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* [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
@ 2023-11-23 17:26 tpzker at thepuzzlemaker dot info
2023-11-23 17:37 ` [Bug rust/31082] " tpzker at thepuzzlemaker dot info
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: tpzker at thepuzzlemaker dot info @ 2023-11-23 17:26 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
Bug ID: 31082
Summary: rust-parse infers `0xffffffd00000009a` and other
addresses as i128, preventing `as *mut _` coercions in
`print`
Product: gdb
Version: HEAD
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: rust
Assignee: unassigned at sourceware dot org
Reporter: tpzker at thepuzzlemaker dot info
Target Milestone: ---
Created attachment 15226
--> https://sourceware.org/bugzilla/attachment.cgi?id=15226&action=edit
[PATCH] rust-parse: Infer some integer constants as u64
I've been working on an operating system in Rust for learning purposes, and
have found myself having to deal with addresses greater than `2^63-1` due to
canonicalization and higher-half kernels. Due to a bug (#29735) in GDB 13.2,
fixed in GDB 14 HEAD, however, I have been using the GDB 14 branch to perform
debugging.
However, when trying to print expressions as such:
```
p (0xffffffd00000009a as *mut u64)
```
The system returns an error: `That operation is not available on integers of
more than 8 bytes.`
To reproduce this, compile a simple Rust program like such (in `tmp.rs`, for
example):
```rs
fn main() { println!("hello world!") }
```
Then `b tmp::main` and run the print command above.
After some debugging, I've discovered that this stems from the following patch:
https://sourceware.org/pipermail/gdb-patches/2023-March/198410.html
This patch added support for `i128`, however in this process, made all `u64`s
`(2 ** 63) - 1 <= x <= (2 ** 64) - 1` inferred to be i128s, when they really
should be `u64`s. This causes the `as *mut u64` operation to fail.
This only occurs for addresses in the higher half, and not any other
addresses--perhaps why it was not discovered earlier.
I have attached a patch that is a bit hacky, but does solve this issue. It will
regress some inference of large values as i128, however, and that will require
explicit suffixing as `[number]i128`. I'm not sure how to better solve that,
though.
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
@ 2023-11-23 17:37 ` tpzker at thepuzzlemaker dot info
2023-11-24 16:37 ` tromey at sourceware dot org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: tpzker at thepuzzlemaker dot info @ 2023-11-23 17:37 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
The Puzzlemaker <tpzker at thepuzzlemaker dot info> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |tpzker at thepuzzlemaker dot info
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
2023-11-23 17:37 ` [Bug rust/31082] " tpzker at thepuzzlemaker dot info
@ 2023-11-24 16:37 ` tromey at sourceware dot org
2023-11-24 16:56 ` tromey at sourceware dot org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: tromey at sourceware dot org @ 2023-11-24 16:37 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
Tom Tromey <tromey at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2023-11-24
CC| |tromey at sourceware dot org
Ever confirmed|0 |1
--- Comment #1 from Tom Tromey <tromey at sourceware dot org> ---
FWIW you can reproduce it without a program at all, just "set lang rust".
I tend to think value_cast can be fixed instead. This bug probably
affects any language that can create a 128-bit integer.
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
2023-11-23 17:37 ` [Bug rust/31082] " tpzker at thepuzzlemaker dot info
2023-11-24 16:37 ` tromey at sourceware dot org
@ 2023-11-24 16:56 ` tromey at sourceware dot org
2023-11-25 2:26 ` tromey at sourceware dot org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: tromey at sourceware dot org @ 2023-11-24 16:56 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
Tom Tromey <tromey at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at sourceware dot org |tromey at sourceware dot org
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
` (2 preceding siblings ...)
2023-11-24 16:56 ` tromey at sourceware dot org
@ 2023-11-25 2:26 ` tromey at sourceware dot org
2023-12-08 15:39 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: tromey at sourceware dot org @ 2023-11-25 2:26 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
--- Comment #2 from Tom Tromey <tromey at sourceware dot org> ---
https://sourceware.org/pipermail/gdb-patches/2023-November/204503.html
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
` (3 preceding siblings ...)
2023-11-25 2:26 ` tromey at sourceware dot org
@ 2023-12-08 15:39 ` cvs-commit at gcc dot gnu.org
2023-12-08 15:39 ` tromey at sourceware dot org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-12-08 15:39 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
--- Comment #3 from Sourceware Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom Tromey <tromey@sourceware.org>:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=44671f3f7f4c6435e7a639ad2215629f4e1ea8a7
commit 44671f3f7f4c6435e7a639ad2215629f4e1ea8a7
Author: Tom Tromey <tom@tromey.com>
Date: Fri Nov 24 12:10:53 2023 -0700
Allow cast of 128-bit integer to pointer
PR rust/31082 points out that casting a 128-bit integer to a pointer
will fail. This happens because a case in value_cast was not
converted to use GMP.
This patch fixes the problem. I am not really sure that testing
against the negative value here makes sense, but I opted to just
preserve the existing behavior rather than change it.
Regression tested on x86-64 Fedora 38.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31082
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
` (4 preceding siblings ...)
2023-12-08 15:39 ` cvs-commit at gcc dot gnu.org
@ 2023-12-08 15:39 ` tromey at sourceware dot org
2024-11-01 7:36 ` dajiang0055 at gmail dot com
2024-11-01 23:34 ` tromey at sourceware dot org
7 siblings, 0 replies; 9+ messages in thread
From: tromey at sourceware dot org @ 2023-12-08 15:39 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
Tom Tromey <tromey at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |15.1
--- Comment #4 from Tom Tromey <tromey at sourceware dot org> ---
Fixed.
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
` (5 preceding siblings ...)
2023-12-08 15:39 ` tromey at sourceware dot org
@ 2024-11-01 7:36 ` dajiang0055 at gmail dot com
2024-11-01 23:34 ` tromey at sourceware dot org
7 siblings, 0 replies; 9+ messages in thread
From: dajiang0055 at gmail dot com @ 2024-11-01 7:36 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
dajiang0055 at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |dajiang0055 at gmail dot com
--- Comment #5 from dajiang0055 at gmail dot com ---
(In reply to Tom Tromey from comment #4)
> Fixed.
Hi, this fix will break mips target. For mips target, the address 0x80ffffac
will
sign extended to 0xffffffff80ffffac
see also https://sourceware.org/pipermail/binutils/2002-September/021970.html
Breakpoint 1, main () at gdb/testsuite/gdb.base/advance.c:43
43 c = 5;
(gdb) watch -l b
warning: value truncated
Hardware watchpoint 3: -location b
(gdb) p/x &b
$1 = 0x80ffffac
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* [Bug rust/31082] rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print`
2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
` (6 preceding siblings ...)
2024-11-01 7:36 ` dajiang0055 at gmail dot com
@ 2024-11-01 23:34 ` tromey at sourceware dot org
7 siblings, 0 replies; 9+ messages in thread
From: tromey at sourceware dot org @ 2024-11-01 23:34 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=31082
Tom Tromey <tromey at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|FIXED |---
--- Comment #6 from Tom Tromey <tromey at sourceware dot org> ---
Not really fixed.
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2023-11-23 17:26 [Bug rust/31082] New: rust-parse infers `0xffffffd00000009a` and other addresses as i128, preventing `as *mut _` coercions in `print` tpzker at thepuzzlemaker dot info
2023-11-23 17:37 ` [Bug rust/31082] " tpzker at thepuzzlemaker dot info
2023-11-24 16:37 ` tromey at sourceware dot org
2023-11-24 16:56 ` tromey at sourceware dot org
2023-11-25 2:26 ` tromey at sourceware dot org
2023-12-08 15:39 ` cvs-commit at gcc dot gnu.org
2023-12-08 15:39 ` tromey at sourceware dot org
2024-11-01 7:36 ` dajiang0055 at gmail dot com
2024-11-01 23:34 ` tromey at sourceware dot org
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