def set_simple_var(decl, src):
'''Given a variable declaration (ASTParam or ASTVariableDeclaration), stores
the value of src in it.'''
store_code = []
if isinstance(decl, ast_param.ASTParam):
# Method parameter.
index = CodeGenManager.cur_method.c_get_param_index(decl)
store_code = common.set_param(index, src, CodeGenManager.N_PARAMS)
elif decl.c_parent_method is not None:
# Local variable.
store_code = common.save_local_var(decl, src)
else:
# Last remaining case is a instance field access on the enclosing type.
if not isinstance(decl, ast_variable_declaration.ASTVariableDeclaration):
raise Exception('Simple variable is not an instance field')
scratch_reg = [reg for reg in ['eax', 'ebx'] if reg != src][0]
store_code = [
'; using {0} as scratch'.format(scratch_reg),
'push {0} ; saving scratch'.format(scratch_reg),
common.get_param(scratch_reg, 0, CodeGenManager.N_PARAMS),
common.save_instance_field(scratch_reg, decl, src),
'pop {0} ; restoring scratch'.format(scratch_reg)
]
return store_code
def get_simple_var(decl):
'''Given a declaration, return code to get the variable'''
if isinstance(decl, ast_param.ASTParam):
# Method param.
index = CodeGenManager.cur_method.c_get_param_index(decl)
return common.get_param('eax', index, CodeGenManager.N_PARAMS)
elif decl.c_parent_method is not None:
# Local variable.
return common.get_local_var('eax', decl)
# Only remaining case should be an (instance) field of the encl type.
if not isinstance(decl, ast_variable_declaration.ASTVariableDeclaration):
raise Exception('Invalid instance var value retrieval.')
# "this" is always the first param from an implicit "this".
return [
'; Field access of implicit "this"',
common.get_param('eax', 0, CodeGenManager.N_PARAMS),
common.get_instance_field('eax', 'eax', decl)
]