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//===--- ExtractionUtils.cpp - Extraction helper functions ----------------===//
//
// 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 "ExtractionUtils.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace clang;
std::optional<StringRef>
tooling::extract::nameForExtractedVariable(const Expr *E) {
if (const auto *Call = dyn_cast<CallExpr>(E)) {
if (const auto *Fn = Call->getDirectCallee())
return Fn->getName();
} else if (const auto *Msg = dyn_cast<ObjCMessageExpr>(E)) {
if (const auto *M = Msg->getMethodDecl()) {
if (M->getSelector().isUnarySelector())
return M->getSelector().getNameForSlot(0);
}
} else if (const auto *PRE = dyn_cast<ObjCPropertyRefExpr>(E)) {
if (PRE->isImplicitProperty()) {
if (const auto *M = PRE->getImplicitPropertyGetter())
return M->getSelector().getNameForSlot(0);
} else if (const auto *Prop = PRE->getExplicitProperty())
return Prop->getName();
}
return std::nullopt;
}
namespace {
/// Checks if a set of expressions is directly contained in some AST region.
class StmtReachabilityChecker
: public RecursiveASTVisitor<StmtReachabilityChecker> {
const llvm::SmallPtrSetImpl<const Stmt *> &Expressions;
unsigned Count = 0;
StmtReachabilityChecker(
const llvm::SmallPtrSetImpl<const Stmt *> &Expressions)
: Expressions(Expressions) {}
bool areAllExpressionsReached() const { return Count == Expressions.size(); }
public:
bool VisitStmt(const Stmt *S) {
if (Expressions.count(S)) {
++Count;
if (areAllExpressionsReached())
return false;
}
return true;
}
static bool areAllExpressionsReachableFrom(
CompoundStmt *S, const llvm::SmallPtrSetImpl<const Stmt *> &Expressions) {
StmtReachabilityChecker Checker(Expressions);
Checker.TraverseStmt(S);
return Checker.areAllExpressionsReached();
}
};
/// Figures out where the extracted variable should go.
class ExtractedVariableInsertionLocFinder
: public RecursiveASTVisitor<ExtractedVariableInsertionLocFinder> {
llvm::SmallPtrSet<const Stmt *, 4> Expressions;
llvm::SmallVector<std::pair<CompoundStmt *, const Stmt *>, 4>
InsertionCandidateStack;
bool IsPrevCompoundStmt = false;
public:
SourceLocation Loc;
/// Initializes the insertion location finder using the set of duplicate
/// \p Expressions from one function.
ExtractedVariableInsertionLocFinder(ArrayRef<const Expr *> Expressions) {
for (const Expr *E : Expressions)
this->Expressions.insert(E);
}
bool TraverseStmt(Stmt *S) {
if (!S)
return RecursiveASTVisitor::TraverseStmt(S);
if (IsPrevCompoundStmt && !InsertionCandidateStack.empty())
InsertionCandidateStack.back().second = S;
llvm::SaveAndRestore<bool> IsPrevCompoundStmtTracker(IsPrevCompoundStmt,
false);
if (auto *CS = dyn_cast<CompoundStmt>(S)) {
IsPrevCompoundStmt = true;
InsertionCandidateStack.emplace_back(CS, nullptr);
RecursiveASTVisitor::TraverseStmt(S);
InsertionCandidateStack.pop_back();
return true;
}
return RecursiveASTVisitor::TraverseStmt(S);
}
bool VisitStmt(const Stmt *S) {
if (Expressions.count(S)) {
// The insertion location should be in the first compound statement that
// includes all of the expressions as descendants as we want the new
// variable to be visible to all uses.
for (auto I = InsertionCandidateStack.rbegin(),
E = InsertionCandidateStack.rend();
I != E; ++I) {
if (StmtReachabilityChecker::areAllExpressionsReachableFrom(
I->first, Expressions) &&
I->second) {
Loc = I->second->getBeginLoc();
break;
}
}
return false;
}
return true;
}
};
} // end anonymous namespace
SourceLocation tooling::extract::locationForExtractedVariableDeclaration(
ArrayRef<const Expr *> Expressions, const Decl *ParentDecl,
const SourceManager &SM) {
ExtractedVariableInsertionLocFinder LocFinder(Expressions);
LocFinder.TraverseDecl(const_cast<Decl *>(ParentDecl));
SourceLocation Result = LocFinder.Loc;
if (Result.isValid() && Result.isMacroID())
return SM.getExpansionLoc(Result);
return Result;
}
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