SureYeaah created this revision.
SureYeaah added reviewers: sammccall, kadircet.
Herald added subscribers: cfe-commits, arphaman, jkorous, mgorny.
Herald added a project: clang.
SureYeaah retitled this revision from "dummy variable extraction on a function
scope" to "[clangd] dummy variable extraction on a function scope".
Herald added subscribers: MaskRay, ilya-biryukov.
- Added extraction to a dummy variable
- using auto for the dummy variable type for now
- Works on a function scope
- Adding braces to create a compound statement not supported yet
- added unit tests
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D63773
Files:
clang-tools-extra/clangd/refactor/tweaks/CMakeLists.txt
clang-tools-extra/clangd/refactor/tweaks/ExtractVariable.cpp
clang-tools-extra/clangd/unittests/TweakTests.cpp
Index: clang-tools-extra/clangd/unittests/TweakTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/TweakTests.cpp
+++ clang-tools-extra/clangd/unittests/TweakTests.cpp
@@ -216,6 +216,207 @@
checkTransform(ID, Input, Output);
}
+TEST(TweakTest, ExtractVariable) {
+ llvm::StringLiteral ID = "ExtractVariable";
+
+ checkAvailable(ID, R"cpp(
+ int xyz() {
+ return 1;
+ }
+ void f() {
+ int a = 5 + [[4 * [[^xyz()]]]];
+ // FIXME: add test case for multiple variable initialization once
+ // SelectionTree commonAncestor bug is fixed
+ switch(a) {
+ case 1: {
+ a = ^1;
+ break;
+ }
+ default: {
+ a = ^3;
+ }
+ }
+ if(a < ^3)
+ if(a == 4)
+ a = 5;
+ else
+ a = 6;
+ else if (a < 4) {
+ a = ^4;
+ }
+ else {
+ a = ^5;
+ }
+ // for loop testing
+ for(a = ^1; a > ^3+^4; a++)
+ a = 2;
+ // while testing
+ while(a < ^1) {
+ ^a++;
+ }
+ // do while testing
+ do
+ a = 1;
+ while(a < ^3);
+ }
+ )cpp");
+ checkNotAvailable(ID, R"cpp(
+ void f(int b = ^1) {
+ int a = 5 + 4 * 3;
+ // switch testing
+ switch(a) {
+ case 1:
+ a = ^1;
+ break;
+ default:
+ a = ^3;
+ }
+ // if testing
+ if(a < 3)
+ if(a == ^4)
+ a = ^5;
+ else
+ a = ^6;
+ else if (a < ^4) {
+ a = 4;
+ }
+ else {
+ a = 5;
+ }
+ // for loop testing
+ for(int a = 1, b = 2, c = 3; ^a > ^b ^+ ^c; ^a++)
+ a = ^2;
+ // while testing
+ while(a < 1) {
+ a++;
+ }
+ // do while testing
+ do
+ a = ^1;
+ while(a < 3);
+ // testing in cases where braces are required
+ if (true)
+ do
+ a = 1;
+ while(a < ^1);
+ }
+ )cpp");
+ // vector of pairs of input and output strings
+ const std::vector<std::pair<llvm::StringLiteral, llvm::StringLiteral>>
+ InputOutputs = {
+ // extraction from variable declaration/assignment
+ {R"cpp(void varDecl() {
+ int a = 5 * (4 + (3 [[- 1)]]);
+ })cpp",
+ R"cpp(void varDecl() {
+ auto dummy = (3 - 1); int a = 5 * (4 + dummy);
+ })cpp"},
+ // extraction from for loop init/cond/incr
+ {R"cpp(void forLoop() {
+ for(int a = 1; a < ^3; a++) {
+ a = 5 + 4 * 3;
+ }
+ })cpp",
+ R"cpp(void forLoop() {
+ auto dummy = 3; for(int a = 1; a < dummy; a++) {
+ a = 5 + 4 * 3;
+ }
+ })cpp"},
+ // extraction inside for loop body
+ {R"cpp(void forBody() {
+ for(int a = 1; a < 3; a++) {
+ a = 5 + [[4 * 3]];
+ }
+ })cpp",
+ R"cpp(void forBody() {
+ for(int a = 1; a < 3; a++) {
+ auto dummy = 4 * 3; a = 5 + dummy;
+ }
+ })cpp"},
+ // extraction inside while loop condition
+ {R"cpp(void whileLoop(int a) {
+ while(a < 5 + [[4 * 3]])
+ a += 1;
+ })cpp",
+ R"cpp(void whileLoop(int a) {
+ auto dummy = 4 * 3; while(a < 5 + dummy)
+ a += 1;
+ })cpp"},
+ // extraction inside while body condition
+ {R"cpp(void whileBody(int a) {
+ while(a < 1) {
+ a += ^7 * 3;
+ }
+ })cpp",
+ R"cpp(void whileBody(int a) {
+ while(a < 1) {
+ auto dummy = 7; a += dummy * 3;
+ }
+ })cpp"},
+ // extraction inside do-while loop condition
+ {R"cpp(void doWhileLoop(int a) {
+ do
+ a += 3;
+ while(a < ^1);
+ })cpp",
+ R"cpp(void doWhileLoop(int a) {
+ auto dummy = 1; do
+ a += 3;
+ while(a < dummy);
+ })cpp"},
+ // extraction inside do-while body
+ {R"cpp(void doWhileBody(int a) {
+ do {
+ a += ^3;
+ }
+ while(a < 1);
+ })cpp",
+ R"cpp(void doWhileBody(int a) {
+ do {
+ auto dummy = 3; a += dummy;
+ }
+ while(a < 1);
+ })cpp"},
+ // extraction inside switch condition
+ {R"cpp(void switchLoop(int a) {
+ switch(a = 1 + [[3 * 5]]) {
+ default:
+ break;
+ }
+ })cpp",
+ R"cpp(void switchLoop(int a) {
+ auto dummy = 3 * 5; switch(a = 1 + dummy) {
+ default:
+ break;
+ }
+ })cpp"},
+ // extraction inside case body
+ {R"cpp(void caseBody(int a) {
+ switch(1) {
+ case 1: {
+ a = ^1;
+ break;
+ }
+ default:
+ break;
+ }
+ })cpp",
+ R"cpp(void caseBody(int a) {
+ switch(1) {
+ case 1: {
+ auto dummy = 1; a = dummy;
+ break;
+ }
+ default:
+ break;
+ }
+ })cpp"},
+ };
+ for (const auto &IO : InputOutputs) {
+ checkTransform(ID, IO.first, IO.second);
+ }
+}
+
} // namespace
} // namespace clangd
} // namespace clang
Index: clang-tools-extra/clangd/refactor/tweaks/ExtractVariable.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clangd/refactor/tweaks/ExtractVariable.cpp
@@ -0,0 +1,193 @@
+//===--- ExtractVariable.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 "ClangdUnit.h"
+#include "Logger.h"
+#include "Protocol.h"
+#include "Selection.h"
+#include "SourceCode.h"
+#include "refactor/Tweak.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/RecursiveASTVisitor.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/None.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Error.h"
+
+namespace clang {
+namespace clangd {
+namespace {
+
+//
+/// Extracts an expression to the variable dummy
+/// Before:
+/// int x = 5 + 4 * 3;
+/// ^^^^^
+/// After:
+/// auto dummy = 5 + 4;
+/// int x = dummy * 3;
+class ExtractVariable : public Tweak {
+public:
+ const char *id() const override final;
+ bool prepare(const Selection &Inputs) override;
+ Expected<tooling::Replacements> apply(const Selection &Inputs) override;
+ std::string title() const override;
+
+private:
+ // the expression to extract
+ const clang::Expr *Exp = nullptr;
+ // the statement before which variable will be extracted to
+ const clang::Stmt *Stm = nullptr;
+};
+REGISTER_TWEAK(ExtractVariable)
+
+// RAV subclass to find all DeclRefs in a given Stmt
+class FindDeclRefsVisitor
+ : public clang::RecursiveASTVisitor<FindDeclRefsVisitor> {
+public:
+ FindDeclRefsVisitor(const SourceManager &M) : M(&M){};
+
+ // checks whether any variable in a given expr is declared in the DeclStmt
+ bool isDeclaredIn(const DeclStmt *Decl, const Expr *Exp) {
+ this->Decl = Decl;
+ // if complete traversal is unsuccessful, return true
+ return !TraverseStmt(const_cast<Stmt *>(dyn_cast<Stmt>(Exp)));
+ }
+ // Visit each DeclRefExpr and check whether it was declared in Decl
+ bool VisitDeclRefExpr(DeclRefExpr *DeclRef) { // NOLINT
+ // Beginning location of the ValueDecl of the DeclRef
+ auto ValueDeclLoc = DeclRef->getDecl()->getBeginLoc();
+ // return false if this ValueDecl location is within the DeclStmt
+ return !M->isPointWithin(ValueDeclLoc, Decl->getBeginLoc(),
+ Decl->getEndLoc());
+ }
+
+private:
+ const DeclStmt *Decl;
+ const SourceManager *M;
+};
+
+// Here T is a Stmt subclass and getBody is a member function that returns its
+// "body" Stmt.
+// Checks whether N is inside the body of Stm.
+template <typename T, const Stmt *(T::*getBody)() const>
+static bool isInBodyOf(const SelectionTree::Node *N, const Stmt *Stm,
+ const SourceManager &M) {
+ auto CastStm = dyn_cast_or_null<T>(Stm);
+ if (!CastStm)
+ return false; // return false if can't be casted
+ auto BodyRng = (CastStm->*getBody)()->getSourceRange();
+ auto NodeRng = N->ASTNode.getSourceRange();
+ return M.isPointWithin(NodeRng.getBegin(), BodyRng.getBegin(),
+ BodyRng.getEnd());
+}
+// Returns true if we will need braces after extraction
+static bool needBraces(const SelectionTree::Node *N, const Stmt *Stm,
+ const SourceManager &M) {
+ return isInBodyOf<ForStmt, &ForStmt::getBody>(N, Stm, M) ||
+ isInBodyOf<WhileStmt, &WhileStmt::getBody>(N, Stm, M) ||
+ isInBodyOf<DoStmt, &DoStmt::getBody>(N, Stm, M) ||
+ // for an if statement we have two bodies - Then and Else
+ isInBodyOf<IfStmt, &IfStmt::getThen>(N, Stm, M) ||
+ isInBodyOf<IfStmt, &IfStmt::getElse>(N, Stm, M) ||
+ isInBodyOf<CaseStmt, &CaseStmt::getSubStmt>(N, Stm, M) ||
+ isInBodyOf<DefaultStmt, &DefaultStmt::getSubStmt>(N, Stm, M);
+}
+
+// check whether to allow extraction from for(...)
+static bool checkFor(const ForStmt *F, const Expr *Exp,
+ const SourceManager &M) {
+ const Stmt *Init = F->getInit();
+ if (!Init || !isa<DeclStmt>(Init))
+ return true; // FIXME
+ FindDeclRefsVisitor Visitor(M);
+ // if any variable in Exp is declared in the DeclStmt, return false
+ return !Visitor.isDeclaredIn(dyn_cast<DeclStmt>(Init), Exp);
+}
+//
+// Return the Stmt before which we need to insert the extraction.
+static const clang::Stmt *getStmt(const SelectionTree::Node *N,
+ const SourceManager &M) {
+ auto CurN = N;
+ while (CurN->Parent) {
+ auto ParStmt = CurN->Parent->ASTNode.get<Stmt>();
+ if (!ParStmt) {
+ } else if (isa<CompoundStmt>(ParStmt)) {
+ return CurN->ASTNode.get<Stmt>();
+ } else if (needBraces(N, ParStmt, M)) {
+ // We will need more functionality here later on
+ llvm::errs() << "Need braces.\n";
+ break;
+ } else if (isa<CaseStmt>(ParStmt) &&
+ !isInBodyOf<CaseStmt, &CaseStmt::getSubStmt>(N, ParStmt, M)) {
+ // give up if it's a Case Statement constant
+ break;
+ } else if (isa<ForStmt>(ParStmt) && !checkFor(dyn_cast<ForStmt>(ParStmt),
+ N->ASTNode.get<Expr>(), M)) {
+ // Check whether the expression references any variable in the for
+ // initializer and if so, we can't extract
+ llvm::errs() << "Can't extract from for\n";
+ break;
+ }
+ CurN = CurN->Parent;
+ }
+ return nullptr;
+}
+
+// FIXME(Bug in selection tree): doesn't work for int a = 6, b = 8;
+// FIXME: case constant refactoring
+// FIXME: if, while, else, for, case, default statements without curly braces
+// and their combinations
+// FIXME: Ignore assignment (a = 1) Expr since it is extracted as dummy = a = 1
+bool ExtractVariable::prepare(const Selection &Inputs) {
+ const auto &M = Inputs.AST.getSourceManager();
+ const SelectionTree::Node *N = Inputs.ASTSelection.commonAncestor();
+ if (!N)
+ return false;
+ Exp = N->ASTNode.get<Expr>();
+ if (!Exp)
+ return false;
+ return (Stm = getStmt(N, M));
+}
+
+Expected<tooling::Replacements>
+ExtractVariable::apply(const Selection &Inputs) {
+ auto &Ctx = Inputs.AST.getASTContext();
+ const SourceManager &SrcMgr = Inputs.AST.getSourceManager();
+ auto StmRng =
+ toHalfOpenFileRange(SrcMgr, Ctx.getLangOpts(), Stm->getSourceRange());
+ auto ExpRng =
+ toHalfOpenFileRange(SrcMgr, Ctx.getLangOpts(), Exp->getSourceRange());
+ auto ExpCode = toSourceCode(SrcMgr, *ExpRng);
+ std::string VarName = "dummy";
+ std::string ExtractedVarDecl =
+ std::string("auto ") + VarName + " = " + ExpCode.str() + "; ";
+ tooling::Replacements Result;
+ // insert new variable declaration
+ if (auto Err = Result.add(tooling::Replacement(
+ Ctx.getSourceManager(), StmRng->getBegin(), 0, ExtractedVarDecl)))
+ return std::move(Err);
+ // replace expression with variable name
+ if (auto Err = Result.add(tooling::Replacement(
+ Ctx.getSourceManager(), ExpRng->getBegin(), ExpCode.size(), "dummy")))
+ return std::move(Err);
+ return Result;
+}
+
+std::string ExtractVariable::title() const {
+ return "Extract to dummy variable";
+}
+
+} // namespace
+} // namespace clangd
+} // namespace clang
Index: clang-tools-extra/clangd/refactor/tweaks/CMakeLists.txt
===================================================================
--- clang-tools-extra/clangd/refactor/tweaks/CMakeLists.txt
+++ clang-tools-extra/clangd/refactor/tweaks/CMakeLists.txt
@@ -14,6 +14,7 @@
add_clang_library(clangDaemonTweaks OBJECT
RawStringLiteral.cpp
SwapIfBranches.cpp
+ ExtractVariable.cpp
LINK_LIBS
clangAST
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