[clang] [analyzer] Remove redundant bug type DoubleDelete (PR #147542)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-static-analyzer-1

Author: Donát Nagy (NagyDonat)

<details>
<summary>Changes</summary>

This commit removes the DoubleDelete bug type from `MallocChecker.cpp` because it's completely redundant with the `DoubleFree` bug (which is already used for all allocator families, including new/delete).

This simplifies the code of the checker and prevents the potential confusion caused by two semantically equivalent and very similar, but not identical bug report messages.

---
Full diff: https://github.com/llvm/llvm-project/pull/147542.diff


2 Files Affected:

- (modified) clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp (+4-29) 
- (modified) clang/test/Analysis/NewDelete-checker-test.cpp (+2-2) 


``````````diff
diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
index 0a58d7cc2635a..be8f89853bc96 100644
--- a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -346,10 +346,6 @@ namespace {
   };
 
 BUGTYPE_PROVIDER(DoubleFree, "Double free")
-// TODO: Remove DoubleDelete as a separate bug type and when it would be
-// emitted, emit DoubleFree reports instead. (Note that DoubleFree is already
-// used for all allocation families, not just malloc/free.)
-BUGTYPE_PROVIDER(DoubleDelete, "Double delete")
 
 struct Leak : virtual public CheckerFrontend {
   // Leaks should not be reported if they are post-dominated by a sink:
@@ -410,7 +406,7 @@ class MallocChecker
   DynMemFrontend<DoubleFree, Leak, UseFree, BadFree, FreeAlloca, OffsetFree,
                  UseZeroAllocated>
       MallocChecker;
-  DynMemFrontend<DoubleFree, DoubleDelete, UseFree, BadFree, OffsetFree,
+  DynMemFrontend<DoubleFree, UseFree, BadFree, OffsetFree,
                  UseZeroAllocated>
       NewDeleteChecker;
   DynMemFrontend<Leak> NewDeleteLeaksChecker;
@@ -848,8 +844,6 @@ class MallocChecker
   void HandleDoubleFree(CheckerContext &C, SourceRange Range, bool Released,
                         SymbolRef Sym, SymbolRef PrevSym) const;
 
-  void HandleDoubleDelete(CheckerContext &C, SymbolRef Sym) const;
-
   void HandleUseZeroAlloc(CheckerContext &C, SourceRange Range,
                           SymbolRef Sym) const;
 
@@ -2737,7 +2731,8 @@ void MallocChecker::HandleDoubleFree(CheckerContext &C, SourceRange Range,
         (Released ? "Attempt to free released memory"
                   : "Attempt to free non-owned memory"),
         N);
-    R->addRange(Range);
+    if (Range.isValid())
+      R->addRange(Range);
     R->markInteresting(Sym);
     if (PrevSym)
       R->markInteresting(PrevSym);
@@ -2746,26 +2741,6 @@ void MallocChecker::HandleDoubleFree(CheckerContext &C, SourceRange Range,
   }
 }
 
-void MallocChecker::HandleDoubleDelete(CheckerContext &C, SymbolRef Sym) const {
-  const DoubleDelete *Frontend = getRelevantFrontendAs<DoubleDelete>(C, Sym);
-  if (!Frontend)
-    return;
-  if (!Frontend->isEnabled()) {
-    C.addSink();
-    return;
-  }
-
-  if (ExplodedNode *N = C.generateErrorNode()) {
-
-    auto R = std::make_unique<PathSensitiveBugReport>(
-        Frontend->DoubleDeleteBug, "Attempt to delete released memory", N);
-
-    R->markInteresting(Sym);
-    R->addVisitor<MallocBugVisitor>(Sym);
-    C.emitReport(std::move(R));
-  }
-}
-
 void MallocChecker::HandleUseZeroAlloc(CheckerContext &C, SourceRange Range,
                                        SymbolRef Sym) const {
   const UseZeroAllocated *Frontend =
@@ -3324,7 +3299,7 @@ void MallocChecker::checkUseZeroAllocated(SymbolRef Sym, CheckerContext &C,
 bool MallocChecker::checkDoubleDelete(SymbolRef Sym, CheckerContext &C) const {
 
   if (isReleased(Sym, C)) {
-    HandleDoubleDelete(C, Sym);
+    HandleDoubleFree(C, SourceRange(), /*Released=*/true, Sym, nullptr);
     return true;
   }
   return false;
diff --git a/clang/test/Analysis/NewDelete-checker-test.cpp b/clang/test/Analysis/NewDelete-checker-test.cpp
index da0eef7c52bd8..7c3e142d586bb 100644
--- a/clang/test/Analysis/NewDelete-checker-test.cpp
+++ b/clang/test/Analysis/NewDelete-checker-test.cpp
@@ -412,7 +412,7 @@ class DerefClass{
 void testDoubleDeleteClassInstance() {
   DerefClass *foo = new DerefClass();
   delete foo;
-  delete foo; // newdelete-warning {{Attempt to delete released memory}}
+  delete foo; // newdelete-warning {{Attempt to free released memory}}
 }
 
 class EmptyClass{
@@ -424,7 +424,7 @@ class EmptyClass{
 void testDoubleDeleteEmptyClass() {
   EmptyClass *foo = new EmptyClass();
   delete foo;
-  delete foo; // newdelete-warning {{Attempt to delete released memory}}
+  delete foo; // newdelete-warning {{Attempt to free released memory}}
 }
 
 struct Base {

``````````

</details>


https://github.com/llvm/llvm-project/pull/147542