| //===--- SourceCodeBuilder.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 "clang/Tooling/Transformer/SourceCodeBuilders.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| #include "clang/ASTMatchers/ASTMatchers.h" |
| #include "clang/Tooling/Transformer/SourceCode.h" |
| #include "llvm/ADT/Twine.h" |
| #include <string> |
| |
| using namespace clang; |
| using namespace tooling; |
| |
| const Expr *tooling::reallyIgnoreImplicit(const Expr &E) { |
| const Expr *Expr = E.IgnoreImplicit(); |
| if (const auto *CE = dyn_cast<CXXConstructExpr>(Expr)) { |
| if (CE->getNumArgs() > 0 && |
| CE->getArg(0)->getSourceRange() == Expr->getSourceRange()) |
| return CE->getArg(0)->IgnoreImplicit(); |
| } |
| return Expr; |
| } |
| |
| bool tooling::mayEverNeedParens(const Expr &E) { |
| const Expr *Expr = reallyIgnoreImplicit(E); |
| // We always want parens around unary, binary, and ternary operators, because |
| // they are lower precedence. |
| if (isa<UnaryOperator>(Expr) || isa<BinaryOperator>(Expr) || |
| isa<AbstractConditionalOperator>(Expr)) |
| return true; |
| |
| // We need parens around calls to all overloaded operators except: function |
| // calls, subscripts, and expressions that are already part of an (implicit) |
| // call to operator->. These latter are all in the same precedence level as |
| // dot/arrow and that level is left associative, so they don't need parens |
| // when appearing on the left. |
| if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr)) |
| return Op->getOperator() != OO_Call && Op->getOperator() != OO_Subscript && |
| Op->getOperator() != OO_Arrow; |
| |
| return false; |
| } |
| |
| bool tooling::needParensAfterUnaryOperator(const Expr &E) { |
| const Expr *Expr = reallyIgnoreImplicit(E); |
| if (isa<BinaryOperator>(Expr) || isa<AbstractConditionalOperator>(Expr)) |
| return true; |
| |
| if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr)) |
| return Op->getNumArgs() == 2 && Op->getOperator() != OO_PlusPlus && |
| Op->getOperator() != OO_MinusMinus && Op->getOperator() != OO_Call && |
| Op->getOperator() != OO_Subscript; |
| |
| return false; |
| } |
| |
| bool tooling::isKnownPointerLikeType(QualType Ty, ASTContext &Context) { |
| using namespace ast_matchers; |
| const auto PointerLikeTy = type(hasUnqualifiedDesugaredType( |
| recordType(hasDeclaration(cxxRecordDecl(hasAnyName( |
| "::std::unique_ptr", "::std::shared_ptr", "::std::weak_ptr", |
| "::std::optional", "::absl::optional", "::llvm::Optional", |
| "absl::StatusOr", "::llvm::Expected")))))); |
| return match(PointerLikeTy, Ty, Context).size() > 0; |
| } |
| |
| llvm::Optional<std::string> tooling::buildParens(const Expr &E, |
| const ASTContext &Context) { |
| StringRef Text = getText(E, Context); |
| if (Text.empty()) |
| return llvm::None; |
| if (mayEverNeedParens(E)) |
| return ("(" + Text + ")").str(); |
| return Text.str(); |
| } |
| |
| llvm::Optional<std::string> |
| tooling::buildDereference(const Expr &E, const ASTContext &Context) { |
| if (const auto *Op = dyn_cast<UnaryOperator>(&E)) |
| if (Op->getOpcode() == UO_AddrOf) { |
| // Strip leading '&'. |
| StringRef Text = |
| getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context); |
| if (Text.empty()) |
| return llvm::None; |
| return Text.str(); |
| } |
| |
| StringRef Text = getText(E, Context); |
| if (Text.empty()) |
| return llvm::None; |
| // Add leading '*'. |
| if (needParensAfterUnaryOperator(E)) |
| return ("*(" + Text + ")").str(); |
| return ("*" + Text).str(); |
| } |
| |
| llvm::Optional<std::string> tooling::buildAddressOf(const Expr &E, |
| const ASTContext &Context) { |
| if (E.isImplicitCXXThis()) |
| return std::string("this"); |
| if (const auto *Op = dyn_cast<UnaryOperator>(&E)) |
| if (Op->getOpcode() == UO_Deref) { |
| // Strip leading '*'. |
| StringRef Text = |
| getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context); |
| if (Text.empty()) |
| return llvm::None; |
| return Text.str(); |
| } |
| // Add leading '&'. |
| StringRef Text = getText(E, Context); |
| if (Text.empty()) |
| return llvm::None; |
| if (needParensAfterUnaryOperator(E)) { |
| return ("&(" + Text + ")").str(); |
| } |
| return ("&" + Text).str(); |
| } |
| |
| // Append the appropriate access operation (syntactically) to `E`, assuming `E` |
| // is a non-pointer value. |
| static llvm::Optional<std::string> |
| buildAccessForValue(const Expr &E, const ASTContext &Context) { |
| if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E)) |
| if (Op->getOpcode() == UO_Deref) { |
| // Strip leading '*', add following '->'. |
| const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts(); |
| StringRef DerefText = getText(*SubExpr, Context); |
| if (DerefText.empty()) |
| return llvm::None; |
| if (needParensBeforeDotOrArrow(*SubExpr)) |
| return ("(" + DerefText + ")->").str(); |
| return (DerefText + "->").str(); |
| } |
| |
| // Add following '.'. |
| StringRef Text = getText(E, Context); |
| if (Text.empty()) |
| return llvm::None; |
| if (needParensBeforeDotOrArrow(E)) { |
| return ("(" + Text + ").").str(); |
| } |
| return (Text + ".").str(); |
| } |
| |
| // Append the appropriate access operation (syntactically) to `E`, assuming `E` |
| // is a pointer value. |
| static llvm::Optional<std::string> |
| buildAccessForPointer(const Expr &E, const ASTContext &Context) { |
| if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E)) |
| if (Op->getOpcode() == UO_AddrOf) { |
| // Strip leading '&', add following '.'. |
| const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts(); |
| StringRef DerefText = getText(*SubExpr, Context); |
| if (DerefText.empty()) |
| return llvm::None; |
| if (needParensBeforeDotOrArrow(*SubExpr)) |
| return ("(" + DerefText + ").").str(); |
| return (DerefText + ".").str(); |
| } |
| |
| // Add following '->'. |
| StringRef Text = getText(E, Context); |
| if (Text.empty()) |
| return llvm::None; |
| if (needParensBeforeDotOrArrow(E)) |
| return ("(" + Text + ")->").str(); |
| return (Text + "->").str(); |
| } |
| |
| llvm::Optional<std::string> tooling::buildDot(const Expr &E, |
| const ASTContext &Context) { |
| return buildAccessForValue(E, Context); |
| } |
| |
| llvm::Optional<std::string> tooling::buildArrow(const Expr &E, |
| const ASTContext &Context) { |
| return buildAccessForPointer(E, Context); |
| } |
| |
| // If `E` is an overloaded-operator call of kind `K` on an object `O`, returns |
| // `O`. Otherwise, returns `nullptr`. |
| static const Expr *maybeGetOperatorObjectArg(const Expr &E, |
| OverloadedOperatorKind K) { |
| if (const auto *OpCall = dyn_cast<clang::CXXOperatorCallExpr>(&E)) { |
| if (OpCall->getOperator() == K && OpCall->getNumArgs() == 1) |
| return OpCall->getArg(0); |
| } |
| return nullptr; |
| } |
| |
| static bool treatLikePointer(QualType Ty, PLTClass C, ASTContext &Context) { |
| switch (C) { |
| case PLTClass::Value: |
| return false; |
| case PLTClass::Pointer: |
| return isKnownPointerLikeType(Ty, Context); |
| } |
| llvm_unreachable("Unknown PLTClass enum"); |
| } |
| |
| // FIXME: move over the other `maybe` functionality from Stencil. Should all be |
| // in one place. |
| llvm::Optional<std::string> tooling::buildAccess(const Expr &RawExpression, |
| ASTContext &Context, |
| PLTClass Classification) { |
| if (RawExpression.isImplicitCXXThis()) |
| // Return the empty string, because `None` signifies some sort of failure. |
| return std::string(); |
| |
| const Expr *E = RawExpression.IgnoreImplicitAsWritten(); |
| |
| if (E->getType()->isAnyPointerType() || |
| treatLikePointer(E->getType(), Classification, Context)) { |
| // Strip off operator-> calls. They can only occur inside an actual arrow |
| // member access, so we treat them as equivalent to an actual object |
| // expression. |
| if (const auto *Obj = maybeGetOperatorObjectArg(*E, clang::OO_Arrow)) |
| E = Obj; |
| return buildAccessForPointer(*E, Context); |
| } |
| |
| if (const auto *Obj = maybeGetOperatorObjectArg(*E, clang::OO_Star)) { |
| if (treatLikePointer(Obj->getType(), Classification, Context)) |
| return buildAccessForPointer(*Obj, Context); |
| }; |
| |
| return buildAccessForValue(*E, Context); |
| } |