Remove null function table entry (#1012)

Author: dcodeIO

src/compiler.ts

@@ -303,8 +303,8 @@ export class Compiler extends DiagnosticEmitter {
   memorySegments: MemorySegment[] = [];
   /** Map of already compiled static string segments. */
   stringSegments: Map<string,MemorySegment> = new Map();
-  /** Function table being compiled. */
-  functionTable: string[] = [ "null" ];
+  /** Function table being compiled. First elem is blank. */
+  functionTable: string[] = [];
   /** Argument count helper global. */
   argcVar: GlobalRef = 0;
   /** Argument count helper setter. */
@@ -452,10 +452,9 @@ export class Compiler extends DiagnosticEmitter {
     // import memory if requested (default memory is named '0' by Binaryen)
     if (options.importMemory) module.addMemoryImport("0", "env", "memory", isSharedMemory);
 
-    // set up function table
+    // set up function table (first elem is blank)
     var functionTable = this.functionTable;
-    module.setFunctionTable(functionTable.length, Module.UNLIMITED_TABLE, functionTable, module.i32(0));
-    module.addFunction("null", NativeType.None, NativeType.None, null, module.unreachable());
+    module.setFunctionTable(1 + functionTable.length, Module.UNLIMITED_TABLE, functionTable, module.i32(1));
 
     // import and/or export table if requested (default table is named '0' by Binaryen)
     if (options.importTable) module.addTableImport("0", "env", "table");
@@ -1605,7 +1604,7 @@ export class Compiler extends DiagnosticEmitter {
       return func.functionTableIndex;
     }
     var functionTable = this.functionTable;
-    var index = functionTable.length;
+    var index = 1 + functionTable.length; // first elem is blank
     if (!func.is(CommonFlags.TRAMPOLINE) && func.signature.requiredParameters < func.signature.parameterTypes.length) {
       // insert the trampoline if the function has optional parameters
       func = this.ensureTrampoline(func);

tests/compiler/ReturnType.optimized.wat

@@ -1,8 +1,4 @@
 (module
- (type $none_=>_none (func))
  (memory $0 0)
  (export "memory" (memory $0))
- (func $null (; 0 ;)
-  unreachable
- )
 )

tests/compiler/ReturnType.untouched.wat

@@ -1,10 +1,5 @@
 (module
- (type $none_=>_none (func))
  (memory $0 0)
  (table $0 1 funcref)
- (elem (i32.const 0) $null)
  (export "memory" (memory $0))
- (func $null (; 0 ;)
-  unreachable
- )
 )

tests/compiler/abi.optimized.wat

@@ -19,7 +19,4 @@
   i32.const 0
   global.set $abi/y
  )
- (func $null (; 2 ;)
-  unreachable
- )
 )

tests/compiler/abi.untouched.wat

@@ -6,7 +6,6 @@
  (memory $0 1)
  (data (i32.const 8) "\0c\00\00\00\01\00\00\00\01\00\00\00\0c\00\00\00a\00b\00i\00.\00t\00s\00")
  (table $0 1 funcref)
- (elem (i32.const 0) $null)
  (global $abi/condition (mut i32) (i32.const 0))
  (global $abi/y (mut i32) (i32.const 0))
  (export "memory" (memory $0))
@@ -202,7 +201,4 @@
  (func $start (; 6 ;)
   call $start:abi
  )
- (func $null (; 7 ;)
-  unreachable
- )
 )

tests/compiler/asc-constants.optimized.wat

@@ -1,8 +1,4 @@
 (module
- (type $none_=>_none (func))
  (memory $0 0)
  (export "memory" (memory $0))
- (func $null (; 0 ;)
-  unreachable
- )
 )

tests/compiler/asc-constants.untouched.wat

@@ -2,7 +2,6 @@
  (type $none_=>_none (func))
  (memory $0 0)
  (table $0 1 funcref)
- (elem (i32.const 0) $null)
  (global $~lib/ASC_TARGET i32 (i32.const 0))
  (global $~lib/ASC_NO_ASSERT i32 (i32.const 0))
  (global $~lib/ASC_MEMORY_BASE i32 (i32.const 0))
@@ -52,7 +51,4 @@
  (func $start (; 1 ;)
   call $start:asc-constants
  )
- (func $null (; 2 ;)
-  unreachable
- )
 )

tests/compiler/assert-nonnull.optimized.wat

@@ -1,15 +1,13 @@
 (module
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $none_=>_i32 (func (result i32)))
- (type $none_=>_none (func))
  (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 $0 1)
  (data (i32.const 8) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e")
  (data (i32.const 64) "\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 112) "^\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)
- (elem (i32.const 0) $null)
  (global $~lib/argc (mut i32) (i32.const 0))
  (export "memory" (memory $0))
  (export "testVar" (func $assert-nonnull/testVar))
@@ -192,7 +190,4 @@
    unreachable
   end
  )
- (func $null (; 15 ;)
-  unreachable
- )
 )

tests/compiler/assert-nonnull.untouched.wat

@@ -2,7 +2,6 @@
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $none_=>_i32 (func (result i32)))
  (type $i32_i32_=>_i32 (func (param 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)))
@@ -11,7 +10,6 @@
  (data (i32.const 64) "\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\00")
  (data (i32.const 112) "^\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)
- (elem (i32.const 0) $null)
  (global $~lib/argc (mut i32) (i32.const 0))
  (export "memory" (memory $0))
  (export "testVar" (func $assert-nonnull/testVar))
@@ -376,7 +374,4 @@
   call $~lib/rt/stub/__release
   local.get $2
  )
- (func $null (; 19 ;)
-  unreachable
- )
 )

tests/compiler/assert.optimized.wat

@@ -1,8 +1,4 @@
 (module
- (type $none_=>_none (func))
  (memory $0 0)
  (export "memory" (memory $0))
- (func $null (; 0 ;)
-  unreachable
- )
 )