feat(libSceLibcInternal): implement the codecvt<char, char> members - #15721

What

This implements nine std::codecvt<char, char, _Mbstatet> members in libSceLibcInternal. On main each one threw through NotImplemented_nid_no_patch (sceLibcInternalPending3_027..035 in Err.cpp):

The behaviour comes from [locale.codecvt.virtuals] (checked against the current draft, eel.is/c++draft/locale.codecvt.virtuals) and matches microsoft/STL e1ed302683 stl/inc/xlocale:

• do_in and do_out: Table 93 gives noconv when "internT and externT are the same type, and input sequence is identical to converted sequence"; from_next = from, to_next = to.
• do_unshift: Table 94 gives noconv when "no termination is needed for this state_type"; xlocale L738-L742 sets _Mid2 = _First2 and returns noconv.
• do_always_noconv: "codecvt<char, char, mbstate_t> returns true."
• do_length: for this specialization, "returns the lesser of max and (from_end - from)".

[locale.codecvt.members] makes each public member return its do_ member. For example in is "Returns: do_in(state, from, from_end, from_next, to, to_end, to_next)".

libc already holds these conversions. _ZNSt7codecvtIcc9_MbstatetE7_Getcat builds its C-locale facet on g_codecvtVtable in core/libs/prx/libc/src/LocaleSupport.cpp:

const GuestLocale::CodecvtVtable g_codecvtVtable{{DestroyCollate, DeleteCollate, RetainFacet, ReleaseFacet}, CodecvtAlwaysNoconv, CodecvtConstantOne, CodecvtConstantOne, CodecvtNoConversion, CodecvtNoConversion, CodecvtUnshift, CodecvtLength};

The slot layout is pinned in GuestLocale.hpp by static_assert(offsetof(CodecvtVtable, alwaysNoconv) == 0x20), in == 0x38 and length == 0x50. Following #14373, which reaches libc's numpunct<char> helpers through a libc header instead of copying them, libc now returns that table from LibcCodecvtMethods_nid_no_patch(), declared in prx/libc/include/GuestLocale.hpp. The _nid_no_patch suffix keeps it out of the NID tables, so libc gets no new export and only libSceLibcInternal's exports change. Unlike #14373, no _nid_postfix symbol is added to libc: the 13.60 export inventory (ps5-1360-stubs) and its verified name map list these nine names only under libSceLibcInternal, and the inventory has no libc library at all, so nothing grounds them as libc.prx exports.

The new core/libs/prx/libSceLibcInternal/Codecvt.cpp holds the nine exports:

• The do_ members call the matching slot of LibcCodecvtMethods_nid_no_patch(): CodecvtAlwaysNoconv, CodecvtNoConversion, CodecvtUnshift and CodecvtLength. They never read the facet's own vtable, so a derived facet that calls codecvt::do_in gets the base behaviour.
• The public members call the facet's own vtable slot, so a title's derived facet runs its overrides. A null facet, or a facet with no vtable, makes them throw std::invalid_argument.

This PR also changes existing libc behaviour. On main, libc's CodecvtUnshift (the unshift slot of every codecvt<char, char> facet _Getcat builds) returned ok (0). It now returns noconv (3). [locale.codecvt.virtuals] Table 94 defines noconv as "no termination is needed for this state_type", which holds for the stateless char-to-char facet, and microsoft/STL e1ed302683 stl/inc/xlocale L738-L742 returns noconv from do_unshift. The test covers it: guest_libc_internal_codecvt checks do_unshift and unshift on the _Getcat facet return noconv, and the existing assertion in core/libs/tests/GuestLocale.cpp is updated from == 0 to == 3.

The standard length and do_length return int, but the vtable slot is typed std::size_t. Both therefore keep only the low 32 bits of the slot's result. This gives the right value when a guest override returns int in eax and leaves the upper half of rax undefined.

Changes:

• New file core/libs/prx/libSceLibcInternal/Codecvt.cpp. The nine stubs are removed from Err.cpp. The entry points are declared in prx/libSceLibcInternal/include/Api.hpp.
• core/libs/prx/libc/src/LocaleSupport.cpp: LibcCodecvtMethods_nid_no_patch() and the CodecvtUnshift result.
• New guest test guest_libc_internal_codecvt (core/libs/tests/GuestLibcInternalCodecvt.cpp). It checks:
  • every do_ and public member on the facet _Getcat builds;
  • both orders of max against the range length, and an empty range;
  • that the state and the output buffer are left untouched;
  • that in, out, unshift and length reach an overriding facet's slots with their arguments and return its results, including length dropping the upper 32 bits of a do_length result;
  • that the do_ members called on that overriding facet still give the base results;
  • that the four public members throw std::invalid_argument for a null facet and for a facet with no vtable.
• docs/dev/debt/libSceLibcInternal.md: the nine "prototype and behavior are unverified" lines are removed. A Functional entry is added for what the console was not checked for.

tools/progress.py collect_libraries():

• origin/main (b11c7bf84f): 9921 done of 37146 (libSceLibcInternal 92 done, 1045 todo; libc 1628 done, 19 todo).
• This branch: 9930 done of 37146 (libSceLibcInternal 101 done, 1036 todo; libc 1628 done, 19 todo).
• Done goes up by 9: the nine libSceLibcInternal members. libc's counts do not change and no new todo appears.

Tested

Only the libraries and the focused test targets were built, on head 24e372834e (based on origin/main b11c7bf84f). No title was run.

• Windows 11, WinLibs GCC 15.2.0 (MinGW-w64), Release: ctest -R '^(guest_libc_internal_codecvt|guest_locale|guest_err|conventions_unknown_nids|conventions_debt_length|conventions_doc_links|debt_split)$' ran 3 times. Each run passed 7 of 7 tests with 0 failures.
• WSL Ubuntu 22.04, GCC 11.4.0, Release, the same head: the same 7 tests ran 3 times, and each run passed 7 of 7 with 0 failures.
• What the 7 tests are:
  • guest_libc_internal_codecvt is the new guest test.
  • guest_locale holds the updated CodecvtUnshift assertion.
  • guest_err builds from the Err.cpp the stubs were removed from.
  • conventions_unknown_nids, conventions_debt_length, conventions_doc_links and debt_split are the repository's checker self-tests for the conventions and the debt-file split. They were run because the debt file changed.
• core/libs/tests/test_public_headers.py --audit-only (Windows): "406 libraries, 28350 exports: unique declarations and umbrella coverage verified".
• objdump -p on the Windows build: libSceLibcInternal.prx exports each of the nine <NID>_nid_no_patch_cut names once, and no Pending3_027..035 remains. libc.prx exports no _ZNKSt7codecvtIcc9_Mbstatet name; its only new symbol is the non-NID LibcCodecvtMethods_nid_no_patch.
• Negative control (Windows), with the rest of the branch and the new test unchanged: only main's CodecvtUnshift result (return 0;) is restored. guest_libc_internal_codecvt fails 1 of 1 with libc internal codecvt: do_unshift of codecvt<char, char> returns noconv, and guest_locale fails too. With return 3; back both pass.
• MSYS_NO_PATHCONV=1 python3 tools/check_conventions.py --base origin/main --title "<title>" --body <this body>: "All conventions checks passed."
• python3 tools/pr_overlap.py --branch feat/r2-codecvt-char exited 2 and printed "pr_overlap: overlap check failed closed; manually compare every reported PR branch before opening this one". It found no PR with the same exports or the same new files. It reported conflicting lines with feat(libSceLibcInternal): implement num_put<char>::put and time_put<char>::put #15715 only, and could not compare feat(aot): consolidate native ARM64 compiler, runtime and consumers #5021, fix(libs): share Sony CRT handler and lconv state between libc and libSceAmpr #7081, feat(libc): add std::__sce_v2::_Random_device, _Fiopen and setw #9526, feat(libc): export the messages facet vtable as data #10158, fix(libc): size the codecvt facet vtable to 104 bytes #10165, feat(libc): export the numpunct facet vtable as data #10200, feat(libc): export the time_put facet vtable as data #12510, feat(libc): export the money_get facet vtable as data #12511, feat(libc): export the money_put facet vtable as data #12518, feat(libc): export the wide time_put facet vtable as data #12704, fix(relinker): match AppContent utility import to provider #13486, feat(libSceLibcInternal): implement the msun trigonometric kernels #13778, feat(libSceLibcInternal): implement floating-point word access #13782, feat(libSceLibcInternal): implement _readdir_unlocked and _seekdir #13881, docs(debt): separate entries with blank lines and drop derived export totals #14212, feat(libSceLibcInternal): implement zero-return showmanyc exports #14401, feat(libSceLibcInternal): implement the placement operator delete and delete[] #14837 and feat(libSceLibcInternal): implement std::_MP_Add, _MP_Get, _MP_Mul and _MP_Rem #14936. I compared every one of them by hand, and also feat(libSceLibcInternal): implement the numpunct<char> members #14373 (numpunct<char>), feat(libSceLibcInternal): answer the codecvt and messages queries as firmware 13.42 does #15582 and feat(libSceLibcInternal): return from 52 empty facet members as firmware 13.42 does #15584 (other codecvt and facet members) and feat(libc): wire the codecvt<wchar_t,char> facet vtable #11172 (codecvt<wchar_t, char> vtable): for each I diffed the PR head against its merge base, searched the diff for the nine NIDs, the nine symbol names, the Pending3_027..035 stub names, Codecvt.cpp, CodecvtUnshift and LibcCodecvtMethods, and ran git merge-tree of the PR head against main and against this branch.
  • feat(libSceLibcInternal): implement num_put<char>::put and time_put<char>::put #15715 (num_put<char>::put and time_put<char>::put): no hits. It declares LibcTimePutPattern_nid_no_patch on the GuestLocale.hpp line where this PR declares LibcCodecvtMethods_nid_no_patch, which is a text conflict; whichever merges second keeps both lines.
  • feat(libc): wire the codecvt<wchar_t,char> facet vtable #11172: its only hit is its own WideCodecvtUnshift for the wide facet; it does not touch CodecvtUnshift and merges with this branch cleanly.
  • feat(libSceLibcInternal): implement the numpunct<char> members #14373, feat(libSceLibcInternal): answer the codecvt and messages queries as firmware 13.42 does #15582 and feat(libSceLibcInternal): return from 52 empty facet members as firmware 13.42 does #15584: no hits and no conflict with this branch.
  • feat(aot): consolidate native ARM64 compiler, runtime and consumers #5021, fix(libs): share Sony CRT handler and lconv state between libc and libSceAmpr #7081, feat(libc): add std::__sce_v2::_Random_device, _Fiopen and setw #9526, feat(libc): export the messages facet vtable as data #10158, fix(libc): size the codecvt facet vtable to 104 bytes #10165, feat(libc): export the numpunct facet vtable as data #10200, feat(libc): export the time_put facet vtable as data #12510, feat(libc): export the money_get facet vtable as data #12511, feat(libc): export the money_put facet vtable as data #12518, feat(libc): export the wide time_put facet vtable as data #12704, fix(relinker): match AppContent utility import to provider #13486, feat(libSceLibcInternal): implement the msun trigonometric kernels #13778, feat(libSceLibcInternal): implement floating-point word access #13782, feat(libSceLibcInternal): implement _readdir_unlocked and _seekdir #13881, docs(debt): separate entries with blank lines and drop derived export totals #14212, feat(libSceLibcInternal): implement zero-return showmanyc exports #14401, feat(libSceLibcInternal): implement the placement operator delete and delete[] #14837 and feat(libSceLibcInternal): implement std::_MP_Add, _MP_Get, _MP_Mul and _MP_Rem #14936: no hits. Each one's git merge-tree conflicts are the same against this branch as against main, so this branch adds none.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

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