[clang] [CIR] Upstream basic alloca and load support (PR #128792)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -0,0 +1,82 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Decl nodes as CIR code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CIRGenFunction.h"
+#include "clang/AST/Expr.h"
+#include "clang/CIR/MissingFeatures.h"
+
+using namespace clang;
+using namespace clang::CIRGen;
+
+/// Emit code and set up symbol table for a variable declaration with auto,
+/// register, or no storage class specifier. These turn into simple stack
+/// objects, globals depending on target.
+void CIRGenFunction::emitAutoVarDecl(const VarDecl &d) {
+  QualType ty = d.getType();
+  assert(ty.getAddressSpace() == LangAS::Default);
+
+  auto loc = getLoc(d.getSourceRange());
+
+  if (d.isEscapingByref())
+    cgm.errorNYI(d.getSourceRange(),
+                 "emitAutoVarDecl: decl escaping by reference");
+
+  CharUnits alignment = getContext().getDeclAlign(&d);
+
+  // If the type is variably-modified, emit all the VLA sizes for it.
+  if (ty->isVariablyModifiedType())
+    cgm.errorNYI(d.getSourceRange(), "emitAutoVarDecl: variably modified type");
+
+  Address address = Address::invalid();
+  if (!ty->isConstantSizeType())
+    cgm.errorNYI(d.getSourceRange(), "emitAutoVarDecl: non-constant size type");
+
+  // A normal fixed sized variable becomes an alloca in the entry block,
+  mlir::Type allocaTy = convertTypeForMem(ty);
+  // Create the temp alloca and declare variable using it.
+  mlir::Value addrVal;
+  address = createTempAlloca(allocaTy, alignment, loc, d.getName(),
+                             /*ArraySize=*/nullptr);
+  setAddrOfLocalVar(&d, address);
+  // TODO: emit var init and cleanup
----------------
bcardosolopes wrote:

This needs a assert on missing features otherwise it gets hard to track

https://github.com/llvm/llvm-project/pull/128792