Preserve debug info through the optimizer (#981)

* add debugInfo option to passes, and use it to keep debug info alive through optimizations when we need it

* add fib testcase for debug info

* when preserving debug info, do not move code around call-imports, so debug info intrinsics remain stationary

* improve wasm-module-building handling of the single-threaded case: don't create workers, which is more efficient and also nicer for debugging

* process debug info in a more precise way, reordering it from being after the node (as it was a comment in JS) to before the node

* remove unreachable hack for debug info, which is no longer needed since we reorder them, and make sure to finalize blocks in which we reorder

1 files changed, 61 insertions, 1 deletions

diff --git a/test/debugInfo.asm.js b/test/debugInfo.asm.js
index 929d79804..29b08575a 100644
--- a/test/debugInfo.asm.js
+++ b/test/debugInfo.asm.js
@@ -1,5 +1,6 @@
 function () {
   "use asm";
+  var STACKTOP = 0;
   function add(x, y) {
     x = x | 0;
     y = y | 0;
@@ -21,6 +22,65 @@ function () {
     x = (x | 0) % (y | 0); //@line 3 "even-opted.cpp"
     return x + y | 0;
   }
-  return { add: add, ret: ret, opts: opts };
+  function fib($0) {
+   $0 = $0|0;
+   var $$0$lcssa = 0, $$01518 = 0, $$01518$phi = 0, $$01617 = 0, $$019 = 0, $1 = 0, $2 = 0, $3 = 0, $exitcond = 0, label = 0, sp = 0;
+   sp = STACKTOP;
+   $1 = ($0|0)>(0); //@line 3 "fib.c"
+   if ($1) {
+    $$01518 = 0;$$01617 = 0;$$019 = 1;
+   } else {
+    $$0$lcssa = 1;
+    return ($$0$lcssa|0); //@line 8 "fib.c"
+   }
+   while(1) {
+    $2 = (($$019) + ($$01518))|0; //@line 4 "fib.c"
+    $3 = (($$01617) + 1)|0; //@line 3 "fib.c"
+    $exitcond = ($3|0)==($0|0); //@line 3 "fib.c"
+    if ($exitcond) {
+     $$0$lcssa = $2;
+     break;
+    } else {
+     $$01518$phi = $$019;$$01617 = $3;$$019 = $2;$$01518 = $$01518$phi;
+    }
+   }
+   return ($$0$lcssa|0); //@line 8 "fib.c"
+  }
+  function switch_reach($p) {
+   $p = $p|0;
+   var $0 = 0, $call = 0, $magic = 0, $rc$0 = 0, $switch$split2D = 0, label = 0, sp = 0;
+   sp = STACKTOP;
+   $magic = ((($p)) + 52|0);
+   $0 = $magic;
+   $switch$split2D = ($0|0)<(1369188723);
+   if ($switch$split2D) {
+    switch ($0|0) {
+    case -1108210269:  {
+     label = 2;
+     break;
+    }
+    default: {
+     $rc$0 = 0;
+    }
+    }
+   } else {
+    switch ($0|0) {
+    case 1369188723:  {
+     label = 2;
+     break;
+    }
+    default: {
+     $rc$0 = 0;
+    }
+    }
+   }
+   if ((label|0) == 2) {
+    $call = switch_reach($p) | 0;
+    $rc$0 = $call;
+   }
+   switch_reach($p) | 0;
+   return ($rc$0|0); //@line 59950 "/tmp/emscripten_test_binaryen2_28hnAe/src.c"
+  }
+  return { add: add, ret: ret, opts: opts, fib: fib, switch_reach: switch_reach };
 }