Add `gdb-repr` directive for `tests/debuginfo` by Walnut356 · Pull Request #160377 · rust-lang/rust

Walnut356 · 2026-08-02T09:39:25Z

Part of #148483 and followup to #158298. Applies (approximately) identical logic to GDB.

I still need to test things on windows-gnu (and locally try a few more tests to see if there's any glaring issues). There's also a few bike-sheddy things.

The main way this differs from the LLDB implementation is that GDB doesn't use lldb_batchmode/runner.py to orchestrate the commands. Instead, I have compiletest import from_gdb.py which registers a custom repr CLI command. GDB's batch processing works as normal, but dispatches to our logic automatically whenever it encounters repr <var_name>.

An additional repr-finalize CLI command is also registered to implement the checks that ensure we encountered all expected types/vars, and verifies that there were no errors before saving blessed data.

r? @Kobzol, @jieyouxu

rustbot · 2026-08-02T09:39:30Z

Kobzol is not on the review rotation at the moment.
They may take a while to respond.

Walnut356 · 2026-08-02T09:41:08Z

+class ReprCommand(gdb.Command):
+    def __init__(self):
+        super().__init__("repr", gdb.COMMAND_OBSCURE)
+
+    def invoke(self, argument: str, from_tty: bool):
+        print(f"(gdb) repr {argument}")
+
+        global REPR_COMMAND_RUN
+        REPR_COMMAND_RUN = True
+        try:
+            if check(argument) == Result.Mismatch:
+                global REPR_ERROR
+                REPR_ERROR = True
+        except Exception as e:
+            import sys
+            import traceback
+
+            traceback.print_exception(type(e), e, e.__traceback__, file=sys.stdout)
+            gdb.execute("exit 1")
+
+
+ReprCommand()
+
+
+class ReprFinalize(gdb.Command):
+    def __init__(self):
+        super().__init__("repr_finalize", gdb.COMMAND_OBSCURE)
+
+    def invoke(self, argument: str, from_tty: bool):
+        if not REPR_COMMAND_RUN:
+            return
+
+        if not tested_all_variables() or not tested_all_types():
+            gdb.execute("exit 1")
+
+        if BLESS and not REPR_ERROR:
+            gdb_version = gdb.execute("show version", to_string=True).splitlines()[0]
+            metadata = BlessMetadata(sys.version, gdb_version)
+            INPUT_DATA.save_blessing(metadata)
+
+
+ReprFinalize()


Here's where we create and register the custom CLI commands.

View changes since the review

Walnut356 · 2026-08-02T09:45:00Z

+TYPES_TESTED: dict[str, Result] = {}
+"""Since types are unique and unchanging, we only need to test each type once. This also helps
+ensure we have tested all types in `INPUT_DATA`
+"""
+
+
+VARS_TESTED: list[dict[str, Result]] = []
+"""Used to help ensure all expected variables were tested. Each element of the list corresponds to a
+breakpoint, and contains a set of all of the variable names tested for that breakpoint."""
+
+
+def tested_all_types() -> bool:
+    """Returns true if all types in INPUT_DATA were tested this run."""
+
+    expected_types = set(INPUT_DATA.types)
+    untested_types = expected_types.difference(TYPES_TESTED.keys())
+
+    if len(untested_types) != 0:
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following types were expected, but were not \
+tested:\n  {untested_types}"
+        )
+
+    return len(untested_types) == 0
+
+
+def tested_all_variables() -> bool:
+    expected_vars = [set(vars) for vars in INPUT_DATA.breakpoints]
+    untested_vars = [
+        expected.difference(tested.keys())
+        for expected, tested in zip(expected_vars, VARS_TESTED)
+    ]
+
+    tested_not_expected = [
+        set(tested.keys()).difference(expected)
+        for expected, tested in zip(expected_vars, VARS_TESTED)
+    ]
+
+    result = True
+
+    for i, v in enumerate(untested_vars):
+        if len(v) == 0:
+            continue
+
+        result = False
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following variables were expected at \
+breakpoint#{i}, but were not tested:\n  {v}"
+        )
+
+    for i, v in enumerate(tested_not_expected):
+        if len(v) == 0:
+            continue
+
+        result = False
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following variables were tested, but do not \
+exist in the input data at breakpoint#{i}:\n  {v}"
+        )
+
+    return result


These were just moved from check_lldb.py.

I might be able to factor more of the checking logic out and share it between lldb and gdb. There are less differences for their API than I was expecting. It would probably require passing a few wrappers to the check function that abstract away the debugger-specific accesses, but we'll see.

View changes since the review

Walnut356 · 2026-08-02T09:54:46Z

-            gdb.args(debugger_opts).env("PYTHONPATH", pythonpath);
+            gdb.args(debugger_opts)
+                .env("PYTHONPATH", pythonpath)
+                .env("BATCHMODE_DEBUGGER", "gdb")


The bike-shedding I mentioned more or less has to do with these env vars and the lldb_batchmode package. With GDB support, we'll probably want to re-name lldb_batchmode (and probably rename runner.py to lldb_batchmode.py), but I'm not super happy with any of the names that came to mind. Maybe just batchmode?

View changes since the review

Batchmode sounds really opaque. I would suggest BATCHMODE => DEBUGGER_TESTER, or something like that.

Walnut356 · 2026-08-02T10:17:44Z

Oh yeah, i need to gate it so it doesn't check for the file path until a repr command has been run

Walnut356 · 2026-08-23T05:34:40Z

There's probably more I can refactor to share more code between LLDB and GDB, but for now it should be good enough.

rustbot · 2026-08-23T05:34:49Z

Some changes occurred in src/tools/compiletest

cc @jieyouxu

compiletest directives have been modified. Please add or update docs for the
new or modified directive in src/doc/rustc-dev-guide/.

Kobzol

It looks like a non-trivial amount of code is shared with LLDB, that's good! Left some comments.

I tried it locally with GDB 15.1, and it failed with the following:

compiletest output

failures:

---- [debuginfo-gdb] tests/debuginfo/basic-types/main.rs stdout ----
NOTE: compiletest thinks it is using GDB version 15001000
------gdb stdout------------------------------
GNU gdb (Ubuntu 15.1-1ubuntu1~24.04.1) 15.1
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".
To enable execution of this file add
        add-auto-load-safe-path /projects/personal/rust/rust/src/etc/gdb_load_rust_pretty_printers.py
line to your configuration file "/home/kobzol/.config/gdb/gdbinit".
To completely disable this security protection add
        set auto-load safe-path /
line to your configuration file "/home/kobzol/.config/gdb/gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
        info "(gdb)Auto-loading safe path"
Breakpoint 1 at 0x1a81: file tests/debuginfo/basic-types/main.rs, line 112.

This GDB supports auto-downloading debuginfo from the following URLs:
  <https://debuginfod.ubuntu.com>
Enable debuginfod for this session? (y or [n]) [answered N; input not from terminal]
Debuginfod has been disabled.
To make this setting permanent, add 'set debuginfod enabled off' to .gdbinit.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, main::main () at tests/debuginfo/basic-types/main.rs:112
112         _zzz(); // #break

------gdb stderr------------------------------
warning: File "/projects/personal/rust/rust/src/etc/gdb_load_rust_pretty_printers.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
Python Exception <class 'RuntimeError'>: pretty-printer already registered: builtin
/projects/personal/rust/rust/build/x86_64-unknown-linux-gnu/test/debuginfo/basic-types/main.gdb/main.debugger.script:10: Error in sourced command file:
Error occurred in Python: pretty-printer already registered: builtin

------------------------------------------

error: gdb failed to execute
status: exit status: 1
command: BATCHMODE_DEBUGGER="gdb" LLDB_BATCHMODE_BLESS_TEST_DATA="0" LLDB_BATCHMODE_INPUT_DATA_PATH="/projects/personal/rust/rust/tests/debuginfo/basic-types/gdb_input/non_windows.json" LLDB_BATCHMODE_TARGET_TRIPLE="x86_64-unknown-linux-gnu" PYTHONPATH="/projects/personal/rust/rust/src/etc" "gdb" "-quiet" "-batch" "-nx" "-command=/projects/personal/rust/rust/build/x86_64-unknown-linux-gnu/test/debuginfo/basic-types/main.gdb/main.debugger.script"
--- stdout -------------------------------
GNU gdb (Ubuntu 15.1-1ubuntu1~24.04.1) 15.1
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".
To enable execution of this file add
        add-auto-load-safe-path /projects/personal/rust/rust/src/etc/gdb_load_rust_pretty_printers.py
line to your configuration file "/home/kobzol/.config/gdb/gdbinit".
To completely disable this security protection add
        set auto-load safe-path /
line to your configuration file "/home/kobzol/.config/gdb/gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
        info "(gdb)Auto-loading safe path"
Breakpoint 1 at 0x1a81: file tests/debuginfo/basic-types/main.rs, line 112.

This GDB supports auto-downloading debuginfo from the following URLs:
  <https://debuginfod.ubuntu.com>
Enable debuginfod for this session? (y or [n]) [answered N; input not from terminal]
Debuginfod has been disabled.
To make this setting permanent, add 'set debuginfod enabled off' to .gdbinit.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, main::main () at tests/debuginfo/basic-types/main.rs:112
112         _zzz(); // #break
------------------------------------------
--- stderr -------------------------------
warning: File "/projects/personal/rust/rust/src/etc/gdb_load_rust_pretty_printers.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
Python Exception <class 'RuntimeError'>: pretty-printer already registered: builtin
/projects/personal/rust/rust/build/x86_64-unknown-linux-gnu/test/debuginfo/basic-types/main.gdb/main.debugger.script:10: Error in sourced command file:
Error occurred in Python: pretty-printer already registered: builtin
------------------------------------------

---- [debuginfo-gdb] tests/debuginfo/basic-types/main.rs stdout end ----

failures:
    [debuginfo-gdb] tests/debuginfo/basic-types/main.rs

View changes since this review

Kobzol · 2026-08-24T08:44:43Z

+            summary_ok
+            & synthetic_ok
+            & format_ok
+            & pretty_type_name_ok
+            & pretty_print_ok,


Suggested change

summary_ok

& synthetic_ok

& format_ok

& pretty_type_name_ok

& pretty_print_ok,

summary_ok

and synthetic_ok

and format_ok

and pretty_type_name_ok

and pretty_print_ok,

Kobzol · 2026-08-24T08:47:32Z

-            gdb.args(debugger_opts).env("PYTHONPATH", pythonpath);
+            gdb.args(debugger_opts)
+                .env("PYTHONPATH", pythonpath)
+                .env("BATCHMODE_DEBUGGER", "gdb")


Batchmode sounds really opaque. I would suggest BATCHMODE => DEBUGGER_TESTER, or something like that.

Walnut356 · 2026-08-28T09:32:17Z

I tried it locally with GDB 15.1, and it failed with the following:

Hmmm. I don't have super easy access to gdb 15 atm, but my best guess is it's a bug with importing GDB twice in the same script? OTOH it seems like CI runs gdb 16.3 anyway, so we should be able to just min-gdb-version and call it good.

rustbot · 2026-08-28T10:06:21Z

Some changes occurred in tests/debuginfo/basic-stepping.rs

cc @Enselic

Kobzol · 2026-08-28T15:06:44Z

@bors try jobs=x86_64-gnu

Add `gdb-repr` directive for `tests/debuginfo` try-job: x86_64-gnu

rust-bors · 2026-08-28T17:00:12Z

☀️ Try build successful (CI)
Build commit: a89712a (a89712a45cefece5e40b923d3e1de428cc2173fb)
Base parent: 344f790 (344f7902949345394fa40a5d7dda31f012ccbc0d)

Walnut356 · 2026-08-29T08:28:01Z

(just adding the min-gdb-version)

Kobzol

Thank you, the restructuralization looks good to me. I'll let @jieyouxu take a look too.

View changes since this review

jieyouxu · 2026-08-30T09:29:23Z

(Out today but have time tmrw)

@jieyouxu

Rerun `tests/debuginfo` tests if repr data has changed Resolves rust-lang#161138 This also includes the necessary checking for GDB's data even though none exists atm (rust-lang#160377 will contain the first set). The extra handling doesn't hurt anything since we have to account for all the other tests that don't have repr data anyway. In a followup, I can rename the `lldb_input` directory to something else (see: rust-lang#160137 (comment)). Doing so requires me to touch a bunch of other places where the name is used, so it should probably be it's own PR. Making sure the tests rerun when the data changes is higher priority though atm. r? @jieyouxu , @Kobzol cc @Mark-Simulacrum

@jieyouxu

Rerun `tests/debuginfo` tests if repr data has changed Resolves rust-lang#161138 This also includes the necessary checking for GDB's data even though none exists atm (rust-lang#160377 will contain the first set). The extra handling doesn't hurt anything since we have to account for all the other tests that don't have repr data anyway. In a followup, I can rename the `lldb_input` directory to something else (see: rust-lang#160137 (comment)). Doing so requires me to touch a bunch of other places where the name is used, so it should probably be it's own PR. Making sure the tests rerun when the data changes is higher priority though atm. r? @jieyouxu , @Kobzol cc @Mark-Simulacrum

@jieyouxu

Rollup merge of #161967 - Walnut356:stamp_repr_data, r=jieyouxu Rerun `tests/debuginfo` tests if repr data has changed Resolves #161138 This also includes the necessary checking for GDB's data even though none exists atm (#160377 will contain the first set). The extra handling doesn't hurt anything since we have to account for all the other tests that don't have repr data anyway. In a followup, I can rename the `lldb_input` directory to something else (see: #160137 (comment)). Doing so requires me to touch a bunch of other places where the name is used, so it should probably be it's own PR. Making sure the tests rerun when the data changes is higher priority though atm. r? @jieyouxu , @Kobzol cc @Mark-Simulacrum

rustbot · 2026-09-01T07:33:53Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

Walnut356 · 2026-09-01T07:37:36Z

I also added the GDB equivalents for "don't fully fail on types" from #161574 and dumping raw json in CI from #162002

rustbot assigned Kobzol Aug 2, 2026

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Walnut356 marked this pull request as ready for review August 23, 2026 05:34

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 23, 2026

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rust-bors Bot pushed a commit that referenced this pull request Aug 28, 2026

Auto merge of #160377 - Walnut356:gdb_di_repr, r=<try>

a89712a

Add `gdb-repr` directive for `tests/debuginfo` try-job: x86_64-gnu

Walnut356 force-pushed the gdb_di_repr branch from 8a9fc2a to 8c0ba6e Compare August 29, 2026 08:27

Walnut356 mentioned this pull request Aug 29, 2026

Rerun tests/debuginfo tests if repr data has changed #161967

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Walnut356 added 3 commits September 1, 2026 01:06

Add gdb-repr directive

391f264

convert basic-types to gdb-repr

c7fd281

rearrange debug test logic file structure

258da8b

Walnut356 force-pushed the gdb_di_repr branch from 8c0ba6e to 3f61874 Compare September 1, 2026 07:33

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Walnut356 added 2 commits September 1, 2026 03:03

output raw json on GDB test failure in CI

7ec82ba

don't fail for GDB types mismatches if the provider still works

7a8852b

Walnut356 force-pushed the gdb_di_repr branch from 3f61874 to 7a8852b Compare September 1, 2026 08:03

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