compiler: refactor void calls processing

Call result is not used only if it occurs inside a `ExprStmt`.
Otherwise (`IfStmt`, `BinExpr`...) it is used.

Fix #1495.
This commit is contained in:
Evgenii Stratonikov 2020-10-19 10:43:45 +03:00
parent 6849499f56
commit 01ccaefe2f
2 changed files with 13 additions and 66 deletions

View file

@ -90,73 +90,11 @@ func (c *codegen) getFuncNameFromDecl(pkgPath string, decl *ast.FuncDecl) string
// analyzeVoidCalls checks for functions that are not assigned
// and therefore we need to cleanup the return value from the stack.
func (c *funcScope) analyzeVoidCalls(node ast.Node) bool {
switch n := node.(type) {
case *ast.AssignStmt:
for i := 0; i < len(n.Rhs); i++ {
switch n.Rhs[i].(type) {
case *ast.CallExpr:
return false
}
}
case *ast.ReturnStmt:
if len(n.Results) > 0 {
switch n.Results[0].(type) {
case *ast.CallExpr:
return false
}
}
case *ast.TypeAssertExpr:
ce, ok := n.X.(*ast.CallExpr)
est, ok := node.(*ast.ExprStmt)
if ok {
ce, ok := est.X.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
case *ast.BinaryExpr:
return false
case *ast.RangeStmt:
ce, ok := n.X.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
case *ast.UnaryExpr:
ce, ok := n.X.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
case *ast.IfStmt:
// we can't just return `false`, because we still need to process body
ce, ok := n.Cond.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
case *ast.SwitchStmt:
ce, ok := n.Tag.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
case *ast.CaseClause:
for _, e := range n.List {
ce, ok := e.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
}
case *ast.CallExpr:
_, ok := c.voidCalls[n]
if !ok {
c.voidCalls[n] = true
}
return false
case *ast.CompositeLit:
for _, e := range n.Elts {
switch val := e.(type) {
case *ast.CallExpr: // slice
c.voidCalls[val] = false
case *ast.KeyValueExpr: // struct and map
ce, ok := val.Value.(*ast.CallExpr)
if ok {
c.voidCalls[ce] = false
}
}
c.voidCalls[ce] = true
}
}
return true

View file

@ -86,6 +86,15 @@ func TestNotAssignedFunctionCall(t *testing.T) {
}`
eval(t, src, big.NewInt(42))
})
t.Run("VarDecl", func(t *testing.T) {
src := `package foo
func foo() []int { return []int{1} }
func Main() int {
var x = foo()
return len(x)
}`
eval(t, src, big.NewInt(1))
})
}
func TestMultipleFunctionCalls(t *testing.T) {