Recent work has demonstrated the utility of machine learning (ML) in carrying out highly accurate predictions at runtime. One of the major challenges with using ML, however, is that the predictions lack certain guarantees. For such approaches to become practicable in security settings involving debloating and dynamic control flow monitoring, one must distinguish between mispredictions vs. attacks.

Qwerty is a high-level quantum programming language built on bases and functions rather than circuits. This new paradigm introduces new challenges in compilation, namely synthesizing circuits from basis translations and automatically specializing adjoint or predicated forms of functions. This paper presents ASDF, an open-source compiler for Qwerty that answers these challenges in compiling basis-oriented languages. Enabled with a novel high-level quantum IR implemented in the MLIR framework, our compiler produces OpenQASM 3 or QIR for either simulation or execution on hardware. Our compiler is evaluated by comparing the fault-tolerant resource requirements of generated circuits with other compilers, finding that ASDF produces circuits with comparable cost to prior circuit-oriented compilers.

Modern C/C++ applications are susceptible to Non-Control Data Attacks, where an adversary attempts to exploit memory corruption vulnerabilities for security breaches such as privilege escalation, control-flow manipulation, etc. One such popular class of non-control data attacks is Control-flow Bending, where the attacker manipulates the program data to flip branch outcomes, and divert the program control flow into alternative paths to gain privileges. Unfortunately, despite tremendous advancements in software security, state-of-art defense mechanisms such as Control-flow Integrity (CFI), are ineffective against control-flow bending attacks especially those involving flipping of branch predicates.

Modern code reuse attacks take full advantage of bloated software. Attackers piece together short sequences of instructions in otherwise benign code to carry out malicious actions. Mitigating these reusable code snippets, known as gadgets, has become one of the prime focuses of attack surface reduction research. While some debloating techniques remove parts of software that contain such gadgets, other methods focus on making them unusable by breaking up chains of them, thereby substantially diminishing the possibility of code reuse attacks. Third-party libraries are another main focus, because they exhibit a high number of vulnerabilities, but recently, techniques have emerged that deal with whole applications. Attack surface reduction efforts have typically tried to eliminate such attacks by subsetting (debloating) the application, e.g. via user-specified inputs, configurations, or features to achieve high gadget reductions. However, such techniques suffer from the limitations of soundness, i.e. the software might crash during no-attack executions on regular inputs, or they may be conservative and leave a large amount of attack surface untackled.

Efficient management of shared resources is a critical problem in high-performance computing (HPC) environments. Existing workload management systems often promote non-sharing of resources among different co-executing applications to achieve performance isolation. Such schemes lead to poor resource utilization and suboptimal process throughput, adversely affecting user productivity. Tackling this problem in a scalable fashion is extremely challenging, since it requires the workload scheduler to possess an in-depth knowledge about various application resource requirements and runtime phases at fine granularities within individual applications. In this work, we show that applications’ resource requirements and execution phase behaviour can be captured in a scalable and lightweight manner at runtime by estimating important program artifacts termed as “ dynamic loop characteristics ”. Specifically, we propose a solution to the problem of efficient workload scheduling by designing a compiler and runtime cooperative framework that leverages novel loop-based compiler analysis for resource allocation . We present Beacons Framework , an end-to-end compiler and scheduling framework, that estimates dynamic loop characteristics, encapsulates them in compiler-instrumented beacons in an application, and broadcasts them during application runtime, for proactive workload scheduling. We focus on estimating four important loop characteristics : loop trip-count , loop timing , loop memory footprint , and loop data-reuse behaviour , through a combination of compiler analysis and machine learning. The novelty of the Beacons Framework also lies in its ability to tackle irregular loops that exhibit complex control flow with indeterminate loop bounds involving structure fields, aliased variables and function calls , which are highly prevalent in modern workloads. At the backend, Beacons Framework entails a proactive workload scheduler that leverages the runtime information to orchestrate aggressive process co-locations, for maximizing resource concurrency, without causing cache thrashing . Our results show that Beacons Framework can predict different loop characteristics with an accuracy of 85% to 95% on average, and the proactive scheduler obtains an average throughput improvement of 1.9x (up to 3.2x ) over the state-of-the-art schedulers on an Amazon Graviton2 machine on consolidated workloads involving 1000-10000 co-executing processes, across 51 benchmarks.

With a growing number of cores in modern high-performance servers, effective sharing of the last level cache (LLC) is more critical than ever. The primary agenda of such systems is to maximize performance by efficiently supporting multi-tenancy of diverse workloads. However, this could be particularly challenging to achieve in practice, because modern workloads exhibit dynamic phase behaviour, which causes their cache requirements & sensitivities to vary at finer granularities during execution. Unfortunately, existing systems are oblivious to the application phase behavior, and are unable to detect and react quickly enough to these rapidly changing cache requirements, often incurring significant performance degradation.

In spite of tremendous advances in data dependence and dataflow analysis techniques, state-of-the-art optimizing compilers continue to suffer from imprecisions and miss potential optimization opportunities. These imprecisions result from statically unknown characteristics of variables that participate in the dependence systems, or aliases that affect key safety properties, which must be conservatively assumed. However, with the increased tractability of verification on modern systems, a demand-driven solution to this problem can be envisioned. In this work, we model loop optimization constraints as loop-invariants, with the goal of proving their runtime behaviour under all inputs. Our proposed framework VICO, first detects the unresolved constraints whose conservative assumption negatively affects specific compiler optimizations. These constraints are then modeled as potential invariants and are verified on a demand-driven basis. Finally, VICO incorporates the verified invariants in the analysis, which results in superior optimization. For this purpose, VICO converts conservative constraints identified by the LLVM compiler and parallelization tool PLuTo, to potential invariants, that are further verified by SMACK verification tool. Following such an approach enables us to target numerous optimizations at different compilation phases - automatic parallelization and loop transformations at the source-level, and register allocation, and global value numbering (GVN), at the IR-level. Our results show that VICO improves the precision of dependence analysis by 45% in real-world cases, leading to superior optimization in over 75 loops in different scenarios like mathematical simulations and solvers. The improvement in dependence precision led to an average speedup of 14.7x on Apple M1 Pro and 6.07x on Intel Xeon E5-2660 systems. In addition, VICO also enhances LLVM's alias analysis leading to improvements in LLVM backend optimizations and decreased code size by 4% alongside improved execution time by 2.2% in numerous linux programs and SPEC benchmarks with (mostly) low verification time.