preprocess

Documentation

Overview

Package preprocess hosts preprocessing logic for the input (e.g., CFGs etc.) to make it more amenable to analysis.

Index

• type Preprocessor
  • func New(pass *analysis.Pass) *Preprocessor
  • func (p *Preprocessor) CFG(graph *cfg.CFG, funcDecl *ast.FuncDecl) *cfg.CFG

Types

type Preprocessor

type Preprocessor struct {
	// contains filtered or unexported fields
}

Preprocessor handles different preprocessing logic for different types of input.

func New

func New(pass *analysis.Pass) *Preprocessor

New returns a new Preprocessor.

func (*Preprocessor) CFG

func (p *Preprocessor) CFG(graph *cfg.CFG, funcDecl *ast.FuncDecl) *cfg.CFG

CFG performs several passes on the CFG of utility to our analysis and returns a shallow copy of the modified CFG, with the original CFG untouched.

Specifically, it performs the following modifications to the CFG:

Canonicalize conditionals: - replace `if !cond {T} {F}` with `if cond {F} {T}` (swap successors) - replace `if cond1 && cond2 {T} {F}` with `if cond1 {if cond2 {T} else {F}}{F}` (nesting) - replace `if cond1 || cond2 {T} {F}` with `if cond1 {T} else {if cond2 {T} else {F}}` (nesting)

Canonicalize nil comparisons: It also performs the following useful transformation: - replace `if x != nil {T} {F}` with `if x == nil {F} {T}` (swap successors) - replace `nil == x {T} {F}` with `if x == nil {T} {F}` (swap comparison order)

Canonicalize explicit boolean comparisons: - replace `if x == true {T} {F}` with `if x {T} {F}` - replace `if x == false {T} {F}` with `if !x {T} {F}`