[dmd-internals] CTFE problem - need debugging hint

[Don Clugston]

On 2 January 2013 17:44, Kai Nacke <kai.nacke at redstar.de> wrote:
> Hi!
>
> While trying to port LDC to PPC64 I ran into the following CTFE issue. This
> small program (reduced from std.conv.to!string(int)):
>
> import core.stdc.stdio : printf;
>
> string toStr()
> {
>     char x[];
>     x.length = 16;
>     x[0..3] = "666";
>     x.length = 3;
>     return cast(string) x;
> }
>
> string gencode()
> {
>     return "int x = " ~ toStr ~ ";";
> }
>
> void main()
> {
>     mixin(gencode());
>     printf("Value of gencode: |%s|\n", gencode().ptr);
> }
>
> produces the error:
> bug2.d(19): Error: expression expected, not 'EOF'
> bug2.d(19): Error: semicolon expected, not 'EOF'
> (the mixin statement is in line 19)
>
> From the log I conclude that it must have something to do with the split
> range and array join:
>
> bug2.d(8) VarExp::interpret() x
> REF ASSIGN: x=['6', '6', '6']
> ARRAY LITERAL type=char[] 0x10011b59040:
>  void
>  void
>  void
> bug2.d(9) ReturnStatement::interpret(cast(string)x)
> bug2.d(9) CastExp::interpret() cast(string)x
> bug2.d(9) VarExp::interpret() x
> RETURN bug2.d(9)
> ARRAY LITERAL type=char[] 0x10011b59040:
>  void
>  void
>  void

Something has gone wrong by this point. x is still [void, void, void],
when it should be ['6','6','6'].
Looks as though the assignment didn't happen properly.

> Does anybody have a hint how  I can reduce this further? E.g. is there a way
> to view the content of the array?

showCtfeExpr(arr).

Probably you can get a reduced test case like
static assert(toStr()=="666");
I don't think the mixin bit is relevant, unless it's a compilation order issue.


>
> Thanks in advance.
>
> Kai
>
>
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