Douglas Gregor wrote:
> Hi Chip,
>
> On Jan 4, 2010, at 3:13 PM, Charles Davis wrote:
>
>> Ping...
>>
>> Patch is reattached, rebased against current TOT.
>
> Thanks for your patience; comments below.
Sorry it took so long. Actually, the reason it took so long is that I
was on vacation :).
Anyway, latest patch reattached.
>
> With future patches, could you tweak Thunderbird to avoid inline
> attachments? There's rationale + directions here:
>
> http://llvm.org/docs/DeveloperPolicy.html#patches
Done.
>
>> /// isMoreQualifiedThan - Determine whether this type is more
>> /// qualified than the Other type. For example, "const volatile int"
>> /// is more qualified than "const int", "volatile int", and
>> Index: lib/Frontend/PCHWriter.cpp
>> ===================================================================
>> --- lib/Frontend/PCHWriter.cpp (revision 92538)
>> +++ lib/Frontend/PCHWriter.cpp (working copy)
>> @@ -139,6 +139,7 @@
>> void PCHTypeWriter::VisitFunctionType(const FunctionType *T) {
>> Writer.AddTypeRef(T->getResultType(), Record);
>> Record.push_back(T->getNoReturnAttr());
>> + Record.push_back(T->getCallConv());
>> }
>
> could you add a "// FIXME: stable encoding for calling convention" at
> the end of that push_back line? Some day, we'll need to divorce the bit
> encodings of all of our enums from the enum values (but not today!).
Done.
>
>> Index: lib/AST/ASTContext.cpp
>> ===================================================================
>> --- lib/AST/ASTContext.cpp (revision 92538)
>> +++ lib/AST/ASTContext.cpp (working copy)
>> @@ -1681,7 +1696,8 @@
>>
>> /// getFunctionNoProtoType - Return a K&R style C function type like
>> 'int()'.
>> ///
>> -QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool
>> NoReturn) {
>> +QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool
>> NoReturn,
>> + CallingConv CallConv) {
>> // Unique functions, to guarantee there is only one function of a
>> particular
>> // structure.
>> llvm::FoldingSetNodeID ID;
>> @@ -1694,7 +1710,8 @@
>>
>> QualType Canonical;
>> if (!ResultTy.isCanonical()) {
>> - Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy),
>> NoReturn);
>> + Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy),
>> NoReturn,
>> + CallConv);
>
> I'm not convinced that this is the correct formulation of the canonical
> type, because we may have to cope with the fact that the default calling
> convention is the same as the cdecl calling convention (always? for some
> targets? I don't know when). Here's a C++ example that should illustrate
> the issue:
>
> void __attribute__((cdecl)) f();
> void (*fp)() = &f;
>
> Here, the variable fp has the default calling convention but the its
> initializer, &f, has the cdecl calling convention. G++ accepts this code
> (but rejects similar code where the calling convention of f is stdcall),
> which indicates that it's considering the two types to be equivalent.
> So, we need to make sure that the canonical function type has a
> canonical representation of the calling convention, e.g., with a
> function like
>
> CallingConv ASTContext::getCanonicalCallingConv(CallingConv CC) {
> if (CC == CC_C)
> return CC_Default;
> return CC;
> }
>
> then, to build the canonical type, use
>
> if (!ResultTy.isCanonical() || getCanonicalCallingConv(CallConv) !=
> CallConv)
> Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy),
> NoReturn, getCanonicalCallingConv(CallConv));
>
You're absolutely right about that. I can't believe I overlooked that
case. When I added the default calling convention enumerator, I had in
mind that the default calling convention would be the same as C by
default, but could be changed. Apparently, I forgot to canonicalize the
default calling convention.
>> @@ -1746,7 +1764,7 @@
>> Canonical = getFunctionType(getCanonicalType(ResultTy),
>> CanonicalArgs.data(), NumArgs,
>> isVariadic, TypeQuals, false,
>> - false, 0, 0, NoReturn);
>> + false, 0, 0, NoReturn, CallConv);
>
> I have the same comment about using getCanonicalCallingConv here as above.
Done.
>
>> +static bool isCompatibleCallingConvention(CallingConv lcc,
>> CallingConv rcc) {
>> + // Here are the rules (as I see them) for compatibility of calling
>> + // conventions:
>> + // - If they're the same, they're compatible.
>> + // - If the first one is not the default and the second one is, then
>> + // they're compatible (and the second declaration assumes the
>> calling
>> + // convention of the first).
>> + // - Otherwise, they're not compatible.
>> + return (lcc == rcc || (lcc != CC_Default && rcc == CC_Default));
>> +}
>
> The order dependency on lcc/rcc doesn't make sense to me, since the
> definition of compatibility for types is commutative. I think the right
> implementation for this function is to compare the canonical calling
> conventions.
As I said the case I had in mind is this one:
void __attribute__((stdcall)) f(void);
void f(void) {}
or the equivalent MSVC:
void __stdcall f(void);
void f(void) {}
MSVC lets you do that. Oddly enough, I found that GCC doesn't let you do
that. Apparently, clang already handles that, so my concern was
unfounded. (Is it?) So, I changed it to just directly compare the
calling conventions, like you said it should.
>
> Aside from the canonical-types issue, I think this patch is ready to go
> in. Do you have commit access?
All right! ...But I don't have commit access yet. How do I get it? Or do
you intend to commit this yourself?
Chip
Index: include/clang/AST/ASTContext.h
===================================================================
--- include/clang/AST/ASTContext.h (revision 93367)
+++ include/clang/AST/ASTContext.h (working copy)
@@ -397,6 +397,11 @@
/// BlockPointer.
QualType getNoReturnType(QualType T, bool AddNoReturn = true);
+ /// getCallConvType - Adds the specified calling convention attribute to
+ /// the given type, which must be a FunctionType or a pointer to an
+ /// allowable type.
+ QualType getCallConvType(QualType T, CallingConv CallConv);
+
/// getComplexType - Return the uniqued reference to the type for a complex
/// number with the specified element type.
QualType getComplexType(QualType T);
@@ -513,7 +518,8 @@
/// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
///
- QualType getFunctionNoProtoType(QualType ResultTy, bool NoReturn = false);
+ QualType getFunctionNoProtoType(QualType ResultTy, bool NoReturn = false,
+ CallingConv CallConv = CC_Default);
/// getFunctionType - Return a normal function type with a typed argument
/// list. isVariadic indicates whether the argument list includes '...'.
@@ -522,7 +528,8 @@
unsigned TypeQuals, bool hasExceptionSpec = false,
bool hasAnyExceptionSpec = false,
unsigned NumExs = 0, const QualType *ExArray = 0,
- bool NoReturn = false);
+ bool NoReturn = false,
+ CallingConv CallConv = CC_Default);
/// getTypeDeclType - Return the unique reference to the type for
/// the specified type declaration.
Index: include/clang/AST/Type.h
===================================================================
--- include/clang/AST/Type.h (revision 93367)
+++ include/clang/AST/Type.h (working copy)
@@ -385,7 +385,15 @@
}
};
+/// CallingConv - Specifies the calling convention that a function uses.
+enum CallingConv {
+ CC_Default,
+ CC_C, // __attribute__((cdecl))
+ CC_X86StdCall, // __attribute__((stdcall))
+ CC_X86FastCall // __attribute__((fastcall))
+};
+
/// QualType - For efficiency, we don't store CV-qualified types as nodes on
/// their own: instead each reference to a type stores the qualifiers. This
/// greatly reduces the number of nodes we need to allocate for types (for
@@ -669,6 +677,10 @@
/// false otherwise.
bool getNoReturnAttr() const;
+ /// getCallConv - Returns the calling convention of the type if the type
+ /// is a function type, CC_Default otherwise.
+ CallingConv getCallConv() const;
+
private:
// These methods are implemented in a separate translation unit;
// "static"-ize them to avoid creating temporary QualTypes in the
@@ -1691,21 +1703,25 @@
/// NoReturn - Indicates if the function type is attribute noreturn.
unsigned NoReturn : 1;
+ /// CallConv - The calling convention used by the function.
+ unsigned CallConv : 2;
+
// The type returned by the function.
QualType ResultType;
protected:
FunctionType(TypeClass tc, QualType res, bool SubclassInfo,
unsigned typeQuals, QualType Canonical, bool Dependent,
- bool noReturn = false)
+ bool noReturn = false, CallingConv callConv = CC_Default)
: Type(tc, Canonical, Dependent),
SubClassData(SubclassInfo), TypeQuals(typeQuals), NoReturn(noReturn),
- ResultType(res) {}
+ CallConv(callConv), ResultType(res) {}
bool getSubClassData() const { return SubClassData; }
unsigned getTypeQuals() const { return TypeQuals; }
public:
QualType getResultType() const { return ResultType; }
bool getNoReturnAttr() const { return NoReturn; }
+ CallingConv getCallConv() const { return (CallingConv)CallConv; }
static bool classof(const Type *T) {
return T->getTypeClass() == FunctionNoProto ||
@@ -1718,9 +1734,9 @@
/// no information available about its arguments.
class FunctionNoProtoType : public FunctionType, public llvm::FoldingSetNode {
FunctionNoProtoType(QualType Result, QualType Canonical,
- bool NoReturn = false)
+ bool NoReturn = false, CallingConv CallConv = CC_Default)
: FunctionType(FunctionNoProto, Result, false, 0, Canonical,
- /*Dependent=*/false, NoReturn) {}
+ /*Dependent=*/false, NoReturn, CallConv) {}
friend class ASTContext; // ASTContext creates these.
public:
// No additional state past what FunctionType provides.
@@ -1762,10 +1778,12 @@
FunctionProtoType(QualType Result, const QualType *ArgArray, unsigned
numArgs,
bool isVariadic, unsigned typeQuals, bool hasExs,
bool hasAnyExs, const QualType *ExArray,
- unsigned numExs, QualType Canonical, bool NoReturn)
+ unsigned numExs, QualType Canonical, bool NoReturn,
+ CallingConv CallConv)
: FunctionType(FunctionProto, Result, isVariadic, typeQuals, Canonical,
(Result->isDependentType() ||
- hasAnyDependentType(ArgArray, numArgs)), NoReturn),
+ hasAnyDependentType(ArgArray, numArgs)), NoReturn,
+ CallConv),
NumArgs(numArgs), NumExceptions(numExs), HasExceptionSpec(hasExs),
AnyExceptionSpec(hasAnyExs) {
// Fill in the trailing argument array.
@@ -2797,6 +2815,26 @@
return false;
}
+/// getCallConv - Returns the calling convention of the type if the type
+/// is a function type, CC_Default otherwise.
+inline CallingConv QualType::getCallConv() const {
+ if (const PointerType *PT = getTypePtr()->getAs<PointerType>())
+ return PT->getPointeeType().getCallConv();
+ else if (const ReferenceType *RT = getTypePtr()->getAs<ReferenceType>())
+ return RT->getPointeeType().getCallConv();
+ else if (const MemberPointerType *MPT =
+ getTypePtr()->getAs<MemberPointerType>())
+ return MPT->getPointeeType().getCallConv();
+ else if (const BlockPointerType *BPT =
+ getTypePtr()->getAs<BlockPointerType>()) {
+ if (const FunctionType *FT = BPT->getPointeeType()->getAs<FunctionType>())
+ return FT->getCallConv();
+ } else if (const FunctionType *FT = getTypePtr()->getAs<FunctionType>())
+ return FT->getCallConv();
+
+ return CC_Default;
+}
+
/// isMoreQualifiedThan - Determine whether this type is more
/// qualified than the Other type. For example, "const volatile int"
/// is more qualified than "const int", "volatile int", and
Index: lib/Frontend/PCHWriter.cpp
===================================================================
--- lib/Frontend/PCHWriter.cpp (revision 93367)
+++ lib/Frontend/PCHWriter.cpp (working copy)
@@ -139,6 +139,8 @@
void PCHTypeWriter::VisitFunctionType(const FunctionType *T) {
Writer.AddTypeRef(T->getResultType(), Record);
Record.push_back(T->getNoReturnAttr());
+ // FIXME: need to stabilize encoding of calling convention...
+ Record.push_back(T->getCallConv());
}
void PCHTypeWriter::VisitFunctionNoProtoType(const FunctionNoProtoType *T) {
Index: lib/Frontend/PCHReader.cpp
===================================================================
--- lib/Frontend/PCHReader.cpp (revision 93367)
+++ lib/Frontend/PCHReader.cpp (working copy)
@@ -1909,18 +1909,20 @@
}
case pch::TYPE_FUNCTION_NO_PROTO: {
- if (Record.size() != 2) {
+ if (Record.size() != 3) {
Error("incorrect encoding of no-proto function type");
return QualType();
}
QualType ResultType = GetType(Record[0]);
- return Context->getFunctionNoProtoType(ResultType, Record[1]);
+ return Context->getFunctionNoProtoType(ResultType, Record[1],
+ (CallingConv)Record[2]);
}
case pch::TYPE_FUNCTION_PROTO: {
QualType ResultType = GetType(Record[0]);
bool NoReturn = Record[1];
- unsigned Idx = 2;
+ CallingConv CallConv = (CallingConv)Record[2];
+ unsigned Idx = 3;
unsigned NumParams = Record[Idx++];
llvm::SmallVector<QualType, 16> ParamTypes;
for (unsigned I = 0; I != NumParams; ++I)
@@ -1936,7 +1938,7 @@
return Context->getFunctionType(ResultType, ParamTypes.data(), NumParams,
isVariadic, Quals, hasExceptionSpec,
hasAnyExceptionSpec, NumExceptions,
- Exceptions.data(), NoReturn);
+ Exceptions.data(), NoReturn, CallConv);
}
case pch::TYPE_UNRESOLVED_USING:
Index: lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiateDecl.cpp (revision 93367)
+++ lib/Sema/SemaTemplateInstantiateDecl.cpp (working copy)
@@ -1542,7 +1542,8 @@
Proto->hasAnyExceptionSpec(),
Exceptions.size(),
Exceptions.data(),
- Proto->getNoReturnAttr()));
+ Proto->getNoReturnAttr(),
+ Proto->getCallConv()));
}
return false;
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp (revision 93367)
+++ lib/AST/ASTContext.cpp (working copy)
@@ -1200,45 +1200,60 @@
return getExtQualType(TypeNode, Quals);
}
-QualType ASTContext::getNoReturnType(QualType T, bool AddNoReturn) {
+static QualType getNoReturnCallConvType(ASTContext& Context, QualType T,
+ bool AddNoReturn,
+ CallingConv CallConv) {
QualType ResultType;
if (const PointerType *Pointer = T->getAs<PointerType>()) {
QualType Pointee = Pointer->getPointeeType();
- ResultType = getNoReturnType(Pointee, AddNoReturn);
+ ResultType = getNoReturnCallConvType(Context, Pointee, AddNoReturn,
+ CallConv);
if (ResultType == Pointee)
return T;
-
- ResultType = getPointerType(ResultType);
+
+ ResultType = Context.getPointerType(ResultType);
} else if (const BlockPointerType *BlockPointer
= T->getAs<BlockPointerType>()) {
QualType Pointee = BlockPointer->getPointeeType();
- ResultType = getNoReturnType(Pointee, AddNoReturn);
+ ResultType = getNoReturnCallConvType(Context, Pointee, AddNoReturn,
+ CallConv);
if (ResultType == Pointee)
return T;
-
- ResultType = getBlockPointerType(ResultType);
- } else if (const FunctionType *F = T->getAs<FunctionType>()) {
- if (F->getNoReturnAttr() == AddNoReturn)
+
+ ResultType = Context.getBlockPointerType(ResultType);
+ } else if (const FunctionType *F = T->getAs<FunctionType>()) {
+ if (F->getNoReturnAttr() == AddNoReturn && F->getCallConv() == CallConv)
return T;
-
+
if (const FunctionNoProtoType *FNPT = dyn_cast<FunctionNoProtoType>(F)) {
- ResultType = getFunctionNoProtoType(FNPT->getResultType(), AddNoReturn);
+ ResultType = Context.getFunctionNoProtoType(FNPT->getResultType(),
+ AddNoReturn, CallConv);
} else {
const FunctionProtoType *FPT = cast<FunctionProtoType>(F);
ResultType
- = getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
- FPT->getNumArgs(), FPT->isVariadic(),
- FPT->getTypeQuals(),
- FPT->hasExceptionSpec(), FPT->hasAnyExceptionSpec(),
- FPT->getNumExceptions(), FPT->exception_begin(),
- AddNoReturn);
+ = Context.getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
+ FPT->getNumArgs(), FPT->isVariadic(),
+ FPT->getTypeQuals(),
+ FPT->hasExceptionSpec(),
+ FPT->hasAnyExceptionSpec(),
+ FPT->getNumExceptions(),
+ FPT->exception_begin(),
+ AddNoReturn, CallConv);
}
} else
return T;
-
- return getQualifiedType(ResultType, T.getLocalQualifiers());
+
+ return Context.getQualifiedType(ResultType, T.getLocalQualifiers());
}
+QualType ASTContext::getNoReturnType(QualType T, bool AddNoReturn) {
+ return getNoReturnCallConvType(*this, T, AddNoReturn, T.getCallConv());
+}
+
+QualType ASTContext::getCallConvType(QualType T, CallingConv CallConv) {
+ return getNoReturnCallConvType(*this, T, T.getNoReturnAttr(), CallConv);
+}
+
/// getComplexType - Return the uniqued reference to the type for a complex
/// number with the specified element type.
QualType ASTContext::getComplexType(QualType T) {
@@ -1679,9 +1694,16 @@
return QualType(New, 0);
}
+static CallingConv getCanonicalCallingConv(CallingConv CC) {
+ if (CC == CC_C)
+ return CC_Default;
+ return CC;
+}
+
/// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
///
-QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool NoReturn) {
+QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool NoReturn,
+ CallingConv CallConv) {
// Unique functions, to guarantee there is only one function of a particular
// structure.
llvm::FoldingSetNodeID ID;
@@ -1693,8 +1715,10 @@
return QualType(FT, 0);
QualType Canonical;
- if (!ResultTy.isCanonical()) {
- Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy), NoReturn);
+ if (!ResultTy.isCanonical() ||
+ getCanonicalCallingConv(CallConv) != CallConv) {
+ Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy), NoReturn,
+ getCanonicalCallingConv(CallConv));
// Get the new insert position for the node we care about.
FunctionNoProtoType *NewIP =
@@ -1715,7 +1739,8 @@
unsigned NumArgs, bool isVariadic,
unsigned TypeQuals, bool hasExceptionSpec,
bool hasAnyExceptionSpec, unsigned NumExs,
- const QualType *ExArray, bool NoReturn) {
+ const QualType *ExArray, bool NoReturn,
+ CallingConv CallConv) {
// Unique functions, to guarantee there is only one function of a particular
// structure.
llvm::FoldingSetNodeID ID;
@@ -1737,7 +1762,7 @@
// If this type isn't canonical, get the canonical version of it.
// The exception spec is not part of the canonical type.
QualType Canonical;
- if (!isCanonical) {
+ if (!isCanonical || getCanonicalCallingConv(CallConv) != CallConv) {
llvm::SmallVector<QualType, 16> CanonicalArgs;
CanonicalArgs.reserve(NumArgs);
for (unsigned i = 0; i != NumArgs; ++i)
@@ -1746,7 +1771,8 @@
Canonical = getFunctionType(getCanonicalType(ResultTy),
CanonicalArgs.data(), NumArgs,
isVariadic, TypeQuals, false,
- false, 0, 0, NoReturn);
+ false, 0, 0, NoReturn,
+ getCanonicalCallingConv(CallConv));
// Get the new insert position for the node we care about.
FunctionProtoType *NewIP =
@@ -1763,7 +1789,7 @@
NumExs*sizeof(QualType), TypeAlignment);
new (FTP) FunctionProtoType(ResultTy, ArgArray, NumArgs, isVariadic,
TypeQuals, hasExceptionSpec, hasAnyExceptionSpec,
- ExArray, NumExs, Canonical, NoReturn);
+ ExArray, NumExs, Canonical, NoReturn, CallConv);
Types.push_back(FTP);
FunctionProtoTypes.InsertNode(FTP, InsertPos);
return QualType(FTP, 0);
@@ -4211,6 +4237,10 @@
return !mergeTypes(LHS, RHS).isNull();
}
+static bool isSameCallingConvention(CallingConv lcc, CallingConv rcc) {
+ return (lcc == rcc);
+}
+
QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
const FunctionType *lbase = lhs->getAs<FunctionType>();
const FunctionType *rbase = rhs->getAs<FunctionType>();
@@ -4232,6 +4262,11 @@
allLTypes = false;
if (NoReturn != rbase->getNoReturnAttr())
allRTypes = false;
+ CallingConv lcc = lbase->getCallConv();
+ CallingConv rcc = rbase->getCallConv();
+ // Compatible functions must have compatible calling conventions
+ if (!isSameCallingConvention(lcc, rcc))
+ return QualType();
if (lproto && rproto) { // two C99 style function prototypes
assert(!lproto->hasExceptionSpec() && !rproto->hasExceptionSpec() &&
@@ -4267,7 +4302,7 @@
if (allRTypes) return rhs;
return getFunctionType(retType, types.begin(), types.size(),
lproto->isVariadic(), lproto->getTypeQuals(),
- NoReturn);
+ NoReturn, lcc);
}
if (lproto) allRTypes = false;
@@ -4294,12 +4329,12 @@
if (allRTypes) return rhs;
return getFunctionType(retType, proto->arg_type_begin(),
proto->getNumArgs(), proto->isVariadic(),
- proto->getTypeQuals(), NoReturn);
+ proto->getTypeQuals(), NoReturn, lcc);
}
if (allLTypes) return lhs;
if (allRTypes) return rhs;
- return getFunctionNoProtoType(retType, NoReturn);
+ return getFunctionNoProtoType(retType, NoReturn, lcc);
}
QualType ASTContext::mergeTypes(QualType LHS, QualType RHS) {
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