[PATCH] D43144: [analyzer] Implement path notes for temporary destructors.

Artem Dergachev via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Fri Feb 9 14:35:25 PST 2018


NoQ updated this revision to Diff 133687.
NoQ added a comment.

Minor indent fix.


https://reviews.llvm.org/D43144

Files:
  lib/StaticAnalyzer/Core/PathDiagnostic.cpp
  test/Analysis/inlining/temp-dtors-path-notes.cpp


Index: test/Analysis/inlining/temp-dtors-path-notes.cpp
===================================================================
--- /dev/null
+++ test/Analysis/inlining/temp-dtors-path-notes.cpp
@@ -0,0 +1,46 @@
+// RUN: %clang_analyze_cc1 -analyze -analyzer-checker core -analyzer-config cfg-temporary-dtors=true -analyzer-output=text -verify %s
+
+namespace test_simple_temporary {
+class C {
+  int x;
+
+public:
+  C(int x): x(x) {} // expected-note{{The value 0 is assigned to field 'x'}}
+  ~C() { x = 1 / x; } // expected-warning{{Division by zero}}
+                      // expected-note at -1{{Division by zero}}
+};
+
+void test() {
+  C(0); // expected-note   {{Passing the value 0 via 1st parameter 'x'}}
+        // expected-note at -1{{Calling constructor for 'C'}}
+        // expected-note at -2{{Returning from constructor for 'C'}}
+        // expected-note at -3{{Calling '~C'}}
+}
+} // end namespace test_simple_temporary
+
+namespace test_lifetime_extended_temporary {
+class C {
+  int x;
+
+public:
+  C(int x): x(x) {} // expected-note{{The value 0 is assigned to field 'x'}}
+  void nop() const {}
+  ~C() { x = 1 / x; } // expected-warning{{Division by zero}}
+                      // expected-note at -1{{Division by zero}}
+};
+
+void test(int coin) {
+  // We'd divide by zero in the temporary destructor that goes after the
+  // elidable copy-constructor from C(0) to the lifetime-extended temporary.
+  // So in fact this example has nothing to do with lifetime extension.
+  // Actually, it would probably be better to elide the constructor, and
+  // put the note for the destructor call at the closing brace after nop.
+  const C &c = coin ? C(1) : C(0); // expected-note   {{Assuming 'coin' is 0}}
+                                   // expected-note at -1{{'?' condition is false}}
+                                   // expected-note at -2{{Passing the value 0 via 1st parameter 'x'}}
+                                   // expected-note at -3{{Calling constructor for 'C'}}
+                                   // expected-note at -4{{Returning from constructor for 'C'}}
+                                   // expected-note at -5{{Calling '~C'}}
+  c.nop();
+}
+} // end namespace test_lifetime_extended_temporary
Index: lib/StaticAnalyzer/Core/PathDiagnostic.cpp
===================================================================
--- lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -579,8 +579,14 @@
     const CFGNewAllocator &Alloc = Source.castAs<CFGNewAllocator>();
     return PathDiagnosticLocation(Alloc.getAllocatorExpr(), SM, CallerCtx);
   }
-  case CFGElement::TemporaryDtor:
-    llvm_unreachable("not yet implemented!");
+  case CFGElement::TemporaryDtor: {
+    // Temporary destructors are for temporaries. They die immediately at around
+    // the location of CXXBindTemporaryExpr. If they are lifetime-extended,
+    // they'd be dealt with via an AutomaticObjectDtor instead.
+    const CFGTemporaryDtor &Dtor = Source.castAs<CFGTemporaryDtor>();
+    return PathDiagnosticLocation::createEnd(Dtor.getBindTemporaryExpr(), SM,
+                                             CallerCtx);
+  }
   case CFGElement::LifetimeEnds:
   case CFGElement::LoopExit:
     llvm_unreachable("CFGElement kind should not be on callsite!");


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