r225581 - Add a new warning, -Wself-move, to Clang.
Richard Trieu
rtrieu at google.com
Fri Jan 9 22:04:18 PST 2015
Author: rtrieu
Date: Sat Jan 10 00:04:18 2015
New Revision: 225581
URL: http://llvm.org/viewvc/llvm-project?rev=225581&view=rev
Log:
Add a new warning, -Wself-move, to Clang.
-Wself-move is similiar to -Wself-assign. This warning is triggered when
a value is attempted to be moved to itself. See r221008 for a bug that
would have been caught with this warning.
Added:
cfe/trunk/test/SemaCXX/warn-self-move.cpp
Modified:
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaExpr.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=225581&r1=225580&r2=225581&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Sat Jan 10 00:04:18 2015
@@ -294,6 +294,7 @@ def BindToTemporaryCopy : DiagGroup<"bin
[CXX98CompatBindToTemporaryCopy]>;
def SelfAssignmentField : DiagGroup<"self-assign-field">;
def SelfAssignment : DiagGroup<"self-assign", [SelfAssignmentField]>;
+def SelfMove : DiagGroup<"self-move">;
def SemiBeforeMethodBody : DiagGroup<"semicolon-before-method-body">;
def Sentinel : DiagGroup<"sentinel">;
def MissingMethodReturnType : DiagGroup<"missing-method-return-type">;
@@ -586,6 +587,7 @@ def Most : DiagGroup<"most", [
Reorder,
ReturnType,
SelfAssignment,
+ SelfMove,
SizeofArrayArgument,
SizeofArrayDecay,
StringPlusInt,
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=225581&r1=225580&r2=225581&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Sat Jan 10 00:04:18 2015
@@ -4701,6 +4701,9 @@ def warn_addition_in_bitshift : Warning<
def warn_self_assignment : Warning<
"explicitly assigning value of variable of type %0 to itself">,
InGroup<SelfAssignment>, DefaultIgnore;
+def warn_self_move : Warning<
+ "explicitly moving variable of type %0 to itself">,
+ InGroup<SelfMove>, DefaultIgnore;
def warn_string_plus_int : Warning<
"adding %0 to a string does not append to the string">,
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=225581&r1=225580&r2=225581&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Sat Jan 10 00:04:18 2015
@@ -9380,6 +9380,90 @@ static inline UnaryOperatorKind ConvertT
return Opc;
}
+/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
+static void DiagnoseSelfMove(Sema &S, const Expr *LHSExpr, const Expr *RHSExpr,
+ SourceLocation OpLoc) {
+ if (!S.ActiveTemplateInstantiations.empty())
+ return;
+
+ // Strip parens and casts away.
+ LHSExpr = LHSExpr->IgnoreParenImpCasts();
+ RHSExpr = RHSExpr->IgnoreParenImpCasts();
+
+ // Check for a call expression
+ const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr);
+ if (!CE || CE->getNumArgs() != 1)
+ return;
+
+ // Check for a call to std::move
+ const FunctionDecl *FD = CE->getDirectCallee();
+ if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() ||
+ !FD->getIdentifier()->isStr("move"))
+ return;
+
+ // Get argument from std::move
+ RHSExpr = CE->getArg(0);
+
+ const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
+ const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
+
+ // Two DeclRefExpr's, check that the decls are the same.
+ if (LHSDeclRef && RHSDeclRef) {
+ if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
+ return;
+ if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
+ RHSDeclRef->getDecl()->getCanonicalDecl())
+ return;
+
+ S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+ << LHSExpr->getSourceRange()
+ << RHSExpr->getSourceRange();
+ return;
+ }
+
+ // Member variables require a different approach to check for self moves.
+ // MemberExpr's are the same if every nested MemberExpr refers to the same
+ // Decl and that the base Expr's are DeclRefExpr's with the same Decl or
+ // the base Expr's are CXXThisExpr's.
+ const Expr *LHSBase = LHSExpr;
+ const Expr *RHSBase = RHSExpr;
+ const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr);
+ const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr);
+ if (!LHSME || !RHSME)
+ return;
+
+ while (LHSME && RHSME) {
+ if (LHSME->getMemberDecl()->getCanonicalDecl() !=
+ RHSME->getMemberDecl()->getCanonicalDecl())
+ return;
+
+ LHSBase = LHSME->getBase();
+ RHSBase = RHSME->getBase();
+ LHSME = dyn_cast<MemberExpr>(LHSBase);
+ RHSME = dyn_cast<MemberExpr>(RHSBase);
+ }
+
+ LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase);
+ RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase);
+ if (LHSDeclRef && RHSDeclRef) {
+ if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
+ return;
+ if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
+ RHSDeclRef->getDecl()->getCanonicalDecl())
+ return;
+
+ S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+ << LHSExpr->getSourceRange()
+ << RHSExpr->getSourceRange();
+ return;
+ }
+
+ if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase))
+ S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+ << LHSExpr->getSourceRange()
+ << RHSExpr->getSourceRange();
+}
+
/// DiagnoseSelfAssignment - Emits a warning if a value is assigned to itself.
/// This warning is only emitted for builtin assignment operations. It is also
/// suppressed in the event of macro expansions.
@@ -9507,8 +9591,10 @@ ExprResult Sema::CreateBuiltinBinOp(Sour
VK = LHS.get()->getValueKind();
OK = LHS.get()->getObjectKind();
}
- if (!ResultTy.isNull())
+ if (!ResultTy.isNull()) {
DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
+ DiagnoseSelfMove(*this, LHS.get(), RHS.get(), OpLoc);
+ }
RecordModifiableNonNullParam(*this, LHS.get());
break;
case BO_PtrMemD:
Added: cfe/trunk/test/SemaCXX/warn-self-move.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-self-move.cpp?rev=225581&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-self-move.cpp (added)
+++ cfe/trunk/test/SemaCXX/warn-self-move.cpp Sat Jan 10 00:04:18 2015
@@ -0,0 +1,40 @@
+// RUN: %clang_cc1 -fsyntax-only -Wself-move -std=c++11 -verify %s
+
+// definitions for std::move
+namespace std {
+inline namespace foo {
+template <class T> struct remove_reference { typedef T type; };
+template <class T> struct remove_reference<T&> { typedef T type; };
+template <class T> struct remove_reference<T&&> { typedef T type; };
+
+template <class T> typename remove_reference<T>::type &&move(T &&t);
+}
+}
+
+void int_test() {
+ int x = 5;
+ x = std::move(x); // expected-warning{{explicitly moving}}
+ (x) = std::move(x); // expected-warning{{explicitly moving}}
+
+ using std::move;
+ x = move(x); // expected-warning{{explicitly moving}}
+}
+
+int global;
+void global_int_test() {
+ global = std::move(global); // expected-warning{{explicitly moving}}
+ (global) = std::move(global); // expected-warning{{explicitly moving}}
+
+ using std::move;
+ global = move(global); // expected-warning{{explicitly moving}}
+}
+
+class field_test {
+ int x;
+ field_test(field_test&& other) {
+ x = std::move(x); // expected-warning{{explicitly moving}}
+ x = std::move(other.x);
+ other.x = std::move(x);
+ other.x = std::move(other.x); // expected-warning{{explicitly moving}}
+ }
+};
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