88b56caa0e
Summary: Currently clang static analyzer does warn on: ``` int x; x+=1; x-=1; x=x+1; x=x-1; ``` But does warn on: ``` int x; x++; x--; --x; ++x; ``` This differential should fix that. Fixes https://bugs.llvm.org/show_bug.cgi?id=35419 Reviewers: dcoughlin, NoQ Reviewed By: dcoughlin Subscribers: NoQ, xazax.hun, szepet, cfe-commits, a.sidorin Tags: #clang Differential Revision: https://reviews.llvm.org/D40463 llvm-svn: 319411
105 lines
3.1 KiB
C++
105 lines
3.1 KiB
C++
//===--- UndefinedAssignmentChecker.h ---------------------------*- C++ -*--==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This defines UndefinedAssignmentChecker, a builtin check in ExprEngine that
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// checks for assigning undefined values.
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//
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//===----------------------------------------------------------------------===//
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#include "ClangSACheckers.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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using namespace clang;
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using namespace ento;
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namespace {
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class UndefinedAssignmentChecker
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: public Checker<check::Bind> {
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mutable std::unique_ptr<BugType> BT;
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public:
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void checkBind(SVal location, SVal val, const Stmt *S,
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CheckerContext &C) const;
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};
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}
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void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
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const Stmt *StoreE,
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CheckerContext &C) const {
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if (!val.isUndef())
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return;
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// Do not report assignments of uninitialized values inside swap functions.
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// This should allow to swap partially uninitialized structs
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// (radar://14129997)
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if (const FunctionDecl *EnclosingFunctionDecl =
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dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
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if (C.getCalleeName(EnclosingFunctionDecl) == "swap")
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return;
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ExplodedNode *N = C.generateErrorNode();
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if (!N)
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return;
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const char *str = "Assigned value is garbage or undefined";
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if (!BT)
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BT.reset(new BuiltinBug(this, str));
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// Generate a report for this bug.
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const Expr *ex = nullptr;
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while (StoreE) {
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if (const UnaryOperator *U = dyn_cast<UnaryOperator>(StoreE)) {
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str = "The expression is an uninitialized value. "
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"The computed value will also be garbage";
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ex = U->getSubExpr();
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break;
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}
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if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
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if (B->isCompoundAssignmentOp()) {
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ProgramStateRef state = C.getState();
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if (state->getSVal(B->getLHS(), C.getLocationContext()).isUndef()) {
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str = "The left expression of the compound assignment is an "
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"uninitialized value. The computed value will also be garbage";
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ex = B->getLHS();
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break;
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}
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}
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ex = B->getRHS();
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break;
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}
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if (const DeclStmt *DS = dyn_cast<DeclStmt>(StoreE)) {
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const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
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ex = VD->getInit();
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}
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break;
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}
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auto R = llvm::make_unique<BugReport>(*BT, str, N);
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if (ex) {
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R->addRange(ex->getSourceRange());
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bugreporter::trackNullOrUndefValue(N, ex, *R);
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}
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C.emitReport(std::move(R));
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}
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void ento::registerUndefinedAssignmentChecker(CheckerManager &mgr) {
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mgr.registerChecker<UndefinedAssignmentChecker>();
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}
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