clang 10.0.0git

LexicallyOrderedRecursiveASTVisitor.h
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1 //===--- LexicallyOrderedRecursiveASTVisitor.h - ----------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the LexicallyOrderedRecursiveASTVisitor interface, which
10 // recursively traverses the entire AST in a lexical order.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #ifndef LLVM_CLANG_AST_LEXICALLY_ORDERED_RECURSIVEASTVISITOR_H
15 #define LLVM_CLANG_AST_LEXICALLY_ORDERED_RECURSIVEASTVISITOR_H
16
17 #include "clang/AST/RecursiveASTVisitor.h"
18 #include "clang/Basic/LLVM.h"
19 #include "clang/Basic/SourceManager.h"
20 #include "llvm/Support/SaveAndRestore.h"
21
22 namespace clang {
23
24 /// A RecursiveASTVisitor subclass that guarantees that AST traversal is
25 /// performed in a lexical order (i.e. the order in which declarations are
26 /// written in the source).
27 ///
28 /// RecursiveASTVisitor doesn't guarantee lexical ordering because there are
29 /// some declarations, like Objective-C @implementation declarations
30 /// that might be represented in the AST differently to how they were written
31 /// in the source.
32 /// In particular, Objective-C @implementation declarations may contain
33 /// non-Objective-C declarations, like functions:
34 ///
35 /// @implementation MyClass
36 ///
37 /// - (void) method { }
38 /// void normalFunction() { }
39 ///
40 /// @end
41 ///
42 /// Clang's AST stores these declarations outside of the @implementation
43 /// declaration, so the example above would be represented using the following
44 /// AST:
45 /// |-ObjCImplementationDecl ... MyClass
46 /// | `-ObjCMethodDecl ... method
47 /// | ...
48 /// `-FunctionDecl ... normalFunction
49 /// ...
50 ///
51 /// This class ensures that these declarations are traversed before the
52 /// corresponding TraverseDecl for the @implementation returns. This ensures
53 /// that the lexical parent relationship between these declarations and the
54 /// @implementation is preserved while traversing the AST. Note that the
55 /// current implementation doesn't mix these declarations with the declarations
56 /// contained in the @implementation, so the traversal of all of the
57 /// declarations in the @implementation still doesn't follow the lexical order.
58 template <typename Derived>
59 class LexicallyOrderedRecursiveASTVisitor
60 : public RecursiveASTVisitor<Derived> {
61 using BaseType = RecursiveASTVisitor<Derived>;
62
63 public:
64 LexicallyOrderedRecursiveASTVisitor(const SourceManager &SM) : SM(SM) {}
65
66 bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D) {
67 // Objective-C @implementation declarations should not trigger early exit
68 // until the additional decls are traversed as their children are not
69 // lexically ordered.
70 bool Result = BaseType::TraverseObjCImplementationDecl(D);
71 return TraverseAdditionalLexicallyNestedDeclarations() ? Result : false;
72 }
73
74 bool TraverseObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
75 bool Result = BaseType::TraverseObjCCategoryImplDecl(D);
76 return TraverseAdditionalLexicallyNestedDeclarations() ? Result : false;
77 }
78
79 bool TraverseDeclContextHelper(DeclContext *DC) {
80 if (!DC)
81 return true;
82
83 for (auto I = DC->decls_begin(), E = DC->decls_end(); I != E;) {
84 Decl *Child = *I;
85 if (BaseType::canIgnoreChildDeclWhileTraversingDeclContext(Child)) {
86 ++I;
87 continue;
88 }
89 if (!isa<ObjCImplementationDecl>(Child) &&
90 !isa<ObjCCategoryImplDecl>(Child)) {
91 if (!BaseType::getDerived().TraverseDecl(Child))
92 return false;
93 ++I;
94 continue;
95 }
96 // Gather declarations that follow the Objective-C implementation
97 // declarations but are lexically contained in the implementation.
98 LexicallyNestedDeclarations.clear();
99 for (++I; I != E; ++I) {
100 Decl *Sibling = *I;
101 if (!SM.isBeforeInTranslationUnit(Sibling->getBeginLoc(),
102 Child->getEndLoc()))
103 break;
104 if (!BaseType::canIgnoreChildDeclWhileTraversingDeclContext(Sibling))
105 LexicallyNestedDeclarations.push_back(Sibling);
106 }
107 if (!BaseType::getDerived().TraverseDecl(Child))
108 return false;
109 }
110 return true;
111 }
112
113 Stmt::child_range getStmtChildren(Stmt *S) { return S->children(); }
114
115 SmallVector<Stmt *, 8> getStmtChildren(CXXOperatorCallExpr *CE) {
116 SmallVector<Stmt *, 8> Children(CE->children());
117 bool Swap;
118 // Switch the operator and the first operand for all infix and postfix
119 // operations.
120 switch (CE->getOperator()) {
121 case OO_Arrow:
122 case OO_Call:
123 case OO_Subscript:
124 Swap = true;
125 break;
126 case OO_PlusPlus:
127 case OO_MinusMinus:
128 // These are postfix unless there is exactly one argument.
129 Swap = Children.size() != 2;
130 break;
131 default:
132 Swap = CE->isInfixBinaryOp();
133 break;
134 }
135 if (Swap && Children.size() > 1)
136 std::swap(Children[0], Children[1]);
137 return Children;
138 }
139
140 private:
141 bool TraverseAdditionalLexicallyNestedDeclarations() {
142 // FIXME: Ideally the gathered declarations and the declarations in the
143 // @implementation should be mixed and sorted to get a true lexical order,
144 // but right now we only care about getting the correct lexical parent, so
145 // we can traverse the gathered nested declarations after the declarations
146 // in the decl context.
147 assert(!BaseType::getDerived().shouldTraversePostOrder() &&
148 "post-order traversal is not supported for lexically ordered "
149 "recursive ast visitor");
150 for (Decl *D : LexicallyNestedDeclarations) {
151 if (!BaseType::getDerived().TraverseDecl(D))
152 return false;
153 }
154 return true;
155 }
156
157 const SourceManager &SM;
158 llvm::SmallVector<Decl *, 8> LexicallyNestedDeclarations;
159 };
160
161 } // end namespace clang
162
163 #endif // LLVM_CLANG_AST_LEXICALLY_ORDERED_RECURSIVEASTVISITOR_H
clang::CXXOperatorCallExpr
A call to an overloaded operator written using operator syntax.
Definition: ExprCXX.h:78
clang::Stmt
Stmt - This represents one statement.
Definition: Stmt.h:66
clang::LexicallyOrderedRecursiveASTVisitor::LexicallyOrderedRecursiveASTVisitor
LexicallyOrderedRecursiveASTVisitor(const SourceManager &SM)
Definition: LexicallyOrderedRecursiveASTVisitor.h:64
SourceManager.h
Defines the SourceManager interface.
clang::Decl
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
clang::RecursiveASTVisitor::shouldTraversePostOrder
bool shouldTraversePostOrder() const
Return whether this visitor should traverse post-order.
Definition: RecursiveASTVisitor.h:177
clang::Decl::getBeginLoc
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: DeclBase.h:421
clang::SourceManager::isBeforeInTranslationUnit
bool isBeforeInTranslationUnit(SourceLocation LHS, SourceLocation RHS) const
Determines the order of 2 source locations in the translation unit.
Definition: SourceManager.cpp:1936
clang::Stmt::child_range
llvm::iterator_range< child_iterator > child_range
Definition: Stmt.h:1180
clang::Decl::getEndLoc
SourceLocation getEndLoc() const LLVM_READONLY
Definition: DeclBase.h:425
clang::LexicallyOrderedRecursiveASTVisitor::TraverseObjCCategoryImplDecl
bool TraverseObjCCategoryImplDecl(ObjCCategoryImplDecl *D)
Definition: LexicallyOrderedRecursiveASTVisitor.h:74
clang::RecursiveASTVisitor::getDerived
Derived & getDerived()
Return a reference to the derived class.
Definition: RecursiveASTVisitor.h:162
clang::LexicallyOrderedRecursiveASTVisitor::TraverseDeclContextHelper
bool TraverseDeclContextHelper(DeclContext *DC)
Definition: LexicallyOrderedRecursiveASTVisitor.h:79
clang::LexicallyOrderedRecursiveASTVisitor::getStmtChildren
SmallVector< Stmt *, 8 > getStmtChildren(CXXOperatorCallExpr *CE)
Definition: LexicallyOrderedRecursiveASTVisitor.h:115
clang::RecursiveASTVisitor::TraverseDecl
bool TraverseDecl(Decl *D)
Recursively visit a declaration, by dispatching to Traverse*Decl() based on the argument&#39;s dynamic ty...
Definition: RecursiveASTVisitor.h:713
LLVM.h
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
clang::CallExpr::children
child_range children()
Definition: Expr.h:2811
clang::Stmt::children
child_range children()
Definition: Stmt.cpp:224
clang::RecursiveASTVisitor
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
Definition: RecursiveASTVisitor.h:151
clang::RecursiveASTVisitor::canIgnoreChildDeclWhileTraversingDeclContext
bool canIgnoreChildDeclWhileTraversingDeclContext(const Decl *Child)
RecursiveASTVisitor.h
clang::ObjCSubstitutionContext::Result
The result type of a method or function.
clang::LexicallyOrderedRecursiveASTVisitor::getStmtChildren
Stmt::child_range getStmtChildren(Stmt *S)
Definition: LexicallyOrderedRecursiveASTVisitor.h:113
clang::DeclContext::decls_begin
decl_iterator decls_begin() const
Definition: DeclBase.cpp:1388
llvm::SmallVector
Definition: LLVM.h:35
clang::CXXOperatorCallExpr::isInfixBinaryOp
bool isInfixBinaryOp() const
Is this written as an infix binary operator?
Definition: ExprCXX.cpp:46
clang::LexicallyOrderedRecursiveASTVisitor
A RecursiveASTVisitor subclass that guarantees that AST traversal is performed in a lexical order (i...
Definition: LexicallyOrderedRecursiveASTVisitor.h:59
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:21
clang::DeclContext
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1271
clang::CXXOperatorCallExpr::getOperator
OverloadedOperatorKind getOperator() const
Returns the kind of overloaded operator that this expression refers to.
Definition: ExprCXX.h:107
clang::ObjCImplementationDecl
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2566
clang::LexicallyOrderedRecursiveASTVisitor::TraverseObjCImplementationDecl
bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D)
Definition: LexicallyOrderedRecursiveASTVisitor.h:66
clang::ObjCCategoryImplDecl
ObjCCategoryImplDecl - An object of this class encapsulates a category @implementation declaration...
Definition: DeclObjC.h:2513
clang::SourceManager
This class handles loading and caching of source files into memory.
Definition: SourceManager.h:596
clang::DeclContext::decls_end
decl_iterator decls_end() const
Definition: DeclBase.h:2035