[Clang-tidy] check for malloc, realloc and free calls
Summary:
This checker flags the use of C-style memory management functionality and notes about modern alternatives.
In an earlier revision it tried to autofix some kind of patterns, but that was a bad idea. Since memory management can be so widespread in a program, manual updating is most likely necessary.
Maybe for special cases, there could be later additions to this basic checker.
This is the first checker I wrote and I never did something with clang (only compiling programs). So whenever I missed conventions or did plain retarded stuff, feel free to point it out! I am willing to fix them and write a better checker.
I hope the patch does work, I never did this either. On a testapply in my repository it did, but I am pretty unconfident in my patching skills :)
Reviewers: aaron.ballman, hokein, alexfh, malcolm.parsons
Subscribers: cfe-commits, JDevlieghere, nemanjai, Eugene.Zelenko, Prazek, mgorny, modocache
Tags: #clang-tools-extra
Differential Revision: https://reviews.llvm.org/D26167
Patch by Jonas Toth!
llvm-svn: 289546
GitOrigin-RevId: ebdfb9cf0cea0bd9ae91052b714397569d1c653a
diff --git a/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tidy/cppcoreguidelines/CMakeLists.txt
index 62d9a8a..43ac55d 100644
--- a/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -3,6 +3,7 @@
add_clang_library(clangTidyCppCoreGuidelinesModule
CppCoreGuidelinesTidyModule.cpp
InterfacesGlobalInitCheck.cpp
+ NoMallocCheck.cpp
ProBoundsArrayToPointerDecayCheck.cpp
ProBoundsConstantArrayIndexCheck.cpp
ProBoundsPointerArithmeticCheck.cpp
diff --git a/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index b34314c..6b9de8d 100644
--- a/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -12,6 +12,7 @@
#include "../ClangTidyModuleRegistry.h"
#include "../misc/UnconventionalAssignOperatorCheck.h"
#include "InterfacesGlobalInitCheck.h"
+#include "NoMallocCheck.h"
#include "ProBoundsArrayToPointerDecayCheck.h"
#include "ProBoundsConstantArrayIndexCheck.h"
#include "ProBoundsPointerArithmeticCheck.h"
@@ -35,6 +36,7 @@
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<InterfacesGlobalInitCheck>(
"cppcoreguidelines-interfaces-global-init");
+ CheckFactories.registerCheck<NoMallocCheck>("cppcoreguidelines-no-malloc");
CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
"cppcoreguidelines-pro-bounds-array-to-pointer-decay");
CheckFactories.registerCheck<ProBoundsConstantArrayIndexCheck>(
diff --git a/clang-tidy/cppcoreguidelines/NoMallocCheck.cpp b/clang-tidy/cppcoreguidelines/NoMallocCheck.cpp
new file mode 100644
index 0000000..d747fca
--- /dev/null
+++ b/clang-tidy/cppcoreguidelines/NoMallocCheck.cpp
@@ -0,0 +1,62 @@
+//===--- NoMallocCheck.cpp - clang-tidy------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "NoMallocCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include <iostream>
+#include <string>
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+void NoMallocCheck::registerMatchers(MatchFinder *Finder) {
+ // C-style memory management is only problematic in C++.
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ // Registering malloc, will suggest RAII.
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(hasAnyName("::malloc", "::calloc"))))
+ .bind("aquisition"),
+ this);
+
+ // Registering realloc calls, suggest std::vector or std::string.
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(hasName("::realloc")))).bind("realloc"),
+ this);
+
+ // Registering free calls, will suggest RAII instead.
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(hasName("::free")))).bind("free"), this);
+}
+
+void NoMallocCheck::check(const MatchFinder::MatchResult &Result) {
+ const CallExpr *Call = nullptr;
+ StringRef Recommendation;
+
+ if ((Call = Result.Nodes.getNodeAs<CallExpr>("aquisition")))
+ Recommendation = "consider a container or a smart pointer";
+ else if ((Call = Result.Nodes.getNodeAs<CallExpr>("realloc")))
+ Recommendation = "consider std::vector or std::string";
+ else if ((Call = Result.Nodes.getNodeAs<CallExpr>("free")))
+ Recommendation = "use RAII";
+
+ assert(Call && "Unhandled binding in the Matcher");
+
+ diag(Call->getLocStart(), "do not manage memory manually; %0")
+ << Recommendation << SourceRange(Call->getLocStart(), Call->getLocEnd());
+}
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tidy/cppcoreguidelines/NoMallocCheck.h b/clang-tidy/cppcoreguidelines/NoMallocCheck.h
new file mode 100644
index 0000000..cf2a8a2
--- /dev/null
+++ b/clang-tidy/cppcoreguidelines/NoMallocCheck.h
@@ -0,0 +1,44 @@
+//===--- NoMallocCheck.h - clang-tidy----------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_NO_MALLOC_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_NO_MALLOC_H
+
+#include "../ClangTidy.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+/// This checker is concerned with C-style memory management and suggest modern
+/// alternatives to it.
+/// The check is only enabled in C++. For analyzing malloc calls see Clang
+/// Static Analyzer - unix.Malloc.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-no-malloc.html
+class NoMallocCheck : public ClangTidyCheck {
+public:
+ NoMallocCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+
+ /// Registering for malloc, calloc, realloc and free calls.
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+
+ /// Checks matched function calls and gives suggestion to modernize the code.
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_NO_MALLOC_H
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index fa68339..1b8a916 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -81,6 +81,10 @@
Warns if an object is used after it has been moved, without an intervening
reinitialization.
+- New `cppcoreguidelines-no-malloc
+ <http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-no-malloc.html>`_ check
+ warns if C-style memory management is used and suggests the use of RAII.
+
- `modernize-make-unique
<http://clang.llvm.org/extra/clang-tidy/checks/modernize-make-unique.html>`_
and `modernize-make-shared
diff --git a/docs/clang-tidy/checks/cppcoreguidelines-no-malloc.rst b/docs/clang-tidy/checks/cppcoreguidelines-no-malloc.rst
new file mode 100644
index 0000000..508c680
--- /dev/null
+++ b/docs/clang-tidy/checks/cppcoreguidelines-no-malloc.rst
@@ -0,0 +1,27 @@
+.. title:: clang-tidy - cppcoreguidelines-no-malloc
+
+cppcoreguidelines-no-malloc
+===========================
+
+This check handles C-Style memory management using ``malloc()``, ``realloc()``,
+``calloc()`` and ``free()``. It warns about its use and tries to suggest the use
+of an appropriate RAII object.
+See `C++ Core Guidelines
+<https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rr-mallocfree>
+
+There is no attempt made to provide fixit hints, since manual resource management isn't
+easily transformed automatically into RAII.
+
+.. code-block:: c++
+
+ // Warns each of the following lines.
+ // Containers like std::vector or std::string should be used.
+ char* some_string = (char*) malloc(sizeof(char) * 20);
+ char* some_string = (char*) realloc(sizeof(char) * 30);
+ free(some_string);
+
+ int* int_array = (int*) calloc(30, sizeof(int));
+
+ // Rather use a smartpointer or stack variable.
+ struct some_struct* s = (struct some_struct*) malloc(sizeof(struct some_struct));
+
diff --git a/docs/clang-tidy/checks/list.rst b/docs/clang-tidy/checks/list.rst
index 7cbcafc..26db6fc 100644
--- a/docs/clang-tidy/checks/list.rst
+++ b/docs/clang-tidy/checks/list.rst
@@ -22,6 +22,7 @@
cert-msc50-cpp
cert-oop11-cpp (redirects to misc-move-constructor-init) <cert-oop11-cpp>
cppcoreguidelines-interfaces-global-init
+ cppcoreguidelines-no-malloc
cppcoreguidelines-pro-bounds-array-to-pointer-decay
cppcoreguidelines-pro-bounds-constant-array-index
cppcoreguidelines-pro-bounds-pointer-arithmetic
diff --git a/test/clang-tidy/cppcoreguidelines-no-malloc.cpp b/test/clang-tidy/cppcoreguidelines-no-malloc.cpp
new file mode 100644
index 0000000..8f84024
--- /dev/null
+++ b/test/clang-tidy/cppcoreguidelines-no-malloc.cpp
@@ -0,0 +1,42 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-no-malloc %t
+
+using size_t = unsigned long;
+
+void *malloc(size_t size);
+void *calloc(size_t num, size_t size);
+void *realloc(void *ptr, size_t size);
+void free(void *ptr);
+
+void malloced_array() {
+ int *array0 = (int *)malloc(sizeof(int) * 20);
+ // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not manage memory manually; consider a container or a smart pointer [cppcoreguidelines-no-malloc]
+
+ int *zeroed = (int *)calloc(20, sizeof(int));
+ // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not manage memory manually; consider a container or a smart pointer [cppcoreguidelines-no-malloc]
+
+ // reallocation memory, std::vector shall be used
+ char *realloced = (char *)realloc(array0, 50 * sizeof(int));
+ // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: do not manage memory manually; consider std::vector or std::string [cppcoreguidelines-no-malloc]
+
+ // freeing memory the bad way
+ free(realloced);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not manage memory manually; use RAII [cppcoreguidelines-no-malloc]
+
+ // check if a call to malloc as function argument is found as well
+ free(malloc(20));
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not manage memory manually; use RAII [cppcoreguidelines-no-malloc]
+ // CHECK-MESSAGES: :[[@LINE-2]]:8: warning: do not manage memory manually; consider a container or a smart pointer [cppcoreguidelines-no-malloc]
+}
+
+/// newing an array is still not good, but not relevant to this checker
+void newed_array() {
+ int *new_array = new int[10]; // OK(1)
+}
+
+void arbitrary_call() {
+ // we dont want every function to raise the warning even if malloc is in the name
+ malloced_array(); // OK(2)
+
+ // completly unrelated function call to malloc
+ newed_array(); // OK(3)
+}
