[Lldb-commits] [lldb] [lldb] Add DWARFExpressionEntry and GetExpressionEntryAtAddress() to … (PR #144238)

[Abdullah Mohammad Amin via lldb-commits]

https://github.com/UltimateForce21 updated https://github.com/llvm/llvm-project/pull/144238

>From 8ed8c540e7600d720a63bc2882a81a2c65c11d41 Mon Sep 17 00:00:00 2001
From: ultimateforce21 <abdullahmohammad155 at gmail.com>
Date: Wed, 11 Jun 2025 00:11:09 -0400
Subject: [PATCH 1/2] [lldb] Add DWARFExpressionEntry and
 GetExpressionEntryAtAddress() to DWARFExpressionList

This introduces a new API for retrieving DWARF expression metadata associated with variable location entries at a given PC address. It provides the base, end, and expression pointer for downstream consumers such as disassembler annotations.

Intended for use in richer instruction annotations in Instruction::Dump().
---
 .../lldb/Expression/DWARFExpressionList.h     | 12 +++++++++++
 .../source/Expression/DWARFExpressionList.cpp | 21 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/lldb/include/lldb/Expression/DWARFExpressionList.h b/lldb/include/lldb/Expression/DWARFExpressionList.h
index d8f8ec247ed56..a329b37393018 100644
--- a/lldb/include/lldb/Expression/DWARFExpressionList.h
+++ b/lldb/include/lldb/Expression/DWARFExpressionList.h
@@ -59,6 +59,18 @@ class DWARFExpressionList {
 
   lldb::addr_t GetFuncFileAddress() { return m_func_file_addr; }
 
+  /// Represents an entry in the DWARFExpressionList with all needed metadata
+  struct DWARFExpressionEntry {
+    lldb::addr_t base;
+    lldb::addr_t end;
+    const DWARFExpression *expr;
+  };
+
+  /// Returns the entry (base, end, data) for a given PC address
+  llvm::Expected<DWARFExpressionEntry>
+  GetExpressionEntryAtAddress(lldb::addr_t func_load_addr,
+                              lldb::addr_t load_addr) const;
+
   const DWARFExpression *GetExpressionAtAddress(lldb::addr_t func_load_addr,
                                                 lldb::addr_t load_addr) const;
 
diff --git a/lldb/source/Expression/DWARFExpressionList.cpp b/lldb/source/Expression/DWARFExpressionList.cpp
index 04592a1eb7ff4..b55bc7120c4af 100644
--- a/lldb/source/Expression/DWARFExpressionList.cpp
+++ b/lldb/source/Expression/DWARFExpressionList.cpp
@@ -53,6 +53,27 @@ bool DWARFExpressionList::ContainsAddress(lldb::addr_t func_load_addr,
   return GetExpressionAtAddress(func_load_addr, addr) != nullptr;
 }
 
+llvm::Expected<DWARFExpressionList::DWARFExpressionEntry>
+DWARFExpressionList::GetExpressionEntryAtAddress(lldb::addr_t func_load_addr,
+                                                 lldb::addr_t load_addr) const {
+  if (const DWARFExpression *expr = GetAlwaysValidExpr()) {
+    return DWARFExpressionEntry{0, LLDB_INVALID_ADDRESS, expr};
+  }
+
+  if (func_load_addr == LLDB_INVALID_ADDRESS)
+    func_load_addr = m_func_file_addr;
+
+  addr_t addr = load_addr - func_load_addr + m_func_file_addr;
+  uint32_t index = m_exprs.FindEntryIndexThatContains(addr);
+  if (index == UINT32_MAX) {
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "No DWARF expression found for address 0x%llx", addr);
+  }
+
+  const Entry &entry = *m_exprs.GetEntryAtIndex(index);
+  return DWARFExpressionEntry{entry.base, entry.GetRangeEnd(), &entry.data};
+}
+
 const DWARFExpression *
 DWARFExpressionList::GetExpressionAtAddress(lldb::addr_t func_load_addr,
                                             lldb::addr_t load_addr) const {

>From 1db5002a69dba4f88aaac56d61520b7b4b214b01 Mon Sep 17 00:00:00 2001
From: Abdullah Mohammad Amin
 <67847674+UltimateForce21 at users.noreply.github.com>
Date: Thu, 19 Jun 2025 11:55:35 -0400
Subject: [PATCH 2/2] Update lldb/include/lldb/Expression/DWARFExpressionList.h

Co-authored-by: Jonas Devlieghere <jonas at devlieghere.com>
---
 lldb/include/lldb/Expression/DWARFExpressionList.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lldb/include/lldb/Expression/DWARFExpressionList.h b/lldb/include/lldb/Expression/DWARFExpressionList.h
index a329b37393018..89e55ffc07659 100644
--- a/lldb/include/lldb/Expression/DWARFExpressionList.h
+++ b/lldb/include/lldb/Expression/DWARFExpressionList.h
@@ -59,7 +59,7 @@ class DWARFExpressionList {
 
   lldb::addr_t GetFuncFileAddress() { return m_func_file_addr; }
 
-  /// Represents an entry in the DWARFExpressionList with all needed metadata
+  /// Represents an entry in the DWARFExpressionList with all needed metadata.
   struct DWARFExpressionEntry {
     lldb::addr_t base;
     lldb::addr_t end;