Pub Date : 2022-05-27DOI: https://dl.acm.org/doi/full/10.1145/3502491
Jacob R. Lorch, Yixuan Chen, Manos Kapritsos, Haojun Ma, Bryan Parno, Shaz Qadeer, Upamanyu Sharma, James R. Wilcox, Xueyuan Zhao
Safely writing high-performance concurrent programs is notoriously difficult. To aid developers, we introduce Armada, a language and tool designed to formally verify such programs with relatively little effort. Via a C-like language and a small-step, state-machine-based semantics, Armadagives developers the flexibility to choose arbitrary memory layout and synchronization primitives so that they are never constrained in their pursuit of performance. To reduce developer effort, Armadaleverages SMT-powered automation and a library of powerful reasoning techniques, including rely-guarantee, TSO elimination, reduction, and pointer analysis. All of these techniques are proven sound, and Armadacan be soundly extended with additional strategies over time. Using Armada, we verify five concurrent case studies and show that we can achieve performance equivalent to that of unverified code.
{"title":"Armada: Automated Verification of Concurrent Code with Sound Semantic Extensibility","authors":"Jacob R. Lorch, Yixuan Chen, Manos Kapritsos, Haojun Ma, Bryan Parno, Shaz Qadeer, Upamanyu Sharma, James R. Wilcox, Xueyuan Zhao","doi":"https://dl.acm.org/doi/full/10.1145/3502491","DOIUrl":"https://doi.org/https://dl.acm.org/doi/full/10.1145/3502491","url":null,"abstract":"<p>Safely writing high-performance concurrent programs is notoriously difficult. To aid developers, we introduce Armada, a language and tool designed to formally verify such programs with relatively little effort. Via a C-like language and a small-step, state-machine-based semantics, Armadagives developers the flexibility to choose arbitrary memory layout and synchronization primitives so that they are never constrained in their pursuit of performance. To reduce developer effort, Armadaleverages SMT-powered automation and a library of powerful reasoning techniques, including rely-guarantee, TSO elimination, reduction, and pointer analysis. All of these techniques are proven sound, and Armadacan be soundly extended with additional strategies over time. Using Armada, we verify five concurrent case studies and show that we can achieve performance equivalent to that of unverified code.</p>","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"95 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138531545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Richter, David Kretzler, P. Weisenburger, G. Salvaneschi, Sebastian Faust, M. Mezini
Decentralized applications (dApps) consist of smart contracts that run on blockchains and clients that model collaborating parties. dApps are used to model financial and legal business functionality. Today, contracts and clients are written as separate programs—in different programming languages—communicating via send and receive operations. This makes distributed program flow awkward to express and reason about, increasing the potential for mismatches in the client-contract interface, which can be exploited by malicious clients, potentially leading to huge financial losses. In this article, we present Prisma , a language for tierless decentralized applications, where the contract and its clients are defined in one unit and pairs of send and receive actions that “belong together” are encapsulated into a single direct-style operation, which is executed differently by sending and receiving parties. This enables expressing distributed program flow via standard control flow and renders mismatching communication impossible. We prove formally that our compiler preserves program behavior in presence of an attacker controlling the client code. We systematically compare Prisma with mainstream and advanced programming models for dApps and provide empirical evidence for its expressiveness and performance.
{"title":"Prisma : A Tierless Language for Enforcing Contract-client Protocols in Decentralized Applications","authors":"D. Richter, David Kretzler, P. Weisenburger, G. Salvaneschi, Sebastian Faust, M. Mezini","doi":"10.1145/3604629","DOIUrl":"https://doi.org/10.1145/3604629","url":null,"abstract":"Decentralized applications (dApps) consist of smart contracts that run on blockchains and clients that model collaborating parties. dApps are used to model financial and legal business functionality. Today, contracts and clients are written as separate programs—in different programming languages—communicating via send and receive operations. This makes distributed program flow awkward to express and reason about, increasing the potential for mismatches in the client-contract interface, which can be exploited by malicious clients, potentially leading to huge financial losses. In this article, we present Prisma , a language for tierless decentralized applications, where the contract and its clients are defined in one unit and pairs of send and receive actions that “belong together” are encapsulated into a single direct-style operation, which is executed differently by sending and receiving parties. This enables expressing distributed program flow via standard control flow and renders mismatching communication impossible. We prove formally that our compiler preserves program behavior in presence of an attacker controlling the client code. We systematically compare Prisma with mainstream and advanced programming models for dApps and provide empirical evidence for its expressiveness and performance.","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"45 1","pages":"1 - 41"},"PeriodicalIF":1.3,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48929528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alex Sanchez-Stern, E. First, Timothy Zhou, Zhanna Kaufman, Yuriy Brun, T. Ringer
Formally verifying system properties is one of the most effective ways of improving system quality, but its high manual effort requirements often render it prohibitively expensive. Tools that automate formal verification by learning from proof corpora to synthesize proofs have just begun to show their promise. These tools are effective because of the richness of the data the proof corpora contain. This richness comes from the stylistic conventions followed by communities of proof developers, together with the powerful logical systems beneath proof assistants. However, this richness remains underexploited, with most work thus far focusing on architecture rather than on how to make the most of the proof data. This article systematically explores how to most effectively exploit one aspect of that proof data: identifiers. We develop the Passport approach, a method for enriching the predictive Coq model used by an existing proof-synthesis tool with three new encoding mechanisms for identifiers: category vocabulary indexing, subword sequence modeling, and path elaboration. We evaluate our approach’s enrichment effect on three existing base tools: ASTactic, Tac, and Tok. In head-to-head comparisons, Passport automatically proves 29% more theorems than the best-performing of these base tools. Combining the three tools enhanced by the Passport approach automatically proves 38% more theorems than combining the three base tools. Finally, together, these base tools and their enhanced versions prove 45% more theorems than the combined base tools. Overall, our findings suggest that modeling identifiers can play a significant role in improving proof synthesis, leading to higher-quality software.
{"title":"Passport: Improving Automated Formal Verification Using Identifiers","authors":"Alex Sanchez-Stern, E. First, Timothy Zhou, Zhanna Kaufman, Yuriy Brun, T. Ringer","doi":"10.1145/3593374","DOIUrl":"https://doi.org/10.1145/3593374","url":null,"abstract":"Formally verifying system properties is one of the most effective ways of improving system quality, but its high manual effort requirements often render it prohibitively expensive. Tools that automate formal verification by learning from proof corpora to synthesize proofs have just begun to show their promise. These tools are effective because of the richness of the data the proof corpora contain. This richness comes from the stylistic conventions followed by communities of proof developers, together with the powerful logical systems beneath proof assistants. However, this richness remains underexploited, with most work thus far focusing on architecture rather than on how to make the most of the proof data. This article systematically explores how to most effectively exploit one aspect of that proof data: identifiers. We develop the Passport approach, a method for enriching the predictive Coq model used by an existing proof-synthesis tool with three new encoding mechanisms for identifiers: category vocabulary indexing, subword sequence modeling, and path elaboration. We evaluate our approach’s enrichment effect on three existing base tools: ASTactic, Tac, and Tok. In head-to-head comparisons, Passport automatically proves 29% more theorems than the best-performing of these base tools. Combining the three tools enhanced by the Passport approach automatically proves 38% more theorems than combining the three base tools. Finally, together, these base tools and their enhanced versions prove 45% more theorems than the combined base tools. Overall, our findings suggest that modeling identifiers can play a significant role in improving proof synthesis, leading to higher-quality software.","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"45 1","pages":"1 - 30"},"PeriodicalIF":1.3,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48192343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingmei Hu, Eric Lu, David A. Holland, Ming Kawaguchi, Stephen Chong, M. Seltzer
The end of Moore’s Law has ushered in a diversity of hardware not seen in decades. Operating system (OS) (and system software) portability is accordingly becoming increasingly critical. Simultaneously, there has been tremendous progress in program synthesis. We set out to explore the feasibility of using modern program synthesis to generate the machine-dependent parts of an operating system. Our ultimate goal is to generate new ports automatically from descriptions of new machines. One of the issues involved is writing specifications, both for machine-dependent operating system functionality and for instruction set architectures. We designed two domain-specific languages: Alewife for machine-independent specifications of machine-dependent operating system functionality and Cassiopea for describing instruction set architecture semantics. Automated porting also requires an implementation. We developed a toolchain that, given an Alewife specification and a Cassiopea machine description, specializes the machine-independent specification to the target instruction set architecture and synthesizes an implementation in assembly language with a customized symbolic execution engine. Using this approach, we demonstrate the successful synthesis of a total of 140 OS components from two pre-existing OSes for four real hardware platforms. We also developed several optimization methods for OS-related assembly synthesis to improve scalability. The effectiveness of our languages and ability to synthesize code for all 140 specifications is evidence of the feasibility of program synthesis for machine-dependent OS code. However, many research challenges remain; we also discuss the benefits and limitations of our synthesis-based approach to automated OS porting.
{"title":"Towards Porting Operating Systems with Program Synthesis","authors":"Jingmei Hu, Eric Lu, David A. Holland, Ming Kawaguchi, Stephen Chong, M. Seltzer","doi":"10.1145/3563943","DOIUrl":"https://doi.org/10.1145/3563943","url":null,"abstract":"The end of Moore’s Law has ushered in a diversity of hardware not seen in decades. Operating system (OS) (and system software) portability is accordingly becoming increasingly critical. Simultaneously, there has been tremendous progress in program synthesis. We set out to explore the feasibility of using modern program synthesis to generate the machine-dependent parts of an operating system. Our ultimate goal is to generate new ports automatically from descriptions of new machines. One of the issues involved is writing specifications, both for machine-dependent operating system functionality and for instruction set architectures. We designed two domain-specific languages: Alewife for machine-independent specifications of machine-dependent operating system functionality and Cassiopea for describing instruction set architecture semantics. Automated porting also requires an implementation. We developed a toolchain that, given an Alewife specification and a Cassiopea machine description, specializes the machine-independent specification to the target instruction set architecture and synthesizes an implementation in assembly language with a customized symbolic execution engine. Using this approach, we demonstrate the successful synthesis of a total of 140 OS components from two pre-existing OSes for four real hardware platforms. We also developed several optimization methods for OS-related assembly synthesis to improve scalability. The effectiveness of our languages and ability to synthesize code for all 140 specifications is evidence of the feasibility of program synthesis for machine-dependent OS code. However, many research challenges remain; we also discuss the benefits and limitations of our synthesis-based approach to automated OS porting.","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"45 1","pages":"1 - 70"},"PeriodicalIF":1.3,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44682882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1007/978-3-031-21037-2
{"title":"Programming Languages and Systems: 20th Asian Symposium, APLAS 2022, Auckland, New Zealand, December 5, 2022, Proceedings","authors":"","doi":"10.1007/978-3-031-21037-2","DOIUrl":"https://doi.org/10.1007/978-3-031-21037-2","url":null,"abstract":"","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"15 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73804402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1007/978-3-030-99336-8
{"title":"Programming Languages and Systems: 31st European Symposium on Programming, ESOP 2022, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022, Munich, Germany, April 2–7, 2022, Proceedings","authors":"","doi":"10.1007/978-3-030-99336-8","DOIUrl":"https://doi.org/10.1007/978-3-030-99336-8","url":null,"abstract":"","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"26 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74336642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matteo Busi, Job Noorman, Jo Van Bulck, Letterio Galletta, P. Degano, J. Mühlberg, F. Piessens
Computer systems often provide hardware support for isolation mechanisms such as privilege levels, virtual memory, or enclaved execution. Over the past years, several successful software-based side-channel attacks have been developed that break, or at least significantly weaken, the isolation that these mechanisms offer. Extending a processor with new architectural or micro-architectural features brings a risk of introducing new software-based side-channel attacks. This article studies the problem of extending a processor with new features without weakening the security of the isolation mechanisms that the processor offers. Our solution is heavily based on techniques from research on programming languages. More specifically, we propose to use the programming language concept of full abstraction as a general formal criterion for the security of a processor extension. We instantiate the proposed criterion to the concrete case of extending a microprocessor that supports enclaved execution with secure interruptibility. This is a very relevant instantiation, as several recent papers have shown that interruptibility of enclaves leads to a variety of software-based side-channel attacks. We propose a design for interruptible enclaves and prove that it satisfies our security criterion. We also implement the design on an open-source enclave-enabled microprocessor and evaluate the cost of our design in terms of performance and hardware size.
{"title":"Securing Interruptible Enclaved Execution on Small Microprocessors","authors":"Matteo Busi, Job Noorman, Jo Van Bulck, Letterio Galletta, P. Degano, J. Mühlberg, F. Piessens","doi":"10.1145/3470534","DOIUrl":"https://doi.org/10.1145/3470534","url":null,"abstract":"Computer systems often provide hardware support for isolation mechanisms such as privilege levels, virtual memory, or enclaved execution. Over the past years, several successful software-based side-channel attacks have been developed that break, or at least significantly weaken, the isolation that these mechanisms offer. Extending a processor with new architectural or micro-architectural features brings a risk of introducing new software-based side-channel attacks.\u0000 \u0000 This article studies the problem of extending a processor with new features\u0000 without\u0000 weakening the security of the isolation mechanisms that the processor offers. Our solution is heavily based on techniques from research on programming languages. More specifically, we propose to use the programming language concept of full abstraction as a general formal criterion for the security of a processor extension. We instantiate the proposed criterion to the concrete case of extending a microprocessor that supports enclaved execution with secure interruptibility. This is a very relevant instantiation, as several recent papers have shown that interruptibility of enclaves leads to a variety of software-based side-channel attacks. We propose a design for interruptible enclaves and prove that it satisfies our security criterion. We also implement the design on an open-source enclave-enabled microprocessor and evaluate the cost of our design in terms of performance and hardware size.\u0000","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"20 1","pages":"12:1-12:77"},"PeriodicalIF":1.3,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85904738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Modern “safe” programming languages follow a design principle that we call safety by default and performance by choice . By default, these languages enforce important programming abstractions, such as memory and type safety, but they also provide mechanisms that allow expert programmers to explicitly trade some safety guarantees for increased performance. However, these same languages have adopted the inverse design principle in their support for multithreading. By default, multithreaded programs violate important abstractions, such as program order and atomic access to individual memory locations to admit compiler and hardware optimizations that would otherwise need to be restricted. Not only does this approach conflict with the design philosophy of safe languages, but very little is known about the practical performance cost of providing a stronger default semantics. In this article, we propose a safe-by-default and performance-by-choice multithreading semantics for safe languages, which we call volatile -by-default . Under this semantics, programs have sequential consistency (SC) by default, which is the natural “interleaving” semantics of threads. However, the volatile -by-default design also includes annotations that allow expert programmers to avoid the associated overheads in performance-critical code. We describe the design, implementation, optimization, and evaluation of the volatile -by-default semantics for two different safe languages: Java and Julia. First, we present V BD-HotSpot and V BDA-HotSpot, modifications of Oracle’s HotSpot JVM that enforce the volatile -by-default semantics on Intel x86-64 hardware and ARM-v8 hardware. Second, we present S C-Julia, a modification to the just-in-time compiler within the standard Julia implementation that provides best-effort enforcement of the volatile -by-default semantics on x86-64 hardware for the purpose of performance evaluation. We also detail two different implementation techniques: a baseline approach that simply reuses existing mechanisms in the compilers for handling atomic accesses, and a speculative approach that avoids the overhead of enforcing the volatile -by-default semantics until there is the possibility of an SC violation. Our results show that the cost of enforcing SC is significant but arguably still acceptable for some use cases today. Further, we demonstrate that compiler optimizations as well as programmer annotations can reduce the overhead considerably.
{"title":"Safe-by-default Concurrency for Modern Programming Languages","authors":"Lun Liu, T. Millstein, M. Musuvathi","doi":"10.1145/3462206","DOIUrl":"https://doi.org/10.1145/3462206","url":null,"abstract":"Modern “safe” programming languages follow a design principle that we call\u0000 safety by default\u0000 and\u0000 performance by choice\u0000 . By default, these languages enforce important programming abstractions, such as memory and type safety, but they also provide mechanisms that allow expert programmers to explicitly trade some safety guarantees for increased performance. However, these same languages have adopted the inverse design principle in their support for multithreading. By default, multithreaded programs violate important abstractions, such as program order and atomic access to individual memory locations to admit compiler and hardware optimizations that would otherwise need to be restricted. Not only does this approach conflict with the design philosophy of safe languages, but very little is known about the practical performance cost of providing a stronger default semantics.\u0000 \u0000 \u0000 In this article, we propose a safe-by-default and performance-by-choice multithreading semantics for safe languages, which we call\u0000 \u0000 volatile\u0000 \u0000 -by-default\u0000 . Under this semantics, programs have\u0000 sequential consistency\u0000 (SC) by default, which is the natural “interleaving” semantics of threads. However, the\u0000 volatile\u0000 -by-default design also includes annotations that allow expert programmers to avoid the associated overheads in performance-critical code. We describe the design, implementation, optimization, and evaluation of the\u0000 volatile\u0000 -by-default semantics for two different safe languages: Java and Julia. First, we present\u0000 V\u0000 BD-HotSpot and\u0000 V\u0000 BDA-HotSpot, modifications of Oracle’s HotSpot JVM that enforce the\u0000 volatile\u0000 -by-default semantics on Intel x86-64 hardware and ARM-v8 hardware. Second, we present\u0000 S\u0000 C-Julia, a modification to the just-in-time compiler within the standard Julia implementation that provides best-effort enforcement of the\u0000 volatile\u0000 -by-default semantics on x86-64 hardware for the purpose of performance evaluation. We also detail two different implementation techniques: a\u0000 baseline\u0000 approach that simply reuses existing mechanisms in the compilers for handling atomic accesses, and a\u0000 speculative\u0000 approach that avoids the overhead of enforcing the\u0000 volatile\u0000 -by-default semantics until there is the possibility of an SC violation. Our results show that the cost of enforcing SC is significant but arguably still acceptable for some use cases today. Further, we demonstrate that compiler optimizations as well as programmer annotations can reduce the overhead considerably.","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"3 1","pages":"10:1-10:50"},"PeriodicalIF":1.3,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87583363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work exploits the logical foundation of session types to determine what kind of type discipline for the Λ-calculus can exactly capture, and is captured by, Λ-calculus behaviours. Leveraging th...
{"title":"On Polymorphic Sessions and Functions: A Tale of Two (Fully Abstract) Encodings","authors":"ToninhoBernardo, YoshidaNobuko","doi":"10.1145/3457884","DOIUrl":"https://doi.org/10.1145/3457884","url":null,"abstract":"This work exploits the logical foundation of session types to determine what kind of type discipline for the Λ-calculus can exactly capture, and is captured by, Λ-calculus behaviours. Leveraging th...","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"6 1","pages":"1-55"},"PeriodicalIF":1.3,"publicationDate":"2021-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74345067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a framework to verify both, functional correctness and (amortized) worst-case complexity of practically efficient algorithms. We implemented a stepwise refinement approach, using the novel concept of resource currencies to naturally structure the resource analysis along the refinement chain, and allow a fine-grained analysis of operation counts. Our framework targets the LLVM intermediate representation. We extend its semantics from earlier work with a cost model. As case studies, we verify the amortized constant time push operation on dynamic arrays and the O(nlog n) introsort algorithm, and refine them down to efficient LLVM implementations. Our sorting algorithm performs on par with the state-of-the-art implementation found in the GNU C++ Library, and provably satisfies the complexity required by the C++ standard.
{"title":"For a Few Dollars More","authors":"Maximilian P. L. Haslbeck, P. Lammich","doi":"10.1145/3486169","DOIUrl":"https://doi.org/10.1145/3486169","url":null,"abstract":"We present a framework to verify both, functional correctness and (amortized) worst-case complexity of practically efficient algorithms. We implemented a stepwise refinement approach, using the novel concept of resource currencies to naturally structure the resource analysis along the refinement chain, and allow a fine-grained analysis of operation counts. Our framework targets the LLVM intermediate representation. We extend its semantics from earlier work with a cost model. As case studies, we verify the amortized constant time push operation on dynamic arrays and the O(nlog n) introsort algorithm, and refine them down to efficient LLVM implementations. Our sorting algorithm performs on par with the state-of-the-art implementation found in the GNU C++ Library, and provably satisfies the complexity required by the C++ standard.","PeriodicalId":50939,"journal":{"name":"ACM Transactions on Programming Languages and Systems","volume":"1 1","pages":"292 - 319"},"PeriodicalIF":1.3,"publicationDate":"2021-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74729504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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