clang 8.0.0

UndefCapturedBlockVarChecker.cpp
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1 // UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -*- C++ -*-=//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This checker detects blocks that capture uninitialized values.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
15 #include "clang/AST/Attr.h"
16 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
17 #include "clang/StaticAnalyzer/Core/Checker.h"
18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
21 #include "llvm/ADT/SmallString.h"
22 #include "llvm/Support/raw_ostream.h"
23
24 using namespace clang;
25 using namespace ento;
26
27 namespace {
28 class UndefCapturedBlockVarChecker
29 : public Checker< check::PostStmt<BlockExpr> > {
30 mutable std::unique_ptr<BugType> BT;
31
32 public:
33 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
34 };
35 } // end anonymous namespace
36
37 static const DeclRefExpr *FindBlockDeclRefExpr(const Stmt *S,
38 const VarDecl *VD) {
39 if (const DeclRefExpr *BR = dyn_cast<DeclRefExpr>(S))
40 if (BR->getDecl() == VD)
41 return BR;
42
43 for (const Stmt *Child : S->children())
44 if (Child)
45 if (const DeclRefExpr *BR = FindBlockDeclRefExpr(Child, VD))
46 return BR;
47
48 return nullptr;
49 }
50
51 void
52 UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE,
53 CheckerContext &C) const {
54 if (!BE->getBlockDecl()->hasCaptures())
55 return;
56
57 ProgramStateRef state = C.getState();
58 auto *R = cast<BlockDataRegion>(C.getSVal(BE).getAsRegion());
59
60 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
61 E = R->referenced_vars_end();
62
63 for (; I != E; ++I) {
64 // This VarRegion is the region associated with the block; we need
65 // the one associated with the encompassing context.
66 const VarRegion *VR = I.getCapturedRegion();
67 const VarDecl *VD = VR->getDecl();
68
69 if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage())
70 continue;
71
72 // Get the VarRegion associated with VD in the local stack frame.
73 if (Optional<UndefinedVal> V =
74 state->getSVal(I.getOriginalRegion()).getAs<UndefinedVal>()) {
75 if (ExplodedNode *N = C.generateErrorNode()) {
76 if (!BT)
77 BT.reset(
78 new BuiltinBug(this, "uninitialized variable captured by block"));
79
80 // Generate a bug report.
81 SmallString<128> buf;
82 llvm::raw_svector_ostream os(buf);
83
84 os << "Variable '" << VD->getName()
85 << "' is uninitialized when captured by block";
86
87 auto R = llvm::make_unique<BugReport>(*BT, os.str(), N);
88 if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
89 R->addRange(Ex->getSourceRange());
90 R->addVisitor(llvm::make_unique<FindLastStoreBRVisitor>(
91 *V, VR, /*EnableNullFPSuppression*/ false));
92 R->disablePathPruning();
93 // need location of block
94 C.emitReport(std::move(R));
95 }
96 }
97 }
98 }
99
100 void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
101 mgr.registerChecker<UndefCapturedBlockVarChecker>();
102 }
ento
clang::BlockExpr::getBlockDecl
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5191
clang::BlockDecl::hasCaptures
bool hasCaptures() const
True if this block (or its nested blocks) captures anything of local storage from its enclosing scope...
Definition: Decl.h:3977
FindBlockDeclRefExpr
static const DeclRefExpr * FindBlockDeclRefExpr(const Stmt *S, const VarDecl *VD)
Definition: UndefCapturedBlockVarChecker.cpp:37
clang::Stmt
Stmt - This represents one statement.
Definition: Stmt.h:66
clang::ento::ProgramStateRef
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
Definition: ProgramState_Fwd.h:38
BugType.h
clang::VarDecl
Represents a variable declaration or definition.
Definition: Decl.h:813
ExprEngine.h
llvm::Optional
Definition: LLVM.h:38
Checker.h
CheckerManager.h
clang::CodeGen::state
i32 captured_struct **param SharedsTy A type which contains references the shared variables *param Shareds Context with the list of shared variables from the p *TaskFunction *param Data Additional data for task generation like final * state
Definition: CGOpenMPRuntime.h:748
clang::Stmt::children
child_range children()
Definition: Stmt.cpp:237
llvm::SmallString
Definition: LLVM.h:35
clang::BlockExpr::getBody
const Stmt * getBody() const
Definition: Expr.cpp:2140
clang::Decl::hasAttr
bool hasAttr() const
Definition: DeclBase.h:531
clang::Expr
This represents one expression.
Definition: Expr.h:106
clang::VarDecl::hasLocalStorage
bool hasLocalStorage() const
Returns true if a variable with function scope is a non-static local variable.
Definition: Decl.h:1036
clang::BlockExpr
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5177
BuiltinCheckerRegistration.h
Attr.h
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:22
clang::NamedDecl::getName
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:276
clang::DeclRefExpr
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1041
CheckerContext.h