From: Anders Carlsson <andersca@mac.com>
Date: Mon, 12 Oct 2009 19:41:04 +0000 (+0000)
Subject: Factor out devirtualization checking into a separate function and make it handle... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8e7670de19334eccfe9ac5fc70fa57015b1654c8;p=clang

Factor out devirtualization checking into a separate function and make it handle references correctly.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83880 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index af49942738..0744b79d45 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -198,6 +198,20 @@ RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD,
                   Callee, Args, MD);
 }
 
+/// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given
+/// expr can be devirtualized.
+static bool canDevirtualizeMemberFunctionCalls(const Expr *Base) {
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
+    if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
+      // This is a record decl. We know the type and can devirtualize it.
+      return VD->getType()->isRecordType();
+    }
+  }
+  
+  // We can't devirtualize the call.
+  return false;
+}
+
 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE) {
   if (isa<BinaryOperator>(CE->getCallee())) 
     return EmitCXXMemberPointerCallExpr(CE);
@@ -235,7 +249,7 @@ RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE) {
   // because then we know what the type is.
   llvm::Value *Callee;
   if (MD->isVirtual() && !ME->hasQualifier() && 
-      !ME->getBase()->getType()->isRecordType())
+      !canDevirtualizeMemberFunctionCalls(ME->getBase()))
     Callee = BuildVirtualCall(MD, This, Ty);
   else if (const CXXDestructorDecl *Destructor
              = dyn_cast<CXXDestructorDecl>(MD))
diff --git a/test/CodeGenCXX/devirtualize-virtual-function-calls.cpp b/test/CodeGenCXX/devirtualize-virtual-function-calls.cpp
new file mode 100644
index 0000000000..19206aebce
--- /dev/null
+++ b/test/CodeGenCXX/devirtualize-virtual-function-calls.cpp
@@ -0,0 +1,18 @@
+// RUN: clang-cc %s -emit-llvm -o - | FileCheck %s
+
+struct A {
+  virtual void f();
+};
+
+void f(A a, A *ap, A& ar) {
+  // This should not be a virtual function call.
+  
+  // CHECK: call void @_ZN1A1fEv(%struct.A* %a)
+  a.f();
+
+  // CHECK: call void %  
+  ap->f();
+
+  // CHECK: call void %  
+  ar.f();
+}
diff --git a/test/CodeGenCXX/virtual-function-calls.cpp b/test/CodeGenCXX/virtual-function-calls.cpp
index 34ab1df689..d27a7c9bfc 100644
--- a/test/CodeGenCXX/virtual-function-calls.cpp
+++ b/test/CodeGenCXX/virtual-function-calls.cpp
@@ -8,10 +8,3 @@ struct A {
 void f(A *a) {
   a->f('c');
 }
-
-void f(A a) {
-  // This should not be a virtual function call.
-  
-  // CHECK: call void @_ZN1A1fEc
-  a.f('c');
-}
\ No newline at end of file