func rewriteStmt(stmt *cc.Stmt) {
// TODO: Double-check stmt.Labels
switch stmt.Op {
case cc.ARGBEGIN:
panic(fmt.Sprintf("unexpected ARGBEGIN"))
case cc.Do:
// Rewrite do { ... } while(x)
// to for(;;) { ... if(!x) break }
// Since rewriteStmt is called in a preorder traversal,
// the recursion into the children will clean up x
// in the if condition as needed.
stmt.Op = cc.For
x := stmt.Expr
stmt.Expr = nil
stmt.Body = forceBlock(stmt.Body)
stmt.Body.Block = append(stmt.Body.Block, &cc.Stmt{
Op: cc.If,
Expr: &cc.Expr{Op: cc.Not, Left: x},
Body: &cc.Stmt{Op: cc.Break},
})
case cc.While:
stmt.Op = cc.For
fallthrough
case cc.For:
before1, _ := extractSideEffects(stmt.Pre, sideStmt|sideNoAfter)
before2, _ := extractSideEffects(stmt.Expr, sideNoAfter)
if len(before2) > 0 {
x := stmt.Expr
stmt.Expr = nil
stmt.Body = forceBlock(stmt.Body)
top := &cc.Stmt{
Op: cc.If,
Expr: &cc.Expr{Op: cc.Not, Left: x},
Body: &cc.Stmt{Op: cc.Break},
}
stmt.Body.Block = append(append(before2, top), stmt.Body.Block...)
}
if len(before1) > 0 {
old := copyStmt(stmt)
stmt.Pre = nil
stmt.Expr = nil
stmt.Post = nil
stmt.Body = nil
stmt.Op = c2go.BlockNoBrace
stmt.Block = append(before1, old)
}
before, after := extractSideEffects(stmt.Post, sideStmt)
if len(before)+len(after) > 0 {
all := append(append(before, &cc.Stmt{Op: cc.StmtExpr, Expr: stmt.Post}), after...)
stmt.Post = &cc.Expr{Op: c2go.ExprBlock, Block: all}
}
case cc.If, cc.Return:
before, _ := extractSideEffects(stmt.Expr, sideNoAfter)
if len(before) > 0 {
old := copyStmt(stmt)
stmt.Expr = nil
stmt.Body = nil
stmt.Else = nil
stmt.Op = c2go.BlockNoBrace
stmt.Block = append(before, old)
}
case cc.StmtExpr:
before, after := extractSideEffects(stmt.Expr, sideStmt)
if len(before)+len(after) > 0 {
old := copyStmt(stmt)
stmt.Expr = nil
stmt.Op = c2go.BlockNoBrace
stmt.Block = append(append(before, old), after...)
}
case cc.Goto:
// TODO: Figure out where the goto goes and maybe rewrite
// to labeled break/continue.
// Otherwise move code or something.
case cc.Switch:
// TODO: Change default fallthrough to default break.
before, _ := extractSideEffects(stmt.Expr, sideNoAfter)
rewriteSwitch(stmt)
if len(before) > 0 {
old := copyStmt(stmt)
stmt.Expr = nil
stmt.Body = nil
stmt.Else = nil
stmt.Op = c2go.BlockNoBrace
stmt.Block = append(before, old)
}
}
}
