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[analyzer] Extend EnumCastOutOfRange diagnostics #68191

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Merged
merged 4 commits into from
Oct 28, 2023
Merged

[analyzer] Extend EnumCastOutOfRange diagnostics #68191

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a08f511
[analyzer] Extend EnumCastOutOfRange diagnostics
Oct 4, 2023
b9807ec
Track expression value of the CastExpr
Oct 4, 2023
4d12939
add trackexpression test
Oct 24, 2023
af9baa2
Add test cases for anonymous enums
Oct 27, 2023
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40 changes: 29 additions & 11 deletions clang/lib/StaticAnalyzer/Checkers/EnumCastOutOfRangeChecker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,8 @@ class ConstraintBasedEQEvaluator {
// value can be matching.
class EnumCastOutOfRangeChecker : public Checker<check::PreStmt<CastExpr>> {
mutable std::unique_ptr<BugType> EnumValueCastOutOfRange;
void reportWarning(CheckerContext &C) const;
void reportWarning(CheckerContext &C, const CastExpr *CE,
const EnumDecl *E) const;

public:
void checkPreStmt(const CastExpr *CE, CheckerContext &C) const;
Expand All @@ -72,21 +73,38 @@ EnumValueVector getDeclValuesForEnum(const EnumDecl *ED) {
EnumValueVector DeclValues(
std::distance(ED->enumerator_begin(), ED->enumerator_end()));
llvm::transform(ED->enumerators(), DeclValues.begin(),
[](const EnumConstantDecl *D) { return D->getInitVal(); });
[](const EnumConstantDecl *D) { return D->getInitVal(); });
return DeclValues;
}
} // namespace

void EnumCastOutOfRangeChecker::reportWarning(CheckerContext &C) const {
void EnumCastOutOfRangeChecker::reportWarning(CheckerContext &C,
const CastExpr *CE,
const EnumDecl *E) const {
assert(E && "valid EnumDecl* is expected");
if (const ExplodedNode *N = C.generateNonFatalErrorNode()) {
if (!EnumValueCastOutOfRange)
EnumValueCastOutOfRange.reset(
new BugType(this, "Enum cast out of range"));
constexpr llvm::StringLiteral Msg =
"The value provided to the cast expression is not in the valid range"
" of values for the enum";
C.emitReport(std::make_unique<PathSensitiveBugReport>(
*EnumValueCastOutOfRange, Msg, N));

llvm::SmallString<128> Msg{"The value provided to the cast expression is "
"not in the valid range of values for "};
StringRef EnumName{E->getName()};
if (EnumName.empty()) {
Msg += "the enum";
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Could you add a testcase that shows an example where this branch is used? (Is this for the C-style typedef enum {...} foo_t; declarations?)

} else {
Msg += '\'';
Msg += EnumName;
Msg += '\'';
}

auto BR = std::make_unique<PathSensitiveBugReport>(*EnumValueCastOutOfRange,
Msg, N);
bugreporter::trackExpressionValue(N, CE->getSubExpr(), *BR);
BR->addNote("enum declared here",
PathDiagnosticLocation::create(E, C.getSourceManager()),
{E->getSourceRange()});
C.emitReport(std::move(BR));
}
}

Expand Down Expand Up @@ -138,13 +156,13 @@ void EnumCastOutOfRangeChecker::checkPreStmt(const CastExpr *CE,
return;

// Check if any of the enum values possibly match.
bool PossibleValueMatch = llvm::any_of(
DeclValues, ConstraintBasedEQEvaluator(C, *ValueToCast));
bool PossibleValueMatch =
llvm::any_of(DeclValues, ConstraintBasedEQEvaluator(C, *ValueToCast));

// If there is no value that can possibly match any of the enum values, then
// warn.
if (!PossibleValueMatch)
reportWarning(C);
reportWarning(C, CE, ED);
}

void ento::registerEnumCastOutOfRangeChecker(CheckerManager &mgr) {
Expand Down
44 changes: 38 additions & 6 deletions clang/test/Analysis/enum-cast-out-of-range.c
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Original file line number Diff line number Diff line change
@@ -1,7 +1,9 @@
// RUN: %clang_analyze_cc1 \
// RUN: -analyzer-checker=core,alpha.cplusplus.EnumCastOutOfRange \
// RUN: -analyzer-output text \
// RUN: -verify %s

// expected-note@+1 + {{enum declared here}}
enum En_t {
En_0 = -4,
En_1,
Expand All @@ -11,17 +13,23 @@ enum En_t {
};

void unscopedUnspecifiedCStyle(void) {
enum En_t Below = (enum En_t)(-5); // expected-warning {{not in the valid range}}
enum En_t Below = (enum En_t)(-5); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
enum En_t NegVal1 = (enum En_t)(-4); // OK.
enum En_t NegVal2 = (enum En_t)(-3); // OK.
enum En_t InRange1 = (enum En_t)(-2); // expected-warning {{not in the valid range}}
enum En_t InRange2 = (enum En_t)(-1); // expected-warning {{not in the valid range}}
enum En_t InRange3 = (enum En_t)(0); // expected-warning {{not in the valid range}}
enum En_t InRange1 = (enum En_t)(-2); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
enum En_t InRange2 = (enum En_t)(-1); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
enum En_t InRange3 = (enum En_t)(0); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
enum En_t PosVal1 = (enum En_t)(1); // OK.
enum En_t PosVal2 = (enum En_t)(2); // OK.
enum En_t InRange4 = (enum En_t)(3); // expected-warning {{not in the valid range}}
enum En_t InRange4 = (enum En_t)(3); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
enum En_t PosVal3 = (enum En_t)(4); // OK.
enum En_t Above = (enum En_t)(5); // expected-warning {{not in the valid range}}
enum En_t Above = (enum En_t)(5); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
}

enum En_t unused;
Expand All @@ -32,3 +40,27 @@ void unusedExpr(void) {
// generate a warning having nothing to do with this checker.
unused; // expected-warning {{expression result unused}}
}

// Test typedef-ed anonymous enums
typedef enum { // expected-note {{enum declared here}}
TD_0 = 0,
} TD_t;

void testTypeDefEnum(void) {
(void)(TD_t)(-1); // expected-warning {{not in the valid range of values for the enum}}
// expected-note@-1 {{not in the valid range of values for the enum}}
}

// Test expression tracking
void set(int* p, int v) {
*p = v; // expected-note {{The value -1 is assigned to 'i'}}
}


void testTrackExpression(int i) {
set(&i, -1); // expected-note {{Passing the value -1 via 2nd parameter 'v'}}
// expected-note@-1 {{Calling 'set'}}
// expected-note@-2 {{Returning from 'set'}}
(void)(enum En_t)(i); // expected-warning {{not in the valid range of values for 'En_t'}}
// expected-note@-1 {{not in the valid range of values for 'En_t'}}
}
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