clang  15.0.0git
ASTUtils.h
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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 Expr;
21 
22 /// This function de-facto defines a set of transformations that we consider
23 /// safe (in heuristical sense). These transformation if passed a safe value as
24 /// an input should provide a safe value (or an object that provides safe
25 /// values).
26 ///
27 /// For more context see Static Analyzer checkers documentation - specifically
28 /// webkit.UncountedCallArgsChecker checker. Allowed list of transformations:
29 /// - constructors of ref-counted types (including factory methods)
30 /// - getters of ref-counted types
31 /// - member overloaded operators
32 /// - casts
33 /// - unary operators like ``&`` or ``*``
34 ///
35 /// If passed expression is of type uncounted pointer/reference we try to find
36 /// the "origin" of the pointer value.
37 /// Origin can be for example a local variable, nullptr, constant or
38 /// this-pointer.
39 ///
40 /// Certain subexpression nodes represent transformations that don't affect
41 /// where the memory address originates from. We try to traverse such
42 /// subexpressions to get to the relevant child nodes. Whenever we encounter a
43 /// subexpression that either can't be ignored, we don't model its semantics or
44 /// that has multiple children we stop.
45 ///
46 /// \p E is an expression of uncounted pointer/reference type.
47 /// If \p StopAtFirstRefCountedObj is true and we encounter a subexpression that
48 /// represents ref-counted object during the traversal we return relevant
49 /// sub-expression and true.
50 ///
51 /// \returns subexpression that we traversed to and if \p
52 /// StopAtFirstRefCountedObj is true we also return whether we stopped early.
53 std::pair<const clang::Expr *, bool>
54 tryToFindPtrOrigin(const clang::Expr *E, bool StopAtFirstRefCountedObj);
55 
56 /// For \p E referring to a ref-countable/-counted pointer/reference we return
57 /// whether it's a safe call argument. Examples: function parameter or
58 /// this-pointer. The logic relies on the set of recursive rules we enforce for
59 /// WebKit codebase.
60 ///
61 /// \returns Whether \p E is a safe call arugment.
62 bool isASafeCallArg(const clang::Expr *E);
63 
64 /// \returns name of AST node or empty string.
65 template <typename T> std::string safeGetName(const T *ASTNode) {
66  const auto *const ND = llvm::dyn_cast_or_null<clang::NamedDecl>(ASTNode);
67  if (!ND)
68  return "";
69 
70  // In case F is for example "operator|" the getName() method below would
71  // assert.
72  if (!ND->getDeclName().isIdentifier())
73  return "";
74 
75  return ND->getName().str();
76 }
77 
78 } // namespace clang
79 
80 #endif
string
string(SUBSTRING ${CMAKE_CURRENT_BINARY_DIR} 0 ${PATH_LIB_START} PATH_HEAD) string(SUBSTRING $
Definition: CMakeLists.txt:22
clang::tryToFindPtrOrigin
std::pair< const Expr *, bool > tryToFindPtrOrigin(const Expr *E, bool StopAtFirstRefCountedObj)
This function de-facto defines a set of transformations that we consider safe (in heuristical sense).
Definition: ASTUtils.cpp:20
clang::isASafeCallArg
bool isASafeCallArg(const Expr *E)
For E referring to a ref-countable/-counted pointer/reference we return whether it's a safe call argu...
Definition: ASTUtils.cpp:82
Decl.h
clang::safeGetName
std::string safeGetName(const T *ASTNode)
Definition: ASTUtils.h:65
clang
Definition: CalledOnceCheck.h:17
clang::Expr
This represents one expression.
Definition: Expr.h:109