https://github.com/paolosevMSFT created
https://github.com/llvm/llvm-project/pull/78977
Add support for `DW_OP_WASM_location` in `DWARFExpression`.
>From 4bcf2b50123b18752108aad163a059577e360aa6 Mon Sep 17 00:00:00 2001
From: Paolo Severini <paolo...@microsoft.com>
Date: Mon, 22 Jan 2024 06:06:56 -0800
Subject: [PATCH] Add support for DW_OP_WASM_location to DWARFExpression
---
lldb/source/Expression/DWARFExpression.cpp | 41 ++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/lldb/source/Expression/DWARFExpression.cpp
b/lldb/source/Expression/DWARFExpression.cpp
index fe4928d4f43a434..95033db5ed8f5a1 100644
--- a/lldb/source/Expression/DWARFExpression.cpp
+++ b/lldb/source/Expression/DWARFExpression.cpp
@@ -346,6 +346,16 @@ static offset_t GetOpcodeDataSize(const DataExtractor
&data,
return (offset - data_offset) + subexpr_len;
}
+ case DW_OP_WASM_location: {
+ uint8_t wasm_op = data.GetU8(&offset);
+ if (wasm_op == 3) {
+ data.GetU32(&offset);
+ } else {
+ data.GetULEB128(&offset);
+ }
+ return offset - data_offset;
+ }
+
default:
if (!dwarf_cu) {
return LLDB_INVALID_OFFSET;
@@ -2595,6 +2605,37 @@ bool 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
+ } else {
+ index = opcodes.GetULEB128(&offset);
+ }
+
+ reg_num = (((wasm_op + 1) & 0x03) << 30) | (index & 0x3fffffff);
+
+ if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr,
tmp))
+ stack.push_back(tmp);
+ else
+ return false;
+
+ break;
+ }
+
default:
if (dwarf_cu) {
if (dwarf_cu->GetSymbolFileDWARF().ParseVendorDWARFOpcode(
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