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llvm-project/clang/lib/Sema/SemaInit.cpp
Douglas Gregor 0202cb406e Introduce a new expression node, ImplicitValueInitExpr, that 
represents an implicit value-initialization of a subobject of a
particular type. This replaces the (ab)use of CXXZeroValueInitExpr
within initializer lists for the "holes" that occur due to the use of
C99 designated initializers.

The new test case is currently XFAIL'd, because CodeGen's
ConstExprEmitter (in lib/CodeGen/CGExprConstant.cpp) needs to be
taught to value-initialize when it sees ImplicitValueInitExprs.

llvm-svn: 63317
2009-01-29 17:44:32 +00:00

1137 lines
45 KiB
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//===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for initializers. The entry
// point is Sema::CheckInitList(), but all of the work is performed
// within the InitListChecker class.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "clang/Parse/Designator.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
#include <map>
using namespace clang;
/// @brief Semantic checking for initializer lists.
///
/// The InitListChecker class contains a set of routines that each
/// handle the initialization of a certain kind of entity, e.g.,
/// arrays, vectors, struct/union types, scalars, etc. The
/// InitListChecker itself performs a recursive walk of the subobject
/// structure of the type to be initialized, while stepping through
/// the initializer list one element at a time. The IList and Index
/// parameters to each of the Check* routines contain the active
/// (syntactic) initializer list and the index into that initializer
/// list that represents the current initializer. Each routine is
/// responsible for moving that Index forward as it consumes elements.
///
/// Each Check* routine also has a StructuredList/StructuredIndex
/// arguments, which contains the current the "structured" (semantic)
/// initializer list and the index into that initializer list where we
/// are copying initializers as we map them over to the semantic
/// list. Once we have completed our recursive walk of the subobject
/// structure, we will have constructed a full semantic initializer
/// list.
///
/// C99 designators cause changes in the initializer list traversal,
/// because they make the initialization "jump" into a specific
/// subobject and then continue the initialization from that
/// point. CheckDesignatedInitializer() recursively steps into the
/// designated subobject and manages backing out the recursion to
/// initialize the subobjects after the one designated.
namespace clang {
class InitListChecker {
Sema *SemaRef;
bool hadError;
std::map<InitListExpr *, InitListExpr *> SyntacticToSemantic;
InitListExpr *FullyStructuredList;
void CheckImplicitInitList(InitListExpr *ParentIList, QualType T,
unsigned &Index, InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckExplicitInitList(InitListExpr *IList, QualType &T,
unsigned &Index, InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckListElementTypes(InitListExpr *IList, QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckSubElementType(InitListExpr *IList, QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
// FIXME: Does DeclType need to be a reference type?
void CheckScalarType(InitListExpr *IList, QualType &DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckVectorType(InitListExpr *IList, QualType DeclType, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckStructUnionTypes(InitListExpr *IList, QualType DeclType,
RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckArrayType(InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
bool CheckDesignatedInitializer(InitListExpr *IList, DesignatedInitExpr *DIE,
DesignatedInitExpr::designators_iterator D,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit = true);
InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
unsigned StructuredIndex,
SourceRange InitRange);
void UpdateStructuredListElement(InitListExpr *StructuredList,
unsigned &StructuredIndex,
Expr *expr);
int numArrayElements(QualType DeclType);
int numStructUnionElements(QualType DeclType);
public:
InitListChecker(Sema *S, InitListExpr *IL, QualType &T);
bool HadError() { return hadError; }
// @brief Retrieves the fully-structured initializer list used for
// semantic analysis and code generation.
InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
};
}
/// Recursively replaces NULL values within the given initializer list
/// with expressions that perform value-initialization of the
/// appropriate type.
static void fillInValueInitializations(ASTContext &Context, InitListExpr *ILE) {
assert((ILE->getType() != Context.VoidTy) && "Should not have void type");
if (const RecordType *RType = ILE->getType()->getAsRecordType()) {
unsigned Init = 0, NumInits = ILE->getNumInits();
for (RecordDecl::field_iterator Field = RType->getDecl()->field_begin(),
FieldEnd = RType->getDecl()->field_end();
Field != FieldEnd; ++Field) {
if (Field->isUnnamedBitfield())
continue;
if (Init >= NumInits)
break;
// FIXME: Check for fields with reference type in C++?
if (!ILE->getInit(Init))
ILE->setInit(Init,
new (Context) ImplicitValueInitExpr(Field->getType()));
else if (InitListExpr *InnerILE
= dyn_cast<InitListExpr>(ILE->getInit(Init)))
fillInValueInitializations(Context, InnerILE);
++Init;
}
return;
}
QualType ElementType;
if (const ArrayType *AType = Context.getAsArrayType(ILE->getType()))
ElementType = AType->getElementType();
else if (const VectorType *VType = ILE->getType()->getAsVectorType())
ElementType = VType->getElementType();
else
ElementType = ILE->getType();
for (unsigned Init = 0, NumInits = ILE->getNumInits(); Init != NumInits;
++Init) {
if (!ILE->getInit(Init))
ILE->setInit(Init, new (Context) ImplicitValueInitExpr(ElementType));
else if (InitListExpr *InnerILE =dyn_cast<InitListExpr>(ILE->getInit(Init)))
fillInValueInitializations(Context, InnerILE);
}
}
InitListChecker::InitListChecker(Sema *S, InitListExpr *IL, QualType &T) {
hadError = false;
SemaRef = S;
unsigned newIndex = 0;
unsigned newStructuredIndex = 0;
FullyStructuredList
= getStructuredSubobjectInit(IL, newIndex, T, 0, 0, SourceRange());
CheckExplicitInitList(IL, T, newIndex, FullyStructuredList, newStructuredIndex);
if (!hadError) {
fillInValueInitializations(SemaRef->Context, FullyStructuredList);
}
}
int InitListChecker::numArrayElements(QualType DeclType) {
// FIXME: use a proper constant
int maxElements = 0x7FFFFFFF;
if (const ConstantArrayType *CAT =
SemaRef->Context.getAsConstantArrayType(DeclType)) {
maxElements = static_cast<int>(CAT->getSize().getZExtValue());
}
return maxElements;
}
int InitListChecker::numStructUnionElements(QualType DeclType) {
RecordDecl *structDecl = DeclType->getAsRecordType()->getDecl();
int InitializableMembers = 0;
for (RecordDecl::field_iterator Field = structDecl->field_begin(),
FieldEnd = structDecl->field_end();
Field != FieldEnd; ++Field) {
if ((*Field)->getIdentifier() || !(*Field)->isBitField())
++InitializableMembers;
}
if (structDecl->isUnion())
return std::min(InitializableMembers, 1);
return InitializableMembers - structDecl->hasFlexibleArrayMember();
}
void InitListChecker::CheckImplicitInitList(InitListExpr *ParentIList,
QualType T, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
int maxElements = 0;
if (T->isArrayType())
maxElements = numArrayElements(T);
else if (T->isStructureType() || T->isUnionType())
maxElements = numStructUnionElements(T);
else if (T->isVectorType())
maxElements = T->getAsVectorType()->getNumElements();
else
assert(0 && "CheckImplicitInitList(): Illegal type");
// FIXME: Perhaps we should move this warning elsewhere?
if (maxElements == 0) {
SemaRef->Diag(ParentIList->getInit(Index)->getLocStart(),
diag::err_implicit_empty_initializer);
++Index;
hadError = true;
return;
}
// Build a structured initializer list corresponding to this subobject.
InitListExpr *StructuredSubobjectInitList
= getStructuredSubobjectInit(ParentIList, Index, T, StructuredList,
StructuredIndex,
ParentIList->getInit(Index)->getSourceRange());
unsigned StructuredSubobjectInitIndex = 0;
// Check the element types and build the structural subobject.
CheckListElementTypes(ParentIList, T, false, Index,
StructuredSubobjectInitList,
StructuredSubobjectInitIndex);
}
void InitListChecker::CheckExplicitInitList(InitListExpr *IList, QualType &T,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
assert(IList->isExplicit() && "Illegal Implicit InitListExpr");
SyntacticToSemantic[IList] = StructuredList;
StructuredList->setSyntacticForm(IList);
CheckListElementTypes(IList, T, true, Index, StructuredList,
StructuredIndex);
IList->setType(T);
StructuredList->setType(T);
if (hadError)
return;
if (Index < IList->getNumInits()) {
// We have leftover initializers
if (IList->getNumInits() > 0 &&
SemaRef->IsStringLiteralInit(IList->getInit(Index), T)) {
// Special-case
SemaRef->Diag(IList->getInit(Index)->getLocStart(),
diag::err_excess_initializers_in_char_array_initializer)
<< IList->getInit(Index)->getSourceRange();
hadError = true;
} else if (!T->isIncompleteType()) {
// Don't warn for incomplete types, since we'll get an error elsewhere
SemaRef->Diag(IList->getInit(Index)->getLocStart(),
diag::warn_excess_initializers)
<< IList->getInit(Index)->getSourceRange();
}
}
if (T->isScalarType())
SemaRef->Diag(IList->getLocStart(), diag::warn_braces_around_scalar_init)
<< IList->getSourceRange();
}
void InitListChecker::CheckListElementTypes(InitListExpr *IList,
QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (DeclType->isScalarType()) {
CheckScalarType(IList, DeclType, Index, StructuredList, StructuredIndex);
} else if (DeclType->isVectorType()) {
CheckVectorType(IList, DeclType, Index, StructuredList, StructuredIndex);
} else if (DeclType->isAggregateType() || DeclType->isUnionType()) {
if (DeclType->isStructureType() || DeclType->isUnionType()) {
RecordDecl *RD = DeclType->getAsRecordType()->getDecl();
CheckStructUnionTypes(IList, DeclType, RD->field_begin(),
SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isArrayType()) {
llvm::APSInt Zero(
SemaRef->Context.getTypeSize(SemaRef->Context.getSizeType()),
false);
CheckArrayType(IList, DeclType, Zero, SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
}
else
assert(0 && "Aggregate that isn't a structure or array?!");
} else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
// This type is invalid, issue a diagnostic.
++Index;
SemaRef->Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
<< DeclType;
hadError = true;
} else {
// In C, all types are either scalars or aggregates, but
// additional handling is needed here for C++ (and possibly others?).
assert(0 && "Unsupported initializer type");
}
}
void InitListChecker::CheckSubElementType(InitListExpr *IList,
QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
Expr *expr = IList->getInit(Index);
if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
unsigned newIndex = 0;
unsigned newStructuredIndex = 0;
InitListExpr *newStructuredList
= getStructuredSubobjectInit(IList, Index, ElemType,
StructuredList, StructuredIndex,
SubInitList->getSourceRange());
CheckExplicitInitList(SubInitList, ElemType, newIndex,
newStructuredList, newStructuredIndex);
++StructuredIndex;
++Index;
} else if (StringLiteral *lit =
SemaRef->IsStringLiteralInit(expr, ElemType)) {
SemaRef->CheckStringLiteralInit(lit, ElemType);
UpdateStructuredListElement(StructuredList, StructuredIndex, lit);
++Index;
} else if (ElemType->isScalarType()) {
CheckScalarType(IList, ElemType, Index, StructuredList, StructuredIndex);
} else if (expr->getType()->getAsRecordType() &&
SemaRef->Context.typesAreCompatible(
expr->getType().getUnqualifiedType(),
ElemType.getUnqualifiedType())) {
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
// FIXME: Add checking
} else {
CheckImplicitInitList(IList, ElemType, Index, StructuredList,
StructuredIndex);
++StructuredIndex;
}
}
void InitListChecker::CheckScalarType(InitListExpr *IList, QualType &DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index < IList->getNumInits()) {
Expr *expr = IList->getInit(Index);
if (isa<InitListExpr>(expr)) {
SemaRef->Diag(IList->getLocStart(),
diag::err_many_braces_around_scalar_init)
<< IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
} else if (isa<DesignatedInitExpr>(expr)) {
SemaRef->Diag(expr->getSourceRange().getBegin(),
diag::err_designator_for_scalar_init)
<< DeclType << expr->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
Expr *savExpr = expr; // Might be promoted by CheckSingleInitializer.
if (SemaRef->CheckSingleInitializer(expr, DeclType, false))
hadError = true; // types weren't compatible.
else if (savExpr != expr) {
// The type was promoted, update initializer list.
IList->setInit(Index, expr);
}
if (hadError)
++StructuredIndex;
else
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
} else {
SemaRef->Diag(IList->getLocStart(), diag::err_empty_scalar_initializer)
<< IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
}
void InitListChecker::CheckVectorType(InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index < IList->getNumInits()) {
const VectorType *VT = DeclType->getAsVectorType();
int maxElements = VT->getNumElements();
QualType elementType = VT->getElementType();
for (int i = 0; i < maxElements; ++i) {
// Don't attempt to go past the end of the init list
if (Index >= IList->getNumInits())
break;
CheckSubElementType(IList, elementType, Index,
StructuredList, StructuredIndex);
}
}
}
void InitListChecker::CheckArrayType(InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
// Check for the special-case of initializing an array with a string.
if (Index < IList->getNumInits()) {
if (StringLiteral *lit =
SemaRef->IsStringLiteralInit(IList->getInit(Index), DeclType)) {
SemaRef->CheckStringLiteralInit(lit, DeclType);
// We place the string literal directly into the resulting
// initializer list. This is the only place where the structure
// of the structured initializer list doesn't match exactly,
// because doing so would involve allocating one character
// constant for each string.
UpdateStructuredListElement(StructuredList, StructuredIndex, lit);
StructuredList->resizeInits(SemaRef->Context, StructuredIndex);
++Index;
return;
}
}
if (const VariableArrayType *VAT =
SemaRef->Context.getAsVariableArrayType(DeclType)) {
// Check for VLAs; in standard C it would be possible to check this
// earlier, but I don't know where clang accepts VLAs (gcc accepts
// them in all sorts of strange places).
SemaRef->Diag(VAT->getSizeExpr()->getLocStart(),
diag::err_variable_object_no_init)
<< VAT->getSizeExpr()->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
// We might know the maximum number of elements in advance.
llvm::APSInt maxElements(elementIndex.getBitWidth(),
elementIndex.isUnsigned());
bool maxElementsKnown = false;
if (const ConstantArrayType *CAT =
SemaRef->Context.getAsConstantArrayType(DeclType)) {
maxElements = CAT->getSize();
elementIndex.extOrTrunc(maxElements.getBitWidth());
elementIndex.setIsUnsigned(maxElements.isUnsigned());
maxElementsKnown = true;
}
QualType elementType = SemaRef->Context.getAsArrayType(DeclType)
->getElementType();
while (Index < IList->getNumInits()) {
Expr *Init = IList->getInit(Index);
if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
// If we're not the subobject that matches up with the '{' for
// the designator, we shouldn't be handling the
// designator. Return immediately.
if (!SubobjectIsDesignatorContext)
return;
// Handle this designated initializer. elementIndex will be
// updated to be the next array element we'll initialize.
if (CheckDesignatedInitializer(IList, DIE, DIE->designators_begin(),
DeclType, 0, &elementIndex, Index,
StructuredList, StructuredIndex)) {
hadError = true;
continue;
}
if (elementIndex.getBitWidth() > maxElements.getBitWidth())
maxElements.extend(elementIndex.getBitWidth());
else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
elementIndex.extend(maxElements.getBitWidth());
elementIndex.setIsUnsigned(maxElements.isUnsigned());
// If the array is of incomplete type, keep track of the number of
// elements in the initializer.
if (!maxElementsKnown && elementIndex > maxElements)
maxElements = elementIndex;
continue;
}
// If we know the maximum number of elements, and we've already
// hit it, stop consuming elements in the initializer list.
if (maxElementsKnown && elementIndex == maxElements)
break;
// Check this element.
CheckSubElementType(IList, elementType, Index,
StructuredList, StructuredIndex);
++elementIndex;
// If the array is of incomplete type, keep track of the number of
// elements in the initializer.
if (!maxElementsKnown && elementIndex > maxElements)
maxElements = elementIndex;
}
if (DeclType->isIncompleteArrayType()) {
// If this is an incomplete array type, the actual type needs to
// be calculated here.
llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
if (maxElements == Zero) {
// Sizing an array implicitly to zero is not allowed by ISO C,
// but is supported by GNU.
SemaRef->Diag(IList->getLocStart(),
diag::ext_typecheck_zero_array_size);
}
DeclType = SemaRef->Context.getConstantArrayType(elementType, maxElements,
ArrayType::Normal, 0);
}
}
void InitListChecker::CheckStructUnionTypes(InitListExpr *IList,
QualType DeclType,
RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
RecordDecl* structDecl = DeclType->getAsRecordType()->getDecl();
// If the record is invalid, some of it's members are invalid. To avoid
// confusion, we forgo checking the intializer for the entire record.
if (structDecl->isInvalidDecl()) {
hadError = true;
return;
}
if (DeclType->isUnionType() && IList->getNumInits() == 0) {
// Value-initialize the first named member of the union.
RecordDecl *RD = DeclType->getAsRecordType()->getDecl();
for (RecordDecl::field_iterator FieldEnd = RD->field_end();
Field != FieldEnd; ++Field) {
if (Field->getDeclName()) {
StructuredList->setInitializedFieldInUnion(*Field);
break;
}
}
return;
}
// If structDecl is a forward declaration, this loop won't do
// anything except look at designated initializers; That's okay,
// because an error should get printed out elsewhere. It might be
// worthwhile to skip over the rest of the initializer, though.
RecordDecl *RD = DeclType->getAsRecordType()->getDecl();
RecordDecl::field_iterator FieldEnd = RD->field_end();
while (Index < IList->getNumInits()) {
Expr *Init = IList->getInit(Index);
if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
// If we're not the subobject that matches up with the '{' for
// the designator, we shouldn't be handling the
// designator. Return immediately.
if (!SubobjectIsDesignatorContext)
return;
// Handle this designated initializer. Field will be updated to
// the next field that we'll be initializing.
if (CheckDesignatedInitializer(IList, DIE, DIE->designators_begin(),
DeclType, &Field, 0, Index,
StructuredList, StructuredIndex))
hadError = true;
// Abort early for unions: the designator handled the
// initialization of the appropriate field.
if (DeclType->isUnionType())
break;
continue;
}
if (Field == FieldEnd) {
// We've run out of fields. We're done.
break;
}
// If we've hit the flexible array member at the end, we're done.
if (Field->getType()->isIncompleteArrayType())
break;
if (Field->isUnnamedBitfield()) {
// Don't initialize unnamed bitfields, e.g. "int : 20;"
++Field;
continue;
}
CheckSubElementType(IList, Field->getType(), Index,
StructuredList, StructuredIndex);
if (DeclType->isUnionType()) {
// Initialize the first field within the union.
StructuredList->setInitializedFieldInUnion(*Field);
break;
}
++Field;
}
// FIXME: Implement flexible array initialization GCC extension (it's a
// really messy extension to implement, unfortunately...the necessary
// information isn't actually even here!)
}
/// @brief Check the well-formedness of a C99 designated initializer.
///
/// Determines whether the designated initializer @p DIE, which
/// resides at the given @p Index within the initializer list @p
/// IList, is well-formed for a current object of type @p DeclType
/// (C99 6.7.8). The actual subobject that this designator refers to
/// within the current subobject is returned in either
/// @p NextField or @p NextElementIndex (whichever is appropriate).
///
/// @param IList The initializer list in which this designated
/// initializer occurs.
///
/// @param DIE The designated initializer and its initialization
/// expression.
///
/// @param DeclType The type of the "current object" (C99 6.7.8p17),
/// into which the designation in @p DIE should refer.
///
/// @param NextField If non-NULL and the first designator in @p DIE is
/// a field, this will be set to the field declaration corresponding
/// to the field named by the designator.
///
/// @param NextElementIndex If non-NULL and the first designator in @p
/// DIE is an array designator or GNU array-range designator, this
/// will be set to the last index initialized by this designator.
///
/// @param Index Index into @p IList where the designated initializer
/// @p DIE occurs.
///
/// @param StructuredList The initializer list expression that
/// describes all of the subobject initializers in the order they'll
/// actually be initialized.
///
/// @returns true if there was an error, false otherwise.
bool
InitListChecker::CheckDesignatedInitializer(InitListExpr *IList,
DesignatedInitExpr *DIE,
DesignatedInitExpr::designators_iterator D,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit) {
if (D == DIE->designators_end()) {
// Check the actual initialization for the designated object type.
bool prevHadError = hadError;
// Temporarily remove the designator expression from the
// initializer list that the child calls see, so that we don't try
// to re-process the designator.
unsigned OldIndex = Index;
IList->setInit(OldIndex, DIE->getInit());
CheckSubElementType(IList, CurrentObjectType, Index,
StructuredList, StructuredIndex);
// Restore the designated initializer expression in the syntactic
// form of the initializer list.
if (IList->getInit(OldIndex) != DIE->getInit())
DIE->setInit(IList->getInit(OldIndex));
IList->setInit(OldIndex, DIE);
return hadError && !prevHadError;
}
bool IsFirstDesignator = (D == DIE->designators_begin());
assert((IsFirstDesignator || StructuredList) &&
"Need a non-designated initializer list to start from");
// Determine the structural initializer list that corresponds to the
// current subobject.
StructuredList = IsFirstDesignator? SyntacticToSemantic[IList]
: getStructuredSubobjectInit(IList, Index, CurrentObjectType, StructuredList,
StructuredIndex,
SourceRange(D->getStartLocation(),
DIE->getSourceRange().getEnd()));
assert(StructuredList && "Expected a structured initializer list");
if (D->isFieldDesignator()) {
// C99 6.7.8p7:
//
// If a designator has the form
//
// . identifier
//
// then the current object (defined below) shall have
// structure or union type and the identifier shall be the
// name of a member of that type.
const RecordType *RT = CurrentObjectType->getAsRecordType();
if (!RT) {
SourceLocation Loc = D->getDotLoc();
if (Loc.isInvalid())
Loc = D->getFieldLoc();
SemaRef->Diag(Loc, diag::err_field_designator_non_aggr)
<< SemaRef->getLangOptions().CPlusPlus << CurrentObjectType;
++Index;
return true;
}
// Note: we perform a linear search of the fields here, despite
// the fact that we have a faster lookup method, because we always
// need to compute the field's index.
IdentifierInfo *FieldName = D->getFieldName();
unsigned FieldIndex = 0;
RecordDecl::field_iterator Field = RT->getDecl()->field_begin(),
FieldEnd = RT->getDecl()->field_end();
for (; Field != FieldEnd; ++Field) {
if (Field->isUnnamedBitfield())
continue;
if (Field->getIdentifier() == FieldName)
break;
++FieldIndex;
}
if (Field == FieldEnd) {
// We did not find the field we're looking for. Produce a
// suitable diagnostic and return a failure.
DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
if (Lookup.first == Lookup.second) {
// Name lookup didn't find anything.
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
<< FieldName << CurrentObjectType;
} else {
// Name lookup found something, but it wasn't a field.
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
<< FieldName;
SemaRef->Diag((*Lookup.first)->getLocation(),
diag::note_field_designator_found);
}
++Index;
return true;
} else if (cast<RecordDecl>((*Field)->getDeclContext())
->isAnonymousStructOrUnion()) {
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_anon_class)
<< FieldName
<< (cast<RecordDecl>((*Field)->getDeclContext())->isUnion()? 2 :
(int)SemaRef->getLangOptions().CPlusPlus);
SemaRef->Diag((*Field)->getLocation(), diag::note_field_designator_found);
++Index;
return true;
}
// All of the fields of a union are located at the same place in
// the initializer list.
if (RT->getDecl()->isUnion()) {
FieldIndex = 0;
StructuredList->setInitializedFieldInUnion(*Field);
}
// Update the designator with the field declaration.
D->setField(*Field);
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this field.
if (FieldIndex >= StructuredList->getNumInits())
StructuredList->resizeInits(SemaRef->Context, FieldIndex + 1);
// Recurse to check later designated subobjects.
QualType FieldType = (*Field)->getType();
unsigned newStructuredIndex = FieldIndex;
if (CheckDesignatedInitializer(IList, DIE, ++D, FieldType, 0, 0, Index,
StructuredList, newStructuredIndex))
return true;
// Find the position of the next field to be initialized in this
// subobject.
++Field;
++FieldIndex;
// If this the first designator, our caller will continue checking
// the rest of this struct/class/union subobject.
if (IsFirstDesignator) {
if (NextField)
*NextField = Field;
StructuredIndex = FieldIndex;
return false;
}
if (!FinishSubobjectInit)
return false;
// Check the remaining fields within this class/struct/union subobject.
bool prevHadError = hadError;
CheckStructUnionTypes(IList, CurrentObjectType, Field, false, Index,
StructuredList, FieldIndex);
return hadError && !prevHadError;
}
// C99 6.7.8p6:
//
// If a designator has the form
//
// [ constant-expression ]
//
// then the current object (defined below) shall have array
// type and the expression shall be an integer constant
// expression. If the array is of unknown size, any
// nonnegative value is valid.
//
// Additionally, cope with the GNU extension that permits
// designators of the form
//
// [ constant-expression ... constant-expression ]
const ArrayType *AT = SemaRef->Context.getAsArrayType(CurrentObjectType);
if (!AT) {
SemaRef->Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
<< CurrentObjectType;
++Index;
return true;
}
Expr *IndexExpr = 0;
llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
if (D->isArrayDesignator()) {
IndexExpr = DIE->getArrayIndex(*D);
bool ConstExpr
= IndexExpr->isIntegerConstantExpr(DesignatedStartIndex, SemaRef->Context);
assert(ConstExpr && "Expression must be constant"); (void)ConstExpr;
DesignatedEndIndex = DesignatedStartIndex;
} else {
assert(D->isArrayRangeDesignator() && "Need array-range designator");
bool StartConstExpr
= DIE->getArrayRangeStart(*D)->isIntegerConstantExpr(DesignatedStartIndex,
SemaRef->Context);
assert(StartConstExpr && "Expression must be constant"); (void)StartConstExpr;
bool EndConstExpr
= DIE->getArrayRangeEnd(*D)->isIntegerConstantExpr(DesignatedEndIndex,
SemaRef->Context);
assert(EndConstExpr && "Expression must be constant"); (void)EndConstExpr;
IndexExpr = DIE->getArrayRangeEnd(*D);
if (DesignatedStartIndex.getZExtValue() != DesignatedEndIndex.getZExtValue())
SemaRef->Diag(D->getEllipsisLoc(),
diag::warn_gnu_array_range_designator_side_effects)
<< SourceRange(D->getLBracketLoc(), D->getRBracketLoc());
}
if (isa<ConstantArrayType>(AT)) {
llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
if (DesignatedEndIndex >= MaxElements) {
SemaRef->Diag(IndexExpr->getSourceRange().getBegin(),
diag::err_array_designator_too_large)
<< DesignatedEndIndex.toString(10) << MaxElements.toString(10)
<< IndexExpr->getSourceRange();
++Index;
return true;
}
} else {
// Make sure the bit-widths and signedness match.
if (DesignatedStartIndex.getBitWidth() > DesignatedEndIndex.getBitWidth())
DesignatedEndIndex.extend(DesignatedStartIndex.getBitWidth());
else if (DesignatedStartIndex.getBitWidth() < DesignatedEndIndex.getBitWidth())
DesignatedStartIndex.extend(DesignatedEndIndex.getBitWidth());
DesignatedStartIndex.setIsUnsigned(true);
DesignatedEndIndex.setIsUnsigned(true);
}
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this array element.
if (DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
StructuredList->resizeInits(SemaRef->Context,
DesignatedEndIndex.getZExtValue() + 1);
// Repeatedly perform subobject initializations in the range
// [DesignatedStartIndex, DesignatedEndIndex].
// Move to the next designator
unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
unsigned OldIndex = Index;
++D;
while (DesignatedStartIndex <= DesignatedEndIndex) {
// Recurse to check later designated subobjects.
QualType ElementType = AT->getElementType();
Index = OldIndex;
if (CheckDesignatedInitializer(IList, DIE, D, ElementType, 0, 0, Index,
StructuredList, ElementIndex,
(DesignatedStartIndex == DesignatedEndIndex)))
return true;
// Move to the next index in the array that we'll be initializing.
++DesignatedStartIndex;
ElementIndex = DesignatedStartIndex.getZExtValue();
}
// If this the first designator, our caller will continue checking
// the rest of this array subobject.
if (IsFirstDesignator) {
if (NextElementIndex)
*NextElementIndex = DesignatedStartIndex;
StructuredIndex = ElementIndex;
return false;
}
if (!FinishSubobjectInit)
return false;
// Check the remaining elements within this array subobject.
bool prevHadError = hadError;
CheckArrayType(IList, CurrentObjectType, DesignatedStartIndex, true, Index,
StructuredList, ElementIndex);
return hadError && !prevHadError;
}
// Get the structured initializer list for a subobject of type
// @p CurrentObjectType.
InitListExpr *
InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
unsigned StructuredIndex,
SourceRange InitRange) {
Expr *ExistingInit = 0;
if (!StructuredList)
ExistingInit = SyntacticToSemantic[IList];
else if (StructuredIndex < StructuredList->getNumInits())
ExistingInit = StructuredList->getInit(StructuredIndex);
if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
return Result;
if (ExistingInit) {
// We are creating an initializer list that initializes the
// subobjects of the current object, but there was already an
// initialization that completely initialized the current
// subobject, e.g., by a compound literal:
//
// struct X { int a, b; };
// struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
//
// Here, xs[0].a == 0 and xs[0].b == 3, since the second,
// designated initializer re-initializes the whole
// subobject [0], overwriting previous initializers.
SemaRef->Diag(InitRange.getBegin(), diag::warn_subobject_initializer_overrides)
<< InitRange;
SemaRef->Diag(ExistingInit->getSourceRange().getBegin(),
diag::note_previous_initializer)
<< /*FIXME:has side effects=*/0
<< ExistingInit->getSourceRange();
}
InitListExpr *Result
= new (SemaRef->Context) InitListExpr(SourceLocation(), 0, 0,
SourceLocation());
Result->setType(CurrentObjectType);
// Link this new initializer list into the structured initializer
// lists.
if (StructuredList)
StructuredList->updateInit(StructuredIndex, Result);
else {
Result->setSyntacticForm(IList);
SyntacticToSemantic[IList] = Result;
}
return Result;
}
/// Update the initializer at index @p StructuredIndex within the
/// structured initializer list to the value @p expr.
void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
unsigned &StructuredIndex,
Expr *expr) {
// No structured initializer list to update
if (!StructuredList)
return;
if (Expr *PrevInit = StructuredList->updateInit(StructuredIndex, expr)) {
// This initializer overwrites a previous initializer. Warn.
SemaRef->Diag(expr->getSourceRange().getBegin(),
diag::warn_initializer_overrides)
<< expr->getSourceRange();
SemaRef->Diag(PrevInit->getSourceRange().getBegin(),
diag::note_previous_initializer)
<< /*FIXME:has side effects=*/0
<< PrevInit->getSourceRange();
}
++StructuredIndex;
}
/// Check that the given Index expression is a valid array designator
/// value. This is essentailly just a wrapper around
/// Expr::isIntegerConstantExpr that also checks for negative values
/// and produces a reasonable diagnostic if there is a
/// failure. Returns true if there was an error, false otherwise. If
/// everything went okay, Value will receive the value of the constant
/// expression.
static bool
CheckArrayDesignatorExpr(Sema &Self, Expr *Index, llvm::APSInt &Value) {
SourceLocation Loc = Index->getSourceRange().getBegin();
// Make sure this is an integer constant expression.
if (!Index->isIntegerConstantExpr(Value, Self.Context, &Loc))
return Self.Diag(Loc, diag::err_array_designator_nonconstant)
<< Index->getSourceRange();
// Make sure this constant expression is non-negative.
llvm::APSInt Zero(llvm::APSInt::getNullValue(Value.getBitWidth()),
Value.isUnsigned());
if (Value < Zero)
return Self.Diag(Loc, diag::err_array_designator_negative)
<< Value.toString(10) << Index->getSourceRange();
Value.setIsUnsigned(true);
return false;
}
Sema::OwningExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
SourceLocation Loc,
bool UsedColonSyntax,
OwningExprResult Init) {
typedef DesignatedInitExpr::Designator ASTDesignator;
bool Invalid = false;
llvm::SmallVector<ASTDesignator, 32> Designators;
llvm::SmallVector<Expr *, 32> InitExpressions;
// Build designators and check array designator expressions.
for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
const Designator &D = Desig.getDesignator(Idx);
switch (D.getKind()) {
case Designator::FieldDesignator:
Designators.push_back(ASTDesignator(D.getField(), D.getDotLoc(),
D.getFieldLoc()));
break;
case Designator::ArrayDesignator: {
Expr *Index = static_cast<Expr *>(D.getArrayIndex());
llvm::APSInt IndexValue;
if (CheckArrayDesignatorExpr(*this, Index, IndexValue))
Invalid = true;
else {
Designators.push_back(ASTDesignator(InitExpressions.size(),
D.getLBracketLoc(),
D.getRBracketLoc()));
InitExpressions.push_back(Index);
}
break;
}
case Designator::ArrayRangeDesignator: {
Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
llvm::APSInt StartValue;
llvm::APSInt EndValue;
if (CheckArrayDesignatorExpr(*this, StartIndex, StartValue) ||
CheckArrayDesignatorExpr(*this, EndIndex, EndValue))
Invalid = true;
else {
// Make sure we're comparing values with the same bit width.
if (StartValue.getBitWidth() > EndValue.getBitWidth())
EndValue.extend(StartValue.getBitWidth());
else if (StartValue.getBitWidth() < EndValue.getBitWidth())
StartValue.extend(EndValue.getBitWidth());
if (EndValue < StartValue) {
Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
<< StartValue.toString(10) << EndValue.toString(10)
<< StartIndex->getSourceRange() << EndIndex->getSourceRange();
Invalid = true;
} else {
Designators.push_back(ASTDesignator(InitExpressions.size(),
D.getLBracketLoc(),
D.getEllipsisLoc(),
D.getRBracketLoc()));
InitExpressions.push_back(StartIndex);
InitExpressions.push_back(EndIndex);
}
}
break;
}
}
}
if (Invalid || Init.isInvalid())
return ExprError();
// Clear out the expressions within the designation.
Desig.ClearExprs(*this);
DesignatedInitExpr *DIE
= DesignatedInitExpr::Create(Context, &Designators[0], Designators.size(),
&InitExpressions[0], InitExpressions.size(),
Loc, UsedColonSyntax,
static_cast<Expr *>(Init.release()));
return Owned(DIE);
}
bool Sema::CheckInitList(InitListExpr *&InitList, QualType &DeclType) {
InitListChecker CheckInitList(this, InitList, DeclType);
if (!CheckInitList.HadError())
InitList = CheckInitList.getFullyStructuredList();
return CheckInitList.HadError();
}
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