Assembler changes for enabling GrowHeap in Wasm

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 2224b9fb12e2363e681bf3c0b711a717ad226929..00e9d93e805ebfe77f1b2eee322b4c9273697dcc 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -385,6 +385,9 @@ class RelocInfo {
     DEBUGGER_STATEMENT,  // Code target for the debugger statement.
     EMBEDDED_OBJECT,
     CELL,
+    // Marker for relocation when the heap changes, used only on wasm code
+    // objects

[Yang, 2016/03/03 06:21:56]

Can you change the comment to say "To relocate pointers into the wasm heap,
embedded in wasm code"? All reloc info are markers of some sort, so that part is
redundant.

[gdeepti1, 2016/03/03 18:00:10]

Done.

+    WASM_HEAP_OBJECT,

[titzer, 2016/03/03 18:11:59]

Can we name this WASM_MEMORY_REFERENCE?

We've been trying to avoid using the term "heap" to refer to the wasm memory.

[gdeepti1, 2016/03/03 22:59:15]

Done.

 
     // Everything after runtime_entry (inclusive) is not GC'ed.
     RUNTIME_ENTRY,
@@ -427,7 +430,7 @@ class RelocInfo {
     FIRST_REAL_RELOC_MODE = CODE_TARGET,
     LAST_REAL_RELOC_MODE = VENEER_POOL,
     LAST_CODE_ENUM = DEBUGGER_STATEMENT,
-    LAST_GCED_ENUM = CELL,
+    LAST_GCED_ENUM = WASM_HEAP_OBJECT,
   };
 
   STATIC_ASSERT(NUMBER_OF_MODES <= kBitsPerInt);
@@ -511,6 +514,9 @@ class RelocInfo {
   static inline bool IsGeneratorContinuation(Mode mode) {
     return mode == GENERATOR_CONTINUATION;
   }
+  static inline bool IsWasmCodeEntry(Mode mode) {

[Yang, 2016/03/03 06:21:56]

This name is misleading. I would have thought that this would be a pointer to
the entry of a wasm code object, instead into the wasm heap. How about
"IsWasmHeapReference"?

[gdeepti1, 2016/03/03 18:00:10]

Name was left over from a previous RelocInfo mode I was using, fixed to be
IsWasmHeapReference.

[titzer, 2016/03/03 18:11:59]

As above, IsWasmMemoryReference, for consistency.

+    return mode == WASM_HEAP_OBJECT;
+  }
   static inline int ModeMask(Mode mode) { return 1 << mode; }
 
   // Accessors