1//===- unittests/StaticAnalyzer/SValSimplifyerTest.cpp --------------------===//
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#include "CheckerRegistration.h"
10#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
11#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
12#include "clang/StaticAnalyzer/Core/Checker.h"
13#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
14#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
15#include "clang/StaticAnalyzer/Frontend/AnalysisConsumer.h"
16#include "clang/StaticAnalyzer/Frontend/CheckerRegistry.h"
17#include "llvm/ADT/Twine.h"
18#include "llvm/Support/raw_ostream.h"
19#include "gtest/gtest.h"
20
21using namespace clang;
22using namespace ento;
23
24static std::string toString(SVal V) {
25 std::string Result;
26 llvm::raw_string_ostream Stream(Result);
27 V.dumpToStream(OS&: Stream);
28 return Result;
29}
30
31static void replace(std::string &Content, StringRef Substr,
32 StringRef Replacement) {
33 std::size_t Pos = 0;
34 while ((Pos = Content.find(svt: Substr, pos: Pos)) != std::string::npos) {
35 Content.replace(pos: Pos, n: Substr.size(), svt: Replacement);
36 Pos += Replacement.size();
37 }
38}
39
40namespace {
41
42class SimplifyChecker : public Checker<check::PreCall> {
43 const BugType Bug{this, "SimplifyChecker"};
44 const CallDescription SimplifyCall{CDM::SimpleFunc, {"simplify"}, 1};
45
46 void report(CheckerContext &C, const Expr *E, StringRef Description) const {
47 PathDiagnosticLocation Loc(E->getExprLoc(), C.getSourceManager());
48 auto Report = std::make_unique<BasicBugReport>(args: Bug, args&: Description, args&: Loc);
49 C.emitReport(R: std::move(Report));
50 }
51
52public:
53 void checkPreCall(const CallEvent &Call, CheckerContext &C) const {
54 if (!SimplifyCall.matches(Call))
55 return;
56 const Expr *Arg = Call.getArgExpr(Index: 0);
57 SVal Val = C.getSVal(Arg);
58 SVal SimplifiedVal = C.getSValBuilder().simplifySVal(State: C.getState(), Val);
59 std::string Subject = toString(V: Val);
60 std::string Simplified = toString(V: SimplifiedVal);
61 std::string Message = (llvm::Twine{Subject} + " -> " + Simplified).str();
62 report(C, E: Arg, Description: Message);
63 }
64};
65} // namespace
66
67static void addSimplifyChecker(AnalysisASTConsumer &AnalysisConsumer,
68 AnalyzerOptions &AnOpts) {
69 AnOpts.CheckersAndPackages = {{"SimplifyChecker", true}};
70 AnalysisConsumer.AddCheckerRegistrationFn(Fn: [](CheckerRegistry &Registry) {
71 Registry.addChecker<SimplifyChecker>(FullName: "SimplifyChecker", Desc: "EmptyDescription",
72 DocsUri: "EmptyDocsUri");
73 });
74}
75
76static void runThisCheckerOnCode(const std::string &Code, std::string &Diags) {
77 ASSERT_TRUE(runCheckerOnCode<addSimplifyChecker>(Code, Diags,
78 /*OnlyEmitWarnings=*/true));
79 ASSERT_FALSE(Diags.empty());
80 ASSERT_EQ(Diags.back(), '\n');
81 Diags.pop_back();
82}
83
84namespace {
85
86TEST(SValSimplifyerTest, LHSConstrainedNullPtrDiff) {
87 constexpr auto Code = R"cpp(
88template <class T> void simplify(T);
89void LHSConstrainedNullPtrDiff(char *p, char *q) {
90 int diff = p - q;
91 if (!p)
92 simplify(diff);
93})cpp";
94
95 std::string Diags;
96 runThisCheckerOnCode(Code, Diags);
97 replace(Content&: Diags, Substr: "(reg_$0<char * p>)", Replacement: "reg_p");
98 replace(Content&: Diags, Substr: "(reg_$1<char * q>)", Replacement: "reg_q");
99 // This should not be simplified to "Unknown".
100 EXPECT_EQ(Diags, "SimplifyChecker: reg_p - reg_q -> 0U - reg_q");
101}
102
103} // namespace
104

source code of clang/unittests/StaticAnalyzer/SValSimplifyerTest.cpp