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//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
//
// 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 statements.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/StmtObjC.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetAsmParser.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
using namespace clang;
using namespace sema;
StmtResult Sema::ActOnExprStmt(FullExprArg expr) {
Expr *E = expr.get();
if (!E) // FIXME: FullExprArg has no error state?
return StmtError();
// C99 6.8.3p2: The expression in an expression statement is evaluated as a
// void expression for its side effects. Conversion to void allows any
// operand, even incomplete types.
// Same thing in for stmt first clause (when expr) and third clause.
return Owned(static_cast<Stmt*>(E));
}
StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
bool HasLeadingEmptyMacro) {
return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro));
}
StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
SourceLocation EndLoc) {
DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
// If we have an invalid decl, just return an error.
if (DG.isNull()) return StmtError();
return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc));
}
void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
// If we have an invalid decl, just return.
if (DG.isNull() || !DG.isSingleDecl()) return;
VarDecl *var = cast<VarDecl>(DG.getSingleDecl());
// suppress any potential 'unused variable' warning.
var->setUsed();
// foreach variables are never actually initialized in the way that
// the parser came up with.
var->setInit(0);
// In ARC, we don't need to retain the iteration variable of a fast
// enumeration loop. Rather than actually trying to catch that
// during declaration processing, we remove the consequences here.
if (getLangOpts().ObjCAutoRefCount) {
QualType type = var->getType();
// Only do this if we inferred the lifetime. Inferred lifetime
// will show up as a local qualifier because explicit lifetime
// should have shown up as an AttributedType instead.
if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
// Add 'const' and mark the variable as pseudo-strong.
var->setType(type.withConst());
var->setARCPseudoStrong(true);
}
}
}
/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='.
///
/// Adding a cast to void (or other expression wrappers) will prevent the
/// warning from firing.
static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
SourceLocation Loc;
bool IsNotEqual, CanAssign;
if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE)
return false;
Loc = Op->getOperatorLoc();
IsNotEqual = Op->getOpcode() == BO_NE;
CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
} else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
if (Op->getOperator() != OO_EqualEqual &&
Op->getOperator() != OO_ExclaimEqual)
return false;
Loc = Op->getOperatorLoc();
IsNotEqual = Op->getOperator() == OO_ExclaimEqual;
CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
} else {
// Not a typo-prone comparison.
return false;
}
// Suppress warnings when the operator, suspicious as it may be, comes from
// a macro expansion.
if (Loc.isMacroID())
return false;
S.Diag(Loc, diag::warn_unused_comparison)
<< (unsigned)IsNotEqual << E->getSourceRange();
// If the LHS is a plausible entity to assign to, provide a fixit hint to
// correct common typos.
if (CanAssign) {
if (IsNotEqual)
S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
<< FixItHint::CreateReplacement(Loc, "|=");
else
S.Diag(Loc, diag::note_equality_comparison_to_assign)
<< FixItHint::CreateReplacement(Loc, "=");
}
return true;
}
void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
return DiagnoseUnusedExprResult(Label->getSubStmt());
const Expr *E = dyn_cast_or_null<Expr>(S);
if (!E)
return;
const Expr *WarnExpr;
SourceLocation Loc;
SourceRange R1, R2;
if (SourceMgr.isInSystemMacro(E->getExprLoc()) ||
!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
return;
// Okay, we have an unused result. Depending on what the base expression is,
// we might want to make a more specific diagnostic. Check for one of these
// cases now.
unsigned DiagID = diag::warn_unused_expr;
if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
E = Temps->getSubExpr();
if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
E = TempExpr->getSubExpr();
if (DiagnoseUnusedComparison(*this, E))
return;
E = WarnExpr;
if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
if (E->getType()->isVoidType())
return;
// If the callee has attribute pure, const, or warn_unused_result, warn with
// a more specific message to make it clear what is happening.
if (const Decl *FD = CE->getCalleeDecl()) {
if (FD->getAttr<WarnUnusedResultAttr>()) {
Diag(Loc, diag::warn_unused_result) << R1 << R2;
return;
}
if (FD->getAttr<PureAttr>()) {
Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
return;
}
if (FD->getAttr<ConstAttr>()) {
Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
return;
}
}
} else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
Diag(Loc, diag::err_arc_unused_init_message) << R1;
return;
}
const ObjCMethodDecl *MD = ME->getMethodDecl();
if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
Diag(Loc, diag::warn_unused_result) << R1 << R2;
return;
}
} else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
const Expr *Source = POE->getSyntacticForm();
if (isa<ObjCSubscriptRefExpr>(Source))
DiagID = diag::warn_unused_container_subscript_expr;
else
DiagID = diag::warn_unused_property_expr;
} else if (const CXXFunctionalCastExpr *FC
= dyn_cast<CXXFunctionalCastExpr>(E)) {
if (isa<CXXConstructExpr>(FC->getSubExpr()) ||
isa<CXXTemporaryObjectExpr>(FC->getSubExpr()))
return;
}
// Diagnose "(void*) blah" as a typo for "(void) blah".
else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
QualType T = TI->getType();
// We really do want to use the non-canonical type here.
if (T == Context.VoidPtrTy) {
PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc());
Diag(Loc, diag::warn_unused_voidptr)
<< FixItHint::CreateRemoval(TL.getStarLoc());
return;
}
}
if (E->isGLValue() && E->getType().isVolatileQualified()) {
Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
return;
}
DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2);
}
void Sema::ActOnStartOfCompoundStmt() {
PushCompoundScope();
}
void Sema::ActOnFinishOfCompoundStmt() {
PopCompoundScope();
}
sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
return getCurFunction()->CompoundScopes.back();
}
StmtResult
Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
MultiStmtArg elts, bool isStmtExpr) {
unsigned NumElts = elts.size();
Stmt **Elts = reinterpret_cast<Stmt**>(elts.release());
// If we're in C89 mode, check that we don't have any decls after stmts. If
// so, emit an extension diagnostic.
if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
// Note that __extension__ can be around a decl.
unsigned i = 0;
// Skip over all declarations.
for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
/*empty*/;
// We found the end of the list or a statement. Scan for another declstmt.
for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
/*empty*/;
if (i != NumElts) {
Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
Diag(D->getLocation(), diag::ext_mixed_decls_code);
}
}
// Warn about unused expressions in statements.
for (unsigned i = 0; i != NumElts; ++i) {
// Ignore statements that are last in a statement expression.
if (isStmtExpr && i == NumElts - 1)
continue;
DiagnoseUnusedExprResult(Elts[i]);
}
// Check for suspicious empty body (null statement) in `for' and `while'
// statements. Don't do anything for template instantiations, this just adds
// noise.
if (NumElts != 0 && !CurrentInstantiationScope &&
getCurCompoundScope().HasEmptyLoopBodies) {
for (unsigned i = 0; i != NumElts - 1; ++i)
DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
}
return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R));
}
StmtResult
Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
SourceLocation DotDotDotLoc, Expr *RHSVal,
SourceLocation ColonLoc) {
assert((LHSVal != 0) && "missing expression in case statement");
if (getCurFunction()->SwitchStack.empty()) {
Diag(CaseLoc, diag::err_case_not_in_switch);
return StmtError();
}
if (!getLangOpts().CPlusPlus0x) {
// C99 6.8.4.2p3: The expression shall be an integer constant.
// However, GCC allows any evaluatable integer expression.
if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) {
LHSVal = VerifyIntegerConstantExpression(LHSVal).take();
if (!LHSVal)
return StmtError();
}
// GCC extension: The expression shall be an integer constant.
if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) {
RHSVal = VerifyIntegerConstantExpression(RHSVal).take();
// Recover from an error by just forgetting about it.
}
}
CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc,
ColonLoc);
getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
return Owned(CS);
}
/// ActOnCaseStmtBody - This installs a statement as the body of a case.
void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
DiagnoseUnusedExprResult(SubStmt);
CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
CS->setSubStmt(SubStmt);
}
StmtResult
Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
Stmt *SubStmt, Scope *CurScope) {
DiagnoseUnusedExprResult(SubStmt);
if (getCurFunction()->SwitchStack.empty()) {
Diag(DefaultLoc, diag::err_default_not_in_switch);
return Owned(SubStmt);
}
DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
return Owned(DS);
}
StmtResult
Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
SourceLocation ColonLoc, Stmt *SubStmt) {
// If the label was multiply defined, reject it now.
if (TheDecl->getStmt()) {
Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
Diag(TheDecl->getLocation(), diag::note_previous_definition);
return Owned(SubStmt);
}
// Otherwise, things are good. Fill in the declaration and return it.
LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
TheDecl->setStmt(LS);
if (!TheDecl->isGnuLocal())
TheDecl->setLocation(IdentLoc);
return Owned(LS);
}
StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
ArrayRef<const Attr*> Attrs,
Stmt *SubStmt) {
// Fill in the declaration and return it.
AttributedStmt *LS = AttributedStmt::Create(Context, AttrLoc, Attrs, SubStmt);
return Owned(LS);
}
StmtResult
Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
Stmt *thenStmt, SourceLocation ElseLoc,
Stmt *elseStmt) {
ExprResult CondResult(CondVal.release());
VarDecl *ConditionVar = 0;
if (CondVar) {
ConditionVar = cast<VarDecl>(CondVar);
CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
if (CondResult.isInvalid())
return StmtError();
}
Expr *ConditionExpr = CondResult.takeAs<Expr>();
if (!ConditionExpr)
return StmtError();
DiagnoseUnusedExprResult(thenStmt);
if (!elseStmt) {
DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
diag::warn_empty_if_body);
}
DiagnoseUnusedExprResult(elseStmt);
return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
thenStmt, ElseLoc, elseStmt));
}
/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
/// the specified width and sign. If an overflow occurs, detect it and emit
/// the specified diagnostic.
void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
unsigned NewWidth, bool NewSign,
SourceLocation Loc,
unsigned DiagID) {
// Perform a conversion to the promoted condition type if needed.
if (NewWidth > Val.getBitWidth()) {
// If this is an extension, just do it.
Val = Val.extend(NewWidth);
Val.setIsSigned(NewSign);
// If the input was signed and negative and the output is
// unsigned, don't bother to warn: this is implementation-defined
// behavior.
// FIXME: Introduce a second, default-ignored warning for this case?
} else if (NewWidth < Val.getBitWidth()) {
// If this is a truncation, check for overflow.
llvm::APSInt ConvVal(Val);
ConvVal = ConvVal.trunc(NewWidth);
ConvVal.setIsSigned(NewSign);
ConvVal = ConvVal.extend(Val.getBitWidth());
ConvVal.setIsSigned(Val.isSigned());
if (ConvVal != Val)
Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10);
// Regardless of whether a diagnostic was emitted, really do the
// truncation.
Val = Val.trunc(NewWidth);
Val.setIsSigned(NewSign);
} else if (NewSign != Val.isSigned()) {
// Convert the sign to match the sign of the condition. This can cause
// overflow as well: unsigned(INTMIN)
// We don't diagnose this overflow, because it is implementation-defined
// behavior.
// FIXME: Introduce a second, default-ignored warning for this case?
llvm::APSInt OldVal(Val);
Val.setIsSigned(NewSign);
}
}
namespace {
struct CaseCompareFunctor {
bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
const llvm::APSInt &RHS) {
return LHS.first < RHS;
}
bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
return LHS.first < RHS.first;
}
bool operator()(const llvm::APSInt &LHS,
const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
return LHS < RHS.first;
}
};
}
/// CmpCaseVals - Comparison predicate for sorting case values.
///
static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
if (lhs.first < rhs.first)
return true;
if (lhs.first == rhs.first &&
lhs.second->getCaseLoc().getRawEncoding()
< rhs.second->getCaseLoc().getRawEncoding())
return true;
return false;
}
/// CmpEnumVals - Comparison predicate for sorting enumeration values.
///
static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
{
return lhs.first < rhs.first;
}
/// EqEnumVals - Comparison preficate for uniqing enumeration values.
///
static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
{
return lhs.first == rhs.first;
}
/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
/// potentially integral-promoted expression @p expr.
static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr))
expr = cleanups->getSubExpr();
while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) {
if (impcast->getCastKind() != CK_IntegralCast) break;
expr = impcast->getSubExpr();
}
return expr->getType();
}
StmtResult
Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
Decl *CondVar) {
ExprResult CondResult;
VarDecl *ConditionVar = 0;
if (CondVar) {
ConditionVar = cast<VarDecl>(CondVar);
CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
if (CondResult.isInvalid())
return StmtError();
Cond = CondResult.release();
}
if (!Cond)
return StmtError();
class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
Expr *Cond;
public:
SwitchConvertDiagnoser(Expr *Cond)
: ICEConvertDiagnoser(false, true), Cond(Cond) { }
virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
QualType T) {
return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
}
virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
QualType T) {
return S.Diag(Loc, diag::err_switch_incomplete_class_type)
<< T << Cond->getSourceRange();
}
virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
QualType T,
QualType ConvTy) {
return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
}
virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv,
QualType ConvTy) {
return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
<< ConvTy->isEnumeralType() << ConvTy;
}
virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
QualType T) {
return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
}
virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
QualType ConvTy) {
return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
<< ConvTy->isEnumeralType() << ConvTy;
}
virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
QualType T,
QualType ConvTy) {
return DiagnosticBuilder::getEmpty();
}
} SwitchDiagnoser(Cond);
CondResult
= ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser,
/*AllowScopedEnumerations*/ true);
if (CondResult.isInvalid()) return StmtError();
Cond = CondResult.take();
// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
CondResult = UsualUnaryConversions(Cond);
if (CondResult.isInvalid()) return StmtError();
Cond = CondResult.take();
if (!CondVar) {
CheckImplicitConversions(Cond, SwitchLoc);
CondResult = MaybeCreateExprWithCleanups(Cond);
if (CondResult.isInvalid())
return StmtError();
Cond = CondResult.take();
}
getCurFunction()->setHasBranchIntoScope();
SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
getCurFunction()->SwitchStack.push_back(SS);
return Owned(SS);
}
static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
if (Val.getBitWidth() < BitWidth)
Val = Val.extend(BitWidth);
else if (Val.getBitWidth() > BitWidth)
Val = Val.trunc(BitWidth);
Val.setIsSigned(IsSigned);
}
StmtResult
Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
Stmt *BodyStmt) {
SwitchStmt *SS = cast<SwitchStmt>(Switch);
assert(SS == getCurFunction()->SwitchStack.back() &&
"switch stack missing push/pop!");
SS->setBody(BodyStmt, SwitchLoc);
getCurFunction()->SwitchStack.pop_back();
Expr *CondExpr = SS->getCond();
if (!CondExpr) return StmtError();
QualType CondType = CondExpr->getType();
Expr *CondExprBeforePromotion = CondExpr;
QualType CondTypeBeforePromotion =
GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
// C++ 6.4.2.p2:
// Integral promotions are performed (on the switch condition).
//
// A case value unrepresentable by the original switch condition
// type (before the promotion) doesn't make sense, even when it can
// be represented by the promoted type. Therefore we need to find
// the pre-promotion type of the switch condition.
if (!CondExpr->isTypeDependent()) {
// We have already converted the expression to an integral or enumeration
// type, when we started the switch statement. If we don't have an
// appropriate type now, just return an error.
if (!CondType->isIntegralOrEnumerationType())
return StmtError();
if (CondExpr->isKnownToHaveBooleanValue()) {
// switch(bool_expr) {...} is often a programmer error, e.g.
// switch(n && mask) { ... } // Doh - should be "n & mask".
// One can always use an if statement instead of switch(bool_expr).
Diag(SwitchLoc, diag::warn_bool_switch_condition)
<< CondExpr->getSourceRange();
}
}
// Get the bitwidth of the switched-on value before promotions. We must
// convert the integer case values to this width before comparison.
bool HasDependentValue
= CondExpr->isTypeDependent() || CondExpr->isValueDependent();
unsigned CondWidth
= HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
bool CondIsSigned
= CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
// Accumulate all of the case values in a vector so that we can sort them
// and detect duplicates. This vector contains the APInt for the case after
// it has been converted to the condition type.
typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
CaseValsTy CaseVals;
// Keep track of any GNU case ranges we see. The APSInt is the low value.
typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
CaseRangesTy CaseRanges;
DefaultStmt *TheDefaultStmt = 0;
bool CaseListIsErroneous = false;
for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
SC = SC->getNextSwitchCase()) {
if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
if (TheDefaultStmt) {
Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
// FIXME: Remove the default statement from the switch block so that
// we'll return a valid AST. This requires recursing down the AST and
// finding it, not something we are set up to do right now. For now,
// just lop the entire switch stmt out of the AST.
CaseListIsErroneous = true;
}
TheDefaultStmt = DS;
} else {
CaseStmt *CS = cast<CaseStmt>(SC);
Expr *Lo = CS->getLHS();
if (Lo->isTypeDependent() || Lo->isValueDependent()) {
HasDependentValue = true;
break;
}
llvm::APSInt LoVal;
if (getLangOpts().CPlusPlus0x) {
// C++11 [stmt.switch]p2: the constant-expression shall be a converted
// constant expression of the promoted type of the switch condition.
ExprResult ConvLo =
CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue);
if (ConvLo.isInvalid()) {
CaseListIsErroneous = true;
continue;
}
Lo = ConvLo.take();
} else {
// We already verified that the expression has a i-c-e value (C99
// 6.8.4.2p3) - get that value now.
LoVal = Lo->EvaluateKnownConstInt(Context);
// If the LHS is not the same type as the condition, insert an implicit
// cast.
Lo = DefaultLvalueConversion(Lo).take();
Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take();
}
// Convert the value to the same width/sign as the condition had prior to
// integral promotions.
//
// FIXME: This causes us to reject valid code:
// switch ((char)c) { case 256: case 0: return 0; }
// Here we claim there is a duplicated condition value, but there is not.
ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
Lo->getLocStart(),
diag::warn_case_value_overflow);
CS->setLHS(Lo);
// If this is a case range, remember it in CaseRanges, otherwise CaseVals.
if (CS->getRHS()) {
if (CS->getRHS()->isTypeDependent() ||
CS->getRHS()->isValueDependent()) {
HasDependentValue = true;
break;
}
CaseRanges.push_back(std::make_pair(LoVal, CS));
} else
CaseVals.push_back(std::make_pair(LoVal, CS));
}
}
if (!HasDependentValue) {
// If we don't have a default statement, check whether the
// condition is constant.
llvm::APSInt ConstantCondValue;
bool HasConstantCond = false;
if (!HasDependentValue && !TheDefaultStmt) {
HasConstantCond
= CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context,
Expr::SE_AllowSideEffects);
assert(!HasConstantCond ||
(ConstantCondValue.getBitWidth() == CondWidth &&
ConstantCondValue.isSigned() == CondIsSigned));
}
bool ShouldCheckConstantCond = HasConstantCond;
// Sort all the scalar case values so we can easily detect duplicates.
std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
if (!CaseVals.empty()) {
for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
if (ShouldCheckConstantCond &&
CaseVals[i].first == ConstantCondValue)
ShouldCheckConstantCond = false;
if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
// If we have a duplicate, report it.
// First, determine if either case value has a name
StringRef PrevString, CurrString;
Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
PrevString = DeclRef->getDecl()->getName();
}
if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
CurrString = DeclRef->getDecl()->getName();
}
llvm::SmallString<16> CaseValStr;
CaseVals[i-1].first.toString(CaseValStr);
if (PrevString == CurrString)
Diag(CaseVals[i].second->getLHS()->getLocStart(),
diag::err_duplicate_case) <<
(PrevString.empty() ? CaseValStr.str() : PrevString);
else
Diag(CaseVals[i].second->getLHS()->getLocStart(),
diag::err_duplicate_case_differing_expr) <<
(PrevString.empty() ? CaseValStr.str() : PrevString) <<
(CurrString.empty() ? CaseValStr.str() : CurrString) <<
CaseValStr;
Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
diag::note_duplicate_case_prev);
// FIXME: We really want to remove the bogus case stmt from the
// substmt, but we have no way to do this right now.
CaseListIsErroneous = true;
}
}
}
// Detect duplicate case ranges, which usually don't exist at all in
// the first place.
if (!CaseRanges.empty()) {
// Sort all the case ranges by their low value so we can easily detect
// overlaps between ranges.
std::stable_sort(CaseRanges.begin(), CaseRanges.end());
// Scan the ranges, computing the high values and removing empty ranges.
std::vector<llvm::APSInt> HiVals;
for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
llvm::APSInt &LoVal = CaseRanges[i].first;
CaseStmt *CR = CaseRanges[i].second;
Expr *Hi = CR->getRHS();
llvm::APSInt HiVal;
if (getLangOpts().CPlusPlus0x) {
// C++11 [stmt.switch]p2: the constant-expression shall be a converted
// constant expression of the promoted type of the switch condition.
ExprResult ConvHi =
CheckConvertedConstantExpression(Hi, CondType, HiVal,
CCEK_CaseValue);
if (ConvHi.isInvalid()) {
CaseListIsErroneous = true;
continue;
}
Hi = ConvHi.take();
} else {
HiVal = Hi->EvaluateKnownConstInt(Context);
// If the RHS is not the same type as the condition, insert an
// implicit cast.
Hi = DefaultLvalueConversion(Hi).take();
Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take();
}
// Convert the value to the same width/sign as the condition.
ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
Hi->getLocStart(),
diag::warn_case_value_overflow);
CR->setRHS(Hi);
// If the low value is bigger than the high value, the case is empty.
if (LoVal > HiVal) {
Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
<< SourceRange(CR->getLHS()->getLocStart(),
Hi->getLocEnd());
CaseRanges.erase(CaseRanges.begin()+i);
--i, --e;
continue;
}
if (ShouldCheckConstantCond &&
LoVal <= ConstantCondValue &&
ConstantCondValue <= HiVal)
ShouldCheckConstantCond = false;
HiVals.push_back(HiVal);
}
// Rescan the ranges, looking for overlap with singleton values and other
// ranges. Since the range list is sorted, we only need to compare case
// ranges with their neighbors.
for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
llvm::APSInt &CRLo = CaseRanges[i].first;
llvm::APSInt &CRHi = HiVals[i];
CaseStmt *CR = CaseRanges[i].second;
// Check to see whether the case range overlaps with any
// singleton cases.
CaseStmt *OverlapStmt = 0;
llvm::APSInt OverlapVal(32);
// Find the smallest value >= the lower bound. If I is in the
// case range, then we have overlap.
CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
CaseVals.end(), CRLo,
CaseCompareFunctor());
if (I != CaseVals.end() && I->first < CRHi) {
OverlapVal = I->first; // Found overlap with scalar.
OverlapStmt = I->second;
}
// Find the smallest value bigger than the upper bound.
I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
OverlapVal = (I-1)->first; // Found overlap with scalar.
OverlapStmt = (I-1)->second;
}
// Check to see if this case stmt overlaps with the subsequent
// case range.
if (i && CRLo <= HiVals[i-1]) {
OverlapVal = HiVals[i-1]; // Found overlap with range.
OverlapStmt = CaseRanges[i-1].second;
}
if (OverlapStmt) {
// If we have a duplicate, report it.
Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
<< OverlapVal.toString(10);
Diag(OverlapStmt->getLHS()->getLocStart(),
diag::note_duplicate_case_prev);
// FIXME: We really want to remove the bogus case stmt from the
// substmt, but we have no way to do this right now.
CaseListIsErroneous = true;
}
}
}
// Complain if we have a constant condition and we didn't find a match.
if (!CaseListIsErroneous && ShouldCheckConstantCond) {
// TODO: it would be nice if we printed enums as enums, chars as
// chars, etc.
Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
<< ConstantCondValue.toString(10)
<< CondExpr->getSourceRange();
}
// Check to see if switch is over an Enum and handles all of its
// values. We only issue a warning if there is not 'default:', but
// we still do the analysis to preserve this information in the AST
// (which can be used by flow-based analyes).
//
const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
// If switch has default case, then ignore it.
if (!CaseListIsErroneous && !HasConstantCond && ET) {
const EnumDecl *ED = ET->getDecl();
typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64>
EnumValsTy;
EnumValsTy EnumVals;
// Gather all enum values, set their type and sort them,
// allowing easier comparison with CaseVals.
for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin();
EDI != ED->enumerator_end(); ++EDI) {
llvm::APSInt Val = EDI->getInitVal();
AdjustAPSInt(Val, CondWidth, CondIsSigned);
EnumVals.push_back(std::make_pair(Val, *EDI));
}
std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
EnumValsTy::iterator EIend =
std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
// See which case values aren't in enum.
EnumValsTy::const_iterator EI = EnumVals.begin();
for (CaseValsTy::const_iterator CI = CaseVals.begin();
CI != CaseVals.end(); CI++) {
while (EI != EIend && EI->first < CI->first)
EI++;
if (EI == EIend || EI->first > CI->first)
Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
<< CondTypeBeforePromotion;
}
// See which of case ranges aren't in enum
EI = EnumVals.begin();
for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
RI != CaseRanges.end() && EI != EIend; RI++) {
while (EI != EIend && EI->first < RI->first)
EI++;
if (EI == EIend || EI->first != RI->first) {
Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
<< CondTypeBeforePromotion;
}
llvm::APSInt Hi =
RI->second->getRHS()->EvaluateKnownConstInt(Context);
AdjustAPSInt(Hi, CondWidth, CondIsSigned);
while (EI != EIend && EI->first < Hi)
EI++;
if (EI == EIend || EI->first != Hi)
Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum)
<< CondTypeBeforePromotion;
}
// Check which enum vals aren't in switch
CaseValsTy::const_iterator CI = CaseVals.begin();
CaseRangesTy::const_iterator RI = CaseRanges.begin();
bool hasCasesNotInSwitch = false;
SmallVector<DeclarationName,8> UnhandledNames;
for (EI = EnumVals.begin(); EI != EIend; EI++){
// Drop unneeded case values
llvm::APSInt CIVal;
while (CI != CaseVals.end() && CI->first < EI->first)
CI++;
if (CI != CaseVals.end() && CI->first == EI->first)
continue;
// Drop unneeded case ranges
for (; RI != CaseRanges.end(); RI++) {
llvm::APSInt Hi =
RI->second->getRHS()->EvaluateKnownConstInt(Context);
AdjustAPSInt(Hi, CondWidth, CondIsSigned);
if (EI->first <= Hi)
break;
}
if (RI == CaseRanges.end() || EI->first < RI->first) {
hasCasesNotInSwitch = true;
UnhandledNames.push_back(EI->second->getDeclName());
}
}
if (TheDefaultStmt && UnhandledNames.empty())
Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
// Produce a nice diagnostic if multiple values aren't handled.
switch (UnhandledNames.size()) {
case 0: break;
case 1:
Diag(CondExpr->getExprLoc(), TheDefaultStmt
? diag::warn_def_missing_case1 : diag::warn_missing_case1)
<< UnhandledNames[0];
break;
case 2:
Diag(CondExpr->getExprLoc(), TheDefaultStmt
? diag::warn_def_missing_case2 : diag::warn_missing_case2)
<< UnhandledNames[0] << UnhandledNames[1];
break;
case 3:
Diag(CondExpr->getExprLoc(), TheDefaultStmt
? diag::warn_def_missing_case3 : diag::warn_missing_case3)
<< UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
break;
default:
Diag(CondExpr->getExprLoc(), TheDefaultStmt
? diag::warn_def_missing_cases : diag::warn_missing_cases)
<< (unsigned)UnhandledNames.size()
<< UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
break;
}
if (!hasCasesNotInSwitch)
SS->setAllEnumCasesCovered();
}
}
DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt,
diag::warn_empty_switch_body);
// FIXME: If the case list was broken is some way, we don't have a good system
// to patch it up. Instead, just return the whole substmt as broken.
if (CaseListIsErroneous)
return StmtError();
return Owned(SS);
}
void
Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
Expr *SrcExpr) {
unsigned DIAG = diag::warn_not_in_enum_assignement;
if (Diags.getDiagnosticLevel(DIAG, SrcExpr->getExprLoc())
== DiagnosticsEngine::Ignored)
return;
if (const EnumType *ET = DstType->getAs<EnumType>())
if (!Context.hasSameType(SrcType, DstType) &&
SrcType->isIntegerType()) {
if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
SrcExpr->isIntegerConstantExpr(Context)) {
// Get the bitwidth of the enum value before promotions.
unsigned DstWith = Context.getIntWidth(DstType);
bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
const EnumDecl *ED = ET->getDecl();
typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64>
EnumValsTy;
EnumValsTy EnumVals;
// Gather all enum values, set their type and sort them,
// allowing easier comparison with rhs constant.
for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin();
EDI != ED->enumerator_end(); ++EDI) {
llvm::APSInt Val = EDI->getInitVal();
AdjustAPSInt(Val, DstWith, DstIsSigned);
EnumVals.push_back(std::make_pair(Val, *EDI));
}
if (EnumVals.empty())
return;
std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
EnumValsTy::iterator EIend =
std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
// See which case values aren't in enum.
EnumValsTy::const_iterator EI = EnumVals.begin();
while (EI != EIend && EI->first < RhsVal)
EI++;
if (EI == EIend || EI->first != RhsVal) {
Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignement)
<< DstType;
}
}
}
}
StmtResult
Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
Decl *CondVar, Stmt *Body) {
ExprResult CondResult(Cond.release());
VarDecl *ConditionVar = 0;
if (CondVar) {
ConditionVar = cast<VarDecl>(CondVar);
CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
if (CondResult.isInvalid())
return StmtError();
}
Expr *ConditionExpr = CondResult.take();
if (!ConditionExpr)
return StmtError();
DiagnoseUnusedExprResult(Body);
if (isa<NullStmt>(Body))
getCurCompoundScope().setHasEmptyLoopBodies();
return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr,
Body, WhileLoc));
}
StmtResult
Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
SourceLocation WhileLoc, SourceLocation CondLParen,
Expr *Cond, SourceLocation CondRParen) {
assert(Cond && "ActOnDoStmt(): missing expression");
ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
if (CondResult.isInvalid() || CondResult.isInvalid())
return StmtError();
Cond = CondResult.take();
CheckImplicitConversions(Cond, DoLoc);
CondResult = MaybeCreateExprWithCleanups(Cond);
if (CondResult.isInvalid())
return StmtError();
Cond = CondResult.take();
DiagnoseUnusedExprResult(Body);
return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen));
}
namespace {
// This visitor will traverse a conditional statement and store all
// the evaluated decls into a vector. Simple is set to true if none
// of the excluded constructs are used.
class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
llvm::SmallPtrSet<VarDecl*, 8> &Decls;
llvm::SmallVector<SourceRange, 10> &Ranges;
bool Simple;
public:
typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls,
llvm::SmallVector<SourceRange, 10> &Ranges) :
Inherited(S.Context),
Decls(Decls),
Ranges(Ranges),
Simple(true) {}
bool isSimple() { return Simple; }
// Replaces the method in EvaluatedExprVisitor.
void VisitMemberExpr(MemberExpr* E) {
Simple = false;
}
// Any Stmt not whitelisted will cause the condition to be marked complex.
void VisitStmt(Stmt *S) {
Simple = false;
}
void VisitBinaryOperator(BinaryOperator *E) {
Visit(E->getLHS());
Visit(E->getRHS());
}
void VisitCastExpr(CastExpr *E) {
Visit(E->getSubExpr());
}
void VisitUnaryOperator(UnaryOperator *E) {
// Skip checking conditionals with derefernces.
if (E->getOpcode() == UO_Deref)
Simple = false;
else
Visit(E->getSubExpr());
}
void VisitConditionalOperator(ConditionalOperator *E) {
Visit(E->getCond());
Visit(E->getTrueExpr());
Visit(E->getFalseExpr());
}
void VisitParenExpr(ParenExpr *E) {
Visit(E->getSubExpr());
}
void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
Visit(E->getOpaqueValue()->getSourceExpr());
Visit(E->getFalseExpr());
}
void VisitIntegerLiteral(IntegerLiteral *E) { }
void VisitFloatingLiteral(FloatingLiteral *E) { }
void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
void VisitCharacterLiteral(CharacterLiteral *E) { }
void VisitGNUNullExpr(GNUNullExpr *E) { }
void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
void VisitDeclRefExpr(DeclRefExpr *E) {
VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
if (!VD) return;
Ranges.push_back(E->getSourceRange());
Decls.insert(VD);
}
}; // end class DeclExtractor
// DeclMatcher checks to see if the decls are used in a non-evauluated
// context.
class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
llvm::SmallPtrSet<VarDecl*, 8> &Decls;
bool FoundDecl;
public:
typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) :
Inherited(S.Context), Decls(Decls), FoundDecl(false) {
if (!Statement) return;
Visit(Statement);
}
void VisitReturnStmt(ReturnStmt *S) {
FoundDecl = true;
}
void VisitBreakStmt(BreakStmt *S) {
FoundDecl = true;
}
void VisitGotoStmt(GotoStmt *S) {
FoundDecl = true;
}
void VisitCastExpr(CastExpr *E) {
if (E->getCastKind() == CK_LValueToRValue)
CheckLValueToRValueCast(E->getSubExpr());
else
Visit(E->getSubExpr());
}
void CheckLValueToRValueCast(Expr *E) {
E = E->IgnoreParenImpCasts();
if (isa<DeclRefExpr>(E)) {
return;
}
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
Visit(CO->getCond());
CheckLValueToRValueCast(CO->getTrueExpr());
CheckLValueToRValueCast(CO->getFalseExpr());
return;
}
if (BinaryConditionalOperator *BCO =
dyn_cast<BinaryConditionalOperator>(E)) {
CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
CheckLValueToRValueCast(BCO->getFalseExpr());
return;
}
Visit(E);
}
void VisitDeclRefExpr(DeclRefExpr *E) {
if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
if (Decls.count(VD))
FoundDecl = true;
}
bool FoundDeclInUse() { return FoundDecl; }
}; // end class DeclMatcher
void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
Expr *Third, Stmt *Body) {
// Condition is empty
if (!Second) return;
if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body,
Second->getLocStart())
== DiagnosticsEngine::Ignored)
return;
PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
llvm::SmallPtrSet<VarDecl*, 8> Decls;
llvm::SmallVector<SourceRange, 10> Ranges;
DeclExtractor DE(S, Decls, Ranges);
DE.Visit(Second);
// Don't analyze complex conditionals.
if (!DE.isSimple()) return;
// No decls found.
if (Decls.size() == 0) return;
// Don't warn on volatile, static, or global variables.
for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(),
E = Decls.end();
I != E; ++I)
if ((*I)->getType().isVolatileQualified() ||
(*I)->hasGlobalStorage()) return;
if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
DeclMatcher(S, Decls, Body).FoundDeclInUse())
return;
// Load decl names into diagnostic.
if (Decls.size() > 4)
PDiag << 0;
else {
PDiag << Decls.size();
for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(),
E = Decls.end();
I != E; ++I)
PDiag << (*I)->getDeclName();
}
// Load SourceRanges into diagnostic if there is room.
// Otherwise, load the SourceRange of the conditional expression.
if (Ranges.size() <= PartialDiagnostic::MaxArguments)
for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(),
E = Ranges.end();
I != E; ++I)
PDiag << *I;
else
PDiag << Second->getSourceRange();
S.Diag(Ranges.begin()->getBegin(), PDiag);
}
} // end namespace
StmtResult
Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
Stmt *First, FullExprArg second, Decl *secondVar,
FullExprArg third,
SourceLocation RParenLoc, Stmt *Body) {
if (!getLangOpts().CPlusPlus) {
if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
// C99 6.8.5p3: The declaration part of a 'for' statement shall only
// declare identifiers for objects having storage class 'auto' or
// 'register'.
for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end();
DI!=DE; ++DI) {
VarDecl *VD = dyn_cast<VarDecl>(*DI);
if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
VD = 0;
if (VD == 0)
Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for);
// FIXME: mark decl erroneous!
}
}
}
CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
ExprResult SecondResult(second.release());
VarDecl *ConditionVar = 0;
if (secondVar) {
ConditionVar = cast<VarDecl>(secondVar);
SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
if (SecondResult.isInvalid())
return StmtError();
}
Expr *Third = third.release().takeAs<Expr>();
DiagnoseUnusedExprResult(First);
DiagnoseUnusedExprResult(Third);
DiagnoseUnusedExprResult(Body);
if (isa<NullStmt>(Body))
getCurCompoundScope().setHasEmptyLoopBodies();
return Owned(new (Context) ForStmt(Context, First,
SecondResult.take(), ConditionVar,
Third, Body, ForLoc, LParenLoc,
RParenLoc));
}
/// In an Objective C collection iteration statement:
/// for (x in y)
/// x can be an arbitrary l-value expression. Bind it up as a
/// full-expression.
StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
// Reduce placeholder expressions here. Note that this rejects the
// use of pseudo-object l-values in this position.
ExprResult result = CheckPlaceholderExpr(E);
if (result.isInvalid()) return StmtError();
E = result.take();
CheckImplicitConversions(E);
result = MaybeCreateExprWithCleanups(E);
if (result.isInvalid()) return StmtError();
return Owned(static_cast<Stmt*>(result.take()));
}
ExprResult
Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
if (!collection)
return ExprError();
// Bail out early if we've got a type-dependent expression.
if (collection->isTypeDependent()) return Owned(collection);
// Perform normal l-value conversion.
ExprResult result = DefaultFunctionArrayLvalueConversion(collection);
if (result.isInvalid())
return ExprError();
collection = result.take();
// The operand needs to have object-pointer type.
// TODO: should we do a contextual conversion?
const ObjCObjectPointerType *pointerType =
collection->getType()->getAs<ObjCObjectPointerType>();
if (!pointerType)
return Diag(forLoc, diag::err_collection_expr_type)
<< collection->getType() << collection->getSourceRange();
// Check that the operand provides
// - countByEnumeratingWithState:objects:count:
const ObjCObjectType *objectType = pointerType->getObjectType();
ObjCInterfaceDecl *iface = objectType->getInterface();
// If we have a forward-declared type, we can't do this check.
// Under ARC, it is an error not to have a forward-declared class.
if (iface &&
RequireCompleteType(forLoc, QualType(objectType, 0),
getLangOpts().ObjCAutoRefCount
? diag::err_arc_collection_forward
: 0,
collection)) {
// Otherwise, if we have any useful type information, check that
// the type declares the appropriate method.
} else if (iface || !objectType->qual_empty()) {
IdentifierInfo *selectorIdents[] = {
&Context.Idents.get("countByEnumeratingWithState"),
&Context.Idents.get("objects"),
&Context.Idents.get("count")
};
Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
ObjCMethodDecl *method = 0;
// If there's an interface, look in both the public and private APIs.
if (iface) {
method = iface->lookupInstanceMethod(selector);
if (!method) method = iface->lookupPrivateMethod(selector);
}
// Also check protocol qualifiers.
if (!method)
method = LookupMethodInQualifiedType(selector, pointerType,
/*instance*/ true);
// If we didn't find it anywhere, give up.
if (!method) {
Diag(forLoc, diag::warn_collection_expr_type)
<< collection->getType() << selector << collection->getSourceRange();
}
// TODO: check for an incompatible signature?
}
// Wrap up any cleanups in the expression.
return Owned(MaybeCreateExprWithCleanups(collection));
}
StmtResult
Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
Stmt *First, Expr *collection,
SourceLocation RParenLoc) {
ExprResult CollectionExprResult =
CheckObjCForCollectionOperand(ForLoc, collection);
if (First) {
QualType FirstType;
if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
if (!DS->isSingleDecl())
return StmtError(Diag((*DS->decl_begin())->getLocation(),
diag::err_toomany_element_decls));
VarDecl *D = cast<VarDecl>(DS->getSingleDecl());
FirstType = D->getType();
// C99 6.8.5p3: The declaration part of a 'for' statement shall only
// declare identifiers for objects having storage class 'auto' or
// 'register'.
if (!D->hasLocalStorage())
return StmtError(Diag(D->getLocation(),
diag::err_non_variable_decl_in_for));
} else {
Expr *FirstE = cast<Expr>(First);
if (!FirstE->isTypeDependent() && !FirstE->isLValue())
return StmtError(Diag(First->getLocStart(),
diag::err_selector_element_not_lvalue)
<< First->getSourceRange());
FirstType = static_cast<Expr*>(First)->getType();
}
if (!FirstType->isDependentType() &&
!FirstType->isObjCObjectPointerType() &&
!FirstType->isBlockPointerType())
return StmtError(Diag(ForLoc, diag::err_selector_element_type)
<< FirstType << First->getSourceRange());
}
if (CollectionExprResult.isInvalid())
return StmtError();
return Owned(new (Context) ObjCForCollectionStmt(First,
CollectionExprResult.take(), 0,
ForLoc, RParenLoc));
}
namespace {
enum BeginEndFunction {
BEF_begin,
BEF_end
};
/// Build a variable declaration for a for-range statement.
static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
QualType Type, const char *Name) {
DeclContext *DC = SemaRef.CurContext;
IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
TInfo, SC_Auto, SC_None);
Decl->setImplicit();
return Decl;
}
/// Finish building a variable declaration for a for-range statement.
/// \return true if an error occurs.
static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
SourceLocation Loc, int diag) {
// Deduce the type for the iterator variable now rather than leaving it to
// AddInitializerToDecl, so we can produce a more suitable diagnostic.
TypeSourceInfo *InitTSI = 0;
if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) ==
Sema::DAR_Failed)
SemaRef.Diag(Loc, diag) << Init->getType();
if (!InitTSI) {
Decl->setInvalidDecl();
return true;
}
Decl->setTypeSourceInfo(InitTSI);
Decl->setType(InitTSI->getType());
// In ARC, infer lifetime.
// FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
// we're doing the equivalent of fast iteration.
if (SemaRef.getLangOpts().ObjCAutoRefCount &&
SemaRef.inferObjCARCLifetime(Decl))
Decl->setInvalidDecl();
SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false,
/*TypeMayContainAuto=*/false);
SemaRef.FinalizeDeclaration(Decl);
SemaRef.CurContext->addHiddenDecl(Decl);
return false;
}
/// Produce a note indicating which begin/end function was implicitly called
/// by a C++0x for-range statement. This is often not obvious from the code,
/// nor from the diagnostics produced when analysing the implicit expressions
/// required in a for-range statement.
void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
BeginEndFunction BEF) {
CallExpr *CE = dyn_cast<CallExpr>(E);
if (!CE)
return;
FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
if (!D)
return;
SourceLocation Loc = D->getLocation();
std::string Description;
bool IsTemplate = false;
if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
Description = SemaRef.getTemplateArgumentBindingsText(
FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
IsTemplate = true;
}
SemaRef.Diag(Loc, diag::note_for_range_begin_end)
<< BEF << IsTemplate << Description << E->getType();
}
/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the
/// given LookupResult is non-empty, it is assumed to describe a member which
/// will be invoked. Otherwise, the function will be found via argument
/// dependent lookup.
static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S,
SourceLocation Loc,
VarDecl *Decl,
BeginEndFunction BEF,
const DeclarationNameInfo &NameInfo,
LookupResult &MemberLookup,
Expr *Range) {
ExprResult CallExpr;
if (!MemberLookup.empty()) {
ExprResult MemberRef =
SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc,
/*IsPtr=*/false, CXXScopeSpec(),
/*TemplateKWLoc=*/SourceLocation(),
/*FirstQualifierInScope=*/0,
MemberLookup,
/*TemplateArgs=*/0);
if (MemberRef.isInvalid())
return ExprError();
CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(),
Loc, 0);
if (CallExpr.isInvalid())
return ExprError();
} else {
UnresolvedSet<0> FoundNames;
// C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace
// std is an associated namespace.
UnresolvedLookupExpr *Fn =
UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0,
NestedNameSpecifierLoc(), NameInfo,
/*NeedsADL=*/true, /*Overloaded=*/false,
FoundNames.begin(), FoundNames.end(),
/*LookInStdNamespace=*/true);
CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc,
0, /*AllowTypoCorrection=*/false);
if (CallExpr.isInvalid()) {
SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type)
<< Range->getType();
return ExprError();
}
}
if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc,
diag::err_for_range_iter_deduction_failure)) {
NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF);
return ExprError();
}
return CallExpr;
}
}
static bool ObjCEnumerationCollection(Expr *Collection) {
return !Collection->isTypeDependent()
&& Collection->getType()->getAs<ObjCObjectPointerType>() != 0;
}
/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
///
/// C++11 [stmt.ranged]:
/// A range-based for statement is equivalent to
///
/// {
/// auto && __range = range-init;
/// for ( auto __begin = begin-expr,
/// __end = end-expr;
/// __begin != __end;
/// ++__begin ) {
/// for-range-declaration = *__begin;
/// statement
/// }
/// }
///
/// The body of the loop is not available yet, since it cannot be analysed until
/// we have determined the type of the for-range-declaration.
StmtResult
Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc,
Stmt *First, SourceLocation ColonLoc, Expr *Range,
SourceLocation RParenLoc) {
if (!First || !Range)
return StmtError();
if (ObjCEnumerationCollection(Range))
return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
DeclStmt *DS = dyn_cast<DeclStmt>(First);
assert(DS && "first part of for range not a decl stmt");
if (!DS->isSingleDecl()) {
Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range);
return StmtError();
}
if (DS->getSingleDecl()->isInvalidDecl())
return StmtError();
if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression))
return StmtError();
// Build auto && __range = range-init
SourceLocation RangeLoc = Range->getLocStart();
VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
Context.getAutoRRefDeductType(),
"__range");
if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
diag::err_for_range_deduction_failure))
return StmtError();
// Claim the type doesn't contain auto: we've already done the checking.
DeclGroupPtrTy RangeGroup =
BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false);
StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
if (RangeDecl.isInvalid())
return StmtError();
return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(),
/*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS,
RParenLoc);
}
/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement.
StmtResult
Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc,
Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond,
Expr *Inc, Stmt *LoopVarDecl,
SourceLocation RParenLoc) {
Scope *S = getCurScope();
DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
QualType RangeVarType = RangeVar->getType();
DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
StmtResult BeginEndDecl = BeginEnd;
ExprResult NotEqExpr = Cond, IncrExpr = Inc;
if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) {
SourceLocation RangeLoc = RangeVar->getLocation();
const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
VK_LValue, ColonLoc);
if (BeginRangeRef.isInvalid())
return StmtError();
ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
VK_LValue, ColonLoc);
if (EndRangeRef.isInvalid())
return StmtError();
QualType AutoType = Context.getAutoDeductType();
Expr *Range = RangeVar->getInit();
if (!Range)
return StmtError();
QualType RangeType = Range->getType();
if (RequireCompleteType(RangeLoc, RangeType,
diag::err_for_range_incomplete_type))
return StmtError();
// Build auto __begin = begin-expr, __end = end-expr.
VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
"__begin");
VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
"__end");
// Build begin-expr and end-expr and attach to __begin and __end variables.
ExprResult BeginExpr, EndExpr;
if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
// - if _RangeT is an array type, begin-expr and end-expr are __range and
// __range + __bound, respectively, where __bound is the array bound. If
// _RangeT is an array of unknown size or an array of incomplete type,
// the program is ill-formed;
// begin-expr is __range.
BeginExpr = BeginRangeRef;
if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
diag::err_for_range_iter_deduction_failure)) {
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
return StmtError();
}
// Find the array bound.
ExprResult BoundExpr;
if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(),
Context.getPointerDiffType(),
RangeLoc));
else if (const VariableArrayType *VAT =
dyn_cast<VariableArrayType>(UnqAT))
BoundExpr = VAT->getSizeExpr();
else {
// Can't be a DependentSizedArrayType or an IncompleteArrayType since
// UnqAT is not incomplete and Range is not type-dependent.
llvm_unreachable("Unexpected array type in for-range");
}
// end-expr is __range + __bound.
EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
BoundExpr.get());
if (EndExpr.isInvalid())
return StmtError();
if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
diag::err_for_range_iter_deduction_failure)) {
NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
return StmtError();
}
} else {
DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"),
ColonLoc);
DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"),
ColonLoc);
LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName);
LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName);
if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
// - if _RangeT is a class type, the unqualified-ids begin and end are
// looked up in the scope of class _RangeT as if by class member access
// lookup (3.4.5), and if either (or both) finds at least one
// declaration, begin-expr and end-expr are __range.begin() and
// __range.end(), respectively;
LookupQualifiedName(BeginMemberLookup, D);
LookupQualifiedName(EndMemberLookup, D);
if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch)
<< RangeType << BeginMemberLookup.empty();
return StmtError();
}
} else {
// - otherwise, begin-expr and end-expr are begin(__range) and
// end(__range), respectively, where begin and end are looked up with
// argument-dependent lookup (3.4.2). For the purposes of this name
// lookup, namespace std is an associated namespace.
}
BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar,
BEF_begin, BeginNameInfo,
BeginMemberLookup,
BeginRangeRef.get());
if (BeginExpr.isInvalid())
return StmtError();
EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar,
BEF_end, EndNameInfo,
EndMemberLookup, EndRangeRef.get());
if (EndExpr.isInvalid())
return StmtError();
}
// C++0x [decl.spec.auto]p6: BeginType and EndType must be the same.
QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
if (!Context.hasSameType(BeginType, EndType)) {
Diag(RangeLoc, diag::err_for_range_begin_end_types_differ)
<< BeginType << EndType;
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
}
Decl *BeginEndDecls[] = { BeginVar, EndVar };
// Claim the type doesn't contain auto: we've already done the checking.
DeclGroupPtrTy BeginEndGroup =
BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false);
BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc);
const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
VK_LValue, ColonLoc);
if (BeginRef.isInvalid())
return StmtError();
ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
VK_LValue, ColonLoc);
if (EndRef.isInvalid())
return StmtError();
// Build and check __begin != __end expression.
NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
BeginRef.get(), EndRef.get());
NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get());
NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
if (NotEqExpr.isInvalid()) {
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
if (!Context.hasSameType(BeginType, EndType))
NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
return StmtError();
}
// Build and check ++__begin expression.
BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
VK_LValue, ColonLoc);
if (BeginRef.isInvalid())
return StmtError();
IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
if (IncrExpr.isInvalid()) {
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
return StmtError();
}
// Build and check *__begin expression.
BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
VK_LValue, ColonLoc);
if (BeginRef.isInvalid())
return StmtError();
ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
if (DerefExpr.isInvalid()) {
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
return StmtError();
}
// Attach *__begin as initializer for VD.
if (!LoopVar->isInvalidDecl()) {
AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false,
/*TypeMayContainAuto=*/true);
if (LoopVar->isInvalidDecl())
NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
}
} else {
// The range is implicitly used as a placeholder when it is dependent.
RangeVar->setUsed();
}
return Owned(new (Context) CXXForRangeStmt(RangeDS,
cast_or_null<DeclStmt>(BeginEndDecl.get()),
NotEqExpr.take(), IncrExpr.take(),
LoopVarDS, /*Body=*/0, ForLoc,
ColonLoc, RParenLoc));
}
/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
/// statement.
StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
if (!S || !B)
return StmtError();
ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);
ForStmt->setBody(B);
return S;
}
/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
/// body cannot be performed until after the type of the range variable is
/// determined.
StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
if (!S || !B)
return StmtError();
if (isa<ObjCForCollectionStmt>(S))
return FinishObjCForCollectionStmt(S, B);
CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
ForStmt->setBody(B);
DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
diag::warn_empty_range_based_for_body);
return S;
}
StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
SourceLocation LabelLoc,
LabelDecl *TheDecl) {
getCurFunction()->setHasBranchIntoScope();
TheDecl->setUsed();
return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc));
}
StmtResult
Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
Expr *E) {
// Convert operand to void*
if (!E->isTypeDependent()) {
QualType ETy = E->getType();
QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
ExprResult ExprRes = Owned(E);
AssignConvertType ConvTy =
CheckSingleAssignmentConstraints(DestTy, ExprRes);
if (ExprRes.isInvalid())
return StmtError();
E = ExprRes.take();
if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
return StmtError();
E = MaybeCreateExprWithCleanups(E);
}
getCurFunction()->setHasIndirectGoto();
return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E));
}
StmtResult
Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
Scope *S = CurScope->getContinueParent();
if (!S) {
// C99 6.8.6.2p1: A break shall appear only in or as a loop body.
return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
}
return Owned(new (Context) ContinueStmt(ContinueLoc));
}
StmtResult
Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
Scope *S = CurScope->getBreakParent();
if (!S) {
// C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
}
return Owned(new (Context) BreakStmt(BreakLoc));
}
/// \brief Determine whether the given expression is a candidate for
/// copy elision in either a return statement or a throw expression.
///
/// \param ReturnType If we're determining the copy elision candidate for
/// a return statement, this is the return type of the function. If we're
/// determining the copy elision candidate for a throw expression, this will
/// be a NULL type.
///
/// \param E The expression being returned from the function or block, or
/// being thrown.
///
/// \param AllowFunctionParameter Whether we allow function parameters to
/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but
/// we re-use this logic to determine whether we should try to move as part of
/// a return or throw (which does allow function parameters).
///
/// \returns The NRVO candidate variable, if the return statement may use the
/// NRVO, or NULL if there is no such candidate.
const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType,
Expr *E,
bool AllowFunctionParameter) {
QualType ExprType = E->getType();
// - in a return statement in a function with ...
// ... a class return type ...
if (!ReturnType.isNull()) {
if (!ReturnType->isRecordType())
return 0;
// ... the same cv-unqualified type as the function return type ...
if (!Context.hasSameUnqualifiedType(ReturnType, ExprType))
return 0;
}
// ... the expression is the name of a non-volatile automatic object
// (other than a function or catch-clause parameter)) ...
const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
if (!DR || DR->refersToEnclosingLocal())
return 0;
const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
if (!VD)
return 0;
// ...object (other than a function or catch-clause parameter)...
if (VD->getKind() != Decl::Var &&
!(AllowFunctionParameter && VD->getKind() == Decl::ParmVar))
return 0;
if (VD->isExceptionVariable()) return 0;
// ...automatic...
if (!VD->hasLocalStorage()) return 0;
// ...non-volatile...
if (VD->getType().isVolatileQualified()) return 0;
if (VD->getType()->isReferenceType()) return 0;
// __block variables can't be allocated in a way that permits NRVO.
if (VD->hasAttr<BlocksAttr>()) return 0;
// Variables with higher required alignment than their type's ABI
// alignment cannot use NRVO.
if (VD->hasAttr<AlignedAttr>() &&
Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType()))
return 0;
return VD;
}
/// \brief Perform the initialization of a potentially-movable value, which
/// is the result of return value.
///
/// This routine implements C++0x [class.copy]p33, which attempts to treat
/// returned lvalues as rvalues in certain cases (to prefer move construction),
/// then falls back to treating them as lvalues if that failed.
ExprResult
Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
const VarDecl *NRVOCandidate,
QualType ResultType,
Expr *Value,
bool AllowNRVO) {
// C++0x [class.copy]p33:
// When the criteria for elision of a copy operation are met or would
// be met save for the fact that the source object is a function
// parameter, and the object to be copied is designated by an lvalue,
// overload resolution to select the constructor for the copy is first
// performed as if the object were designated by an rvalue.
ExprResult Res = ExprError();
if (AllowNRVO &&
(NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) {
ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack,
Value->getType(), CK_NoOp, Value, VK_XValue);
Expr *InitExpr = &AsRvalue;
InitializationKind Kind
= InitializationKind::CreateCopy(Value->getLocStart(),
Value->getLocStart());
InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1);
// [...] If overload resolution fails, or if the type of the first
// parameter of the selected constructor is not an rvalue reference
// to the object's type (possibly cv-qualified), overload resolution
// is performed again, considering the object as an lvalue.
if (Seq) {
for (InitializationSequence::step_iterator Step = Seq.step_begin(),
StepEnd = Seq.step_end();
Step != StepEnd; ++Step) {
if (Step->Kind != InitializationSequence::SK_ConstructorInitialization)
continue;
CXXConstructorDecl *Constructor
= cast<CXXConstructorDecl>(Step->Function.Function);
const RValueReferenceType *RRefType
= Constructor->getParamDecl(0)->getType()
->getAs<RValueReferenceType>();
// If we don't meet the criteria, break out now.
if (!RRefType ||
!Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
Context.getTypeDeclType(Constructor->getParent())))
break;
// Promote "AsRvalue" to the heap, since we now need this
// expression node to persist.
Value = ImplicitCastExpr::Create(Context, Value->getType(),
CK_NoOp, Value, 0, VK_XValue);
// Complete type-checking the initialization of the return type
// using the constructor we found.
Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1));
}
}
}
// Either we didn't meet the criteria for treating an lvalue as an rvalue,
// above, or overload resolution failed. Either way, we need to try
// (again) now with the return value expression as written.
if (Res.isInvalid())
Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
return Res;
}
/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
/// for capturing scopes.
///
StmtResult
Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
// If this is the first return we've seen, infer the return type.
// [expr.prim.lambda]p4 in C++11; block literals follow a superset of those
// rules which allows multiple return statements.
CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
QualType FnRetType = CurCap->ReturnType;
// For blocks/lambdas with implicit return types, we check each return
// statement individually, and deduce the common return type when the block
// or lambda is completed.
if (CurCap->HasImplicitReturnType) {
if (RetValExp && !isa<InitListExpr>(RetValExp)) {
ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
if (Result.isInvalid())
return StmtError();
RetValExp = Result.take();
if (!RetValExp->isTypeDependent())
FnRetType = RetValExp->getType();
else
FnRetType = CurCap->ReturnType = Context.DependentTy;
} else {
if (RetValExp) {
// C++11 [expr.lambda.prim]p4 bans inferring the result from an
// initializer list, because it is not an expression (even
// though we represent it as one). We still deduce 'void'.
Diag(ReturnLoc, diag::err_lambda_return_init_list)
<< RetValExp->getSourceRange();
}
FnRetType = Context.VoidTy;
}
// Although we'll properly infer the type of the block once it's completed,
// make sure we provide a return type now for better error recovery.
if (CurCap->ReturnType.isNull())
CurCap->ReturnType = FnRetType;
}
assert(!FnRetType.isNull());
if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
return StmtError();
}
} else {
LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap);
if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){
Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
return StmtError();
}
}
// Otherwise, verify that this result type matches the previous one. We are
// pickier with blocks than for normal functions because we don't have GCC
// compatibility to worry about here.
const VarDecl *NRVOCandidate = 0;
if (FnRetType->isDependentType()) {
// Delay processing for now. TODO: there are lots of dependent
// types we can conclusively prove aren't void.
} else if (FnRetType->isVoidType()) {
if (RetValExp && !isa<InitListExpr>(RetValExp) &&
!(getLangOpts().CPlusPlus &&
(RetValExp->isTypeDependent() ||
RetValExp->getType()->isVoidType()))) {
if (!getLangOpts().CPlusPlus &&
RetValExp->getType()->isVoidType())
Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
else {
Diag(ReturnLoc, diag::err_return_block_has_expr);
RetValExp = 0;
}
}
} else if (!RetValExp) {
return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
} else if (!RetValExp->isTypeDependent()) {
// we have a non-void block with an expression, continue checking
// C99 6.8.6.4p3(136): The return statement is not an assignment. The
// overlap restriction of subclause 6.5.16.1 does not apply to the case of
// function return.
// In C++ the return statement is handled via a copy initialization.
// the C version of which boils down to CheckSingleAssignmentConstraints.
NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
FnRetType,
NRVOCandidate != 0);
ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
FnRetType, RetValExp);
if (Res.isInvalid()) {
// FIXME: Cleanup temporaries here, anyway?
return StmtError();
}
RetValExp = Res.take();
CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
}
if (RetValExp) {
CheckImplicitConversions(RetValExp, ReturnLoc);
RetValExp = MaybeCreateExprWithCleanups(RetValExp);
}
ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
NRVOCandidate);
// If we need to check for the named return value optimization,
// or if we need to infer the return type,
// save the return statement in our scope for later processing.
if (CurCap->HasImplicitReturnType ||
(getLangOpts().CPlusPlus && FnRetType->isRecordType() &&
!CurContext->isDependentContext()))
FunctionScopes.back()->Returns.push_back(Result);
return Owned(Result);
}
StmtResult
Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
// Check for unexpanded parameter packs.
if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
return StmtError();
if (isa<CapturingScopeInfo>(getCurFunction()))
return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
QualType FnRetType;
QualType RelatedRetType;
if (const FunctionDecl *FD = getCurFunctionDecl()) {
FnRetType = FD->getResultType();
if (FD->hasAttr<NoReturnAttr>() ||
FD->getType()->getAs<FunctionType>()->getNoReturnAttr())
Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
<< FD->getDeclName();
} else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
FnRetType = MD->getResultType();
if (MD->hasRelatedResultType() && MD->getClassInterface()) {
// In the implementation of a method with a related return type, the
// type used to type-check the validity of return statements within the
// method body is a pointer to the type of the class being implemented.
RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
}
} else // If we don't have a function/method context, bail.
return StmtError();
ReturnStmt *Result = 0;
if (FnRetType->isVoidType()) {
if (RetValExp) {
if (isa<InitListExpr>(RetValExp)) {
// We simply never allow init lists as the return value of void
// functions. This is compatible because this was never allowed before,
// so there's no legacy code to deal with.
NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
int FunctionKind = 0;
if (isa<ObjCMethodDecl>(CurDecl))
FunctionKind = 1;
else if (isa<CXXConstructorDecl>(CurDecl))
FunctionKind = 2;
else if (isa<CXXDestructorDecl>(CurDecl))
FunctionKind = 3;
Diag(ReturnLoc, diag::err_return_init_list)
<< CurDecl->getDeclName() << FunctionKind
<< RetValExp->getSourceRange();
// Drop the expression.
RetValExp = 0;
} else if (!RetValExp->isTypeDependent()) {
// C99 6.8.6.4p1 (ext_ since GCC warns)
unsigned D = diag::ext_return_has_expr;
if (RetValExp->getType()->isVoidType())
D = diag::ext_return_has_void_expr;
else {
ExprResult Result = Owned(RetValExp);
Result = IgnoredValueConversions(Result.take());
if (Result.isInvalid())
return StmtError();
RetValExp = Result.take();
RetValExp = ImpCastExprToType(RetValExp,
Context.VoidTy, CK_ToVoid).take();
}
// return (some void expression); is legal in C++.
if (D != diag::ext_return_has_void_expr ||
!getLangOpts().CPlusPlus) {
NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
int FunctionKind = 0;
if (isa<ObjCMethodDecl>(CurDecl))
FunctionKind = 1;
else if (isa<CXXConstructorDecl>(CurDecl))
FunctionKind = 2;
else if (isa<CXXDestructorDecl>(CurDecl))
FunctionKind = 3;
Diag(ReturnLoc, D)
<< CurDecl->getDeclName() << FunctionKind
<< RetValExp->getSourceRange();
}
}
if (RetValExp) {
CheckImplicitConversions(RetValExp, ReturnLoc);
RetValExp = MaybeCreateExprWithCleanups(RetValExp);
}
}
Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0);
} else if (!RetValExp && !FnRetType->isDependentType()) {
unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4
// C99 6.8.6.4p1 (ext_ since GCC warns)
if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr;
if (FunctionDecl *FD = getCurFunctionDecl())
Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
else
Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
Result = new (Context) ReturnStmt(ReturnLoc);
} else {
const VarDecl *NRVOCandidate = 0;
if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
// we have a non-void function with an expression, continue checking
if (!RelatedRetType.isNull()) {
// If we have a related result type, perform an extra conversion here.
// FIXME: The diagnostics here don't really describe what is happening.
InitializedEntity Entity =
InitializedEntity::InitializeTemporary(RelatedRetType);
ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(),
RetValExp);
if (Res.isInvalid()) {
// FIXME: Cleanup temporaries here, anyway?
return StmtError();
}
RetValExp = Res.takeAs<Expr>();
}
// C99 6.8.6.4p3(136): The return statement is not an assignment. The
// overlap restriction of subclause 6.5.16.1 does not apply to the case of
// function return.
// In C++ the return statement is handled via a copy initialization,
// the C version of which boils down to CheckSingleAssignmentConstraints.
NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,