1 //=======- ASTUtis.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 #ifndef LLVM_CLANG_ANALYZER_WEBKIT_ASTUTILS_H
10 #define LLVM_CLANG_ANALYZER_WEBKIT_ASTUTILS_H
11 
12 #include "clang/AST/Decl.h"
13 #include "llvm/ADT/APInt.h"
14 #include "llvm/Support/Casting.h"
15 
16 #include <string>
17 #include <utility>
18 
19 namespace clang {
20 class CXXRecordDecl;
21 class CXXBaseSpecifier;
22 class FunctionDecl;
23 class CXXMethodDecl;
24 class Expr;
25 
26 /// If passed expression is of type uncounted pointer/reference we try to find
27 /// the origin of this pointer. Example: Origin can be a local variable, nullptr
28 /// constant or this-pointer.
29 ///
30 /// Certain subexpression nodes represent transformations that don't affect
31 /// where the memory address originates from. We try to traverse such
32 /// subexpressions to get to the relevant child nodes. Whenever we encounter a
33 /// subexpression that either can't be ignored, we don't model its semantics or
34 /// that has multiple children we stop.
35 ///
36 /// \p E is an expression of uncounted pointer/reference type.
37 /// If \p StopAtFirstRefCountedObj is true and we encounter a subexpression that
38 /// represents ref-counted object during the traversal we return relevant
39 /// sub-expression and true.
40 ///
41 /// \returns subexpression that we traversed to and if \p
42 /// StopAtFirstRefCountedObj is true we also return whether we stopped early.
43 std::pair<const clang::Expr *, bool>
44 tryToFindPtrOrigin(const clang::Expr *E, bool StopAtFirstRefCountedObj);
45 
46 /// For \p E referring to a ref-countable/-counted pointer/reference we return
47 /// whether it's a safe call argument. Examples: function parameter or
48 /// this-pointer. The logic relies on the set of recursive rules we enforce for
49 /// WebKit codebase.
50 ///
51 /// \returns Whether \p E is a safe call arugment.
52 bool isASafeCallArg(const clang::Expr *E);
53 
54 /// \returns name of AST node or empty string.
55 template <typename T> std::string safeGetName(const T *ASTNode) {
56   const auto *const ND = llvm::dyn_cast_or_null<clang::NamedDecl>(ASTNode);
57   if (!ND)
58     return "";
59 
60   // In case F is for example "operator|" the getName() method below would
61   // assert.
62   if (!ND->getDeclName().isIdentifier())
63     return "";
64 
65   return ND->getName().str();
66 }
67 
68 } // namespace clang
69 
70 #endif
71