kripken

#include <emscripten.h>

extern void launch_missiles();

extern void foo_checkin();
extern void bar_checkin();

void (*mutable_global)() = &launch_missiles;

void benign() {}

kripken

--- a.out.js	2024-01-31 09:42:57.311326787 -0800
+++ b.out.js	2024-01-31 09:43:14.131501278 -0800
@@ -1,40 +1,38 @@
 var Module = typeof Module != "undefined" ? Module : {};
 
 var moduleOverrides = Object.assign({}, Module);
 
 var arguments_ = [];
 
 var thisProgram = "./this.program";

kripken

diff --git a/test/lit/passes/once-reduction.wast b/test/lit/passes/once-reduction.wast
index dd15da5da..7feae8857 100644
--- a/test/lit/passes/once-reduction.wast
+++ b/test/lit/passes/once-reduction.wast
@@ -1349,311 +1349,311 @@
 )
 
 ;; Corner case: Exported mutable global. We cannot optimize it, since the
 ;; outside may read and write it.
 (module

kripken

// Compile with e.g.
//
//   ./emcc a.cpp -pthread -sPROXY_TO_PTHREAD -O3 -s INITIAL_MEMORY=1GB
//

#include <atomic>
#include <stdio.h>
#include <stdlib.h>
#include <emscripten.h>
#include <emscripten/threading.h>

kripken

diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index dec9249c3..b56348b31 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -42,70 +42,76 @@ int unhex(char c) {
   }
   if (c >= 'A' && c <= 'F') {
     return c - 'A' + 10;
   }
   throw wasm::ParseException("invalid hexadecimal");

kripken

<script>
  var module = WebAssembly.instantiateStreaming(fetch("linked_list.wasm"), {});
</script>

kripken

var Module = typeof Module != "undefined" ? Module : {};

(function() {
 return this;
}())["Module"] = function() {
 var moduleOverrides = Object.assign({}, Module);
 var arguments_ = [];
 var thisProgram = "./this.program";
 var quit_ = (status, toThrow) => {
  throw toThrow;

kripken

[package]
name = "fannkuch"
version = "0.1.0"
edition = "2021"

[profile.release]
lto = "yes"
panic = "abort"
opt-level = "s"

kripken

Trying to avoid quadratic work in 1b

(context: WebAssembly/function-references#44)

An idea I've had is to annotate validated branches. The key thing is that the set of validated branch targets is monotonic - just like the set of set locals. That is, once we see that a branch to $b validates, any subsequent branch must also validate, since we can only add more locals that are set. So as an optimization, the validator could track those until the end of the current block. That basically means to handle the set of valid branch targets in a 1a-like manner, and could be a nice speedup on stuff like this:

  (br_if $b ..) ;; Linear time here.
  (br_if $b ..) ;; But constant time here
  (br_if $b ..) ;; and here!

kripken

Example of Wasm GC non-nullable variations on the "defer" option

Imagine this source code:

func foo() {
  var ref: A = ..some non-null result..;
  bar(ref, ref);
}