, StringRef Name);
+
/// Retrieve a module with the given name using lexical name lookup,
/// starting at the given context.
///
diff --git a/clang/lib/Basic/Module.cpp b/clang/lib/Basic/Module.cpp
index fee372bce3a367..ad52fccff5dc7f 100644
--- a/clang/lib/Basic/Module.cpp
+++ b/clang/lib/Basic/Module.cpp
@@ -34,8 +34,9 @@
using namespace clang;
-Module::Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent,
- bool IsFramework, bool IsExplicit, unsigned VisibilityID)
+Module::Module(ModuleConstructorTag, StringRef Name,
+ SourceLocation DefinitionLoc, Module *Parent, bool IsFramework,
+ bool IsExplicit, unsigned VisibilityID)
: Name(Name), DefinitionLoc(DefinitionLoc), Parent(Parent),
VisibilityID(VisibilityID), IsUnimportable(false),
HasIncompatibleModuleFile(false), IsAvailable(true),
@@ -58,11 +59,7 @@ Module::Module(StringRef Name, SourceLocation DefinitionLoc,
Module *Parent,
}
}
-Module::~Module() {
- for (auto *Submodule : SubModules) {
- delete Submodule;
- }
-}
+Module::~Module() = default;
static bool isPlatformEnvironment(const TargetInfo &Target, StringRef Feature)
{
StringRef Platform = Target.getPlatformName();
@@ -361,21 +358,6 @@ Module *Module::findSubmodule(StringRef Name) const {
return SubModules[Pos->getValue()];
}
-Module *Module::findOrInferSubmodule(StringRef Name) {
- llvm::StringMap<unsigned>::const_iterator Pos = SubModuleIndex.find(Name);
- if (Pos != SubModuleIndex.end())
- return SubModules[Pos->getValue()];
- if (!InferSubmodules)
- return nullptr;
- Module *Result = new Module(Name, SourceLocation(), this, false,
InferExplicitSubmodules, 0);
- Result->InferExplicitSubmodules = InferExplicitSubmodules;
- Result->InferSubmodules = InferSubmodules;
- Result->InferExportWildcard = InferExportWildcard;
- if (Result->InferExportWildcard)
- Result->Exports.push_back(Module::ExportDecl(nullptr, true));
- return Result;
-}
-
Module *Module::getGlobalModuleFragment() const {
assert(isNamedModuleUnit() && "We should only query the global module "
"fragment from the C++20 Named modules");
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 2aada51c71c503..fd6bc17ae9cdac 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -362,12 +362,7 @@ ModuleMap::ModuleMap(SourceManager &SourceMgr,
DiagnosticsEngine &Diags,
MMapLangOpts.LineComment = true;
}
-ModuleMap::~ModuleMap() {
- for (auto &M : Modules)
- delete M.getValue();
- for (auto *M : ShadowModules)
- delete M;
-}
+ModuleMap::~ModuleMap() = default;
void ModuleMap::setTarget(const TargetInfo &Target) {
assert((!this->Target || this->Target == &Target) &&
@@ -831,6 +826,22 @@ Module *ModuleMap::findModule(StringRef Name) const {
return nullptr;
}
+Module *ModuleMap::findOrInferSubmodule(Module *Parent, StringRef Name) {
+ if (Module *SubM = Parent->findSubmodule(Name))
+ return SubM;
+ if (!Parent->InferSubmodules)
+ return nullptr;
+ Module *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, Name, SourceLocation(), Parent, false,
+ Parent->InferExplicitSubmodules, 0);
+ Result->InferExplicitSubmodules = Parent->InferExplicitSubmodules;
+ Result->InferSubmodules = Parent->InferSubmodules;
+ Result->InferExportWildcard = Parent->InferExportWildcard;
+ if (Result->InferExportWildcard)
+ Result->Exports.push_back(Module::ExportDecl(nullptr, true));
+ return Result;
+}
+
Module *ModuleMap::lookupModuleUnqualified(StringRef Name,
Module *Context) const {
for(; Context; Context = Context->Parent) {
@@ -857,8 +868,9 @@ std::pair<Module *, bool>
ModuleMap::findOrCreateModule(StringRef Name,
return std::make_pair(Sub, false);
// Create a new module with this name.
- Module *Result = new Module(Name, SourceLocation(), Parent, IsFramework,
- IsExplicit, NumCreatedModules++);
+ Module *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, Name, SourceLocation(), Parent,
+ IsFramework, IsExplicit, NumCreatedModules++);
if (!Parent) {
if (LangOpts.CurrentModule == Name)
SourceModule = Result;
@@ -870,8 +882,9 @@ std::pair<Module *, bool>
ModuleMap::findOrCreateModule(StringRef Name,
Module *ModuleMap::createGlobalModuleFragmentForModuleUnit(SourceLocation Loc,
Module *Parent) {
- auto *Result = new Module("<global>", Loc, Parent, /*IsFramework*/ false,
- /*IsExplicit*/ true, NumCreatedModules++);
+ auto *Result = new (ModulesAlloc.Allocate()) Module(
+ ModuleConstructorTag{}, "<global>", Loc, Parent, /*IsFramework=*/false,
+ /*IsExplicit=*/true, NumCreatedModules++);
Result->Kind = Module::ExplicitGlobalModuleFragment;
// If the created module isn't owned by a parent, send it to
PendingSubmodules
// to wait for its parent.
@@ -888,9 +901,9 @@
ModuleMap::createImplicitGlobalModuleFragmentForModuleUnit(SourceLocation Loc,
// Note: Here the `IsExplicit` parameter refers to the semantics in clang
// modules. All the non-explicit submodules in clang modules will be exported
// too. Here we simplify the implementation by using the concept.
- auto *Result =
- new Module("<implicit global>", Loc, Parent, /*IsFramework=*/false,
- /*IsExplicit=*/false, NumCreatedModules++);
+ auto *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, "<implicit global>", Loc, Parent,
+ /*IsFramework=*/false, /*IsExplicit=*/false, NumCreatedModules++);
Result->Kind = Module::ImplicitGlobalModuleFragment;
return Result;
}
@@ -898,25 +911,23 @@
ModuleMap::createImplicitGlobalModuleFragmentForModuleUnit(SourceLocation Loc,
Module *
ModuleMap::createPrivateModuleFragmentForInterfaceUnit(Module *Parent,
SourceLocation Loc) {
- auto *Result =
- new Module("<private>", Loc, Parent, /*IsFramework*/ false,
- /*IsExplicit*/ true, NumCreatedModules++);
+ auto *Result = new (ModulesAlloc.Allocate()) Module(
+ ModuleConstructorTag{}, "<private>", Loc, Parent, /*IsFramework=*/false,
+ /*IsExplicit=*/true, NumCreatedModules++);
Result->Kind = Module::PrivateModuleFragment;
return Result;
}
Module *ModuleMap::createModuleUnitWithKind(SourceLocation Loc, StringRef Name,
Module::ModuleKind Kind) {
- auto *Result =
- new Module(Name, Loc, nullptr, /*IsFramework*/ false,
- /*IsExplicit*/ false, NumCreatedModules++);
+ auto *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, Name, Loc, nullptr, /*IsFramework=*/false,
+ /*IsExplicit=*/false, NumCreatedModules++);
Result->Kind = Kind;
// Reparent any current global module fragment as a submodule of this module.
- for (auto &Submodule : PendingSubmodules) {
+ for (auto &Submodule : PendingSubmodules)
Submodule->setParent(Result);
- Submodule.release(); // now owned by parent
- }
PendingSubmodules.clear();
return Result;
}
@@ -968,8 +979,9 @@ Module *ModuleMap::createHeaderUnit(SourceLocation Loc,
StringRef Name,
assert(LangOpts.CurrentModule == Name && "module name mismatch");
assert(!Modules[Name] && "redefining existing module");
- auto *Result = new Module(Name, Loc, nullptr, /*IsFramework*/ false,
- /*IsExplicit*/ false, NumCreatedModules++);
+ auto *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, Name, Loc, nullptr, /*IsFramework=*/false,
+ /*IsExplicit=*/false, NumCreatedModules++);
Result->Kind = Module::ModuleHeaderUnit;
Modules[Name] = SourceModule = Result;
addHeader(Result, H, NormalHeader);
@@ -1082,9 +1094,9 @@ Module *ModuleMap::inferFrameworkModule(DirectoryEntryRef
FrameworkDir,
if (!UmbrellaHeader)
return nullptr;
- Module *Result = new Module(ModuleName, SourceLocation(), Parent,
- /*IsFramework=*/true, /*IsExplicit=*/false,
- NumCreatedModules++);
+ Module *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, ModuleName, SourceLocation(), Parent,
+ /*IsFramework=*/true, /*IsExplicit=*/false, NumCreatedModules++);
InferredModuleAllowedBy[Result] = ModuleMapFID;
Result->IsInferred = true;
if (!Parent) {
@@ -1173,9 +1185,9 @@ Module *ModuleMap::createShadowedModule(StringRef Name,
bool IsFramework,
Module *ShadowingModule) {
// Create a new module with this name.
- Module *Result =
- new Module(Name, SourceLocation(), /*Parent=*/nullptr, IsFramework,
- /*IsExplicit=*/false, NumCreatedModules++);
+ Module *Result = new (ModulesAlloc.Allocate())
+ Module(ModuleConstructorTag{}, Name, SourceLocation(),
/*Parent=*/nullptr,
+ IsFramework, /*IsExplicit=*/false, NumCreatedModules++);
Result->ShadowingModule = ShadowingModule;
Result->markUnavailable(/*Unimportable*/true);
ModuleScopeIDs[Result] = CurrentModuleScopeID;
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 10f0ab7180e62d..6ec63b91df4bec 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -1752,6 +1752,7 @@ struct PragmaModuleBeginHandler : public PragmaHandler {
// Find the module we're entering. We require that a module map for it
// be loaded or implicitly loadable.
auto &HSI = PP.getHeaderSearchInfo();
+ auto &MM = HSI.getModuleMap();
Module *M = HSI.lookupModule(Current, ModuleName.front().second);
if (!M) {
PP.Diag(ModuleName.front().second,
@@ -1759,7 +1760,7 @@ struct PragmaModuleBeginHandler : public PragmaHandler {
return;
}
for (unsigned I = 1; I != ModuleName.size(); ++I) {
- auto *NewM = M->findOrInferSubmodule(ModuleName[I].first->getName());
+ auto *NewM = MM.findOrInferSubmodule(M, ModuleName[I].first->getName());
if (!NewM) {
PP.Diag(ModuleName[I].second, diag::err_pp_module_begin_no_submodule)
<< M->getFullModuleName() << ModuleName[I].first;
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