Expose setArgumentsLength only when required (#1267)

Author: dcodeIO

src/compiler.ts

@@ -294,7 +294,9 @@ export const enum RuntimeFeatures {
   /** Requires the built-in globals visitor. */
   visitGlobals = 1 << 2,
   /** Requires the built-in members visitor. */
-  visitMembers = 1 << 3
+  visitMembers = 1 << 3,
+  /** Requires the setArgumentsLength export. */
+  setArgumentsLength = 1 << 4
 }
 
 /** Exported names of compiler-generated elements. */
@@ -602,6 +604,14 @@ export class Compiler extends DiagnosticEmitter {
       let file = unchecked(_values[i]);
       if (file.source.sourceKind == SourceKind.USER_ENTRY) this.ensureModuleExports(file);
     }
+
+    // expose the arguments length helper if there are varargs exports
+    if (this.runtimeFeatures & RuntimeFeatures.setArgumentsLength) {
+      module.addFunction(BuiltinNames.setArgumentsLength, NativeType.I32, NativeType.None, null,
+        module.global_set(BuiltinNames.argumentsLength, module.local_get(0, NativeType.I32))
+      );
+      module.addFunctionExport(BuiltinNames.setArgumentsLength, ExportNames.setArgumentsLength);
+    }
     return module;
   }
 
@@ -703,6 +713,7 @@ export class Compiler extends DiagnosticEmitter {
             // utilize varargs stub to fill in omitted arguments
             functionInstance = this.ensureVarargsStub(functionInstance);
             this.ensureArgumentsLength();
+            this.runtimeFeatures |= RuntimeFeatures.setArgumentsLength;
           }
           if (functionInstance.is(CommonFlags.COMPILED)) this.module.addFunctionExport(functionInstance.internalName, prefix + name);
         }
@@ -6849,15 +6860,6 @@ export class Compiler extends DiagnosticEmitter {
     if (!this.builtinArgumentsLength) {
       let module = this.module;
       this.builtinArgumentsLength = module.addGlobal(BuiltinNames.argumentsLength, NativeType.I32, true, module.i32(0));
-      // TODO: Enable this once mutable globals are the default nearly everywhere.
-      // if (this.options.hasFeature(Feature.MUTABLE_GLOBALS)) {
-      //   module.addGlobalExport(BuiltinNames.argumentsLength, ExportNames.argumentsLength);
-      // } else {
-        module.addFunction(BuiltinNames.setArgumentsLength, NativeType.I32, NativeType.None, null,
-          module.global_set(BuiltinNames.argumentsLength, module.local_get(0, NativeType.I32))
-        );
-        module.addFunctionExport(BuiltinNames.setArgumentsLength, ExportNames.setArgumentsLength);
-      // }
     }
   }
 

tests/compiler/assert-nonnull.optimized.wat

@@ -1,7 +1,6 @@
 (module
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $none_=>_i32 (func (result i32)))
- (type $i32_=>_none (func (param i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
@@ -10,7 +9,6 @@
  (data (i32.const 1152) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s")
  (data (i32.const 1200) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y")
  (table $0 1 funcref)
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (export "testVar" (func $assert-nonnull/testVar))
  (export "testObj" (func $assert-nonnull/testObj))
@@ -188,9 +186,6 @@
   call $~lib/builtins/abort
   unreachable
  )
- (func $~setArgumentsLength (param $0 i32)
-  nop
- )
  (func $assert-nonnull/testFn (param $0 i32) (result i32)
   local.get $0
   call_indirect (type $none_=>_i32)

tests/compiler/assert-nonnull.untouched.wat

@@ -12,7 +12,6 @@
  (data (i32.const 192) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y\00")
  (table $0 1 funcref)
  (global $~argumentsLength (mut i32) (i32.const 0))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (export "testVar" (func $assert-nonnull/testVar))
  (export "testObj" (func $assert-nonnull/testObj))
@@ -336,10 +335,6 @@
   call $~lib/rt/stub/__release
   local.get $2
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $assert-nonnull/testFn (param $0 i32) (result i32)
   (local $1 i32)
   i32.const 0

tests/compiler/call-inferred.optimized.wat

@@ -1,10 +1,5 @@
 (module
- (type $i32_=>_none (func (param i32)))
  (memory $0 1)
  (data (i32.const 1024) " \00\00\00\01\00\00\00\01\00\00\00 \00\00\00c\00a\00l\00l\00-\00i\00n\00f\00e\00r\00r\00e\00d\00.\00t\00s")
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
- (func $~setArgumentsLength (param $0 i32)
-  nop
- )
 )

tests/compiler/call-inferred.untouched.wat

@@ -1,7 +1,6 @@
 (module
  (type $f32_=>_f32 (func (param f32) (result f32)))
  (type $none_=>_none (func))
- (type $i32_=>_none (func (param i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $f64_=>_f64 (func (param f64) (result f64)))
@@ -10,7 +9,6 @@
  (data (i32.const 16) " \00\00\00\01\00\00\00\01\00\00\00 \00\00\00c\00a\00l\00l\00-\00i\00n\00f\00e\00r\00r\00e\00d\00.\00t\00s\00")
  (table $0 1 funcref)
  (global $~argumentsLength (mut i32) (i32.const 0))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (start $~start)
  (func $call-inferred/foo<i32> (param $0 i32) (result i32)
@@ -40,10 +38,6 @@
   local.get $0
   call $call-inferred/bar<f32>
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $start:call-inferred
   i32.const 42
   call $call-inferred/foo<i32>

tests/compiler/call-optional.optimized.wat

@@ -1,13 +1,11 @@
 (module
  (type $none_=>_none (func))
  (type $i32_i32_i32_=>_i32 (func (param i32 i32 i32) (result i32)))
- (type $i32_=>_none (func (param i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
  (data (i32.const 1024) " \00\00\00\01\00\00\00\01\00\00\00 \00\00\00c\00a\00l\00l\00-\00o\00p\00t\00i\00o\00n\00a\00l\00.\00t\00s")
  (global $~argumentsLength (mut i32) (i32.const 0))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (start $~start)
  (func $call-optional/opt (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
@@ -40,10 +38,6 @@
   local.get $2
   call $call-optional/opt
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $start:call-optional
   i32.const 1
   global.set $~argumentsLength

tests/compiler/call-optional.untouched.wat

@@ -1,7 +1,6 @@
 (module
  (type $i32_i32_i32_=>_i32 (func (param i32 i32 i32) (result i32)))
  (type $none_=>_none (func))
- (type $i32_=>_none (func (param i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
@@ -10,7 +9,6 @@
  (elem (i32.const 1) $call-optional/opt@varargs)
  (global $~argumentsLength (mut i32) (i32.const 0))
  (global $call-optional/optIndirect (mut i32) (i32.const 1))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (start $~start)
  (func $call-optional/opt (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
@@ -43,10 +41,6 @@
   local.get $2
   call $call-optional/opt
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $start:call-optional
   i32.const 3
   i32.const 0

tests/compiler/class-static-function.optimized.wat

@@ -1,10 +1,5 @@
 (module
- (type $i32_=>_none (func (param i32)))
  (memory $0 1)
  (data (i32.const 1024) "0\00\00\00\01\00\00\00\01\00\00\000\00\00\00c\00l\00a\00s\00s\00-\00s\00t\00a\00t\00i\00c\00-\00f\00u\00n\00c\00t\00i\00o\00n\00.\00t\00s")
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
- (func $~setArgumentsLength (param $0 i32)
-  nop
- )
 )

tests/compiler/class-static-function.untouched.wat

@@ -1,7 +1,6 @@
 (module
  (type $none_=>_none (func))
  (type $none_=>_i32 (func (result i32)))
- (type $i32_=>_none (func (param i32)))
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
@@ -10,16 +9,11 @@
  (table $0 2 funcref)
  (elem (i32.const 1) $class-static-function/Example.staticFunc)
  (global $~argumentsLength (mut i32) (i32.const 0))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "memory" (memory $0))
  (start $~start)
  (func $class-static-function/Example.staticFunc (result i32)
   i32.const 42
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $class-static-function/call (param $0 i32) (result i32)
   i32.const 0
   global.set $~argumentsLength

tests/compiler/exports.optimized.wat

@@ -19,7 +19,6 @@
  (global $exports/vehicles.Car i32 (i32.const 4))
  (export "memory" (memory $0))
  (export "add" (func $exports/add))
- (export "__setArgumentsLength" (func $~setArgumentsLength))
  (export "subOpt" (func $exports/subOpt@varargs))
  (export "math.sub" (func $exports/subOpt))
  (export "Animal.CAT" (global $exports/Animal.CAT))
@@ -45,6 +44,7 @@
  (export "vehicles.Car.TIRES" (global $exports/vehicles.Car.TIRES))
  (export "vehicles.Car.getNumTires" (func $exports/Car.getNumTires))
  (export "outer.inner.a" (global $exports/outer.inner.a))
+ (export "__setArgumentsLength" (func $~setArgumentsLength))
  (start $~start)
  (func $exports/add (param $0 i32) (param $1 i32) (result i32)
   local.get $0
@@ -159,10 +159,6 @@
   local.get $1
   i32.sub
  )
- (func $~setArgumentsLength (param $0 i32)
-  local.get $0
-  global.set $~argumentsLength
- )
  (func $exports/Car#constructor@varargs (param $0 i32) (param $1 i32) (result i32)
   block $1of1
    block $0of1
@@ -217,4 +213,8 @@
   i32.store
   local.get $0
  )
+ (func $~setArgumentsLength (param $0 i32)
+  local.get $0
+  global.set $~argumentsLength
+ )
 )