Thread overview
[Issue 3049] New: ICE(cod4.c) or segfault: Array operation on void[] array
Jun 11, 2009
Don
Oct 06, 2009
Walter Bright
June 03, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3049

           Summary: ICE(cod4.c) or segfault: Array operation on void[]
                    array
           Product: D
           Version: 1.045
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: diagnostic, ice-on-invalid-code, patch
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: clugdbug@yahoo.com.au


Array operations involving void[] can either ICE in the backend, segfault in the front-end, or generate error messages without line numbers, which refer to compiler-generated code. All have the same root cause: such operations are nonsensical.

PATCH(tested on DMD1.045+D2.030): Add this code to the start of
BinExp::arrayOp(Scope *) in arrayop.c.
---
    if (type == Type::terror) { return this; }
    if (type->toBasetype()->nextOf()->toBasetype()->ty==Tvoid) {
        error("Cannot perform array operations on void[] arrays");
        return this;
    }
---

// TEST CASE 1: error message with no line number, referring to
// compiler-generated code. The error is so unhelpful, it might
// as well be an ICE.
// Error: 'p0[p]' is not of arithmetic type, it is a const(void)
// Error: expression -(p0[p]) is void and has no value

void bar(){
  void [] x;
  x[] = -x[];
}

// TEST CASE 2: ICE(backend/cod4.c 353). On D1, it is another
// error message with no line number
void foo(T)() {
   T[] a;
   a[] = -a[];
}
void main(){
 foo!(void)();
}

// Test case 3: segfault D1 + D2
typedef void car;
void baz(){
  int [] x;
  car [] y;
  y[] = -x[];
}

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--- Comment #1 from Don <clugdbug@yahoo.com.au>  2009-06-10 17:31:43 PDT ---
There was a bug in the patch I posted, it assumed that Type::terror is a unique
type whereas it is currently the same as Tint32.
Fortunately, that line was not necessary anyway (it would just result in nicer
error messages).

PATCH: Add this code to the start of
BinExp::arrayOp(Scope *) in arrayop.c.
---
    if (type->toBasetype()->nextOf()->toBasetype()->ty==Tvoid) {
        error("Cannot perform array operations on void[] arrays");
        return this;
    }
---

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Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> 2009-10-06 02:16:33 PDT ---
Fixed dmd 1.048 and 2.033

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