[clang] [CIR] Pointer and vptr width from a CIR-native data-layout entry (PR #204185)

[Akshay K via cfe-commits]

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@@ -42,7 +45,25 @@ static void setMLIRDataLayout(mlir::ModuleOp &mod, const llvm::DataLayout &dl) {
   mlir::MLIRContext *mlirContext = mod.getContext();
   mlir::DataLayoutSpecInterface dlSpec =
       mlir::translateDataLayout(dl, mlirContext);
-  mod->setAttr(mlir::DLTIDialect::kDataLayoutAttrName, dlSpec);
+
+  // Record cir.ptr size/alignment as a #ptr.spec entry keyed on cir.ptr.
+  // TODO(cir): only the default address space is recorded.
+  assert(!cir::MissingFeatures::dataLayoutPtrHandlingBasedOnLangAS());
+  constexpr unsigned kBitsInByte = 8;
+  unsigned ptrSizeBits = dl.getPointerSizeInBits(/*AS=*/0);
+  unsigned ptrAbiBits =
+      dl.getPointerABIAlignment(/*AS=*/0).value() * kBitsInByte;
+  unsigned ptrPrefBits =
+      dl.getPointerPrefAlignment(/*AS=*/0).value() * kBitsInByte;
+  auto ptrKey = cir::PointerType::get(cir::VoidType::get(mlirContext));
+  auto ptrSpec = mlir::ptr::SpecAttr::get(mlirContext, ptrSizeBits, ptrAbiBits,
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kumarak wrote:

Pushed a commit to have CIR native `PtrSpecAttr` mirroring `ptr::SpecAttr` that will hold the `PointerType` specification. Also, move the `setMLIRDatalayout` to use it for both `cir-translate` and `-fclagir` path.

https://github.com/llvm/llvm-project/pull/204185