GDB 18.1 asks for existing .gdb_index sections to be regenerated after a type-lookup fix

GDB 18.1 now puts all type symbols into the .gdb_index section ^[2]. According to the release notes, the change fixes cases where GDB "could fail to find a type when relying on the index." The next line says: "Existing indexes should be regenerated." ^[2]

The upgrade costs time at the regeneration step. If a build step writes the index into shipped binaries or debug-info files, that index came from whichever GDB the build image pinned. Installing a newer debugger to read it does not rewrite it. The notes do not say whether 18.1 recovers the missing types from an older index ^[2]. I would treat old indexes as incomplete and rebuild them in the same change that moves the pin.

The second thing to test is output. The notes give a Windows example: "C:/proj/src\main.c" now appears as "C:/proj/src/main.c" everywhere GDB prints a file or directory name ^[3]. A harness that compares breakpoint locations against the mixed-slash form will fail on the new string. On Windows Terminal, when the output codepage is 65001, GDB now sets the host charset to UTF-8 by itself and turns on emoji styling ^[17]. I have yet to see a CI log that wanted emoji. On every host, `info locals` now adds a "shadowed" annotation and location information for variables that shadow others or are shadowed by them ^[18]. `info inferiors` now shows any loaded core file ^[19]. Any script that scrapes CLI text needs a diff against 18.1 output.

Phoronix wrote that Windows "is seeing a lot of love" in this release ^[16], and it also reports a new AArch64 MinGW target ^[5]. The change I would single out is smaller. The `add-inferior`, `clone-inferior` and MI `-add-inferior` commands used to tend to crash GDB when asked to share a connection that cannot be shared, such as a core file or the Windows native target ^[6]. In 18.1 they print a warning and create the new inferior without a connection ^[6].

Launch wrappers get new options. `--no-escape-args` is an alternative to `--args` that does not escape special shell characters, and gdbserver accepts the same flag ^[7]. Quoted arguments to `set args`, `run`, `start` and `starti` may now contain a newline ^[7]. If a remote server supports the new qExecAndArgs packet, GDB copies the server's argument string into its own args setting. `show args` then displays it, and later runs reuse it ^[8]. On extended-remote targets, GDB can now set `remote exec-file` from the current executable when neither the server nor the user supplied one ^[9]. Serial connections accept arbitrary baud rates on systems whose libc takes them through cfsetispeed/cfsetospeed, as glibc 2.42 and later does ^[14].

Images that build from source can pin the xz tarball, 22MiB, by its sha256, cd9fc3fe2b47743840e42c1592d3d87f8302eb18639c0b8b4ba0898002e2348f ^[10]. The gzip tarball is 37MiB ^[10], so it is 15MiB more per fetch ^[11]. The maintainers say they will post errata notes and host-specific tips as problems come up ^[12].