UninitializedValues.h source code [clang_source_code/include/clang/Analysis/Analyses/UninitializedValues.h]

1	//=- UninitializedValues.h - Finding uses of uninitialized values -- 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 APIs for invoking and reported uninitialized values
10	// warnings.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_UNINITIALIZEDVALUES_H
15	#define LLVM_CLANG_ANALYSIS_ANALYSES_UNINITIALIZEDVALUES_H
16
17	#include "clang/Basic/LLVM.h"
18	#include "llvm/ADT/SmallVector.h"
19
20	namespace clang {
21
22	class AnalysisDeclContext;
23	class CFG;
24	class DeclContext;
25	class Expr;
26	class Stmt;
27	class VarDecl;
28
29	/// A use of a variable, which might be uninitialized.
30	class UninitUse {
31	public:
32	struct Branch {
33	const Stmt *Terminator;
34	unsigned Output;
35	};
36
37	private:
38	/// The expression which uses this variable.
39	const Expr *User;
40
41	/// Is this use uninitialized whenever the function is called?
42	bool UninitAfterCall = false;
43
44	/// Is this use uninitialized whenever the variable declaration is reached?
45	bool UninitAfterDecl = false;
46
47	/// Does this use always see an uninitialized value?
48	bool AlwaysUninit;
49
50	/// This use is always uninitialized if it occurs after any of these branches
51	/// is taken.
52	SmallVector<Branch, 2> UninitBranches;
53
54	public:
55	UninitUse(const Expr *User, bool AlwaysUninit)
56	: User(User), AlwaysUninit(AlwaysUninit) {}
57
58	void addUninitBranch(Branch B) {
59	UninitBranches.push_back(B);
60	}
61
62	void setUninitAfterCall() { UninitAfterCall = true; }
63	void setUninitAfterDecl() { UninitAfterDecl = true; }
64
65	/// Get the expression containing the uninitialized use.
66	const Expr *getUser() const { return User; }
67
68	/// The kind of uninitialized use.
69	enum Kind {
70	/// The use might be uninitialized.
71	Maybe,
72
73	/// The use is uninitialized whenever a certain branch is taken.
74	Sometimes,
75
76	/// The use is uninitialized the first time it is reached after we reach
77	/// the variable's declaration.
78	AfterDecl,
79
80	/// The use is uninitialized the first time it is reached after the function
81	/// is called.
82	AfterCall,
83
84	/// The use is always uninitialized.
85	Always
86	};
87
88	/// Get the kind of uninitialized use.
89	Kind getKind() const {
90	return AlwaysUninit ? Always :
91	UninitAfterCall ? AfterCall :
92	UninitAfterDecl ? AfterDecl :
93	!branch_empty() ? Sometimes : Maybe;
94	}
95
96	using branch_iterator = SmallVectorImpl<Branch>::const_iterator;
97
98	/// Branches which inevitably result in the variable being used uninitialized.
99	branch_iterator branch_begin() const { return UninitBranches.begin(); }
100	branch_iterator branch_end() const { return UninitBranches.end(); }
101	bool branch_empty() const { return UninitBranches.empty(); }
102	};
103
104	class UninitVariablesHandler {
105	public:
106	UninitVariablesHandler() = default;
107	virtual ~UninitVariablesHandler();
108
109	/// Called when the uninitialized variable is used at the given expression.
110	virtual void handleUseOfUninitVariable(const VarDecl *vd,
111	const UninitUse &use) {}
112
113	/// Called when the uninitialized variable analysis detects the
114	/// idiom 'int x = x'. All other uses of 'x' within the initializer
115	/// are handled by handleUseOfUninitVariable.
116	virtual void handleSelfInit(const VarDecl *vd) {}
117	};
118
119	struct UninitVariablesAnalysisStats {
120	unsigned NumVariablesAnalyzed;
121	unsigned NumBlockVisits;
122	};
123
124	void runUninitializedVariablesAnalysis(const DeclContext &dc, const CFG &cfg,
125	AnalysisDeclContext &ac,
126	UninitVariablesHandler &handler,
127	UninitVariablesAnalysisStats &stats);
128
129	} // namespace clang
130
131	#endif // LLVM_CLANG_ANALYSIS_ANALYSES_UNINITIALIZEDVALUES_H
132

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