PTX example

[Thomas Wuerthinger]

Yes, Graal only supports one instance that is used for compiling the methods that are scheduled by HotSpot when running Graal as the default compiler for HotSpot. However, in case Graal is running in "hosted mode", you can have any number of instances, and you can explicitly invoke the compiler with a specific backend as shown in the unit test.

- thomas

On Feb 22, 2013, at 10:59 AM, Christian Thalinger <christian.thalinger at oracle.com> wrote:

> 
> On Feb 22, 2013, at 9:06 AM, "Venkatachalam, Vasanth" <Vasanth.Venkatachalam at amd.com> wrote:
> 
>> Hi Thomas,
>> 
>> Thanks for this update. I will test your example as soon as I can.
>> 
>> Can you explain how to switch the ISA that Graal generates code for? For example, if I wanted to switch from using x86 as the backend(the default) to using SPARC, PTX or my own ISA, what would I have to modify? Is there a command line parameter (to be applied at build or run time) for specifying the target ISA?
> 
> Since Graal only supports one compiler instance right now you have to instantiate the right GraalCompiler.  Something hacky like this:
> 
> diff --git a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotGraalRuntime.java b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotGraalRuntime.java
> --- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotGraalRuntime.java
> +++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotGraalRuntime.java
> @@ -141,7 +159,21 @@
> 
>         HotSpotBackend backend = createBackend();
>         GraalOptions.StackShadowPages = config.stackShadowPages;
> -        compiler = new GraalCompiler(getRuntime(), getTarget(), backend);
> +//        compiler = new GraalCompiler(getRuntime(), getTarget(), backend);
> +        // TODO GraalRuntime needs to support multiple compilers
> +        {
> +            //protected TargetDescription createTarget() {
> +            final int wordSize = 8;
> +            final int stackFrameAlignment = 16;
> +            final int stackBias = 0;
> +            final int implicitNullCheckLimit = 4096;
> +            TargetDescription target = new TargetDescription(new PTX(), true, stackFrameAlignment, stackBias, implicitNullCheckLimit, config.vmPageSize, wordSize, true, true);
> +
> +            //protected HotSpotBackend createBackend() {
> +            Backend ptxbackend = new PTXBackend(getRuntime(), target);
> +
> +            compiler = new GraalCompiler(getRuntime(), target, ptxbackend);
> +        }
>         if (GraalOptions.CacheGraphs) {
>             cache = new HotSpotGraphCache();
>         }
> 
> -- Chris
> 
>> 
>> Vasanth
>> 
>> -----Original Message-----
>> From: Thomas Wuerthinger [mailto:thomas.wuerthinger at oracle.com] 
>> Sent: Thursday, February 21, 2013 5:30 PM
>> To: Venkatachalam, Vasanth
>> Cc: graal-dev at openjdk.java.net; sumatra-dev at openjdk.java.net
>> Subject: PTX example
>> 
>> Vasanth,
>> 
>> I've committed and pushed the basic PTX example. After running "./mx.sh --vm server build" and "./mx.sh --vm server unittest BasicPTXTest" you should get the output I pasted in below. The "--vm server" flag means that you are using Graal in hosted mode running on top of HotSpot's server compiler. You can also start the unit test from within Eclipse after generating Eclipse project files with "./mx.sh ideinit".
>> 
>> Note that the example is still very basic and we'll need more restructuring of the compiler backend to nicely work with GPU architectures. But we have to start with *something* ;).
>> 
>> - thomas
>> 
>> running tests in com.oracle.graal.compiler.ptx.test
>> JUnit version 4.8
>> .0: int
>> .entry test1Snippet (	
>> 	.param .u32 param0
>> ) {	
>> 	  .reg .pred %p;
>> 	  .reg .u32 %r<16>;
>> L87:
>> 	mov.s32 %r0, %r6;
>> 	add.s32 %r0, %r0, 1;
>> 	exit; 
>> }	
>> 
>> result=com.oracle.graal.api.code.CompilationResult at 665df3c6
>> 
>> Time: 0.03
>> 
>> OK (1 test) 
>> 
>