Re-commit r273548, reverted in r273589, with a fix to not produce
-Wfor-loop-analysis warnings for a for-loop with a condition variable. In such
a case, the loop condition variable is modified on each iteration of the loop
by definition.
Original commit message:
Rearrange condition handling so that semantic checks on a condition variable
are performed before the other substatements of the construct are parsed,
rather than deferring them until the end. This allows better error recovery
from semantic errors in the condition, improves diagnostic order, and is a
prerequisite for C++17 constexpr if.
llvm-svn: 273600
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 7156cd2..8d5bec8 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -504,39 +504,30 @@
}
StmtResult
-Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
+Sema::ActOnIfStmt(SourceLocation IfLoc, ConditionResult Cond,
Stmt *thenStmt, SourceLocation ElseLoc,
Stmt *elseStmt) {
- ExprResult CondResult(CondVal.release());
-
- VarDecl *ConditionVar = nullptr;
- if (CondVar) {
- ConditionVar = cast<VarDecl>(CondVar);
- CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
- CondResult = ActOnFinishFullExpr(CondResult.get(), IfLoc);
- }
- Expr *ConditionExpr = CondResult.getAs<Expr>();
- if (ConditionExpr) {
-
- if (!Diags.isIgnored(diag::warn_comma_operator,
- ConditionExpr->getExprLoc()))
- CommaVisitor(*this).Visit(ConditionExpr);
-
- DiagnoseUnusedExprResult(thenStmt);
-
- if (!elseStmt) {
- DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
- diag::warn_empty_if_body);
- }
-
- DiagnoseUnusedExprResult(elseStmt);
- } else {
- // Create a dummy Expr for the condition for error recovery
- ConditionExpr = new (Context) OpaqueValueExpr(SourceLocation(),
- Context.BoolTy, VK_RValue);
+ auto CondVal = Cond.get();
+ if (Cond.isInvalid()) {
+ CondVal.first = nullptr;
+ CondVal.second = new (Context)
+ OpaqueValueExpr(SourceLocation(), Context.BoolTy, VK_RValue);
}
- return new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
+ if (!Diags.isIgnored(diag::warn_comma_operator,
+ CondVal.second->getExprLoc()))
+ CommaVisitor(*this).Visit(CondVal.second);
+
+ DiagnoseUnusedExprResult(thenStmt);
+
+ if (!elseStmt) {
+ DiagnoseEmptyStmtBody(CondVal.second->getLocEnd(), thenStmt,
+ diag::warn_empty_if_body);
+ }
+
+ DiagnoseUnusedExprResult(elseStmt);
+
+ return new (Context) IfStmt(Context, IfLoc, CondVal.first, CondVal.second,
thenStmt, ElseLoc, elseStmt);
}
@@ -599,24 +590,7 @@
return expr->getType();
}
-StmtResult
-Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
- Decl *CondVar) {
- ExprResult CondResult;
-
- VarDecl *ConditionVar = nullptr;
- if (CondVar) {
- ConditionVar = cast<VarDecl>(CondVar);
- CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
- if (CondResult.isInvalid())
- return StmtError();
-
- Cond = CondResult.get();
- }
-
- if (!Cond)
- return StmtError();
-
+ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
Expr *Cond;
@@ -664,24 +638,24 @@
}
} SwitchDiagnoser(Cond);
- CondResult =
+ ExprResult CondResult =
PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
- if (CondResult.isInvalid()) return StmtError();
- Cond = CondResult.get();
+ if (CondResult.isInvalid())
+ return ExprError();
// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
- CondResult = UsualUnaryConversions(Cond);
- if (CondResult.isInvalid()) return StmtError();
- Cond = CondResult.get();
+ return UsualUnaryConversions(CondResult.get());
+}
- CondResult = ActOnFinishFullExpr(Cond, SwitchLoc);
- if (CondResult.isInvalid())
+StmtResult
+Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, ConditionResult Cond) {
+ if (Cond.isInvalid())
return StmtError();
- Cond = CondResult.get();
getCurFunction()->setHasBranchIntoScope();
- SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
+ SwitchStmt *SS =
+ new (Context) SwitchStmt(Context, Cond.get().first, Cond.get().second);
getCurFunction()->SwitchStack.push_back(SS);
return SS;
}
@@ -1242,27 +1216,17 @@
}
}
-StmtResult
-Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
- Decl *CondVar, Stmt *Body) {
- ExprResult CondResult(Cond.release());
-
- VarDecl *ConditionVar = nullptr;
- if (CondVar) {
- ConditionVar = cast<VarDecl>(CondVar);
- CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
- CondResult = ActOnFinishFullExpr(CondResult.get(), WhileLoc);
- if (CondResult.isInvalid())
- return StmtError();
- }
- Expr *ConditionExpr = CondResult.get();
- if (!ConditionExpr)
+StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
+ Stmt *Body) {
+ if (Cond.isInvalid())
return StmtError();
- CheckBreakContinueBinding(ConditionExpr);
- if (ConditionExpr &&
- !Diags.isIgnored(diag::warn_comma_operator, ConditionExpr->getExprLoc()))
- CommaVisitor(*this).Visit(ConditionExpr);
+ auto CondVal = Cond.get();
+ CheckBreakContinueBinding(CondVal.second);
+
+ if (CondVal.second &&
+ !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
+ CommaVisitor(*this).Visit(CondVal.second);
DiagnoseUnusedExprResult(Body);
@@ -1270,7 +1234,7 @@
getCurCompoundScope().setHasEmptyLoopBodies();
return new (Context)
- WhileStmt(Context, ConditionVar, ConditionExpr, Body, WhileLoc);
+ WhileStmt(Context, CondVal.first, CondVal.second, Body, WhileLoc);
}
StmtResult
@@ -1280,7 +1244,7 @@
assert(Cond && "ActOnDoStmt(): missing expression");
CheckBreakContinueBinding(Cond);
- ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
+ ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
if (CondResult.isInvalid())
return StmtError();
Cond = CondResult.get();
@@ -1644,11 +1608,13 @@
}
}
-StmtResult
-Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
- Stmt *First, FullExprArg second, Decl *secondVar,
- FullExprArg third,
- SourceLocation RParenLoc, Stmt *Body) {
+StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+ Stmt *First, ConditionResult Second,
+ FullExprArg third, SourceLocation RParenLoc,
+ Stmt *Body) {
+ if (Second.isInvalid())
+ return StmtError();
+
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
@@ -1666,26 +1632,18 @@
}
}
- CheckBreakContinueBinding(second.get());
+ CheckBreakContinueBinding(Second.get().second);
CheckBreakContinueBinding(third.get());
- CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
+ if (!Second.get().first)
+ CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
+ Body);
CheckForRedundantIteration(*this, third.get(), Body);
- ExprResult SecondResult(second.release());
- VarDecl *ConditionVar = nullptr;
- if (secondVar) {
- ConditionVar = cast<VarDecl>(secondVar);
- SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
- SecondResult = ActOnFinishFullExpr(SecondResult.get(), ForLoc);
- if (SecondResult.isInvalid())
- return StmtError();
- }
-
- if (SecondResult.get() &&
+ if (Second.get().second &&
!Diags.isIgnored(diag::warn_comma_operator,
- SecondResult.get()->getExprLoc()))
- CommaVisitor(*this).Visit(SecondResult.get());
+ Second.get().second->getExprLoc()))
+ CommaVisitor(*this).Visit(Second.get().second);
Expr *Third = third.release().getAs<Expr>();
@@ -1696,8 +1654,9 @@
if (isa<NullStmt>(Body))
getCurCompoundScope().setHasEmptyLoopBodies();
- return new (Context) ForStmt(Context, First, SecondResult.get(), ConditionVar,
- Third, Body, ForLoc, LParenLoc, RParenLoc);
+ return new (Context)
+ ForStmt(Context, First, Second.get().second, Second.get().first, Third,
+ Body, ForLoc, LParenLoc, RParenLoc);
}
/// In an Objective C collection iteration statement:
@@ -2384,8 +2343,10 @@
// 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())
+ NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
+ if (!NotEqExpr.isInvalid())
+ NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
if (NotEqExpr.isInvalid()) {
Diag(RangeLoc, diag::note_for_range_invalid_iterator)
<< RangeLoc << 0 << BeginRangeRef.get()->getType();