[lldb] Don't send invalid region addresses to lldb server

[DavidSpickett]

Summary

Previously when <addr> in "memory region <addr>" didn't
parse correctly, we'd print an error then also ask lldb-server
for a region containing LLDB_INVALID_ADDRESS.

(lldb) memory region not_an_address
error: invalid address argument "not_an_address"...
error: Server returned invalid range

Only send the command to lldb-server if the address
parsed correctly.

(lldb) memory region not_an_address
error: invalid address argument "not_an_address"...

[labath]

lldb/source/Commands/CommandObjectMemory.cpp

1711

How about adding return false here to avoid indenting the code below?

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

44–52

If you're goal is to ensure that lldb-server is really not queried, then this would require a different kind of a test.

But if (as I suspect), you just want to ensure the error message makes sense, then it would be better to just match the full text of the error message, and drop all references to lldb-server.

[DavidSpickett]

• Return early
• Only check for expected error in TestMemoryRegion

[DavidSpickett]

lldb/source/Commands/CommandObjectMemory.cpp

1711

I was trying to match the rest, but yes there is no sense making it more complicated.

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

44–52

It's both, that you get an error that makes sense but also that we don't then carry on regardless. I suppose there's no guarantee that that second error is caused by sending a qMemoryRegion packet so it isn't very exact.

I'll add a second test that checks that the specific packets are not sent after the first error.

[labath]

lldb/source/Commands/CommandObjectMemory.cpp

1711

Yeah, that's the old style of things, but we're currently changing things to use early exits where possible. If I was doing this, I'd early-exitify the whole function, but I did not want to make you do that for such a simple fix.

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

44–52

Right, but this won't check that the second message is not displayed, will it? I thought we'd change this to an exact string match instead of a regex. It won't be consistent with the surrounding code, but it could be argued that the surrounding code should also be changed to use exact matches in order to ensure the error messages are really reasonable...

I'm not convinced of the value of the other test, but I won't stop you from adding it. :)

[DavidSpickett]

• Check complete error message instead of using regex

[DavidSpickett]

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

44–52

Right, I misunderstood. (also not sure my first version did what I thought it did either)

Changed to match the full error message, that should cover it. If you did carry on you'd get some other message that won't match, from lldb-server or otherwise.

[labath]

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

44–52

Awesome. In fact, now that we have the full error message, we can see that's still kinda redundant. But that's for another patch...

lldb/source/Commands/CommandObjectMemory.cpp

 //===-- CommandObjectMemory.cpp -------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
if (process_sp) {
           auto load_addr_str = command[0].ref();
           load_addr = OptionArgParser::ToAddress(&m_exe_ctx, load_addr_str,
                                                  LLDB_INVALID_ADDRESS, &error);
           if (error.Fail() || load_addr == LLDB_INVALID_ADDRESS) {
             result.AppendErrorWithFormat(
                 "invalid address argument \"%s\": %s\n", command[0].c_str(),
                 error.AsCString());
             result.SetStatus(eReturnStatusFailed);
+            return false;
           }
         }
 
         lldb_private::MemoryRegionInfo range_info;
         error = process_sp->GetMemoryRegionInfo(load_addr, range_info);
         if (error.Success()) {
           lldb_private::Address addr;
           ConstString name = range_info.GetName();
           ConstString section_name;

lldb/test/API/functionalities/memory-region/TestMemoryRegion.py

def test(self):
         interp = self.dbg.GetCommandInterpreter()
         result = lldb.SBCommandReturnObject()
 
         # Test that the first 'memory region' command prints the usage.
         interp.HandleCommand("memory region", result)
         self.assertFalse(result.Succeeded())
         self.assertRegexpMatches(result.GetError(), "Usage: memory region ADDR")
 
+        # Test that when the address fails to parse, we show an error and do not continue
+        interp.HandleCommand("memory region not_an_address", result)
+        self.assertFalse(result.Succeeded())
+        self.assertEqual(result.GetError(),
+                "error: invalid address argument \"not_an_address\": address expression \"not_an_address\" evaluation failed\n")
+
         # Now let's print the memory region starting at 0 which should always work.
         interp.HandleCommand("memory region 0x0", result)
         self.assertTrue(result.Succeeded())
         self.assertRegexpMatches(result.GetOutput(), "\\[0x0+-")
 
         # Keep printing memory regions until we printed all of them.
         while True:
             interp.HandleCommand("memory region", result)
             if not result.Succeeded():
                 break
 
         # Now that we reached the end, 'memory region' should again print the usage.
         interp.HandleCommand("memory region", result)
         self.assertFalse(result.Succeeded())
         self.assertRegexpMatches(result.GetError(), "Usage: memory region ADDR")