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Add a new expression classification, CL_AddressableVoid 

CL_AddressableVoid is the expression classification used for void
expressions whose address can be taken, i.e. the result of [], *
or void variable references in C, as opposed to things like the
result of a void function call.

llvm-svn: 129783
This commit is contained in:
Peter Collingbourne 2011-04-19 18:51:51 +00:00
parent 9ef4563c2a
commit 133587f08b
3 changed files with 21 additions and 4 deletions
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1
clang/include/clang/AST/Expr.h
View File

@ -221,6 +221,7 @@ public:
CL_XValue,
CL_Function, // Functions cannot be lvalues in C.
CL_Void, // Void cannot be an lvalue in C.
CL_AddressableVoid, // Void expression whose address can be taken in C.
CL_DuplicateVectorComponents, // A vector shuffle with dupes.
CL_MemberFunction, // An expression referring to a member function
CL_SubObjCPropertySetting,

13
clang/lib/AST/ExprClassification.cpp
View File

@ -61,8 +61,10 @@ Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
if (TR->isFunctionType() || TR == Ctx.OverloadTy)
kind = Cl::CL_Function;
// No void either, but qualified void is OK because it is "other than void".
else if (TR->isVoidType() && !Ctx.getCanonicalType(TR).hasQualifiers())
kind = Cl::CL_Void;
// Void "lvalues" are classified as addressable void values, which are void
// expressions whose address can be taken.
else if (TR->isVoidType() && !TR.hasQualifiers())
kind = (kind == Cl::CL_LValue ? Cl::CL_AddressableVoid : Cl::CL_Void);
}
// Enable this assertion for testing.
@ -71,6 +73,7 @@ Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
case Cl::CL_XValue: assert(getValueKind() == VK_XValue); break;
case Cl::CL_Function:
case Cl::CL_Void:
case Cl::CL_AddressableVoid:
case Cl::CL_DuplicateVectorComponents:
case Cl::CL_MemberFunction:
case Cl::CL_SubObjCPropertySetting:
@ -563,7 +566,8 @@ Expr::LValueClassification Expr::ClassifyLValue(ASTContext &Ctx) const {
case Cl::CL_LValue: return LV_Valid;
case Cl::CL_XValue: return LV_InvalidExpression;
case Cl::CL_Function: return LV_NotObjectType;
case Cl::CL_Void: return LV_IncompleteVoidType;
case Cl::CL_Void: return LV_InvalidExpression;
case Cl::CL_AddressableVoid: return LV_IncompleteVoidType;
case Cl::CL_DuplicateVectorComponents: return LV_DuplicateVectorComponents;
case Cl::CL_MemberFunction: return LV_MemberFunction;
case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting;
@ -582,7 +586,8 @@ Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const {
case Cl::CL_LValue: break;
case Cl::CL_XValue: return MLV_InvalidExpression;
case Cl::CL_Function: return MLV_NotObjectType;
case Cl::CL_Void: return MLV_IncompleteVoidType;
case Cl::CL_Void: return MLV_InvalidExpression;
case Cl::CL_AddressableVoid: return MLV_IncompleteVoidType;
case Cl::CL_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
case Cl::CL_MemberFunction: return MLV_MemberFunction;
case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting;

11
clang/test/Sema/expr-address-of.c
View File

@ -107,3 +107,14 @@ char* f7() {
void* t3 = &(*(void*)0);
}
void f8() {
void *dummy0 = &f8(); // expected-error {{address expression must be an lvalue or a function designator}}
extern void v;
void *dummy1 = &(1 ? v : f8()); // expected-error {{address expression must be an lvalue or a function designator}}
void *dummy2 = &(f8(), v); // expected-error {{address expression must be an lvalue or a function designator}}
void *dummy3 = &({ ; }); // expected-error {{address expression must be an lvalue or a function designator}}
}