1 /* This Source Code Form is subject to the terms of the Mozilla Public
2  * License, v. 2.0. If a copy of the MPL was not distributed with this
3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
4 
5 #ifndef VariableUsageHelpers_h__
6 #define VariableUsageHelpers_h__
7 
8 #include "plugin.h"
9 
10 /// Returns a list of the statements where the given declaration is used as an
11 /// rvalue (within the provided function).
12 ///
13 /// WARNING: incomplete behaviour/implementation for general-purpose use outside
14 /// of escapesFunction(). This only detects very basic usages (see
15 /// implementation for more details).
16 std::vector<const Stmt *> getUsageAsRvalue(const ValueDecl *ValueDeclaration,
17                                            const FunctionDecl *FuncDecl);
18 
19 /// This is the error enumeration for escapesFunction(), describing all the
20 /// possible error cases.
21 enum class EscapesFunctionError {
22   ConstructorDeclNotFound = 1,
23   FunctionDeclNotFound,
24   FunctionIsBuiltin,
25   FunctionIsVariadic,
26   ExprNotInCall,
27   NoParamForArg,
28   ArgAndParamNotPointers
29 };
30 
31 /// Required by the std::error_code system to convert our enum into a general
32 /// error code.
33 std::error_code make_error_code(EscapesFunctionError);
34 
35 /// Returns a (statement, decl) tuple if an argument from an argument list
36 /// escapes the function scope through globals/statics/other things. The
37 /// statement is where the value escapes the function, while the declaration
38 /// points to what it escapes through. If the argument doesn't escape the
39 /// function, the tuple will only contain nullptrs.
40 /// If the analysis runs into an unexpected error or into an unimplemented
41 /// configuration, it will return an error_code of type EscapesFunctionError
42 /// representing the precise issue.
43 ///
44 /// WARNING: incomplete behaviour/implementation for general-purpose use outside
45 /// of DanglingOnTemporaryChecker. This only covers a limited set of cases,
46 /// mainly in terms of arguments and parameter types.
47 ErrorOr<std::tuple<const Stmt *, const Decl *>>
48 escapesFunction(const Expr *Arg, const FunctionDecl *FuncDecl,
49                 const Expr *const *Arguments, unsigned NumArgs);
50 
51 /// Helper function taking a call expression.
52 ErrorOr<std::tuple<const Stmt *, const Decl *>>
53 escapesFunction(const Expr *Arg, const CallExpr *Call);
54 
55 /// Helper function taking a construct expression.
56 ErrorOr<std::tuple<const Stmt *, const Decl *>>
57 escapesFunction(const Expr *Arg, const CXXConstructExpr *Construct);
58 
59 /// Helper function taking an operator call expression.
60 ErrorOr<std::tuple<const Stmt *, const Decl *>>
61 escapesFunction(const Expr *Arg, const CXXOperatorCallExpr *OpCall);
62 
63 #endif
64