JonasToth updated this revision to Diff 296549.
JonasToth added a comment.
rebase to newest expmutanalyzer patch
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D54943/new/
https://reviews.llvm.org/D54943
Files:
clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp
clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.h
clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-const-correctness.rst
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-cxx17.cpp
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-pointer-as-values.cpp
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-pointer-as-values.cpp
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-values.cpp
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-values.cpp
clang/lib/Analysis/ExprMutationAnalyzer.cpp
clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
Index: clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
===================================================================
--- clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
+++ clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp
@@ -19,9 +19,7 @@
using namespace clang::ast_matchers;
using ::testing::ElementsAre;
-using ::testing::IsEmpty;
using ::testing::ResultOf;
-using ::testing::StartsWith;
using ::testing::Values;
namespace {
@@ -63,12 +61,16 @@
const auto *const S = selectFirst<Stmt>("stmt", Results);
SmallVector<std::string, 1> Chain;
ExprMutationAnalyzer Analyzer(*S, AST->getASTContext());
+
for (const auto *E = selectFirst<Expr>("expr", Results); E != nullptr;) {
const Stmt *By = Analyzer.findMutation(E);
- std::string buffer;
- llvm::raw_string_ostream stream(buffer);
- By->printPretty(stream, nullptr, AST->getASTContext().getPrintingPolicy());
- Chain.push_back(StringRef(stream.str()).trim().str());
+ if (!By)
+ break;
+
+ std::string Buffer;
+ llvm::raw_string_ostream Stream(Buffer);
+ By->printPretty(Stream, nullptr, AST->getASTContext().getPrintingPolicy());
+ Chain.emplace_back(StringRef(Stream.str()).trim().str());
E = dyn_cast<DeclRefExpr>(By);
}
return Chain;
@@ -111,7 +113,13 @@
class AssignmentTest : public ::testing::TestWithParam<std::string> {};
+// This test is for the most basic and direct modification of a variable,
+// assignment to it (e.g. `x = 10;`).
+// It additionally tests, that reference to a variable are not only captured
+// directly, but expression that result in the variable are handled, too.
+// This includes the comma operator, parens and the ternary operator.
TEST_P(AssignmentTest, AssignmentModifies) {
+ // Test the detection of the raw expression modifications.
{
const std::string ModExpr = "x " + GetParam() + " 10";
const auto AST = buildASTFromCode("void f() { int x; " + ModExpr + "; }");
@@ -120,6 +128,7 @@
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
}
+ // Test the detection if the expression is surrounded by parens.
{
const std::string ModExpr = "(x) " + GetParam() + " 10";
const auto AST = buildASTFromCode("void f() { int x; " + ModExpr + "; }");
@@ -127,12 +136,79 @@
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
}
+
+ // Test the detection if the comma operator yields the expression as result.
+ {
+ const std::string ModExpr = "x " + GetParam() + " 10";
+ const auto AST = buildASTFromCodeWithArgs(
+ "void f() { int x, y; y, " + ModExpr + "; }", {"-Wno-unused-value"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
+ }
+
+ // Ensure no detection if t he comma operator does not yield the expression as
+ // result.
+ {
+ const std::string ModExpr = "y, x, y " + GetParam() + " 10";
+ const auto AST = buildASTFromCodeWithArgs(
+ "void f() { int x, y; " + ModExpr + "; }", {"-Wno-unused-value"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_FALSE(isMutated(Results, AST.get()));
+ }
+
+ // Test the detection if the a ternary operator can result in the expression.
+ {
+ const std::string ModExpr = "(y != 0 ? y : x) " + GetParam() + " 10";
+ const auto AST =
+ buildASTFromCode("void f() { int y = 0, x; " + ModExpr + "; }");
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
+ }
+
+ // Test the detection if the a ternary operator can result in the expression
+ // through multiple nesting of ternary operators.
+ {
+ const std::string ModExpr =
+ "(y != 0 ? (y > 5 ? y : x) : (y)) " + GetParam() + " 10";
+ const auto AST =
+ buildASTFromCode("void f() { int y = 0, x; " + ModExpr + "; }");
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
+ }
+
+ // Test the detection if the a ternary operator can result in the expression
+ // with additional parens.
+ {
+ const std::string ModExpr = "(y != 0 ? (y) : ((x))) " + GetParam() + " 10";
+ const auto AST =
+ buildASTFromCode("void f() { int y = 0, x; " + ModExpr + "; }");
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre(ModExpr));
+ }
}
INSTANTIATE_TEST_CASE_P(AllAssignmentOperators, AssignmentTest,
Values("=", "+=", "-=", "*=", "/=", "%=", "&=", "|=",
"^=", "<<=", ">>="), );
+TEST(ExprMutationAnalyzerTest, AssignmentConditionalWithInheritance) {
+ const auto AST = buildASTFromCode("struct Base {void nonconst(); };"
+ "struct Derived : Base {};"
+ "static void f() {"
+ " Derived x, y;"
+ " Base &b = true ? x : y;"
+ " b.nonconst();"
+ "}");
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("b", "b.nonconst()"));
+}
+
class IncDecTest : public ::testing::TestWithParam<std::string> {};
TEST_P(IncDecTest, IncDecModifies) {
@@ -147,6 +223,8 @@
Values("++x", "--x", "x++", "x--", "++(x)", "--(x)",
"(x)++", "(x)--"), );
+// Section: member functions
+
TEST(ExprMutationAnalyzerTest, NonConstMemberFunc) {
const auto AST = buildASTFromCode(
"void f() { struct Foo { void mf(); }; Foo x; x.mf(); }");
@@ -185,6 +263,18 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+TEST(ExprMutationAnalyzerTest, TypeDependentMemberCall) {
+ const auto AST = buildASTFromCodeWithArgs(
+ "template <class T> class vector { void push_back(T); }; "
+ "template <class T> void f() { vector<T> x; x.push_back(T()); }",
+ {"-fno-delayed-template-parsing"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("x.push_back(T())"));
+}
+
+// Section: overloaded operators
+
TEST(ExprMutationAnalyzerTest, NonConstOperator) {
const auto AST = buildASTFromCode(
"void f() { struct Foo { Foo& operator=(int); }; Foo x; x = 10; }");
@@ -201,6 +291,19 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+TEST(ExprMutationAnalyzerTest, UnresolvedOperator) {
+ const auto AST = buildASTFromCodeWithArgs(
+ "template <typename Stream> void input_operator_template() {"
+ "Stream x; unsigned y = 42;"
+ "x >> y; }",
+ {"-fno-delayed-template-parsing"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_TRUE(isMutated(Results, AST.get()));
+}
+
+// Section: expression as call argument
+
TEST(ExprMutationAnalyzerTest, ByValueArgument) {
auto AST = buildASTFromCode("void g(int); void f() { int x; g(x); }");
auto Results =
@@ -322,6 +425,49 @@
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("A<0>::mf(x)"));
}
+TEST(ExprMutationAnalyzerTest, ByNonConstRefArgumentFunctionTypeDependent) {
+#if 1
+ // This testcase did not actually reproduce a problem. Maybe the second one
+ // points to the same issue!
+ auto AST = buildASTFromCode(
+ "template <typename CBTy> static void foreachUse(CBTy CB) {"
+ " int array[4] = {1, 2, 3, 4};"
+ " for (unsigned idx = 0; idx < 4; ++idx) {"
+ " int &x = array[idx];"
+ " CB(x);"
+ " }"
+ "}"
+ "void usage1() {"
+ " auto const_lambda = [](int arg) { (void) arg; };"
+ " foreachUse(const_lambda);"
+ "}"
+ "void usage2() {"
+ " int number = 42;"
+ " auto mod_lambda = [&](int& arg) { arg+= number; };"
+ " foreachUse(mod_lambda);"
+ "}"
+ );
+ auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("CB(x)"));
+#endif
+
+#if 1
+ AST = buildASTFromCodeWithArgs(
+ "enum MyEnum { foo, bar };"
+ "void tryParser(unsigned& first, MyEnum Type) { first++, (void)Type; }"
+ "template <MyEnum Type> void parse() {"
+ " auto parser = [](unsigned& first) { first++; tryParser(first, Type); };"
+ " unsigned x = 42;"
+ " parser(x);"
+ "}",
+ {"-fno-delayed-template-parsing"});
+ Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("parser(x)"));
+#endif
+}
+
TEST(ExprMutationAnalyzerTest, ByConstRefArgument) {
auto AST = buildASTFromCode("void g(const int&); void f() { int x; g(x); }");
auto Results =
@@ -394,24 +540,30 @@
"void g(const int&&); void f() { int x; g(static_cast<int&&>(x)); }");
auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<int &&>(x)"));
AST = buildASTFromCode("struct A {}; A operator+(const A&&, int);"
"void f() { A x; static_cast<A&&>(x) + 1; }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<A &&>(x)"));
AST = buildASTFromCode("void f() { struct A { A(const int&&); }; "
"int x; A y(static_cast<int&&>(x)); }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<int &&>(x)"));
AST = buildASTFromCode("void f() { struct A { A(); A(const A&&); }; "
"A x; A y(static_cast<A&&>(x)); }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<A &&>(x)"));
}
+// section: explicit std::move and std::forward testing
+
TEST(ExprMutationAnalyzerTest, Move) {
auto AST = buildASTFromCode(StdRemoveReference + StdMove +
"void f() { struct A {}; A x; std::move(x); }");
@@ -490,6 +642,9 @@
ElementsAre("std::forward<A &>(x) = y"));
}
+// section: template constellations that prohibit reasoning about modifications
+// as it depends on instantiations.
+
TEST(ExprMutationAnalyzerTest, CallUnresolved) {
auto AST =
buildASTFromCodeWithArgs("template <class T> void f() { T x; g(x); }",
@@ -543,6 +698,8 @@
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("T(x)"));
}
+// section: return values
+
TEST(ExprMutationAnalyzerTest, ReturnAsValue) {
auto AST = buildASTFromCode("int f() { int x; return x; }");
auto Results =
@@ -579,7 +736,7 @@
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()),
- ElementsAre("return static_cast<int &&>(x);"));
+ ElementsAre("static_cast<int &&>(x)"));
}
TEST(ExprMutationAnalyzerTest, ReturnAsConstRRef) {
@@ -587,9 +744,12 @@
"const int&& f() { int x; return static_cast<int&&>(x); }");
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<int &&>(x)"));
}
+// section: taking the address of a variable and pointers
+
TEST(ExprMutationAnalyzerTest, TakeAddress) {
const auto AST = buildASTFromCode("void g(int*); void f() { int x; g(&x); }");
const auto Results =
@@ -621,6 +781,9 @@
EXPECT_THAT(mutatedBy(ResultsY, AST.get()), ElementsAre("y"));
}
+// section: special case: all created references are non-mutating themself
+// and therefore all become 'const'/the value is not modified!
+
TEST(ExprMutationAnalyzerTest, FollowRefModified) {
auto AST = buildASTFromCode(
"void f() { int x; int& r0 = x; int& r1 = r0; int& r2 = r1; "
@@ -792,6 +955,8 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+// section: builtin arrays
+
TEST(ExprMutationAnalyzerTest, ArrayElementModified) {
const auto AST = buildASTFromCode("void f() { int x[2]; x[0] = 10; }");
const auto Results =
@@ -806,6 +971,8 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+// section: member modifications
+
TEST(ExprMutationAnalyzerTest, NestedMemberModified) {
auto AST =
buildASTFromCode("void f() { struct A { int vi; }; struct B { A va; }; "
@@ -849,6 +1016,8 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+// section: casts
+
TEST(ExprMutationAnalyzerTest, CastToValue) {
const auto AST =
buildASTFromCode("void f() { int x; static_cast<double>(x); }");
@@ -863,13 +1032,13 @@
auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()),
- ElementsAre("static_cast<int &>(x) = 10"));
+ ElementsAre("static_cast<int &>(x)"));
AST = buildASTFromCode("typedef int& IntRef;"
"void f() { int x; static_cast<IntRef>(x) = 10; }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
EXPECT_THAT(mutatedBy(Results, AST.get()),
- ElementsAre("static_cast<IntRef>(x) = 10"));
+ ElementsAre("static_cast<IntRef>(x)"));
}
TEST(ExprMutationAnalyzerTest, CastToRefNotModified) {
@@ -877,7 +1046,8 @@
buildASTFromCode("void f() { int x; static_cast<int&>(x); }");
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("static_cast<int &>(x)"));
}
TEST(ExprMutationAnalyzerTest, CastToConstRef) {
@@ -893,6 +1063,8 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+// section: comma expressions
+
TEST(ExprMutationAnalyzerTest, CommaExprWithAnAssigment) {
const auto AST = buildASTFromCodeWithArgs(
"void f() { int x; int y; (x, y) = 5; }", {"-Wno-unused-value"});
@@ -1019,6 +1191,18 @@
EXPECT_TRUE(isMutated(Results, AST.get()));
}
+TEST(ExprMutationAnalyzerTest, CommaNestedConditional) {
+ const std::string Code = "void f() { int x, y = 42;"
+ " y, (true ? x : y) = 42; }";
+ const auto AST = buildASTFromCodeWithArgs(Code, {"-Wno-unused-value"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("(true ? x : y) = 42"));
+}
+
+// section: lambda captures
+
TEST(ExprMutationAnalyzerTest, LambdaDefaultCaptureByValue) {
const auto AST = buildASTFromCode("void f() { int x; [=]() { x; }; }");
const auto Results =
@@ -1049,25 +1233,29 @@
ElementsAre(ResultOf(removeSpace, "[&x](){x=10;}")));
}
+// section: range-for loops
+
TEST(ExprMutationAnalyzerTest, RangeForArrayByRefModified) {
auto AST =
buildASTFromCode("void f() { int x[2]; for (int& e : x) e = 10; }");
auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("e", "e = 10"));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("for (int &e : x)\n e = 10;"));
AST = buildASTFromCode("typedef int& IntRef;"
"void f() { int x[2]; for (IntRef e : x) e = 10; }");
Results = match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("e", "e = 10"));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("for (IntRef e : x)\n e = 10;"));
}
-TEST(ExprMutationAnalyzerTest, RangeForArrayByRefNotModified) {
+TEST(ExprMutationAnalyzerTest, RangeForArrayByRefModifiedByImplicitInit) {
const auto AST =
buildASTFromCode("void f() { int x[2]; for (int& e : x) e; }");
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_TRUE(isMutated(Results, AST.get()));
}
TEST(ExprMutationAnalyzerTest, RangeForArrayByValue) {
@@ -1107,7 +1295,8 @@
"void f() { V x; for (int& e : x) e = 10; }");
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("e", "e = 10"));
+ EXPECT_THAT(mutatedBy(Results, AST.get()),
+ ElementsAre("for (int &e : x)\n e = 10;"));
}
TEST(ExprMutationAnalyzerTest, RangeForNonArrayByRefNotModified) {
@@ -1115,7 +1304,7 @@
"void f() { V x; for (int& e : x) e; }");
const auto Results =
match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
- EXPECT_FALSE(isMutated(Results, AST.get()));
+ EXPECT_TRUE(isMutated(Results, AST.get()));
}
TEST(ExprMutationAnalyzerTest, RangeForNonArrayByValue) {
@@ -1136,6 +1325,8 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+// section: unevaluated expressions
+
TEST(ExprMutationAnalyzerTest, UnevaluatedExpressions) {
auto AST = buildASTFromCode("void f() { int x, y; decltype(x = 10) z = y; }");
auto Results =
@@ -1189,6 +1380,8 @@
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("x.f()"));
}
+// section: special case: smartpointers
+
TEST(ExprMutationAnalyzerTest, UniquePtr) {
const std::string UniquePtrDef =
"template <class T> struct UniquePtr {"
@@ -1246,6 +1439,24 @@
EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("x->mf()"));
}
+// section: complex problems detected on real code
+
+TEST(ExprMutationAnalyzerTest, UnevaluatedContext) {
+ const std::string Example =
+ "template <typename T>"
+ "struct to_construct : T { to_construct(int &j) {} };"
+ "template <typename T>"
+ "void placement_new_in_unique_ptr() { int x = 0;"
+ " new to_construct<T>(x);"
+ "}";
+ auto AST =
+ buildASTFromCodeWithArgs(Example, {"-fno-delayed-template-parsing"});
+ auto Results =
+ match(withEnclosingCompound(declRefTo("x")), AST->getASTContext());
+ EXPECT_TRUE(isMutated(Results, AST.get()));
+ EXPECT_THAT(mutatedBy(Results, AST.get()), ElementsAre("(x)"));
+}
+
TEST(ExprMutationAnalyzerTest, ReproduceFailureMinimal) {
const std::string Reproducer =
"namespace std {"
Index: clang/lib/Analysis/ExprMutationAnalyzer.cpp
===================================================================
--- clang/lib/Analysis/ExprMutationAnalyzer.cpp
+++ clang/lib/Analysis/ExprMutationAnalyzer.cpp
@@ -6,7 +6,10 @@
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/OperationKinds.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
#include "llvm/ADT/STLExtras.h"
namespace clang {
@@ -24,11 +27,11 @@
return InnerMatcher.matches(*Range, Finder, Builder);
}
-AST_MATCHER_P(Expr, maybeEvalCommaExpr,
- ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
- const Expr* Result = &Node;
+AST_MATCHER_P(Expr, maybeEvalCommaExpr, ast_matchers::internal::Matcher<Expr>,
+ InnerMatcher) {
+ const Expr *Result = &Node;
while (const auto *BOComma =
- dyn_cast_or_null<BinaryOperator>(Result->IgnoreParens())) {
+ dyn_cast_or_null<BinaryOperator>(Result->IgnoreParens())) {
if (!BOComma->isCommaOp())
break;
Result = BOComma->getRHS();
@@ -36,6 +39,52 @@
return InnerMatcher.matches(*Result, Finder, Builder);
}
+AST_MATCHER_P(Expr, canResolveToExpr, ast_matchers::internal::Matcher<Expr>,
+ InnerMatcher) {
+ auto DerivedToBase = [](const ast_matchers::internal::Matcher<Expr> &Inner) {
+ return implicitCastExpr(anyOf(hasCastKind(CK_DerivedToBase),
+ hasCastKind(CK_UncheckedDerivedToBase)),
+ hasSourceExpression(Inner));
+ };
+ // Matches unless the value is a derived class and is assigned to a
+ // reference to the base class. Other implicit casts should not happen.
+ auto IgnoreDerivedToBase =
+ [&DerivedToBase](const ast_matchers::internal::Matcher<Expr> &Inner) {
+ return ignoringParens(expr(anyOf(Inner, DerivedToBase(Inner))));
+ };
+
+ // The 'ConditionalOperator' matches on `<anything> ? <expr> : <expr>`.
+ // This matching must be recursive, because <expr> can be anything resolving
+ // to the `InnerMatcher`, for example another conditional operator.
+ // The edge-case `BaseClass &b = <cond> ? DerivedVar1 : DerivedVar2;`
+ // is handled, too. The implicit cast happens outside of the conditional.
+ // This is matched by `DerivedToBase(canResolveToExpr(InnerMatcher))` below.
+ auto const ConditionalOperator = conditionalOperator(anyOf(
+ hasTrueExpression(ignoringParens(canResolveToExpr(InnerMatcher))),
+ hasFalseExpression(ignoringParens(canResolveToExpr(InnerMatcher)))));
+
+ auto const ComplexMatcher = ignoringParens(
+ expr(anyOf(IgnoreDerivedToBase(InnerMatcher),
+ maybeEvalCommaExpr(IgnoreDerivedToBase(InnerMatcher)),
+ IgnoreDerivedToBase(ConditionalOperator))));
+
+ return ComplexMatcher.matches(Node, Finder, Builder);
+}
+
+// Similar to 'hasAnyArgument', but does not work because 'InitListExpr' does
+// not have the 'arguments()' method.
+AST_MATCHER_P(InitListExpr, hasAnyInit, ast_matchers::internal::Matcher<Expr>,
+ InnerMatcher) {
+ for (const Expr *Arg : Node.inits()) {
+ ast_matchers::internal::BoundNodesTreeBuilder Result(*Builder);
+ if (InnerMatcher.matches(*Arg, Finder, &Result)) {
+ *Builder = std::move(Result);
+ return true;
+ }
+ }
+ return false;
+}
+
const ast_matchers::internal::VariadicDynCastAllOfMatcher<Stmt, CXXTypeidExpr>
cxxTypeidExpr;
@@ -151,7 +200,7 @@
NodeID<Expr>::value,
match(
findAll(
- expr(equalsNode(Exp),
+ expr(canResolveToExpr(equalsNode(Exp)),
anyOf(
// `Exp` is part of the underlying expression of
// decltype/typeof if it has an ancestor of
@@ -202,29 +251,43 @@
const Stmt *ExprMutationAnalyzer::findDirectMutation(const Expr *Exp) {
// LHS of any assignment operators.
const auto AsAssignmentLhs = binaryOperator(
- isAssignmentOperator(),
- hasLHS(maybeEvalCommaExpr(ignoringParenImpCasts(equalsNode(Exp)))));
+ isAssignmentOperator(), hasLHS(canResolveToExpr(equalsNode(Exp))));
// Operand of increment/decrement operators.
const auto AsIncDecOperand =
unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
- hasUnaryOperand(maybeEvalCommaExpr(
- ignoringParenImpCasts(equalsNode(Exp)))));
+ hasUnaryOperand(canResolveToExpr(equalsNode(Exp))));
// Invoking non-const member function.
// A member function is assumed to be non-const when it is unresolved.
const auto NonConstMethod = cxxMethodDecl(unless(isConst()));
- const auto AsNonConstThis =
- expr(anyOf(cxxMemberCallExpr(callee(NonConstMethod),
- on(maybeEvalCommaExpr(equalsNode(Exp)))),
- cxxOperatorCallExpr(callee(NonConstMethod),
- hasArgument(0,
- maybeEvalCommaExpr(equalsNode(Exp)))),
- callExpr(callee(expr(anyOf(
- unresolvedMemberExpr(
- hasObjectExpression(maybeEvalCommaExpr(equalsNode(Exp)))),
- cxxDependentScopeMemberExpr(
- hasObjectExpression(maybeEvalCommaExpr(equalsNode(Exp))))))))));
+
+ const auto AsNonConstThis = expr(anyOf(
+ cxxMemberCallExpr(callee(NonConstMethod),
+ on(canResolveToExpr(equalsNode(Exp)))),
+ cxxOperatorCallExpr(callee(NonConstMethod),
+ hasArgument(0, canResolveToExpr(equalsNode(Exp)))),
+ // In case of a templated type, calling overloaded operators is not
+ // resolved and modelled as `binaryOperator` on a dependent type.
+ // Such instances are considered a modification, because they can modify
+ // in different instantiations of the template.
+ binaryOperator(hasEitherOperand(
+ allOf(ignoringImpCasts(canResolveToExpr(equalsNode(Exp))),
+ isTypeDependent()))),
+ // Within class templates and member functions the member expression might
+ // not be resolved. In that case, the `callExpr` is considered to be a
+ // modification.
+ callExpr(
+ callee(expr(anyOf(unresolvedMemberExpr(hasObjectExpression(
+ canResolveToExpr(equalsNode(Exp)))),
+ cxxDependentScopeMemberExpr(hasObjectExpression(
+ canResolveToExpr(equalsNode(Exp)))))))),
+ // Match on a call to a know method, but the call itself is type
+ // dependent (e.g. `vector<T> v; v.push(T{});` in a templated function).
+ callExpr(allOf(isTypeDependent(),
+ callee(memberExpr(hasDeclaration(NonConstMethod),
+ hasObjectExpression(canResolveToExpr(
+ equalsNode(Exp)))))))));
// Taking address of 'Exp'.
// We're assuming 'Exp' is mutated as soon as its address is taken, though in
@@ -234,38 +297,59 @@
unaryOperator(hasOperatorName("&"),
// A NoOp implicit cast is adding const.
unless(hasParent(implicitCastExpr(hasCastKind(CK_NoOp)))),
- hasUnaryOperand(maybeEvalCommaExpr(equalsNode(Exp))));
+ hasUnaryOperand(canResolveToExpr(equalsNode(Exp))));
const auto AsPointerFromArrayDecay =
castExpr(hasCastKind(CK_ArrayToPointerDecay),
unless(hasParent(arraySubscriptExpr())),
- has(maybeEvalCommaExpr(equalsNode(Exp))));
+ has(canResolveToExpr(equalsNode(Exp))));
// Treat calling `operator->()` of move-only classes as taking address.
// These are typically smart pointers with unique ownership so we treat
// mutation of pointee as mutation of the smart pointer itself.
- const auto AsOperatorArrowThis =
- cxxOperatorCallExpr(hasOverloadedOperatorName("->"),
- callee(cxxMethodDecl(ofClass(isMoveOnly()),
- returns(nonConstPointerType()))),
- argumentCountIs(1),
- hasArgument(0, maybeEvalCommaExpr(equalsNode(Exp))));
+ const auto AsOperatorArrowThis = cxxOperatorCallExpr(
+ hasOverloadedOperatorName("->"),
+ callee(
+ cxxMethodDecl(ofClass(isMoveOnly()), returns(nonConstPointerType()))),
+ argumentCountIs(1), hasArgument(0, canResolveToExpr(equalsNode(Exp))));
// Used as non-const-ref argument when calling a function.
// An argument is assumed to be non-const-ref when the function is unresolved.
// Instantiated template functions are not handled here but in
// findFunctionArgMutation which has additional smarts for handling forwarding
// references.
- const auto NonConstRefParam = forEachArgumentWithParam(
- maybeEvalCommaExpr(equalsNode(Exp)),
- parmVarDecl(hasType(nonConstReferenceType())));
+ const auto NonConstRefParam = forEachArgumentWithParamType(
+ anyOf(canResolveToExpr(equalsNode(Exp)),
+ memberExpr(hasObjectExpression(canResolveToExpr(equalsNode(Exp))))),
+ nonConstReferenceType());
const auto NotInstantiated = unless(hasDeclaration(isInstantiated()));
+ const auto TypeDependentCallee = callee(
+ expr(anyOf(unresolvedLookupExpr(), unresolvedMemberExpr(),
+ cxxDependentScopeMemberExpr(), hasType(templateTypeParmType())
+#if 1
+ ,
+ isTypeDependent())));
+#else
+ ,
+ // Lambdas as type parameter are caught by this.
+ , ignoringParenImpCasts(declRefExpr(
+ to(varDecl(hasType(substTemplateTypeParmType()))))))));
+#endif
+
const auto AsNonConstRefArg = anyOf(
callExpr(NonConstRefParam, NotInstantiated),
cxxConstructExpr(NonConstRefParam, NotInstantiated),
- callExpr(callee(expr(anyOf(unresolvedLookupExpr(), unresolvedMemberExpr(),
- cxxDependentScopeMemberExpr(),
- hasType(templateTypeParmType())))),
- hasAnyArgument(maybeEvalCommaExpr(equalsNode(Exp)))),
- cxxUnresolvedConstructExpr(hasAnyArgument(maybeEvalCommaExpr(equalsNode(Exp)))));
+ callExpr(TypeDependentCallee,
+ hasAnyArgument(canResolveToExpr(equalsNode(Exp)))),
+ cxxUnresolvedConstructExpr(
+ hasAnyArgument(canResolveToExpr(equalsNode(Exp)))),
+ // Previous False Positive in the following Code:
+ // `template <typename T> void f() { int i = 42; new Type<T>(i); }`
+ // Where the constructor of `Type` takes its argument as reference.
+ // The AST does not resolve in a `cxxConstructExpr` because it is
+ // type-dependent.
+ parenListExpr(hasDescendant(expr(canResolveToExpr(equalsNode(Exp))))),
+ // If the initializer is for a reference type, there is no cast for
+ // the variable. Values are cast to RValue first.
+ initListExpr(hasAnyInit(expr(canResolveToExpr(equalsNode(Exp))))));
// Captured by a lambda by reference.
// If we're initializing a capture with 'Exp' directly then we're initializing
@@ -279,16 +363,24 @@
// For returning by const-ref there will be an ImplicitCastExpr <NoOp> (for
// adding const.)
const auto AsNonConstRefReturn = returnStmt(hasReturnValue(
- maybeEvalCommaExpr(equalsNode(Exp))));
+ anyOf(canResolveToExpr(equalsNode(Exp)),
+ castExpr(allOf(
+ hasCastKind(CK_DerivedToBase),
+ hasSourceExpression(canResolveToExpr(equalsNode(Exp))))))));
+
+ // It is used as a non-const-reference for initalizing a range-for loop.
+ const auto AsNonConstRefRangeInit = cxxForRangeStmt(
+ hasRangeInit(declRefExpr(allOf(canResolveToExpr(equalsNode(Exp)),
+ hasType(nonConstReferenceType())))));
const auto Matches = match(
- traverse(
- ast_type_traits::TK_AsIs,
- findAll(stmt(anyOf(AsAssignmentLhs, AsIncDecOperand, AsNonConstThis,
- AsAmpersandOperand, AsPointerFromArrayDecay,
- AsOperatorArrowThis, AsNonConstRefArg,
- AsLambdaRefCaptureInit, AsNonConstRefReturn))
- .bind("stmt"))),
+ traverse(ast_type_traits::TK_AsIs,
+ findAll(stmt(anyOf(AsAssignmentLhs, AsIncDecOperand,
+ AsNonConstThis, AsAmpersandOperand,
+ AsPointerFromArrayDecay, AsOperatorArrowThis,
+ AsNonConstRefArg, AsLambdaRefCaptureInit,
+ AsNonConstRefReturn, AsNonConstRefRangeInit))
+ .bind("stmt"))),
Stm, Context);
return selectFirst<Stmt>("stmt", Matches);
}
@@ -296,9 +388,10 @@
const Stmt *ExprMutationAnalyzer::findMemberMutation(const Expr *Exp) {
// Check whether any member of 'Exp' is mutated.
const auto MemberExprs =
- match(findAll(expr(anyOf(memberExpr(hasObjectExpression(equalsNode(Exp))),
- cxxDependentScopeMemberExpr(
- hasObjectExpression(equalsNode(Exp)))))
+ match(findAll(expr(anyOf(memberExpr(hasObjectExpression(
+ canResolveToExpr(equalsNode(Exp)))),
+ cxxDependentScopeMemberExpr(hasObjectExpression(
+ canResolveToExpr(equalsNode(Exp))))))
.bind(NodeID<Expr>::value)),
Stm, Context);
return findExprMutation(MemberExprs);
@@ -306,43 +399,112 @@
const Stmt *ExprMutationAnalyzer::findArrayElementMutation(const Expr *Exp) {
// Check whether any element of an array is mutated.
- const auto SubscriptExprs = match(
- findAll(arraySubscriptExpr(hasBase(ignoringImpCasts(equalsNode(Exp))))
- .bind(NodeID<Expr>::value)),
- Stm, Context);
+ const auto SubscriptExprs =
+ match(findAll(arraySubscriptExpr(
+ anyOf(hasBase(canResolveToExpr(equalsNode(Exp))),
+ hasBase(implicitCastExpr(
+ allOf(hasCastKind(CK_ArrayToPointerDecay),
+ hasSourceExpression(canResolveToExpr(
+ equalsNode(Exp))))))))
+ .bind(NodeID<Expr>::value)),
+ Stm, Context);
return findExprMutation(SubscriptExprs);
}
const Stmt *ExprMutationAnalyzer::findCastMutation(const Expr *Exp) {
+ // If the 'Exp' is explicitly casted to a non-const reference type the
+ // 'Exp' is considered to be modified.
+ const auto ExplicitCast = match(
+ findAll(
+ stmt(castExpr(hasSourceExpression(canResolveToExpr(equalsNode(Exp))),
+ explicitCastExpr(
+ hasDestinationType(nonConstReferenceType()))))
+ .bind("stmt")),
+ Stm, Context);
+
+ if (const auto *CastStmt = selectFirst<Stmt>("stmt", ExplicitCast))
+ return CastStmt;
+
// If 'Exp' is casted to any non-const reference type, check the castExpr.
- const auto Casts =
- match(findAll(castExpr(hasSourceExpression(equalsNode(Exp)),
- anyOf(explicitCastExpr(hasDestinationType(
- nonConstReferenceType())),
- implicitCastExpr(hasImplicitDestinationType(
- nonConstReferenceType()))))
- .bind(NodeID<Expr>::value)),
- Stm, Context);
+ const auto Casts = match(
+ findAll(
+ expr(castExpr(hasSourceExpression(canResolveToExpr(equalsNode(Exp))),
+ anyOf(explicitCastExpr(
+ hasDestinationType(nonConstReferenceType())),
+ implicitCastExpr(hasImplicitDestinationType(
+ nonConstReferenceType())))))
+ .bind(NodeID<Expr>::value)),
+ Stm, Context);
+
if (const Stmt *S = findExprMutation(Casts))
return S;
// Treat std::{move,forward} as cast.
const auto Calls =
match(findAll(callExpr(callee(namedDecl(
hasAnyName("::std::move", "::std::forward"))),
- hasArgument(0, equalsNode(Exp)))
+ hasArgument(0, canResolveToExpr(equalsNode(Exp))))
.bind("expr")),
Stm, Context);
return findExprMutation(Calls);
}
const Stmt *ExprMutationAnalyzer::findRangeLoopMutation(const Expr *Exp) {
+ // Keep the ordering for the specific initialization matches to happen first,
+ // because it is cheaper to match then all potential modifications of the
+ // loop variable.
+
+ // The range variable is a reference to a builtin array. In that case the
+ // array is considered modified if the loop-variable is a non-const reference.
+ const auto DeclStmtToNonRefToArray = declStmt(hasSingleDecl(varDecl(hasType(
+ hasUnqualifiedDesugaredType(referenceType(pointee(arrayType())))))));
+ const auto RefToArrayRefToElements = match(
+ findAll(stmt(cxxForRangeStmt(
+ hasLoopVariable(varDecl(hasType(nonConstReferenceType()))
+ .bind(NodeID<Decl>::value)),
+ hasRangeStmt(DeclStmtToNonRefToArray),
+ hasRangeInit(canResolveToExpr(equalsNode(Exp)))))
+ .bind("stmt")),
+ Stm, Context);
+
+ if (const auto *BadRangeInitFromArray =
+ selectFirst<Stmt>("stmt", RefToArrayRefToElements))
+ return BadRangeInitFromArray;
+
+ // Small helper to match special cases in range-for loops.
+ //
+ // It is possible that containers do not provide a const-overload for their
+ // iterator accessors. If this is the case, the variable is used non-const
+ // no matter what happens in the loop. This requires special detection as it
+ // is then faster to find all mutations of the loop variable.
+ // It aims at a different modification as well.
+ const auto HasAnyNonConstIterator =
+ anyOf(allOf(hasMethod(allOf(hasName("begin"), unless(isConst()))),
+ unless(hasMethod(allOf(hasName("begin"), isConst())))),
+ allOf(hasMethod(allOf(hasName("end"), unless(isConst()))),
+ unless(hasMethod(allOf(hasName("end"), isConst())))));
+
+ const auto DeclStmtToNonConstIteratorContainer = declStmt(
+ hasSingleDecl(varDecl(hasType(hasUnqualifiedDesugaredType(referenceType(
+ pointee(hasDeclaration(cxxRecordDecl(HasAnyNonConstIterator)))))))));
+
+ const auto RefToContainerBadIterators =
+ match(findAll(stmt(cxxForRangeStmt(allOf(
+ hasRangeStmt(DeclStmtToNonConstIteratorContainer),
+ hasRangeInit(canResolveToExpr(equalsNode(Exp))))))
+ .bind("stmt")),
+ Stm, Context);
+
+ if (const auto *BadIteratorsContainer =
+ selectFirst<Stmt>("stmt", RefToContainerBadIterators))
+ return BadIteratorsContainer;
+
// If range for looping over 'Exp' with a non-const reference loop variable,
// check all declRefExpr of the loop variable.
const auto LoopVars =
match(findAll(cxxForRangeStmt(
hasLoopVariable(varDecl(hasType(nonConstReferenceType()))
.bind(NodeID<Decl>::value)),
- hasRangeInit(equalsNode(Exp)))),
+ hasRangeInit(canResolveToExpr(equalsNode(Exp))))),
Stm, Context);
return findDeclMutation(LoopVars);
}
@@ -356,7 +518,8 @@
hasOverloadedOperatorName("*"),
callee(cxxMethodDecl(ofClass(isMoveOnly()),
returns(nonConstReferenceType()))),
- argumentCountIs(1), hasArgument(0, equalsNode(Exp)))
+ argumentCountIs(1),
+ hasArgument(0, canResolveToExpr(equalsNode(Exp))))
.bind(NodeID<Expr>::value)),
Stm, Context);
if (const Stmt *S = findExprMutation(Ref))
@@ -367,13 +530,12 @@
stmt(forEachDescendant(
varDecl(
hasType(nonConstReferenceType()),
- hasInitializer(anyOf(equalsNode(Exp),
- conditionalOperator(anyOf(
- hasTrueExpression(equalsNode(Exp)),
- hasFalseExpression(equalsNode(Exp)))))),
+ hasInitializer(anyOf(canResolveToExpr(equalsNode(Exp)),
+ memberExpr(hasObjectExpression(
+ canResolveToExpr(equalsNode(Exp)))))),
hasParent(declStmt().bind("stmt")),
- // Don't follow the reference in range statement, we've handled
- // that separately.
+ // Don't follow the reference in range statement, we've
+ // handled that separately.
unless(hasParent(declStmt(hasParent(
cxxForRangeStmt(hasRangeStmt(equalsBoundNode("stmt"))))))))
.bind(NodeID<Decl>::value))),
@@ -383,7 +545,7 @@
const Stmt *ExprMutationAnalyzer::findFunctionArgMutation(const Expr *Exp) {
const auto NonConstRefParam = forEachArgumentWithParam(
- equalsNode(Exp),
+ canResolveToExpr(equalsNode(Exp)),
parmVarDecl(hasType(nonConstReferenceType())).bind("parm"));
const auto IsInstantiated = hasDeclaration(isInstantiated());
const auto FuncDecl = hasDeclaration(functionDecl().bind("func"));
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-values.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-values.cpp
@@ -0,0 +1,957 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-const-correctness %t -- \
+// RUN: -config="{CheckOptions: [\
+// RUN: {key: 'cppcoreguidelines-const-correctness.TransformValues', value: 1}, \
+// RUN: {key: 'cppcoreguidelines-const-correctness.WarnPointersAsValues', value: 0}, \
+// RUN: {key: 'cppcoreguidelines-const-correctness.TransformPointersAsValues', value: 0}, \
+// RUN: ]}" --
+
+// ------- Provide test samples for primitive builtins ---------
+// - every 'p_*' variable is a 'potential_const_*' variable
+// - every 'np_*' variable is a 'non_potential_const_*' variable
+
+bool global;
+char np_global = 0; // globals can't be known to be const
+
+namespace foo {
+int scoped;
+float np_scoped = 1; // namespace variables are like globals
+} // namespace foo
+
+// Lambdas should be ignored, because they do not follow the normal variable
+// semantic (e.g. the type is only known to the compiler).
+void lambdas() {
+ auto Lambda = [](int i) { return i < 0; };
+}
+
+void some_function(double, wchar_t);
+
+void some_function(double np_arg0, wchar_t np_arg1) {
+ int p_local0 = 2;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+
+ int np_local0;
+ const int np_local1 = 42;
+
+ unsigned int np_local2 = 3;
+ np_local2 <<= 4;
+
+ int np_local3 = 4;
+ ++np_local3;
+ int np_local4 = 4;
+ np_local4++;
+
+ int np_local5 = 4;
+ --np_local5;
+ int np_local6 = 4;
+ np_local6--;
+}
+
+void nested_scopes() {
+ int p_local0 = 2;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ int np_local0 = 42;
+
+ {
+ int p_local1 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:5: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ np_local0 *= 2;
+ }
+}
+
+void ignore_reference_to_pointers() {
+ int *np_local0 = nullptr;
+ int *&np_local1 = np_local0;
+}
+
+void some_lambda_environment_capture_all_by_reference(double np_arg0) {
+ int np_local0 = 0;
+ int p_local0 = 1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+
+ int np_local2;
+ const int np_local3 = 2;
+
+ // Capturing all variables by reference prohibits making them const.
+ [&]() { ++np_local0; };
+
+ int p_local1 = 0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int' can be declared 'const'
+}
+
+void some_lambda_environment_capture_all_by_value(double np_arg0) {
+ int np_local0 = 0;
+ int p_local0 = 1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+
+ int np_local1;
+ const int np_local2 = 2;
+
+ // Capturing by value has no influence on them.
+ [=]() { (void)p_local0; };
+
+ np_local0 += 10;
+}
+
+void function_inout_pointer(int *inout);
+void function_in_pointer(const int *in);
+
+void some_pointer_taking(int *out) {
+ int np_local0 = 42;
+ const int *const p0_np_local0 = &np_local0;
+ int *const p1_np_local0 = &np_local0;
+
+ int np_local1 = 42;
+ const int *const p0_np_local1 = &np_local1;
+ int *const p1_np_local1 = &np_local1;
+ *p1_np_local0 = 43;
+
+ int np_local2 = 42;
+ function_inout_pointer(&np_local2);
+
+ // Prevents const.
+ int np_local3 = 42;
+ out = &np_local3; // This returns and invalid address, its just about the AST
+
+ int p_local1 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ const int *const p0_p_local1 = &p_local1;
+
+ int p_local2 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'int' can be declared 'const'
+ function_in_pointer(&p_local2);
+}
+
+void function_inout_ref(int &inout);
+void function_in_ref(const int &in);
+
+void some_reference_taking() {
+ int np_local0 = 42;
+ const int &r0_np_local0 = np_local0;
+ int &r1_np_local0 = np_local0;
+ r1_np_local0 = 43;
+ const int &r2_np_local0 = r1_np_local0;
+
+ int np_local1 = 42;
+ function_inout_ref(np_local1);
+
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ const int &r0_p_local0 = p_local0;
+
+ int p_local1 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ function_in_ref(p_local1);
+}
+
+double *non_const_pointer_return() {
+ double p_local0 = 0.0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
+ double np_local0 = 24.4;
+
+ return &np_local0;
+}
+
+const double *const_pointer_return() {
+ double p_local0 = 0.0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
+ double p_local1 = 24.4;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double' can be declared 'const'
+ return &p_local1;
+}
+
+double &non_const_ref_return() {
+ double p_local0 = 0.0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
+ double np_local0 = 42.42;
+ return np_local0;
+}
+
+const double &const_ref_return() {
+ double p_local0 = 0.0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
+ double p_local1 = 24.4;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double' can be declared 'const'
+ return p_local1;
+}
+
+double *&return_non_const_pointer_ref() {
+ double *np_local0 = nullptr;
+ return np_local0;
+}
+
+void overloaded_arguments(const int &in);
+void overloaded_arguments(int &inout);
+void overloaded_arguments(const int *in);
+void overloaded_arguments(int *inout);
+
+void function_calling() {
+ int np_local0 = 42;
+ overloaded_arguments(np_local0);
+
+ const int np_local1 = 42;
+ overloaded_arguments(np_local1);
+
+ int np_local2 = 42;
+ overloaded_arguments(&np_local2);
+
+ const int np_local3 = 42;
+ overloaded_arguments(&np_local3);
+}
+
+template <typename T>
+void define_locals(T np_arg0, T &np_arg1, int np_arg2) {
+ T np_local0 = 0;
+ np_local0 += np_arg0 * np_arg1;
+
+ T np_local1 = 42;
+ np_local0 += np_local1;
+
+ // Used as argument to an overloaded function with const and non-const.
+ T np_local2 = 42;
+ overloaded_arguments(np_local2);
+
+ int np_local4 = 42;
+ // non-template values are ok still.
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ np_local4 += p_local0;
+}
+
+template <typename T>
+void more_template_locals() {
+ const T np_local0 = {};
+ auto np_local1 = T{};
+ T &np_local2 = np_local1;
+ T *np_local_ptr = &np_local1;
+
+ const auto np_local3 = T{};
+ // FIXME: False positive, the reference points to a template type and needs
+ // to be excluded from analysis, but somehow isn't (matchers don't work)
+ auto &np_local4 = np_local3;
+
+ const auto *np_local5 = &np_local3;
+ auto *np_local6 = &np_local1;
+
+ using TypedefToTemplate = T;
+ TypedefToTemplate np_local7{};
+ // FIXME: False positive, the reference points to a template type and needs
+ // to be excluded from analysis, but somehow isn't (matchers don't work)
+ // auto &np_local8 = np_local7;
+ const auto &np_local9 = np_local7;
+ auto np_local10 = np_local7;
+ auto *np_local11 = &np_local10;
+ const auto *const np_local12 = &np_local10;
+
+ // FIXME: False positive, the reference points to a template type and needs
+ // to be excluded from analysis, but somehow isn't (matchers don't work)
+ // TypedefToTemplate &np_local13 = np_local7;
+ TypedefToTemplate *np_local14 = &np_local7;
+}
+
+void template_instantiation() {
+ const int np_local0 = 42;
+ int np_local1 = 42;
+
+ define_locals(np_local0, np_local1, np_local0);
+ define_locals(np_local1, np_local1, np_local1);
+ more_template_locals<int>();
+}
+
+struct ConstNonConstClass {
+ ConstNonConstClass();
+ ConstNonConstClass(double &np_local0);
+ double nonConstMethod() {}
+ double constMethod() const {}
+ double modifyingMethod(double &np_arg0) const;
+
+ double NonConstMember;
+ const double ConstMember;
+
+ double &NonConstMemberRef;
+ const double &ConstMemberRef;
+
+ double *NonConstMemberPtr;
+ const double *ConstMemberPtr;
+};
+
+void direct_class_access() {
+ ConstNonConstClass np_local0;
+
+ np_local0.constMethod();
+ np_local0.nonConstMethod();
+
+ ConstNonConstClass p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'ConstNonConstClass' can be declared 'const'
+ p_local0.constMethod();
+
+ ConstNonConstClass p_local1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'ConstNonConstClass' can be declared 'const'
+ double np_local1;
+ p_local1.modifyingMethod(np_local1);
+
+ double np_local2;
+ ConstNonConstClass p_local2(np_local2);
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'ConstNonConstClass' can be declared 'const'
+
+ ConstNonConstClass np_local3;
+ np_local3.NonConstMember = 42.;
+
+ ConstNonConstClass np_local4;
+ np_local4.NonConstMemberRef = 42.;
+
+ ConstNonConstClass p_local3;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'ConstNonConstClass' can be declared 'const'
+ const double val0 = p_local3.NonConstMember;
+ const double val1 = p_local3.NonConstMemberRef;
+ const double val2 = *p_local3.NonConstMemberPtr;
+
+ ConstNonConstClass p_local4;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local4' of type 'ConstNonConstClass' can be declared 'const'
+ *np_local4.NonConstMemberPtr = 42.;
+}
+
+void class_access_array() {
+ ConstNonConstClass np_local0[2];
+ np_local0[0].constMethod();
+ np_local0[1].constMethod();
+ np_local0[1].nonConstMethod();
+
+ ConstNonConstClass p_local0[2];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'ConstNonConstClass [2]' can be declared 'const'
+ p_local0[0].constMethod();
+ np_local0[1].constMethod();
+}
+
+struct OperatorsAsConstAsPossible {
+ OperatorsAsConstAsPossible &operator+=(const OperatorsAsConstAsPossible &rhs);
+ OperatorsAsConstAsPossible operator+(const OperatorsAsConstAsPossible &rhs) const;
+};
+
+struct NonConstOperators {
+};
+NonConstOperators operator+(NonConstOperators &lhs, NonConstOperators &rhs);
+NonConstOperators operator-(NonConstOperators lhs, NonConstOperators rhs);
+
+void internal_operator_calls() {
+ OperatorsAsConstAsPossible np_local0;
+ OperatorsAsConstAsPossible np_local1;
+ OperatorsAsConstAsPossible p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'OperatorsAsConstAsPossible' can be declared 'const'
+ OperatorsAsConstAsPossible p_local1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'OperatorsAsConstAsPossible' can be declared 'const'
+
+ np_local0 += p_local0;
+ np_local1 = p_local0 + p_local1;
+
+ NonConstOperators np_local2;
+ NonConstOperators np_local3;
+ NonConstOperators np_local4;
+
+ np_local2 = np_local3 + np_local4;
+
+ NonConstOperators p_local2;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'NonConstOperators' can be declared 'const'
+ NonConstOperators p_local3 = p_local2 - p_local2;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'NonConstOperators' can be declared 'const'
+}
+
+struct MyVector {
+ double *begin();
+ const double *begin() const;
+
+ double *end();
+ const double *end() const;
+
+ double &operator[](int index);
+ double operator[](int index) const;
+
+ double values[100];
+};
+
+void vector_usage() {
+ double np_local0[10];
+ np_local0[5] = 42.;
+
+ MyVector np_local1;
+ np_local1[5] = 42.;
+
+ double p_local0[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double [10]' can be declared 'const'
+ double p_local1 = p_local0[5];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double' can be declared 'const'
+
+ // The following subscript calls suprisingly choose the non-const operator
+ // version.
+ MyVector np_local2;
+ double p_local2 = np_local2[42];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'double' can be declared 'const'
+
+ MyVector np_local3;
+ const double np_local4 = np_local3[42];
+
+ // This subscript results in const overloaded operator.
+ const MyVector np_local5{};
+ double p_local3 = np_local5[42];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'double' can be declared 'const'
+}
+
+void const_handle(const double &np_local0);
+void const_handle(const double *np_local0);
+
+void non_const_handle(double &np_local0);
+void non_const_handle(double *np_local0);
+
+void handle_from_array() {
+ // Non-const handle from non-const array forbids declaring the array as const
+ double np_local0[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ double *p_local0 = &np_local0[1]; // Could be `double *const`, but warning deactivated by default
+
+ double np_local1[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ double &non_const_ref = np_local1[1];
+ non_const_ref = 42.;
+
+ double np_local2[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ double *np_local3;
+ np_local3 = &np_local2[5];
+
+ double np_local4[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ non_const_handle(np_local4[2]);
+ double np_local5[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ non_const_handle(&np_local5[2]);
+
+ // Constant handles are ok
+ double p_local1[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double [10]' can be declared 'const'
+ const double *p_local2 = &p_local1[2]; // Could be `const double *const`, but warning deactivated by default
+
+ double p_local3[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'double [10]' can be declared 'const'
+ const double &const_ref = p_local3[2];
+
+ double p_local4[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local4' of type 'double [10]' can be declared 'const'
+ const double *const_ptr;
+ const_ptr = &p_local4[2];
+
+ double p_local5[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local5' of type 'double [10]' can be declared 'const'
+ const_handle(p_local5[2]);
+ double p_local6[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local6' of type 'double [10]' can be declared 'const'
+ const_handle(&p_local6[2]);
+}
+
+void range_for() {
+ int np_local0[2] = {1, 2};
+ for (int &non_const_ref : np_local0) {
+ non_const_ref = 42;
+ }
+
+ int np_local1[2] = {1, 2};
+ for (auto &non_const_ref : np_local1) {
+ non_const_ref = 43;
+ }
+
+ int np_local2[2] = {1, 2};
+ for (auto &&non_const_ref : np_local2) {
+ non_const_ref = 44;
+ }
+
+ // FIXME the warning message is suboptimal. It could be defined as
+ // `int *const np_local3[2]` because the pointers are not reseated.
+ // But this is not easily deducable from the warning.
+ int *np_local3[2] = {&np_local0[0], &np_local0[1]};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'np_local3' of type 'int *[2]' can be declared 'const'
+ for (int *non_const_ptr : np_local3) {
+ *non_const_ptr = 45;
+ }
+
+ // FIXME same as above, but silenced
+ int *const np_local4[2] = {&np_local0[0], &np_local0[1]};
+ for (auto *non_const_ptr : np_local4) {
+ *non_const_ptr = 46;
+ }
+
+ int p_local0[2] = {1, 2};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int [2]' can be declared 'const'
+ for (int value : p_local0) {
+ // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'value' of type 'int' can be declared 'const'
+ }
+
+ int p_local1[2] = {1, 2};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int [2]' can be declared 'const'
+ for (const int &const_ref : p_local1) {
+ }
+
+ int *p_local2[2] = {&np_local0[0], &np_local0[1]};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'int *[2]' can be declared 'const'
+ for (const int *con_ptr : p_local2) {
+ }
+
+ int *p_local3[2] = {nullptr, nullptr};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'int *[2]' can be declared 'const'
+ for (const auto *con_ptr : p_local3) {
+ }
+}
+
+inline void *operator new(decltype(sizeof(void *)), void *p) { return p; }
+
+struct Value {
+};
+void placement_new() {
+ Value Mem;
+ Value *V = new (&Mem) Value;
+}
+
+struct ModifyingConversion {
+ operator int() { return 15; }
+};
+struct NonModifyingConversion {
+ operator int() const { return 15; }
+};
+void conversion_operators() {
+ ModifyingConversion np_local0;
+ NonModifyingConversion p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'NonModifyingConversion' can be declared 'const'
+
+ int np_local1 = np_local0;
+ np_local1 = p_local0;
+}
+
+void casts() {
+ decltype(sizeof(void *)) p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'decltype(sizeof(void *))' (aka 'unsigned long') can be declared 'const'
+ auto np_local0 = reinterpret_cast<void *>(p_local0);
+ np_local0 = nullptr;
+
+ int p_local1 = 43;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ short p_local2 = static_cast<short>(p_local1);
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'short' can be declared 'const'
+
+ int np_local1 = p_local2;
+ int &np_local2 = static_cast<int &>(np_local1);
+ np_local2 = 5;
+}
+
+void ternary_operator() {
+ int np_local0 = 1, np_local1 = 2;
+ int &np_local2 = true ? np_local0 : np_local1;
+ np_local2 = 2;
+
+ int p_local0 = 3, np_local3 = 5;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ const int &np_local4 = true ? p_local0 : ++np_local3;
+
+ int np_local5[3] = {1, 2, 3};
+ int &np_local6 = np_local5[1] < np_local5[2] ? np_local5[0] : np_local5[2];
+ np_local6 = 42;
+
+ int np_local7[3] = {1, 2, 3};
+ int *np_local8 = np_local7[1] < np_local7[2] ? &np_local7[0] : &np_local7[2];
+ *np_local8 = 42;
+}
+
+// taken from http://www.cplusplus.com/reference/type_traits/integral_constant/
+template <typename T, T v>
+struct integral_constant {
+ static constexpr T value = v;
+ using value_type = T;
+ using type = integral_constant<T, v>;
+ constexpr operator T() { return v; }
+};
+
+template <typename T>
+struct is_integral : integral_constant<bool, false> {};
+template <>
+struct is_integral<int> : integral_constant<bool, true> {};
+
+template <typename T>
+struct not_integral : integral_constant<bool, false> {};
+template <>
+struct not_integral<double> : integral_constant<bool, true> {};
+
+// taken from http://www.cplusplus.com/reference/type_traits/enable_if/
+template <bool Cond, typename T = void>
+struct enable_if {};
+
+template <typename T>
+struct enable_if<true, T> { using type = T; };
+
+template <typename T>
+struct TMPClass {
+ T alwaysConst() const { return T{}; }
+
+ template <typename T2 = T, typename = typename enable_if<is_integral<T2>::value>::type>
+ T sometimesConst() const { return T{}; }
+
+ template <typename T2 = T, typename = typename enable_if<not_integral<T2>::value>::type>
+ T sometimesConst() { return T{}; }
+};
+
+void meta_type() {
+ TMPClass<int> p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'TMPClass<int>' can be declared 'const'
+ p_local0.alwaysConst();
+ p_local0.sometimesConst();
+
+ TMPClass<double> p_local1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'TMPClass<double>' can be declared 'const'
+ p_local1.alwaysConst();
+
+ TMPClass<double> np_local0;
+ np_local0.alwaysConst();
+ np_local0.sometimesConst();
+}
+
+// This test is the essence from llvm/lib/Support/MemoryBuffer.cpp at line 450
+template <typename T>
+struct to_construct : T {
+ to_construct(int &j) {}
+};
+template <typename T>
+void placement_new_in_unique_ptr() {
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ int np_local0 = p_local0;
+ new to_construct<T>(np_local0);
+}
+
+struct stream_obj {};
+stream_obj &operator>>(stream_obj &o, unsigned &foo);
+void input_operator() {
+ stream_obj np_local0;
+ unsigned np_local1 = 42;
+ np_local0 >> np_local1;
+}
+
+struct stream_obj_template {};
+template <typename IStream>
+IStream &operator>>(IStream &o, unsigned &foo);
+
+template <typename Stream>
+void input_operator_template() {
+ Stream np_local0;
+ unsigned np_local1 = 42;
+ np_local0 >> np_local1;
+}
+
+// Test bit fields
+struct HardwareRegister {
+ unsigned field : 5;
+ unsigned : 7;
+ unsigned another : 20;
+};
+
+void TestRegisters() {
+ HardwareRegister np_reg0;
+ np_reg0.field = 3;
+
+ HardwareRegister p_reg1{3, 22};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_reg1' of type 'HardwareRegister' can be declared 'const'
+ const unsigned p_val = p_reg1.another;
+}
+
+struct IntWrapper {
+ IntWrapper &operator=(unsigned value) { return *this; }
+ template <typename Istream>
+ friend Istream &operator>>(Istream &is, IntWrapper &rhs);
+};
+struct IntMaker {
+ friend IntMaker &operator>>(IntMaker &, unsigned &);
+};
+template <typename Istream>
+Istream &operator>>(Istream &is, IntWrapper &rhs) {
+ unsigned np_local0 = 0;
+ is >> np_local0;
+ return is;
+}
+
+struct Actuator {
+ int actuations;
+};
+struct Sensor {
+ int observations;
+};
+struct System : public Actuator, public Sensor {
+};
+int some_computation(int arg);
+int test_inheritance() {
+ System np_sys;
+ np_sys.actuations = 5;
+ return some_computation(np_sys.actuations);
+}
+struct AnotherActuator : Actuator {
+};
+Actuator &test_return_polymorphic() {
+ static AnotherActuator np_local0;
+ return np_local0;
+}
+
+using f_signature = int *(*)(int &);
+int *my_alloc(int &size) { return new int[size]; }
+struct A {
+ int f(int &i) { return i + 1; }
+ int (A::*x)(int &);
+};
+void f() {
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ int np_local0 = 42;
+ f_signature action = my_alloc;
+ action(np_local0);
+ my_alloc(np_local0);
+
+ int np_local1 = 42;
+ A a;
+ a.x = &A::f;
+ (a.*(a.x))(np_local1);
+}
+
+struct nested_data {
+ int more_data;
+};
+struct repro_assignment_to_reference {
+ int my_data;
+ nested_data nested;
+};
+void assignment_reference() {
+ repro_assignment_to_reference np_local0{42};
+ int &np_local1 = np_local0.my_data;
+ np_local1++;
+
+ repro_assignment_to_reference np_local2;
+ int &np_local3 = np_local2.nested.more_data;
+ np_local3++;
+}
+
+struct non_const_iterator {
+ int data[42];
+
+ int *begin() { return &data[0]; }
+ int *end() { return &data[41]; }
+};
+
+// The problem is, that 'begin()' and 'end()' are not const overloaded, so
+// they are always a mutation. If 'np_local1' is fixed to const it results in
+// a compilation error.
+void for_bad_iterators() {
+ non_const_iterator np_local0;
+ non_const_iterator &np_local1 = np_local0;
+
+ for (int np_local2 : np_local1) {
+ np_local2++;
+ }
+
+ non_const_iterator np_local3;
+ for (int p_local0 : np_local3)
+ // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ ;
+
+ // Horrible code constructs...
+ {
+ non_const_iterator np_local4;
+ np_local4.data[0]++;
+ non_const_iterator np_local5;
+ for (int p_local1 : np_local4, np_local5)
+ // CHECK-MESSAGES: [[@LINE-1]]:10: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ ;
+
+ non_const_iterator np_local6;
+ non_const_iterator np_local7;
+ for (int p_local2 : 1 > 2 ? np_local6 : np_local7)
+ // CHECK-MESSAGES: [[@LINE-1]]:10: warning: variable 'p_local2' of type 'int' can be declared 'const'
+ ;
+
+ non_const_iterator np_local8;
+ non_const_iterator np_local9;
+ for (int p_local3 : 2 > 1 ? np_local8 : (np_local8, np_local9))
+ // CHECK-MESSAGES: [[@LINE-1]]:10: warning: variable 'p_local3' of type 'int' can be declared 'const'
+ ;
+ }
+}
+
+struct good_iterator {
+ int data[3] = {1, 2, 3};
+
+ int *begin() { return &data[0]; }
+ int *end() { return &data[2]; }
+ const int *begin() const { return &data[0]; }
+ const int *end() const { return &data[2]; }
+};
+
+void good_iterators() {
+ good_iterator p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'good_iterator' can be declared 'const'
+ good_iterator &p_local1 = p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'good_iterator &' can be declared 'const'
+
+ for (int p_local2 : p_local1) {
+ // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'p_local2' of type 'int' can be declared 'const'
+ (void)p_local2;
+ }
+
+ good_iterator p_local3;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'good_iterator' can be declared 'const'
+ for (int p_local4 : p_local3)
+ // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'p_local4' of type 'int' can be declared 'const'
+ ;
+ good_iterator np_local1;
+ for (int &np_local2 : np_local1)
+ np_local2++;
+}
+
+void for_bad_iterators_array() {
+ int np_local0[42];
+ int(&np_local1)[42] = np_local0;
+
+ for (int &np_local2 : np_local1) {
+ np_local2++;
+ }
+}
+void for_ok_iterators_array() {
+ int np_local0[42];
+ int(&p_local0)[42] = np_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int (&)[42]' can be declared 'const'
+
+ for (int p_local1 : p_local0) {
+ // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ (void)p_local1;
+ }
+}
+
+void take_ref(int &);
+void ternary_reference() {
+ int np_local0 = 42;
+ int np_local1 = 43;
+ take_ref((np_local0 > np_local1 ? np_local0 : (np_local0, np_local1)));
+}
+
+void complex_usage() {
+ int np_local0 = 42;
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ int np_local1 = 42;
+ (np_local0 == p_local0 ? np_local0 : (p_local0, np_local1))++;
+}
+
+template <typename T>
+struct SmallVectorBase {
+ T data[4];
+ void push_back(const T &el) {}
+ int size() const { return 4; }
+ T *begin() { return data; }
+ const T *begin() const { return data; }
+ T *end() { return data + 4; }
+ const T *end() const { return data + 4; }
+};
+
+template <typename T>
+struct SmallVector : SmallVectorBase<T> {};
+
+template <class T>
+void EmitProtocolMethodList(T &&Methods) {
+ // Note: If the template is uninstantiated the analysis does not figure out,
+ // that p_local0 could be const. Not sure why, but probably bails because
+ // some expressions are type-dependent.
+ SmallVector<const int *> p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'SmallVector<const int *>' can be declared 'const'
+ SmallVector<const int *> np_local0;
+ for (const auto *I : Methods) {
+ if (I == nullptr)
+ np_local0.push_back(I);
+ }
+ p_local0.size();
+}
+void instantiate() {
+ int *p_local0[4] = {nullptr, nullptr, nullptr, nullptr};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int *[4]' can be declared 'const'
+ EmitProtocolMethodList(p_local0);
+}
+struct base {
+ int member;
+};
+struct derived : base {};
+struct another_struct {
+ derived member;
+};
+void another_struct_f() {
+ another_struct np_local0{};
+ base &np_local1 = np_local0.member;
+ np_local1.member++;
+}
+struct list_init {
+ int &member;
+};
+void create_false_positive() {
+ int np_local0 = 42;
+ list_init p_local0 = {np_local0};
+ // CHECK-MESSAGES:[[@LINE-1]]:3: warning: variable 'p_local0' of type 'list_init' can be declared 'const'
+}
+struct list_init_derived {
+ base &member;
+};
+void list_init_derived_func() {
+ derived np_local0;
+ list_init_derived p_local0 = {np_local0};
+ // CHECK-MESSAGES:[[@LINE-1]]:3: warning: variable 'p_local0' of type 'list_init_derived' can be declared 'const'
+}
+template <typename L, typename R>
+struct ref_pair {
+ L &first;
+ R &second;
+};
+template <typename T>
+void list_init_template() {
+ T np_local0{};
+ ref_pair<T, T> p_local0 = {np_local0, np_local0};
+}
+void cast_in_class_hierarchy() {
+ derived np_local0;
+ base p_local1 = static_cast<base &>(np_local0);
+ // CHECK-MESSAGES:[[@LINE-1]]:3: warning: variable 'p_local1' of type 'base' can be declared 'const'
+}
+
+void function_ref_target(int);
+using my_function_type = void (&)(int);
+void func_references() {
+ // Could be const, because the reference is not adjusted but adding that
+ // has no effect and creates a compiler warning.
+ my_function_type ptr = function_ref_target;
+}
+
+#if 0
+template <typename T>
+T &return_ref() {
+ static T global;
+ return global;
+}
+template <typename T>
+T *return_ptr() { return &return_ref<T>(); }
+
+template <typename T>
+void auto_usage_variants() {
+ // FIXME: Currently all 'auto's that deduce to a reference are not ignored
+ // for the analysis. That results in bad transformations.
+ auto auto_val0 = T{};
+ auto &auto_val1 = auto_val0; // Bad
+ auto *auto_val2 = &auto_val0;
+
+ auto auto_ref0 = return_ref<T>(); // Bad
+ auto &auto_ref1 = return_ref<T>(); // Bad
+ auto *auto_ref2 = return_ptr<T>();
+
+ auto auto_ptr0 = return_ptr<T>();
+ auto &auto_ptr1 = auto_ptr0;
+ auto *auto_ptr2 = return_ptr<T>();
+
+ using MyTypedef = T;
+ auto auto_td0 = MyTypedef{};
+ auto &auto_td1 = auto_td0; // Bad
+ auto *auto_td2 = &auto_td0;
+}
+void instantiate_auto_cases() {
+ auto_usage_variants<int>();
+ auto_usage_variants<System>();
+}
+#endif
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-values.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-values.cpp
@@ -0,0 +1,168 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-const-correctness %t -- \
+// RUN: -config="{CheckOptions: [\
+// RUN: {key: 'cppcoreguidelines-const-correctness.TransformValues', value: 1},\
+// RUN: {key: 'cppcoreguidelines-const-correctness.WarnPointersAsValues', value: 0}, \
+// RUN: {key: 'cppcoreguidelines-const-correctness.TransformPointersAsValues', value: 0}, \
+// RUN: ]}" --
+
+bool global;
+char np_global = 0; // globals can't be known to be const
+
+namespace foo {
+int scoped;
+float np_scoped = 1; // namespace variables are like globals
+} // namespace foo
+
+// Lambdas should be ignored, because they do not follow the normal variable
+// semantic (e.g. the type is only known to the compiler).
+void lambdas() {
+ auto Lambda = [](int i) { return i < 0; };
+}
+
+void some_function(double, wchar_t);
+
+void some_function(double np_arg0, wchar_t np_arg1) {
+ int p_local0 = 2;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+ // CHECK-FIXES: const
+}
+
+void nested_scopes() {
+ {
+ int p_local1 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:5: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ // CHECK-FIXES: const
+ }
+}
+
+template <typename T>
+void define_locals(T np_arg0, T &np_arg1, int np_arg2) {
+ T np_local0 = 0;
+ int p_local1 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'int' can be declared 'const'
+ // CHECK-FIXES: const
+}
+
+void template_instantiation() {
+ const int np_local0 = 42;
+ int np_local1 = 42;
+
+ define_locals(np_local0, np_local1, np_local0);
+ define_locals(np_local1, np_local1, np_local1);
+}
+
+struct ConstNonConstClass {
+ ConstNonConstClass();
+ ConstNonConstClass(double &np_local0);
+ double nonConstMethod() {}
+ double constMethod() const {}
+ double modifyingMethod(double &np_arg0) const;
+
+ double NonConstMember;
+ const double ConstMember;
+
+ double &NonConstMemberRef;
+ const double &ConstMemberRef;
+
+ double *NonConstMemberPtr;
+ const double *ConstMemberPtr;
+};
+
+void direct_class_access() {
+ ConstNonConstClass p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'ConstNonConstClass' can be declared 'const'
+ // CHECK-FIXES: const
+ p_local0.constMethod();
+}
+
+void class_access_array() {
+ ConstNonConstClass p_local0[2];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'ConstNonConstClass [2]' can be declared 'const'
+ // CHECK-FIXES: const
+ p_local0[0].constMethod();
+}
+
+struct MyVector {
+ double *begin();
+ const double *begin() const;
+
+ double *end();
+ const double *end() const;
+
+ double &operator[](int index);
+ double operator[](int index) const;
+
+ double values[100];
+};
+
+void vector_usage() {
+ double p_local0[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double [10]' can be declared 'const'
+ // CHECK-FIXES: const
+}
+
+void range_for() {
+ int np_local0[2] = {1, 2};
+ int *np_local3[2] = {&np_local0[0], &np_local0[1]};
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'np_local3' of type 'int *[2]' can be declared 'const'
+ // CHECK-FIXES: const
+ for (int *non_const_ptr : np_local3) {
+ *non_const_ptr = 45;
+ }
+}
+
+void casts() {
+ decltype(sizeof(void *)) p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'decltype(sizeof(void *))' (aka 'unsigned long') can be declared 'const'
+ // CHECK-FIXES: const
+}
+
+// taken from http://www.cplusplus.com/reference/type_traits/integral_constant/
+template <typename T, T v>
+struct integral_constant {
+ static constexpr T value = v;
+ using value_type = T;
+ using type = integral_constant<T, v>;
+ constexpr operator T() { return v; }
+};
+
+template <typename T>
+struct is_integral : integral_constant<bool, false> {};
+template <>
+struct is_integral<int> : integral_constant<bool, true> {};
+
+template <typename T>
+struct not_integral : integral_constant<bool, false> {};
+template <>
+struct not_integral<double> : integral_constant<bool, true> {};
+
+// taken from http://www.cplusplus.com/reference/type_traits/enable_if/
+template <bool Cond, typename T = void>
+struct enable_if {};
+
+template <typename T>
+struct enable_if<true, T> { using type = T; };
+
+template <typename T>
+struct TMPClass {
+ T alwaysConst() const { return T{}; }
+
+ template <typename T2 = T, typename = typename enable_if<is_integral<T2>::value>::type>
+ T sometimesConst() const { return T{}; }
+
+ template <typename T2 = T, typename = typename enable_if<not_integral<T2>::value>::type>
+ T sometimesConst() { return T{}; }
+};
+
+void meta_type() {
+ TMPClass<int> p_local0;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'TMPClass<int>' can be declared 'const'
+ // CHECK-FIXES: const
+ p_local0.alwaysConst();
+ p_local0.sometimesConst();
+
+ TMPClass<double> p_local1;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'TMPClass<double>' can be declared 'const'
+ // CHECK-FIXES: const
+ p_local1.alwaysConst();
+}
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-pointer-as-values.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-transform-pointer-as-values.cpp
@@ -0,0 +1,13 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-const-correctness %t \
+// RUN: -config='{CheckOptions: \
+// RUN: [{key: "cppcoreguidelines-const-correctness.AnalyzeValues", value: 1},\
+// RUN: {key: "cppcoreguidelines-const-correctness.WarnPointersAsValues", value: 1}, \
+// RUN: {key: "cppcoreguidelines-const-correctness.TransformPointersAsValues", value: 1},\
+// RUN: ]}' --
+
+void potential_const_pointer() {
+ double np_local0[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ double *p_local0 = &np_local0[1];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double *' can be declared 'const'
+ // CHECK-FIXES: const
+}
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-pointer-as-values.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-pointer-as-values.cpp
@@ -0,0 +1,11 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-const-correctness %t \
+// RUN: -config='{CheckOptions: \
+// RUN: [{key: "cppcoreguidelines-const-correctness.AnalyzeValues", value: 1},\
+// RUN: {key: "cppcoreguidelines-const-correctness.WarnPointersAsValues", value: 1}]}' \
+// RUN: --
+
+void potential_const_pointer() {
+ double np_local0[10] = {0., 1., 2., 3., 4., 5., 6., 7., 8., 9.};
+ double *p_local0 = &np_local0[1];
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double *' can be declared 'const'
+}
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-cxx17.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-const-correctness-cxx17.cpp
@@ -0,0 +1,49 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-const-correctness %t -- -- -std=c++17
+
+template <typename L, typename R>
+struct MyPair {
+ L left;
+ R right;
+ MyPair(const L &ll, const R &rr) : left{ll}, right{rr} {}
+};
+
+void f() {
+ // FIXME: Decomposition Decls need special treatment, because they require to use 'auto'
+ // and the 'const' should only be added if all elements can be const.
+ // The issue is similar to multiple declarations in one statement.
+ // Simply bail for now.
+ auto [np_local0, np_local1] = MyPair<int, int>(42, 42);
+ np_local0++;
+ np_local1++;
+
+ auto [np_local2, p_local0] = MyPair<double, double>(42., 42.);
+ np_local2++;
+
+ auto [p_local1, np_local3] = MyPair<double, double>(42., 42.);
+ np_local3++;
+
+ auto [p_local2, p_local3] = MyPair<double, double>(42., 42.);
+}
+
+void g() {
+ int p_local0 = 42;
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int' can be declared 'const'
+}
+
+template <typename SomeValue>
+struct DoGooder {
+ DoGooder(void *accessor, SomeValue value) {
+ }
+};
+struct Bingus {
+ static constexpr auto someRandomConstant = 99;
+};
+template <typename Foo>
+struct HardWorker {
+ HardWorker() {
+ const DoGooder<int> anInstanceOf(nullptr, Foo::someRandomConstant);
+ }
+};
+struct TheContainer {
+ HardWorker<Bingus> m_theOtherInstance;
+};
Index: clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-const-correctness.rst
===================================================================
--- /dev/null
+++ clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-const-correctness.rst
@@ -0,0 +1,68 @@
+.. title:: clang-tidy - cppcoreguidelines-const-correctness
+
+cppcoreguidelines-const-correctness
+===================================
+
+This check implements detection of local variables which could be declared as
+``const``, but are not. Declaring variables as ``const`` is required by many
+coding guidelines, such as:
+`CppCoreGuidelines ES.25 <https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es25-declare-an-object-const-or-constexpr-unless-you-want-to-modify-its-value-later-on>`_
+and `High Integrity C++ 7.1.2 <http://www.codingstandard.com/rule/7-1-2-use-const-whenever-possible/>`_.
+
+Please note that this analysis is type-based only. Variables that are not modified
+but non-const handles might escape out of the scope are not diagnosed as potential
+``const``.
+
+.. code-block:: c++
+
+ // Declare a variable, which is not ``const`` ...
+ int i = 42;
+ // but use it as read-only. This means that `i` can be declared ``const``.
+ int result = i * i;
+
+The check analyzes values, pointers and references (if configured that way).
+For better understanding some code samples:
+
+.. code-block:: c++
+
+ // Normal values like built-ins or objects.
+ int potential_const_int = 42;
+ int copy_of_value = potential_const_int;
+
+ MyClass could_be_const;
+ could_be_const.const_qualified_method();
+
+ // References can be declared const as well.
+ int &reference_value = potential_const_int;
+ int another_copy = reference_value;
+
+ // Similar behaviour for pointers.
+ int *pointer_variable = &potential_const_int;
+ int last_copy = *pointer_variable;
+
+
+Options
+-------
+
+.. option:: AnalyzeValues (default = 1)
+
+ Enable or disable the analysis of ordinary value variables, like ``int i = 42;``
+
+.. option:: AnalyzeReferences (default = 1)
+
+ Enable or disable the analysis of reference variables, like ``int &ref = i;``
+
+.. option:: WarnPointersAsValues (default = 0)
+
+ This option enables the suggestion for ``const`` of the pointer itself.
+ Pointer values have two possibilities to be ``const``, the pointer itself
+ and the value pointing to.
+
+ .. code-block:: c++
+
+ const int value = 42;
+ const int * const pointer_variable = &value;
+
+ // The following operations are forbidden for `pointer_variable`.
+ // *pointer_variable = 44;
+ // pointer_variable = nullptr;
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -100,6 +100,14 @@
Finds condition variables in nested ``if`` statements that were also checked
in the outer ``if`` statement and were not changed.
+- New :doc:`cppcoreguidelines-const-correctness
+ <clang-tidy/checks/cppcoreguidelines-const-correctness>` check.
+
+ Suggest adding ``const`` to unmodified local variables.
+
+New check aliases
+^^^^^^^^^^^^^^^^^
+
Changes in existing checks
^^^^^^^^^^^^^^^^^^^^^^^^^^
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -16,6 +16,7 @@
#include "../readability/MagicNumbersCheck.h"
#include "AvoidGotoCheck.h"
#include "AvoidNonConstGlobalVariablesCheck.h"
+#include "ConstCorrectnessCheck.h"
#include "InitVariablesCheck.h"
#include "InterfacesGlobalInitCheck.h"
#include "MacroUsageCheck.h"
@@ -52,6 +53,8 @@
"cppcoreguidelines-avoid-magic-numbers");
CheckFactories.registerCheck<AvoidNonConstGlobalVariablesCheck>(
"cppcoreguidelines-avoid-non-const-global-variables");
+ CheckFactories.registerCheck<ConstCorrectnessCheck>(
+ "cppcoreguidelines-const-correctness");
CheckFactories.registerCheck<modernize::UseOverrideCheck>(
"cppcoreguidelines-explicit-virtual-functions");
CheckFactories.registerCheck<InitVariablesCheck>(
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.h
@@ -0,0 +1,59 @@
+//===--- ConstCorrectnessCheck.h - clang-tidy -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
+
+namespace clang {
+namespace tidy {
+
+namespace cppcoreguidelines {
+
+/// This check warns on variables which could be declared const but are not.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-const.html
+class ConstCorrectnessCheck : public ClangTidyCheck {
+public:
+ ConstCorrectnessCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ AnalyzeValues(Options.get("AnalyzeValues", 1)),
+ AnalyzeReferences(Options.get("AnalyzeReferences", 1)),
+ WarnPointersAsValues(Options.get("WarnPointersAsValues", 0)),
+ TransformValues(Options.get("TransformValues", 1)),
+ TransformReferences(Options.get("TransformReferences", 1)),
+ TransformPointersAsValues(Options.get("TransformPointersAsValues", 0)) {
+ }
+
+ void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ void registerScope(const CompoundStmt *LocalScope, ASTContext *Context);
+
+ using MutationAnalyzer = std::unique_ptr<ExprMutationAnalyzer>;
+ llvm::DenseMap<const CompoundStmt *, MutationAnalyzer> ScopesCache;
+
+ const bool AnalyzeValues;
+ const bool AnalyzeReferences;
+ const bool WarnPointersAsValues;
+
+ const bool TransformValues;
+ const bool TransformReferences;
+ const bool TransformPointersAsValues;
+};
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp
@@ -0,0 +1,178 @@
+//===--- ConstCorrectnessCheck.cpp - clang-tidy -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ConstCorrectnessCheck.h"
+#include "../utils/FixItHintUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+namespace {
+// FIXME: This matcher exists in some other code-review as well.
+// It should probably move to ASTMatchers.
+AST_MATCHER(VarDecl, isLocal) { return Node.isLocalVarDecl(); }
+AST_MATCHER_P(DeclStmt, containsDeclaration2,
+ ast_matchers::internal::Matcher<Decl>, InnerMatcher) {
+ return ast_matchers::internal::matchesFirstInPointerRange(
+ InnerMatcher, Node.decl_begin(), Node.decl_end(), Finder, Builder);
+}
+AST_MATCHER(ReferenceType, isSpelledAsLValue) {
+ return Node.isSpelledAsLValue();
+}
+AST_MATCHER(Type, isDependentType) { return Node.isDependentType(); }
+} // namespace
+
+void ConstCorrectnessCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "AnalyzeValues", AnalyzeValues);
+ Options.store(Opts, "AnalyzeReferences", AnalyzeReferences);
+ Options.store(Opts, "WarnPointersAsValues", WarnPointersAsValues);
+
+ Options.store(Opts, "TransformValues", TransformValues);
+ Options.store(Opts, "TransformReferences", TransformReferences);
+ Options.store(Opts, "TransformPointersAsValues", TransformPointersAsValues);
+}
+
+void ConstCorrectnessCheck::registerMatchers(MatchFinder *Finder) {
+ const auto ConstType = hasType(isConstQualified());
+ const auto ConstReference = hasType(references(isConstQualified()));
+ const auto RValueReference = hasType(
+ referenceType(anyOf(rValueReferenceType(), unless(isSpelledAsLValue()))));
+
+ const auto TemplateType = anyOf(
+ hasType(hasCanonicalType(templateTypeParmType())),
+ hasType(substTemplateTypeParmType()), hasType(isDependentType()),
+ // References to template types, their substitutions or typedefs to
+ // template types need to be considered as well.
+ hasType(referenceType(pointee(hasCanonicalType(templateTypeParmType())))),
+ hasType(referenceType(pointee(substTemplateTypeParmType()))));
+
+ const auto AutoTemplateType = varDecl(
+ anyOf(hasType(autoType()), hasType(referenceType(pointee(autoType()))),
+ hasType(pointerType(pointee(autoType())))),
+ hasInitializer(isInstantiationDependent()));
+
+ const auto FunctionPointerRef =
+ hasType(hasCanonicalType(referenceType(pointee(functionType()))));
+
+ // Match local variables which could be 'const' if not modified later.
+ // Example: `int i = 10` would match `int i`.
+ const auto LocalValDecl = varDecl(
+ allOf(isLocal(), hasInitializer(anything()),
+ unless(anyOf(ConstType, ConstReference, TemplateType,
+ AutoTemplateType, RValueReference, FunctionPointerRef,
+ hasType(cxxRecordDecl(isLambda())), isImplicit()))));
+
+ // Match the function scope for which the analysis of all local variables
+ // shall be run.
+ const auto FunctionScope = functionDecl(hasBody(
+ compoundStmt(findAll(declStmt(allOf(containsDeclaration2(
+ LocalValDecl.bind("local-value")),
+ unless(has(decompositionDecl()))))
+ .bind("decl-stmt")))
+ .bind("scope")));
+
+ Finder->addMatcher(FunctionScope, this);
+}
+
+/// Classify for a variable in what the Const-Check is interested.
+enum class VariableCategory { Value, Reference, Pointer };
+
+void ConstCorrectnessCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *LocalScope = Result.Nodes.getNodeAs<CompoundStmt>("scope");
+ assert(LocalScope && "Did not match scope for local variable");
+ registerScope(LocalScope, Result.Context);
+
+ const auto *Variable = Result.Nodes.getNodeAs<VarDecl>("local-value");
+ assert(Variable && "Did not match local variable definition");
+
+ VariableCategory VC = VariableCategory::Value;
+ if (Variable->getType()->isReferenceType())
+ VC = VariableCategory::Reference;
+ if (Variable->getType()->isPointerType())
+ VC = VariableCategory::Pointer;
+
+ // Each variable can only in one category: Value, Pointer, Reference.
+ // Analysis can be controlled for every category.
+ if (VC == VariableCategory::Reference && !AnalyzeReferences)
+ return;
+
+ if (VC == VariableCategory::Reference &&
+ Variable->getType()->getPointeeType()->isPointerType() &&
+ !WarnPointersAsValues)
+ return;
+
+ if (VC == VariableCategory::Pointer && !WarnPointersAsValues)
+ return;
+
+ if (VC == VariableCategory::Value && !AnalyzeValues)
+ return;
+
+ // Offload const-analysis to utility function.
+ if (ScopesCache[LocalScope]->isMutated(Variable))
+ return;
+
+ auto Diag = diag(Variable->getBeginLoc(),
+ "variable %0 of type %1 can be declared 'const'")
+ << Variable << Variable->getType();
+
+ const auto *VarDeclStmt = Result.Nodes.getNodeAs<DeclStmt>("decl-stmt");
+
+ // It can not be guaranteed that the variable is declared isolated, therefore
+ // a transformation might effect the other variables as well and be incorrect.
+ if (VarDeclStmt == nullptr || !VarDeclStmt->isSingleDecl())
+ return;
+
+ using namespace utils::fixit;
+ using llvm::Optional;
+ if (VC == VariableCategory::Value && TransformValues) {
+ if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+ *Variable, *Result.Context, DeclSpec::TQ_const,
+ QualifierTarget::Value, QualifierPolicy::Right)) {
+ Diag << *Fix;
+ // FIXME: Add '{}' for default initialization if no user-defined default
+ // constructor exists and there is no initializer.
+ }
+ return;
+ }
+
+ if (VC == VariableCategory::Reference && TransformReferences) {
+ if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+ *Variable, *Result.Context, DeclSpec::TQ_const,
+ QualifierTarget::Value, QualifierPolicy::Right))
+ Diag << *Fix;
+ return;
+ }
+
+ if (VC == VariableCategory::Pointer) {
+ if (WarnPointersAsValues && TransformPointersAsValues) {
+ if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+ *Variable, *Result.Context, DeclSpec::TQ_const,
+ QualifierTarget::Value, QualifierPolicy::Right))
+ Diag << *Fix;
+ }
+ return;
+ }
+}
+
+void ConstCorrectnessCheck::registerScope(const CompoundStmt *LocalScope,
+ ASTContext *Context) {
+ if (ScopesCache.find(LocalScope) == ScopesCache.end())
+ ScopesCache.insert(std::make_pair(
+ LocalScope,
+ std::make_unique<ExprMutationAnalyzer>(*LocalScope, *Context)));
+}
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -6,6 +6,7 @@
add_clang_library(clangTidyCppCoreGuidelinesModule
AvoidGotoCheck.cpp
AvoidNonConstGlobalVariablesCheck.cpp
+ ConstCorrectnessCheck.cpp
CppCoreGuidelinesTidyModule.cpp
InitVariablesCheck.cpp
InterfacesGlobalInitCheck.cpp
@@ -28,6 +29,12 @@
SpecialMemberFunctionsCheck.cpp
LINK_LIBS
+ clangAnalysis
+ clangAST
+ clangASTMatchers
+ clangBasic
+ clangLex
+ clangSerialization
clangTidy
clangTidyMiscModule
clangTidyModernizeModule
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