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, 199 insertions, 1 deletions

diff --git a/test/debugInfo.fromasm.imprecise.no-opts b/test/debugInfo.fromasm.imprecise.no-opts
index 06066ff29..4bea2c355 100644
--- a/test/debugInfo.fromasm.imprecise.no-opts
+++ b/test/debugInfo.fromasm.imprecise.no-opts
@@ -4,9 +4,12 @@
  (import "env" "table" (table 0 0 anyfunc))
  (import "env" "memoryBase" (global $memoryBase i32))
  (import "env" "tableBase" (global $tableBase i32))
+ (global $STACKTOP (mut i32) (i32.const 0))
  (export "add" (func $add))
  (export "ret" (func $ret))
  (export "opts" (func $opts))
+ (export "fib" (func $fib))
+ (export "switch_reach" (func $switch_reach))
  (func $add (param $x i32) (param $y i32) (result i32)
   ;; tests/hello_world.c:5
   (set_local $x
@@ -42,7 +45,6 @@
     (i32.const 1)
    )
   )
-  (unreachable)
  )
  (func $opts (param $x i32) (param $y i32) (result i32)
   ;; even-opted.cpp:1
@@ -73,4 +75,200 @@
    )
   )
  )
+ (func $fib (param $$0 i32) (result i32)
+  (local $$$0$lcssa i32)
+  (local $$$01518 i32)
+  (local $$$01518$phi i32)
+  (local $$$01617 i32)
+  (local $$$019 i32)
+  (local $$1 i32)
+  (local $$2 i32)
+  (local $$3 i32)
+  (local $$exitcond i32)
+  (local $label i32)
+  (local $sp i32)
+  (set_local $sp
+   (get_global $STACKTOP)
+  )
+  ;; fib.c:3
+  (set_local $$1
+   (i32.gt_s
+    (get_local $$0)
+    (i32.const 0)
+   )
+  )
+  (if
+   (get_local $$1)
+   (block
+    (set_local $$$01518
+     (i32.const 0)
+    )
+    (set_local $$$01617
+     (i32.const 0)
+    )
+    (set_local $$$019
+     (i32.const 1)
+    )
+   )
+   (block
+    (set_local $$$0$lcssa
+     (i32.const 1)
+    )
+    ;; fib.c:8
+    (return
+     (get_local $$$0$lcssa)
+    )
+   )
+  )
+  (loop $while-in
+   (block $while-out
+    ;; fib.c:4
+    (set_local $$2
+     (i32.add
+      (get_local $$$019)
+      (get_local $$$01518)
+     )
+    )
+    ;; fib.c:3
+    (set_local $$3
+     (i32.add
+      (get_local $$$01617)
+      (i32.const 1)
+     )
+    )
+    ;; fib.c:3
+    (set_local $$exitcond
+     (i32.eq
+      (get_local $$3)
+      (get_local $$0)
+     )
+    )
+    (if
+     (get_local $$exitcond)
+     (block
+      (set_local $$$0$lcssa
+       (get_local $$2)
+      )
+      (br $while-out)
+     )
+     (block
+      (set_local $$$01518$phi
+       (get_local $$$019)
+      )
+      (set_local $$$01617
+       (get_local $$3)
+      )
+      (set_local $$$019
+       (get_local $$2)
+      )
+      (set_local $$$01518
+       (get_local $$$01518$phi)
+      )
+     )
+    )
+    (br $while-in)
+   )
+  )
+  ;; fib.c:8
+  (return
+   (get_local $$$0$lcssa)
+  )
+ )
+ (func $switch_reach (param $$p i32) (result i32)
+  (local $$0 i32)
+  (local $$call i32)
+  (local $$magic i32)
+  (local $$rc$0 i32)
+  (local $$switch$split2D i32)
+  (local $label i32)
+  (local $sp i32)
+  (set_local $sp
+   (get_global $STACKTOP)
+  )
+  (set_local $$magic
+   (i32.add
+    (get_local $$p)
+    (i32.const 52)
+   )
+  )
+  (set_local $$0
+   (get_local $$magic)
+  )
+  (set_local $$switch$split2D
+   (i32.lt_s
+    (get_local $$0)
+    (i32.const 1369188723)
+   )
+  )
+  (if
+   (get_local $$switch$split2D)
+   (block $switch
+    (block $switch-default
+     (block $switch-case
+      (br_table $switch-case $switch-default
+       (i32.sub
+        (get_local $$0)
+        (i32.const -1108210269)
+       )
+      )
+     )
+     (block
+      (set_local $label
+       (i32.const 2)
+      )
+      (br $switch)
+     )
+    )
+    (set_local $$rc$0
+     (i32.const 0)
+    )
+   )
+   (block $switch0
+    (block $switch-default2
+     (block $switch-case1
+      (br_table $switch-case1 $switch-default2
+       (i32.sub
+        (get_local $$0)
+        (i32.const 1369188723)
+       )
+      )
+     )
+     (block
+      (set_local $label
+       (i32.const 2)
+      )
+      (br $switch0)
+     )
+    )
+    (set_local $$rc$0
+     (i32.const 0)
+    )
+   )
+  )
+  (if
+   (i32.eq
+    (get_local $label)
+    (i32.const 2)
+   )
+   (block
+    (set_local $$call
+     (call $switch_reach
+      (get_local $$p)
+     )
+    )
+    (set_local $$rc$0
+     (get_local $$call)
+    )
+   )
+  )
+  (drop
+   (call $switch_reach
+    (get_local $$p)
+   )
+  )
+  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  (return
+   (get_local $$rc$0)
+  )
+ )
 )