From 7d01b85c2a0aa8bc91f731cfeb2a7b6885b8d04a Mon Sep 17 00:00:00 2001
From: David Spickett <david.spickett@linaro.org>
Date: Fri, 2 May 2025 12:54:03 +0000
Subject: Reland "[lldb] Do not bump memory modificator ID when "internal"
 debugger memory is updated (#129092)"

This reverts commit daa4061d61216456baa83ab404e096200e327fb4.

Original PR https://github.com/llvm/llvm-project/pull/129092.

I have restricted the test to X86 Windows because it turns out the only
reason that `expr x.get()` would change m_memory_id is that on x86 we
have to write the return address to the stack in ABIWindows_X86_64::PrepareTrivialCall:
```
  // Save return address onto the stack
  if (!process_sp->WritePointerToMemory(sp, return_addr, error))
    return false;
```

This is not required on AArch64 so m_memory_id was not changed:
```
(lldb) expr x.get()
(int) $0 = 0
(lldb) process status -d
Process 15316 stopped
* thread #1, stop reason = Exception 0x80000003 encountered at address 0x7ff764a31034
    frame #0: 0x00007ff764a31038 TestProcessModificationIdOnExpr.cpp.tmp`main at TestProcessModificationIdOnExpr.cpp:35
   32     __builtin_debugtrap();
   33     __builtin_debugtrap();
   34     return 0;
-> 35   }
   36
   37   // CHECK-LABEL: process status -d
   38   // CHECK: m_stop_id: 2
ProcessModID:
  m_stop_id: 3
  m_last_natural_stop_id: 0
  m_resume_id: 0
  m_memory_id: 0
```

Really we should find a better way to force a memory write here, but
I can't think of one right now.
---
 lldb/source/Commands/CommandObjectProcess.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'lldb/source/Commands/CommandObjectProcess.cpp')

diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index ed80c854ed66..d0f5eaf2dfd9 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -1388,6 +1388,9 @@ public:
       case 'v':
         m_verbose = true;
         break;
+      case 'd':
+        m_dump = true;
+        break;
       default:
         llvm_unreachable("Unimplemented option");
       }
@@ -1397,6 +1400,7 @@ public:
 
     void OptionParsingStarting(ExecutionContext *execution_context) override {
       m_verbose = false;
+      m_dump = false;
     }
 
     llvm::ArrayRef<OptionDefinition> GetDefinitions() override {
@@ -1405,6 +1409,7 @@ public:
 
     // Instance variables to hold the values for command options.
     bool m_verbose = false;
+    bool m_dump = false;
   };
 
 protected:
@@ -1459,6 +1464,14 @@ protected:
         crash_info_sp->GetDescription(strm);
       }
     }
+
+    if (m_options.m_dump) {
+      StateType state = process->GetState();
+      if (state == eStateStopped) {
+        ProcessModID process_mod_id = process->GetModID();
+        process_mod_id.Dump(result.GetOutputStream());
+      }
+    }
   }
 
 private:
-- 
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