SOFTWARE PRODUCT LINES: CONCEPTS AND IMPLEMENTATION QUALITY ASSURANCE: SAMPLING

Transcription

1 SOFTWARE PRODUCT LINES: CONCEPTS AND IMPLEMENTATION QUALITY ASSURANCE: SAMPLING CHRISTIAN KAESTNER CARNEGIE MELLON UNIVERSITY INSTITUTE FOR SOFTWARE RESEARCH

2 READING ASSIGNMENT NOV 16 Textbook Chapter 9 Nhlabatsi, Armstrong, Robin Laney, and Bashar Nuseibeh. "Feature interaction: the security threat from within software systems." Progress in Informatics 5 (2008):

3 LEARNING GOALS Understand the challenge of feature interactions Understand the challenges from requirements level down to implementations Implementation vs specification and emergent behavior Apply mitigation strategies

4 Checking Products 2000 Features 100 Printers 30 New Printers per Year Printer Firmware

5 Checking Products Features? Products Linux Kernel

6 Checking Product Line Implementation with Features #ifdef, Frameworks, FOP, AOP, Linux Kernel

7 DEAD IFDEF CODE DETECTION: UNDERTAKER

8 PRESENCE CONDITIONS line 1 #ifdef A line 2 #ifndef B line 3 line 4 #elif defined(x) line 5 #else line 6 true A A B A A X A X

9 DEAD CODE line 1 #ifdef A line 2 #ifndef A line 3 line 4 #elif defined(x) line 5 #else line 6 true A A A A A X A X Cannot be selected Analysis: SAT(PC(Block i)) Include feature model in reasoning!

10 DEAD CODE line 1 #ifdef A line 2 #ifdef B line 3 line 4 #elif defined(x) line 5 #else line 6 true A A B A A X not A ^ not X (A v B) (A B) Analysis: SAT(FM PC(Block i)) Analyze feature model and implementation Cannot be selected

11 OTHER QUESTIONS Which files are never compiled? Which feature modules cannot be included? Which plugins/packages always have conflicts? Which features never influence the source code? Which code fragments seem optional but are not?

12 FAMILY-BASED ANALYSIS

13 TYPE CHECKING #include <stdio.h> char *msg = "Hello World"; int main() { printf(msg); } Reference Type errors: referenced variable does not exist,

14 VARIABILITY-AWARE TYPE CHECKING #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); }

15 VARIABILITY-AWARE TYPE CHECKING #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); } Reference? Conflict?

16 VARIABILITY-AWARE TYPE CHECKING Presence conditions: true WORLD BYE true #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); } Reference? Conflict?

17 VARIABILITY-AWARE TYPE CHECKING true WORLD BYE true -> true true #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); } Reference? (WORLD BYE Conflict? true -> (WORLD v BYE)

18 REACHABILITY: PC(SOURCE) -> PC(TARGET) CONFLICTS: (PC(DEF1) PC(DEF2)) true WORLD BYE true -> true true #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); } Reference? (WORLD BYE Conflict? true -> (WORLD v BYE)

19 INCLUDING THE FEATURE MODEL WORL D P BYE true WORLD BYE FM -> (true -> true) true #include <stdio.h> #ifdef WORLD char *msg = "Hello World"; #ifdef BYE char *msg = "Bye bye!"; int main() { printf(msg); } Reference? FM -> (WORLD BYE) Conflict? FM -> (true -> (WORLD v BYE))

20 AST with Variability Information WORLD BYE 20 WORLD BYE Extended Reference lookup mechanism

21 TYPE SYSTEM IN CIDE

22 TYPE SYSTEM IN CIDE public class Test { private static String msg_hi = "Hello world! ; private static String msg_bye = "Bye bye!"; public static void main(string[] args) { System.out.println(msg_hi); System.out.println(msg_bye); } } Similar implementations available for FOP, AOP

23

24 Glue-code module

25 VARIABILITY ENCODING

26 Complete Analysis Product Configuration Variability-Aware Analysis Conventional Analysis

27 def gettype(e: V[Expr]): V[Type] int a = 1; int b = 0; #ifdef A int c = a; #else char c = a; if (c) { c += a; #ifdef B c /= b; }... int a = 1; int b = 0; c: V A int c = a; if (c) char c = a; c += a; V B V A c /= b; ε int char AST with Variability Information

28 def succ(s: Stmt): List[V[Stmt]] int a = 1; int b = 0; #ifdef A int c = a; #else char c = a; if (c) { c += a; #ifdef B c /= b; }... int a = 1; int b = 0; A char c = a; A A A c // if (c) B B 4 int c = a; V A 6 B c += a; c /= b; CFG with Variability Information

29 def live(s: Stmt): List[V[Var]] int a = 1; int b = 0; #ifdef A int c = a; #else char c = a; if (c) { c += a; #ifdef B c /= b; }... int a = 1; int b = 0; A char c = a; A A A c // if (c) B B 4 int c = a; 9 11 B a V B c += a; c /= b; b ε CFG with Variability Information

30 def forw(s: Stmt, p: State): List[V[State]] int a = 1; int b = 0; #ifdef A int c = a; #else char c = a; if (c) { c += a; #ifdef B c /= b; }... B ( A A) A a=1 b=0 c=1 a=1 b=0 c=1 a=1 b=0 a=1 b=0 c=1 A a=1 b=0 c=1 B B a=1 b=0 c=1 Division by zero in Line 11 ARG with Variability Information

31 MODULAR ANALYSIS (FEATURE-BASED)

32 interface Base; export class Stack { void push(int v); } interface Undo; import class Stack { void push(int v); void top(); } export class Stack { void undo(); }

33

34 DISCUSSION

35 PRINCIPLES Preserve sharing Late splitting, early joining Consider variability during analysis

36 ANALYSES Product-based Family-based Feature-based Combinations thereof Thüm, T., Apel, S., Kästner, C., Schaefer, I., & Saake, G. (2014). A classification and survey of analysis strategies for software product lines. ACM Computing Surveys (CSUR), 47(1), 6.

37 LOAD-TIME VARIABILITY

38 LOAD-TIME OPTIONS Read from configuration file/command-line options/ Assumptions: Constant at program start, does not change after Used differently from other variables (assigned, used in if statements; not part of computations) (Tool: LoTrack based on taint analysis)

39 39 Data-flow interactions? class ProxyService { static boolean NATIVE_PROXY_SUPPORTED = Build.VERSION.SDK_INT >= 12; public void onsharedpreferencechanged() { boolean a = false; if (!NATIVE_PROXY_SUPPORTED) { if (Context.getSystemService("bluetooth")) { a = true; }} if (a) { SDK>=12 SDK> BLUET. BLUE

40 FURTHER READING Krzysztof Czarnecki, Krzysztof Pietroszek: Verifying feature-based model templates against well-formedness OCL constraints. GPCE 2006: origin of whole-product line analysis Christian Kästner, Sven Apel, Thomas Thüm, and Gunter Saake Type checking annotation-based product lines. ACM Trans. Softw. Eng. Methodol. 21, 3, Article 14 (July 2012), 39 pages. -- application to conditional compilation in Java code TypeChef papers application to ifdefs in C code, scaling to Linux Thüm, T., Apel, S., Kästner, C., Schaefer, I., & Saake, G. (2014). A classification and survey of analysis strategies for software product lines. ACM Computing Surveys (CSUR), 47(1), 6.