Scalable incremental analysis using caller and callee summaries

A system, comprising:

• a memory coupled to a computer processor;
• a repository configured to store code comprising a plurality of components each comprising a plurality of summaries comprising (i) a forward summary comprising a forward flow and (ii) a backward summary comprising a backward flow, wherein the backward flow of the backward summary comprises a backward local parameter and a backward external parameter, and wherein the backward local parameter flows, during execution of the code, to the backward external parameter;
• and
• a code analyzer, executing on the computer processor and using the memory, configured to:
• generate the plurality of summaries for each of the plurality of components by performing a full analysis of the code,
• obtain a first modification to a modified component of the plurality of components,
• determine that one of the plurality of summaries for the modified component is invalid, and
• in response to determining that one of the plurality of summaries for the modified component is invalid:
• obtain the forward flow from the forward summary of the modified component,
• obtain the backward flow from the backward summary of the modified component,
• generate a local flow by performing an incremental analysis of the modified component using the forward flow of the modified component and the backward flow of the modified component, and
• detect a defect in the code using the forward flow of the modified component, the local flow, and the backward flow of the modified component.

A non-transitory computer readable medium comprising instructions that, when executed by a computer processor, perform:

• generating, by performing a full analysis of code and for each of a plurality of components of the code, a plurality of summaries comprising (i) a forward summary comprising a forward flow and (ii) a backward summary comprising a backward flow, wherein the backward flow of the backward summary comprises a backward local parameter and a backward external parameter, and wherein the backward local parameter flows, during execution of the code, to the backward external parameter;
• obtaining a first modification to a modified component of the plurality of components;
• determining that one of the plurality of summaries for the modified component is invalid;
• and
• in response to determining that one of the plurality of summaries for the modified component is invalid:
• obtaining the forward flow from the forward summary of the modified component;
• obtaining the backward flow from the backward summary of the modified component;
• generating a local flow by performing an incremental analysis of the modified component using the forward flow of the modified component and the backward flow of the modified component;
• and
• detecting a defect in the code using the forward flow of the modified component, the local flow, and the backward flow of the modified component.