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compiler: check for NULL when calculating len(), fix #1153

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This commit is contained in:
Roman Khimov 2020-07-07 21:49:21 +03:00
parent b3e450477d
commit ebe37d1a46
2 changed files with 19 additions and 1 deletions
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9
pkg/compiler/codegen.go
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@ -1173,7 +1173,13 @@ func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
switch name {
case "len":
emit.Opcode(c.prog.BinWriter, opcode.DUP)
emit.Opcode(c.prog.BinWriter, opcode.ISNULL)
emit.Instruction(c.prog.BinWriter, opcode.JMPIF, []byte{2 + 1 + 2})
emit.Opcode(c.prog.BinWriter, opcode.SIZE)
emit.Instruction(c.prog.BinWriter, opcode.JMP, []byte{2 + 1 + 1})
emit.Opcode(c.prog.BinWriter, opcode.DROP)
emit.Opcode(c.prog.BinWriter, opcode.PUSH0)
case "append":
arg := expr.Args[0]
typ := c.typeInfo.Types[arg].Type
@ -1515,7 +1521,8 @@ func (c *codegen) writeJumps(b []byte) error {
case opcode.JMP, opcode.JMPIFNOT, opcode.JMPIF, opcode.CALL,
opcode.JMPEQ, opcode.JMPNE,
opcode.JMPGT, opcode.JMPGE, opcode.JMPLE, opcode.JMPLT:
panic("short jumps are not yet supported")
// Noop, assumed to be correct already. If you're fixing #905,
// make sure not to break "len" handling above.
case opcode.JMPL, opcode.JMPIFL, opcode.JMPIFNOTL,
opcode.JMPEQL, opcode.JMPNEL,
opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLEL, opcode.JMPLTL,

11
pkg/compiler/interop_test.go
View file

@ -187,3 +187,14 @@ func TestBuiltinPackage(t *testing.T) {
}`
eval(t, src, big.NewInt(1))
}
func TestLenForNil(t *testing.T) {
src := `
package foo
func Main() bool {
var a []int = nil
return len(a) == 0
}`
eval(t, src, true)
}