shuaiwang created this revision.
shuaiwang added reviewers: lebedev.ri, JonasToth.
Herald added subscribers: cfe-commits, Szelethus, mikhail.ramalho, a.sidorin,
szepet, xazax.hun.
Herald added a reviewer: george.karpenkov.
This is a follow up of https://reviews.llvm.org/D52008 and should make the
analyzer being able to handle perfect forwardings in real world cases where
forwardings are done through multiple layers of function calls with
`std::forward`.
Fixes PR38891.
Repository:
rC Clang
https://reviews.llvm.org/D52120
Files:
lib/Analysis/ExprMutationAnalyzer.cpp
unittests/Analysis/ExprMutationAnalyzerTest.cpp
Index: unittests/Analysis/ExprMutationAnalyzerTest.cpp
===================================================================
--- unittests/Analysis/ExprMutationAnalyzerTest.cpp
+++ unittests/Analysis/ExprMutationAnalyzerTest.cpp
@@ -373,36 +373,46 @@
}
TEST(ExprMutationAnalyzerTest, Move) {
- // Technically almost the same as ByNonConstRRefArgument, just double checking
- const auto AST = tooling::buildASTFromCode(
+ const std::string Move =
"namespace std {"
"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 std::remove_reference<T>::type&& "
- "move(T&& t) noexcept; }"
- "void f() { struct A {}; A x; std::move(x); }");
- const auto Results =
+ "move(T&& t) noexcept {} }";
+ auto AST = tooling::buildASTFromCode(
+ Move + "void f() { struct A {}; A x; std::move(x); }");
+ auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("std::move(x)"));
+ EXPECT_FALSE(isMutated(Results, AST.get()));
+
+ AST = tooling::buildASTFromCode(
+ Move + "void f() { struct A {}; A x, y; std::move(x) = y; }");
+ Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("std::move(x) = y"));
}
TEST(ExprMutationAnalyzerTest, Forward) {
- // Technically almost the same as ByNonConstRefArgument, just double checking
- const auto AST = tooling::buildASTFromCode(
+ const std::string Forward =
"namespace std {"
"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> T&& "
- "forward(typename std::remove_reference<T>::type&) noexcept;"
+ "forward(typename std::remove_reference<T>::type&) noexcept {}"
"template<class T> T&& "
- "forward(typename std::remove_reference<T>::type&&) noexcept;"
- "void f() { struct A {}; A x; std::forward<A &>(x); }");
- const auto Results =
+ "forward(typename std::remove_reference<T>::type&&) noexcept {} }";
+ auto AST = tooling::buildASTFromCode(
+ Forward + "void f() { struct A {}; A x; std::forward<A &>(x); }");
+ auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_FALSE(isMutated(Results, AST.get()));
+
+ AST = tooling::buildASTFromCode(
+ Forward + "void f() { struct A {}; A x, y; std::forward<A &>(x) = y; }");
+ Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()),
- ElementsAre("std::forward<A &>(x)"));
+ ElementsAre("std::forward<A &>(x) = y"));
}
TEST(ExprMutationAnalyzerTest, CallUnresolved) {
@@ -639,6 +649,26 @@
"void f() { int x; S s(x); }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("x"));
+
+ AST = tooling::buildASTFromCode(
+ "namespace std {"
+ "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> T&& "
+ "forward(typename std::remove_reference<T>::type& t) noexcept"
+ "{ return t; }"
+ "template<class T> T&& "
+ "forward(typename std::remove_reference<T>::type&& t) noexcept"
+ "{ return t; } }"
+ "template <class... Args> void u(Args&...);"
+ "template <class... Args> void h(Args&&... args)"
+ "{ u(std::forward<Args>(args)...); }"
+ "template <class... Args> void g(Args&&... args)"
+ "{ h(std::forward<Args>(args)...); }"
+ "void f() { int x; g(x); }");
+ Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("g(x)"));
}
TEST(ExprMutationAnalyzerTest, FollowFuncArgNotModified) {
@@ -683,6 +713,26 @@
"void f() { int x; S s(x); }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_FALSE(isMutated(Results, AST.get()));
+
+ AST = tooling::buildASTFromCode(
+ "namespace std {"
+ "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> T&& "
+ "forward(typename std::remove_reference<T>::type& t) noexcept"
+ "{ return t; }"
+ "template<class T> T&& "
+ "forward(typename std::remove_reference<T>::type&& t) noexcept"
+ "{ return t; } }"
+ "template <class... Args> void u(Args...);"
+ "template <class... Args> void h(Args&&... args)"
+ "{ u(std::forward<Args>(args)...); }"
+ "template <class... Args> void g(Args&&... args)"
+ "{ h(std::forward<Args>(args)...); }"
+ "void f() { int x; g(x); }");
+ Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_FALSE(isMutated(Results, AST.get()));
}
TEST(ExprMutationAnalyzerTest, ArrayElementModified) {
Index: lib/Analysis/ExprMutationAnalyzer.cpp
===================================================================
--- lib/Analysis/ExprMutationAnalyzer.cpp
+++ lib/Analysis/ExprMutationAnalyzer.cpp
@@ -261,7 +261,16 @@
nonConstReferenceType()))))
.bind("expr")),
Stm, Context);
- return findExprMutation(Casts);
+ if (const Stmt *S = findExprMutation(Casts))
+ return S;
+ // Treat std::{move,forward} as cast.
+ const auto Calls =
+ match(findAll(callExpr(callee(namedDecl(
+ hasAnyName("::std::move", "::std::forward"))),
+ hasArgument(0, equalsNode(Exp)))
+ .bind("expr")),
+ Stm, Context);
+ return findExprMutation(Calls);
}
const Stmt *ExprMutationAnalyzer::findRangeLoopMutation(const Expr *Exp) {
@@ -318,7 +327,9 @@
const auto IsInstantiated = hasDeclaration(isInstantiated());
const auto FuncDecl = hasDeclaration(functionDecl().bind("func"));
const auto Matches = match(
- findAll(expr(anyOf(callExpr(NonConstRefParam, IsInstantiated, FuncDecl),
+ findAll(expr(anyOf(callExpr(NonConstRefParam, IsInstantiated, FuncDecl,
+ unless(callee(namedDecl(hasAnyName(
+ "::std::move", "::std::forward"))))),
cxxConstructExpr(NonConstRefParam, IsInstantiated,
FuncDecl)))
.bind("expr")),
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