fiesh created this revision.
fiesh added a reviewer: aaron.ballman.
fiesh added a project: clang-tools-extra.
Herald added subscribers: cfe-commits, kbarton, nemanjai.
Herald added a project: clang.
fiesh requested review of this revision.
As system headers are in general out of reach, it makes no sense to warn on
pointer decays happening in them.
This is a reboot of https://reviews.llvm.org/D31130
It is essentially unchanged, only updated to the new repository as well as
minor API changes.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D88833
Files:
clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
clang-tools-extra/test/clang-tidy/checkers/Inputs/cppcoreguidelines-pro-bounds-array-to-pointer-decay/macro.h
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
@@ -1,4 +1,6 @@
-// RUN: %check_clang_tidy %s cppcoreguidelines-pro-bounds-array-to-pointer-decay %t
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-bounds-array-to-pointer-decay %t -- -- -isystem%S/Inputs/cppcoreguidelines-pro-bounds-array-to-pointer-decay
+
+#include <macro.h>
#include <stddef.h>
namespace gsl {
@@ -8,7 +10,7 @@
template <class U, size_t N>
array_view(U (&arr)[N]);
};
-}
+} // namespace gsl
void pointerfun(int *p);
void arrayfun(int p[]);
@@ -29,9 +31,9 @@
gsl::array_view<int> av(a);
arrayviewfun(av); // OK
- int i = a[0]; // OK
- int j = a[(1 + 2)];// OK
- pointerfun(&a[0]); // OK
+ int i = a[0]; // OK
+ int j = a[(1 + 2)]; // OK
+ pointerfun(&a[0]); // OK
for (auto &e : a) // OK, iteration internally decays array to pointer
e = 1;
@@ -41,11 +43,53 @@
return "clang"; // OK, decay string literal to pointer
}
const char *g2() {
- return ("clang"); // OK, ParenExpr hides the literal-pointer decay
+ return ("clang"); // OK, ParenExpr hides the literal-pointer decay
}
void f2(void *const *);
void bug25362() {
void *a[2];
- f2(static_cast<void *const*>(a)); // OK, explicit cast
+ f2(static_cast<void *const *>(a)); // OK, explicit cast
+}
+
+void user_fn_decay_str(const char *);
+void user_fn_decay_int_array(const int *);
+void bug32239() {
+ sys_macro_with_pretty_function_string_decay; // Ok
+ sys_macro_with_sys_string_decay; // Ok
+ sys_macro_with_sys_int_array_decay; // Ok
+
+ sys_fn_decay_str(__PRETTY_FUNCTION__); // Ok
+
+ sys_fn_decay_str(SYS_STRING); // Not Ok - should it be ok?
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ sys_fn_decay_int_array(SYS_INT_ARRAY); // Not Ok
+ // CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ user_code_in_sys_macro(sys_fn_decay_str(__PRETTY_FUNCTION__)); // Ok
+
+ user_code_in_sys_macro(sys_fn_decay_str(SYS_STRING)); // Not Ok - should it be ok?
+ // CHECK-MESSAGES: :[[@LINE-1]]:43: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ user_code_in_sys_macro(sys_fn_decay_int_array(SYS_INT_ARRAY)); // Not Ok
+ // CHECK-MESSAGES: :[[@LINE-1]]:49: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ const char UserString[1] = "";
+ decay_to_char_pointer_in_macro(UserString); // Not Ok
+ // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ decay_to_char_pointer_in_macro(__PRETTY_FUNCTION__); // Ok
+
+ int a[5];
+ decay_to_int_pointer_in_macro(a); // Not Ok
+ // CHECK-MESSAGES: :[[@LINE-1]]:33: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ user_fn_decay_str(__PRETTY_FUNCTION__); // Ok
+
+ user_fn_decay_str(SYS_STRING); // Not Ok - should it be ok?
+ // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+
+ user_fn_decay_int_array(SYS_INT_ARRAY); // Not ok
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
}
Index: clang-tools-extra/test/clang-tidy/checkers/Inputs/cppcoreguidelines-pro-bounds-array-to-pointer-decay/macro.h
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/Inputs/cppcoreguidelines-pro-bounds-array-to-pointer-decay/macro.h
@@ -0,0 +1,14 @@
+const char SYS_STRING[2] = "s";
+const int SYS_INT_ARRAY[2] = {0, 0};
+
+void sys_fn_decay_str(const char *);
+void sys_fn_decay_int_array(const int *);
+
+#define sys_macro_with_pretty_function_string_decay sys_fn_decay_str(__PRETTY_FUNCTION__)
+#define sys_macro_with_sys_string_decay sys_fn_decay_str(SYS_STRING)
+#define sys_macro_with_sys_int_array_decay sys_fn_decay_int_array(SYS_INT_ARRAY)
+
+#define user_code_in_sys_macro(expr) expr;
+
+#define decay_to_char_pointer_in_macro(expr) sys_fn_decay_str(expr)
+#define decay_to_int_pointer_in_macro(expr) sys_fn_decay_int_array(expr)
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
@@ -46,29 +46,49 @@
return InnerMatcher.matches(*E, Finder, Builder);
}
+
+AST_MATCHER(ImplicitCastExpr, isArrayToPointerDecay) {
+ return Node.getCastKind() == CK_ArrayToPointerDecay;
+}
+
+AST_MATCHER(ImplicitCastExpr, sysSymbolDecayInSysHeader) {
+ auto &SM = Finder->getASTContext().getSourceManager();
+ if (!SM.isInSystemMacro(Node.getBeginLoc())) {
+ return false;
+ }
+
+ if (const auto *SymbolDeclRef = dyn_cast<DeclRefExpr>(Node.getSubExpr())) {
+ const ValueDecl *SymbolDecl = SymbolDeclRef->getDecl();
+ if (SymbolDecl && SM.isInSystemHeader(SymbolDecl->getLocation()))
+ return true;
+ }
+ return false;
+}
} // namespace
void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
- // The only allowed array to pointer decay
+ // We only allowed array to pointer decays
// 1) just before array subscription
// 2) inside a range-for over an array
// 3) if it converts a string literal to a pointer
+ // 4) if it is caused by a system macro
Finder->addMatcher(
- traverse(ast_type_traits::TK_AsIs,
- implicitCastExpr(
- unless(hasParent(arraySubscriptExpr())),
- unless(hasParentIgnoringImpCasts(explicitCastExpr())),
- unless(isInsideOfRangeBeginEndStmt()),
- unless(hasSourceExpression(ignoringParens(stringLiteral()))))
- .bind("cast")),
+ traverse(
+ ast_type_traits::TK_AsIs,
+ implicitCastExpr(
+ isArrayToPointerDecay(), unless(hasParent(arraySubscriptExpr())),
+ unless(hasParentIgnoringImpCasts(explicitCastExpr())),
+ unless(isInsideOfRangeBeginEndStmt()),
+ unless(hasSourceExpression(ignoringParens(stringLiteral()))),
+ unless(hasSourceExpression(ignoringParens(predefinedExpr()))),
+ unless(sysSymbolDecayInSysHeader()))
+ .bind("cast")),
this);
}
void ProBoundsArrayToPointerDecayCheck::check(
const MatchFinder::MatchResult &Result) {
const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
- if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)
- return;
diag(MatchedCast->getExprLoc(), "do not implicitly decay an array into a "
"pointer; consider using gsl::array_view or "
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