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-rw-r--r--include/clang/AST/Decl.h57
-rw-r--r--include/clang/Parse/Scope.h2
-rw-r--r--lib/AST/Decl.cpp77
-rw-r--r--lib/Sema/Sema.h3
-rw-r--r--lib/Sema/SemaDecl.cpp34
-rw-r--r--test/Sema/redefinition.c5
6 files changed, 162 insertions, 16 deletions
diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 0a037998a3..ffa0d4bc9f 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -288,8 +288,17 @@ protected:
friend Decl* Decl::Create(llvm::Deserializer& D, ASTContext& C);
};
-/// FunctionDecl - An instance of this class is created to represent a function
-/// declaration or definition.
+/// FunctionDecl - An instance of this class is created to represent a
+/// function declaration or definition.
+///
+/// Since a given function can be declared several times in a program,
+/// there may be several FunctionDecls that correspond to that
+/// function. Only one of those FunctionDecls will be found when
+/// traversing the list of declarations in the context of the
+/// FunctionDecl (e.g., the translation unit); this FunctionDecl
+/// contains all of the information known about the function. Other,
+/// previous declarations of the function are available via the
+/// getPreviousDeclaration() chain.
class FunctionDecl : public ValueDecl, public DeclContext {
public:
enum StorageClass {
@@ -313,13 +322,25 @@ private:
bool IsInline : 1;
bool IsImplicit : 1;
+ /// PreviousDeclaration - A link to the previous declaration of this
+ /// same function, NULL if this is the first declaration. For
+ /// example, in the following code, the PreviousDeclaration can be
+ /// traversed several times to see all three declarations of the
+ /// function "f", the last of which is also a definition.
+ ///
+ /// int f(int x, int y = 1);
+ /// int f(int x = 0, int y);
+ /// int f(int x, int y) { return x + y; }
+ FunctionDecl *PreviousDeclaration;
+
FunctionDecl(DeclContext *CD, SourceLocation L,
IdentifierInfo *Id, QualType T,
StorageClass S, bool isInline, ScopedDecl *PrevDecl)
: ValueDecl(Function, CD, L, Id, T, PrevDecl),
DeclContext(Function),
ParamInfo(0), Body(0), DeclChain(0), SClass(S),
- IsInline(isInline), IsImplicit(0) {}
+ IsInline(isInline), IsImplicit(0), PreviousDeclaration(0) {}
+
virtual ~FunctionDecl();
public:
static FunctionDecl *Create(ASTContext &C, DeclContext *CD, SourceLocation L,
@@ -327,7 +348,23 @@ public:
StorageClass S = None, bool isInline = false,
ScopedDecl *PrevDecl = 0);
- Stmt *getBody() const { return Body; }
+ /// getBody - Retrieve the body (definition) of the function. The
+ /// function body might be in any of the (re-)declarations of this
+ /// function. The variant that accepts a FunctionDecl pointer will
+ /// set that function declaration to the actual declaration
+ /// containing the body (if there is one).
+ Stmt *getBody(const FunctionDecl *&Definition) const;
+ Stmt *getBody() const {
+ const FunctionDecl* Definition;
+ return getBody(Definition);
+ }
+
+ /// isThisDeclarationADefinition - Returns whether this specific
+ /// declaration of the function is also a definition. This does not
+ /// determine whether the function has been defined (e.g., in a
+ /// previous definition); for that information, use getBody.
+ bool isThisDeclarationADefinition() const { return Body != 0; }
+
void setBody(Stmt *B) { Body = B; }
bool isImplicit() { return IsImplicit; }
@@ -336,6 +373,12 @@ public:
ScopedDecl *getDeclChain() const { return DeclChain; }
void setDeclChain(ScopedDecl *D) { DeclChain = D; }
+ /// getPreviousDeclaration - Return the previous declaration of this
+ /// function.
+ const FunctionDecl *getPreviousDeclaration() const {
+ return PreviousDeclaration;
+ }
+
// Iterator access to formal parameters.
unsigned param_size() const { return getNumParams(); }
typedef ParmVarDecl **param_iterator;
@@ -367,7 +410,11 @@ public:
}
StorageClass getStorageClass() const { return StorageClass(SClass); }
bool isInline() const { return IsInline; }
-
+
+ /// AddRedeclaration - Adds the function declaration FD as a
+ /// redeclaration of this function.
+ void AddRedeclaration(FunctionDecl *FD);
+
// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return D->getKind() == Function; }
static bool classof(const FunctionDecl *D) { return true; }
diff --git a/include/clang/Parse/Scope.h b/include/clang/Parse/Scope.h
index 92d4cd44dc..5db9b2dd76 100644
--- a/include/clang/Parse/Scope.h
+++ b/include/clang/Parse/Scope.h
@@ -113,7 +113,7 @@ public:
void AddDecl(Action::DeclTy *D) {
DeclsInScope.insert(D);
}
-
+
/// isDeclScope - Return true if this is the scope that the specified decl is
/// declared in.
bool isDeclScope(Action::DeclTy *D) {
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 6ebaac569f..11e6bcfb0f 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -403,6 +403,18 @@ const char *NamedDecl::getName() const {
FunctionDecl::~FunctionDecl() {
delete[] ParamInfo;
delete Body;
+ delete PreviousDeclaration;
+}
+
+Stmt *FunctionDecl::getBody(const FunctionDecl *&Definition) const {
+ for (const FunctionDecl *FD = this; FD != 0; FD = FD->PreviousDeclaration) {
+ if (FD->Body) {
+ Definition = FD;
+ return FD->Body;
+ }
+ }
+
+ return 0;
}
unsigned FunctionDecl::getNumParams() const {
@@ -436,6 +448,71 @@ unsigned FunctionDecl::getMinRequiredArguments() const {
return NumRequiredArgs;
}
+/// AddRedeclaration - Specifies that this function declaration has been
+/// redeclared by the function declaration FD. FD must be a
+/// redeclaration of this based on the semantics of the language being
+/// translated ("compatible" function types in C, same signatures in
+/// C++).
+void FunctionDecl::AddRedeclaration(FunctionDecl *FD) {
+ assert(FD->PreviousDeclaration == 0 &&
+ "Redeclaration already has a previous declaration!");
+
+ // Insert FD into the list of previous declarations of this
+ // function.
+ FD->PreviousDeclaration = this->PreviousDeclaration;
+ this->PreviousDeclaration = FD;
+
+ // Swap the contents of this function declaration and FD. This
+ // effectively transforms the original declaration into the most
+ // recent declaration, so that all references to this declaration
+ // remain valid (and have information from *all* declarations),
+ // while retaining all of the information about previous
+ // declarations as well.
+
+ // Swap parameters, so that the most recent parameter names and
+ // exact types (e.g., enum vs int) show up in the original
+ // declaration.
+ ParmVarDecl **thisParamInfo = this->ParamInfo;
+ this->ParamInfo = FD->ParamInfo;
+ FD->ParamInfo = thisParamInfo;
+
+ // Swap the function body: all declarations share the same function
+ // body, but we keep track of who actually defined that function
+ // body by keeping the pointer to the body stored in that node.
+ Stmt *thisBody = this->Body;
+ this->Body = FD->Body;
+ FD->Body = thisBody;
+
+ // Swap type information: this is important because in C, later
+ // declarations can provide slightly different types (enum vs. int,
+ // for example).
+ QualType thisType = this->getType();
+ this->setType(FD->getType());
+ FD->setType(thisType);
+
+ // Swap location information: this allows us to produce diagnostics
+ // later on that reference the most recent declaration (which has
+ // the most information!) while retaining the location of previous
+ // declarations (good for "redefinition" diagnostics).
+ SourceLocation thisLocation = this->getLocation();
+ this->setLocation(FD->getLocation());
+ FD->setLocation(thisLocation);
+
+ // Swap attributes. FD will have the union of the attributes from
+ // all previous declarations.
+ if (DeclAttrs) {
+ Attr *thisAttr = (*DeclAttrs)[this];
+ (*DeclAttrs)[this] = (*DeclAttrs)[FD];
+ (*DeclAttrs)[FD] = thisAttr;
+ }
+
+ // If any declaration is inline, the function is inline.
+ this->IsInline |= FD->IsInline;
+
+ // FIXME: Is this the right way to handle storage specifiers?
+ if (FD->SClass) this->SClass = FD->SClass;
+}
+
//===----------------------------------------------------------------------===//
// RecordDecl Implementation
//===----------------------------------------------------------------------===//
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 6d6a26d95d..e70da932f6 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -268,7 +268,8 @@ private:
TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
ScopedDecl *LastDecl);
TypedefDecl *MergeTypeDefDecl(TypedefDecl *New, Decl *Old);
- FunctionDecl *MergeFunctionDecl(FunctionDecl *New, Decl *Old);
+ FunctionDecl *MergeFunctionDecl(FunctionDecl *New, Decl *Old,
+ bool &Redeclaration);
VarDecl *MergeVarDecl(VarDecl *New, Decl *Old);
FunctionDecl *MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old);
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index eec8ce5d0a..415908a30b 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -256,8 +256,10 @@ static void MergeAttributes(Decl *New, Decl *Old) {
/// declarator D which has the same name and scope as a previous
/// declaration 'Old'. Figure out how to resolve this situation,
/// merging decls or emitting diagnostics as appropriate.
-///
-FunctionDecl *Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD) {
+/// Redeclaration will be set true if thisNew is a redeclaration OldD.
+FunctionDecl *
+Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD, bool &Redeclaration) {
+ Redeclaration = false;
// Verify the old decl was also a function.
FunctionDecl *Old = dyn_cast<FunctionDecl>(OldD);
if (!Old) {
@@ -267,28 +269,31 @@ FunctionDecl *Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD) {
return New;
}
- MergeAttributes(New, Old);
-
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());
// C++ [dcl.fct]p3:
// All declarations for a function shall agree exactly in both the
// return type and the parameter-type-list.
- if (getLangOptions().CPlusPlus && OldQType == NewQType)
+ if (getLangOptions().CPlusPlus && OldQType == NewQType) {
+ MergeAttributes(New, Old);
+ Redeclaration = true;
return MergeCXXFunctionDecl(New, Old);
+ }
// C: Function types need to be compatible, not identical. This handles
// duplicate function decls like "void f(int); void f(enum X);" properly.
if (!getLangOptions().CPlusPlus &&
Context.functionTypesAreCompatible(OldQType, NewQType)) {
+ MergeAttributes(New, Old);
+ Redeclaration = true;
return New;
}
// A function that has already been declared has been redeclared or defined
// with a different type- show appropriate diagnostic
diag::kind PrevDiag;
- if (Old->getBody())
+ if (Old->isThisDeclarationADefinition())
PrevDiag = diag::err_previous_definition;
else if (Old->isImplicit())
PrevDiag = diag::err_previous_implicit_declaration;
@@ -848,8 +853,18 @@ Sema::ActOnDeclarator(Scope *S, Declarator &D, DeclTy *lastDecl) {
// Merge the decl with the existing one if appropriate. Since C functions
// are in a flat namespace, make sure we consider decls in outer scopes.
if (PrevDecl) {
- NewFD = MergeFunctionDecl(NewFD, PrevDecl);
+ bool Redeclaration = false;
+ NewFD = MergeFunctionDecl(NewFD, PrevDecl, Redeclaration);
if (NewFD == 0) return 0;
+ if (Redeclaration) {
+ // Note that the new declaration is a redeclaration of the
+ // older declaration. Then return the older declaration: the
+ // new one is only kept within the set of previous
+ // declarations for this function.
+ FunctionDecl *OldFD = (FunctionDecl *)PrevDecl;
+ OldFD->AddRedeclaration(NewFD);
+ return OldFD;
+ }
}
New = NewFD;
@@ -1177,10 +1192,11 @@ Sema::DeclTy *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D) {
Decl *PrevDcl = LookupDecl(D.getIdentifier(), Decl::IDNS_Ordinary,
GlobalScope);
if (FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(PrevDcl)) {
- if (FD->getBody()) {
+ const FunctionDecl *Definition;
+ if (FD->getBody(Definition)) {
Diag(D.getIdentifierLoc(), diag::err_redefinition,
D.getIdentifier()->getName());
- Diag(FD->getLocation(), diag::err_previous_definition);
+ Diag(Definition->getLocation(), diag::err_previous_definition);
}
}
Decl *decl = static_cast<Decl*>(ActOnDeclarator(GlobalScope, D, 0));
diff --git a/test/Sema/redefinition.c b/test/Sema/redefinition.c
new file mode 100644
index 0000000000..c45779fdee
--- /dev/null
+++ b/test/Sema/redefinition.c
@@ -0,0 +1,5 @@
+// RUN: clang %s -fsyntax-only -verify
+int f(int) { } // expected-error{{previous definition is here}}
+int f(int);
+int f(int) { } // expected-error{{redefinition of 'f'}}
+
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