112 lines
2.6 KiB
Go
112 lines
2.6 KiB
Go
|
package qf1005
|
||
|
|
|
||
|
|
import (
|
||
|
|
"go/ast"
|
||
|
|
"go/constant"
|
||
|
|
"go/token"
|
||
|
|
"go/types"
|
||
|
|
|
||
|
|
"honnef.co/go/tools/analysis/code"
|
||
|
|
"honnef.co/go/tools/analysis/edit"
|
||
|
|
"honnef.co/go/tools/analysis/lint"
|
||
|
|
"honnef.co/go/tools/analysis/report"
|
||
|
|
"honnef.co/go/tools/go/ast/astutil"
|
||
|
|
"honnef.co/go/tools/pattern"
|
||
|
|
|
||
|
|
"golang.org/x/tools/go/analysis"
|
||
|
|
)
|
||
|
|
|
||
|
|
var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
|
||
|
|
Analyzer: &analysis.Analyzer{
|
||
|
|
Name: "QF1005",
|
||
|
|
Run: run,
|
||
|
|
Requires: code.RequiredAnalyzers,
|
||
|
|
},
|
||
|
|
Doc: &lint.RawDocumentation{
|
||
|
|
Title: `Expand call to \'math.Pow\'`,
|
||
|
|
Text: `Some uses of \'math.Pow\' can be simplified to basic multiplication.`,
|
||
|
|
Before: `math.Pow(x, 2)`,
|
||
|
|
After: `x * x`,
|
||
|
|
Since: "2021.1",
|
||
|
|
Severity: lint.SeverityHint,
|
||
|
|
},
|
||
|
|
})
|
||
|
|
|
||
|
|
var Analyzer = SCAnalyzer.Analyzer
|
||
|
|
|
||
|
|
var mathPowQ = pattern.MustParse(`(CallExpr (Symbol "math.Pow") [x (IntegerLiteral n)])`)
|
||
|
|
|
||
|
|
func run(pass *analysis.Pass) (any, error) {
|
||
|
|
for node, matcher := range code.Matches(pass, mathPowQ) {
|
||
|
|
x := matcher.State["x"].(ast.Expr)
|
||
|
|
if code.MayHaveSideEffects(pass, x, nil) {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
n, ok := constant.Int64Val(constant.ToInt(matcher.State["n"].(types.TypeAndValue).Value))
|
||
|
|
if !ok {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
|
||
|
|
needConversion := false
|
||
|
|
if T, ok := pass.TypesInfo.Types[x]; ok && T.Value != nil {
|
||
|
|
info := types.Info{
|
||
|
|
Types: map[ast.Expr]types.TypeAndValue{},
|
||
|
|
}
|
||
|
|
|
||
|
|
// determine if the constant expression would have type float64 if used on its own
|
||
|
|
if err := types.CheckExpr(pass.Fset, pass.Pkg, x.Pos(), x, &info); err != nil {
|
||
|
|
// This should not happen
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if T, ok := info.Types[x].Type.(*types.Basic); ok {
|
||
|
|
if T.Kind() != types.UntypedFloat && T.Kind() != types.Float64 {
|
||
|
|
needConversion = true
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
needConversion = true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
var replacement ast.Expr
|
||
|
|
switch n {
|
||
|
|
case 0:
|
||
|
|
replacement = &ast.BasicLit{
|
||
|
|
Kind: token.FLOAT,
|
||
|
|
Value: "1.0",
|
||
|
|
}
|
||
|
|
case 1:
|
||
|
|
replacement = x
|
||
|
|
case 2, 3:
|
||
|
|
r := &ast.BinaryExpr{
|
||
|
|
X: x,
|
||
|
|
Op: token.MUL,
|
||
|
|
Y: x,
|
||
|
|
}
|
||
|
|
for i := 3; i <= int(n); i++ {
|
||
|
|
r = &ast.BinaryExpr{
|
||
|
|
X: r,
|
||
|
|
Op: token.MUL,
|
||
|
|
Y: x,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
rc, ok := astutil.CopyExpr(r)
|
||
|
|
if !ok {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
replacement = astutil.SimplifyParentheses(rc)
|
||
|
|
default:
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if needConversion && n != 0 {
|
||
|
|
replacement = &ast.CallExpr{
|
||
|
|
Fun: &ast.Ident{Name: "float64"},
|
||
|
|
Args: []ast.Expr{replacement},
|
||
|
|
}
|
||
|
|
}
|
||
|
|
report.Report(pass, node, "could expand call to math.Pow",
|
||
|
|
report.Fixes(edit.Fix("Expand call to math.Pow", edit.ReplaceWithNode(pass.Fset, node, replacement))))
|
||
|
|
}
|
||
|
|
return nil, nil
|
||
|
|
}
|