[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

1 files changed, 62 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/NoMallocCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/NoMallocCheck.cpp
new file mode 100644
index 00000000000..d747fca6c47
--- /dev/null
+++ b/clang-tools-extra/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