UndefCapturedBlockVarChecker.cpp source code [clang_source_code/lib/StaticAnalyzer/Checkers/UndefCapturedBlockVarChecker.cpp]

1	// UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -- 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 checker detects blocks that capture uninitialized values.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
14	#include "clang/AST/Attr.h"
15	#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
16	#include "clang/StaticAnalyzer/Core/Checker.h"
17	#include "clang/StaticAnalyzer/Core/CheckerManager.h"
18	#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19	#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
20	#include "llvm/ADT/SmallString.h"
21	#include "llvm/Support/raw_ostream.h"
22
23	using namespace clang;
24	using namespace ento;
25
26	namespace {
27	class UndefCapturedBlockVarChecker
28	: public Checker< check::PostStmt<BlockExpr> > {
29	mutable std::unique_ptr<BugType> BT;
30
31	public:
32	void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
33	};
34	} // end anonymous namespace
35
36	static const DeclRefExpr FindBlockDeclRefExpr(const Stmt S,
37	const VarDecl *VD) {
38	if (const DeclRefExpr *BR = dyn_cast<DeclRefExpr>(S))
39	if (BR->getDecl() == VD)
40	return BR;
41
42	for (const Stmt *Child : S->children())
43	if (Child)
44	if (const DeclRefExpr *BR = FindBlockDeclRefExpr(Child, VD))
45	return BR;
46
47	return nullptr;
48	}
49
50	void
51	UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE,
52	CheckerContext &C) const {
53	if (!BE->getBlockDecl()->hasCaptures())
54	return;
55
56	ProgramStateRef state = C.getState();
57	auto *R = cast<BlockDataRegion>(C.getSVal(BE).getAsRegion());
58
59	BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
60	E = R->referenced_vars_end();
61
62	for (; I != E; ++I) {
63	// This VarRegion is the region associated with the block; we need
64	// the one associated with the encompassing context.
65	const VarRegion *VR = I.getCapturedRegion();
66	const VarDecl *VD = VR->getDecl();
67
68	if (VD->hasAttr<BlocksAttr>() \|\| !VD->hasLocalStorage())
69	continue;
70
71	// Get the VarRegion associated with VD in the local stack frame.
72	if (Optional<UndefinedVal> V =
73	state->getSVal(I.getOriginalRegion()).getAs<UndefinedVal>()) {
74	if (ExplodedNode *N = C.generateErrorNode()) {
75	if (!BT)
76	BT.reset(
77	new BuiltinBug(this, "uninitialized variable captured by block"));
78
79	// Generate a bug report.
80	SmallString<128> buf;
81	llvm::raw_svector_ostream os(buf);
82
83	os << "Variable '" << VD->getName()
84	<< "' is uninitialized when captured by block";
85
86	auto R = llvm::make_unique<BugReport>(*BT, os.str(), N);
87	if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
88	R->addRange(Ex->getSourceRange());
89	R->addVisitor(llvm::make_unique<FindLastStoreBRVisitor>(
90	V, VR, /EnableNullFPSuppression*/ false));
91	R->disablePathPruning();
92	// need location of block
93	C.emitReport(std::move(R));
94	}
95	}
96	}
97	}
98
99	void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
100	mgr.registerChecker<UndefCapturedBlockVarChecker>();
101	}
102
103	bool ento::shouldRegisterUndefCapturedBlockVarChecker(const LangOptions &LO) {
104	return true;
105	}
106

Clang Project