[mlir] [sparse] Rename getSparseMatrix to getMatrix

[aartbik]

Summary

Rationale:
More consistent with the other names. Also forward looking to reading
in other kinds of matrices. Also fixes lint issue on hard-coded %llu.

[penpornk]

Sounds good! :)

mlir/integration_test/Sparse/CPU/matrix-market-example.mlir

 // RUN: mlir-opt %s \
 // RUN:  -convert-scf-to-std -convert-vector-to-scf \
 // RUN:  -convert-linalg-to-llvm -convert-vector-to-llvm | \
-// RUN: SPARSE_MATRIX0="%mlir_integration_test_dir/data/test.mtx" \
+// RUN: MATRIX0="%mlir_integration_test_dir/data/test.mtx" \
 // RUN: mlir-cpu-runner \
 // RUN:  -e entry -entry-point-result=void  \
 // RUN:  -shared-libs=%mlir_integration_test_dir/libmlir_c_runner_utils%shlibext | \
 // RUN: FileCheck %s
 
 module {
   func @openMatrix(!llvm.ptr<i8>, memref<index>, memref<index>, memref<index>) -> ()
   func @readMatrixItem(memref<index>, memref<index>, memref<f64>) -> ()
   func @closeMatrix() -> ()
-  func @getSparseMatrix(index) -> (!llvm.ptr<i8>)
+  func @getMatrix(index) -> (!llvm.ptr<i8>)
 
   func @entry() {
     %d0  = constant 0.0 : f64
     %c0  = constant 0 : index
     %c1  = constant 1 : index
     %c5  = constant 5 : index
     %m   = alloc() : memref<index>
     %n   = alloc() : memref<index>
     %nnz = alloc() : memref<index>
     %i   = alloc() : memref<index>
     %j   = alloc() : memref<index>
     %d   = alloc() : memref<f64>
 
     //
     // Read the header of a sparse matrix. This yields the
     // size (m x n) and number of nonzero elements (nnz).
     //
-    %file = call @getSparseMatrix(%c0) : (index) -> (!llvm.ptr<i8>)
+    %file = call @getMatrix(%c0) : (index) -> (!llvm.ptr<i8>)
     call @openMatrix(%file, %m, %n, %nnz)
         : (!llvm.ptr<i8>, memref<index>,
                     memref<index>, memref<index>) -> ()
     %M = load %m[]   : memref<index>
     %N = load %n[]   : memref<index>
     %Z = load %nnz[] : memref<index>
 
     //

mlir/lib/ExecutionEngine/SparseUtils.cpp

if (sparseFile == nullptr) {
     fprintf(stderr, "Cannot close unopened matrix\n");
     exit(1);
   }
   fclose(sparseFile);
   sparseFile = nullptr;
   sparseFilename = nullptr;
 }
 
-// Helper method to read sparse matrix filenames from the environment, defined
-// with the naming convention ${SPARSE_MATRIX0}, ${SPARSE_MATRIX1}, etc.
-extern "C" char *getSparseMatrix(uint64_t id) {
+// Helper method to read matrix filenames from the environment, defined
+// with the naming convention ${MATRIX0}, ${MATRIX1}, etc.
+extern "C" char *getMatrix(uint64_t id) {
   char var[80];
-  sprintf(var, "SPARSE_MATRIX%lu", id);
+  sprintf(var, "MATRIX%" PRIu64, id);
   char *env = getenv(var);
   return env;
 }