[Lldb-commits] [lldb] [lldb] Support DW_OP_WASM_location in DWARFExpression (PR #151010)

[David Spickett via lldb-commits]

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@@ -2300,9 +2301,40 @@ llvm::Expected<Value> DWARFExpression::Evaluate(
       break;
     }
 
+    case DW_OP_WASM_location: {
+      uint8_t wasm_op = opcodes.GetU8(&offset);
+      uint32_t index;
+
+      /* LLDB doesn't have an address space to represents WebAssembly locals,
+       * globals and operand stacks.
+       * We encode these elements into virtual registers:
+       *   | tag: 2 bits | index: 30 bits |
+       *   where tag is:
+       *    0: Not a WebAssembly location
+       *    1: Local
+       *    2: Global
+       *    3: Operand stack value
+       */
+      if (wasm_op == 3) {
+        index = opcodes.GetU32(&offset);
+        wasm_op = 2; // Global
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DavidSpickett wrote:

So if the DWARF says this is an operand stack value, we treat it as if it's a global.

...and this makes sense why exactly?

https://github.com/llvm/llvm-project/pull/151010