[Bug target/50313] New: ARM: PIC code references a non-existant label

[michael.hope at linaro dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50313

             Bug #: 50313
           Summary: ARM: PIC code references a non-existant label
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: michael.hope@linaro.org


Created attachment 25211
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25211
Preprocessed source

Building gmime with GCC 4.6.1 for ARM gives the following error:

michaelh@ursa1:~/linaro/bugs$ gcc -c -O2 -fPIC -save-temps gmime2.i
gmime2.s: Assembler messages:
gmime2.s:1007: Error: can't resolve `.rodata' {.rodata section} - `.LPIC18'
{*UND* section}

The assembler is correct - the code references a label which doesn't exist.

The suspicious code is around:
 bl g_hash_table_new(PLT)
 mov sl, r0
 add r0, sp, #32
 bl g_mime_decode_lwsp(PLT)
 ldr r3, .L146+24
 ldr r1, [sp, #4]
 str r3, [sp, #16]
 ldr r3, [sp, #32]
...
.L146:
...
 .word .LANCHOR0-(.LPIC18+4)

The 'ldr r3, .L146+24' references the offset. The value is spilt to the stack
before the normal `add r3, pc` and doesn't seem to be used afterwards.

The work-around is to compile at -O1 or -O3. The fault also exists in
gcc-4.6.1. It does not exist in gcc-4.5.3 or trunk r178025.

This is in a Cortex-A9+NEON+Thumb-2 configuration.