================
@@ -0,0 +1,210 @@
+//===--- SwapBinaryOperands.cpp ----------------------------------*-
C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM
Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#include "ParsedAST.h"
+#include "SourceCode.h"
+#include "refactor/Tweak.h"
+#include "support/Logger.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/OperationKinds.h"
+#include "clang/AST/Stmt.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Tooling/Core/Replacement.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Error.h"
+
+namespace clang {
+namespace clangd {
+namespace {
+/// Check whether it makes logical sense to swap operands to an operator.
+/// Assignment or member access operators are rarely swappable
+/// while keeping the meaning intact, whereas comparison operators,
mathematical
+/// operators, etc. are often desired to be swappable for readability, avoiding
+/// bugs by assigning to nullptr when comparison was desired, etc.
+auto isOpSwappable(const BinaryOperatorKind Opcode) -> bool {
+ switch (Opcode) {
+ case BinaryOperatorKind::BO_Mul:
+ case BinaryOperatorKind::BO_Add:
+ case BinaryOperatorKind::BO_Cmp:
+ case BinaryOperatorKind::BO_LT:
+ case BinaryOperatorKind::BO_GT:
+ case BinaryOperatorKind::BO_LE:
+ case BinaryOperatorKind::BO_GE:
+ case BinaryOperatorKind::BO_EQ:
+ case BinaryOperatorKind::BO_NE:
+ case BinaryOperatorKind::BO_And:
+ case BinaryOperatorKind::BO_Xor:
+ case BinaryOperatorKind::BO_Or:
+ case BinaryOperatorKind::BO_LAnd:
+ case BinaryOperatorKind::BO_LOr:
+ case BinaryOperatorKind::BO_Comma:
+ return true;
+ // Noncommutative operators:
+ case BinaryOperatorKind::BO_Div:
+ case BinaryOperatorKind::BO_Sub:
+ case BinaryOperatorKind::BO_Shl:
+ case BinaryOperatorKind::BO_Shr:
+ case BinaryOperatorKind::BO_Rem:
+ // Member access:
+ case BinaryOperatorKind::BO_PtrMemD:
+ case BinaryOperatorKind::BO_PtrMemI:
+ // Assignment:
+ case BinaryOperatorKind::BO_Assign:
+ case BinaryOperatorKind::BO_MulAssign:
+ case BinaryOperatorKind::BO_DivAssign:
+ case BinaryOperatorKind::BO_RemAssign:
+ case BinaryOperatorKind::BO_AddAssign:
+ case BinaryOperatorKind::BO_SubAssign:
+ case BinaryOperatorKind::BO_ShlAssign:
+ case BinaryOperatorKind::BO_ShrAssign:
+ case BinaryOperatorKind::BO_AndAssign:
+ case BinaryOperatorKind::BO_XorAssign:
+ case BinaryOperatorKind::BO_OrAssign:
+ return false;
+ }
+ return false;
+}
+
+/// Some operators are asymmetric and need to be flipped when swapping their
+/// operands
+/// @param[out] Opcode the opcode to potentially swap
+/// If the opcode does not need to be swapped or is not swappable, does nothing
+void swapOperator(BinaryOperatorKind &Opcode) {
+ switch (Opcode) {
+ case BinaryOperatorKind::BO_LT:
+ Opcode = BinaryOperatorKind::BO_GT;
+ return;
+ case BinaryOperatorKind::BO_GT:
+ Opcode = BinaryOperatorKind::BO_LT;
+ return;
+ case BinaryOperatorKind::BO_LE:
+ Opcode = BinaryOperatorKind::BO_GE;
+ return;
+ case BinaryOperatorKind::BO_GE:
+ Opcode = BinaryOperatorKind::BO_LE;
+ return;
+ case BinaryOperatorKind::BO_Mul:
+ case BinaryOperatorKind::BO_Add:
+ case BinaryOperatorKind::BO_Cmp:
+ case BinaryOperatorKind::BO_EQ:
+ case BinaryOperatorKind::BO_NE:
+ case BinaryOperatorKind::BO_And:
+ case BinaryOperatorKind::BO_Xor:
+ case BinaryOperatorKind::BO_Or:
+ case BinaryOperatorKind::BO_LAnd:
+ case BinaryOperatorKind::BO_LOr:
+ case BinaryOperatorKind::BO_Comma:
+ case BinaryOperatorKind::BO_Div:
+ case BinaryOperatorKind::BO_Sub:
+ case BinaryOperatorKind::BO_Shl:
+ case BinaryOperatorKind::BO_Shr:
+ case BinaryOperatorKind::BO_Rem:
+ case BinaryOperatorKind::BO_PtrMemD:
+ case BinaryOperatorKind::BO_PtrMemI:
+ case BinaryOperatorKind::BO_Assign:
+ case BinaryOperatorKind::BO_MulAssign:
+ case BinaryOperatorKind::BO_DivAssign:
+ case BinaryOperatorKind::BO_RemAssign:
+ case BinaryOperatorKind::BO_AddAssign:
+ case BinaryOperatorKind::BO_SubAssign:
+ case BinaryOperatorKind::BO_ShlAssign:
+ case BinaryOperatorKind::BO_ShrAssign:
+ case BinaryOperatorKind::BO_AndAssign:
+ case BinaryOperatorKind::BO_XorAssign:
+ case BinaryOperatorKind::BO_OrAssign:
+ return;
+ }
+}
+
+/// Swaps the operands to a binary operator
+/// Before:
+/// x != nullptr
+/// ^ ^^^^^^^
+/// After:
+/// nullptr != x
+class SwapBinaryOperands : public Tweak {
+public:
+ const char *id() const final;
+
+ bool prepare(const Selection &Inputs) override;
+ Expected<Effect> apply(const Selection &Inputs) override;
+ std::string title() const override {
+ return llvm::formatv("Swap operands to {0}",
+ Op ? Op->getOpcodeStr() : "binary operator");
+ }
+ llvm::StringLiteral kind() const override {
+ return CodeAction::REFACTOR_KIND;
+ }
+ bool hidden() const override { return false; }
+
+private:
+ const BinaryOperator *Op;
+};
+
+REGISTER_TWEAK(SwapBinaryOperands)
+
+bool SwapBinaryOperands::prepare(const Selection &Inputs) {
+ for (const SelectionTree::Node *N = Inputs.ASTSelection.commonAncestor();
+ N && !Op; N = N->Parent) {
+ // Stop once we hit a block, e.g. a lambda in the if condition.
+ if (llvm::isa_and_nonnull<CompoundStmt>(N->ASTNode.get<Stmt>()))
+ return false;
----------------
5chmidti wrote:
IMO this can stay (with an updated comment), it makes sure that the selection
point is in the 'scope' of the binary operator, not from somewhere inside a
lambda for example (`5 < [](){ ^return 1; }`)
https://github.com/llvm/llvm-project/pull/78999
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