This article describes how data flow analysis is implemented in the CodeQL libraries for C/C++ and includes examples to help you write your own data flow queries. The following sections describe how to use the libraries for local data flow, global data flow, and taint tracking.

Oct 3, 2024 · Data flow analysis is a technique used in compiler design to analyze how data flows through a program. It involves tracking the values of variables and expressions as they are computed and used throughout the program, with the goal of identifying opportunities for optimization and identifying potential errors.

Nov 1, 2023 · Today, we’ll look at the basics of data flow analysis, including how it works in general, while presenting several real-world examples where it can help you write better code. All data flow inspections rely on the control-flow graph.

Oct 16, 2018 · There are some dataflow C++ libraries I have found: cellspp - allows to use spreadsheet evaluation model. DSPatch and Route11 - C++ dataflow frameworks. Allows to write programs in dataflow manner. Looks interesting.

Data Flow Analysis Schema • Build a flow graph (nodes = basic blocks, edges = control flow) • Set up a set of equations between in[b] and out[b] for all basic blocks b

Data-flow analysis: reaching definitions; Control Flow Graphs; Basic block; ANSI C Yacc grammar; Semantic Analysis Phases of Compilation; Classical Dataflow Optimizations

CFGs and dataflow analysis work for x86 assembly, imperative C-like source, LLVM IR, ... e.g. LLVM IR doesn’t have “imperative” update of %uid temporaries. SSA structure of the LLVM IR makes some of these analyses simpler.

Program Analysis Data Flow Analysis (Part 3) 26 Outline First example: Available expressions Basic principles More examples Solving data ow problems Inter-procedural analysis Sensitivities. 27 Data Flow Analyses Seen previously ... Useful, e.g., for identifyingdead code Bug detection: Dead assignments are typically unexpected Optimization ...

Data Flow Analysis Tundra is a toy language and dataflow analysis framework (more detail later). l1: x = 10; l2: y = 10; if (x == 10) {y = 3;} else { }

Exercise 1: What would the lattice for simple Sign Analysis look like? Extension of simple Sign Analysis to track when x<0, x<=0, x=0, x>=0, x>0, x!=0, or unknown ( ̄\_( ツ)_/ ̄). Q: Why do we care about all these cases? Exercise 2: What would the lattice for precise Sign Analysis look like?