[LLVMdev] Debug info failing in assembler.

Richard Pennington rich at pennware.com
Sat Sep 21 05:52:44 PDT 2013


I just updated from r190763 to r191137 and started getting failures in 
generated assembly language when debug info is enabled. Here is the test 

// Compile and run for every target.
// RUN: %ecc -g -o %t %s && %t
// FAIL: %armecc -g -o %t %s && %armrun %t
// FAIL: %armebecc -g -o %t %s && %armebrun %t
// RUN: %i386ecc -g -o %t %s && %i386run %t
// FAIL: %microblazeecc -g -o %t %s && %microblazerun %t
// FAIL: %mipsecc -g -o %t %s && %mipsrun %t
// FAIL: %mipselecc -g -o %t %s && %mipselrun %t
// FAIL: %ppcecc -g -o %t %s && %ppcrun %t
// FAIL: %ppc64ecc -g -o %t %s && %ppc64run %t
// RUN: %x86_64ecc -g -o %t %s && %x86_64run %t

int comm;
int main()
     comm = 6;

This fails on all but the x86 processors. The typical failure looks like 
         .type   comm, at object            # @comm
         .comm   comm,4,4
         .cfi_sections .debug_frame
         .section        .debug_aranges,"", at progbits
         .long   36                      # Length of ARange Set
         .short  2                       # DWARF Arange version number
         .long   .L.debug_info_begin0    # Offset Into Debug Info Section
         .byte   4                       # Address Size (in bytes)
         .byte   0                       # Segment Size (in bytes)
         .byte   255
         .byte   255
         .byte   255
         .byte   255
         .long   comm
.Lset0 = .L.bss_end-comm
         .long   .Lset0

The typical error message is:
/tmp/debug-8ecf9d.s: Assembler messages:
/tmp/debug-8ecf9d.s: Error: invalid operands (.bss and *COM* sections) 
for `-' when setting `.Lset0'

Is it legal to mix .comm symbols and .bss symbols in assembly? Is the 
x86 success a bug or a feature?


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