Fix: target: Deduplicate message strings #1527

ALTracer commented 2023年06月29日 19:12:51 +02:00 (Migrated from github.com)

Detailed description

• No new feature implemented.
• This pull request is aimed at flash size/footprint reduction.
• Repeated parts of message strings in stm32l4 & samx5x could be output via %s of tc_printf/gdb_voutf/vasprintf, and this allows GCC to fold string literal constants, saving 200 bytes in .rodata.

Disclaimer: I don't have targets handled by stm32l4 code available (and certainly not samx5x), so I can't runtime-test whether the probe now crashes at this stack depth etc.
Additionally, I didn't find a tc_puts() or something similar to print simple \n0円-terminated string literals. GCC is known to optimise such calls of printf("...\n") to puts("...") (see gimple_fold_builtin_printf()). Some of the changes could be alternatively split into two print statements, the second printing the common/folded message part.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native)
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

## Detailed description * No new feature implemented. * This pull request is aimed at flash size/footprint reduction. * Repeated parts of message strings in stm32l4 & samx5x could be output via `%s` of tc_printf/gdb_voutf/vasprintf, and this allows GCC to fold string literal constants, saving 200 bytes in `.rodata`. Disclaimer: I don't have targets handled by stm32l4 code available (and certainly not samx5x), so I can't runtime-test whether the probe now crashes at this stack depth etc. Additionally, I didn't find a `tc_puts()` or something similar to print simple `\n0円`-terminated string literals. GCC is known to optimise such calls of `printf("...\n")` to `puts("...")` (see `gimple_fold_builtin_printf()`). Some of the changes could be alternatively split into two print statements, the second printing the common/folded message part. ## Your checklist for this pull request * [x] I've read the [Code of Conduct](https://github.com/blackmagic-debug/blackmagic/blob/main/CODE_OF_CONDUCT.md) * [x] I've read the [guidelines for contributing](https://github.com/blackmagic-debug/blackmagic/blob/main/CONTRIBUTING.md) to this repository * [x] It builds for hardware native (`make PROBE_HOST=native`) * [x] It builds as BMDA (`make PROBE_HOST=hosted`) * [x] I've tested it to the best of my ability * [x] My commit messages provide a useful short description of what the commits do