Handles basic syntax using ext_vector_type type. (#179)

* Handles basic syntax using ext_vector_type type.
* Improvement is needed to support more complex syntax (such as ext.xyz)

* Refactors implementation of VisitExtVectorElementExpr using CommonArrayLookup.

* Adds test.

Author: mmoadeli

tools/mlir-clang/Lib/clang-mlir.cc

@@ -453,6 +453,32 @@ mlir::Value MLIRScanner::createAllocOp(mlir::Type t, VarDecl *name,
   return alloc;
 }
 
+ValueCategory
+MLIRScanner::VisitExtVectorElementExpr(clang::ExtVectorElementExpr *expr) {
+  auto base = Visit(expr->getBase());
+  SmallVector<uint32_t, 4> indices;
+  expr->getEncodedElementAccess(indices);
+  assert(indices.size() == 1 &&
+         "The support for higher dimensions to be implemented.");
+  auto idx = castToIndex(getMLIRLocation(expr->getAccessorLoc()),
+                         builder.create<ConstantIntOp>(loc, indices[0], 32));
+  assert(base.isReference);
+  base.isReference = false;
+  auto mt = base.val.getType().cast<MemRefType>();
+  auto shape = std::vector<int64_t>(mt.getShape());
+  if (shape.size() == 1) {
+    shape[0] = -1;
+  } else {
+    shape.erase(shape.begin());
+  }
+  auto mt0 =
+      mlir::MemRefType::get(shape, mt.getElementType(),
+                            MemRefLayoutAttrInterface(), mt.getMemorySpace());
+  base.val = builder.create<polygeist::SubIndexOp>(loc, mt0, base.val,
+                                                   getConstantIndex(0));
+  return CommonArrayLookup(base, idx, base.isReference);
+}
+
 ValueCategory MLIRScanner::VisitConstantExpr(clang::ConstantExpr *expr) {
   auto sv = Visit(expr->getSubExpr());
   if (auto ty = getMLIRType(expr->getType()).dyn_cast<mlir::IntegerType>()) {
@@ -4237,9 +4263,11 @@ MLIRASTConsumer::GetOrCreateGlobal(const ValueDecl *FD, std::string prefix,
   auto rt = getMLIRType(FD->getType());
   unsigned memspace = 0;
   bool isArray = isa<clang::ArrayType>(FD->getType());
+  bool isExtVectorType =
+      isa<clang::ExtVectorType>(FD->getType()->getUnqualifiedDesugaredType());
 
   mlir::MemRefType mr;
-  if (!isArray) {
+  if (!isArray && !isExtVectorType) {
     mr = mlir::MemRefType::get(1, rt, {}, memspace);
   } else {
     auto mt = rt.cast<mlir::MemRefType>();

tools/mlir-clang/Lib/clang-mlir.h

@@ -235,6 +235,8 @@ class MLIRScanner : public StmtVisitor<MLIRScanner, ValueCategory> {
 
   ValueCategory VisitImplicitValueInitExpr(clang::ImplicitValueInitExpr *decl);
 
+  ValueCategory VisitExtVectorElementExpr(clang::ExtVectorElementExpr *expr);
+
   ValueCategory VisitConstantExpr(clang::ConstantExpr *expr);
 
   ValueCategory VisitAtomicExpr(clang::AtomicExpr *expr);

tools/mlir-clang/Test/Verification/ext_vector_type.cpp

@@ -0,0 +1,24 @@
+// RUN: mlir-clang %s --function=* -S | FileCheck %s
+
+typedef size_t size_t_vec __attribute__((ext_vector_type(3)));
+
+size_t evt() {
+  size_t_vec stv;
+  return stv.x;
+}
+
+extern "C" const size_t_vec stv;
+size_t evt2() {
+  return stv.x;
+}
+
+// CHECK:   func.func @_Z3evtv() -> i32 attributes {llvm.linkage = #llvm.linkage<external>} {
+// CHECK-NEXT:    %0 = memref.alloca() : memref<1x3xi32>
+// CHECK-NEXT:    %1 = affine.load %0[0, 0] : memref<1x3xi32>
+// CHECK-NEXT:    return %1 : i32
+// CHECK-NEXT:    }
+// CHECK:   func.func @_Z4evt2v() -> i32 attributes {llvm.linkage = #llvm.linkage<external>} {
+// CHECK-NEXT:     %0 = memref.get_global @stv : memref<3xi32>
+// CHECK-NEXT:     %1 = affine.load %0[0] : memref<3xi32>
+// CHECK-NEXT:     return %1 : i32
+// CHECK-NEXT:     }