IR: Eliminate non-determinism in the module summary analysis.

Also make the summary ref and call graph vectors immutable. This means
a smaller API surface and fewer places to audit for non-determinism.

Differential Revision: https://reviews.llvm.org/D27875

llvm-svn: 290200
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 8f23e31..7984292 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3290,21 +3290,11 @@
   NameVals.push_back(FS->instCount());
   NameVals.push_back(FS->refs().size());
 
-  unsigned SizeBeforeRefs = NameVals.size();
   for (auto &RI : FS->refs())
     NameVals.push_back(VE.getValueID(RI.getValue()));
-  // Sort the refs for determinism output, the vector returned by FS->refs() has
-  // been initialized from a DenseSet.
-  std::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
 
-  std::vector<FunctionSummary::EdgeTy> Calls = FS->calls();
-  std::sort(Calls.begin(), Calls.end(),
-            [this](const FunctionSummary::EdgeTy &L,
-                   const FunctionSummary::EdgeTy &R) {
-              return getValueId(L.first) < getValueId(R.first);
-            });
   bool HasProfileData = F.getEntryCount().hasValue();
-  for (auto &ECI : Calls) {
+  for (auto &ECI : FS->calls()) {
     NameVals.push_back(getValueId(ECI.first));
     if (HasProfileData)
       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));