Flattening rewrite (#1201)

Rename flatten-control-flow to flatten, which now flattens everything, not just control flow, so e.g.

(i32.add
  (call $x)
  (call $y)
)
==>
(block
  (set_local $temp_x (call $x))
  (set_local $temp_y (call $y))
  (i32.add
    (get_local $x)
    (get_local $y)
  )
)

This uses more locals than before, but is much simpler and avoids a bunch of corner cases and fuzz bugs the old one hit. We can optimize later if necessary.

1 files changed, 84 insertions, 13 deletions

diff --git a/test/wasm2asm.traps.js b/test/wasm2asm.traps.js
index 4b89f5b89..2f4ddb0d9 100644
--- a/test/wasm2asm.traps.js
+++ b/test/wasm2asm.traps.js
@@ -19,50 +19,121 @@ function asmFunc(global, env, buffer) {
  function $$1(x, y) {
   x = x | 0;
   y = y | 0;
-  return x + y | 0 | 0;
+  var $$2 = 0, $$3 = 0, $$4 = 0;
+  $$2 = x;
+  $$3 = y;
+  $$4 = $$2 + $$3 | 0;
+  return $$4 | 0;
  }
  
  function $$2(x, y) {
   x = x | 0;
   y = y | 0;
-  return (x | 0) / (y | 0) | 0 | 0;
+  var $$2 = 0, $$3 = 0, $$4 = 0;
+  $$2 = x;
+  $$3 = y;
+  $$4 = ($$2 | 0) / ($$3 | 0) | 0;
+  return $$4 | 0;
  }
  
  function __wasm_ctz_i32(x) {
   x = x | 0;
-  var $$1 = 0;
-  if ((x | 0) == (0 | 0)) $$1 = 32; else $$1 = 31 - Math_clz32(x ^ (x - 1 | 0) | 0) | 0;
-  return $$1 | 0;
+  var $$1 = 0, $$2 = 0, $$3 = 0, $$4 = 0, $$5 = 0, $$6 = 0, $$7 = 0, $$8 = 0, $$9 = 0, $$10 = 0;
+  $$1 = x;
+  $$2 = ($$1 | 0) == (0 | 0);
+  if ($$2) $$9 = 32; else {
+   $$3 = x;
+   $$4 = x;
+   $$5 = $$4 - 1 | 0;
+   $$6 = $$3 ^ $$5 | 0;
+   $$7 = Math_clz32($$6);
+   $$8 = 31 - $$7 | 0;
+   $$9 = $$8;
+  }
+  $$10 = $$9;
+  return $$10 | 0;
  }
  
  function __wasm_popcnt_i32(x) {
   x = x | 0;
-  var count = 0, $$2 = 0, $$3 = 0;
+  var count = 0, $$2 = 0, $$3 = 0, $$4 = 0, $$5 = 0, $$6 = 0, $$7 = 0, $$8 = 0, $$9 = 0, $$10 = 0, $$11 = 0, $$12 = 0, $$13 = 0, $$14 = 0, $$15 = 0;
   count = 0;
   b : {
    l : do {
     $$2 = count;
-    if ((x | 0) == (0 | 0)) break b;
-    x = x & (x - 1 | 0) | 0;
-    count = count + 1 | 0;
+    $$3 = x;
+    $$4 = ($$3 | 0) == (0 | 0);
+    $$5 = $$2;
+    if ($$4) break b;
+    $$6 = $$5;
+    $$7 = x;
+    $$8 = x;
+    $$9 = $$8 - 1 | 0;
+    $$10 = $$7 & $$9 | 0;
+    x = $$10;
+    $$11 = count;
+    $$12 = $$11 + 1 | 0;
+    count = $$12;
     continue l;
     break l;
    } while (1);
   };
-  $$3 = $$2;
-  return $$3 | 0;
+  $$13 = $$5;
+  $$14 = $$13;
+  $$15 = $$14;
+  return $$15 | 0;
  }
  
  function __wasm_rotl_i32(x, k) {
   x = x | 0;
   k = k | 0;
-  return ((4294967295 >>> (k & 31 | 0) | 0) & x | 0) << (k & 31 | 0) | 0 | (((4294967295 << (32 - (k & 31 | 0) | 0) | 0) & x | 0) >>> (32 - (k & 31 | 0) | 0) | 0) | 0 | 0;
+  var $$2 = 0, $$3 = 0, $$4 = 0, $$5 = 0, $$6 = 0, $$7 = 0, $$8 = 0, $$9 = 0, $$10 = 0, $$11 = 0, $$12 = 0, $$13 = 0, $$14 = 0, $$15 = 0, $$16 = 0, $$17 = 0, $$18 = 0, $$19 = 0, $$20 = 0;
+  $$2 = k;
+  $$3 = $$2 & 31 | 0;
+  $$4 = 4294967295 >>> $$3 | 0;
+  $$5 = x;
+  $$6 = $$4 & $$5 | 0;
+  $$7 = k;
+  $$8 = $$7 & 31 | 0;
+  $$9 = $$6 << $$8 | 0;
+  $$10 = k;
+  $$11 = $$10 & 31 | 0;
+  $$12 = 32 - $$11 | 0;
+  $$13 = 4294967295 << $$12 | 0;
+  $$14 = x;
+  $$15 = $$13 & $$14 | 0;
+  $$16 = k;
+  $$17 = $$16 & 31 | 0;
+  $$18 = 32 - $$17 | 0;
+  $$19 = $$15 >>> $$18 | 0;
+  $$20 = $$9 | $$19 | 0;
+  return $$20 | 0;
  }
  
  function __wasm_rotr_i32(x, k) {
   x = x | 0;
   k = k | 0;
-  return ((4294967295 << (k & 31 | 0) | 0) & x | 0) >>> (k & 31 | 0) | 0 | (((4294967295 >>> (32 - (k & 31 | 0) | 0) | 0) & x | 0) << (32 - (k & 31 | 0) | 0) | 0) | 0 | 0;
+  var $$2 = 0, $$3 = 0, $$4 = 0, $$5 = 0, $$6 = 0, $$7 = 0, $$8 = 0, $$9 = 0, $$10 = 0, $$11 = 0, $$12 = 0, $$13 = 0, $$14 = 0, $$15 = 0, $$16 = 0, $$17 = 0, $$18 = 0, $$19 = 0, $$20 = 0;
+  $$2 = k;
+  $$3 = $$2 & 31 | 0;
+  $$4 = 4294967295 << $$3 | 0;
+  $$5 = x;
+  $$6 = $$4 & $$5 | 0;
+  $$7 = k;
+  $$8 = $$7 & 31 | 0;
+  $$9 = $$6 >>> $$8 | 0;
+  $$10 = k;
+  $$11 = $$10 & 31 | 0;
+  $$12 = 32 - $$11 | 0;
+  $$13 = 4294967295 >>> $$12 | 0;
+  $$14 = x;
+  $$15 = $$13 & $$14 | 0;
+  $$16 = k;
+  $$17 = $$16 & 31 | 0;
+  $$18 = 32 - $$17 | 0;
+  $$19 = $$15 << $$18 | 0;
+  $$20 = $$9 | $$19 | 0;
+  return $$20 | 0;
  }
  
  return {