From 186af2de86aea41d7418158e68f96c1f8620e013 Mon Sep 17 00:00:00 2001
From: DeLesley Hutchins <delesley@google.com>
Date: Thu, 20 Sep 2012 22:18:02 +0000
Subject: [PATCH] Thread safety analysis: properly canonicalize calls to
 virtual methods within lock expressions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164324 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/ThreadSafety.cpp                | 20 +++++++++---
 test/SemaCXX/warn-thread-safety-analysis.cpp | 32 ++++++++++++++++++++
 2 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/lib/Analysis/ThreadSafety.cpp b/lib/Analysis/ThreadSafety.cpp
index 036d0b8888..fd59556665 100644
--- a/lib/Analysis/ThreadSafety.cpp
+++ b/lib/Analysis/ThreadSafety.cpp
@@ -226,8 +226,21 @@ private:
     return NodeVec.size()-1;
   }
 
-  unsigned makeMCall(unsigned NumArgs, const NamedDecl *D) {
-    NodeVec.push_back(SExprNode(EOP_MCall, NumArgs, D));
+  // Grab the very first declaration of virtual method D
+  const CXXMethodDecl* getFirstVirtualDecl(const CXXMethodDecl *D) {
+    while (true) {
+      D = D->getCanonicalDecl();
+      CXXMethodDecl::method_iterator I = D->begin_overridden_methods(),
+                                     E = D->end_overridden_methods();
+      if (I == E)
+        return D;  // Method does not override anything
+      D = *I;      // FIXME: this does not work with multiple inheritance.
+    }
+    return 0;
+  }
+
+  unsigned makeMCall(unsigned NumArgs, const CXXMethodDecl *D) {
+    NodeVec.push_back(SExprNode(EOP_MCall, NumArgs, getFirstVirtualDecl(D)));
     return NodeVec.size()-1;
   }
 
@@ -328,8 +341,7 @@ private:
         return buildSExpr(CMCE->getImplicitObjectArgument(), CallCtx, NDeref);
       }
       unsigned NumCallArgs = CMCE->getNumArgs();
-      unsigned Root =
-        makeMCall(NumCallArgs, CMCE->getMethodDecl()->getCanonicalDecl());
+      unsigned Root = makeMCall(NumCallArgs, CMCE->getMethodDecl());
       unsigned Sz = buildSExpr(CMCE->getImplicitObjectArgument(), CallCtx);
       Expr** CallArgs = CMCE->getArgs();
       for (unsigned i = 0; i < NumCallArgs; ++i) {
diff --git a/test/SemaCXX/warn-thread-safety-analysis.cpp b/test/SemaCXX/warn-thread-safety-analysis.cpp
index 0d6aa4c79b..c45adb6f0c 100644
--- a/test/SemaCXX/warn-thread-safety-analysis.cpp
+++ b/test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -3453,3 +3453,35 @@ void test3() EXCLUSIVE_LOCKS_REQUIRED(fatalmu_) {
 }
 
 }   // end namespace UnreachableExitTest
+
+
+namespace VirtualMethodCanonicalizationTest {
+
+class Base {
+public:
+  virtual Mutex* getMutex() = 0;
+};
+
+class Base2 : public Base {
+public:
+  Mutex* getMutex();
+};
+
+class Base3 : public Base2 {
+public:
+  Mutex* getMutex();
+};
+
+class Derived : public Base3 {
+public:
+  Mutex* getMutex();  // overrides Base::getMutex()
+};
+
+void baseFun(Base *b) EXCLUSIVE_LOCKS_REQUIRED(b->getMutex()) { }
+
+void derivedFun(Derived *d) EXCLUSIVE_LOCKS_REQUIRED(d->getMutex()) {
+  baseFun(d);
+}
+
+}  // end namespace VirtualMethodCanonicalizationTest
+
-- 
2.40.0