1//=======- ASTUtils.cpp ------------------------------------------*- 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#include "ASTUtils.h"
10#include "PtrTypesSemantics.h"
11#include "clang/AST/CXXInheritance.h"
12#include "clang/AST/Decl.h"
13#include "clang/AST/DeclCXX.h"
14#include "clang/AST/ExprCXX.h"
15
16using llvm::Optional;
17namespace clang {
18
19std::pair<const Expr *, bool>
20tryToFindPtrOrigin(const Expr *E, bool StopAtFirstRefCountedObj) {
21  while (E) {
22    if (auto *cast = dyn_cast<CastExpr>(E)) {
23      if (StopAtFirstRefCountedObj) {
24        if (auto *ConversionFunc =
25                dyn_cast_or_null<FunctionDecl>(cast->getConversionFunction())) {
26          if (isCtorOfRefCounted(ConversionFunc))
27            return {E, true};
28        }
29      }
30      // FIXME: This can give false "origin" that would lead to false negatives
31      // in checkers. See https://reviews.llvm.org/D37023 for reference.
32      E = cast->getSubExpr();
33      continue;
34    }
35    if (auto *call = dyn_cast<CallExpr>(E)) {
36      if (auto *memberCall = dyn_cast<CXXMemberCallExpr>(call)) {
37        if (isGetterOfRefCounted(memberCall->getMethodDecl())) {
38          E = memberCall->getImplicitObjectArgument();
39          if (StopAtFirstRefCountedObj) {
40            return {E, true};
41          }
42          continue;
43        }
44      }
45
46      if (auto *operatorCall = dyn_cast<CXXOperatorCallExpr>(E)) {
47        if (operatorCall->getNumArgs() == 1) {
48          E = operatorCall->getArg(0);
49          continue;
50        }
51      }
52
53      if (auto *callee = call->getDirectCallee()) {
54        if (isCtorOfRefCounted(callee)) {
55          if (StopAtFirstRefCountedObj)
56            return {E, true};
57
58          E = call->getArg(0);
59          continue;
60        }
61
62        if (isPtrConversion(callee)) {
63          E = call->getArg(0);
64          continue;
65        }
66      }
67    }
68    if (auto *unaryOp = dyn_cast<UnaryOperator>(E)) {
69      // FIXME: Currently accepts ANY unary operator. Is it OK?
70      E = unaryOp->getSubExpr();
71      continue;
72    }
73
74    break;
75  }
76  // Some other expression.
77  return {E, false};
78}
79
80bool isASafeCallArg(const Expr *E) {
81  assert(E);
82  if (auto *Ref = dyn_cast<DeclRefExpr>(E)) {
83    if (auto *D = dyn_cast_or_null<VarDecl>(Ref->getFoundDecl())) {
84      if (isa<ParmVarDecl>(D) || D->isLocalVarDecl())
85        return true;
86    }
87  }
88
89  // TODO: checker for method calls on non-refcounted objects
90  return isa<CXXThisExpr>(E);
91}
92
93} // namespace clang
94