SureYeaah created this revision. SureYeaah added reviewers: sammccall, kadircet. Herald added subscribers: cfe-commits, arphaman, jkorous, MaskRay, ilya-biryukov. Herald added a project: clang.
- Added a SelectionTreeVisitor to check for broken control flow - Added unittests Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D66732 Files: clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.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 @@ -625,14 +625,22 @@ // FIXME: ExtractFunction should be unavailable inside loop construct // initalizer/condition. EXPECT_THAT(apply(" for([[int i = 0;]];);"), HasSubstr("extracted")); + // We should be able to extract break/continue with a parent loop/switch. + EXPECT_THAT(apply(" [[for(;;) if(1) break;]] "), HasSubstr("extracted")); + EXPECT_THAT(apply(" for(;;) [[while(1) break;]] "), HasSubstr("extracted")); + EXPECT_THAT(apply(" [[switch(1) { break; }]]"), HasSubstr("extracted")); + EXPECT_THAT(apply(" [[while(1) switch(1) { continue; }]]"), + HasSubstr("extracted")); // Don't extract because needs hoisting. EXPECT_THAT(apply(" [[int a = 5;]] a++; "), StartsWith("fail")); // Don't extract return EXPECT_THAT(apply(" if(true) [[return;]] "), StartsWith("fail")); - // Don't extract break and continue. - // FIXME: We should be able to extract this since it's non broken. - EXPECT_THAT(apply(" [[for(;;) break;]] "), StartsWith("fail")); - EXPECT_THAT(apply(" for(;;) [[continue;]] "), StartsWith("fail")); + // Don't extract break and continue without a loop/switch parent. + EXPECT_THAT(apply(" for(;;) [[if(1) continue;]] "), StartsWith("fail")); + EXPECT_THAT(apply(" while(1) [[if(1) break;]] "), StartsWith("fail")); + EXPECT_THAT(apply(" switch(1) { [[break;]] }"), StartsWith("fail")); + EXPECT_THAT(apply(" for(;;) { [[while(1) break; break;]] }"), + StartsWith("fail")); } TEST_F(ExtractFunctionTest, FileTest) { Index: clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.cpp =================================================================== --- clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.cpp +++ clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.cpp @@ -28,7 +28,6 @@ // - Always passed by l-value reference // - No return // - Cannot move declarations before extracting -// - Doesn't check for broken control flow // // 1. ExtractFunction is the tweak subclass // - Prepare does basic analysis of the selection and is therefore fast. @@ -39,8 +38,9 @@ // enclosing function. // 3. NewFunction stores properties of the extracted function and provides // methods for rendering it. -// 4. CapturedZoneInfo uses a RAV to capture information about the extraction -// like declarations, existing return statements, broken control flow, etc. +// 4. CapturedZoneInfo uses a RAV and SelectionTreeVisitor to capture +// information about the extraction like declarations, existing return +// statements, broken control flow, etc. // 5. getExtractedFunction is responsible for analyzing the CapturedZoneInfo and // creating a NewFunction. // Design Doc at <TODO: Share design doc> @@ -55,6 +55,7 @@ #include "clang/AST/DeclTemplate.h" #include "clang/AST/RecursiveASTVisitor.h" #include "clang/AST/Stmt.h" +#include "clang/AST/StmtCXX.h" #include "clang/Basic/LangOptions.h" #include "clang/Basic/SourceLocation.h" #include "clang/Basic/SourceManager.h" @@ -360,8 +361,8 @@ llvm::DenseMap<const Decl *, DeclInformation> DeclInfoMap; // True if there is a return statement in zone. bool HasReturnStmt = false; - // For now we just care whether there exists a break/continue in zone. - bool HasBreakOrContinue = false; + // True if extracting break or continue without corresponding loop/switch. + bool BrokenControlFlow = false; // FIXME: capture TypeAliasDecl and UsingDirectiveDecl // FIXME: Capture type information as well. // Return reference for a Decl, adding it if not already present. @@ -403,7 +404,8 @@ class ExtractionZoneVisitor : public clang::RecursiveASTVisitor<ExtractionZoneVisitor> { public: - ExtractionZoneVisitor(const ExtractionZone &ExtZone) : ExtZone(ExtZone) { + ExtractionZoneVisitor(CapturedZoneInfo &Info, const ExtractionZone &ExtZone) + : Info(Info), ExtZone(ExtZone) { TraverseDecl(const_cast<FunctionDecl *>( ExtZone.EnclosingFunction->ASTNode.get<FunctionDecl>())); } @@ -424,12 +426,61 @@ Info.HasReturnStmt = true; return true; } - - CapturedZoneInfo Info; + CapturedZoneInfo &Info; const ExtractionZone &ExtZone; }; - ExtractionZoneVisitor Visitor(ExtZone); - return std::move(Visitor.Info); + + class SelectionTreeVisitor { + // Returns tuple denoting whether we can Break/Continue out of a node. + std::tuple<bool, bool> canHaveBreakContinueAsChild(const Node *N) { + const Stmt *S = N->ASTNode.get<Stmt>(); + bool Break = false; + bool Continue = false; + // We can break/continue out of a loop + if (dyn_cast_or_null<WhileStmt>(S) || dyn_cast_or_null<ForStmt>(S) || + dyn_cast_or_null<CXXForRangeStmt>(S) || dyn_cast_or_null<DoStmt>(S)) + Break = Continue = true; + // We can only break out of a switch + else if (dyn_cast_or_null<SwitchStmt>(S)) + Break = true; + return {Break, Continue}; + } + // Perform a depth first traversal of selection tree to look for broken + // break/continue in Extraction zone. + void traverse(const Node *CurNode) { + bool CanHaveBreak, CanHaveContinue; + std::tie(CanHaveBreak, CanHaveContinue) = + canHaveBreakContinueAsChild(CurNode); + BreakParents += CanHaveBreak; + ContinueParents += CanHaveContinue; + // If we find a break or continue without a corresponding parent that can + // have a break/continue inside it, we have broken control flow. + if ((CurNode->ASTNode.get<BreakStmt>() && !BreakParents) || + (CurNode->ASTNode.get<ContinueStmt>() && !ContinueParents)) + Info.BrokenControlFlow = true; + for (const Node *ChildNode : CurNode->Children) { + traverse(ChildNode); + } + BreakParents -= CanHaveBreak; + ContinueParents -= CanHaveContinue; + } + // Current number of nodes that can we can break/continue out of. + unsigned BreakParents = 0; + unsigned ContinueParents = 0; + CapturedZoneInfo &Info; + + public: + SelectionTreeVisitor(CapturedZoneInfo &Info, const Node *ZoneParent) + : Info(Info) { + for (const Node *RootStmt : ZoneParent->Children) { + traverse(RootStmt); + } + } + }; + CapturedZoneInfo Info; + ExtractionZoneVisitor Visitor(Info, ExtZone); + SelectionTreeVisitor SelectionVisitor(Info, ExtZone.Parent); + return Info; } // Adds parameters to ExtractedFunc. @@ -509,9 +560,8 @@ const SourceManager &SM, const LangOptions &LangOpts) { CapturedZoneInfo CapturedInfo = captureZoneInfo(ExtZone); - // Bail out if any break of continue exists - // FIXME: check for broken control flow only - if (CapturedInfo.HasBreakOrContinue) + // Bail out if trying to extract broken control flow + if (CapturedInfo.BrokenControlFlow) return llvm::None; auto SemicolonPolicy = getSemicolonPolicy(ExtZone, SM, LangOpts); NewFunction ExtractedFunc(ExtZone.ZoneRange, ExtZone.getInsertionPoint(),
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