perf(lsp): collapse repeated Python scope-chain lookups

Add cbm_scope_lookup_binding so callers can read lexical presence, type, and callable identity in one traversal. Route Python expression, call, and callable-reference resolution through that complete binding and use the existing checked bind APIs for allocation-failure detection.

The neutral 11-pair production matrix kept exact output parity. Python scale latency was 4.33% below merge parent 07255cfe and 61.01% below upstream parent 0c64de93; incremental instructions were 3.09% and 54.07% lower. Focused ASan/UBSan scope and Python suites passed 33 and 125 tests.

Signed-off-by: Andrew Hundt <ATHundt@gmail.com>

internal/cbm/lsp/py_lsp.c

@@ -193,20 +193,15 @@ static void py_disable_callable_value_proof(PyLSPContext *ctx) {
 
 static void py_scope_bind(PyLSPContext *ctx, const char *name, const CBMType *type) {
     ctx->type_cache_gen++;
-    cbm_scope_bind(ctx->current_scope, name, type);
-    if (name && !cbm_scope_contains(ctx->current_scope, name))
+    if (!cbm_scope_bind_checked(ctx->current_scope, name, type))
         py_disable_callable_value_proof(ctx);
 }
 
 static void py_scope_bind_callable(PyLSPContext *ctx, const char *name, const CBMType *type,
                                    const char *callable_qn) {
     ctx->type_cache_gen++;
-    cbm_scope_bind_callable(ctx->current_scope, name, type, callable_qn);
-    const char *bound = name ? cbm_scope_lookup_callable(ctx->current_scope, name) : NULL;
-    if (name && (!cbm_scope_contains(ctx->current_scope, name) ||
-                 (callable_qn && (!bound || strcmp(bound, callable_qn) != 0)))) {
+    if (!cbm_scope_bind_callable_checked(ctx->current_scope, name, type, callable_qn))
         py_disable_callable_value_proof(ctx);
-    }
 }
 
 static CBMScope *py_scope_push_checked(PyLSPContext *ctx) {
@@ -945,8 +940,9 @@ static const char *py_exact_callable_target_ex(PyLSPContext *ctx, TSNode node,
         char *name = py_node_text(ctx, node);
         if (!name)
             return NULL;
-        if (cbm_scope_contains(ctx->current_scope, name)) {
-            const char *bound = cbm_scope_lookup_callable(ctx->current_scope, name);
+        const CBMVarBinding *binding = cbm_scope_lookup_binding(ctx->current_scope, name);
+        if (binding) {
+            const char *bound = binding->callable_qn;
             if (bound && lexical_alias_out) {
                 /* A lexical binding that does NOT simply name the module symbol
                  * of the same spelling is an alias introduced in this body. Only
@@ -1025,12 +1021,13 @@ static void py_resolve_value_references_at(PyLSPContext *ctx, TSNode call) {
         const char *candidate = strcmp(kind, "identifier") == 0
                                     ? py_exact_imported_reference_candidate(ctx, source_name)
                                     : NULL;
-        if (candidate && cbm_scope_contains(ctx->current_scope, source_name)) {
-            const CBMType *binding =
-                cbm_type_resolve_alias(cbm_scope_lookup(ctx->current_scope, source_name));
-            if (binding && binding->kind == CBM_TYPE_NAMED &&
-                binding->data.named.qualified_name &&
-                strcmp(binding->data.named.qualified_name, candidate) == 0) {
+        const CBMVarBinding *scope_binding =
+            candidate ? cbm_scope_lookup_binding(ctx->current_scope, source_name) : NULL;
+        if (scope_binding) {
+            const CBMType *type = cbm_type_resolve_alias(scope_binding->type);
+            if (type && type->kind == CBM_TYPE_NAMED &&
+                type->data.named.qualified_name &&
+                strcmp(type->data.named.qualified_name, candidate) == 0) {
                 py_emit_unresolved_reference(ctx, candidate, arg);
             }
         }
@@ -1512,9 +1509,9 @@ static const CBMType *py_eval_expr_type_uncached(PyLSPContext *ctx, TSNode node)
         char *name = py_node_text(ctx, node);
         if (!name)
             return cbm_type_unknown();
-        const CBMType *t = cbm_scope_lookup(ctx->current_scope, name);
-        if (cbm_scope_contains(ctx->current_scope, name))
-            return t ? t : cbm_type_unknown();
+        const CBMVarBinding *binding = cbm_scope_lookup_binding(ctx->current_scope, name);
+        if (binding)
+            return binding->type ? binding->type : cbm_type_unknown();
         // Builtin globals: True / False / None at top level.
         if (strcmp(name, "True") == 0 || strcmp(name, "False") == 0)
             return cbm_type_builtin(ctx->arena, "bool");
@@ -1780,8 +1777,11 @@ static const CBMType *py_eval_expr_type_uncached(PyLSPContext *ctx, TSNode node)
                 }
             }
             // Constructor call: ClassName() returns NAMED(ClassName).
-            const CBMType *in_scope = cbm_scope_lookup(ctx->current_scope, fname);
-            const char *callable_qn = cbm_scope_lookup_callable(ctx->current_scope, fname);
+            const CBMVarBinding *binding =
+                cbm_scope_lookup_binding(ctx->current_scope, fname);
+            const CBMType *in_scope =
+                binding && binding->type ? binding->type : cbm_type_unknown();
+            const char *callable_qn = binding ? binding->callable_qn : NULL;
             if (callable_qn) {
                 return py_func_return_type(ctx, callable_qn);
             }
@@ -1809,7 +1809,7 @@ static const CBMType *py_eval_expr_type_uncached(PyLSPContext *ctx, TSNode node)
             }
             /* Even an UNKNOWN local/parameter is a real lexical shadow. Do
              * not borrow the return type of a same-named module function. */
-            if (cbm_scope_contains(ctx->current_scope, fname))
+            if (binding)
                 return cbm_type_unknown();
             // Module-local function call.
             const CBMRegisteredFunc *f =
@@ -2579,14 +2579,16 @@ static void py_emit_call_for(PyLSPContext *ctx, TSNode call_node) {
          * An ordinary local binding is also a hard shadow: if it is not a
          * proven callable alias, do not fall through and fabricate a direct
          * call to a module-level function with the same spelling. */
-        if (cbm_scope_contains(ctx->current_scope, fname)) {
-            const char *alias_target = cbm_scope_lookup_callable(ctx->current_scope, fname);
+        const CBMVarBinding *binding = cbm_scope_lookup_binding(ctx->current_scope, fname);
+        if (binding) {
+            const char *alias_target = binding->callable_qn;
             if (alias_target) {
                 py_emit_resolved_call_reason(ctx, alias_target, "lsp_callable_alias", 0.97f, fname,
                                              call_node);
                 return;
             }
-            const CBMType *in_scope = cbm_scope_lookup(ctx->current_scope, fname);
+            const CBMType *in_scope =
+                binding->type ? binding->type : cbm_type_unknown();
             if (!cbm_type_is_unknown(in_scope) && in_scope->kind == CBM_TYPE_NAMED) {
                 const char *qn = in_scope->data.named.qualified_name;
                 const char *tail = qn ? strrchr(qn, '.') : NULL;
@@ -2618,13 +2620,6 @@ static void py_emit_call_for(PyLSPContext *ctx, TSNode call_node) {
             }
             return;
         }
-        // Constructor call (ClassName())
-        const CBMType *in_scope = cbm_scope_lookup(ctx->current_scope, fname);
-        if (!cbm_type_is_unknown(in_scope) && in_scope->kind == CBM_TYPE_NAMED) {
-            const char *qn = in_scope->data.named.qualified_name;
-            py_emit_resolved_call(ctx, qn, "lsp_constructor", 0.85f, call_node);
-            return;
-        }
         // Module-local function
         const CBMRegisteredFunc *f =
             cbm_registry_lookup_symbol(ctx->registry, ctx->module_qn, fname);

internal/cbm/lsp/scope.c

@@ -88,54 +88,36 @@ bool cbm_scope_bind_callable_checked(CBMScope *scope, const char *name, const CB
     return cbm_scope_bind_value(scope, name, type, callable_qn);
 }
 
-const CBMType* cbm_scope_lookup(const CBMScope* scope, const char* name) {
-    if (!name) {
-        return cbm_type_unknown();
-    }
-    for (const CBMScope* s = scope; s != NULL; s = s->parent) {
-        for (CBMScopeChunk* c = s->chunks; c != NULL; c = c->next) {
-            for (int i = 0; i < c->used; i++) {
-                if (c->bindings[i].name && strcmp(c->bindings[i].name, name) == 0) {
-                    return c->bindings[i].type;
-                }
-            }
-        }
-    }
-    return cbm_type_unknown();
-}
-
-bool cbm_scope_contains(const CBMScope *scope, const char *name) {
-    if (!name) {
-        return false;
-    }
-    for (const CBMScope *s = scope; s != NULL; s = s->parent) {
-        for (const CBMScopeChunk *c = s->chunks; c != NULL; c = c->next) {
-            for (int i = 0; i < c->used; i++) {
-                if (c->bindings[i].name && strcmp(c->bindings[i].name, name) == 0) {
-                    return true;
-                }
-            }
-        }
-    }
-    return false;
-}
-
-const char *cbm_scope_lookup_callable(const CBMScope *scope, const char *name) {
-    if (!name) {
+const CBMVarBinding *cbm_scope_lookup_binding(const CBMScope *scope, const char *name) {
+    if (!name)
         return NULL;
-    }
-    for (const CBMScope *s = scope; s != NULL; s = s->parent) {
-        for (const CBMScopeChunk *c = s->chunks; c != NULL; c = c->next) {
+    for (const CBMScope* s = scope; s != NULL; s = s->parent) {
+        for (const CBMScopeChunk* c = s->chunks; c != NULL; c = c->next) {
             for (int i = 0; i < c->used; i++) {
-                if (c->bindings[i].name && strcmp(c->bindings[i].name, name) == 0) {
-                    return c->bindings[i].callable_qn;
-                }
+                if (c->bindings[i].name && strcmp(c->bindings[i].name, name) == 0)
+                    return &c->bindings[i];
             }
         }
     }
     return NULL;
 }
 
+const CBMType* cbm_scope_lookup(const CBMScope* scope, const char* name) {
+    const CBMVarBinding *binding = cbm_scope_lookup_binding(scope, name);
+    if (binding)
+        return binding->type;
+    return cbm_type_unknown();
+}
+
+bool cbm_scope_contains(const CBMScope *scope, const char *name) {
+    return cbm_scope_lookup_binding(scope, name) != NULL;
+}
+
+const char *cbm_scope_lookup_callable(const CBMScope *scope, const char *name) {
+    const CBMVarBinding *binding = cbm_scope_lookup_binding(scope, name);
+    return binding ? binding->callable_qn : NULL;
+}
+
 bool cbm_scope_update_callable(CBMScope *scope, const char *name, const char *callable_qn) {
     if (!name) {
         return false;

internal/cbm/lsp/scope.h

@@ -82,6 +82,10 @@ bool cbm_scope_bind_callable_checked(CBMScope *scope, const char *name, const CB
 void cbm_scope_bind_callable(CBMScope *scope, const char *name, const CBMType *type,
                              const char *callable_qn);
 const CBMType* cbm_scope_lookup(const CBMScope* scope, const char* name);
+/* Return the complete nearest binding in one scope-chain walk, or NULL when
+ * unbound. Callers that need presence, type, and callable identity together
+ * should use this instead of repeating three linear scans. */
+const CBMVarBinding *cbm_scope_lookup_binding(const CBMScope *scope, const char *name);
 /* True when any lexical frame contains name, even when its type is UNKNOWN. */
 bool cbm_scope_contains(const CBMScope *scope, const char *name);
 /* Return the exact callable QN from the nearest binding.  A nearer ordinary

tests/test_scope.c

@@ -125,6 +125,25 @@ TEST(scope_callable_identity_follows_nearest_binding) {
     PASS();
 }
 
+TEST(scope_lookup_binding_returns_nearest_complete_record) {
+    CBMArena a;
+    cbm_arena_init(&a);
+    CBMScope *root = cbm_scope_push(&a, NULL);
+    CBMScope *child = cbm_scope_push(&a, root);
+    cbm_scope_bind_callable(root, "callback", named_t(&a, "Callback"), "pkg.actual");
+    cbm_scope_bind(child, "callback", named_t(&a, "Shadow"));
+
+    const CBMVarBinding *binding = cbm_scope_lookup_binding(child, "callback");
+    ASSERT_NOT_NULL(binding);
+    ASSERT_STR_EQ(binding->name, "callback");
+    ASSERT_STR_EQ(binding->type->data.named.qualified_name, "Shadow");
+    ASSERT_NULL(binding->callable_qn);
+    ASSERT_NULL(cbm_scope_lookup_binding(child, "missing"));
+
+    cbm_arena_destroy(&a);
+    PASS();
+}
+
 TEST(scope_assignment_updates_or_clears_nearest_callable_only) {
     CBMArena a;
     cbm_arena_init(&a);
@@ -260,6 +279,7 @@ SUITE(scope) {
     RUN_TEST(scope_lookup_walks_parent_chain);
     RUN_TEST(scope_child_shadows_parent);
     RUN_TEST(scope_callable_identity_follows_nearest_binding);
+    RUN_TEST(scope_lookup_binding_returns_nearest_complete_record);
     RUN_TEST(scope_assignment_updates_or_clears_nearest_callable_only);
     RUN_TEST(scope_checked_bind_reports_child_oom_despite_parent_name);
     RUN_TEST(scope_dynamic_growth_300_bindings);