This thesis makes a contribution to the field of Runtime Verification, a lightweight formal method for the analysis of computational systems. The contribution is made in multiple parts. First, a new language is introduced for the specification of properties at the source code level of programs. These properties tend to be with respect to program performance. Second, automatic monitoring and instrumentation techniques are introduced for the specification language. Third, an approach for explaining violations of these properties by program runs is introduced. Finally, the resulting body of theoretical work is implemented in an extensive ecosystem of tools for program analysis. This ecosystem is described in detail, along with its application to a real world system at CERN. The work presented in this thesis diverges from past work in the Runtime Verification community. Instead of focusing on maximising expressiveness of the specification formalism and solving the resulting monitoring and instrumentation problems, it focuses on introducing a language in which properties that often need to be checked over real-world programs can easily be expressed. In the direction of instrumentation, the source-code level of abstraction of our specification language allows an approach to instrumentation that diverges from much previous work. Many previous approaches have treated instrumentation as a separate problem from specification, usually providing a language in which one can describe how instrumentation should be performed. With our specification language, instrumentation can be performed automatically with respect to a specification. Further, an area that has received little attention in the Runtime Verification community is the analysis of verdicts resulting from monitoring programs with respect to specifications. The contributions to this area described in this thesis take the form of tools in the ecosystem. These tools enable detailed exploration of monitoring information, and mark a step towards automated generation of explanations of verdicts. Following the description of the extensive set of tools, this thesis concludes with an in depth discussion of their application to perform significant analyses of software used at CERN. Ultimately, the work described, including the theoretical foundations and implementations, forms the beginnings of a program analysis project whose aim, through continued development at CERN, is to enable detailed analysis of the performance of programs by software engineers with minimal effort
