[Mlir-commits] [mlir] [mlir] Add support for DIGlobalVariable and DIGlobalVariableExpression (PR #73367)

[Justin Wilson]

================
@@ -109,3 +119,251 @@ bool MemoryEffectsAttr::isReadWrite() {
     return false;
   return true;
 }
+
+//===----------------------------------------------------------------------===//
+// DIExpression
+//===----------------------------------------------------------------------===//
+
+DIExpressionAttr DIExpressionAttr::get(MLIRContext *context) {
+  return get(context, ArrayRef<uint64_t>({}));
+}
+
+#define _FORMAT_DW_OP(x) #x
+#define FORMAT_DW_OP(NAME, VENDOR) _FORMAT_DW_OP(DW_OP_##VENDOR##_##NAME)
+
+size_t queryNumOpParams(llvm::dwarf::LocationAtom op) {
+  switch (op) {
+  case llvm::dwarf::DW_OP_addr:
+  case llvm::dwarf::DW_OP_const1u:
+  case llvm::dwarf::DW_OP_const1s:
+  case llvm::dwarf::DW_OP_const2u:
+  case llvm::dwarf::DW_OP_const2s:
+  case llvm::dwarf::DW_OP_const4u:
+  case llvm::dwarf::DW_OP_const4s:
+  case llvm::dwarf::DW_OP_const8u:
+  case llvm::dwarf::DW_OP_const8s:
+  case llvm::dwarf::DW_OP_constu:
+  case llvm::dwarf::DW_OP_consts:
+  case llvm::dwarf::DW_OP_pick:
+  case llvm::dwarf::DW_OP_plus_uconst:
+  case llvm::dwarf::DW_OP_bra:
+  case llvm::dwarf::DW_OP_skip:
+  case llvm::dwarf::DW_OP_breg0:
+  case llvm::dwarf::DW_OP_breg1:
+  case llvm::dwarf::DW_OP_breg2:
+  case llvm::dwarf::DW_OP_breg3:
+  case llvm::dwarf::DW_OP_breg4:
+  case llvm::dwarf::DW_OP_breg5:
+  case llvm::dwarf::DW_OP_breg6:
+  case llvm::dwarf::DW_OP_breg7:
+  case llvm::dwarf::DW_OP_breg8:
+  case llvm::dwarf::DW_OP_breg9:
+  case llvm::dwarf::DW_OP_breg10:
+  case llvm::dwarf::DW_OP_breg11:
+  case llvm::dwarf::DW_OP_breg12:
+  case llvm::dwarf::DW_OP_breg13:
+  case llvm::dwarf::DW_OP_breg14:
+  case llvm::dwarf::DW_OP_breg15:
+  case llvm::dwarf::DW_OP_breg16:
+  case llvm::dwarf::DW_OP_breg17:
+  case llvm::dwarf::DW_OP_breg18:
+  case llvm::dwarf::DW_OP_breg19:
+  case llvm::dwarf::DW_OP_breg20:
+  case llvm::dwarf::DW_OP_breg21:
+  case llvm::dwarf::DW_OP_breg22:
+  case llvm::dwarf::DW_OP_breg23:
+  case llvm::dwarf::DW_OP_breg24:
+  case llvm::dwarf::DW_OP_breg25:
+  case llvm::dwarf::DW_OP_breg26:
+  case llvm::dwarf::DW_OP_breg27:
+  case llvm::dwarf::DW_OP_breg28:
+  case llvm::dwarf::DW_OP_breg29:
+  case llvm::dwarf::DW_OP_breg30:
+  case llvm::dwarf::DW_OP_breg31:
+  case llvm::dwarf::DW_OP_regx:
+  case llvm::dwarf::DW_OP_fbreg:
+  case llvm::dwarf::DW_OP_piece:
+  case llvm::dwarf::DW_OP_deref_size:
+  case llvm::dwarf::DW_OP_xderef_size:
+  case llvm::dwarf::DW_OP_call2:
+  case llvm::dwarf::DW_OP_call4:
+  case llvm::dwarf::DW_OP_call_ref:
+  case llvm::dwarf::DW_OP_addrx:
+  case llvm::dwarf::DW_OP_constx:
+  case llvm::dwarf::DW_OP_convert:
+  case llvm::dwarf::DW_OP_reinterpret:
+    return 1;
+  case llvm::dwarf::DW_OP_bregx:
+  case llvm::dwarf::DW_OP_bit_piece:
+  case llvm::dwarf::DW_OP_implicit_value:
+  case llvm::dwarf::DW_OP_implicit_pointer:
+  case llvm::dwarf::DW_OP_entry_value:
+  case llvm::dwarf::DW_OP_regval_type:
+  case llvm::dwarf::DW_OP_deref_type:
+  case llvm::dwarf::DW_OP_xderef_type:
+    return 2;
+  case llvm::dwarf::DW_OP_const_type:
+    return 3;
+  default:
+    return 0;
+  }
+}
+
+::mlir::Attribute DIExpressionAttr::parse(AsmParser &parser, Type type) {
----------------
waj334 wrote:

I'm almost positive I won't be able to get this to work using the existing stuff implemented in tablegen. In order to do this properly, I would need to somehow store both the value and what DWARF kind that value is together. THEN in order to support printing the textual form, you'd need to look at the kind and choose the correct printer.

Importing LLVM IR is a whole different can of worms. Frankly DIExpression only will give a list of ints to make sense of. Figuring out operations was easy and I already implemented that, but now figuring out which operand maps to which DWARF kind is a rabbit hole I currently want to climb out of 🕳️ .

I think for the sake of getting this out, I'd rather not spend more time on getting expressions 1-to-1 with LLVM's representation. Operands as ints will work for now and anyone reading/handwriting IR can refer to the DWARF spec in the meantime. Otherwise, LLVM has enums for all of this stuff that can be used in code.

https://github.com/llvm/llvm-project/pull/73367