--- a/js/src/jit/VMFunctions.h
+++ b/js/src/jit/VMFunctions.h
@@ -257,28 +257,32 @@ struct VMFunction
         outParam(o.outParam),
         returnType(o.returnType),
         argumentRootTypes(o.argumentRootTypes),
         outParamRootType(o.outParamRootType),
         extraValuesToPop(o.extraValuesToPop),
         expectTailCall(o.expectTailCall)
     {
         // Check for valid failure/return type.
-        MOZ_ASSERT_IF(outParam != Type_Void, returnType == Type_Bool);
-        MOZ_ASSERT(returnType == Type_Bool ||
+        MOZ_ASSERT_IF(outParam != Type_Void,
+                      returnType == Type_Void ||
+                      returnType == Type_Bool);
+        MOZ_ASSERT(returnType == Type_Void ||
+                   returnType == Type_Bool ||
                    returnType == Type_Object);
         addToFunctions();
     }
 
   private:
     // Add this to the global list of VMFunctions.
     void addToFunctions();
 };
 
 template <class> struct TypeToDataType { /* Unexpected return type for a VMFunction. */ };
+template <> struct TypeToDataType<void> { static const DataType result = Type_Void; };
 template <> struct TypeToDataType<bool> { static const DataType result = Type_Bool; };
 template <> struct TypeToDataType<JSObject*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<JSFunction*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<NativeObject*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<PlainObject*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<InlineTypedObject*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<NamedLambdaObject*> { static const DataType result = Type_Object; };
 template <> struct TypeToDataType<LexicalEnvironmentObject*> { static const DataType result = Type_Object; };

--- a/js/src/jit/arm/Trampoline-arm.cpp
+++ b/js/src/jit/arm/Trampoline-arm.cpp
@@ -890,16 +890,18 @@ JitRuntime::generateVMWrapper(JSContext*
     // Test for failure.
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, r0, r0, masm.failureLabel());
         break;
       case Type_Bool:
         masm.branchIfFalseBool(r0, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {
       case Type_Handle:
         masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand);

--- a/js/src/jit/arm64/Trampoline-arm64.cpp
+++ b/js/src/jit/arm64/Trampoline-arm64.cpp
@@ -689,16 +689,18 @@ JitRuntime::generateVMWrapper(JSContext*
     // Test for failure.
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, r0, r0, masm.failureLabel());
         break;
       case Type_Bool:
         masm.branchIfFalseBool(r0, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {
       case Type_Value:
         masm.Ldr(ARMRegister(JSReturnReg, 64), MemOperand(masm.GetStackPointer64()));

--- a/js/src/jit/mips32/Trampoline-mips32.cpp
+++ b/js/src/jit/mips32/Trampoline-mips32.cpp
@@ -856,16 +856,18 @@ JitRuntime::generateVMWrapper(JSContext*
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, v0, v0, masm.failureLabel());
         break;
       case Type_Bool:
         // Called functions return bools, which are 0/false and non-zero/true
         masm.branchIfFalseBool(v0, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     masm.freeStack(outParamOffset);
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {

--- a/js/src/jit/mips64/Trampoline-mips64.cpp
+++ b/js/src/jit/mips64/Trampoline-mips64.cpp
@@ -802,16 +802,18 @@ JitRuntime::generateVMWrapper(JSContext*
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, v0, v0, masm.failureLabel());
         break;
       case Type_Bool:
         // Called functions return bools, which are 0/false and non-zero/true
         masm.branchIfFalseBool(v0, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {
       case Type_Handle:
         masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand);

--- a/js/src/jit/x64/Trampoline-x64.cpp
+++ b/js/src/jit/x64/Trampoline-x64.cpp
@@ -774,16 +774,18 @@ JitRuntime::generateVMWrapper(JSContext*
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, rax, rax, masm.failureLabel());
         break;
       case Type_Bool:
         masm.testb(rax, rax);
         masm.j(Assembler::Zero, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {
       case Type_Handle:
         masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand);

--- a/js/src/jit/x86/Trampoline-x86.cpp
+++ b/js/src/jit/x86/Trampoline-x86.cpp
@@ -804,16 +804,18 @@ JitRuntime::generateVMWrapper(JSContext*
     switch (f.failType()) {
       case Type_Object:
         masm.branchTestPtr(Assembler::Zero, eax, eax, masm.failureLabel());
         break;
       case Type_Bool:
         masm.testb(eax, eax);
         masm.j(Assembler::Zero, masm.failureLabel());
         break;
+      case Type_Void:
+        break;
       default:
         MOZ_CRASH("unknown failure kind");
     }
 
     // Load the outparam and free any allocated stack.
     switch (f.outParam) {
       case Type_Handle:
         masm.popRooted(f.outParamRootType, ReturnReg, JSReturnOperand);