147 lines
2.8 KiB
Go
147 lines
2.8 KiB
Go
package analysisutil
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import (
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"golang.org/x/tools/go/ssa"
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)
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// IfInstr returns *ssa.If which is contained in the block b.
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// If the block b has not any if instruction, IfInstr returns nil.
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func IfInstr(b *ssa.BasicBlock) *ssa.If {
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if len(b.Instrs) == 0 {
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return nil
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}
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ifinstr, ok := b.Instrs[len(b.Instrs)-1].(*ssa.If)
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if !ok {
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return nil
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}
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return ifinstr
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}
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// Phi returns phi values which are contained in the block b.
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func Phi(b *ssa.BasicBlock) (phis []*ssa.Phi) {
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for _, instr := range b.Instrs {
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if phi, ok := instr.(*ssa.Phi); ok {
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phis = append(phis, phi)
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} else {
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// no more phi
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break
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}
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}
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return
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}
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// Returns returns a slice of *ssa.Return in the function.
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func Returns(v ssa.Value) []*ssa.Return {
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var fn *ssa.Function
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switch v := v.(type) {
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case *ssa.Function:
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fn = v
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case *ssa.MakeClosure:
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return Returns(v.Fn)
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default:
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return nil
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}
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var rets []*ssa.Return
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done := map[*ssa.BasicBlock]bool{}
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for _, b := range fn.Blocks {
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rets = append(rets, returnsInBlock(b, done)...)
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}
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return rets
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}
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func returnsInBlock(b *ssa.BasicBlock, done map[*ssa.BasicBlock]bool) (rets []*ssa.Return) {
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if done[b] {
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return
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}
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done[b] = true
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if len(b.Instrs) != 0 {
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switch instr := b.Instrs[len(b.Instrs)-1].(type) {
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case *ssa.Return:
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rets = append(rets, instr)
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}
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}
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for _, s := range b.Succs {
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rets = append(rets, returnsInBlock(s, done)...)
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}
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return
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}
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// BinOp returns binary operator values which are contained in the block b.
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func BinOp(b *ssa.BasicBlock) []*ssa.BinOp {
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var binops []*ssa.BinOp
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for _, instr := range b.Instrs {
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if binop, ok := instr.(*ssa.BinOp); ok {
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binops = append(binops, binop)
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}
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}
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return binops
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}
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// Used returns an instruction which uses the value in the instructions.
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func Used(v ssa.Value, instrs []ssa.Instruction) ssa.Instruction {
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if len(instrs) == 0 || v.Referrers() == nil {
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return nil
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}
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for _, instr := range instrs {
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if used := usedInInstr(v, instr); used != nil {
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return used
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}
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}
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return nil
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}
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func usedInInstr(v ssa.Value, instr ssa.Instruction) ssa.Instruction {
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switch instr := instr.(type) {
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case *ssa.MakeClosure:
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return usedInClosure(v, instr)
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default:
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operands := instr.Operands(nil)
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for _, x := range operands {
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if x != nil && *x == v {
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return instr
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}
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}
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}
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switch v := v.(type) {
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case *ssa.UnOp:
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return usedInInstr(v.X, instr)
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}
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return nil
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}
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func usedInClosure(v ssa.Value, instr *ssa.MakeClosure) ssa.Instruction {
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fn, _ := instr.Fn.(*ssa.Function)
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if fn == nil {
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return nil
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}
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var fv *ssa.FreeVar
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for i := range instr.Bindings {
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if instr.Bindings[i] == v {
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fv = fn.FreeVars[i]
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break
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}
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}
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if fv == nil {
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return nil
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}
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for _, b := range fn.Blocks {
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if used := Used(fv, b.Instrs); used != nil {
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return used
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}
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}
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return nil
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}
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