mboehme updated this revision to Diff 506510.
mboehme added a comment.
Added entry to release notes.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D145581/new/
https://reviews.llvm.org/D145581
Files:
clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/test/clang-tidy/checkers/bugprone/use-after-move.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/bugprone/use-after-move.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/bugprone/use-after-move.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone/use-after-move.cpp
@@ -1,3 +1,4 @@
+// RUN: %check_clang_tidy -std=c++11 -check-suffixes=,CXX11 %s bugprone-use-after-move %t -- -- -fno-delayed-template-parsing
// RUN: %check_clang_tidy -std=c++17-or-later %s bugprone-use-after-move %t -- -- -fno-delayed-template-parsing
typedef decltype(nullptr) nullptr_t;
@@ -123,6 +124,7 @@
A &operator=(A &&);
void foo() const;
+ void bar(int i) const;
int getInt() const;
operator bool() const;
@@ -1307,6 +1309,30 @@
}
}
+// In a function call, the expression that determines the callee is sequenced
+// before the arguments -- but only in C++17 and later.
+namespace CalleeSequencedBeforeArguments {
+int consumeA(std::unique_ptr<A> a);
+
+void calleeSequencedBeforeArguments() {
+ {
+ std::unique_ptr<A> a;
+ a->bar(consumeA(std::move(a)));
+ // CHECK-NOTES-CXX11: [[@LINE-1]]:5: warning: 'a' used after it was moved
+ // CHECK-NOTES-CXX11: [[@LINE-2]]:21: note: move occurred here
+ // CHECK-NOTES-CXX11: [[@LINE-3]]:5: note: the use and move are unsequenced
+ }
+ {
+ std::unique_ptr<A> a;
+ std::unique_ptr<A> getArg(std::unique_ptr<A> a);
+ getArg(std::move(a))->bar(a->getInt());
+ // CHECK-NOTES: [[@LINE-1]]:31: warning: 'a' used after it was moved
+ // CHECK-NOTES: [[@LINE-2]]:12: note: move occurred here
+ // CHECK-NOTES-CXX11: [[@LINE-3]]:31: note: the use and move are unsequenced
+ }
+}
+} // namespace CalleeSequencedBeforeArguments
+
// Some statements in templates (e.g. null, break and continue statements) may
// be shared between the uninstantiated and instantiated versions of the
// template and therefore have multiple parents. Make sure the sequencing code
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -219,9 +219,12 @@
<clang-tidy/checks/cppcoreguidelines/slicing>` check when warning would be
emitted in constructor for virtual base class initialization.
-- Improved :doc:`bugprone-use-after-move
- <clang-tidy/checks/bugprone/use-after-move>` to understand that there is a
- sequence point between designated initializers.
+- In :doc:`bugprone-use-after-move
+ <clang-tidy/checks/bugprone/use-after-move>`:
+ - Fixed handling for designated initializers.
+ - Fix: In C++17 and later, the callee of a function is guaranteed to be
+ sequenced before the arguments, so don't warn if the use happens in the
+ callee and the move happens in one of the arguments.
Removed checks
^^^^^^^^^^^^^^
Index: clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
===================================================================
--- clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
+++ clang-tools-extra/clang-tidy/utils/ExprSequence.cpp
@@ -95,9 +95,29 @@
return true;
}
+ SmallVector<const Stmt *, 1> BeforeParents = getParentStmts(Before, Context);
+
+ // Since C++17, the callee of a call expression is guaranteed to be sequenced
+ // before all of the arguments.
+ // We handle this as a special case rather than using the general
+ // `getSequenceSuccessor` logic above because the callee expression doesn't
+ // have an unambiguous successor; the order in which arguments are evaluated
+ // is indeterminate.
+ if (Context->getLangOpts().CPlusPlus17) {
+ for (const Stmt *Parent : BeforeParents) {
+ if (const auto *call = dyn_cast<CallExpr>(Parent);
+ call && call->getCallee() == Before) {
+ for (const Expr *arg : call->arguments()) {
+ if (isDescendantOrEqual(After, arg, Context))
+ return true;
+ }
+ }
+ }
+ }
+
// If 'After' is a parent of 'Before' or is sequenced after one of these
// parents, we know that it is sequenced after 'Before'.
- for (const Stmt *Parent : getParentStmts(Before, Context)) {
+ for (const Stmt *Parent : BeforeParents) {
if (Parent == After || inSequence(Parent, After))
return true;
}
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