[MemProf] Include caller clone information in dot graph nodes

We already included the assigned clone of the callsite node's callee in
the dot graph after function assignment. This adds the same information
for the enclosing caller function to aid debugging.

Author: teresajohnson

llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp

@@ -2073,14 +2073,14 @@ std::string IndexCallsiteContextGraph::getLabel(const FunctionSummary *Func,
                                                 unsigned CloneNo) const {
   auto VI = FSToVIMap.find(Func);
   assert(VI != FSToVIMap.end());
+  auto CallerName = getMemProfFuncName(VI->second.name(), CloneNo);
   if (isa<AllocInfo *>(Call))
-    return (VI->second.name() + " -> alloc").str();
+    return CallerName + " -> alloc";
   else {
     auto *Callsite = dyn_cast_if_present<CallsiteInfo *>(Call);
-    return (VI->second.name() + " -> " +
-            getMemProfFuncName(Callsite->Callee.name(),
-                               Callsite->Clones[CloneNo]))
-        .str();
+    return CallerName + " -> " +
+           getMemProfFuncName(Callsite->Callee.name(),
+                              Callsite->Clones[CloneNo]);
   }
 }
 

llvm/test/ThinLTO/X86/memprof-basic.ll

@@ -52,6 +52,7 @@
 ; RUN:	cat %t.ccg.postbuild.dot | FileCheck %s --check-prefix=DOT
 ;; We should have cloned bar, baz, and foo, for the cold memory allocation.
 ; RUN:	cat %t.ccg.cloned.dot | FileCheck %s --check-prefix=DOTCLONED
+; RUN:	cat %t.ccg.clonefuncassign.dot | FileCheck %s --check-prefix=DOTFUNCASSIGN
 
 ; RUN: llvm-dis %t.out.1.4.opt.bc -o - | FileCheck %s --check-prefix=IR
 
@@ -370,6 +371,8 @@ attributes #0 = { noinline optnone }
 ; DOTCLONED: 	Node[[BAR2]] [shape=record,tooltip="N[[BAR2]] ContextIds: 2",fillcolor="cyan",color="blue",style="filled,bold,dashed",label="{OrigId: Alloc0\n_Z3barv -\> alloc}"];
 ; DOTCLONED: }
 
+; DOTFUNCASSIGN: _Z3bazv.memprof.1 -\> _Z3barv.memprof.1
+; DOTFUNCASSIGN: _Z3barv.memprof.1 -\> alloc
 
 ; DISTRIB: ^[[BAZ:[0-9]+]] = gv: (guid: 1807954217441101578, {{.*}} callsites: ((callee: ^[[BAR:[0-9]+]], clones: (0, 1)
 ; DISTRIB: ^[[FOO:[0-9]+]] = gv: (guid: 8107868197919466657, {{.*}} callsites: ((callee: ^[[BAZ]], clones: (0, 1)