Introduce `MemoryKind` abstraction

Re-cast the notion of "heap" (in liveness, SSA, and value-numbering) as
one of potentially many `MemoryKind`s, called `GcHeap`.  Update names,
comments, data structures, and signatures as appropriate to parameterize
relevant data/methods over `MemoryKind`.  This change is a no-diff
refactoring, and currently `GcHeap` is the only `MemoryKind`.  Generally,
codepaths which will generically need to process all `MemoryKinds`s
(initializing, dumping, dataflow propagation) now iterate over all
`MemoryKinds`, and codepaths which are sensitive to the semantics of the
specific `MemoryKind` (def/use identification in liveness and value
numbering) are changed to specifically operate on `MemoryKind::GcHeap`.

One notable exception is that `lvMemoryPerSsaData` and `CountForMemoryDef`
are *not* parameterized over `MemoryKind`; there's a single "space" of SSA
defnums for memory defs (though the same tree can incur different defs for
different memory kinds [in which case their defnums will differ]), to
facilitate subsequently sharing SSA nodes across memory kinds when
appropriate.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/jit/valuenum.h b/src/jit/valuenum.h
index c8a57ff210..e0443dc18c 100644
--- a/src/jit/valuenum.h
+++ b/src/jit/valuenum.h
@@ -217,7 +217,7 @@ private:
 
 #ifdef DEBUG
     // This helps test some performance pathologies related to "evaluation" of VNF_MapSelect terms,
-    // especially relating to the heap.  We count the number of applications of such terms we consider,
+    // especially relating to the GcHeap.  We count the number of applications of such terms we consider,
     // and if this exceeds a limit, indicated by a COMPlus_ variable, we assert.
     unsigned m_numMapSels;
 #endif
@@ -762,7 +762,7 @@ public:
     // the function application it represents; otherwise, return "false."
     bool GetVNFunc(ValueNum vn, VNFuncApp* funcApp);
 
-    // Requires that "vn" represents a "heap address" the sum of a "TYP_REF" value and some integer
+    // Requires that "vn" represents a "GC heap address" the sum of a "TYP_REF" value and some integer
     // value.  Returns the TYP_REF value.
     ValueNum VNForRefInAddr(ValueNum vn);