Author: mboehme
Date: Fri Oct 14 08:23:39 2016
New Revision: 284235
URL: http://llvm.org/viewvc/llvm-project?rev=284235&view=rev
Log:
[clang-tidy] Add additional diagnostic to misc-use-after-move
Summary:
This adds a diagnostic to the misc-use-after-move check that is output when the
use happens on a later loop iteration than the move, for example:
A a;
for (int i = 0; i < 10; ++i) {
a.foo();
std::move(a);
}
This situation can be confusing to users because, in terms of source code
location, the use is above the move. This can make it look as if the warning
is a false positive, particularly if the loop is long but the use and move are
close together.
In cases like these, misc-use-after-move will now output an additional
diagnostic:
a.cpp:393:7: note: the use happens in a later loop iteration than the move
Reviewers: hokein
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25612
Modified:
clang-tools-extra/trunk/clang-tidy/misc/UseAfterMoveCheck.cpp
clang-tools-extra/trunk/test/clang-tidy/misc-use-after-move.cpp
Modified: clang-tools-extra/trunk/clang-tidy/misc/UseAfterMoveCheck.cpp
URL:
http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/misc/UseAfterMoveCheck.cpp?rev=284235&r1=284234&r2=284235&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/misc/UseAfterMoveCheck.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/misc/UseAfterMoveCheck.cpp Fri Oct 14
08:23:39 2016
@@ -562,18 +562,24 @@ void UseAfterMoveFinder::getReinits(
}
static void emitDiagnostic(const Expr *MovingCall,
- const ValueDecl *MovedVariable,
+ const DeclRefExpr *MoveArg,
const UseAfterMove &Use, ClangTidyCheck *Check,
ASTContext *Context) {
- Check->diag(Use.DeclRef->getExprLoc(), "'%0' used after it was moved")
- << MovedVariable->getName();
- Check->diag(MovingCall->getExprLoc(), "move occurred here",
- DiagnosticIDs::Note);
+ SourceLocation UseLoc = Use.DeclRef->getExprLoc();
+ SourceLocation MoveLoc = MovingCall->getExprLoc();
+
+ Check->diag(UseLoc, "'%0' used after it was moved")
+ << MoveArg->getDecl()->getName();
+ Check->diag(MoveLoc, "move occurred here", DiagnosticIDs::Note);
if (Use.EvaluationOrderUndefined) {
- Check->diag(Use.DeclRef->getExprLoc(),
+ Check->diag(UseLoc,
"the use and move are unsequenced, i.e. there is no guarantee "
"about the order in which they are evaluated",
DiagnosticIDs::Note);
+ } else if (UseLoc < MoveLoc || Use.DeclRef == MoveArg) {
+ Check->diag(UseLoc,
+ "the use happens in a later loop iteration than the move",
+ DiagnosticIDs::Note);
}
}
@@ -625,8 +631,6 @@ void UseAfterMoveCheck::check(const Matc
else
return;
- const ValueDecl *MovedVariable = Arg->getDecl();
-
// Ignore the std::move if the variable that was passed to it isn't a local
// variable.
if (!Arg->getDecl()->getDeclContext()->isFunctionOrMethod())
@@ -634,8 +638,8 @@ void UseAfterMoveCheck::check(const Matc
UseAfterMoveFinder finder(Result.Context);
UseAfterMove Use;
- if (finder.find(FunctionBody, MovingCall, MovedVariable, &Use))
- emitDiagnostic(MovingCall, MovedVariable, Use, this, Result.Context);
+ if (finder.find(FunctionBody, MovingCall, Arg->getDecl(), &Use))
+ emitDiagnostic(MovingCall, Arg, Use, this, Result.Context);
}
} // namespace misc
Modified: clang-tools-extra/trunk/test/clang-tidy/misc-use-after-move.cpp
URL:
http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/misc-use-after-move.cpp?rev=284235&r1=284234&r2=284235&view=diff
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/misc-use-after-move.cpp (original)
+++ clang-tools-extra/trunk/test/clang-tidy/misc-use-after-move.cpp Fri Oct 14
08:23:39 2016
@@ -133,6 +133,7 @@ void moveAfterMove() {
std::move(a);
// CHECK-MESSAGES: [[@LINE-1]]:17: warning: 'a' used after it was moved
// CHECK-MESSAGES: [[@LINE-2]]:7: note: move occurred here
+ // CHECK-MESSAGES: [[@LINE-3]]:17: note: the use happens in a later loop
}
}
}
@@ -391,7 +392,8 @@ void useAndMoveInLoop() {
for (int i = 0; i < 10; ++i) {
a.foo();
// CHECK-MESSAGES: [[@LINE-1]]:7: warning: 'a' used after it was moved
- // CHECK-MESSAGES: [[@LINE+1]]:7: note: move occurred here
+ // CHECK-MESSAGES: [[@LINE+2]]:7: note: move occurred here
+ // CHECK-MESSAGES: [[@LINE-3]]:7: note: the use happens in a later loop
std::move(a);
}
}
@@ -586,7 +588,7 @@ void assignments(int i) {
}
}
-// Passing the object to a function through a non-const pointer or refernce
+// Passing the object to a function through a non-const pointer or reference
// counts as a re-initialization.
void passByNonConstPointer(A *);
void passByNonConstReference(A &);
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
