[lldb] Wrong map node type after Xcode upgrade 16.2->16.4

[nd-work]

To reproduce debug the program and examine map[0]:

#include <map>

int main() {
  std::map<int, int> map;
  map[1] = 1;
  return 0; //break
}

Xcode 16.2:

% lldb test
(lldb) target create ".../test"
Current executable set to '.../test' (arm64).
(lldb) version
lldb-1600.0.39.109
Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
(lldb) b main.cpp:6
Breakpoint 1: where = test`main + 68 at main.cpp:6:3, address = 0x0000000100000d0c
(lldb) run
Process 23526 launched: '.../test' (arm64)
Process 23526 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
    frame #0: 0x0000000100000d0c test`main at main.cpp:6:3
   3   	int main() {
   4   	  std::map<int, int> map;
   5   	  map[1] = 1;
-> 6   	  return 0;
   7   	}
(lldb) frame variable map[0]
(std::__1::pair<const int, int>) map[0] = (first = 1, second = 1)
(lldb)

Xcode 16.4:

% lldb test
(lldb) target create ".../test"
Current executable set to '.../test' (arm64).
(lldb) version
lldb-1700.0.9.502
Apple Swift version 6.1.2 (swiftlang-6.1.2.1.2 clang-1700.0.13.5)
(lldb) b main.cpp:6
Breakpoint 1: where = test`main + 68 at main.cpp:6:3, address = 0x0000000100000d0c
(lldb) run
Process 23532 launched: '.../test' (arm64)
Process 23532 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
    frame #0: 0x0000000100000d0c test`main at main.cpp:6:3
   3   	int main() {
   4   	  std::map<int, int> map;
   5   	  map[1] = 1;
-> 6   	  return 0;
   7   	}
Target 0: (test) stopped.
(lldb) frame variable map[0]
(std::__1::__value_type<int, int>::value_type) map[0] = (first = 1, second = 1)

[llvmbot]

@llvm/issue-subscribers-lldb

Author: None (nd-work)

To reproduce debug the program and examine `map[0]`:

#include <map>

int main() {
  std::map<int, int> map;
  map[1] = 1;
  return 0; //break
}

Xcode 16.2:

% lldb test
(lldb) target create ".../test"
Current executable set to '.../test' (arm64).
(lldb) version
lldb-1600.0.39.109
Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
(lldb) b main.cpp:6
Breakpoint 1: where = test`main + 68 at main.cpp:6:3, address = 0x0000000100000d0c
(lldb) run
Process 23526 launched: '.../test' (arm64)
Process 23526 stopped
* thread #<!-- -->1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
    frame #<!-- -->0: 0x0000000100000d0c test`main at main.cpp:6:3
   3   	int main() {
   4   	  std::map&lt;int, int&gt; map;
   5   	  map[1] = 1;
-&gt; 6   	  return 0;
   7   	}
(lldb) frame variable map[0]
(std::__1::pair&lt;const int, int&gt;) map[0] = (first = 1, second = 1)
(lldb)

Xcode 16.4:

% lldb test
(lldb) target create ".../test"
Current executable set to '.../test' (arm64).
(lldb) version
lldb-1700.0.9.502
Apple Swift version 6.1.2 (swiftlang-6.1.2.1.2 clang-1700.0.13.5)
(lldb) b main.cpp:6
Breakpoint 1: where = test`main + 68 at main.cpp:6:3, address = 0x0000000100000d0c
(lldb) run
Process 23532 launched: '.../test' (arm64)
Process 23532 stopped
* thread #<!-- -->1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
    frame #<!-- -->0: 0x0000000100000d0c test`main at main.cpp:6:3
   3   	int main() {
   4   	  std::map&lt;int, int&gt; map;
   5   	  map[1] = 1;
-&gt; 6   	  return 0;
   7   	}
Target 0: (test) stopped.
(lldb) frame variable map[0]
(std::__1::__value_type&lt;int, int&gt;::value_type) map[0] = (first = 1, second = 1)

[Michael137]

The type itself isn't "wrong". We just show the value_type typedef instead of the pair that it resolves to. It could be a consequence of this revert, though need to double check

Here's the value_type typedef when compiling your example:

0x00000e42:       DW_TAG_structure_type
                    DW_AT_calling_convention    (DW_CC_pass_by_value)
                    DW_AT_name  ("__value_type<int, int>")
                    DW_AT_byte_size     (0x08)

                   ....
0x00000e62:         DW_TAG_typedef
                      DW_AT_type        (0x0000000000000690 "std::__1::pair<const int, int>")
                      DW_AT_name        ("value_type")