RISC-V: List all integer registers for lldb compatibility #149
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lldb requires a full list of registers in the target_description_xml (gdb on the other hand seems to ignore the list completely). The gdb manual sounds like these registers should exist anyway: > The ‘org.gnu.gdb.riscv.cpu’ feature is required for RISC-V targets. It should contain the registers ‘x0’ through ‘x31’, and ‘pc’. Therefore it seems reasonable that the RISC-V arch returns the full list.
gdbstub_arch/src/riscv/mod.rs
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| // are permitted in any medium without royalty provided the copyright | ||
| // notice and this notice are preserved. --> | ||
| Some(r#"<target version="1.0"> | ||
| <architecture>riscv:rv32</architecture> |
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There's quite some duplication, but we can't use replace() of format! here due to require 'static string.
If preferred, I can attempt a macro solution
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Instead of hard-coding the string inline with the Rust code, can we just yoink the relevant XML files from GDB, put them alongside this mod.rs file, and use include_str! to reference them from the Rust code?
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Sounds good, will do!
danlehmann
changed the title
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Oof, ignore most of those CI errors - that's what I get for not pinning the Rust version I use in CI 😅 Still reviewing the code, but at first blush, this seems reasonable... |
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Ok swapped out for the original files. It's a cleaner solution, but one downside is that the comments in it (copyright notice) are now sent over as part of the protocol. And I guess the binary size goes up a little bit as we now also store the copyright notice in the binary. |
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Tested with both lldb and gdb with my risc-v emulator |
lldb trace |
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In terms of size impact: The original file (from gdb, with copyright notice, dtd and xml header is 2004 bytes). The shortened version I had in my earlier patch is roughly 1.5k. |
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The binary size hit is unfortunate... but I think if someone is really trying to squeeze every last byte out of their |
Before you do, let me upload the equivalent arm patch |
Actually, I just realized you only have arm4t, which my emulator does not use (it's armv6m, for which I have my own xml definition anyway). So no need to wait for anything from my end |
For what it's worth, you might want to consider upstreaming your custom Arch implementation into |
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Sure, will do! |
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Apologies for the delay - I finally found a moment to publish a new release of gdbstub_arch 😅 0.3.1 has been published to crates.io, and includes this fix :) |
Description
lldb requires a full list of registers in the target_description_xml (gdb on the other hand seems to ignore the list completely).
The gdb manual sounds like these registers should exist anyway:
Therefore it seems reasonable that the RISC-V arch returns the full list.
API Stability
Checklist
ArchimplementationValidation
LLDB output (before this change)
LLDB output (after this change)
trace (before this change)
trace (after this change)
Before/After `./example_no_std/check_size.sh` output
Before
Can't test - example_no_std doesn't build right now