Merge pull request ewasm#2 from WebAssembly/high-level-goals-2

Update high-level goals, and add post-v1 features.

EssentialPostV1Features.md

@@ -1,21 +1,51 @@
 # Essential Post-v.1 Features
 
 This is a list of essential features we *know* we need but were not part of the
-Minimum Viable Product that is [v.1](V1.md).
+Minimum Viable Product that is [v.1](V1.md). These will be developed following
+the [high-level goals](HighLevelGoals.md), and prioritized based on developer
+feedback.
+
 
 *This is just a skeleton list to start a discussion*
 
+## 64-bit integers
+* TODO
+
 ## Threads
+* Atomics
+* Futex or [synchronic][]
+* Thread-local storage
+
+  [synchronic]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4195.pdf
+
+## Fixed-width SIMD
 * TODO
 
-## Zero-cost Exception Handling
+## Dynamic loading
 * TODO
 
-## 64-bit integers
+## Platform-independent Just-in-Time compilatione
 * TODO
+* Potentially through dynamic loading.
+
+## Fine-grained memory management
+* Shared memory
+* `mmap`/`munmap`/`madvise`
+
+## Zero-cost Exception Handling
+* Developer access to stack unwinding and inspection.
 
-## Fixed-width SIMD a la SIMD.js
+## Garbage collection
 * TODO
 
 ## Signature-restricted Proper Tail Calls
 * TODO
+
+## Irreducible control flow
+* TODO
+
+## Extra math
+The following features may not work the same on all platforms:
+* Fused multiply-add.
+* Reciprocal square-root approximate.
+* 16-bit floating-point values.

HighLevelGoals.md

@@ -1,16 +1,27 @@
 # WebAssembly High-Level Goals
 
-1. Define a portable, size- and load-time-efficient binary format to serve as a web compilation target.
-2. Define a human-editable text format that is isomorphic and convertible to/from the binary format.
-3. Design v.1 to allow an effective (load-time and performance) [polyfill](https://github.com/WebAssembly/polyfill) via client-side compilation to [asm.js](http://asmjs.org).
-4. Design v.1 as a Minimum Viable Product: basically what you can do with [asm.js](http://asmjs.org).
-5. Design to integrate well with the existing web platform:
+1. Define a portable, size- and load-time-efficient binary format to serve as a
+   web compilation target which can be compiled to execute at native speed and
+   take full advantage of a CPU's capabilities.
+2. Define a human-editable text format that is isomorphic and convertible
+   to/from the binary format.
+3. Design to serve as a compilation target for a growing set of source languages
+   over time, starting with C/C++.
+4. Design to maintain the versionless, feature-testing and backwards-compatible
+   evolution story of the web; engines should not need multiple, versioned
+   decoders.
+5. Design and implement incrementally: the initial version will be a Minimum
+   Viable Product by being an effective [polyfill][] via client-side compilation
+   to [asm.js][], with a feature set similar to [asm.js][]'s current
+   features. Subsequent versions will be more
+   [featureful](EssentialPostV1Features.md).
+6. Design to integrate well with the existing web platform:
     * execute in the same semantic universe as JavaScript;
     * allow synchronous calls to and from JavaScript;
-    * enforce the same-origin security policy; and 
-    * access browser functionality through the same Web APIs that are accessible to JavaScript.
-6. Design to maintain the versionless, feature-testing and backwards-compatible evolution story 
-   of the web; engines should not need multiple, versioned decoders.
+    * enforce the same-origin and permissions security policies; and
+    * access browser functionality through the same Web APIs that are accessible
+      to JavaScript.
 7. Design to allow execution in non-browser environments.
 
-
+  [polyfill]: https://github.com/WebAssembly/polyfill
+  [asm.js]: http://asmjs.org