[CIR] Introduce the CIR global_view attribute (#153044)

This change introduces the #cir.global_view attribute and adds support
for using that attribute to handle initializing a global variable with
the address of another global variable.

This does not yet include support for the optional list of indices to
get an offset from the base address. Those will be added in a follow-up
patch.

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 895a07e..45dfcf5 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -655,6 +655,16 @@ mlir::Value CIRGenModule::getAddrOfGlobalVar(const VarDecl *d, mlir::Type ty,
                                           g.getSymName());
 }
 
+cir::GlobalViewAttr CIRGenModule::getAddrOfGlobalVarAttr(const VarDecl *d) {
+  assert(d->hasGlobalStorage() && "Not a global variable");
+  mlir::Type ty = getTypes().convertTypeForMem(d->getType());
+
+  cir::GlobalOp globalOp = getOrCreateCIRGlobal(d, ty, NotForDefinition);
+  assert(!cir::MissingFeatures::addressSpace());
+  cir::PointerType ptrTy = builder.getPointerTo(globalOp.getSymType());
+  return builder.getGlobalViewAttr(ptrTy, globalOp);
+}
+
 void CIRGenModule::emitGlobalVarDefinition(const clang::VarDecl *vd,
                                            bool isTentative) {
   if (getLangOpts().OpenCL || getLangOpts().OpenMPIsTargetDevice) {