martong updated this revision to Diff 244430.
martong added a comment.
- Rebase to master
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D73898/new/
https://reviews.llvm.org/D73898
Files:
clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
clang/test/Analysis/std-c-library-functions-arg-constraints.c
Index: clang/test/Analysis/std-c-library-functions-arg-constraints.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/std-c-library-functions-arg-constraints.c
@@ -0,0 +1,22 @@
+// RUN: %clang_analyze_cc1 %s \
+// RUN: -analyzer-checker=apiModeling.StdCLibraryFunctions \
+// RUN: -analyzer-checker=debug.ExprInspection \
+// RUN: -triple x86_64-unknown-linux-gnu
+
+void clang_analyzer_eval(int);
+
+int glob;
+
+typedef struct FILE FILE;
+#define EOF -1
+
+int isalnum(int);
+void test_alnum_concrete() {
+ int ret = isalnum(256); // expected-warning{{Function argument constraint is not satisfied}}
+ (void)ret;
+}
+void test_alnum_symbolic(int x) {
+ int ret = isalnum(x);
+ (void)ret;
+ clang_analyzer_eval(EOF <= x && x <= 255); // expected-warning{{TRUE}}
+}
Index: clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -51,6 +51,7 @@
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
@@ -61,7 +62,8 @@
using namespace clang::ento;
namespace {
-class StdLibraryFunctionsChecker : public Checker<check::PostCall, eval::Call> {
+class StdLibraryFunctionsChecker
+ : public Checker<check::PreCall, check::PostCall, eval::Call> {
/// Below is a series of typedefs necessary to define function specs.
/// We avoid nesting types here because each additional qualifier
/// would need to be repeated in every function spec.
@@ -142,6 +144,10 @@
const CallEvent &Call,
const Summary &Summary) const;
+ void checkAsWithinRange(ProgramStateRef State, const CallEvent &Call,
+ const Summary &Summary, const BugType &BT,
+ CheckerContext &C) const;
+
public:
ProgramStateRef apply(ProgramStateRef State, const CallEvent &Call,
const Summary &Summary) const {
@@ -155,6 +161,21 @@
}
llvm_unreachable("Unknown ValueRange kind!");
}
+
+ void check(ProgramStateRef State, const CallEvent &Call,
+ const Summary &Summary, const BugType &BT,
+ CheckerContext &C) const {
+ switch (Kind) {
+ case OutOfRange:
+ llvm_unreachable("Not implemented yet!");
+ case WithinRange:
+ checkAsWithinRange(State, Call, Summary, BT, C);
+ return;
+ case ComparesToArgument:
+ llvm_unreachable("Not implemented yet!");
+ }
+ llvm_unreachable("Unknown ValueRange kind!");
+ }
};
/// The complete list of ranges that defines a single branch.
@@ -163,10 +184,15 @@
using ArgTypes = std::vector<QualType>;
using Ranges = std::vector<ValueRangeSet>;
- /// Includes information about function prototype (which is necessary to
- /// ensure we're modeling the right function and casting values properly),
- /// approach to invalidation, and a list of branches - essentially, a list
- /// of list of ranges - essentially, a list of lists of lists of segments.
+ /// Includes information about
+ /// * function prototype (which is necessary to
+ /// ensure we're modeling the right function and casting values properly),
+ /// * approach to invalidation,
+ /// * a list of branches - a list of list of ranges -
+ /// i.e. a list of lists of lists of segments,
+ /// * a list of argument constraints, that must be true on every branch.
+ /// If these constraints are not satisfied that means a fatal error
+ /// usually resulting in undefined behaviour.
struct Summary {
const ArgTypes ArgTys;
const QualType RetTy;
@@ -181,6 +207,10 @@
Cases.push_back(VRS);
return *this;
}
+ Summary &ArgConstraint(ValueRange VR) {
+ ArgConstraints.push_back(VR);
+ return *this;
+ }
private:
static void assertTypeSuitableForSummary(QualType T) {
@@ -216,6 +246,8 @@
// lazily, and it doesn't change after initialization.
mutable llvm::StringMap<Summaries> FunctionSummaryMap;
+ BugType BT{this, "Unsatisfied argument constraints", categories::LogicError};
+
// Auxiliary functions to support ArgNo within all structures
// in a unified manner.
static QualType getArgType(const Summary &Summary, ArgNo ArgN) {
@@ -234,6 +266,7 @@
}
public:
+ void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
bool evalCall(const CallEvent &Call, CheckerContext &C) const;
@@ -353,6 +386,82 @@
return State;
}
+void StdLibraryFunctionsChecker::ValueRange::checkAsWithinRange(
+ ProgramStateRef State, const CallEvent &Call,
+ const Summary &Summary, const BugType &BT,
+ CheckerContext &C) const {
+
+ ProgramStateManager &Mgr = State->getStateManager();
+ SValBuilder &SVB = Mgr.getSValBuilder();
+ BasicValueFactory &BVF = SVB.getBasicValueFactory();
+ QualType T = getArgType(Summary, getArgNo());
+ SVal V = getArgSVal(Call, getArgNo());
+ switch (V.getSubKind()) {
+ default:
+ // FIXME Handle other cases.
+ return;
+ case nonloc::ConcreteIntKind: {
+
+ const IntRangeVector &R = getRanges();
+ size_t E = R.size();
+
+ const llvm::APSInt &Left = BVF.getValue(R[0].first - 1ULL, T);
+ const llvm::APSInt &Right = BVF.getValue(R[E - 1].second + 1ULL, T);
+ assert(Left <= Right);
+
+ // Out of range.
+ const llvm::APSInt &IntVal = V.castAs<nonloc::ConcreteInt>().getValue();
+ if (IntVal <= Left || IntVal >= Right) {
+ if (ExplodedNode *N = C.generateErrorNode(State)) {
+ // FIXME Add detailed diagnostic.
+ std::string Msg = "Function argument constraint is not satisfied";
+ auto R = std::make_unique<PathSensitiveBugReport>(BT, Msg, N);
+ bugreporter::trackExpressionValue(N, Call.getArgExpr(0), *R);
+ C.emitReport(std::move(R));
+ }
+ }
+ for (size_t I = 1; I != E; ++I) {
+ const llvm::APSInt &Min = BVF.getValue(R[I - 1].second + 1ULL, T);
+ const llvm::APSInt &Max = BVF.getValue(R[I].first - 1ULL, T);
+ if (Min <= Max) {
+ if (IntVal >= Min || IntVal <= Max) {
+ if (ExplodedNode *N = C.generateErrorNode(State)) {
+ // FIXME Add detailed diagnostic.
+ std::string Msg = "Function argument constraint is not satisfied";
+ auto R = std::make_unique<PathSensitiveBugReport>(BT, Msg, N);
+ bugreporter::trackExpressionValue(N, Call.getArgExpr(0), *R);
+ C.emitReport(std::move(R));
+ }
+ }
+ }
+ }
+
+ }
+
+ } // end switch
+}
+
+void StdLibraryFunctionsChecker::checkPreCall(const CallEvent &Call,
+ CheckerContext &C) const {
+ const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
+ if (!FD)
+ return;
+
+ const CallExpr *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
+ if (!CE)
+ return;
+
+ Optional<Summary> FoundSummary = findFunctionSummary(FD, CE, C);
+ if (!FoundSummary)
+ return;
+
+ const Summary &Summary = *FoundSummary;
+ ProgramStateRef State = C.getState();
+ for (const auto &VR : Summary.ArgConstraints) {
+ VR.check(State, Call, Summary, BT, C);
+ }
+}
+
void StdLibraryFunctionsChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
@@ -380,6 +489,11 @@
break;
}
+ // Apply argument constraints as well.
+ for (const auto &VR : Summary.ArgConstraints)
+ if (NewState)
+ NewState = VR.apply(NewState, Call, Summary);
+
if (NewState && NewState != State)
C.addTransition(NewState);
}
@@ -569,7 +683,6 @@
auto IsLessThan = [](ArgNo ArgN) { return IntRangeVector{{BO_LE, ArgN}}; };
using RetType = QualType;
-
// Templates for summaries that are reused by many functions.
auto Getc = [&]() {
return Summary(ArgTypes{Irrelevant}, RetType{IntTy}, NoEvalCall)
@@ -597,6 +710,9 @@
FunctionSummaryMap = {
// The isascii() family of functions.
+ // The behavior is undefined if the value of the argument is not
+ // representable as unsigned char or is not equal to EOF. See e.g. C99
+ // 7.4.1.2 The isalpha function (p: 181-182).
{
"isalnum",
Summaries{
@@ -615,7 +731,9 @@
{'A', 'Z'},
{'a', 'z'},
{128, UCharMax}}),
- ReturnValueCondition(WithinRange, SingleValue(0))})},
+ ReturnValueCondition(WithinRange, SingleValue(0))})
+ .ArgConstraint(ArgumentCondition(
+ 0U, WithinRange, {{EOFv, EOFv}, {0, UCharMax}}))},
},
{
"isalpha",
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