Mark the module as closed-world when possible to allow DAE optimizations

CountBleck · CountBleck · commit 41a697f1bb5b · 2025-06-02T19:12:46.000-07:00
Due to WebAssembly/binaryen#7135, any function reference is treated as potentially leaked to the outside world, unless the module is marked as closed-world. This prevents DAE from taking place. To fix this, mark the module as closed-world when tables are neither imported nor exported and when exports do not return/contain funcrefs.
diff --git a/src/compiler.ts b/src/compiler.ts
@@ -536,6 +536,12 @@ export class Compiler extends DiagnosticEmitter {
     // initialize lookup maps, built-ins, imports, exports, etc.
     this.program.initialize();
 
+
+    // Binaryen treats all function references as being leaked to the outside world when
+    // the module isn't marked as closed-world (see WebAssembly/binaryen#7135). Therefore,
+    // we should mark the module as closed-world when we're definitely sure it is.
+    module.setClosedWorld(true);
+
     // obtain the main start function
     let startFunctionInstance = this.currentFlow.targetFunction;
     assert(startFunctionInstance.internalName == BuiltinNames.start);
@@ -857,6 +863,7 @@ export class Compiler extends DiagnosticEmitter {
         ImportNames.DefaultNamespace,
         ImportNames.Table
       );
+      module.setClosedWorld(false);
       if (options.pedantic && options.willOptimize) {
         this.pedantic(
           DiagnosticCode.Importing_the_table_disables_some_indirect_call_optimizations,
@@ -866,6 +873,7 @@ export class Compiler extends DiagnosticEmitter {
     }
     if (options.exportTable) {
       module.addTableExport(CommonNames.DefaultTable, ExportNames.Table);
+      module.setClosedWorld(false);
       if (options.pedantic && options.willOptimize) {
         this.pedantic(
           DiagnosticCode.Exporting_the_table_disables_some_indirect_call_optimizations,
@@ -977,6 +985,7 @@ export class Compiler extends DiagnosticEmitter {
                   }
                 }
               }
+              if (functionInstance.signature.returnType.kind == TypeKind.Func) this.module.setClosedWorld(false);
             }
             return;
           }
@@ -1007,6 +1016,7 @@ export class Compiler extends DiagnosticEmitter {
                 this.desiresExportRuntime = true;
               }
             }
+            if (global.type.kind == TypeKind.Func) this.module.setClosedWorld(false);
           }
           if (global.type == Type.v128) {
             this.warning(
diff --git a/src/module.ts b/src/module.ts
@@ -2471,6 +2471,14 @@ export class Module {
     binaryen._BinaryenSetDebugInfo(on);
   }
 
+  getClosedWorld(): bool {
+    return binaryen._BinaryenGetClosedWorld();
+  }
+
+  setClosedWorld(on: bool): void {
+    binaryen._BinaryenSetClosedWorld(on);
+  }
+
   getLowMemoryUnused(): bool {
     return binaryen._BinaryenGetLowMemoryUnused();
   }
diff --git a/tests/compiler/call-optional.release.wat b/tests/compiler/call-optional.release.wat
@@ -31,8 +31,8 @@
    i32.const -2
    local.set $2
   end
-  local.get $0
   local.get $1
+  i32.const 3
   i32.add
   local.get $2
   i32.add
diff --git a/tests/compiler/call-rest.release.wat b/tests/compiler/call-rest.release.wat
@@ -1,9 +1,9 @@
 (module
  (type $0 (func (param i32 i32 i32) (result i32)))
- (type $1 (func))
- (type $2 (func (param i32)))
- (type $3 (func (param i32 i32)))
- (type $4 (func (param i32 i32) (result i32)))
+ (type $1 (func (param i32 i32) (result i32)))
+ (type $2 (func))
+ (type $3 (func (param i32)))
+ (type $4 (func (param i32 i32)))
  (type $5 (func (param i32) (result i32)))
  (type $6 (func (param i32 i32 i32 i32)))
  (type $7 (func (param i32 i32 i64)))
@@ -1874,7 +1874,8 @@
   global.set $~lib/memory/__stack_pointer
   local.get $0
  )
- (func $call-rest/fn (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
+ (func $call-rest/fn (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
   (local $3 i32)
   global.get $~lib/memory/__stack_pointer
   i32.const 4
@@ -1895,43 +1896,41 @@
   i32.const 0
   i32.store
   local.get $0
-  local.get $1
+  i32.const 1
   i32.add
-  local.set $1
-  i32.const 0
   local.set $0
   global.get $~lib/memory/__stack_pointer
-  local.get $2
+  local.get $1
   i32.store
-  local.get $2
+  local.get $1
   call $~lib/array/Array<i32>#get:length
   local.set $3
   loop $for-loop|0
-   local.get $0
+   local.get $2
    local.get $3
    i32.lt_s
    if
     global.get $~lib/memory/__stack_pointer
-    local.get $2
+    local.get $1
     i32.store
+    local.get $1
     local.get $2
-    local.get $0
     call $~lib/array/Array<i32>#__get
-    local.get $1
-    i32.add
-    local.set $1
     local.get $0
-    i32.const 1
     i32.add
     local.set $0
+    local.get $2
+    i32.const 1
+    i32.add
+    local.set $2
     br $for-loop|0
    end
   end
   global.get $~lib/memory/__stack_pointer
   i32.const 4
   i32.add
   global.set $~lib/memory/__stack_pointer
-  local.get $1
+  local.get $0
  )
  (func $call-rest/fn@varargs (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
   global.get $~lib/memory/__stack_pointer
@@ -1977,7 +1976,6 @@
   global.get $~lib/memory/__stack_pointer
   local.get $2
   i32.store offset=4
-  local.get $0
   local.get $1
   local.get $2
   call $call-rest/fn
@@ -2587,7 +2585,6 @@
    global.get $~lib/memory/__stack_pointer
    local.get $0
    i32.store
-   i32.const 1
    i32.const 2
    local.get $0
    call $call-rest/fn
@@ -2609,7 +2606,6 @@
    global.get $~lib/memory/__stack_pointer
    local.get $0
    i32.store
-   i32.const 1
    i32.const 2
    local.get $0
    call $call-rest/fn
diff --git a/tests/compiler/function-call.release.wat b/tests/compiler/function-call.release.wat
@@ -65,7 +65,7 @@
   i32.add
  )
  (func $start:function-call~fn2|4 (param $0 i32) (result i32)
-  local.get $0
+  i32.const 1
  )
  (func $~lib/rt/itcms/visitRoots
   (local $0 i32)
@@ -1412,9 +1412,7 @@
   nop
  )
  (func $function-call/Foo#fnRet (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
-  local.get $1
-  local.get $2
-  i32.add
+  i32.const 3
  )
  (func $~lib/rt/__visit_members (param $0 i32)
   block $folding-inner0
@@ -1533,16 +1531,7 @@
    i32.const 1248
    i32.load
    call_indirect (type $1)
-   i32.const 1
-   i32.ne
-   if
-    i32.const 0
-    i32.const 1152
-    i32.const 20
-    i32.const 1
-    call $~lib/builtins/abort
-    unreachable
-   end
+   drop
    memory.size
    i32.const 16
    i32.shl
@@ -1641,16 +1630,7 @@
    i32.const 1712
    i32.load
    call_indirect (type $1)
-   i32.const 1
-   i32.ne
-   if
-    i32.const 0
-    i32.const 1152
-    i32.const 33
-    i32.const 1
-    call $~lib/builtins/abort
-    unreachable
-   end
+   drop
    global.get $~lib/memory/__stack_pointer
    global.get $function-call/foo
    local.tee $0
diff --git a/tests/compiler/function-expression.release.wat b/tests/compiler/function-expression.release.wat
@@ -86,12 +86,10 @@
   i32.const 1
  )
  (func $start:function-expression~anonymous|4 (param $0 i32) (param $1 i32) (result i32)
-  local.get $0
-  local.get $1
-  i32.add
+  i32.const 3
  )
  (func $start:function-expression~anonymous|5 (param $0 i32) (param $1 i32) (result i32)
-  local.get $0
+  i32.const 1
  )
  (func $start:function-expression~anonymous|6 (param $0 i32) (param $1 i32) (result i32)
   i32.const 42
diff --git a/tests/compiler/function-types.release.wat b/tests/compiler/function-types.release.wat
@@ -28,14 +28,10 @@
   i32.add
  )
  (func $function-types/makeAdder<i64>~anonymous|0 (param $0 i64) (param $1 i64) (result i64)
-  local.get $0
-  local.get $1
-  i64.add
+  i64.const 30
  )
  (func $function-types/makeAdder<f64>~anonymous|0 (param $0 f64) (param $1 f64) (result f64)
-  local.get $0
-  local.get $1
-  f64.add
+  f64.const 4
  )
  (func $~start
   (local $0 i32)
diff --git a/tests/compiler/inlining.release.wat b/tests/compiler/inlining.release.wat
@@ -49,7 +49,7 @@
   i32.const 3
  )
  (func $inlining/func_fe~anonymous|0 (param $0 i32) (result i32)
-  local.get $0
+  i32.const 2
  )
  (func $~lib/rt/itcms/visitRoots
   (local $0 i32)
@@ -1561,16 +1561,7 @@
    i32.const 1104
    i32.load
    call_indirect (type $2)
-   i32.const 2
-   i32.ne
-   if
-    i32.const 0
-    i32.const 1056
-    i32.const 69
-    i32.const 3
-    call $~lib/builtins/abort
-    unreachable
-   end
+   drop
    global.get $~lib/memory/__stack_pointer
    i32.const 123
    i32.store
diff --git a/tests/compiler/resolve-ternary.release.wat b/tests/compiler/resolve-ternary.release.wat
@@ -2418,24 +2418,16 @@
   end
  )
  (func $start:resolve-ternary~anonymous|0 (param $0 i32) (result i32)
-  local.get $0
-  i32.const 1
-  i32.add
+  i32.const 2
  )
  (func $start:resolve-ternary~anonymous|1 (param $0 i32) (result i32)
-  local.get $0
-  i32.const 2
-  i32.add
+  i32.const 3
  )
  (func $resolve-ternary/g1 (param $0 i32) (result i32)
-  local.get $0
-  i32.const 3
-  i32.add
+  i32.const 4
  )
  (func $resolve-ternary/g2 (param $0 i32) (result i32)
-  local.get $0
-  i32.const 4
-  i32.add
+  i32.const 5
  )
  (func $~lib/rt/__visit_members (param $0 i32)
   block $invalid

Original file line number	Diff line number	Diff line change
`@@ -536,6 +536,12 @@ export class Compiler extends DiagnosticEmitter {`
`536`	`536`	`// initialize lookup maps, built-ins, imports, exports, etc.`
`537`	`537`	`this.program.initialize();`
`538`	`538`
	`539`	`+`
	`540`	`+ // Binaryen treats all function references as being leaked to the outside world when`
	`541`	`+ // the module isn't marked as closed-world (see WebAssembly/binaryen#7135). Therefore,`
	`542`	`+ // we should mark the module as closed-world when we're definitely sure it is.`
	`543`	`+ module.setClosedWorld(true);`
	`544`	`+`
`539`	`545`	`// obtain the main start function`
`540`	`546`	`let startFunctionInstance = this.currentFlow.targetFunction;`
`541`	`547`	`assert(startFunctionInstance.internalName == BuiltinNames.start);`
`@@ -857,6 +863,7 @@ export class Compiler extends DiagnosticEmitter {`
`857`	`863`	`ImportNames.DefaultNamespace,`
`858`	`864`	`ImportNames.Table`
`859`	`865`	`);`
	`866`	`+ module.setClosedWorld(false);`
`860`	`867`	`if (options.pedantic && options.willOptimize) {`
`861`	`868`	`this.pedantic(`
`862`	`869`	`DiagnosticCode.Importing_the_table_disables_some_indirect_call_optimizations,`
`@@ -866,6 +873,7 @@ export class Compiler extends DiagnosticEmitter {`
`866`	`873`	`}`
`867`	`874`	`if (options.exportTable) {`
`868`	`875`	`module.addTableExport(CommonNames.DefaultTable, ExportNames.Table);`
	`876`	`+ module.setClosedWorld(false);`
`869`	`877`	`if (options.pedantic && options.willOptimize) {`
`870`	`878`	`this.pedantic(`
`871`	`879`	`DiagnosticCode.Exporting_the_table_disables_some_indirect_call_optimizations,`
`@@ -977,6 +985,7 @@ export class Compiler extends DiagnosticEmitter {`
`977`	`985`	`}`
`978`	`986`	`}`
`979`	`987`	`}`
	`988`	`+ if (functionInstance.signature.returnType.kind == TypeKind.Func) this.module.setClosedWorld(false);`
`980`	`989`	`}`
`981`	`990`	`return;`
`982`	`991`	`}`
`@@ -1007,6 +1016,7 @@ export class Compiler extends DiagnosticEmitter {`
`1007`	`1016`	`this.desiresExportRuntime = true;`
`1008`	`1017`	`}`
`1009`	`1018`	`}`
	`1019`	`+ if (global.type.kind == TypeKind.Func) this.module.setClosedWorld(false);`
`1010`	`1020`	`}`
`1011`	`1021`	`if (global.type == Type.v128) {`
`1012`	`1022`	`this.warning(`
Original file line number	Diff line number	Diff line change
`@@ -2471,6 +2471,14 @@ export class Module {`
`2471`	`2471`	`binaryen._BinaryenSetDebugInfo(on);`
`2472`	`2472`	`}`
`2473`	`2473`
	`2474`	`+ getClosedWorld(): bool {`
	`2475`	`+ return binaryen._BinaryenGetClosedWorld();`
	`2476`	`+ }`
	`2477`	`+`
	`2478`	`+ setClosedWorld(on: bool): void {`
	`2479`	`+ binaryen._BinaryenSetClosedWorld(on);`
	`2480`	`+ }`
	`2481`	`+`
`2474`	`2482`	`getLowMemoryUnused(): bool {`
`2475`	`2483`	`return binaryen._BinaryenGetLowMemoryUnused();`
`2476`	`2484`	`}`
Original file line number	Diff line number	Diff line change
`@@ -86,12 +86,10 @@`
`86`	`86`	`i32.const 1`
`87`	`87`	`)`
`88`	`88`	`(func $start:function-expression~anonymous\|4 (param $0 i32) (param $1 i32) (result i32)`
`89`		`- local.get $0`
`90`		`- local.get $1`
`91`		`- i32.add`
	`89`	`+ i32.const 3`
`92`	`90`	`)`
`93`	`91`	`(func $start:function-expression~anonymous\|5 (param $0 i32) (param $1 i32) (result i32)`
`94`		`- local.get $0`
	`92`	`+ i32.const 1`
`95`	`93`	`)`
`96`	`94`	`(func $start:function-expression~anonymous\|6 (param $0 i32) (param $1 i32) (result i32)`
`97`	`95`	`i32.const 42`
Original file line number	Diff line number	Diff line change
`@@ -28,14 +28,10 @@`
`28`	`28`	`i32.add`
`29`	`29`	`)`
`30`	`30`	`(func $function-types/makeAdder<i64>~anonymous\|0 (param $0 i64) (param $1 i64) (result i64)`
`31`		`- local.get $0`
`32`		`- local.get $1`
`33`		`- i64.add`
	`31`	`+ i64.const 30`
`34`	`32`	`)`
`35`	`33`	`(func $function-types/makeAdder<f64>~anonymous\|0 (param $0 f64) (param $1 f64) (result f64)`
`36`		`- local.get $0`
`37`		`- local.get $1`
`38`		`- f64.add`
	`34`	`+ f64.const 4`
`39`	`35`	`)`
`40`	`36`	`(func $~start`
`41`	`37`	`(local $0 i32)`
Original file line number	Diff line number	Diff line change
`@@ -2418,24 +2418,16 @@`
`2418`	`2418`	`end`
`2419`	`2419`	`)`
`2420`	`2420`	`(func $start:resolve-ternary~anonymous\|0 (param $0 i32) (result i32)`
`2421`		`- local.get $0`
`2422`		`- i32.const 1`
`2423`		`- i32.add`
	`2421`	`+ i32.const 2`
`2424`	`2422`	`)`
`2425`	`2423`	`(func $start:resolve-ternary~anonymous\|1 (param $0 i32) (result i32)`
`2426`		`- local.get $0`
`2427`		`- i32.const 2`
`2428`		`- i32.add`
	`2424`	`+ i32.const 3`
`2429`	`2425`	`)`
`2430`	`2426`	`(func $resolve-ternary/g1 (param $0 i32) (result i32)`
`2431`		`- local.get $0`
`2432`		`- i32.const 3`
`2433`		`- i32.add`
	`2427`	`+ i32.const 4`
`2434`	`2428`	`)`
`2435`	`2429`	`(func $resolve-ternary/g2 (param $0 i32) (result i32)`
`2436`		`- local.get $0`
`2437`		`- i32.const 4`
`2438`		`- i32.add`
	`2430`	`+ i32.const 5`
`2439`	`2431`	`)`
`2440`	`2432`	`(func $~lib/rt/__visit_members (param $0 i32)`
`2441`	`2433`	`block $invalid`