baloghadamsoftware created this revision.
Herald added a subscriber: rnkovacs.
The check now recognizes error cases like `new char[strlen(s + 1)]` and
suggests a fix in the format `new char[strlen(s) + 1]`.
https://reviews.llvm.org/D39367
Files:
clang-tidy/bugprone/MisplacedOperatorInStrlenInAllocCheck.cpp
docs/ReleaseNotes.rst
docs/clang-tidy/checks/bugprone-misplaced-operator-in-strlen-in-alloc.rst
test/clang-tidy/bugprone-misplaced-operator-in-strlen-in-alloc.cpp
Index: test/clang-tidy/bugprone-misplaced-operator-in-strlen-in-alloc.cpp
===================================================================
--- test/clang-tidy/bugprone-misplaced-operator-in-strlen-in-alloc.cpp
+++ test/clang-tidy/bugprone-misplaced-operator-in-strlen-in-alloc.cpp
@@ -29,3 +29,9 @@
char *new_name = (char*) std::malloc(non_std::strlen(name + 1));
// Ignore functions of the strlen family in custom namespaces
}
+
+void bad_new_strlen(char *name) {
+ char *new_name = new char[std::strlen(name + 1)];
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: Addition operator is applied to the argument of strlen
+ // CHECK-FIXES: {{^ char \*new_name = new char\[}}std::strlen(name) + 1{{\];$}}
+}
Index: docs/clang-tidy/checks/bugprone-misplaced-operator-in-strlen-in-alloc.rst
===================================================================
--- docs/clang-tidy/checks/bugprone-misplaced-operator-in-strlen-in-alloc.rst
+++ docs/clang-tidy/checks/bugprone-misplaced-operator-in-strlen-in-alloc.rst
@@ -7,11 +7,12 @@
``strnlen()``, ``strnlen_s()``, ``wcslen()``, ``wcsnlen()`` and ``wcsnlen_s()``
functions instead of to the result and use its return value as an argument of a
memory allocation function (``malloc()``, ``calloc()``, ``realloc()``,
-``alloca()``). Cases where ``1`` is added both to the parameter and the result
-of the ``strlen()``-like function are ignored, as are cases where the whole
-addition is surrounded by extra parentheses.
+``alloca()``) or the ``new[]`` operator in `C++`. Cases where ``1`` is added
+both to the parameter and the result of the ``strlen()``-like function are
+ignored, as are cases where the whole addition is surrounded by extra
+parentheses.
-Example code:
+`C` example code:
.. code-block:: c
@@ -28,6 +29,24 @@
char *c = (char*) malloc(strlen(str) + 1);
+`C++` example code:
+
+.. code-block:: c++
+
+ void bad_new(char *str) {
+ char *c = new char[strlen(str + 1)];
+ }
+
+
+As in the `C` code with the ``malloc()`` function, the suggested fix is to
+add ``1`` to the return value of ``strlen()`` and not to its argument. In the
+example above the fix would be
+
+.. code-block:: c++
+
+ char *c = new char[strlen(str) + 1];
+
+
Example for silencing the bug report:
.. code-block:: c
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -64,7 +64,7 @@
``strlen()``, ``strnlen()``, ``strnlen_s()``, ``wcslen()``, ``wcsnlen()`` and
``wcsnlen_s()`` functions instead of to the result and use its return value as
an argument of a memory allocation function (``malloc()``, ``calloc()``,
- ``realloc()``, ``alloca()``).
+ ``realloc()``, ``alloca()``) or the ``new[]`` operator in `C++`.
- Renamed checks to use correct term "implicit conversion" instead of "implicit
cast" and modified messages and option names accordingly:
Index: clang-tidy/bugprone/MisplacedOperatorInStrlenInAllocCheck.cpp
===================================================================
--- clang-tidy/bugprone/MisplacedOperatorInStrlenInAllocCheck.cpp
+++ clang-tidy/bugprone/MisplacedOperatorInStrlenInAllocCheck.cpp
@@ -48,26 +48,28 @@
const auto Alloc1Func =
functionDecl(anyOf(hasName("::calloc"), hasName("std::calloc"),
hasName("::realloc"), hasName("std::realloc")));
-
Finder->addMatcher(
callExpr(callee(Alloc0Func), hasArgument(0, BadArg)).bind("Alloc"), this);
Finder->addMatcher(
callExpr(callee(Alloc1Func), hasArgument(1, BadArg)).bind("Alloc"), this);
+ Finder->addMatcher(
+ cxxNewExpr(isArrayForm(), hasArraySize(BadArg)).bind("Alloc"), this);
}
void MisplacedOperatorInStrlenInAllocCheck::check(
const MatchFinder::MatchResult &Result) {
- const auto *Alloc = Result.Nodes.getNodeAs<CallExpr>("Alloc");
+ const Expr *Alloc = Result.Nodes.getNodeAs<CallExpr>("Alloc");
+ if (!Alloc) Alloc = Result.Nodes.getNodeAs<CXXNewExpr>("Alloc");
const auto *StrLen = Result.Nodes.getNodeAs<CallExpr>("StrLen");
const auto *BinOp = Result.Nodes.getNodeAs<BinaryOperator>("BinOp");
const StringRef StrLenText = Lexer::getSourceText(
CharSourceRange::getTokenRange(StrLen->getSourceRange()),
*Result.SourceManager, getLangOpts());
- const StringRef StrLenBegin = StrLenText.substr(0, StrLenText.find('(') + 1);
const StringRef Arg0Text = Lexer::getSourceText(
CharSourceRange::getTokenRange(StrLen->getArg(0)->getSourceRange()),
*Result.SourceManager, getLangOpts());
+ const StringRef StrLenBegin = StrLenText.substr(0, StrLenText.find(Arg0Text));
const StringRef StrLenEnd = StrLenText.substr(
StrLenText.find(Arg0Text) + Arg0Text.size(), StrLenText.size());
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