1D Matrix Multiplication example for HAT

[jjfumero]

Add new example for 1D Matrix Multiplication in HAT.

How to test?

## Compile 
java --add-modules jdk.incubator.code --enable-preview --source 24 bld

## Run with the OpenCL Backend
java @bldr/args hatrun java matmul 

## Run with the CUDA Backend
java @bldr/args hatrun ptx matmul 

Note that the generated kernel for OpenCL contains a race condition:

__kernel void matrixMultiplyKernel(
    __global KernelContext_t *kc, __global F32Array_t* matrixA, __global F32Array_t* matrixB, __global F32Array_t* matrixC, int size
){
    kc->x=get_global_id(0);                   //  << Shared struct across all threads to store the thread-id 
    if(kc->x<kc->maxX){
        for(int j = 0; j<size; j=j+1){
            float acc = (float)0;
            for(int k = 0; k<size; k=k+1){
                acc=acc+matrixA->array[(long)(kc->x*size+k)]*matrixB->array[(long)(k*size+j)];
            }
            matrixC->array[(long)(kc->x*size+j)]=acc;
        }
    }
    return;
}

After applying a patch provided by Gary Frost to solve the race condition, it works.

Patch:

diff --git a/hat/hat/src/main/java/hat/backend/c99codebuilders/C99HatKernelBuilder.java b/hat/hat/src/main/java/hat/backend/c99codebuilders/C99HatKernelBuilder.java
index ade90914d7e..2719fed31ed 100644
--- a/hat/hat/src/main/java/hat/backend/c99codebuilders/C99HatKernelBuilder.java
+++ b/hat/hat/src/main/java/hat/backend/c99codebuilders/C99HatKernelBuilder.java
@@ -26,7 +26,6 @@
 
 
 import hat.buffer.Buffer;
-import hat.buffer.KernelContext;
 import hat.callgraph.KernelCallGraph;
 import hat.callgraph.KernelEntrypoint;
 import hat.optools.FuncOpWrapper;
@@ -72,9 +71,13 @@ T typedefStructOrUnion(boolean isStruct, String name, Consumer<T> consumer) {
 
 
     public final T scope() {
-        return
-                identifier("kc").rarrow().identifier("x").equals().globalId().semicolon().nl();
-                //.identifier("kc").rarrow().identifier("maxX").equals().globalSize().semicolon().nl();
+
+        identifier("KernelContext_t").space().identifier("mine").semicolon().nl();
+        identifier("KernelContext_t").asterisk().space().identifier("kc").equals().ampersand().identifier("mine").semicolon().nl();
+        identifier("kc").rarrow().identifier("x").equals().globalId().semicolon().nl();
+        identifier("kc").rarrow().identifier("maxX").equals().identifier("global_kc").rarrow().identifier("maxX").semicolon().nl();
+        return self();
+
     }
 
     public abstract T globalPtrPrefix();
@@ -137,7 +140,7 @@ public T kernelEntrypoint(KernelEntrypoint kernelEntrypoint, Object[] args) {
                 }
             }
             parenNlIndented(_ -> {
-                        globalPtrPrefix().space().suffix_t("KernelContext").space().asterisk().identifier("kc");
+                        globalPtrPrefix().space().suffix_t("KernelContext").space().asterisk().identifier("global_kc");
                         list.stream().skip(1).forEach(info ->
                                 comma().space().type(info.javaType).space().varName(info.varOp)
                         );

Note: this PR does not provide this path, only the example and the runner extension to run the matrix multiplication.

---

Progress

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Error

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Checkout this PR locally:
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$ git checkout pull/276

Update a local copy of the PR:
$ git checkout pull/276
$ git pull https://git.openjdk.org/babylon.git pull/276/head

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Checkout this PR locally:
$ git pr checkout 276

View PR using the GUI difftool:
$ git pr show -t 276

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/babylon/pull/276.diff

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[jjfumero]

/signed

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[jjfumero]

Still waiting for the OCA approval.