l0_backend_lifetime.py

l0_backend_lifetime.py

Module: l0_backend_lifetime

Source: compiler/stage1_py/l0_backend_lifetime.py Language: Python

Symbols

Namespace l0_backend_lifetime

Class l0_backend_lifetime::ValueLifetime

ARC materialization, value retention/cleanup, and drop operations.

Member Data l0_backend_lifetime.ValueLifetime.convert

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OwnershipConversion convert

Member Data l0_backend_lifetime.ValueLifetime.state

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BackendState state

Function l0_backend_lifetime.ValueLifetime._is_unwrap_cast_from_place

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bool l0_backend_lifetime.ValueLifetime._is_unwrap_cast_from_place(self, Expr expr)

Check if a cast expression still borrows from an existing owner.

Outer parentheses are ownership-transparent. Owner-producing ARC value-optional wraps are excluded.

Parameters:

  • expr: The expression to check.

Returns: True for non-owner-producing casts whose source is a place.

Function l0_backend_lifetime.ValueLifetime._needs_arc_temp

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bool l0_backend_lifetime.ValueLifetime._needs_arc_temp(self, Expr expr)

Check if a non-place rvalue with ARC data needs temp materialization.

String literals are static constants and don’t need cleanup.

Parameters:

  • expr: The expression to check.

Returns: True if temp materialization is needed.

Function l0_backend_lifetime.ValueLifetime._should_materialize_arc_temp

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bool l0_backend_lifetime.ValueLifetime._should_materialize_arc_temp(self, Expr expr, Type expr_type)

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.

Function l0_backend_lifetime.ValueLifetime._materialize_arc_temp

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str l0_backend_lifetime.ValueLifetime._materialize_arc_temp(self, str c_expr, Type expr_type)

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.

Function l0_backend_lifetime.ValueLifetime._emit_cleanup_at_scope_exit

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None l0_backend_lifetime.ValueLifetime._emit_cleanup_at_scope_exit(self, ScopeContext scope)

Emit cleanup at scope exit.

Only cleans variables declared in THIS scope that have owned fields.

Parameters:

  • scope: The scope being exited.

    Function l0_backend_lifetime.ValueLifetime._emit_value_cleanup

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None l0_backend_lifetime.ValueLifetime._emit_value_cleanup(self, str c_expr, Type ty)

Emit cleanup code for a by-value variable before reassignment.

Similar to _emit_field_cleanup, but expects c_expr to be a direct value reference (not a pointer), so uses ‘.’ instead of ‘->’.

Parameters:

  • c_expr: C expression for the value (e.g., “x__v”, “obj.field”)
  • ty: The type of the value being cleaned up

    Function l0_backend_lifetime.ValueLifetime._emit_struct_cleanup

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None l0_backend_lifetime.ValueLifetime._emit_struct_cleanup(self, str c_ptr_expr, StructType struct_type)

Emit cleanup code for all owned fields in a struct.

Recursively handles nested structs (by-value fields).

Parameters:

  • c_ptr_expr: C expression evaluating to a pointer to the struct.
  • struct_type: The struct type.

    Function l0_backend_lifetime.ValueLifetime._emit_enum_cleanup

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None l0_backend_lifetime.ValueLifetime._emit_enum_cleanup(self, str c_ptr_expr, EnumType enum_type)

Emit cleanup code for owned fields in an enum’s active variant.

Uses switch on tag to only clean up the fields that are actually present.

Parameters:

  • c_ptr_expr: C expression evaluating to a pointer to the enum.
  • enum_type: The enum type.

    Function l0_backend_lifetime.ValueLifetime._emit_retain_for_copied_value

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None l0_backend_lifetime.ValueLifetime._emit_retain_for_copied_value(self, str c_expr, Type ty)

Emit retain operations for a copied owned value.

Used when copying from place expressions so source and destination own independent references.

Parameters:

  • c_expr: C expression evaluating to the value.
  • ty: The type of the value.

    Function l0_backend_lifetime.ValueLifetime._emit_copy_expr_with_retains

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str l0_backend_lifetime.ValueLifetime._emit_copy_expr_with_retains(self, str c_expr, Type ty)

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.

Function l0_backend_lifetime.ValueLifetime._emit_drop

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None l0_backend_lifetime.ValueLifetime._emit_drop(self, DropStmt stmt, str module_name)

Emit drop statement with automatic cleanup of owned fields.

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.

Parameters:

  • stmt: The DropStmt AST node.
  • module_name: Name of current module.