commit cb359df81b83dd4f938d05cb9cf5c34bd20068bd
author Douglas Gregor <dgregor@apple.com> Thu May 20 05:54:35 2010 +0000
committer Douglas Gregor <dgregor@apple.com> Thu May 20 05:54:35 2010 +0000
tree ca7dd714acdc7525b44b293bc64e47a6578863ea
parent 47e8e399d25a976345a7bf07dc6c5b5fcb811740

When creating a this-adjustment thunk where the return value is of C++
class type (that uses a return slot), pass the return slot to the
callee directly rather than allocating new storage and trying to copy
the object. This appears to have been the cause of the remaining two
Boost.Interprocess failures.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104215 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGVTables.cpp

diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp
index 368e248..3c9b45b 100644
--- a/lib/CodeGen/CGVTables.cpp
+++ b/lib/CodeGen/CGVTables.cpp
@@ -2657,8 +2657,15 @@
     CGM.getTypes().getFunctionInfo(ResultType, CallArgs,
                                    FPT->getExtInfo());
   
+  // Determine whether we have a return value slot to use.
+  ReturnValueSlot Slot;
+  if (!ResultType->isVoidType() &&
+      FnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
+      hasAggregateLLVMType(CurFnInfo->getReturnType()))
+    Slot = ReturnValueSlot(ReturnValue, ResultType.isVolatileQualified());
+  
   // Now emit our call.
-  RValue RV = EmitCall(FnInfo, Callee, ReturnValueSlot(), CallArgs, MD);
+  RValue RV = EmitCall(FnInfo, Callee, Slot, CallArgs, MD);
   
   if (!Thunk.Return.isEmpty()) {
     // Emit the return adjustment.
@@ -2701,7 +2708,7 @@
     RV = RValue::get(ReturnValue);
   }
 
-  if (!ResultType->isVoidType())
+  if (!ResultType->isVoidType() && Slot.isNull())
     EmitReturnOfRValue(RV, ResultType);
 
   FinishFunction();

test/CodeGenCXX/thunks.cpp

diff --git a/test/CodeGenCXX/thunks.cpp b/test/CodeGenCXX/thunks.cpp
index 7d2edaa..8144770 100644
--- a/test/CodeGenCXX/thunks.cpp
+++ b/test/CodeGenCXX/thunks.cpp
@@ -86,10 +86,6 @@
 
 }
 
-// This is from Test5:
-// CHECK: define linkonce_odr void @_ZTv0_n24_N5Test51B1fEv
-// CHECK: define internal void @_ZThn8_N12_GLOBAL__N_11C1fEv(
-
 // Check that the thunk gets internal linkage.
 namespace {
 
@@ -134,4 +130,49 @@
 }
 }
 
+namespace Test6 {
+  struct X {
+    X();
+    X(const X&);
+    X &operator=(const X&);
+    ~X();
+  };
 
+  struct P {
+    P();
+    P(const P&);
+    ~P();
+    X first;
+    X second;
+  };
+
+  P getP();
+
+  struct Base1 {
+    int i;
+
+    virtual X f() { return X(); }
+  };
+
+  struct Base2 {
+    float real;
+
+    virtual X f() { return X(); }
+  };
+
+  struct Thunks : Base1, Base2 {
+    long l;
+
+    virtual X f();
+  };
+
+  // CHECK: define void @_ZThn16_N5Test66Thunks1fEv
+  // CHECK-NOT: memcpy
+  // CHECK: {{call void @_ZN5Test66Thunks1fEv.*sret}}
+  // CHECK: ret void
+  X Thunks::f() { return X(); }
+}
+
+// This is from Test5:
+// CHECK: define linkonce_odr void @_ZTv0_n24_N5Test51B1fEv
+// CHECK: define internal void @_ZThn8_N12_GLOBAL__N_11C1fEv(