Emscripten stack simplification (#1870)

This takes advantage of the recent memory simplification in emscripten, where JS static allocation is done at compile time. That means we know the stack's initial location at compile time, and can apply it. This is the binaryen side of that:

* asm2wasm support for asm.js globals with an initial value var X = Y; where Y is not 0 (which is what the stack now is).
* wasm-emscripten-finalize support for a flag --initial-stack-pointer=X, and remove the old code to import the stack's initial location.

16 files changed, 54 insertions, 18 deletions

diff --git a/test/lld/duplicate_imports.wast.out b/test/lld/duplicate_imports.wast.out
index 6d3417b26..58f5846e6 100644
--- a/test/lld/duplicate_imports.wast.out
+++ b/test/lld/duplicate_imports.wast.out
@@ -9,7 +9,6 @@
  (type $legaltype$puts2 (func (param i32 i32) (result i32)))
  (type $legaltype$invoke_ffd (func (param i32 f64 f64) (result f64)))
  (type $legaltype$invoke_ffd2 (func (param i32 f64 f64) (result f64)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "puts" (func $puts1 (param i32) (result i32)))
  (import "env" "puts" (func $legalimport$puts2 (param i32 i32) (result i32)))
  (import "env" "invoke_ffd" (func $legalimport$invoke_ffd (param i32 f64 f64) (result f64)))
@@ -17,7 +16,7 @@
  (memory $0 2)
  (data (i32.const 568) "Hello, world\00")
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66128))
  (global $global$2 i32 (i32.const 581))
  (export "memory" (memory $0))
diff --git a/test/lld/em_asm.wast.out b/test/lld/em_asm.wast.out
index 009dedc55..92b1ea76f 100644
--- a/test/lld/em_asm.wast.out
+++ b/test/lld/em_asm.wast.out
@@ -7,14 +7,13 @@
  (type $FUNCSIG$ii (func (param i32) (result i32)))
  (type $FUNCSIG$iiii (func (param i32 i32 i32) (result i32)))
  (type $FUNCSIG$iii (func (param i32 i32) (result i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "emscripten_asm_const_i" (func $emscripten_asm_const_i (param i32) (result i32)))
  (import "env" "emscripten_asm_const_iii" (func $emscripten_asm_const_iii (param i32 i32 i32) (result i32)))
  (import "env" "emscripten_asm_const_ii" (func $emscripten_asm_const_ii (param i32 i32) (result i32)))
  (memory $0 2)
  (data (i32.const 568) "{ Module.print(\"Hello world\"); }\00{ return $0 + $1; }\00{ Module.print(\"Got \" + $0); }\00")
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66192))
  (global $global$2 i32 (i32.const 652))
  (export "memory" (memory $0))
diff --git a/test/lld/em_asm_table.wast.out b/test/lld/em_asm_table.wast.out
index 35e593dd7..ae3675d40 100644
--- a/test/lld/em_asm_table.wast.out
+++ b/test/lld/em_asm_table.wast.out
@@ -4,12 +4,11 @@
  (type $FUNCSIG$vii (func (param i32 i32)))
  (type $FUNCSIG$iiii (func (param i32 i32 i32) (result i32)))
  (import "env" "memory" (memory $0 8192))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "emscripten_log" (func $fimport$0 (param i32 i32)))
  (import "env" "emscripten_asm_const_iii" (func $emscripten_asm_const_iii (param i32 i32 i32) (result i32)))
  (table $0 159609 funcref)
  (elem (i32.const 1) $fimport$0 $emscripten_asm_const_iii)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 1048))
  (export "__data_end" (global $global$1))
  (export "stackSave" (func $stackSave))
diff --git a/test/lld/hello_world.wast.mem.out b/test/lld/hello_world.wast.mem.out
index 078620bcd..66dafd460 100644
--- a/test/lld/hello_world.wast.mem.out
+++ b/test/lld/hello_world.wast.mem.out
@@ -3,11 +3,10 @@
  (type $1 (func (result i32)))
  (type $2 (func))
  (type $FUNCSIG$ii (func (param i32) (result i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "puts" (func $puts (param i32) (result i32)))
  (memory $0 2)
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66128))
  (global $global$2 i32 (i32.const 581))
  (export "memory" (memory $0))
diff --git a/test/lld/hello_world.wast.out b/test/lld/hello_world.wast.out
index df89a5756..1b1e199cb 100644
--- a/test/lld/hello_world.wast.out
+++ b/test/lld/hello_world.wast.out
@@ -3,12 +3,11 @@
  (type $1 (func (result i32)))
  (type $2 (func))
  (type $FUNCSIG$ii (func (param i32) (result i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "puts" (func $puts (param i32) (result i32)))
  (memory $0 2)
  (data (i32.const 568) "Hello, world\00")
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66128))
  (global $global$2 i32 (i32.const 581))
  (export "memory" (memory $0))
diff --git a/test/lld/init.wast.out b/test/lld/init.wast.out
index b702fb373..dfff8d5eb 100644
--- a/test/lld/init.wast.out
+++ b/test/lld/init.wast.out
@@ -1,11 +1,10 @@
 (module
  (type $0 (func))
  (type $1 (func (result i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (memory $0 2)
  (data (i32.const 568) "\00\00\00\00\00\00\00\00")
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66112))
  (global $global$2 i32 (i32.const 576))
  (export "memory" (memory $0))
diff --git a/test/lld/recursive.wast.out b/test/lld/recursive.wast.out
index 1c1180e1c..e8f32d99c 100644
--- a/test/lld/recursive.wast.out
+++ b/test/lld/recursive.wast.out
@@ -3,12 +3,11 @@
  (type $1 (func (result i32)))
  (type $2 (func))
  (type $FUNCSIG$iii (func (param i32 i32) (result i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "printf" (func $printf (param i32 i32) (result i32)))
  (memory $0 2)
  (data (i32.const 568) "%d:%d\n\00Result: %d\n\00")
  (table $0 1 1 funcref)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66128))
  (global $global$2 i32 (i32.const 587))
  (export "memory" (memory $0))
diff --git a/test/lld/reserved_func_ptr.wast.jscall.out b/test/lld/reserved_func_ptr.wast.jscall.out
index 6242c3b76..bc9b677d6 100644
--- a/test/lld/reserved_func_ptr.wast.jscall.out
+++ b/test/lld/reserved_func_ptr.wast.jscall.out
@@ -18,7 +18,6 @@
  (type $FUNCSIG$v (func))
  (type $FUNCSIG$vii (func (param i32 i32)))
  (type $FUNCSIG$viiii (func (param i32 i32 i32 i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "_Z4atoiPKc" (func $_Z4atoiPKc (param i32) (result i32)))
  (import "env" "jsCall_ddi" (func $jsCall_ddi (param i32 f64 i32) (result f64)))
  (import "env" "jsCall_fffi" (func $jsCall_fffi (param i32 f32 f32 i32) (result f32)))
@@ -29,7 +28,7 @@
  (memory $0 2)
  (table $0 21 21 funcref)
  (elem (i32.const 1) $_Z18address_taken_funciii $_Z19address_taken_func2iii $jsCall_ddi_0 $jsCall_ddi_1 $jsCall_ddi_2 $jsCall_fffi_0 $jsCall_fffi_1 $jsCall_fffi_2 $jsCall_iii_0 $jsCall_iii_1 $jsCall_iii_2 $jsCall_v_0 $jsCall_v_1 $jsCall_v_2 $jsCall_vi_0 $jsCall_vi_1 $jsCall_vi_2 $jsCall_viii_0 $jsCall_viii_1 $jsCall_viii_2)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66112))
  (global $global$2 i32 (i32.const 568))
  (export "memory" (memory $0))
diff --git a/test/lld/reserved_func_ptr.wast.out b/test/lld/reserved_func_ptr.wast.out
index 393178a00..e0d9ea156 100644
--- a/test/lld/reserved_func_ptr.wast.out
+++ b/test/lld/reserved_func_ptr.wast.out
@@ -8,12 +8,11 @@
  (type $6 (func (param i32) (result i32)))
  (type $FUNCSIG$ii (func (param i32) (result i32)))
  (type $FUNCSIG$viii (func (param i32 i32 i32)))
- (import "env" "STACKTOP" (global $stack$init i32))
  (import "env" "_Z4atoiPKc" (func $_Z4atoiPKc (param i32) (result i32)))
  (memory $0 2)
  (table $0 3 3 funcref)
  (elem (i32.const 1) $_Z18address_taken_funciii $_Z19address_taken_func2iii)
- (global $global$0 (mut i32) (global.get $stack$init))
+ (global $global$0 (mut i32) (i32.const 16384))
  (global $global$1 i32 (i32.const 66112))
  (global $global$2 i32 (i32.const 568))
  (export "memory" (memory $0))
diff --git a/test/unit.asm.js b/test/unit.asm.js
index 05827ce54..b62c7aefb 100644
--- a/test/unit.asm.js
+++ b/test/unit.asm.js
@@ -30,6 +30,8 @@ function asm(global, env, buffer) {
   var HEAPF32 = new global.Float32Array(buffer);
   var HEAPF64 = new global.Float64Array(buffer);
 
+  var nonZero = 1337;
+
   function big_negative() {
     var temp = 0.0;
     temp = +-2147483648;
@@ -785,6 +787,7 @@ function asm(global, env, buffer) {
     emterpretify_assertions_safeHeap();
     call_emscripten_log();
     mod_detectSign(1.0, 2.31, 9.78);
+    nonZero = nonZero + 1 | 0;
   }
 
   function v() {
diff --git a/test/unit.fromasm b/test/unit.fromasm
index b1a24bf5d..c9e20da52 100644
--- a/test/unit.fromasm
+++ b/test/unit.fromasm
@@ -26,6 +26,7 @@
  (global $Int (mut i32) (i32.const 0))
  (global $Double (mut f64) (f64.const 0))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $big_negative))
@@ -1162,6 +1163,12 @@
     )
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $vi (; 55 ;) (; has Stack IR ;) (param $0 i32)
   (nop)
diff --git a/test/unit.fromasm.clamp b/test/unit.fromasm.clamp
index 58cf67a0d..deec92f97 100644
--- a/test/unit.fromasm.clamp
+++ b/test/unit.fromasm.clamp
@@ -24,6 +24,7 @@
  (global $Int (mut i32) (i32.const 0))
  (global $Double (mut f64) (f64.const 0))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $big_negative))
@@ -1238,6 +1239,12 @@
     )
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $vi (; 57 ;) (; has Stack IR ;) (param $0 i32)
   (nop)
diff --git a/test/unit.fromasm.clamp.no-opts b/test/unit.fromasm.clamp.no-opts
index 7a30149ba..95cb543e2 100644
--- a/test/unit.fromasm.clamp.no-opts
+++ b/test/unit.fromasm.clamp.no-opts
@@ -31,6 +31,7 @@
  (global $tempDoublePtr (mut i32) (global.get $tempDoublePtr$asm2wasm$import))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
  (global $STACKTOP (mut i32) (global.get $STACKTOP$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $exportMe))
@@ -2215,6 +2216,12 @@
     (f64.const 9.78)
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $v (; 83 ;)
   (nop)
diff --git a/test/unit.fromasm.imprecise b/test/unit.fromasm.imprecise
index 869873ec1..7ff7a4c18 100644
--- a/test/unit.fromasm.imprecise
+++ b/test/unit.fromasm.imprecise
@@ -22,6 +22,7 @@
  (global $Int (mut i32) (i32.const 0))
  (global $Double (mut f64) (f64.const 0))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $big_negative))
@@ -1141,6 +1142,12 @@
     (f64.const 1)
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $vi (; 54 ;) (; has Stack IR ;) (param $0 i32)
   (nop)
diff --git a/test/unit.fromasm.imprecise.no-opts b/test/unit.fromasm.imprecise.no-opts
index 74dd7efee..69d1ff2ff 100644
--- a/test/unit.fromasm.imprecise.no-opts
+++ b/test/unit.fromasm.imprecise.no-opts
@@ -31,6 +31,7 @@
  (global $tempDoublePtr (mut i32) (global.get $tempDoublePtr$asm2wasm$import))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
  (global $STACKTOP (mut i32) (global.get $STACKTOP$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $exportMe))
@@ -2100,6 +2101,12 @@
     (f64.const 9.78)
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $v (; 78 ;)
   (nop)
diff --git a/test/unit.fromasm.no-opts b/test/unit.fromasm.no-opts
index 561062f04..fb82b572f 100644
--- a/test/unit.fromasm.no-opts
+++ b/test/unit.fromasm.no-opts
@@ -33,6 +33,7 @@
  (global $tempDoublePtr (mut i32) (global.get $tempDoublePtr$asm2wasm$import))
  (global $n (mut i32) (global.get $n$asm2wasm$import))
  (global $STACKTOP (mut i32) (global.get $STACKTOP$asm2wasm$import))
+ (global $nonZero (mut i32) (i32.const 1337))
  (global $exportedNumber i32 (i32.const 42))
  (export "big_negative" (func $big_negative))
  (export "pick" (func $exportMe))
@@ -2141,6 +2142,12 @@
     (f64.const 9.78)
    )
   )
+  (global.set $nonZero
+   (i32.add
+    (global.get $nonZero)
+    (i32.const 1)
+   )
+  )
  )
  (func $v (; 81 ;)
   (nop)