Refactor polyfill quite a bit.

6 files changed, 29 insertions, 26 deletions

diff --git a/AstSemantics.md b/AstSemantics.md
index ee16571..2adb7b8 100644
--- a/AstSemantics.md
+++ b/AstSemantics.md
@@ -248,7 +248,7 @@ immediate use.  The following primitives provide AST nodes that express
 control flow and thus allow more opportunities to build bigger expression trees
 and further reduce `SetLocal`/`GetLocal` usage (which constitute 30-40% of total 
 bytes in the polyfill prototype). Additionally, these primitives are useful 
-building blocks for WebAssembly-generators (including the asm.js polyfill).
+building blocks for WebAssembly-generators (including the JavaScript polyfill).
 
   * Comma - evaluate and ignore the result of the first operand, evaluate and return the second operand
   * Conditional - basically ternary ?: operator
diff --git a/BinaryEncoding.md b/BinaryEncoding.md
index a01f423..e605ea5 100644
--- a/BinaryEncoding.md
+++ b/BinaryEncoding.md
@@ -13,7 +13,7 @@ it as having three layers:
    compression algorithm like gzip to achieve.
    * This is not meant to be standardized, at least not initially, as it can be done with a
      downloaded decompressor that runs as web content on the client, and in particular
-     can be implemented in the polyfill. Not standardizing it leaves the binary
+     can be implemented in a polyfill. Not standardizing it leaves the binary
      encoding as the only thing a WebAssembly implementation is required to implement,
      which is nice. However, if the benefits are shown to be substantial, this will be
      reconsidered in the future.
diff --git a/EssentialPostMVPFeatures.md b/EssentialPostMVPFeatures.md
index fa20eb1..03ce2b2 100644
--- a/EssentialPostMVPFeatures.md
+++ b/EssentialPostMVPFeatures.md
@@ -1,9 +1,10 @@
 # Essential Post-MVP Features
 
-This is a list of essential features that are known to be needed ASAP, but were removed from
-[the MVP](MVP.md) since there was not (yet) a portably-efficient polyfill via asm.js. There is a much bigger
-[list of features](FutureFeatures.md) that will be added after this list, prioritized by feedback and
-experience.
+This is a list of essential features that are known to be needed ASAP, but were
+removed from [the MVP](MVP.md) since there was not (yet) a portably-efficient
+polyfill via JavaScript. There is a much bigger
+[list of features](FutureFeatures.md) that will be added after this list,
+prioritized by feedback and experience.
 
 ## Threads
 * Provide low-level buildings blocks for pthreads-style shared memory: shared memory,
diff --git a/HighLevelGoals.md b/HighLevelGoals.md
index 99653d6..d4b2772 100644
--- a/HighLevelGoals.md
+++ b/HighLevelGoals.md
@@ -6,7 +6,7 @@
 2. Specify and implement incrementally:
     * design [the MVP](MVP.md) of the standard as a Minimum Viable Product with
       roughly the same functionality as [asm.js](http://asmjs.org);
-    * ship an effective [polyfill](MVP.md#polyfill) library for the MVP that
+    * ship an effective [polyfill](Polyfill.md) library for the MVP that
       translates WebAssembly code into JavaScript in the client so that
       WebAssembly MVP can run on existing browsers;
     * ship a follow-up to the MVP which adds several more
diff --git a/MVP.md b/MVP.md
index 1f2d4be..5c36325 100644
--- a/MVP.md
+++ b/MVP.md
@@ -7,9 +7,10 @@ and need, but are post-MVP; these are in a separate [essential post-MVP features
 
 This document explains the contents of the MVP at a high-level.  There are also separate docs with more
 precise descriptions of:
+ * the [polyfill to JavaScript](Polyfill.md)
  * the [AST semantics](AstSemantics.md) 
  * the [binary encoding](BinaryEncoding.md)
- 
+
 ## Modules
 * The primary unit of loadable, executable code is a *module*.
   * In a host environment with ES6 modules (browser, node.js), a WebAssembly
@@ -142,14 +143,6 @@ precise descriptions of:
    * To keep an ArrayBuffer's length immutable, resizing a module's heap detaches any existent ArrayBuffers.
  * See the [AST Semantics heap section](AstSemantics.md#accessing-the-heap) for
    more details.
-
-## Polyfill
- * A working prototype is in the [polyfill repo](https://github.com/WebAssembly/polyfill).
- * Even before browsers ship native support for WebAssembly, users can derive
-   value from the polyfill due to the decreased download size of the
-   [binary encoding](BinaryEncoding.md) and minimal impact on startup performance.
- * To maintain good polyfill performance, the [polyfill library will diverge](Polyfill.md#polyfill-deviations)
-   from the specified WebAssembly semantics in certain corner case scenarios.
  
 ## Non-browser embedding
  * Host environments can define builtin modules that are implemented natively but can otherwise
diff --git a/Polyfill.md b/Polyfill.md
index eb51fcf..66bc6fb 100644
--- a/Polyfill.md
+++ b/Polyfill.md
@@ -1,19 +1,28 @@
-# Polyfill to asm.js
+# Polyfill to JavaScript
 
-Even before browsers ship native support for WebAssembly, users can derive
-value from a polyfill to asm.js due to the decreased download size of the
-[binary encoding](BinaryEncoding.md) and minimal impact on startup performance.
-This also allows us to experiment on the early binary encoding and get
-developer feedback before finalizing the format and supporting it natively.
+Even before browsers ship native support for WebAssembly, users can derive value
+from a [polyfill](https://remysharp.com/2010/10/08/what-is-a-polyfill) to
+JavaScript due to:
 
-A working prototype to unpack the WebAssembly binary format into asm.js is in
-the [polyfill repo](https://github.com/WebAssembly/polyfill).
+* Decreased download size of the [binary encoding](BinaryEncoding.md);
+* Minimal impact on startup performance;
+* Building on existing proven approaches of running compiled C++ on the web with
+  good performance, such as through [asm.js](http://asmjs.org).
+
+This polyfill further allows us to experiment on the early binary encoding and
+get developer feedback before finalizing the format and supporting it natively
+as part of [MVP](MVP.md).
+
+A working prototype to unpack the WebAssembly binary format into JavaScript is
+in the [polyfill repo](https://github.com/WebAssembly/polyfill). We leave open
+the possibility of multiple polyfills existing to meet different developers'
+needs.
 
 ## Polyfill Deviations
 
 A polyfill doesn't need to be 100% correct with respect to the WebAssembly
-specification to be useful in practice. There are corner cases (which
-generally fall into undefined behavior in C/C++) where asm.js does not have
+specification to be useful in practice. There are corner cases (which generally
+fall into undefined behavior in C/C++) where JavaScript and asm.js don't have
 ideal semantics to maintain correctness.
 
 To maintain good polyfill performance, the polyfill library will purposely