PR40642: Fix determination of whether the final statement of a statement
expression is a discarded-value expression.
Summary:
We used to get this wrong in three ways:
1) During parsing, an expression-statement followed by the }) ending a
statement expression was always treated as producing the value of the
statement expression. That's wrong for ({ if (1) expr; })
2) During template instantiation, various kinds of statement (most
statements not appearing directly in a compound-statement) were not
treated as discarded-value expressions, resulting in missing volatile
loads (etc).
3) In all contexts, an expression-statement with attributes was not
treated as producing the value of the statement expression, eg
({ [[attr]] expr; }).
Also fix incorrect enforcement of OpenMP rule that directives can "only
be placed in the program at a position where ignoring or deleting the
directive would result in a program with correct syntax". In particular,
a label (be it goto, case, or default) should not affect whether
directives are permitted.
Reviewers: aaron.ballman, rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D57984
llvm-svn: 354090
diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index d1a4dc0..f2bb289 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -320,6 +320,23 @@
return New;
}
+const Expr *ValueStmt::getExprStmt() const {
+ const Stmt *S = this;
+ do {
+ if (const auto *E = dyn_cast<Expr>(S))
+ return E;
+
+ if (const auto *LS = dyn_cast<LabelStmt>(S))
+ S = LS->getSubStmt();
+ else if (const auto *AS = dyn_cast<AttributedStmt>(S))
+ S = AS->getSubStmt();
+ else
+ llvm_unreachable("unknown kind of ValueStmt");
+ } while (isa<ValueStmt>(S));
+
+ return nullptr;
+}
+
const char *LabelStmt::getName() const {
return getDecl()->getIdentifier()->getNameStart();
}
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index db3f4f1..5b5113b 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -391,26 +391,35 @@
// at the end of a statement expression, they yield the value of their
// subexpression. Handle this by walking through all labels we encounter,
// emitting them before we evaluate the subexpr.
+ // Similar issues arise for attributed statements.
const Stmt *LastStmt = S.body_back();
- while (const LabelStmt *LS = dyn_cast<LabelStmt>(LastStmt)) {
- EmitLabel(LS->getDecl());
- LastStmt = LS->getSubStmt();
+ while (!isa<Expr>(LastStmt)) {
+ if (const auto *LS = dyn_cast<LabelStmt>(LastStmt)) {
+ EmitLabel(LS->getDecl());
+ LastStmt = LS->getSubStmt();
+ } else if (const auto *AS = dyn_cast<AttributedStmt>(LastStmt)) {
+ // FIXME: Update this if we ever have attributes that affect the
+ // semantics of an expression.
+ LastStmt = AS->getSubStmt();
+ } else {
+ llvm_unreachable("unknown value statement");
+ }
}
EnsureInsertPoint();
- QualType ExprTy = cast<Expr>(LastStmt)->getType();
+ const Expr *E = cast<Expr>(LastStmt);
+ QualType ExprTy = E->getType();
if (hasAggregateEvaluationKind(ExprTy)) {
- EmitAggExpr(cast<Expr>(LastStmt), AggSlot);
+ EmitAggExpr(E, AggSlot);
} else {
// We can't return an RValue here because there might be cleanups at
// the end of the StmtExpr. Because of that, we have to emit the result
// here into a temporary alloca.
RetAlloca = CreateMemTemp(ExprTy);
- EmitAnyExprToMem(cast<Expr>(LastStmt), RetAlloca, Qualifiers(),
- /*IsInit*/false);
+ EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
+ /*IsInit*/ false);
}
-
}
return RetAlloca;
diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 0a1dbf7..5ac01f6 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -2703,7 +2703,8 @@
return MDecl;
}
-StmtResult Parser::ParseObjCAtStatement(SourceLocation AtLoc) {
+StmtResult Parser::ParseObjCAtStatement(SourceLocation AtLoc,
+ ParsedStmtContext StmtCtx) {
if (Tok.is(tok::code_completion)) {
Actions.CodeCompleteObjCAtStatement(getCurScope());
cutOffParsing();
@@ -2740,7 +2741,7 @@
// Otherwise, eat the semicolon.
ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
- return Actions.ActOnExprStmt(Res, isExprValueDiscarded());
+ return handleExprStmt(Res, StmtCtx);
}
ExprResult Parser::ParseObjCAtExpression(SourceLocation AtLoc) {
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 5b8670e..d046341 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -1132,8 +1132,8 @@
/// 'target teams distribute simd' {clause}
/// annot_pragma_openmp_end
///
-StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
- AllowedConstructsKind Allowed) {
+StmtResult
+Parser::ParseOpenMPDeclarativeOrExecutableDirective(ParsedStmtContext StmtCtx) {
assert(Tok.is(tok::annot_pragma_openmp) && "Not an OpenMP directive!");
ParenBraceBracketBalancer BalancerRAIIObj(*this);
SmallVector<OMPClause *, 5> Clauses;
@@ -1152,7 +1152,9 @@
switch (DKind) {
case OMPD_threadprivate: {
- if (Allowed != ACK_Any) {
+ // FIXME: Should this be permitted in C++?
+ if ((StmtCtx & ParsedStmtContext::AllowDeclarationsInC) ==
+ ParsedStmtContext()) {
Diag(Tok, diag::err_omp_immediate_directive)
<< getOpenMPDirectiveName(DKind) << 0;
}
@@ -1219,7 +1221,8 @@
case OMPD_target_enter_data:
case OMPD_target_exit_data:
case OMPD_target_update:
- if (Allowed == ACK_StatementsOpenMPNonStandalone) {
+ if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
+ ParsedStmtContext()) {
Diag(Tok, diag::err_omp_immediate_directive)
<< getOpenMPDirectiveName(DKind) << 0;
}
@@ -1322,7 +1325,8 @@
// If the depend clause is specified, the ordered construct is a stand-alone
// directive.
if (DKind == OMPD_ordered && FirstClauses[OMPC_depend].getInt()) {
- if (Allowed == ACK_StatementsOpenMPNonStandalone) {
+ if ((StmtCtx & ParsedStmtContext::AllowStandaloneOpenMPDirectives) ==
+ ParsedStmtContext()) {
Diag(Loc, diag::err_omp_immediate_directive)
<< getOpenMPDirectiveName(DKind) << 1
<< getOpenMPClauseName(OMPC_depend);
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 3fc2925..267003b 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -29,17 +29,14 @@
/// Parse a standalone statement (for instance, as the body of an 'if',
/// 'while', or 'for').
StmtResult Parser::ParseStatement(SourceLocation *TrailingElseLoc,
- bool AllowOpenMPStandalone) {
+ ParsedStmtContext StmtCtx) {
StmtResult Res;
// We may get back a null statement if we found a #pragma. Keep going until
// we get an actual statement.
do {
StmtVector Stmts;
- Res = ParseStatementOrDeclaration(
- Stmts, AllowOpenMPStandalone ? ACK_StatementsOpenMPAnyExecutable
- : ACK_StatementsOpenMPNonStandalone,
- TrailingElseLoc);
+ Res = ParseStatementOrDeclaration(Stmts, StmtCtx, TrailingElseLoc);
} while (!Res.isInvalid() && !Res.get());
return Res;
@@ -96,7 +93,7 @@
///
StmtResult
Parser::ParseStatementOrDeclaration(StmtVector &Stmts,
- AllowedConstructsKind Allowed,
+ ParsedStmtContext StmtCtx,
SourceLocation *TrailingElseLoc) {
ParenBraceBracketBalancer BalancerRAIIObj(*this);
@@ -107,7 +104,7 @@
return StmtError();
StmtResult Res = ParseStatementOrDeclarationAfterAttributes(
- Stmts, Allowed, TrailingElseLoc, Attrs);
+ Stmts, StmtCtx, TrailingElseLoc, Attrs);
assert((Attrs.empty() || Res.isInvalid() || Res.isUsable()) &&
"attributes on empty statement");
@@ -147,10 +144,9 @@
};
}
-StmtResult
-Parser::ParseStatementOrDeclarationAfterAttributes(StmtVector &Stmts,
- AllowedConstructsKind Allowed, SourceLocation *TrailingElseLoc,
- ParsedAttributesWithRange &Attrs) {
+StmtResult Parser::ParseStatementOrDeclarationAfterAttributes(
+ StmtVector &Stmts, ParsedStmtContext StmtCtx,
+ SourceLocation *TrailingElseLoc, ParsedAttributesWithRange &Attrs) {
const char *SemiError = nullptr;
StmtResult Res;
@@ -165,7 +161,7 @@
{
ProhibitAttributes(Attrs); // TODO: is it correct?
AtLoc = ConsumeToken(); // consume @
- return ParseObjCAtStatement(AtLoc);
+ return ParseObjCAtStatement(AtLoc, StmtCtx);
}
case tok::code_completion:
@@ -177,7 +173,7 @@
Token Next = NextToken();
if (Next.is(tok::colon)) { // C99 6.8.1: labeled-statement
// identifier ':' statement
- return ParseLabeledStatement(Attrs);
+ return ParseLabeledStatement(Attrs, StmtCtx);
}
// Look up the identifier, and typo-correct it to a keyword if it's not
@@ -207,7 +203,8 @@
default: {
if ((getLangOpts().CPlusPlus || getLangOpts().MicrosoftExt ||
- Allowed == ACK_Any) &&
+ (StmtCtx & ParsedStmtContext::AllowDeclarationsInC) !=
+ ParsedStmtContext()) &&
isDeclarationStatement()) {
SourceLocation DeclStart = Tok.getLocation(), DeclEnd;
DeclGroupPtrTy Decl = ParseDeclaration(DeclaratorContext::BlockContext,
@@ -220,13 +217,13 @@
return StmtError();
}
- return ParseExprStatement();
+ return ParseExprStatement(StmtCtx);
}
case tok::kw_case: // C99 6.8.1: labeled-statement
- return ParseCaseStatement();
+ return ParseCaseStatement(StmtCtx);
case tok::kw_default: // C99 6.8.1: labeled-statement
- return ParseDefaultStatement();
+ return ParseDefaultStatement(StmtCtx);
case tok::l_brace: // C99 6.8.2: compound-statement
return ParseCompoundStatement();
@@ -363,7 +360,7 @@
case tok::annot_pragma_openmp:
ProhibitAttributes(Attrs);
- return ParseOpenMPDeclarativeOrExecutableDirective(Allowed);
+ return ParseOpenMPDeclarativeOrExecutableDirective(StmtCtx);
case tok::annot_pragma_ms_pointers_to_members:
ProhibitAttributes(Attrs);
@@ -382,7 +379,7 @@
case tok::annot_pragma_loop_hint:
ProhibitAttributes(Attrs);
- return ParsePragmaLoopHint(Stmts, Allowed, TrailingElseLoc, Attrs);
+ return ParsePragmaLoopHint(Stmts, StmtCtx, TrailingElseLoc, Attrs);
case tok::annot_pragma_dump:
HandlePragmaDump();
@@ -407,7 +404,7 @@
}
/// Parse an expression statement.
-StmtResult Parser::ParseExprStatement() {
+StmtResult Parser::ParseExprStatement(ParsedStmtContext StmtCtx) {
// If a case keyword is missing, this is where it should be inserted.
Token OldToken = Tok;
@@ -433,12 +430,12 @@
<< FixItHint::CreateInsertion(OldToken.getLocation(), "case ");
// Recover parsing as a case statement.
- return ParseCaseStatement(/*MissingCase=*/true, Expr);
+ return ParseCaseStatement(StmtCtx, /*MissingCase=*/true, Expr);
}
// Otherwise, eat the semicolon.
ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
- return Actions.ActOnExprStmt(Expr, isExprValueDiscarded());
+ return handleExprStmt(Expr, StmtCtx);
}
/// ParseSEHTryBlockCommon
@@ -577,10 +574,15 @@
/// identifier ':' statement
/// [GNU] identifier ':' attributes[opt] statement
///
-StmtResult Parser::ParseLabeledStatement(ParsedAttributesWithRange &attrs) {
+StmtResult Parser::ParseLabeledStatement(ParsedAttributesWithRange &attrs,
+ ParsedStmtContext StmtCtx) {
assert(Tok.is(tok::identifier) && Tok.getIdentifierInfo() &&
"Not an identifier!");
+ // The substatement is always a 'statement', not a 'declaration', but is
+ // otherwise in the same context as the labeled-statement.
+ StmtCtx &= ~ParsedStmtContext::AllowDeclarationsInC;
+
Token IdentTok = Tok; // Save the whole token.
ConsumeToken(); // eat the identifier.
@@ -610,9 +612,8 @@
// statement, but that doesn't work correctly (because ProhibitAttributes
// can't handle GNU attributes), so only call it in the one case where
// GNU attributes are allowed.
- SubStmt = ParseStatementOrDeclarationAfterAttributes(
- Stmts, /*Allowed=*/ACK_StatementsOpenMPNonStandalone, nullptr,
- TempAttrs);
+ SubStmt = ParseStatementOrDeclarationAfterAttributes(Stmts, StmtCtx,
+ nullptr, TempAttrs);
if (!TempAttrs.empty() && !SubStmt.isInvalid())
SubStmt = Actions.ProcessStmtAttributes(SubStmt.get(), TempAttrs,
TempAttrs.Range);
@@ -623,7 +624,7 @@
// If we've not parsed a statement yet, parse one now.
if (!SubStmt.isInvalid() && !SubStmt.isUsable())
- SubStmt = ParseStatement();
+ SubStmt = ParseStatement(nullptr, StmtCtx);
// Broken substmt shouldn't prevent the label from being added to the AST.
if (SubStmt.isInvalid())
@@ -643,9 +644,14 @@
/// 'case' constant-expression ':' statement
/// [GNU] 'case' constant-expression '...' constant-expression ':' statement
///
-StmtResult Parser::ParseCaseStatement(bool MissingCase, ExprResult Expr) {
+StmtResult Parser::ParseCaseStatement(ParsedStmtContext StmtCtx,
+ bool MissingCase, ExprResult Expr) {
assert((MissingCase || Tok.is(tok::kw_case)) && "Not a case stmt!");
+ // The substatement is always a 'statement', not a 'declaration', but is
+ // otherwise in the same context as the labeled-statement.
+ StmtCtx &= ~ParsedStmtContext::AllowDeclarationsInC;
+
// It is very very common for code to contain many case statements recursively
// nested, as in (but usually without indentation):
// case 1:
@@ -737,8 +743,7 @@
// continue parsing the sub-stmt.
if (Case.isInvalid()) {
if (TopLevelCase.isInvalid()) // No parsed case stmts.
- return ParseStatement(/*TrailingElseLoc=*/nullptr,
- /*AllowOpenMPStandalone=*/true);
+ return ParseStatement(/*TrailingElseLoc=*/nullptr, StmtCtx);
// Otherwise, just don't add it as a nested case.
} else {
// If this is the first case statement we parsed, it becomes TopLevelCase.
@@ -758,8 +763,7 @@
StmtResult SubStmt;
if (Tok.isNot(tok::r_brace)) {
- SubStmt = ParseStatement(/*TrailingElseLoc=*/nullptr,
- /*AllowOpenMPStandalone=*/true);
+ SubStmt = ParseStatement(/*TrailingElseLoc=*/nullptr, StmtCtx);
} else {
// Nicely diagnose the common error "switch (X) { case 4: }", which is
// not valid. If ColonLoc doesn't point to a valid text location, there was
@@ -789,8 +793,13 @@
/// 'default' ':' statement
/// Note that this does not parse the 'statement' at the end.
///
-StmtResult Parser::ParseDefaultStatement() {
+StmtResult Parser::ParseDefaultStatement(ParsedStmtContext StmtCtx) {
assert(Tok.is(tok::kw_default) && "Not a default stmt!");
+
+ // The substatement is always a 'statement', not a 'declaration', but is
+ // otherwise in the same context as the labeled-statement.
+ StmtCtx &= ~ParsedStmtContext::AllowDeclarationsInC;
+
SourceLocation DefaultLoc = ConsumeToken(); // eat the 'default'.
SourceLocation ColonLoc;
@@ -811,8 +820,7 @@
StmtResult SubStmt;
if (Tok.isNot(tok::r_brace)) {
- SubStmt = ParseStatement(/*TrailingElseLoc=*/nullptr,
- /*AllowOpenMPStandalone=*/true);
+ SubStmt = ParseStatement(/*TrailingElseLoc=*/nullptr, StmtCtx);
} else {
// Diagnose the common error "switch (X) {... default: }", which is
// not valid.
@@ -943,7 +951,8 @@
EndLoc = Tok.getLocation();
// Don't just ConsumeToken() this tok::semi, do store it in AST.
- StmtResult R = ParseStatementOrDeclaration(Stmts, ACK_Any);
+ StmtResult R =
+ ParseStatementOrDeclaration(Stmts, ParsedStmtContext::SubStmt);
if (R.isUsable())
Stmts.push_back(R.get());
}
@@ -957,14 +966,18 @@
return true;
}
-bool Parser::isExprValueDiscarded() {
- if (Actions.isCurCompoundStmtAStmtExpr()) {
- // Look to see if the next two tokens close the statement expression;
+StmtResult Parser::handleExprStmt(ExprResult E, ParsedStmtContext StmtCtx) {
+ bool IsStmtExprResult = false;
+ if ((StmtCtx & ParsedStmtContext::InStmtExpr) != ParsedStmtContext()) {
+ // Look ahead to see if the next two tokens close the statement expression;
// if so, this expression statement is the last statement in a
// statment expression.
- return Tok.isNot(tok::r_brace) || NextToken().isNot(tok::r_paren);
+ IsStmtExprResult = Tok.is(tok::r_brace) && NextToken().is(tok::r_paren);
}
- return true;
+
+ if (IsStmtExprResult)
+ E = Actions.ActOnStmtExprResult(E);
+ return Actions.ActOnExprStmt(E, /*DiscardedValue=*/!IsStmtExprResult);
}
/// ParseCompoundStatementBody - Parse a sequence of statements and invoke the
@@ -1022,6 +1035,10 @@
Stmts.push_back(R.get());
}
+ ParsedStmtContext SubStmtCtx =
+ ParsedStmtContext::Compound |
+ (isStmtExpr ? ParsedStmtContext::InStmtExpr : ParsedStmtContext());
+
while (!tryParseMisplacedModuleImport() && Tok.isNot(tok::r_brace) &&
Tok.isNot(tok::eof)) {
if (Tok.is(tok::annot_pragma_unused)) {
@@ -1034,7 +1051,7 @@
StmtResult R;
if (Tok.isNot(tok::kw___extension__)) {
- R = ParseStatementOrDeclaration(Stmts, ACK_Any);
+ R = ParseStatementOrDeclaration(Stmts, SubStmtCtx);
} else {
// __extension__ can start declarations and it can also be a unary
// operator for expressions. Consume multiple __extension__ markers here
@@ -1067,11 +1084,12 @@
continue;
}
- // FIXME: Use attributes?
// Eat the semicolon at the end of stmt and convert the expr into a
// statement.
ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
- R = Actions.ActOnExprStmt(Res, isExprValueDiscarded());
+ R = handleExprStmt(Res, SubStmtCtx);
+ if (R.isUsable())
+ R = Actions.ProcessStmtAttributes(R.get(), attrs, attrs.Range);
}
}
@@ -2001,7 +2019,7 @@
}
StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts,
- AllowedConstructsKind Allowed,
+ ParsedStmtContext StmtCtx,
SourceLocation *TrailingElseLoc,
ParsedAttributesWithRange &Attrs) {
// Create temporary attribute list.
@@ -2024,7 +2042,7 @@
MaybeParseCXX11Attributes(Attrs);
StmtResult S = ParseStatementOrDeclarationAfterAttributes(
- Stmts, Allowed, TrailingElseLoc, Attrs);
+ Stmts, StmtCtx, TrailingElseLoc, Attrs);
Attrs.takeAllFrom(TempAttrs);
return S;
@@ -2329,7 +2347,8 @@
// Condition is true, parse the statements.
while (Tok.isNot(tok::r_brace)) {
- StmtResult R = ParseStatementOrDeclaration(Stmts, ACK_Any);
+ StmtResult R =
+ ParseStatementOrDeclaration(Stmts, ParsedStmtContext::Compound);
if (R.isUsable())
Stmts.push_back(R.get());
}
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index b992f33..00b4cdd 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -13301,29 +13301,6 @@
Context.getPointerType(Context.VoidTy));
}
-/// Given the last statement in a statement-expression, check whether
-/// the result is a producing expression (like a call to an
-/// ns_returns_retained function) and, if so, rebuild it to hoist the
-/// release out of the full-expression. Otherwise, return null.
-/// Cannot fail.
-static Expr *maybeRebuildARCConsumingStmt(Stmt *Statement) {
- // Should always be wrapped with one of these.
- ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(Statement);
- if (!cleanups) return nullptr;
-
- ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(cleanups->getSubExpr());
- if (!cast || cast->getCastKind() != CK_ARCConsumeObject)
- return nullptr;
-
- // Splice out the cast. This shouldn't modify any interesting
- // features of the statement.
- Expr *producer = cast->getSubExpr();
- assert(producer->getType() == cast->getType());
- assert(producer->getValueKind() == cast->getValueKind());
- cleanups->setSubExpr(producer);
- return cleanups;
-}
-
void Sema::ActOnStartStmtExpr() {
PushExpressionEvaluationContext(ExprEvalContexts.back().Context);
}
@@ -13357,47 +13334,10 @@
QualType Ty = Context.VoidTy;
bool StmtExprMayBindToTemp = false;
if (!Compound->body_empty()) {
- Stmt *LastStmt = Compound->body_back();
- LabelStmt *LastLabelStmt = nullptr;
- // If LastStmt is a label, skip down through into the body.
- while (LabelStmt *Label = dyn_cast<LabelStmt>(LastStmt)) {
- LastLabelStmt = Label;
- LastStmt = Label->getSubStmt();
- }
-
- if (Expr *LastE = dyn_cast<Expr>(LastStmt)) {
- // Do function/array conversion on the last expression, but not
- // lvalue-to-rvalue. However, initialize an unqualified type.
- ExprResult LastExpr = DefaultFunctionArrayConversion(LastE);
- if (LastExpr.isInvalid())
- return ExprError();
- Ty = LastExpr.get()->getType().getUnqualifiedType();
-
- if (!Ty->isDependentType() && !LastExpr.get()->isTypeDependent()) {
- // In ARC, if the final expression ends in a consume, splice
- // the consume out and bind it later. In the alternate case
- // (when dealing with a retainable type), the result
- // initialization will create a produce. In both cases the
- // result will be +1, and we'll need to balance that out with
- // a bind.
- if (Expr *rebuiltLastStmt
- = maybeRebuildARCConsumingStmt(LastExpr.get())) {
- LastExpr = rebuiltLastStmt;
- } else {
- LastExpr = PerformCopyInitialization(
- InitializedEntity::InitializeStmtExprResult(LPLoc, Ty),
- SourceLocation(), LastExpr);
- }
-
- if (LastExpr.isInvalid())
- return ExprError();
- if (LastExpr.get() != nullptr) {
- if (!LastLabelStmt)
- Compound->setLastStmt(LastExpr.get());
- else
- LastLabelStmt->setSubStmt(LastExpr.get());
- StmtExprMayBindToTemp = true;
- }
+ if (const auto *LastStmt = dyn_cast<ValueStmt>(Compound->body_back())) {
+ if (const Expr *Value = LastStmt->getExprStmt()) {
+ StmtExprMayBindToTemp = true;
+ Ty = Value->getType();
}
}
}
@@ -13410,6 +13350,37 @@
return ResStmtExpr;
}
+ExprResult Sema::ActOnStmtExprResult(ExprResult ER) {
+ if (ER.isInvalid())
+ return ExprError();
+
+ // Do function/array conversion on the last expression, but not
+ // lvalue-to-rvalue. However, initialize an unqualified type.
+ ER = DefaultFunctionArrayConversion(ER.get());
+ if (ER.isInvalid())
+ return ExprError();
+ Expr *E = ER.get();
+
+ if (E->isTypeDependent())
+ return E;
+
+ // In ARC, if the final expression ends in a consume, splice
+ // the consume out and bind it later. In the alternate case
+ // (when dealing with a retainable type), the result
+ // initialization will create a produce. In both cases the
+ // result will be +1, and we'll need to balance that out with
+ // a bind.
+ auto *Cast = dyn_cast<ImplicitCastExpr>(E);
+ if (Cast && Cast->getCastKind() == CK_ARCConsumeObject)
+ return Cast->getSubExpr();
+
+ // FIXME: Provide a better location for the initialization.
+ return PerformCopyInitialization(
+ InitializedEntity::InitializeStmtExprResult(
+ E->getBeginLoc(), E->getType().getUnqualifiedType()),
+ SourceLocation(), E);
+}
+
ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
TypeSourceInfo *TInfo,
ArrayRef<OffsetOfComponent> Components,
@@ -14490,14 +14461,6 @@
// Make sure we redo semantic analysis
bool AlwaysRebuild() { return true; }
- // Make sure we handle LabelStmts correctly.
- // FIXME: This does the right thing, but maybe we need a more general
- // fix to TreeTransform?
- StmtResult TransformLabelStmt(LabelStmt *S) {
- S->getDecl()->setStmt(nullptr);
- return BaseTransform::TransformLabelStmt(S);
- }
-
// We need to special-case DeclRefExprs referring to FieldDecls which
// are not part of a member pointer formation; normal TreeTransforming
// doesn't catch this case because of the way we represent them in the AST.
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index e4b4357..5f04139 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -346,10 +346,6 @@
return getCurFunction()->CompoundScopes.back();
}
-bool Sema::isCurCompoundStmtAStmtExpr() const {
- return getCurCompoundScope().IsStmtExpr;
-}
-
StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
ArrayRef<Stmt *> Elts, bool isStmtExpr) {
const unsigned NumElts = Elts.size();
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index e411a2a..ff33028 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -318,6 +318,13 @@
TypeSourceInfo *TransformTypeWithDeducedTST(TypeSourceInfo *DI);
/// @}
+ /// The reason why the value of a statement is not discarded, if any.
+ enum StmtDiscardKind {
+ SDK_Discarded,
+ SDK_NotDiscarded,
+ SDK_StmtExprResult,
+ };
+
/// Transform the given statement.
///
/// By default, this routine transforms a statement by delegating to the
@@ -327,7 +334,7 @@
/// other mechanism.
///
/// \returns the transformed statement.
- StmtResult TransformStmt(Stmt *S, bool DiscardedValue = false);
+ StmtResult TransformStmt(Stmt *S, StmtDiscardKind SDK = SDK_Discarded);
/// Transform the given statement.
///
@@ -672,6 +679,9 @@
#define STMT(Node, Parent) \
LLVM_ATTRIBUTE_NOINLINE \
StmtResult Transform##Node(Node *S);
+#define VALUESTMT(Node, Parent) \
+ LLVM_ATTRIBUTE_NOINLINE \
+ StmtResult Transform##Node(Node *S, StmtDiscardKind SDK);
#define EXPR(Node, Parent) \
LLVM_ATTRIBUTE_NOINLINE \
ExprResult Transform##Node(Node *E);
@@ -3270,7 +3280,7 @@
};
template <typename Derived>
-StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S, bool DiscardedValue) {
+StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S, StmtDiscardKind SDK) {
if (!S)
return S;
@@ -3278,8 +3288,12 @@
case Stmt::NoStmtClass: break;
// Transform individual statement nodes
+ // Pass SDK into statements that can produce a value
#define STMT(Node, Parent) \
case Stmt::Node##Class: return getDerived().Transform##Node(cast<Node>(S));
+#define VALUESTMT(Node, Parent) \
+ case Stmt::Node##Class: \
+ return getDerived().Transform##Node(cast<Node>(S), SDK);
#define ABSTRACT_STMT(Node)
#define EXPR(Node, Parent)
#include "clang/AST/StmtNodes.inc"
@@ -3291,10 +3305,10 @@
#include "clang/AST/StmtNodes.inc"
{
ExprResult E = getDerived().TransformExpr(cast<Expr>(S));
- if (E.isInvalid())
- return StmtError();
- return getSema().ActOnExprStmt(E, DiscardedValue);
+ if (SDK == SDK_StmtExprResult)
+ E = getSema().ActOnStmtExprResult(E);
+ return getSema().ActOnExprStmt(E, SDK == SDK_Discarded);
}
}
@@ -6522,8 +6536,9 @@
bool SubStmtChanged = false;
SmallVector<Stmt*, 8> Statements;
for (auto *B : S->body()) {
- StmtResult Result =
- getDerived().TransformStmt(B, !IsStmtExpr || B != S->body_back());
+ StmtResult Result = getDerived().TransformStmt(
+ B,
+ IsStmtExpr && B == S->body_back() ? SDK_StmtExprResult : SDK_Discarded);
if (Result.isInvalid()) {
// Immediately fail if this was a DeclStmt, since it's very
@@ -6586,7 +6601,8 @@
return StmtError();
// Transform the statement following the case
- StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+ StmtResult SubStmt =
+ getDerived().TransformStmt(S->getSubStmt());
if (SubStmt.isInvalid())
return StmtError();
@@ -6594,11 +6610,11 @@
return getDerived().RebuildCaseStmtBody(Case.get(), SubStmt.get());
}
-template<typename Derived>
-StmtResult
-TreeTransform<Derived>::TransformDefaultStmt(DefaultStmt *S) {
+template <typename Derived>
+StmtResult TreeTransform<Derived>::TransformDefaultStmt(DefaultStmt *S) {
// Transform the statement following the default case
- StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+ StmtResult SubStmt =
+ getDerived().TransformStmt(S->getSubStmt());
if (SubStmt.isInvalid())
return StmtError();
@@ -6609,8 +6625,8 @@
template<typename Derived>
StmtResult
-TreeTransform<Derived>::TransformLabelStmt(LabelStmt *S) {
- StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+TreeTransform<Derived>::TransformLabelStmt(LabelStmt *S, StmtDiscardKind SDK) {
+ StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt(), SDK);
if (SubStmt.isInvalid())
return StmtError();
@@ -6619,6 +6635,11 @@
if (!LD)
return StmtError();
+ // If we're transforming "in-place" (we're not creating new local
+ // declarations), assume we're replacing the old label statement
+ // and clear out the reference to it.
+ if (LD == S->getDecl())
+ S->getDecl()->setStmt(nullptr);
// FIXME: Pass the real colon location in.
return getDerived().RebuildLabelStmt(S->getIdentLoc(),
@@ -6644,7 +6665,9 @@
}
template <typename Derived>
-StmtResult TreeTransform<Derived>::TransformAttributedStmt(AttributedStmt *S) {
+StmtResult
+TreeTransform<Derived>::TransformAttributedStmt(AttributedStmt *S,
+ StmtDiscardKind SDK) {
bool AttrsChanged = false;
SmallVector<const Attr *, 1> Attrs;
@@ -6655,7 +6678,7 @@
Attrs.push_back(R);
}
- StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt());
+ StmtResult SubStmt = getDerived().TransformStmt(S->getSubStmt(), SDK);
if (SubStmt.isInvalid())
return StmtError();
@@ -7360,7 +7383,8 @@
TreeTransform<Derived>::TransformObjCForCollectionStmt(
ObjCForCollectionStmt *S) {
// Transform the element statement.
- StmtResult Element = getDerived().TransformStmt(S->getElement());
+ StmtResult Element =
+ getDerived().TransformStmt(S->getElement(), SDK_NotDiscarded);
if (Element.isInvalid())
return StmtError();