Commit 537baf3e authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

Filter: Fix bug in variable shadowing 

When a new variable used the same name as an existing symbol in an outer
scope, then offset number was defined based on a scope of the existing
symbol ($3) instead of a scope of the new symbol (sym_). That can lead
to two variables sharing the same memory slot.
parent 23cf8498

filter/config.Y

+3 −3
Original line number Diff line number Diff line
@@ -408,7 +408,7 @@ function_argsn: 
 | function_argsn type symbol ';' {

     if ($3->scope->slots >= 0xfe) cf_error("Too many declarations, at most 255 allowed");

     $$ = cfg_alloc(sizeof(struct f_arg));

     $$->arg = cf_define_symbol($3, SYM_VARIABLE | $2, offset, $3->scope->slots++);

     $$->arg = cf_define_symbol($3, SYM_VARIABLE | $2, offset, sym_->scope->slots++);

     $$->next = $1;

   }

 ;
@@ -417,7 +417,7 @@ function_args: 
   '(' ')' { $$ = NULL; }

 | '(' function_argsn type symbol ')' {

     $$ = cfg_alloc(sizeof(struct f_arg));

     $$->arg = cf_define_symbol($4, SYM_VARIABLE | $3, offset, $4->scope->slots++);

     $$->arg = cf_define_symbol($4, SYM_VARIABLE | $3, offset, sym_->scope->slots++);

     $$->next = $2;

   }

 ;
@@ -425,7 +425,7 @@ function_args: 
function_vars:

   /* EMPTY */ { $$ = 0; }

 | function_vars type symbol ';' {

     cf_define_symbol($3, SYM_VARIABLE | $2, offset, $3->scope->slots++);

     cf_define_symbol($3, SYM_VARIABLE | $2, offset, sym_->scope->slots++);

     $$ = $1 + 1;

   }

 ;

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