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compiler: process nil comparisons separately

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This commit is contained in:
Evgenii Stratonikov 2020-08-23 12:33:21 +03:00
parent e4af295080
commit ae88c77a8a
1 changed files with 20 additions and 21 deletions
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41
pkg/compiler/codegen.go
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@ -702,6 +702,15 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
return nil
}
if arg := c.getCompareWithNilArg(n); arg != nil {
ast.Walk(c, arg)
emit.Opcode(c.prog.BinWriter, opcode.ISNULL)
if n.Op == token.NEQ {
emit.Opcode(c.prog.BinWriter, opcode.NOT)
}
return nil
}
switch n.Op {
case token.LAND:
end := c.newLabel()
@ -724,27 +733,8 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
return nil
default:
var checkForNull bool
if isExprNil(n.X) {
checkForNull = true
} else {
ast.Walk(c, n.X)
}
if isExprNil(n.Y) {
checkForNull = true
} else {
ast.Walk(c, n.Y)
}
if checkForNull {
emit.Opcode(c.prog.BinWriter, opcode.ISNULL)
if n.Op == token.NEQ {
emit.Opcode(c.prog.BinWriter, opcode.NOT)
}
return nil
}
ast.Walk(c, n.X)
ast.Walk(c, n.Y)
switch {
case n.Op == token.ADD:
// VM has separate opcodes for number and string concatenation
@ -1149,6 +1139,15 @@ func isFallthroughStmt(c ast.Node) bool {
return ok && s.Tok == token.FALLTHROUGH
}
func (c *codegen) getCompareWithNilArg(n *ast.BinaryExpr) ast.Expr {
if isExprNil(n.X) {
return n.Y
} else if isExprNil(n.Y) {
return n.X
}
return nil
}
func (c *codegen) pushStackLabel(name string, size int) {
c.labelList = append(c.labelList, labelWithStackSize{
name: name,