commit e67a575dfb38acb02c25d583691603ca7cd883a5
author Artem Dergachev <artem.dergachev@gmail.com> Tue Dec 12 02:59:09 2017 +0000
committer Artem Dergachev <artem.dergachev@gmail.com> Tue Dec 12 02:59:09 2017 +0000
tree 45a1f2ec75cc474d95cbdfac1fa52ce7883b6482
parent 074f858da7440f8ffd438ffe0f26e74ac8e37f9f

[analyzer] StackAddrEscape: For now, disable the new async escape checks.

The new check introduced in r318705 is useful, but suffers from a particular
class of false positives, namely, it does not account for
dispatch_barrier_sync() API which allows one to ensure that the asyncronously
executed block that captures a pointer to a local variable does not actually
outlive that variable.

The new check is split into a separate checker, under the name of
alpha.core.StackAddressAsyncEscape, which is likely to get enabled by default
again once these positives are fixed. The rest of the StackAddressEscapeChecker
is still enabled by default.

Differential Revision: https://reviews.llvm.org/D41042

llvm-svn: 320455

clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp

diff --git a/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
index 94cdd30..2597562 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StackAddrEscapeChecker.cpp
@@ -37,6 +37,14 @@
   mutable std::unique_ptr<BuiltinBug> BT_capturedstackret;
 
 public:
+  enum CheckKind {
+    CK_StackAddrEscapeChecker,
+    CK_StackAddrAsyncEscapeChecker,
+    CK_NumCheckKinds
+  };
+
+  DefaultBool ChecksEnabled[CK_NumCheckKinds];
+
   void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
   void checkPreStmt(const ReturnStmt *RS, CheckerContext &C) const;
   void checkEndFunction(CheckerContext &Ctx) const;
@@ -225,6 +233,8 @@
 
 void StackAddrEscapeChecker::checkPreCall(const CallEvent &Call,
                                           CheckerContext &C) const {
+  if (!ChecksEnabled[CK_StackAddrAsyncEscapeChecker])
+    return;
   if (!Call.isGlobalCFunction("dispatch_after") &&
       !Call.isGlobalCFunction("dispatch_async"))
     return;
@@ -237,6 +247,8 @@
 
 void StackAddrEscapeChecker::checkPreStmt(const ReturnStmt *RS,
                                           CheckerContext &C) const {
+  if (!ChecksEnabled[CK_StackAddrEscapeChecker])
+    return;
 
   const Expr *RetE = RS->getRetValue();
   if (!RetE)
@@ -277,6 +289,9 @@
 }
 
 void StackAddrEscapeChecker::checkEndFunction(CheckerContext &Ctx) const {
+  if (!ChecksEnabled[CK_StackAddrEscapeChecker])
+    return;
+
   ProgramStateRef State = Ctx.getState();
 
   // Iterate over all bindings to global variables and see if it contains
@@ -346,6 +361,12 @@
   }
 }
 
-void ento::registerStackAddrEscapeChecker(CheckerManager &Mgr) {
-  Mgr.registerChecker<StackAddrEscapeChecker>();
-}
+#define REGISTER_CHECKER(name) \
+  void ento::register##name(CheckerManager &Mgr) { \
+    StackAddrEscapeChecker *Chk = \
+        Mgr.registerChecker<StackAddrEscapeChecker>(); \
+    Chk->ChecksEnabled[StackAddrEscapeChecker::CK_##name] = true; \
+  }
+
+REGISTER_CHECKER(StackAddrEscapeChecker)
+REGISTER_CHECKER(StackAddrAsyncEscapeChecker)