RFR: 8178480: Wrong exception being thrown on an invalid MethodType

[Paul Sandoz]

Tricky!

Would you mind making the comment a little more descriptive? e.g.

// Obtain the invoker MethodType outside of the following try block.
// This ensures that an IllegalArgumentException is directly thrown if the
// type would have 256 or more parameters

(IAE can be confused with Access or Argument)

Paul.

> On 11 Apr 2017, at 12:42, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> JDK-8178387 subtly and inadvertently changed what exception was being thrown by LambdaForm.compileToBytecode in
> certain cases - this patch reverts this simplification and adds a comment to warn against future attempts to
> simplify too much..
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8178480
> 
> diff -r 9363dd4a4fb9 src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java
> --- a/src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java Tue Apr 11 18:57:46 2017 +0200
> +++ b/src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java Tue Apr 11 21:35:59 2017 +0200
> @@ -673,9 +673,7 @@
>     /**
>      * Generate customized bytecode for a given LambdaForm.
>      */
> -    static MemberName generateCustomizedCode(LambdaForm form) {
> -        final MethodType invokerType = form.methodType();
> -
> +    static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
>         MemberName pregenerated = lookupPregenerated(form, invokerType);
>         if (pregenerated != null)  return pregenerated; // pre-generated bytecode
> 
> diff -r 9363dd4a4fb9 src/java.base/share/classes/java/lang/invoke/LambdaForm.java
> --- a/src/java.base/share/classes/java/lang/invoke/LambdaForm.java Tue Apr 11 18:57:46 2017 +0200
> +++ b/src/java.base/share/classes/java/lang/invoke/LambdaForm.java Tue Apr 11 21:35:59 2017 +0200
> @@ -847,9 +847,10 @@
>         if (vmentry != null && isCompiled) {
>             return;  // already compiled somehow
>         }
> -        assert(vmentry == null || vmentry.getMethodType().basicType().equals(methodType()));
> +        MethodType invokerType = methodType(); // forces IAE to happen outside try-catch block
> +        assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
>         try {
> -            vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this);
> +            vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
>             if (TRACE_INTERPRETER)
>                 traceInterpreter("compileToBytecode", this);
>             isCompiled = true;
> 
> 
> Thanks!
> 
> /Claes