Perceus ARC backend (--memory=arc), osprey test line coverage, and standalone-file LSP diagnostics

Makefile

@@ -62,14 +62,21 @@ A    ?= -c -fPIC -O2 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -Werror -Wall
 B    ?= $(A) -std=c11
 OSSL ?= -DOPENSSL_SUPPRESS_DEPRECATED -DOPENSSL_API_COMPAT=30000 -Wno-deprecated-declarations
 # Object lists for the archives (paths relative to compiler/, where `ar` runs).
-FIB_OBJ  ?= bin/memory_runtime.o bin/fiber_runtime.o bin/system_runtime.o bin/effects_runtime.o bin/string_runtime.o bin/string_runtime_list.o bin/list_runtime.o bin/map_runtime.o bin/map_runtime_hamt.o bin/json_runtime.o bin/ffi_runtime.o bin/term_runtime.o bin/random_runtime.o bin/test_runtime.o bin/profiler_runtime.o bin/profiler_sampler.o
+FIB_OBJ  ?= bin/memory_runtime.o bin/fiber_runtime.o bin/system_runtime.o bin/effects_runtime.o bin/string_runtime.o bin/string_runtime_list.o bin/list_runtime.o bin/map_runtime.o bin/map_runtime_hamt.o bin/json_runtime.o bin/ffi_runtime.o bin/term_runtime.o bin/random_runtime.o bin/test_runtime.o bin/coverage_runtime.o bin/profiler_runtime.o bin/profiler_sampler.o
 HTTP_OBJ ?= bin/http_shared.o bin/http_client_runtime.o bin/http_server_request.o bin/http_server_response.o bin/http_server_runtime.o bin/websocket_client_runtime.o bin/websocket_server_runtime.o $(FIB_OBJ)
 # GC backend archives (osprey --memory=gc): the tracing collector replaces
 # memory_runtime.o, and the value-container units are rebuilt with the malloc
 # redirect (osp_gc_shim.h) so their nodes live in the managed heap. Everything
 # else is the same object. Implements [GC-TRACE-CONSERVATIVE], docs/plans/0011.
-FIB_OBJ_GC  ?= bin/memory_gc.o bin/fiber_runtime.o bin/system_runtime.o bin/effects_runtime.o bin/string_runtime.o bin/string_runtime_list.o bin/gc/list_runtime.o bin/gc/map_runtime.o bin/gc/map_runtime_hamt.o bin/json_runtime.o bin/ffi_runtime.o bin/term_runtime.o bin/random_runtime.o bin/test_runtime.o bin/profiler_runtime.o bin/profiler_sampler.o
+FIB_OBJ_GC  ?= bin/memory_gc.o bin/fiber_runtime.o bin/system_runtime.o bin/effects_runtime.o bin/string_runtime.o bin/string_runtime_list.o bin/gc/list_runtime.o bin/gc/map_runtime.o bin/gc/map_runtime_hamt.o bin/json_runtime.o bin/ffi_runtime.o bin/term_runtime.o bin/random_runtime.o bin/test_runtime.o bin/coverage_runtime.o bin/profiler_runtime.o bin/profiler_sampler.o
 HTTP_OBJ_GC ?= bin/http_shared.o bin/http_client_runtime.o bin/http_server_request.o bin/http_server_response.o bin/http_server_runtime.o bin/websocket_client_runtime.o bin/websocket_server_runtime.o $(FIB_OBJ_GC)
+# ARC backend archives (osprey --memory=arc): Perceus reference counting
+# replaces memory_runtime.o, and the value-producing units (containers +
+# strings + JSON) are rebuilt with the allocation redirect (osp_arc_shim.h) so
+# their nodes/buffers carry the 16-byte header and registry entry. Implements
+# [GC-ARC-PERCEUS], docs/plans/0011 phase 2 (milestone M1).
+FIB_OBJ_ARC  ?= bin/memory_arc.o bin/fiber_runtime.o bin/system_runtime.o bin/effects_runtime.o bin/arc/string_runtime.o bin/arc/string_runtime_list.o bin/arc/list_runtime.o bin/arc/map_runtime.o bin/arc/map_runtime_hamt.o bin/arc/json_runtime.o bin/ffi_runtime.o bin/term_runtime.o bin/random_runtime.o bin/test_runtime.o bin/coverage_runtime.o bin/profiler_runtime.o bin/profiler_sampler.o
+HTTP_OBJ_ARC ?= bin/http_shared.o bin/http_client_runtime.o bin/http_server_request.o bin/http_server_response.o bin/http_server_runtime.o bin/websocket_client_runtime.o bin/websocket_server_runtime.o $(FIB_OBJ_ARC)
 
 # WebAssembly (wasm32-wasip1) cross-build toolchain — opt-in via `make wasm`.
 # Compiles the portable C-runtime subset (no pthreads/sockets/OpenSSL/syscalls)
@@ -94,7 +101,7 @@ WASM_CFLAGS  ?= --target=$(WASM_TARGET) --sysroot=$(WASI_SYSROOT) -O2 -std=c11 -
 # (termios) and ffi (dlopen).
 # profiler_runtime compiles to inert stubs on wasm32 (no pthreads/signals) but
 # must be present: codegen anchors `osp_prof_boot` into every main [PROF-ACTIVATE-ENV].
-WASM_RT_SRC  ?= memory_runtime string_runtime string_runtime_list list_runtime map_runtime map_runtime_hamt json_runtime effects_runtime test_runtime web_runtime profiler_runtime
+WASM_RT_SRC  ?= memory_runtime string_runtime string_runtime_list list_runtime map_runtime map_runtime_hamt json_runtime effects_runtime test_runtime coverage_runtime web_runtime profiler_runtime
 # `make wasm-serve` static-host dir + port for the in-browser example.
 WASM_SERVE_DIR  ?= examples/wasm
 WASM_SERVE_PORT ?= 8080
@@ -275,12 +282,19 @@ setup:
 # so `cd` persists; faithful port of the original hardened C recipes.
 _runtime:
 	@echo "==> building C runtime archives ($(RTB)/lib*_runtime.a)"
-	@cd compiler && set -e && $(MKDIR) bin lib bin/gc && \
+	@cd compiler && set -e && $(MKDIR) bin lib bin/gc bin/arc && \
 	  $(CC) $(B) runtime/memory_runtime.c       -o bin/memory_runtime.o && \
 	  $(CC) $(B) runtime/memory_gc.c            -o bin/memory_gc.o && \
+	  $(CC) $(B) runtime/memory_arc.c           -o bin/memory_arc.o && \
 	  $(CC) $(B) -include runtime/osp_gc_shim.h runtime/list_runtime.c     -o bin/gc/list_runtime.o && \
 	  $(CC) $(B) -include runtime/osp_gc_shim.h runtime/map_runtime.c      -o bin/gc/map_runtime.o && \
 	  $(CC) $(B) -include runtime/osp_gc_shim.h runtime/map_runtime_hamt.c -o bin/gc/map_runtime_hamt.o && \
+	  $(CC) $(B) -include runtime/osp_arc_shim.h runtime/list_runtime.c        -o bin/arc/list_runtime.o && \
+	  $(CC) $(B) -include runtime/osp_arc_shim.h runtime/map_runtime.c         -o bin/arc/map_runtime.o && \
+	  $(CC) $(B) -include runtime/osp_arc_shim.h runtime/map_runtime_hamt.c    -o bin/arc/map_runtime_hamt.o && \
+	  $(CC) $(A) -include runtime/osp_arc_shim.h runtime/string_runtime.c      -o bin/arc/string_runtime.o && \
+	  $(CC) $(A) -include runtime/osp_arc_shim.h runtime/string_runtime_list.c -o bin/arc/string_runtime_list.o && \
+	  $(CC) $(B) -include runtime/osp_arc_shim.h runtime/json_runtime.c        -o bin/arc/json_runtime.o && \
 	  $(CC) -c -fPIC -O2 -Werror -Wall -Wextra -Wpedantic -std=c11 -D_GNU_SOURCE runtime/fiber_runtime.c -o bin/fiber_runtime.o && \
 	  $(CC) $(A) runtime/system_runtime.c       -o bin/system_runtime.o && \
 	  $(CC) $(A) runtime/effects_runtime.c      -o bin/effects_runtime.o && \
@@ -294,6 +308,7 @@ _runtime:
 	  $(CC) $(B) runtime/term_runtime.c         -o bin/term_runtime.o && \
 	  $(CC) $(B) runtime/random_runtime.c       -o bin/random_runtime.o && \
 	  $(CC) $(B) runtime/test_runtime.c         -o bin/test_runtime.o && \
+	  $(CC) $(B) runtime/coverage_runtime.c     -o bin/coverage_runtime.o && \
 	  $(CC) $(B) runtime/profiler_runtime.c     -o bin/profiler_runtime.o && \
 	  $(CC) $(B) runtime/profiler_sampler.c     -o bin/profiler_sampler.o && \
 	  $(CC) -c -fPIC -O2 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -Werror -Wall -Wextra \
@@ -312,7 +327,9 @@ _runtime:
 	  $(AR) rcs bin/libhttp_runtime.a  $(HTTP_OBJ) && \
 	  $(AR) rcs bin/libfiber_runtime_gc.a $(FIB_OBJ_GC) && \
 	  $(AR) rcs bin/libhttp_runtime_gc.a  $(HTTP_OBJ_GC) && \
-	  cp bin/libfiber_runtime.a bin/libhttp_runtime.a bin/libfiber_runtime_gc.a bin/libhttp_runtime_gc.a lib/
+	  $(AR) rcs bin/libfiber_runtime_arc.a $(FIB_OBJ_ARC) && \
+	  $(AR) rcs bin/libhttp_runtime_arc.a  $(HTTP_OBJ_ARC) && \
+	  cp bin/libfiber_runtime.a bin/libhttp_runtime.a bin/libfiber_runtime_gc.a bin/libhttp_runtime_gc.a bin/libfiber_runtime_arc.a bin/libhttp_runtime_arc.a lib/
 
 # Cross-compile the portable C-runtime subset to a wasm32-wasip1 archive that
 # osprey links for `--target=wasm32`. One shell so `cd` persists. Fails loudly
@@ -388,7 +405,11 @@ _test_c_runtime:
 	  $(CC) -O2 -g -fno-omit-frame-pointer -D_FORTIFY_SOURCE=2 -fstack-protector-strong -Werror -Wall -Wextra \
 	  -ftrapv -std=c11 -D_GNU_SOURCE \
 	  runtime/profiler_runtime_tests.c runtime/profiler_runtime.c runtime/profiler_sampler.c -pthread \
-	  -o bin/profiler_runtime_tests && ./bin/profiler_runtime_tests
+	  -o bin/profiler_runtime_tests && ./bin/profiler_runtime_tests && \
+	  $(CC) -O2 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -Werror -Wall -Wextra \
+	  -ftrapv -std=c11 -D_GNU_SOURCE \
+	  runtime/coverage_runtime_tests.c runtime/coverage_runtime.c \
+	  -o bin/coverage_runtime_tests && ./bin/coverage_runtime_tests
 
 # [PROF-TEST] end-to-end profiler gate: --profile runs, exports, and reports.
 _test_profiler:
@@ -413,6 +434,14 @@ _conformance-gc: build
 	@out=$$(OSPREY_RUN_FLAGS=--memory=gc zsh crates/diff_examples.sh); echo "$$out"; \
 	  echo "$$out" | grep -Eq 'FAIL=0 ' || { echo 'FAIL: GC backend output diverged'; exit 1; }
 
+# _conformance-arc: run every tested example under the Perceus ARC backend;
+# output must be byte-identical to the default ([MEM-BACKENDS] / [GC-ARC-PERCEUS],
+# docs/plans/0011 phase 2).
+_conformance-arc: build
+	@echo "==> [conformance] differential harness under --memory=arc..."
+	@out=$$(OSPREY_RUN_FLAGS=--memory=arc zsh crates/diff_examples.sh); echo "$$out"; \
+	  echo "$$out" | grep -Eq 'FAIL=0 ' || { echo 'FAIL: ARC backend output diverged'; exit 1; }
+
 # --- vscode-extension -------------------------------------------------------
 # The extension's LSP server spawns the `osprey` binary at runtime, so the
 # integration tests need a real compiler on PATH: the Rust binary is staged as

benchmarks/cases/ackermann/ackermann.cs

@@ -0,0 +1,13 @@
+// Ackermann–Péter function — deep, non-tail mutual self-recursion.
+
+System.Console.WriteLine(Ack(3, 10));
+
+static long Add(long a, long b) => a + b;
+static long Sub(long a, long b) => a - b;
+
+static long Ack(long m, long n)
+{
+    if (m == 0) return Add(n, 1);
+    if (n == 0) return Ack(Sub(m, 1), 1);
+    return Ack(Sub(m, 1), Ack(m, Sub(n, 1)));
+}

benchmarks/cases/ackermann/ackermann.dart

@@ -0,0 +1,14 @@
+// Ackermann–Péter function — deep, non-tail mutual self-recursion.
+
+int add(int a, int b) => a + b;
+int sub(int a, int b) => a - b;
+
+int ack(int m, int n) {
+  if (m == 0) return add(n, 1);
+  if (n == 0) return ack(sub(m, 1), 1);
+  return ack(sub(m, 1), ack(m, sub(n, 1)));
+}
+
+void main() {
+  print(ack(3, 10));
+}

benchmarks/cases/binarytrees/binarytrees.cs

@@ -0,0 +1,32 @@
+// Allocate + traverse many short-lived binary trees — allocation/memory stress: build 1200 trees of depth 13, sum checks.
+
+long acc = 0;
+for (long i = 0; i < 1200; i++)
+{
+    Tree t = Make(13);
+    acc += Check(t);
+}
+System.Console.WriteLine(acc);
+
+static Tree Make(long d)
+{
+    Tree t = new Tree();
+    if (d != 0)
+    {
+        t.Left = Make(d - 1);
+        t.Right = Make(d - 1);
+    }
+    return t;
+}
+
+static long Check(Tree t)
+{
+    if (t == null) return 0;
+    return 1 + Check(t.Left) + Check(t.Right);
+}
+
+class Tree
+{
+    public Tree Left;
+    public Tree Right;
+}

benchmarks/cases/binarytrees/binarytrees.dart

@@ -0,0 +1,29 @@
+// Allocate + traverse many short-lived binary trees — allocation/memory stress: build 1200 trees of depth 13, sum checks.
+
+class Tree {
+  Tree? left;
+  Tree? right;
+}
+
+Tree make(int d) {
+  final t = Tree();
+  if (d != 0) {
+    t.left = make(d - 1);
+    t.right = make(d - 1);
+  }
+  return t;
+}
+
+int check(Tree? t) {
+  if (t == null) return 0;
+  return 1 + check(t.left) + check(t.right);
+}
+
+void main() {
+  int acc = 0;
+  for (int i = 0; i < 1200; i++) {
+    final t = make(13);
+    acc += check(t);
+  }
+  print(acc);
+}

benchmarks/cases/coins/coins.cs

@@ -0,0 +1,20 @@
+// Coin-change ways count — branching recursion over coin kinds.
+
+System.Console.WriteLine(Ways(600, 5));
+
+static long Coin(long k) => k switch
+{
+    1 => 1,
+    2 => 5,
+    3 => 10,
+    4 => 25,
+    _ => 50,
+};
+
+static long Ways(long amount, long kind)
+{
+    if (amount == 0) return 1;
+    if (amount < 0) return 0;
+    if (kind == 0) return 0;
+    return Ways(amount - Coin(kind), kind) + Ways(amount, kind - 1);
+}

benchmarks/cases/coins/coins.dart

@@ -0,0 +1,27 @@
+// Coin-change ways count — branching recursion over coin kinds.
+
+int coin(int k) {
+  switch (k) {
+    case 1:
+      return 1;
+    case 2:
+      return 5;
+    case 3:
+      return 10;
+    case 4:
+      return 25;
+    default:
+      return 50;
+  }
+}
+
+int ways(int amount, int kind) {
+  if (amount == 0) return 1;
+  if (amount < 0) return 0;
+  if (kind == 0) return 0;
+  return ways(amount - coin(kind), kind) + ways(amount, kind - 1);
+}
+
+void main() {
+  print(ways(600, 5));
+}

benchmarks/cases/collatz/collatz.cs

@@ -0,0 +1,11 @@
+// Collatz (3n+1) stopping time summed over 1..N — integer division (n/2) in deep recursion.
+
+long acc = 0;
+for (long i = 1; i < 100001; i++) acc += Collatz(i);
+System.Console.WriteLine(acc);
+
+static long Collatz(long n)
+{
+    if (n == 1) return 0;
+    return n % 2 == 0 ? 1 + Collatz(n / 2) : 1 + Collatz(3 * n + 1);
+}

benchmarks/cases/collatz/collatz.dart

@@ -0,0 +1,14 @@
+// Collatz (3n+1) stopping time summed over 1..N — integer division (n/2) in deep recursion.
+
+int collatz(int n) {
+  if (n == 1) return 0;
+  return n % 2 == 0 ? 1 + collatz(n ~/ 2) : 1 + collatz(3 * n + 1);
+}
+
+void main() {
+  int acc = 0;
+  for (int i = 1; i < 100001; i++) {
+    acc += collatz(i);
+  }
+  print(acc);
+}

benchmarks/cases/coprime/coprime.cs

@@ -0,0 +1,14 @@
+// Count coprime pairs (i,j), 1<=i,j<=N — nested iteration + Euclidean gcd.
+
+long n = 2000;
+long acc = 0;
+for (long i = n; i > 0; i--)
+{
+    for (long j = n; j > 0; j--)
+    {
+        if (Gcd(i, j) == 1) acc++;
+    }
+}
+System.Console.WriteLine(acc);
+
+static long Gcd(long a, long b) => b == 0 ? a : Gcd(b, a % b);

benchmarks/cases/coprime/coprime.dart

@@ -0,0 +1,16 @@
+// Count coprime pairs (i,j), 1<=i,j<=N — nested iteration + Euclidean gcd.
+
+int gcd(int a, int b) => b == 0 ? a : gcd(b, a % b);
+
+void main() {
+  const n = 2000;
+  int acc = 0;
+  for (int i = n; i > 0; i--) {
+    for (int j = n; j > 0; j--) {
+      if (gcd(i, j) == 1) {
+        acc++;
+      }
+    }
+  }
+  print(acc);
+}

benchmarks/cases/digitsum/digitsum.cs

@@ -0,0 +1,7 @@
+// Sum of decimal digit-sums over 1..N — integer division (n/10) and modulo in recursion.
+
+long acc = 0;
+for (long i = 1; i < 2000001; i++) acc += DigSum(i);
+System.Console.WriteLine(acc);
+
+static long DigSum(long n) => n < 10 ? n : (n % 10) + DigSum(n / 10);

benchmarks/cases/digitsum/digitsum.dart

@@ -0,0 +1,11 @@
+// Sum of decimal digit-sums over 1..N — integer division (n/10) and modulo in recursion.
+
+int digsum(int n) => n < 10 ? n : (n % 10) + digsum(n ~/ 10);
+
+void main() {
+  int acc = 0;
+  for (int i = 1; i < 2000001; i++) {
+    acc += digsum(i);
+  }
+  print(acc);
+}