Indirect calls on null now either trap with unreachable or, if exception-handlig is enabled, throws a Wasm exception

Author: jayphelps

.github/workflows/ci.yml

@@ -70,9 +70,9 @@ jobs:
       run: npm run clean
     - name: Test experimental features
       env:
-        ASC_FEATURES: mutable-globals,threads,reference-types,bigint-integration
+        ASC_FEATURES: mutable-globals,threads,reference-types,bigint-integration,exception-handling
       run: |
-        npm run test:compiler rt/flags features/js-bigint-integration features/reference-types features/threads
+        npm run test:compiler rt/flags features/js-bigint-integration features/reference-types features/threads features/exception-handling
   test-runtime:
     name: "Test runtimes on node: node"
     runs-on: ubuntu-latest

examples/game-of-life/build/untouched.wat

@@ -60,7 +60,7 @@
        global.get $assembly/config/BGR_DEAD
        i32.const 16777215
        i32.and
-      else       
+      else
        global.get $assembly/config/BGR_ALIVE
        i32.const -16777216
        i32.or
@@ -134,7 +134,7 @@
     i32.eq
     if (result i32)
      local.get $0
-    else     
+    else
      local.get $2
      i32.const 1
      i32.sub
@@ -145,7 +145,7 @@
     i32.eq
     if (result i32)
      i32.const 0
-    else     
+    else
      local.get $2
      i32.const 1
      i32.add
@@ -165,7 +165,7 @@
       i32.eq
       if (result i32)
        local.get $1
-      else       
+      else
        local.get $5
        i32.const 1
        i32.sub
@@ -176,7 +176,7 @@
       i32.eq
       if (result i32)
        i32.const 0
-      else       
+      else
        local.get $5
        i32.const 1
        i32.add
@@ -367,7 +367,7 @@
         i32.shl
         local.get $14
         i32.store
-       else        
+       else
         local.get $5
         local.set $16
         local.get $2
@@ -388,7 +388,7 @@
         local.get $14
         i32.store
        end
-      else       
+      else
        local.get $9
        i32.const 3
        i32.eq
@@ -412,7 +412,7 @@
         i32.shl
         local.get $8
         i32.store
-       else        
+       else
         local.get $5
         local.set $15
         local.get $2
@@ -563,5 +563,6 @@
   end
  )
  (func $null (; 4 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )

examples/mandelbrot/build/untouched.wat

@@ -251,5 +251,6 @@
   end
  )
  (func $null (; 3 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )

examples/n-body/build/untouched.wat

@@ -2225,5 +2225,6 @@
   global.set $~lib/rt/stub/offset
  )
  (func $null (; 24 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )

examples/pson/build/untouched.wat

@@ -484,5 +484,6 @@
   end
  )
  (func $null (; 18 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )

lib/i64/build/untouched.wat

@@ -749,5 +749,6 @@
   global.set $assembly/i64/hi
  )
  (func $null (; 31 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )

src/compiler.ts

@@ -408,6 +408,11 @@ export class Compiler extends DiagnosticEmitter {
     module.removeGlobal(BuiltinSymbols.rtti_base);
     if (this.runtimeFeatures & RuntimeFeatures.RTTI) compileRTTI(this);
 
+    // set up function table
+    var functionTable = this.functionTable;
+    module.setFunctionTable(functionTable.length, 0xffffffff, functionTable, module.i32(0));
+    this.addNullPointerExceptionHandling(module);
+
     // update the heap base pointer
     var memoryOffset = this.memoryOffset;
     memoryOffset = i64_align(memoryOffset, options.usizeType.byteSize);
@@ -447,11 +452,6 @@ 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
-    var functionTable = this.functionTable;
-    module.setFunctionTable(functionTable.length, 0xffffffff, functionTable, module.i32(0));
-    module.addFunction("null", this.ensureFunctionType(null, Type.void), null, module.block(null, []));
-
     // import table if requested (default table is named '0' by Binaryen)
     if (options.importTable) module.addTableImport("0", "env", "table");
 
@@ -462,6 +462,36 @@ export class Compiler extends DiagnosticEmitter {
     return module;
   }
 
+  addNullPointerExceptionHandling(module: Module) {
+    if (this.options.hasFeature(Feature.EXCEPTION_HANDLING)) {
+      let message = this.ensureStaticString("null is not a function");
+      let exceptionType = module.addFunctionType(
+        "NullPointerException",
+        NativeType.None,
+        [NativeType.I32]
+      );
+
+      module.addEvent("NullPointerException", 0, exceptionType);
+      module.addFunction(
+        "null",
+        this.ensureFunctionType(null, Type.void),
+        null,
+        module.block(null, [
+          module.throw("NullPointerException", [message])
+        ])
+      );
+    } else {
+      module.addFunction(
+        "null",
+        this.ensureFunctionType(null, Type.void),
+        null,
+        module.block(null, [
+          module.unreachable()
+        ])
+      );
+    }
+  }
+
   // === Exports ==================================================================================
 
   /** Applies the respective module exports for the specified file. */

tests/allocators/buddy/untouched.wat

@@ -88,7 +88,7 @@
      local.get $1
      i32.const 3
      i32.and
-    else     
+    else
      i32.const 0
     end
     if
@@ -1293,7 +1293,7 @@
    i32.le_u
    if (result i32)
     i32.const 1
-   else    
+   else
     local.get $5
     local.get $3
     i32.add
@@ -1413,7 +1413,7 @@
       end
      end
     end
-   else    
+   else
     local.get $4
     i32.const 7
     i32.and
@@ -1554,7 +1554,7 @@
       local.get $4
       i32.load8_u
       i32.eq
-     else      
+     else
       i32.const 0
      end
      if
@@ -1581,7 +1581,7 @@
     local.get $4
     i32.load8_u
     i32.sub
-   else    
+   else
     i32.const 0
    end
   end
@@ -2019,7 +2019,7 @@
       i32.ne
       if (result i32)
        i32.const 1
-      else       
+      else
        local.get $2
        i32.const 0
        i32.eq
@@ -2060,7 +2060,7 @@
       i32.div_u
       global.get $assembly/buddy/List.SIZE
       i32.add
-     else      
+     else
       local.get $3
      end
      local.set $4
@@ -2164,7 +2164,7 @@
      call $assembly/buddy/parent_is_split
      if (result i32)
       i32.const 1
-     else      
+     else
       local.get $1
       global.get $assembly/buddy/bucket_limit
       i32.eq
@@ -2207,5 +2207,6 @@
   call $start:assembly/index
  )
  (func $null (; 26 ;) (type $FUNCSIG$v)
+  unreachable
  )
 )