feat(cc): function-pointer typedefs/params + positional struct initializers#492
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``typedef <ret> (*<alias>)(<args>);`` registers ``<alias>`` as a typedef-aliased spelling for the opaque ``"function_pointer"`` type cc.py already uses for local function-pointer variables and function-pointer parameters (b2ccf5d). The inner argument list is parsed and discarded — cc.py has no per-typedef callable machinery yet, so calling through a typedef'd function pointer still requires the local-variable shape; but the alias is enough for parameter types, return types, and casts, which is what ``<signal.h>`` and the ``<stdlib.h>`` qsort/bsearch/atexit prototypes need. Forcing function: ``user/libbboeos/include/signal.h`` declares ``typedef void (*sighandler_t)(int);`` and consumers use the alias as a parameter type, return type, and inside a cast (``#define SIG_DFL ((sighandler_t)0)``). Pre-patch, cc.py rejected the typedef with ``expected typedef alias name, got LPAREN``. Post-patch, the alias resolves through the existing ``typedef_aliases`` map and Cast is identity codegen for non-struct-pointer targets, so every use site Just Works. Phase 6 enablement: shrinks the libbboeos-on-cc.py gap by one header (``<signal.h>``) and removes a blocker for compiling ``user/libbboeos/stdlib.h`` and ``stdio.h`` prototypes that take callback function-pointer parameters. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
``struct T x = {a, b, c};`` is the positional form of brace
initialization — fields fill in declaration order, matching
standard C. Pre-patch, ``_parse_designated_struct_initializer``
hard-rejected any non-``.field``, non-``{0}`` shape; post-patch
it dispatches by leading token: ``DOT`` keeps the designated
path, anything else parses positional values into the existing
``StructInitializer.positional`` slot.
Codegen sides:
* Local struct VarDecl: ``_emit_struct_initializer`` already
zero-stores the slot then emits per-field MemberAssigns. The
positional branch zips field-name order from
``struct_layouts[tag]`` with the value list and reuses the
same MemberAssign synthesis.
* File-scope struct global: previously rejected because
``_constant_expression(StructInitializer)`` returns None. The
guard now lets brace initializers through for struct-typed
globals; a new ``_validate_struct_global_initializer`` checks
every field value is constant, and the global-emission loop
walks the layout to emit a width-appropriate directive per
field (``db``/``dw``/``dd`` matched to the field width).
Forcing function: ``user/libbboeos/stdio.c`` declares ``static
FILE _stderr = {0, 0, 2};`` on line 14. Phase 6 enablement —
``stdio.c`` now parses past line 14 (stops at line 451 on an
unrelated ``L`` identifier issue).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Summary
Two parser/codegen additions, each Phase 6 enablement for compiling
user/libbboeos/through cc.py.Function-pointer typedef aliases (Commit 1):
typedef <ret> (*<alias>)(<args>);registers<alias>as a typedef-aliasedspelling for the opaque
"function_pointer"type cc.py alreadyuses for local function-pointer variables and function-pointer
parameters (b2ccf5d). Unblocks
<signal.h>(sighandler_t)and the cast-based
SIG_DFL/SIG_IGNmacros, plus the<stdlib.h>qsort/bsearch/atexit prototypes that use namedcallback typedefs.
Positional struct initializers (Commit 2):
struct T x = {a, b, c};is the positional form of brace initialization — fieldsfill in declaration order. Pre-patch, cc.py only accepted
{0}zero-init and the designated
{.field = expr, ...}form.Codegen extended on both sides: local VarDecl reuses the existing
zero-store + per-field MemberAssign path; file-scope struct
globals now emit per-field directives walked from the struct
layout (
db/dw/ddmatched to field width). Forcingfunction:
user/libbboeos/stdio.cline 14 declaresstatic FILE _stderr = {0, 0, 2};.Test plan
python3 -m pytest tests/unit/ tests/test_ccobj.py tests/test_ccld.py tests/test_ccar.py -x -q— 559 passedpython3 tests/test_cc_bits.py— 112/112 passcc.py user/libbboeos/stdio.cparses past line 14(stops at line 451 on an unrelated identifier-as-label issue)
cc.py user/libbboeos/stdlib.cparses past theqsort/bsearch prototypes (the file's remaining blocker is
static void (*_atexit_fns[N])(void);— an array offunction pointers at file scope, not covered by this PR)
cc.py user/libbboeos/signal.cstill hits the pre-existingstringify-operator (
#x) limitation in the preprocessor at<syscalls.h>; the typedef/cast/parameter parse cleanly inisolation, confirmed via direct
signal.hprobes./make_os.sh— full image build succeedstimeout 240 python3 tests/test_asm.py— 42 passed, 0 failed🤖 Generated with Claude Code