Sockke updated this revision to Diff 365455.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D107450/new/
https://reviews.llvm.org/D107450
Files:
clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
clang-tools-extra/test/clang-tidy/checkers/performance-move-const-arg.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/performance-move-const-arg.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/performance-move-const-arg.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/performance-move-const-arg.cpp
@@ -70,7 +70,11 @@
// CHECK-FIXES: return x3;
}
-A f4(A x4) { return std::move(x4); }
+A f4(A x4) {
+ return std::move(x4);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: it's superfluous; a move will happen, with or without the std::move
+ // CHECK-FIXES: return x4;
+}
A f5(const A x5) {
return std::move(x5);
@@ -246,3 +250,82 @@
};
f(MoveSemantics());
}
+
+void showInt(int &&) {}
+int testInt() {
+ int a = 10;
+ int b = std::move(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect; remove std::move()
+ // CHECK-FIXES: int b = a;
+ showInt(std::move(a));
+ // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect; consider changing showInt's parameter from 'int'&& to 'int'&
+ return std::move(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect; remove std::move()
+ // CHECK-FIXES: return a;
+}
+template <class T>
+void forwardToShowInt(T &&t) {
+ showInt(static_cast<T &&>(t));
+}
+void testTemplate() {
+ int a = 10;
+ forwardToShowInt(std::move(a));
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: std::move of the variable 'a' of the trivially-copyable type 'int' has no effect; consider changing forwardToShowInt's parameter from 'int'&& to 'int'&
+}
+
+struct Tmp {};
+void showTmp(Tmp &&) {}
+Tmp testTmp() {
+ Tmp t;
+ Tmp t1 = std::move(t);
+ // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: std::move of the variable 't' of the trivially-copyable type 'Tmp' has no effect; remove std::move()
+ // CHECK-FIXES: Tmp t1 = t;
+ Tmp t2 = std::move(Tmp());
+ // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: std::move of the expression of the trivially-copyable type 'Tmp' has no effect; remove std::move()
+ // CHECK-FIXES: Tmp t2 = Tmp();
+ showTmp(std::move(t));
+ // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: std::move of the variable 't' of the trivially-copyable type 'Tmp' has no effect; consider changing showTmp's parameter from 'Tmp'&& to 'Tmp'&
+ return std::move(t);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable 't' of the trivially-copyable type 'Tmp' has no effect; remove std::move()
+ // CHECK-FIXES: return t;
+}
+
+struct Tmp_UnTriviallyC {
+ Tmp_UnTriviallyC() {}
+ Tmp_UnTriviallyC(const Tmp_UnTriviallyC &) {}
+};
+void showTmp_UnTriviallyC(Tmp_UnTriviallyC &&) {}
+Tmp_UnTriviallyC testTmp_UnTriviallyC() {
+ Tmp_UnTriviallyC tn;
+ Tmp_UnTriviallyC tn1 = std::move(tn);
+ // CHECK-MESSAGES: :[[@LINE-1]]:26: warning: passing result of std::move() as a const reference argument; no move will actually happen
+ // CHECK-FIXES: Tmp_UnTriviallyC tn1 = tn;
+ Tmp_UnTriviallyC tn2 = std::move(Tmp_UnTriviallyC());
+ // CHECK-MESSAGES: :[[@LINE-1]]:26: warning: passing result of std::move() as a const reference argument; no move will actually happen
+ // CHECK-FIXES: Tmp_UnTriviallyC tn2 = Tmp_UnTriviallyC();
+ showTmp_UnTriviallyC(std::move(tn));
+ // Expect no warning given here.
+ return std::move(tn);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: passing result of std::move() as a const reference argument; no move will actually happen
+ // CHECK-FIXES: return tn;
+}
+
+struct Tmp_UnTriviallyCR {
+ Tmp_UnTriviallyCR() {}
+ Tmp_UnTriviallyCR(const Tmp_UnTriviallyCR &) {}
+ Tmp_UnTriviallyCR(Tmp_UnTriviallyCR &&) {}
+};
+void showTmp_UnTriviallyCR(Tmp_UnTriviallyCR &&) {}
+Tmp_UnTriviallyCR testTmp_UnTriviallyCR() {
+ Tmp_UnTriviallyCR tnr;
+ Tmp_UnTriviallyCR tnr1 = std::move(tnr);
+ // Expect no warning given here.
+ Tmp_UnTriviallyCR tnr2 = std::move(Tmp_UnTriviallyCR());
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: it's superfluous; a move will happen, with or without the std::move
+ // CHECK-FIXES: Tmp_UnTriviallyCR tnr2 = Tmp_UnTriviallyCR();
+ showTmp_UnTriviallyCR(std::move(tnr));
+ // Expect no warning given here.
+ return std::move(tnr);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: it's superfluous; a move will happen, with or without the std::move
+ // CHECK-FIXES: return tnr;
+}
Index: clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
===================================================================
--- clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
+++ clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.h
@@ -10,6 +10,7 @@
#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MOVECONSTANTARGUMENTCHECK_H
#include "../ClangTidyCheck.h"
+#include "llvm/ADT/DenseSet.h"
namespace clang {
namespace tidy {
@@ -36,6 +37,7 @@
private:
const bool CheckTriviallyCopyableMove;
+ llvm::DenseSet<const CallExpr*> HasCheckedMoveSet;
};
} // namespace performance
Index: clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
+++ clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
@@ -47,17 +47,41 @@
Finder->addMatcher(MoveCallMatcher, this);
+ Finder->addMatcher(
+ returnStmt(
+ hasReturnValue(anyOf(
+ ignoringParenImpCasts(MoveCallMatcher),
+ cxxConstructExpr(
+ hasDeclaration(cxxConstructorDecl(
+ allOf(isUserProvided(), isMoveConstructor()))),
+ hasAnyArgument(ignoringParenImpCasts(MoveCallMatcher))))))
+ .bind("return-call-move"),
+ this);
+
Finder->addMatcher(
invocation(forEachArgumentWithParam(
MoveCallMatcher,
- parmVarDecl(hasType(references(isConstQualified())))))
+ parmVarDecl(anyOf(hasType(references(isConstQualified())),
+ hasType(rValueReferenceType())))
+ .bind("invocation-parm")))
.bind("receiving-expr"),
this);
}
void MoveConstArgCheck::check(const MatchFinder::MatchResult &Result) {
const auto *CallMove = Result.Nodes.getNodeAs<CallExpr>("call-move");
+ const auto *ReturnCallMove =
+ Result.Nodes.getNodeAs<ReturnStmt>("return-call-move");
const auto *ReceivingExpr = Result.Nodes.getNodeAs<Expr>("receiving-expr");
+ const auto *InvocationParm =
+ Result.Nodes.getNodeAs<ParmVarDecl>("invocation-parm");
+
+ if (!ReturnCallMove && !ReceivingExpr && HasCheckedMoveSet.count(CallMove))
+ return;
+
+ if (ReturnCallMove || ReceivingExpr)
+ HasCheckedMoveSet.insert(CallMove);
+
const Expr *Arg = CallMove->getArg(0);
SourceManager &SM = Result.Context->getSourceManager();
@@ -90,23 +114,51 @@
return;
bool IsVariable = isa<DeclRefExpr>(Arg);
+ bool IsInvocationArg = false;
+ StringRef FuncName;
const auto *Var =
IsVariable ? dyn_cast<DeclRefExpr>(Arg)->getDecl() : nullptr;
- auto Diag = diag(FileMoveRange.getBegin(),
- "std::move of the %select{|const }0"
- "%select{expression|variable %4}1 "
- "%select{|of the trivially-copyable type %5 }2"
- "has no effect; remove std::move()"
- "%select{| or make the variable non-const}3")
- << IsConstArg << IsVariable << IsTriviallyCopyable
- << (IsConstArg && IsVariable && !IsTriviallyCopyable) << Var
- << Arg->getType();
+ if (ReceivingExpr &&
+ InvocationParm->getOriginalType()->isRValueReferenceType() &&
+ !ReceivingExpr->getType()->isRecordType() && Arg->isLValue()) {
+ IsInvocationArg = true;
+ const auto *ReceivingCallExpr = dyn_cast<CallExpr>(ReceivingExpr);
+ if (!ReceivingCallExpr)
+ return;
+ const auto *FD = ReceivingCallExpr->getDirectCallee();
+ FuncName = FD->getName();
+ }
+ auto Diag =
+ diag(FileMoveRange.getBegin(),
+ "std::move of the %select{|const }0"
+ "%select{expression|variable %5}1 "
+ "%select{|of the trivially-copyable type %6 }2"
+ "has no effect; %select{remove std::move()|}3"
+ "%select{| or make the variable non-const}4"
+ "%select{|consider changing %7's parameter from %6&& to %6&}3")
+ << IsConstArg << IsVariable << IsTriviallyCopyable << IsInvocationArg
+ << (IsConstArg && IsVariable && !IsTriviallyCopyable &&
+ !IsInvocationArg)
+ << Var << Arg->getType() << FuncName;
+
+ if (!IsInvocationArg)
+ replaceCallWithArg(CallMove, Diag, SM, getLangOpts());
+ } else if (ReturnCallMove || ReceivingExpr) {
+ if (ReceivingExpr &&
+ InvocationParm->getOriginalType()->isRValueReferenceType() &&
+ Arg->isLValue())
+ return;
- replaceCallWithArg(CallMove, Diag, SM, getLangOpts());
- } else if (ReceivingExpr) {
- auto Diag = diag(FileMoveRange.getBegin(),
- "passing result of std::move() as a const reference "
- "argument; no move will actually happen");
+ bool IsMoveConstruct = false;
+ if (ReturnCallMove ||
+ InvocationParm->getOriginalType()->isRValueReferenceType())
+ IsMoveConstruct = true;
+ auto Diag =
+ diag(FileMoveRange.getBegin(),
+ "%select{passing result of std::move() as a const reference "
+ "argument; no move will actually happen|it's superfluous; a move "
+ "will happen, with or without the std::move}0")
+ << IsMoveConstruct;
replaceCallWithArg(CallMove, Diag, SM, getLangOpts());
}
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