[LLVMbugs] [Bug 82] New: LLVM cannot handle structures with more than 256 elements

[bugzilla-daemon at zion.cs.uiuc.edu]

http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=82

           Summary: LLVM cannot handle structures with more than 256
                    elements
           Product: libraries
           Version: 1.0
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Core LLVM classes
        AssignedTo: sabre at nondot.org
        ReportedBy: sabre at nondot.org


Currently, the getelementptr instruction uses constant 'ubyte' indexes to index
into structure fields.  This means that we can't address more than 2^8 fields.

The fix for this is to change the ubyte index to be a ulong.  Doing this however
will require auditing all of LLVM, looking for passes walking getelementptrs. 
Also, we'll have to bump the bytecode version to have the readers autotranslate
the indexes.

This is certainly not an impossible thing to fix: in fact it's been on my TODO
list for a long time now - it's just that it will take time.  The urgency of
fixing this is now greater than before, however, because it turns out that X
uses large structures, making compilation of X programs unlikely to work out if
they use the "wrong" structures.  This should be fixed for the 1.1 release.

-Chris



------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.