//===--- 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/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.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/STLExtras.h"
#include "llvm/ADT/SmallVector.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 LeadingEmptyMacro) {
return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro));
}
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;
// suppress any potential 'unused variable' warning.
DG.getSingleDecl()->setUsed();
}
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;
if (E->isBoundMemberFunction(Context)) {
Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func)
<< E->getSourceRange();
return;
}
SourceLocation Loc;
SourceRange R1, R2;
if (!E->isUnusedResultAWarning(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();
E = E->IgnoreParenImpCasts();
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_call) << R1 << R2 << "warn_unused_result";
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)) {
const ObjCMethodDecl *MD = ME->getMethodDecl();
if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
return;
}
} else if (isa<ObjCPropertyRefExpr>(E)) {
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;
}
}
DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2);
}
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 (!getLangOptions().C99 && !getLangOptions().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]);
}
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");
// C99 6.8.4.2p3: The expression shall be an integer constant.
// However, GCC allows any evaluatable integer expression.
if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() &&
VerifyIntegerConstantExpression(LHSVal))
return StmtError();
// GCC extension: The expression shall be an integer constant.
if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() &&
VerifyIntegerConstantExpression(RHSVal)) {
RHSVal = 0; // Recover by just forgetting about it.
}
if (getCurFunction()->SwitchStack.empty()) {
Diag(CaseLoc, diag::err_case_not_in_switch);
return StmtError();
}
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) {
CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
CS->setSubStmt(SubStmt);
}
StmtResult
Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
Stmt *SubStmt, Scope *CurScope) {
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.
TheDecl->setLocation(IdentLoc);
LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
TheDecl->setStmt(LS);
TheDecl->setLocation(IdentLoc);
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);
// Warn if the if block has a null body without an else value.
// this helps prevent bugs due to typos, such as
// if (condition);
// do_stuff();
//
if (!elseStmt) {
if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
// But do not warn if the body is a macro that expands to nothing, e.g:
//
// #define CALL(x)
// if (condition)
// CALL(0);
//
if (!stmt->hasLeadingEmptyMacro())
Diag(stmt->getSemiLoc(), 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(const Expr* expr) {
if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) {
const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
QualType TypeBeforePromotion = ExprBeforePromotion->getType();
if (TypeBeforePromotion->isIntegralOrEnumerationType()) {
return TypeBeforePromotion;
}
}
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();
CondResult
= ConvertToIntegralOrEnumerationType(SwitchLoc, Cond,
PDiag(diag::err_typecheck_statement_requires_integer),
PDiag(diag::err_switch_incomplete_class_type)
<< Cond->getSourceRange(),
PDiag(diag::err_switch_explicit_conversion),
PDiag(diag::note_switch_conversion),
PDiag(diag::err_switch_multiple_conversions),
PDiag(diag::note_switch_conversion),
PDiag(0));
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();
if (SS->getCond() == 0)
return StmtError();
Expr *CondExpr = SS->getCond();
Expr *CondExprBeforePromotion = CondExpr;
QualType CondTypeBeforePromotion =
GetTypeBeforeIntegralPromotion(CondExpr);
// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
UsualUnaryConversions(CondExpr);
QualType CondType = CondExpr->getType();
SS->setCond(CondExpr);
// 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
: static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion));
bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType();
// 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 llvm::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);
// We already verified that the expression has a i-c-e value (C99
// 6.8.4.2p3) - get that value now.
Expr *Lo = CS->getLHS();
if (Lo->isTypeDependent() || Lo->isValueDependent()) {
HasDependentValue = true;
break;
}
llvm::APSInt LoVal = Lo->EvaluateAsInt(Context);
// Convert the value to the same width/sign as the condition.
ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
Lo->getLocStart(),
diag::warn_case_value_overflow);
// If the LHS is not the same type as the condition, insert an implicit
// cast.
ImpCastExprToType(Lo, CondType, CK_IntegralCast);
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;
bool ShouldCheckConstantCond = false;
if (!HasDependentValue && !TheDefaultStmt) {
Expr::EvalResult Result;
HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context);
if (HasConstantCond) {
assert(Result.Val.isInt() && "switch condition evaluated to non-int");
ConstantCondValue = Result.Val.getInt();
ShouldCheckConstantCond = true;
assert(ConstantCondValue.getBitWidth() == CondWidth &&
ConstantCondValue.isSigned() == CondIsSigned);
}
}
// 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.
Diag(CaseVals[i].second->getLHS()->getLocStart(),
diag::err_duplicate_case) << CaseVals[i].first.toString(10);
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 = Hi->EvaluateAsInt(Context);
// Convert the value to the same width/sign as the condition.
ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
Hi->getLocStart(),
diag::warn_case_value_overflow);
// If the LHS is not the same type as the condition, insert an implicit
// cast.
ImpCastExprToType(Hi, CondType, CK_IntegralCast);
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 llvm::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.
// TODO: we might want to check whether case values are out of the
// enum even if we don't want to check whether all cases are handled.
if (!TheDefaultStmt) {
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)
<< ED->getDeclName();
}
// 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)
<< ED->getDeclName();
}
llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(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)
<< ED->getDeclName();
}
}
// Check which enum vals aren't in switch
CaseValsTy::const_iterator CI = CaseVals.begin();
CaseRangesTy::const_iterator RI = CaseRanges.begin();
bool hasCasesNotInSwitch = false;
llvm::SmallVector<DeclarationName,8> UnhandledNames;
for (EnumValsTy::const_iterator 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()->EvaluateAsInt(Context);
AdjustAPSInt(Hi, CondWidth, CondIsSigned);
if (EI->first <= Hi)
break;
}
if (RI == CaseRanges.end() || EI->first < RI->first) {
hasCasesNotInSwitch = true;
if (!TheDefaultStmt)
UnhandledNames.push_back(EI->second->getDeclName());
}
}
// Produce a nice diagnostic if multiple values aren't handled.
switch (UnhandledNames.size()) {
case 0: break;
case 1:
Diag(CondExpr->getExprLoc(), diag::warn_missing_case1)
<< UnhandledNames[0];
break;
case 2:
Diag(CondExpr->getExprLoc(), diag::warn_missing_case2)
<< UnhandledNames[0] << UnhandledNames[1];
break;
case 3:
Diag(CondExpr->getExprLoc(), diag::warn_missing_case3)
<< UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
break;
default:
Diag(CondExpr->getExprLoc(), diag::warn_missing_cases)
<< (unsigned)UnhandledNames.size()
<< UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
break;
}
if (!hasCasesNotInSwitch)
SS->setAllEnumCasesCovered();
}
}
// 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);
}
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);
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");
if (CheckBooleanCondition(Cond, DoLoc))
return StmtError();
CheckImplicitConversions(Cond, DoLoc);
ExprResult CondResult = MaybeCreateExprWithCleanups(Cond);
if (CondResult.isInvalid())
return StmtError();
Cond = CondResult.take();
DiagnoseUnusedExprResult(Body);
return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen));
}
StmtResult
Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
Stmt *First, FullExprArg second, Decl *secondVar,
FullExprArg third,
SourceLocation RParenLoc, Stmt *Body) {
if (!getLangOptions().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!
}
}
}
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);
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) {
CheckImplicitConversions(E);
ExprResult Result = MaybeCreateExprWithCleanups(E);
if (Result.isInvalid()) return StmtError();
return Owned(static_cast<Stmt*>(Result.get()));
}
StmtResult
Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
SourceLocation LParenLoc,
Stmt *First, Expr *Second,
SourceLocation RParenLoc, Stmt *Body) {
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));
Decl *D = DS->getSingleDecl();
FirstType = cast<ValueDecl>(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'.
VarDecl *VD = cast<VarDecl>(D);
if (VD->isLocalVarDecl() && !VD->hasLocalStorage())
return StmtError(Diag(VD->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())
Diag(ForLoc, diag::err_selector_element_type)
<< FirstType << First->getSourceRange();
}
if (Second && !Second->isTypeDependent()) {
DefaultFunctionArrayLvalueConversion(Second);
QualType SecondType = Second->getType();
if (!SecondType->isObjCObjectPointerType())
Diag(ForLoc, diag::err_collection_expr_type)
<< SecondType << Second->getSourceRange();
else if (const ObjCObjectPointerType *OPT =
SecondType->getAsObjCInterfacePointerType()) {
llvm::SmallVector<IdentifierInfo *, 4> KeyIdents;
IdentifierInfo* selIdent =
&Context.Idents.get("countByEnumeratingWithState");
KeyIdents.push_back(selIdent);
selIdent = &Context.Idents.get("objects");
KeyIdents.push_back(selIdent);
selIdent = &Context.Idents.get("count");
KeyIdents.push_back(selIdent);
Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]);
if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) {
if (!IDecl->isForwardDecl() &&
!IDecl->lookupInstanceMethod(CSelector)) {
// Must further look into private implementation methods.
if (!LookupPrivateInstanceMethod(CSelector, IDecl))
Diag(ForLoc, diag::warn_collection_expr_type)
<< SecondType << CSelector << Second->getSourceRange();
}
}
}
}
return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body,
ForLoc, RParenLoc));
}
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());
AssignConvertType ConvTy =
CheckSingleAssignmentConstraints(DestTy, E);
if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
return StmtError();
}
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
///
/// \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)
return 0;
const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
if (!VD)
return 0;
if (VD->hasLocalStorage() && !VD->isExceptionVariable() &&
!VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() &&
!VD->getType().isVolatileQualified() &&
((VD->getKind() == Decl::Var) ||
(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)))
return VD;
return 0;
}
/// \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) {
// 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 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true)) {
ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack,
Value->getType(), CK_LValueToRValue,
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.getKind() != InitializationSequence::FailedSequence) {
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_LValueToRValue, 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;
}
/// ActOnBlockReturnStmt - Utility routine to figure out block's return type.
///
StmtResult
Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
// If this is the first return we've seen in the block, infer the type of
// the block from it.
BlockScopeInfo *CurBlock = getCurBlock();
if (CurBlock->ReturnType.isNull()) {
if (RetValExp) {
// Don't call UsualUnaryConversions(), since we don't want to do
// integer promotions here.
DefaultFunctionArrayLvalueConversion(RetValExp);
CurBlock->ReturnType = RetValExp->getType();
if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) {
// We have to remove a 'const' added to copied-in variable which was
// part of the implementation spec. and not the actual qualifier for
// the variable.
if (CDRE->isConstQualAdded())
CurBlock->ReturnType.removeLocalConst(); // FIXME: local???
}
} else
CurBlock->ReturnType = Context.VoidTy;
}
QualType FnRetType = CurBlock->ReturnType;
if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr)
<< getCurFunctionOrMethodDecl()->getDeclName();
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.
ReturnStmt *Result = 0;
if (CurBlock->ReturnType->isVoidType()) {
if (RetValExp) {
Diag(ReturnLoc, diag::err_return_block_has_expr);
RetValExp = 0;
}
Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0);
} else if (!RetValExp) {
return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
} else {
const VarDecl *NRVOCandidate = 0;
if (!FnRetType->isDependentType() && !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();
}
if (RetValExp) {
CheckImplicitConversions(RetValExp, ReturnLoc);
RetValExp = MaybeCreateExprWithCleanups(RetValExp);
}
RetValExp = Res.takeAs<Expr>();
if (RetValExp)
CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
}
Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
}
// If we need to check for the named return value optimization, save the
// return statement in our scope for later processing.
if (getLangOptions().CPlusPlus && FnRetType->isRecordType() &&
!CurContext->isDependentContext())
FunctionScopes.back()->Returns.push_back(Result);
return Owned(Result);
}
StmtResult
Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
if (getCurBlock())
return ActOnBlockReturnStmt(ReturnLoc, RetValExp);
QualType FnRetType;
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)
<< getCurFunctionOrMethodDecl()->getDeclName();
} else if (ObjCMethodDecl *MD = getCurMethodDecl())
FnRetType = MD->getResultType();
else // If we don't have a function/method context, bail.
return StmtError();
ReturnStmt *Result = 0;
if (FnRetType->isVoidType()) {
if (RetValExp && !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 {
IgnoredValueConversions(RetValExp);
ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid);
}
// return (some void expression); is legal in C++.
if (D != diag::ext_return_has_void_expr ||
!getLangOptions().CPlusPlus) {
NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
Diag(ReturnLoc, D)
<< CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl)
<< RetValExp->getSourceRange();
}
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 (getLangOptions().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
// 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.takeAs<Expr>();
if (RetValExp)
CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
}
if (RetValExp) {
CheckImplicitConversions(RetValExp, ReturnLoc);
RetValExp = MaybeCreateExprWithCleanups(RetValExp);
}
Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
}
// If we need to check for the named return value optimization, save the
// return statement in our scope for later processing.
if (getLangOptions().CPlusPlus && FnRetType->isRecordType() &&
!CurContext->isDependentContext())
FunctionScopes.back()->Returns.push_back(Result);
return Owned(Result);
}
/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
/// ignore "noop" casts in places where an lvalue is required by an inline asm.
/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
/// provide a strong guidance to not use it.
///
/// This method checks to see if the argument is an acceptable l-value and
/// returns false if it is a case we can handle.
static bool CheckAsmLValue(const Expr *E, Sema &S) {
// Type dependent expressions will be checked during instantiation.
if (E->isTypeDependent())
return false;
if (E->isLValue())
return false; // Cool, this is an lvalue.
// Okay, this is not an lvalue, but perhaps it is the result of a cast that we
// are supposed to allow.
const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
if (E != E2 && E2->isLValue()) {
if (!S.getLangOptions().HeinousExtensions)
S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
<< E->getSourceRange();
else
S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
<< E->getSourceRange();
// Accept, even if we emitted an error diagnostic.
return false;
}
// None of the above, just randomly invalid non-lvalue.
return true;
}
StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
bool IsSimple,
bool IsVolatile,
unsigned NumOutputs,
unsigned NumInputs,
IdentifierInfo **Names,
MultiExprArg constraints,
MultiExprArg exprs,
Expr *asmString,
MultiExprArg clobbers,
SourceLocation RParenLoc,
bool MSAsm) {
unsigned NumClobbers = clobbers.size();
StringLiteral **Constraints =
reinterpret_cast<StringLiteral**>(constraints.get());
Expr **Exprs = exprs.get();
StringLiteral *AsmString = cast<StringLiteral>(asmString);
StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
// The parser verifies that there is a string literal here.
if (AsmString->isWide())
return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
<< AsmString->getSourceRange());
for (unsigned i = 0; i != NumOutputs; i++) {
StringLiteral *Literal = Constraints[i];
if (Literal->isWide())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
llvm::StringRef OutputName;
if (Names[i])
OutputName = Names[i]->getName();
TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
if (!Context.Target.validateOutputConstraint(Info))
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_invalid_output_constraint)
<< Info.getConstraintStr());
// Check that the output exprs are valid lvalues.
Expr *OutputExpr = Exprs[i];
if (CheckAsmLValue(OutputExpr, *this)) {
return StmtError(Diag(OutputExpr->getLocStart(),
diag::err_asm_invalid_lvalue_in_output)
<< OutputExpr->getSourceRange());
}
OutputConstraintInfos.push_back(Info);
}
llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
StringLiteral *Literal = Constraints[i];
if (Literal->isWide())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
llvm::StringRef InputName;
if (Names[i])
InputName = Names[i]->getName();
TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(),
NumOutputs, Info)) {
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_invalid_input_constraint)
<< Info.getConstraintStr());
}
Expr *InputExpr = Exprs[i];
// Only allow void types for memory constraints.
if (Info.allowsMemory() && !Info.allowsRegister()) {
if (CheckAsmLValue(InputExpr, *this))
return StmtError(Diag(InputExpr->getLocStart(),
diag::err_asm_invalid_lvalue_in_input)
<< Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
if (Info.allowsRegister()) {
if (InputExpr->getType()->isVoidType()) {
return StmtError(Diag(InputExpr->getLocStart(),
diag::err_asm_invalid_type_in_input)
<< InputExpr->getType() << Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
}
DefaultFunctionArrayLvalueConversion(Exprs[i]);
InputConstraintInfos.push_back(Info);
}
// Check that the clobbers are valid.
for (unsigned i = 0; i != NumClobbers; i++) {
StringLiteral *Literal = Clobbers[i];
if (Literal->isWide())
return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
<< Literal->getSourceRange());
llvm::StringRef Clobber = Literal->getString();
if (!Context.Target.isValidGCCRegisterName(Clobber))
return StmtError(Diag(Literal->getLocStart(),
diag::err_asm_unknown_register_name) << Clobber);
}
AsmStmt *NS =
new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm,
NumOutputs, NumInputs, Names, Constraints, Exprs,
AsmString, NumClobbers, Clobbers, RParenLoc);
// Validate the asm string, ensuring it makes sense given the operands we
// have.
llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
unsigned DiagOffs;
if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
<< AsmString->getSourceRange();
return StmtError();
}
// Validate tied input operands for type mismatches.
for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
// If this is a tied constraint, verify that the output and input have
// either exactly the same type, or that they are int/ptr operands with the
// same size (int/long, int*/long, are ok etc).
if (!Info.hasTiedOperand()) continue;
unsigned TiedTo = Info.getTiedOperand();
Expr *OutputExpr = Exprs[TiedTo];
Expr *InputExpr = Exprs[i+NumOutputs];
QualType InTy = InputExpr->getType();
QualType OutTy = OutputExpr->getType();
if (Context.hasSameType(InTy, OutTy))
continue; // All types can be tied to themselves.
// Decide if the input and output are in the same domain (integer/ptr or
// floating point.
enum AsmDomain {
AD_Int, AD_FP, AD_Other
} InputDomain, OutputDomain;
if (InTy->isIntegerType() || InTy->isPointerType())
InputDomain = AD_Int;
else if (InTy->isRealFloatingType())
InputDomain = AD_FP;
else
InputDomain = AD_Other;
if (OutTy->isIntegerType() || OutTy->isPointerType())
OutputDomain = AD_Int;
else if (OutTy->isRealFloatingType())
OutputDomain = AD_FP;
else
OutputDomain = AD_Other;
// They are ok if they are the same size and in the same domain. This
// allows tying things like:
// void* to int*
// void* to int if they are the same size.
// double to long double if they are the same size.
//
uint64_t OutSize = Context.getTypeSize(OutTy);
uint64_t InSize = Context.getTypeSize(InTy);
if (OutSize == InSize && InputDomain == OutputDomain &&
InputDomain != AD_Other)
continue;
// If the smaller input/output operand is not mentioned in the asm string,
// then we can promote it and the asm string won't notice. Check this
// case now.
bool SmallerValueMentioned = false;
for (unsigned p = 0, e = Pieces.size(); p != e; ++p) {
AsmStmt::AsmStringPiece &Piece = Pieces[p];
if (!Piece.isOperand()) continue;
// If this is a reference to the input and if the input was the smaller
// one, then we have to reject this asm.
if (Piece.getOperandNo() == i+NumOutputs) {
if (InSize < OutSize) {
SmallerValueMentioned = true;
break;
}
}
// If this is a reference to the input and if the input was the smaller
// one, then we have to reject this asm.
if (Piece.getOperandNo() == TiedTo) {
if (InSize > OutSize) {
SmallerValueMentioned = true;
break;
}
}
}
// If the smaller value wasn't mentioned in the asm string, and if the
// output was a register, just extend the shorter one to the size of the
// larger one.
if (!SmallerValueMentioned && InputDomain != AD_Other &&
OutputConstraintInfos[TiedTo].allowsRegister())
continue;
Diag(InputExpr->getLocStart(),
diag::err_asm_tying_incompatible_types)
<< InTy << OutTy << OutputExpr->getSourceRange()
<< InputExpr->getSourceRange();
return StmtError();
}
return Owned(NS);
}
StmtResult
Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
SourceLocation RParen, Decl *Parm,
Stmt *Body) {
VarDecl *Var = cast_or_null<VarDecl>(Parm);
if (Var && Var->isInvalidDecl())
return StmtError();
return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body));
}
StmtResult
Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body));
}
StmtResult
Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
MultiStmtArg CatchStmts, Stmt *Finally) {
if (!getLangOptions().ObjCExceptions)
Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
getCurFunction()->setHasBranchProtectedScope();
unsigned NumCatchStmts = CatchStmts.size();
return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try,
CatchStmts.release(),
NumCatchStmts,
Finally));
}
StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc,
Expr *Throw) {
if (Throw) {
DefaultLvalueConversion(Throw);
QualType ThrowType = Throw->getType();
// Make sure the expression type is an ObjC pointer or "void *".
if (!ThrowType->isDependentType() &&
!ThrowType->isObjCObjectPointerType()) {
const PointerType *PT = ThrowType->getAs<PointerType>();
if (!PT || !PT->getPointeeType()->isVoidType())
return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
<< Throw->getType() << Throw->getSourceRange());
}
}
return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw));
}
StmtResult
Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
Scope *CurScope) {
if (!getLangOptions().ObjCExceptions)
Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
if (!Throw) {
// @throw without an expression designates a rethrow (which much occur
// in the context of an @catch clause).
Scope *AtCatchParent = CurScope;
while (AtCatchParent && !AtCatchParent->isAtCatchScope())
AtCatchParent = AtCatchParent->getParent();
if (!AtCatchParent)
return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
}
return BuildObjCAtThrowStmt(AtLoc, Throw);
}
StmtResult
Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
Stmt *SyncBody) {
getCurFunction()->setHasBranchProtectedScope();
DefaultLvalueConversion(SyncExpr);
// Make sure the expression type is an ObjC pointer or "void *".
if (!SyncExpr->getType()->isDependentType() &&
!SyncExpr->getType()->isObjCObjectPointerType()) {
const PointerType *PT = SyncExpr->getType()->getAs<PointerType>();
if (!PT || !PT->getPointeeType()->isVoidType())
return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object)
<< SyncExpr->getType() << SyncExpr->getSourceRange());
}
return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody));
}
/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
/// and creates a proper catch handler from them.
StmtResult
Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
Stmt *HandlerBlock) {
// There's nothing to test that ActOnExceptionDecl didn't already test.
return Owned(new (Context) CXXCatchStmt(CatchLoc,
cast_or_null<VarDecl>(ExDecl),
HandlerBlock));
}
namespace {
class TypeWithHandler {
QualType t;
CXXCatchStmt *stmt;
public:
TypeWithHandler(const QualType &type, CXXCatchStmt *statement)
: t(type), stmt(statement) {}
// An arbitrary order is fine as long as it places identical
// types next to each other.
bool operator<(const TypeWithHandler &y) const {
if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr())
return true;
if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr())
return false;
else
return getTypeSpecStartLoc() < y.getTypeSpecStartLoc();
}
bool operator==(const TypeWithHandler& other) const {
return t == other.t;
}
CXXCatchStmt *getCatchStmt() const { return stmt; }
SourceLocation getTypeSpecStartLoc() const {
return stmt->getExceptionDecl()->getTypeSpecStartLoc();
}
};
}
/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
/// handlers and creates a try statement from them.
StmtResult
Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
MultiStmtArg RawHandlers) {
if (!getLangOptions().Exceptions)
Diag(TryLoc, diag::err_exceptions_disabled) << "try";
unsigned NumHandlers = RawHandlers.size();
assert(NumHandlers > 0 &&
"The parser shouldn't call this if there are no handlers.");
Stmt **Handlers = RawHandlers.get();
llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers;
for (unsigned i = 0; i < NumHandlers; ++i) {
CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]);
if (!Handler->getExceptionDecl()) {
if (i < NumHandlers - 1)
return StmtError(Diag(Handler->getLocStart(),
diag::err_early_catch_all));
continue;
}
const QualType CaughtType = Handler->getCaughtType();
const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType);
TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler));
}
// Detect handlers for the same type as an earlier one.
if (NumHandlers > 1) {
llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end());
TypeWithHandler prev = TypesWithHandlers[0];
for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) {
TypeWithHandler curr = TypesWithHandlers[i];
if (curr == prev) {
Diag(curr.getTypeSpecStartLoc(),
diag::warn_exception_caught_by_earlier_handler)
<< curr.getCatchStmt()->getCaughtType().getAsString();
Diag(prev.getTypeSpecStartLoc(),
diag::note_previous_exception_handler)
<< prev.getCatchStmt()->getCaughtType().getAsString();
}
prev = curr;
}
}
getCurFunction()->setHasBranchProtectedScope();
// FIXME: We should detect handlers that cannot catch anything because an
// earlier handler catches a superclass. Need to find a method that is not
// quadratic for this.
// Neither of these are explicitly forbidden, but every compiler detects them
// and warns.
return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock,
Handlers, NumHandlers));
}