implement M6 ownership core

fec/src/own.c

@@ -1,4 +1,21 @@
 #include "own.h"
+#include <string.h>
+
+static FeLoc fe_own_no_loc(void)
+{
+    FeLoc loc;
+    loc.file = 0;
+    loc.line = 0;
+    loc.col = 0;
+    return loc;
+}
+
+static void fe_own_error_note(FeDiags *diags, FeLoc loc, const char *msg,
+                              FeLoc note, const char *note_msg)
+{
+    fe_diag_error(diags, loc, msg);
+    if (note.file) fe_diag_note_src(diags, note, note_msg);
+}
 
 int fe_own_is_copy_type(FeType *type)
 {
@@ -25,6 +42,380 @@ int fe_own_is_copy_type(FeType *type)
     return 1;
 }
 
+int fe_own_is_reference_like(FeType *type)
+{
+    return type && (type->kind == FE_TYPE_REF ||
+                    type->kind == FE_TYPE_SLICE ||
+                    type->kind == FE_TYPE_STR);
+}
+
+static FeNode *fe_own_root_expr(FeNode *expr)
+{
+    if (!expr) return 0;
+    if (expr->kind == FE_N_IDENT) return expr;
+    if (expr->kind == FE_N_MEMBER || expr->kind == FE_N_INDEX)
+        return fe_own_root_expr(expr->a);
+    if (expr->kind == FE_N_UNARY && expr->text &&
+        (strcmp(expr->text, "&") == 0 || strcmp(expr->text, "&mut") == 0))
+        return fe_own_root_expr(expr->a);
+    return 0;
+}
+
+int fe_own_place_from_expr(FeNode *expr, FeOwnPlace *place)
+{
+    FeNode *root;
+    if (!place) return 0;
+    place->root = 0;
+    place->root_cname = 0;
+    place->projected = 0;
+    root = fe_own_root_expr(expr);
+    if (!root) return 0;
+    place->root = root;
+    place->root_cname = root->cname ? root->cname : root->text;
+    place->projected = root != expr;
+    return place->root_cname != 0;
+}
+
+void fe_own_state_init(FeOwnState *state, int initialized)
+{
+    if (!state) return;
+    state->move = FE_OWN_AVAILABLE;
+    state->initialized = initialized != 0;
+    state->shared = 0;
+    state->exclusive = 0;
+    state->borrow_conflict = 0;
+    state->move_loc = fe_own_no_loc();
+    state->borrow_loc = fe_own_no_loc();
+}
+
+static int fe_own_require_value(FeDiags *diags, FeOwnState *state, FeLoc loc)
+{
+    if (!state->initialized) {
+        fe_diag_error(diags, loc, "use of uninitialized variable");
+        return 0;
+    }
+    if (state->move == FE_OWN_MOVED) {
+        fe_own_error_note(diags, loc, "use of moved value", state->move_loc,
+                          "value was moved here");
+        return 0;
+    }
+    if (state->move == FE_OWN_MAYBE_MOVED) {
+        fe_diag_error(diags, loc, "use of possibly moved value");
+        return 0;
+    }
+    return 1;
+}
+
+static int fe_own_require_stable_borrow(FeDiags *diags, FeOwnState *state,
+                                        FeLoc loc)
+{
+    if (!state->borrow_conflict) return 1;
+    fe_own_error_note(diags, loc,
+        "incompatible borrow state across control-flow paths",
+        state->borrow_loc, "borrow originated here");
+    return 0;
+}
+
+int fe_own_access(FeDiags *diags, FeOwnState *state,
+                  FeOwnAccessKind access, FeLoc loc)
+{
+    if (!state) return 0;
+    if (access == FE_OWN_PROJECTION) return 1;
+
+    if (!fe_own_require_stable_borrow(diags, state, loc)) return 0;
+
+    if (access == FE_OWN_WRITE) {
+        if (state->shared || state->exclusive) {
+            fe_own_error_note(diags, loc, "cannot write while value is borrowed",
+                              state->borrow_loc, "borrow originated here");
+            return 0;
+        }
+        state->move = FE_OWN_AVAILABLE;
+        state->initialized = 1;
+        state->move_loc = fe_own_no_loc();
+        return 1;
+    }
+
+    if (!fe_own_require_value(diags, state, loc)) return 0;
+
+    switch (access) {
+    case FE_OWN_READ:
+        if (state->exclusive) {
+            fe_own_error_note(diags, loc,
+                "cannot read directly while value is mutably borrowed",
+                state->borrow_loc, "mutable borrow originated here");
+            return 0;
+        }
+        return 1;
+    case FE_OWN_MOVE:
+        if (state->shared || state->exclusive) {
+            fe_own_error_note(diags, loc, "cannot move while value is borrowed",
+                              state->borrow_loc, "borrow originated here");
+            return 0;
+        }
+        state->move = FE_OWN_MOVED;
+        state->initialized = 0;
+        state->move_loc = loc;
+        return 1;
+    case FE_OWN_BORROW_SHARED:
+        if (state->exclusive) {
+            fe_own_error_note(diags, loc,
+                "cannot create shared borrow while mutable borrow is live",
+                state->borrow_loc, "mutable borrow originated here");
+            return 0;
+        }
+        if (!state->shared) state->borrow_loc = loc;
+        ++state->shared;
+        return 1;
+    case FE_OWN_BORROW_MUT:
+        if (state->shared || state->exclusive) {
+            fe_own_error_note(diags, loc,
+                "cannot create mutable borrow while another borrow is live",
+                state->borrow_loc, "existing borrow originated here");
+            return 0;
+        }
+        state->exclusive = 1;
+        state->borrow_loc = loc;
+        return 1;
+    default:
+        break;
+    }
+    return 1;
+}
+
+void fe_own_release_shared(FeOwnState *state)
+{
+    if (!state || !state->shared) return;
+    --state->shared;
+    if (!state->shared && !state->exclusive)
+        state->borrow_loc = fe_own_no_loc();
+}
+
+void fe_own_release_exclusive(FeOwnState *state)
+{
+    if (!state) return;
+    state->exclusive = 0;
+    if (!state->shared) state->borrow_loc = fe_own_no_loc();
+}
+
+FeOwnState fe_own_merge_state(FeOwnState left, FeOwnState right)
+{
+    FeOwnState out;
+    out.move = left.move == right.move ? left.move :
+        fe_own_merge_move(left.move, right.move);
+    out.initialized = left.initialized && right.initialized;
+    out.shared = left.shared > right.shared ? left.shared : right.shared;
+    out.exclusive = left.exclusive || right.exclusive;
+    out.borrow_conflict = left.borrow_conflict || right.borrow_conflict ||
+        (out.shared != 0 && out.exclusive != 0);
+    out.move_loc = left.move != FE_OWN_AVAILABLE ? left.move_loc : right.move_loc;
+    if (left.shared || left.exclusive || left.borrow_conflict)
+        out.borrow_loc = left.borrow_loc;
+    else
+        out.borrow_loc = right.borrow_loc;
+    return out;
+}
+
+int fe_own_state_equal(const FeOwnState *left, const FeOwnState *right)
+{
+    if (!left || !right) return 0;
+    return left->move == right->move &&
+           left->initialized == right->initialized &&
+           left->shared == right->shared &&
+           left->exclusive == right->exclusive &&
+           left->borrow_conflict == right->borrow_conflict;
+}
+
+FeOwnProvenance fe_own_provenance_static(void)
+{
+    FeOwnProvenance p;
+    p.kind = FE_OWN_PROV_STATIC;
+    p.param_index = 0;
+    return p;
+}
+
+FeOwnProvenance fe_own_provenance_param(unsigned param_index)
+{
+    FeOwnProvenance p;
+    p.kind = FE_OWN_PROV_PARAM;
+    p.param_index = param_index;
+    return p;
+}
+
+FeOwnProvenance fe_own_merge_provenance(FeOwnProvenance left,
+                                        FeOwnProvenance right)
+{
+    FeOwnProvenance invalid;
+    invalid.kind = FE_OWN_PROV_INVALID;
+    invalid.param_index = 0;
+    if (left.kind == FE_OWN_PROV_INVALID || right.kind == FE_OWN_PROV_INVALID)
+        return invalid;
+    if (left.kind == FE_OWN_PROV_STATIC) return right;
+    if (right.kind == FE_OWN_PROV_STATIC) return left;
+    if (left.param_index == right.param_index) return left;
+    return invalid;
+}
+
+void fe_own_liveness_init(FeOwnLiveness *live, FeArena *arena)
+{
+    if (!live) return;
+    live->arena = arena;
+    live->items = 0;
+    live->count = 0;
+    live->capacity = 0;
+    live->ordinal = 0;
+}
+
+static FeOwnLastUse *fe_own_live_find(FeOwnLiveness *live, const char *cname)
+{
+    unsigned i;
+    if (!live || !cname) return 0;
+    for (i = 0; i < live->count; ++i)
+        if (live->items[i].cname == cname ||
+            strcmp(live->items[i].cname, cname) == 0)
+            return &live->items[i];
+    return 0;
+}
+
+static int fe_own_live_add(FeOwnLiveness *live, FeNode *decl)
+{
+    FeOwnLastUse *items;
+    FeOwnLastUse *slot;
+    unsigned capacity;
+    const char *cname;
+    if (!live || !decl || !live->arena || !fe_own_is_reference_like(decl->sem_type))
+        return 1;
+    cname = decl->cname ? decl->cname : decl->text;
+    if (!cname || fe_own_live_find(live, cname)) return 1;
+    if (live->count == live->capacity) {
+        capacity = live->capacity ? live->capacity * 2U : 8U;
+        items = (FeOwnLastUse *)fe_arena_alloc(live->arena,
+            capacity * sizeof(FeOwnLastUse));
+        if (!items) return 0;
+        if (live->items)
+            memcpy(items, live->items, live->count * sizeof(FeOwnLastUse));
+        live->items = items;
+        live->capacity = capacity;
+    }
+    slot = &live->items[live->count++];
+    slot->cname = cname;
+    slot->decl = decl;
+    slot->last_node = 0;
+    slot->last_ordinal = 0;
+    slot->defer_extended = 0;
+    return 1;
+}
+
+static unsigned long fe_own_node_weight(FeNode *node);
+
+static unsigned long fe_own_list_weight(FeNode *node)
+{
+    unsigned long count;
+    count = 0;
+    while (node) {
+        count += fe_own_node_weight(node);
+        node = node->next;
+    }
+    return count;
+}
+
+static unsigned long fe_own_node_weight(FeNode *node)
+{
+    unsigned long count;
+    if (!node) return 0;
+    count = 1;
+    count += fe_own_node_weight(node->a);
+    count += fe_own_node_weight(node->b);
+    count += fe_own_node_weight(node->c);
+    count += fe_own_list_weight(node->children);
+    return count;
+}
+
+static int fe_own_live_visit(FeOwnLiveness *live, FeNode *node,
+                             unsigned long block_end,
+                             unsigned long defer_until);
+
+static int fe_own_live_visit_list(FeOwnLiveness *live, FeNode *node,
+                                  unsigned long block_end,
+                                  unsigned long defer_until)
+{
+    while (node) {
+        if (!fe_own_live_visit(live, node, block_end, defer_until)) return 0;
+        node = node->next;
+    }
+    return 1;
+}
+
+static int fe_own_live_visit(FeOwnLiveness *live, FeNode *node,
+                             unsigned long block_end,
+                             unsigned long defer_until)
+{
+    FeOwnLastUse *slot;
+    unsigned long end;
+    unsigned long effective;
+    if (!node) return 1;
+    ++live->ordinal;
+
+    if (node->kind == FE_N_IDENT) {
+        slot = fe_own_live_find(live, node->cname ? node->cname : node->text);
+        if (slot) {
+            effective = defer_until ? defer_until : live->ordinal;
+            if (effective >= slot->last_ordinal) {
+                slot->last_ordinal = effective;
+                slot->last_node = node;
+                if (defer_until) slot->defer_extended = 1;
+            }
+        }
+        return 1;
+    }
+
+    if (node->kind == FE_N_BLOCK) {
+        end = live->ordinal + fe_own_list_weight(node->children);
+        return fe_own_live_visit_list(live, node->children, end, defer_until);
+    }
+
+    if (node->kind == FE_N_DEFER) {
+        effective = defer_until ? defer_until : block_end;
+        return fe_own_live_visit(live, node->a, block_end, effective);
+    }
+
+    if (!fe_own_live_visit(live, node->a, block_end, defer_until)) return 0;
+    if (!fe_own_live_visit(live, node->b, block_end, defer_until)) return 0;
+    if (!fe_own_live_visit(live, node->c, block_end, defer_until)) return 0;
+    if (!fe_own_live_visit_list(live, node->children, block_end, defer_until))
+        return 0;
+
+    if (node->kind == FE_N_LET || node->kind == FE_N_VAR ||
+        node->kind == FE_N_CONST)
+        return fe_own_live_add(live, node);
+    return 1;
+}
+
+int fe_own_collect_last_uses(FeOwnLiveness *live, FeNode *fn)
+{
+    FeNode *param;
+    if (!live || !fn || fn->kind != FE_N_FN) return 0;
+    live->items = 0;
+    live->count = 0;
+    live->capacity = 0;
+    live->ordinal = 0;
+    for (param = fn->a ? fn->a->children : 0; param; param = param->next)
+        if (!fe_own_live_add(live, param)) return 0;
+    return fe_own_live_visit(live, fn->c, 0, 0);
+}
+
+const FeOwnLastUse *fe_own_last_use(const FeOwnLiveness *live,
+                                    const char *cname)
+{
+    unsigned i;
+    if (!live || !cname) return 0;
+    for (i = 0; i < live->count; ++i)
+        if (live->items[i].cname == cname ||
+            strcmp(live->items[i].cname, cname) == 0)
+            return &live->items[i];
+    return 0;
+}
+
 void fe_own_mark_consumed(FeDiags *diags, int *state, FeNode *decl,
                           FeNode *expr, FeType *type, int in_defer)
 {