riccibruno created this revision.
riccibruno added a reviewer: rjmccall.
riccibruno added a project: clang.
Herald added subscribers: cfe-commits, javed.absar.
Only store the NRVO candidate if needed in `ReturnStmt`.
A good chuck of all of the `ReturnStmt` have no NRVO candidate.
For all of them this saves one pointer.
This has no impact on `children()`.
Repository:
rC Clang
https://reviews.llvm.org/D53716
Files:
include/clang/AST/Stmt.h
lib/AST/ASTImporter.cpp
lib/AST/Stmt.cpp
lib/Analysis/BodyFarm.cpp
lib/CodeGen/CGObjC.cpp
lib/Sema/SemaStmt.cpp
lib/Serialization/ASTReaderStmt.cpp
lib/Serialization/ASTWriterStmt.cpp
Index: lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- lib/Serialization/ASTWriterStmt.cpp
+++ lib/Serialization/ASTWriterStmt.cpp
@@ -249,9 +249,15 @@
void ASTStmtWriter::VisitReturnStmt(ReturnStmt *S) {
VisitStmt(S);
+
+ bool HasNRVOCandidate = !!S->getNRVOCandidate();
+ Record.push_back(HasNRVOCandidate);
+
Record.AddStmt(S->getRetValue());
+ if (HasNRVOCandidate)
+ Record.AddDeclRef(S->getNRVOCandidate());
+
Record.AddSourceLocation(S->getReturnLoc());
- Record.AddDeclRef(S->getNRVOCandidate());
Code = serialization::STMT_RETURN;
}
Index: lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- lib/Serialization/ASTReaderStmt.cpp
+++ lib/Serialization/ASTReaderStmt.cpp
@@ -328,9 +328,14 @@
void ASTStmtReader::VisitReturnStmt(ReturnStmt *S) {
VisitStmt(S);
+
+ bool HasNRVOCandidate = Record.readInt();
+
S->setRetValue(Record.readSubExpr());
+ if (HasNRVOCandidate)
+ S->setNRVOCandidate(ReadDeclAs<VarDecl>());
+
S->setReturnLoc(ReadSourceLocation());
- S->setNRVOCandidate(ReadDeclAs<VarDecl>());
}
void ASTStmtReader::VisitDeclStmt(DeclStmt *S) {
@@ -2357,7 +2362,8 @@
break;
case STMT_RETURN:
- S = new (Context) ReturnStmt(Empty);
+ S = ReturnStmt::CreateEmpty(
+ Context, /* HasNRVOCandidate=*/Record[ASTStmtReader::NumStmtFields]);
break;
case STMT_DECL:
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -3220,7 +3220,8 @@
return StmtError();
RetValExp = ER.get();
}
- return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
+ return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
+ /* NRVOCandidate=*/nullptr);
}
if (HasDeducedReturnType) {
@@ -3346,8 +3347,8 @@
return StmtError();
RetValExp = ER.get();
}
- ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
- NRVOCandidate);
+ auto *Result =
+ ReturnStmt::Create(Context, ReturnLoc, RetValExp, NRVOCandidate);
// If we need to check for the named return value optimization,
// or if we need to infer the return type,
@@ -3576,7 +3577,8 @@
return StmtError();
RetValExp = ER.get();
}
- return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
+ return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
+ /* NRVOCandidate=*/nullptr);
}
// FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
@@ -3671,7 +3673,7 @@
}
}
- Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
+ Result = ReturnStmt::Create(Context, ReturnLoc, RetValExp, nullptr);
} else if (!RetValExp && !HasDependentReturnType) {
FunctionDecl *FD = getCurFunctionDecl();
@@ -3693,7 +3695,8 @@
else
Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
- Result = new (Context) ReturnStmt(ReturnLoc);
+ Result = ReturnStmt::Create(Context, ReturnLoc, /* RetExpr=*/nullptr,
+ /* NRVOCandidate=*/nullptr);
} else {
assert(RetValExp || HasDependentReturnType);
const VarDecl *NRVOCandidate = nullptr;
@@ -3746,7 +3749,7 @@
return StmtError();
RetValExp = ER.get();
}
- Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
+ Result = ReturnStmt::Create(Context, ReturnLoc, RetValExp, NRVOCandidate);
}
// If we need to check for the named return value optimization, save the
Index: lib/CodeGen/CGObjC.cpp
===================================================================
--- lib/CodeGen/CGObjC.cpp
+++ lib/CodeGen/CGObjC.cpp
@@ -883,9 +883,10 @@
// If there's a non-trivial 'get' expression, we just have to emit that.
if (!hasTrivialGetExpr(propImpl)) {
if (!AtomicHelperFn) {
- ReturnStmt ret(SourceLocation(), propImpl->getGetterCXXConstructor(),
- /*nrvo*/ nullptr);
- EmitReturnStmt(ret);
+ auto *ret = ReturnStmt::Create(getContext(), SourceLocation(),
+ propImpl->getGetterCXXConstructor(),
+ /* NRVOCandidate=*/nullptr);
+ EmitReturnStmt(*ret);
}
else {
ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
Index: lib/Analysis/BodyFarm.cpp
===================================================================
--- lib/Analysis/BodyFarm.cpp
+++ lib/Analysis/BodyFarm.cpp
@@ -201,10 +201,9 @@
/*arrow=*/true, /*free=*/false);
}
-
ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) {
- return new (C) ReturnStmt(SourceLocation(), const_cast<Expr*>(RetVal),
- nullptr);
+ return ReturnStmt::Create(C, SourceLocation(), const_cast<Expr *>(RetVal),
+ /* NRVOCandidate=*/nullptr);
}
IntegerLiteral *ASTMaker::makeIntegerLiteral(uint64_t Value, QualType Ty) {
Index: lib/AST/Stmt.cpp
===================================================================
--- lib/AST/Stmt.cpp
+++ lib/AST/Stmt.cpp
@@ -1042,11 +1042,33 @@
}
// ReturnStmt
-const Expr* ReturnStmt::getRetValue() const {
- return cast_or_null<Expr>(RetExpr);
+ReturnStmt::ReturnStmt(SourceLocation RL, Expr *E, const VarDecl *NRVOCandidate)
+ : Stmt(ReturnStmtClass), RetExpr(E) {
+ bool HasNRVOCandidate = !!NRVOCandidate;
+ ReturnStmtBits.HasNRVOCandidate = HasNRVOCandidate;
+ if (HasNRVOCandidate)
+ setNRVOCandidate(NRVOCandidate);
+ setReturnLoc(RL);
}
-Expr* ReturnStmt::getRetValue() {
- return cast_or_null<Expr>(RetExpr);
+
+ReturnStmt::ReturnStmt(EmptyShell Empty, bool HasNRVOCandidate)
+ : Stmt(ReturnStmtClass, Empty) {
+ ReturnStmtBits.HasNRVOCandidate = HasNRVOCandidate;
+}
+
+ReturnStmt *ReturnStmt::Create(const ASTContext &Ctx, SourceLocation RL,
+ Expr *E, const VarDecl *NRVOCandidate) {
+ bool HasNRVOCandidate = !!NRVOCandidate;
+ void *Mem = Ctx.Allocate(totalSizeToAlloc<const VarDecl *>(HasNRVOCandidate),
+ alignof(ReturnStmt));
+ return new (Mem) ReturnStmt(RL, E, NRVOCandidate);
+}
+
+ReturnStmt *ReturnStmt::CreateEmpty(const ASTContext &Ctx,
+ bool HasNRVOCandidate) {
+ void *Mem = Ctx.Allocate(totalSizeToAlloc<const VarDecl *>(HasNRVOCandidate),
+ alignof(ReturnStmt));
+ return new (Mem) ReturnStmt(EmptyShell(), HasNRVOCandidate);
}
// CaseStmt
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -5917,8 +5917,8 @@
const VarDecl *ToNRVOCandidate;
std::tie(ToReturnLoc, ToRetValue, ToNRVOCandidate) = *Imp;
- return new (Importer.getToContext()) ReturnStmt(
- ToReturnLoc, ToRetValue, ToNRVOCandidate);
+ return ReturnStmt::Create(Importer.getToContext(), ToReturnLoc, ToRetValue,
+ ToNRVOCandidate);
}
ExpectedStmt ASTNodeImporter::VisitCXXCatchStmt(CXXCatchStmt *S) {
Index: include/clang/AST/Stmt.h
===================================================================
--- include/clang/AST/Stmt.h
+++ include/clang/AST/Stmt.h
@@ -256,6 +256,9 @@
unsigned : NumStmtBits;
+ /// True if this ReturnStmt has storage for an NRVO candidate.
+ unsigned HasNRVOCandidate : 1;
+
/// The location of the "return".
SourceLocation RetLoc;
};
@@ -1987,40 +1990,67 @@
/// return a value, and it allows returning a value in functions declared to
/// return void. We explicitly model this in the AST, which means you can't
/// depend on the return type of the function and the presence of an argument.
-class ReturnStmt : public Stmt {
+class ReturnStmt final
+ : public Stmt,
+ private llvm::TrailingObjects<ReturnStmt, const VarDecl *> {
+ friend TrailingObjects;
+
+ /// The return expression.
Stmt *RetExpr;
- const VarDecl *NRVOCandidate;
-public:
- explicit ReturnStmt(SourceLocation RL) : ReturnStmt(RL, nullptr, nullptr) {}
+ // ReturnStmt is followed optionally by a trailing "const VarDecl *"
+ // for the NRVO candidate. Present if and only if hasNRVOCandidate().
- ReturnStmt(SourceLocation RL, Expr *E, const VarDecl *NRVOCandidate)
- : Stmt(ReturnStmtClass), RetExpr((Stmt *)E),
- NRVOCandidate(NRVOCandidate) {
- ReturnStmtBits.RetLoc = RL;
+ /// True if this ReturnStmt has storage for an NRVO candidate.
+ bool hasNRVOCandidate() const { return ReturnStmtBits.HasNRVOCandidate; }
+
+ unsigned numTrailingObjects(OverloadToken<const VarDecl *>) const {
+ return hasNRVOCandidate();
}
- /// Build an empty return expression.
- explicit ReturnStmt(EmptyShell Empty) : Stmt(ReturnStmtClass, Empty) {}
+ /// Build a return statement.
+ ReturnStmt(SourceLocation RL, Expr *E, const VarDecl *NRVOCandidate);
- const Expr *getRetValue() const;
- Expr *getRetValue();
- void setRetValue(Expr *E) { RetExpr = reinterpret_cast<Stmt*>(E); }
+ /// Build an empty return statement.
+ explicit ReturnStmt(EmptyShell Empty, bool HasNRVOCandidate);
- SourceLocation getReturnLoc() const { return ReturnStmtBits.RetLoc; }
- void setReturnLoc(SourceLocation L) { ReturnStmtBits.RetLoc = L; }
+public:
+ /// Create a return statement.
+ static ReturnStmt *Create(const ASTContext &Ctx, SourceLocation RL, Expr *E,
+ const VarDecl *NRVOCandidate);
+
+ /// Create an empty return statement, optionally with
+ /// storage for an NRVO candidate.
+ static ReturnStmt *CreateEmpty(const ASTContext &Ctx, bool HasNRVOCandidate);
+
+ Expr *getRetValue() { return reinterpret_cast<Expr *>(RetExpr); }
+ const Expr *getRetValue() const { return reinterpret_cast<Expr *>(RetExpr); }
+ void setRetValue(Expr *E) { RetExpr = reinterpret_cast<Stmt *>(E); }
/// Retrieve the variable that might be used for the named return
/// value optimization.
///
/// The optimization itself can only be performed if the variable is
/// also marked as an NRVO object.
- const VarDecl *getNRVOCandidate() const { return NRVOCandidate; }
- void setNRVOCandidate(const VarDecl *Var) { NRVOCandidate = Var; }
+ const VarDecl *getNRVOCandidate() const {
+ return hasNRVOCandidate() ? *getTrailingObjects<const VarDecl *>()
+ : nullptr;
+ }
- SourceLocation getBeginLoc() const { return getReturnLoc(); }
+ /// Set the variable that might be used for the named return value
+ /// optimization. The return statement must have storage for it,
+ /// which is the case if and only if hasNRVOCandidate() is true.
+ void setNRVOCandidate(const VarDecl *Var) {
+ assert(hasNRVOCandidate() &&
+ "This return statement has no storage for an NRVO candidate!");
+ *getTrailingObjects<const VarDecl *>() = Var;
+ }
- SourceLocation getEndLoc() const {
+ SourceLocation getReturnLoc() const { return ReturnStmtBits.RetLoc; }
+ void setReturnLoc(SourceLocation L) { ReturnStmtBits.RetLoc = L; }
+
+ SourceLocation getBeginLoc() const { return getReturnLoc(); }
+ SourceLocation getEndLoc() const LLVM_READONLY {
return RetExpr ? RetExpr->getEndLoc() : getReturnLoc();
}
@@ -2030,7 +2060,8 @@
// Iterators
child_range children() {
- if (RetExpr) return child_range(&RetExpr, &RetExpr+1);
+ if (RetExpr)
+ return child_range(&RetExpr, &RetExpr + 1);
return child_range(child_iterator(), child_iterator());
}
};
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