ValueLifetime class
Defined in module l0_backend_lifetime (l0_backend_lifetime.py).
ARC materialization, value retention/cleanup, and drop operations.
Public static attributes
- static OwnershipConversion convert
- static BackendState state
Protected functions
- auto _is_borrowed_extraction(self, Expr expr) -> bool
- Check whether casts or optional extraction borrow from an existing owner.
- auto _needs_arc_temp(self, Expr expr) -> bool
- Check if a non-place rvalue with ARC data needs temp materialization.
- auto _should_materialize_arc_temp(self, Expr expr, Type expr_type) -> bool
- Check if an ARC expression should be hoisted to a cleanup temp.
- auto _materialize_arc_temp(self, str c_expr, Type expr_type) -> str
- Materialize an ARC rvalue into a scope-owned temporary for automatic cleanup.
- auto _emit_cleanup_at_scope_exit(self, ScopeContext scope) -> None
- Emit cleanup at scope exit.
- auto _emit_value_cleanup(self, str c_expr, Type ty) -> None
- Emit cleanup code for a by-value variable before reassignment.
- auto _emit_struct_cleanup(self, str c_ptr_expr, StructType struct_type) -> None
- Emit cleanup code for all owned fields in a struct.
- auto _emit_enum_cleanup(self, str c_ptr_expr, EnumType enum_type) -> None
- Emit cleanup code for owned fields in an enum's active variant.
- auto _emit_retain_for_copied_value(self, str c_expr, Type ty) -> None
- Emit retain operations for a copied owned value.
- auto _emit_copy_expr_with_retains(self, str c_expr, Type ty) -> str
- Materialize copied values in a temp and emit retain logic when needed.
- auto _emit_drop(self, DropStmt stmt, str module_name) -> None
- Emit drop statement with automatic cleanup of owned fields.
Function documentation
bool l0_backend_lifetime::
Check whether casts or optional extraction borrow from an existing owner.
| Parameters | |
|---|---|
| expr | The expression to check. |
| Returns | True for non-owner-producing cast or try chains rooted in a place. |
Parentheses and non-owner-producing cast chains are ownership-transparent. Owner-producing ARC value-optional wraps stop the borrowed chain.
bool l0_backend_lifetime::
Check if a non-place rvalue with ARC data needs temp materialization.
| Parameters | |
|---|---|
| expr | The expression to check. |
| Returns | True if temp materialization is needed. |
String literals are static constants and don't need cleanup.
bool l0_backend_lifetime::
Check if an ARC expression should be hoisted to a cleanup temp.
| Parameters | |
|---|---|
| expr | The expression to check. |
| expr_type | The type of the expression. |
| Returns | True if the expression should be materialized into a temporary. |
str l0_backend_lifetime::
Materialize an ARC rvalue into a scope-owned temporary for automatic cleanup.
| Parameters | |
|---|---|
| c_expr | The C expression string. |
| expr_type | The type of the expression. |
| Returns | The name of the generated temporary variable. |
None l0_backend_lifetime::
Emit cleanup at scope exit.
| Parameters | |
|---|---|
| scope | The scope being exited. |
Only cleans variables declared in THIS scope that have owned fields.
None l0_backend_lifetime::
Emit cleanup code for a by-value variable before reassignment.
| Parameters | |
|---|---|
| c_expr | C expression for the value (e.g., "x__v", "obj.field") |
| ty | The type of the value being cleaned up |
Similar to _emit_field_cleanup, but expects c_expr to be a direct value reference (not a pointer), so uses '.' instead of '->'.
None l0_backend_lifetime::
Emit cleanup code for all owned fields in a struct.
| Parameters | |
|---|---|
| c_ptr_expr | C expression evaluating to a pointer to the struct. |
| struct_type | The struct type. |
Recursively handles nested structs (by-value fields).
None l0_backend_lifetime::
Emit cleanup code for owned fields in an enum's active variant.
| Parameters | |
|---|---|
| c_ptr_expr | C expression evaluating to a pointer to the enum. |
| enum_type | The enum type. |
Uses switch on tag to only clean up the fields that are actually present.
None l0_backend_lifetime::
Emit retain operations for a copied owned value.
| Parameters | |
|---|---|
| c_expr | C expression evaluating to the value. |
| ty | The type of the value. |
| Exceptions | |
| InternalCompilerError | If variant decl is missing for enum types. |
Used when copying from place expressions so source and destination own independent references.
str l0_backend_lifetime::
Materialize copied values in a temp and emit retain logic when needed.
| Parameters | |
|---|---|
| c_expr | C expression evaluating to the value. |
| ty | The type of the value. |
| Returns | The name of the temporary containing the copied and retained value. |
None l0_backend_lifetime::
Emit drop statement with automatic cleanup of owned fields.
| Parameters | |
|---|---|
| stmt | The DropStmt AST node. |
| module_name | Name of current module. |
| Exceptions | |
| InternalCompilerError | If variable is undefined or not a pointer. |
For structs: releases all string fields. For enums: switches on tag, releases strings in active variant. Then calls the drop-finish helper to release the memory.