Establish R0 compiler foundation

[igniting]

Establishes the R0 foundation for restoring the legacy Ada compiler: a reproducible modern host build, an honest analysis CLI, an executable grammar-coverage ledger, and a validated Linux MIPS/QEMU target contract.

Changes

• Replace root-level lex/yacc artifacts with strict C11 Flex/Bison builds under build/, plus an adac driver whose R0 check phase reports stable diagnostics and whose unavailable compile/build phases fail without artifacts.
• Remove parser-owned entry-point and symbol-table globals, preserve literal spelling, canonicalize identifiers safely, correct source positions, and modernize legacy utility/table code.
• Inventory all 233 nonterminals and 513 grammar alternatives, validate zero parser conflicts, classify the tracked corpus by release, and add drift/ambiguity regression tests.
• Pin the little-endian MIPS32r2/o32 hard-float toolchain contract and add freestanding startup/syscall/linker fixtures for text-only and writable-data ELF executables.
• Validate static ELF layout, plain qemu-mipsel execution, syscall behavior, and six-argument interoperability with mipsel-linux-gnu-gcc-13.

Testing

• PASS — make clean && make strict
• PASS — make strict (no repeated compile/link work; validation gates reran)
• PASS — make test
• PASS — python3 -m unittest -v tests/unit/test_grammar_inventory.py (9 tests)
• PASS — python3 tests/run_tests.py --build-dir /tmp/adac-r0-evidence/contract

The contract runner passed text-only ELF/QEMU, writable-data ELF/QEMU, and six-argument cross-GCC ABI probes. The grammar baseline is 233 nonterminals, 513 alternatives, 0 shift/reduce conflicts, and 0 reduce/reduce conflicts.

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Session Details

• Session: View Session
• Requested by: Anshu Avinash (anshu.avinash@devrev.ai)
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