[lldb] Encode operands and arity in Dwarf.def and use them in LLDB. (#94679)

This PR extends Dwarf.def to include the number of operands and the arity (the
number of entries on the DWARF stack).

  - The arity is used in LLDB's DWARF expression evaluator.
  - The number of operands is unused, but is present in the table to avoid
    confusing the arity with the operands. Keeping the latter up to date should
    be straightforward as it maps directly to a table present in the DWARF
    standard.

1 files changed, 30 insertions, 4 deletions

diff --git a/llvm/lib/BinaryFormat/Dwarf.cpp b/llvm/lib/BinaryFormat/Dwarf.cpp
index 0bf4f20..0cd5dfb 100644
--- a/llvm/lib/BinaryFormat/Dwarf.cpp
+++ b/llvm/lib/BinaryFormat/Dwarf.cpp
@@ -139,7 +139,7 @@ StringRef llvm::dwarf::OperationEncodingString(unsigned Encoding) {
   switch (Encoding) {
   default:
     return StringRef();
-#define HANDLE_DW_OP(ID, NAME, VERSION, VENDOR)                                \
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
   case DW_OP_##NAME:                                                           \
     return "DW_OP_" #NAME;
 #include "llvm/BinaryFormat/Dwarf.def"
@@ -164,7 +164,7 @@ StringRef llvm::dwarf::OperationEncodingString(unsigned Encoding) {
 
 unsigned llvm::dwarf::getOperationEncoding(StringRef OperationEncodingString) {
   return StringSwitch<unsigned>(OperationEncodingString)
-#define HANDLE_DW_OP(ID, NAME, VERSION, VENDOR)                                \
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
   .Case("DW_OP_" #NAME, DW_OP_##NAME)
 #include "llvm/BinaryFormat/Dwarf.def"
       .Case("DW_OP_LLVM_convert", DW_OP_LLVM_convert)
@@ -216,18 +216,44 @@ unsigned llvm::dwarf::OperationVersion(dwarf::LocationAtom Op) {
   switch (Op) {
   default:
     return 0;
-#define HANDLE_DW_OP(ID, NAME, VERSION, VENDOR)                                \
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
   case DW_OP_##NAME:                                                           \
     return VERSION;
 #include "llvm/BinaryFormat/Dwarf.def"
   }
 }
 
+std::optional<unsigned> llvm::dwarf::OperationOperands(dwarf::LocationAtom Op) {
+  switch (Op) {
+  default:
+    return std::nullopt;
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
+  case DW_OP_##NAME:                                                           \
+    if (OPERANDS == -1)                                                        \
+      return std::nullopt;                                                     \
+    return OPERANDS;
+#include "llvm/BinaryFormat/Dwarf.def"
+  }
+}
+
+std::optional<unsigned> llvm::dwarf::OperationArity(dwarf::LocationAtom Op) {
+  switch (Op) {
+  default:
+    return std::nullopt;
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
+  case DW_OP_##NAME:                                                           \
+    if (ARITY == -1)                                                           \
+      return std::nullopt;                                                     \
+    return ARITY;
+#include "llvm/BinaryFormat/Dwarf.def"
+  }
+}
+
 unsigned llvm::dwarf::OperationVendor(dwarf::LocationAtom Op) {
   switch (Op) {
   default:
     return 0;
-#define HANDLE_DW_OP(ID, NAME, VERSION, VENDOR)                                \
+#define HANDLE_DW_OP(ID, NAME, OPERANDS, ARITY, VERSION, VENDOR)               \
   case DW_OP_##NAME:                                                           \
     return DWARF_VENDOR_##VENDOR;
 #include "llvm/BinaryFormat/Dwarf.def"