Add noreturn support for blocks.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@77377 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mike Stump 2009-07-28 22:04:01 +00:00
Родитель fa9f8b4cf9
Коммит 5692586ae5
7 изменённых файлов: 75 добавлений и 5 удалений

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@ -110,6 +110,10 @@ def warn_maybe_falloff_nonvoid_function : Warning<
def warn_falloff_nonvoid_function : Warning<
"control reaches end of non-void function">,
InGroup<ReturnType>;
def err_maybe_falloff_nonvoid_block : Error<
"control may reach end of non-void block">;
def err_falloff_nonvoid_block : Error<
"control reaches end of non-void block">;
/// Built-in functions.
def ext_implicit_lib_function_decl : ExtWarn<

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@ -802,8 +802,9 @@ public:
SourceLocation MemberLoc,
IdentifierInfo &Member);
/// Helpers for dealing with functions.
/// Helpers for dealing with blocks and functions.
void CheckFallThroughForFunctionDef(Decl *D, Stmt *Body);
void CheckFallThroughForBlock(QualType BlockTy, Stmt *Body);
bool CheckParmsForFunctionDef(FunctionDecl *FD);
void CheckCXXDefaultArguments(FunctionDecl *FD);
void CheckExtraCXXDefaultArguments(Declarator &D);

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@ -1124,8 +1124,8 @@ Sema::ControlFlowKind Sema::CheckFallThrough(Stmt *Root) {
/// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a
/// function that should return a value. Check that we don't fall off the end
/// of a noreturn function. We assume that functions not marked noreturn will
/// return.
/// of a noreturn function. We assume that functions and blocks not marked
/// noreturn will return.
void Sema::CheckFallThroughForFunctionDef(Decl *D, Stmt *Body) {
// FIXME: Would be nice if we had a better way to control cascading errors,
// but for now, avoid them. The problem is that when Parse sees:
@ -1175,6 +1175,51 @@ void Sema::CheckFallThroughForFunctionDef(Decl *D, Stmt *Body) {
}
}
/// CheckFallThroughForBlock - Check that we don't fall off the end of a block
/// that should return a value. Check that we don't fall off the end of a
/// noreturn block. We assume that functions and blocks not marked noreturn
/// will return.
void Sema::CheckFallThroughForBlock(QualType BlockTy, Stmt *Body) {
// FIXME: Would be nice if we had a better way to control cascading errors,
// but for now, avoid them. The problem is that when Parse sees:
// int foo() { return a; }
// The return is eaten and the Sema code sees just:
// int foo() { }
// which this code would then warn about.
if (getDiagnostics().hasErrorOccurred())
return;
bool ReturnsVoid = false;
bool HasNoReturn = false;
if (const FunctionType *FT = BlockTy->getPointeeType()->getAsFunctionType()) {
if (FT->getResultType()->isVoidType())
ReturnsVoid = true;
if (FT->getNoReturnAttr())
HasNoReturn = true;
}
if (ReturnsVoid && !HasNoReturn)
return;
// FIXME: Funtion try block
if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
switch (CheckFallThrough(Body)) {
case MaybeFallThrough:
if (HasNoReturn)
Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
else if (!ReturnsVoid)
Diag(Compound->getRBracLoc(), diag::err_maybe_falloff_nonvoid_block);
break;
case AlwaysFallThrough:
if (HasNoReturn)
Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
else if (!ReturnsVoid)
Diag(Compound->getRBracLoc(), diag::err_falloff_nonvoid_block);
break;
case NeverFallThrough:
break;
}
}
}
/// CheckParmsForFunctionDef - Check that the parameters of the given
/// function are appropriate for the definition of a function. This
/// takes care of any checks that cannot be performed on the

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@ -5490,12 +5490,15 @@ Sema::OwningExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
for (unsigned i = 0, e = BSI->Params.size(); i != e; ++i)
ArgTypes.push_back(BSI->Params[i]->getType());
bool NoReturn = BSI->TheDecl->getAttr<NoReturnAttr>();
QualType BlockTy;
if (!BSI->hasPrototype)
BlockTy = Context.getFunctionType(RetTy, 0, 0, false, 0);
BlockTy = Context.getFunctionType(RetTy, 0, 0, false, 0, false, false, 0, 0,
NoReturn);
else
BlockTy = Context.getFunctionType(RetTy, ArgTypes.data(), ArgTypes.size(),
BSI->isVariadic, 0);
BSI->isVariadic, 0, false, false, 0, 0,
NoReturn);
// FIXME: Check that return/parameter types are complete/non-abstract
DiagnoseUnusedParameters(BSI->Params.begin(), BSI->Params.end());
@ -5507,6 +5510,7 @@ Sema::OwningExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
CurFunctionNeedsScopeChecking = BSI->SavedFunctionNeedsScopeChecking;
BSI->TheDecl->setBody(body.takeAs<CompoundStmt>());
CheckFallThroughForBlock(BlockTy, BSI->TheDecl->getBody());
return Owned(new (Context) BlockExpr(BSI->TheDecl, BlockTy,
BSI->hasBlockDeclRefExprs));
}

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@ -0,0 +1,6 @@
// RUN: clang-cc -fsyntax-only %s -verify -fblocks
int j;
void foo() {
^ (void) { if (j) return 1; }(); // expected-error {{control may reach end of non-void block}}
}

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@ -0,0 +1,5 @@
// RUN: clang-cc -fsyntax-only %s -verify -fblocks
void foo() {
^ (void) __attribute__((noreturn)) { }(); // expected-error {{block declared 'noreturn' should not return}}
}

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@ -0,0 +1,5 @@
// RUN: clang-cc -fsyntax-only %s -verify -fblocks
void foo() {
^ int (void) { }(); // expected-error {{control reaches end of non-void block}}
}