[Mlir-commits] [mlir] EmitC: Add emitc.global and emitc.get_global (#145) (PR #88701)

[Simon Camphausen]

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@@ -50,6 +50,68 @@ struct ConvertAlloca final : public OpConversionPattern<memref::AllocaOp> {
   }
 };
 
+struct ConvertGlobal final : public OpConversionPattern<memref::GlobalOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(memref::GlobalOp op, OpAdaptor operands,
+                  ConversionPatternRewriter &rewriter) const override {
+
+    if (!op.getType().hasStaticShape()) {
+      return rewriter.notifyMatchFailure(
+          op.getLoc(), "cannot transform global with dynamic shape");
+    }
+
+    if (op.getAlignment().value_or(1) > 1) {
+      // TODO: Extend GlobalOp to specify alignment via the `alignas` specifier.
+      return rewriter.notifyMatchFailure(
+          op.getLoc(), "global variable with alignment requirement is "
+                       "currently not supported");
+    }
+    auto resultTy = getTypeConverter()->convertType(op.getType());
+    if (!resultTy) {
+      return rewriter.notifyMatchFailure(op.getLoc(),
+                                         "cannot convert result type");
+    }
+
+    SymbolTable::Visibility visibility = SymbolTable::getSymbolVisibility(op);
+    if (visibility != SymbolTable::Visibility::Public &&
+        visibility != SymbolTable::Visibility::Private) {
+      return rewriter.notifyMatchFailure(
+          op.getLoc(),
+          "only public and private visibility is currently supported");
+    }
+    // We are explicit in specifier the linkage because the default linkage
+    // for constants is different in C and C++.
+    bool staticSpecifier = visibility == SymbolTable::Visibility::Private;
+    bool externSpecifier = !staticSpecifier;
+
+    rewriter.replaceOpWithNewOp<emitc::GlobalOp>(
+        op, operands.getSymName(), resultTy, operands.getInitialValueAttr(),
----------------
simon-camp wrote:

We need to explicitly handle uninitialized globals. (By mapping UnitAttr to std::nullopt I think)

https://github.com/llvm/llvm-project/pull/88701