Reuse VarDecl::Init to store the default argument of a ParmVarDecl,
reducing the size of ParmVarDecl by one pointer. Also means that we'll
properly (de-)serialize default arguments in C++ PCH files.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76487 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 55f141c..ed1a231 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -237,8 +237,17 @@
/// It is illegal to call this function with SC == None.
static const char *getStorageClassSpecifierString(StorageClass SC);
+protected:
+ /// \brief Placeholder type used in Init to denote an unparsed C++ default
+ /// argument.
+ struct UnparsedDefaultArgument;
+
+ /// \brief The initializer for this variable or, for a ParmVarDecl, the
+ /// C++ default argument.
+ mutable llvm::PointerUnion3<Stmt *, EvaluatedStmt *, UnparsedDefaultArgument*>
+ Init;
+
private:
- mutable llvm::PointerUnion<Stmt *, EvaluatedStmt *> Init;
// FIXME: This can be packed into the bitfields in Decl.
unsigned SClass : 3;
bool ThreadSpecified : 1;
@@ -295,9 +304,10 @@
return 0;
const Stmt *S = Init.dyn_cast<Stmt *>();
- if (!S)
- S = Init.get<EvaluatedStmt *>()->Value;
-
+ if (!S) {
+ if (EvaluatedStmt *ES = Init.dyn_cast<EvaluatedStmt*>())
+ S = ES->Value;
+ }
return (const Expr*) S;
}
Expr *getInit() {
@@ -305,17 +315,19 @@
return 0;
Stmt *S = Init.dyn_cast<Stmt *>();
- if (!S)
- S = Init.get<EvaluatedStmt *>()->Value;
+ if (!S) {
+ if (EvaluatedStmt *ES = Init.dyn_cast<EvaluatedStmt*>())
+ S = ES->Value;
+ }
return (Expr*) S;
}
/// \brief Retrieve the address of the initializer expression.
Stmt **getInitAddress() {
- if (Init.is<Stmt *>())
- return reinterpret_cast<Stmt **>(&Init); // FIXME: ugly hack
- return &Init.get<EvaluatedStmt *>()->Value;
+ if (EvaluatedStmt *ES = Init.dyn_cast<EvaluatedStmt*>())
+ return &ES->Value;
+ return reinterpret_cast<Stmt **>(&Init); // FIXME: ugly hack
}
void setInit(ASTContext &C, Expr *I);
@@ -495,12 +507,12 @@
class ImplicitParamDecl : public VarDecl {
protected:
ImplicitParamDecl(Kind DK, DeclContext *DC, SourceLocation L,
- IdentifierInfo *Id, QualType Tw)
+ IdentifierInfo *Id, QualType Tw)
: VarDecl(DK, DC, L, Id, Tw, VarDecl::None) {}
public:
static ImplicitParamDecl *Create(ASTContext &C, DeclContext *DC,
- SourceLocation L, IdentifierInfo *Id,
- QualType T);
+ SourceLocation L, IdentifierInfo *Id,
+ QualType T);
// Implement isa/cast/dyncast/etc.
static bool classof(const ImplicitParamDecl *D) { return true; }
static bool classof(const Decl *D) { return D->getKind() == ImplicitParam; }
@@ -513,14 +525,21 @@
/// in, inout, etc.
unsigned objcDeclQualifier : 6;
- /// Default argument, if any. [C++ Only]
- Expr *DefaultArg;
+ /// \brief Retrieves the fake "value" of an unparsed
+ static Expr *getUnparsedDefaultArgValue() {
+ uintptr_t Value = (uintptr_t)-1;
+ // Mask off the low bits
+ Value &= ~(uintptr_t)0x07;
+ return reinterpret_cast<Expr*> (Value);
+ }
+
protected:
ParmVarDecl(Kind DK, DeclContext *DC, SourceLocation L,
IdentifierInfo *Id, QualType T, StorageClass S,
Expr *DefArg)
- : VarDecl(DK, DC, L, Id, T, S),
- objcDeclQualifier(OBJC_TQ_None), DefaultArg(DefArg) {}
+ : VarDecl(DK, DC, L, Id, T, S), objcDeclQualifier(OBJC_TQ_None) {
+ setDefaultArg(DefArg);
+ }
public:
static ParmVarDecl *Create(ASTContext &C, DeclContext *DC,
@@ -536,18 +555,20 @@
const Expr *getDefaultArg() const {
assert(!hasUnparsedDefaultArg() && "Default argument is not yet parsed!");
- return DefaultArg;
+ return getInit();
}
Expr *getDefaultArg() {
assert(!hasUnparsedDefaultArg() && "Default argument is not yet parsed!");
- return DefaultArg;
+ return getInit();
}
- void setDefaultArg(Expr *defarg) { DefaultArg = defarg; }
+ void setDefaultArg(Expr *defarg) {
+ Init = reinterpret_cast<Stmt *>(defarg);
+ }
/// hasDefaultArg - Determines whether this parameter has a default argument,
/// either parsed or not.
bool hasDefaultArg() const {
- return DefaultArg != 0;
+ return getInit() || hasUnparsedDefaultArg();
}
/// hasUnparsedDefaultArg - Determines whether this parameter has a
@@ -561,7 +582,7 @@
/// }; // x has a regular default argument now
/// @endcode
bool hasUnparsedDefaultArg() const {
- return DefaultArg == reinterpret_cast<Expr *>(-1);
+ return Init.is<UnparsedDefaultArgument*>();
}
/// setUnparsedDefaultArg - Specify that this parameter has an
@@ -569,7 +590,9 @@
/// real default argument via setDefaultArg when the class
/// definition enclosing the function declaration that owns this
/// default argument is completed.
- void setUnparsedDefaultArg() { DefaultArg = reinterpret_cast<Expr *>(-1); }
+ void setUnparsedDefaultArg() {
+ Init = (UnparsedDefaultArgument *)0;
+ }
QualType getOriginalType() const;
diff --git a/lib/Frontend/PCHReaderDecl.cpp b/lib/Frontend/PCHReaderDecl.cpp
index 8df245a..f2b7bdd 100644
--- a/lib/Frontend/PCHReaderDecl.cpp
+++ b/lib/Frontend/PCHReaderDecl.cpp
@@ -358,7 +358,6 @@
void PCHDeclReader::VisitParmVarDecl(ParmVarDecl *PD) {
VisitVarDecl(PD);
PD->setObjCDeclQualifier((Decl::ObjCDeclQualifier)Record[Idx++]);
- // FIXME: default argument (C++ only)
}
void PCHDeclReader::VisitOriginalParmVarDecl(OriginalParmVarDecl *PD) {
diff --git a/lib/Frontend/PCHWriterDecl.cpp b/lib/Frontend/PCHWriterDecl.cpp
index ff5c576..b2c6fd2 100644
--- a/lib/Frontend/PCHWriterDecl.cpp
+++ b/lib/Frontend/PCHWriterDecl.cpp
@@ -354,9 +354,6 @@
void PCHDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
VisitVarDecl(D);
Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
- // FIXME: emit default argument (C++)
- // FIXME: why isn't the "default argument" just stored as the initializer
- // in VarDecl?
Code = pch::DECL_PARM_VAR;