https://bugs.gentoo.org/show_bug.cgi?id=403519
http://llvm.org/viewvc/llvm-project?view=rev&revision=153938

--- llvm/trunk/lib/Target/PowerPC/PPCJITInfo.cpp	2011/06/15 15:29:47	133059
+++ llvm/trunk/lib/Target/PowerPC/PPCJITInfo.cpp	2012/04/03 06:59:28	153938
@@ -291,9 +291,10 @@
 }
 #endif
 
-extern "C" void *PPCCompilationCallbackC(unsigned *StubCallAddrPlus4,
-                                         unsigned *OrigCallAddrPlus4,
-                                         bool is64Bit) {
+extern "C" {
+static void* LLVM_ATTRIBUTE_USED PPCCompilationCallbackC(unsigned *StubCallAddrPlus4,
+                                                         unsigned *OrigCallAddrPlus4,
+                                                         bool is64Bit) {
   // Adjust the pointer to the address of the call instruction in the stub
   // emitted by emitFunctionStub, rather than the instruction after it.
   unsigned *StubCallAddr = StubCallAddrPlus4 - 1;
@@ -337,6 +338,7 @@
   // stack after we restore all regs.
   return Target;
 }
+}