Fast, combined forwards-backwards pass global optimization framework for dynamic compilers

A computing device, comprising:

• a memory;
• and
• a processor coupled to the memory, wherein the processor is configured with processor-executable instructions to perform operations comprising:
• generating a graph from an intermediate representation of source code, wherein the graph comprises a plurality of nodes;
• initializing a ready list;
• adding a start node to the ready list;
• selecting a node in the ready list;
• incrementing a visitation counter of the selected node;
• determining whether the selected node has been visited more than twice;
• determining whether to apply a forwards optimization on the selected node in response to determining that the selected node has not been visited more than twice;
• applying the forwards optimization on the selected node in response to determining to apply the forwards optimization on the selected node;
• recognizing a bounded subgraph based on the selected node;
• initializing a successor list;
• adding all successors of the selected node in the bounded subgraph to the successor list;
• choosing a successor node from the successor list;
• incrementing a visitation counter of the chosen successor node;
• determining whether the chosen successor node has been visited more than twice;
• determining whether to apply the forwards optimization on the chosen successor node in response to determining that the chosen successor node has not been visited twice;
• applying the forwards optimization on the chosen successor node in response to determining to apply the forwards optimization;
• determining whether the chosen successor node is an exit node;
• adding successors of the chosen successor node to the successor list unless it is determined that the chosen successor node is an exit node or it is determined not to apply the forwards optimization on the chosen successor node;
• and
• removing the chosen successor node from the successor list.

A computing device, comprising:

• means for generating a graph from an intermediate representation of source code, wherein the graph comprises a plurality of nodes;
• means for initializing a ready list;
• means for adding a start node to the ready list;
• means for selecting a node in the ready list;
• means for incrementing a visitation counter of the selected node;
• means for determining whether the selected node has been visited more than twice;
• means for determining whether to apply a forwards optimization on the selected node in response to determining that the selected node has not been visited more than twice;
• means for applying the forwards optimization on the selected node in response to determining to apply the forwards optimization on the selected node;
• means for recognizing a bounded subgraph based on the selected node;
• means for initializing a successor list;
• means for adding all successors of the selected node in the bounded subgraph to the successor list;
• means for choosing a successor node from the successor list;
• means for incrementing a visitation counter of the chosen successor node;
• means for determining whether the chosen successor node has been visited more than twice;
• means for determining whether to apply the forwards optimization on the chosen successor node in response to determining that the chosen successor node has not been visited twice;
• means for applying the forwards optimization on the chosen successor node in response to determining to apply the forwards optimization;
• means for determining whether the chosen successor node is an exit node;
• means for adding successors of the chosen successor node to the successor list unless it is determined that the chosen successor node is an exit node or it is determined not to apply the forwards optimization on the chosen successor node;
• and
• means for removing the chosen successor node from the successor list.

A non-transitory processor-readable storage medium having stored thereon processor-executable software instructions configured to cause a processor of a computing device to perform operations for optimizing an intermediate representation of source code, the operations comprising:

• generating a graph from the intermediate representation, wherein the graph comprises a plurality of nodes;
• initializing a ready list;
• adding a start node to the ready list;
• selecting a node in the ready list;
• incrementing a visitation counter of the selected node;
• determining whether the selected node has been visited more than twice;
• determining whether to apply a forwards optimization on the selected node in response to determining that the selected node has not been visited more than twice;
• applying the forwards optimization on the selected node in response to determining to apply the forwards optimization on the selected node;
• recognizing a bounded subgraph based on the selected node;
• initializing a successor list;
• adding all successors of the selected node in the bounded subgraph to the successor list;
• choosing a successor node from the successor list;
• incrementing a visitation counter of the chosen successor node;
• determining whether the chosen successor node has been visited more than twice;
• determining whether to apply the forwards optimization on the chosen successor node in response to determining that the chosen successor node has not been visited twice;
• applying the forwards optimization on the chosen successor node in response to determining to apply the forwards optimization;
• determining whether the chosen successor node is an exit node;
• adding successors of the chosen successor node to the successor list unless it is determined that the chosen successor node is an exit node or it is determined not to apply the forwards optimization on the chosen successor node;
• and
• removing the chosen successor node from the successor list.