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compiler: do not emit RET twice for nested BlockStmt

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When function finishes with `*ast.BlockStmt`, last return
in that block should be looked for.
This commit is contained in:
Evgeniy Stratonikov 2021-02-05 14:31:45 +03:00
parent 6445e4be91
commit 1f238ce6fd
2 changed files with 11 additions and 5 deletions
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14
pkg/compiler/analysis.go
View file

@ -175,10 +175,16 @@ func (f funcUsage) funcUsed(name string) bool {
}
// lastStmtIsReturn checks if last statement of the declaration was return statement..
func lastStmtIsReturn(decl *ast.FuncDecl) (b bool) {
if l := len(decl.Body.List); l != 0 {
_, ok := decl.Body.List[l-1].(*ast.ReturnStmt)
return ok
func lastStmtIsReturn(body *ast.BlockStmt) (b bool) {
if l := len(body.List); l != 0 {
switch inner := body.List[l-1].(type) {
case *ast.BlockStmt:
return lastStmtIsReturn(inner)
case *ast.ReturnStmt:
return true
default:
return false
}
}
return false
}

2
pkg/compiler/codegen.go
View file

@ -440,7 +440,7 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
// If we have reached the end of the function without encountering `return` statement,
// we should clean alt.stack manually.
// This can be the case with void and named-return functions.
if !isInit && !isDeploy && !lastStmtIsReturn(decl) {
if !isInit && !isDeploy && !lastStmtIsReturn(decl.Body) {
c.saveSequencePoint(decl.Body)
emit.Opcodes(c.prog.BinWriter, opcode.RET)
}