Re: [PATCH] Fix gdb.dwarf2/dw2-dir-file-name.exp test for MIPS architectures

Pedro Alves
2014-10-17T12:07:15Z

On 10/11/2014 10:01 PM, Kwok Cheung Yeung wrote:
> This patch fixes the failures that occur with the
> gdb.dwarf2/dw2-dir-file-name.exp test on 64-bit MIPS and compressed MIPS
> ISAs (i.e. MIPS16 and microMIPS).
>
> The failures on 64-bit occur because the generated DWARF address
> information is always 32-bit, which causes the upper 32-bits of
> addresses to be truncated and causes breakpoints to be set on the wrong
> address if any of the upper 32-bits are non-zero. I suspect that other
> 64-bit architectures get away with it because they place all their
> instructions at a VMA lower than 2^32 by default. This patch causes
> 64-bit addresses to be generated if a 64-bit target is detected.
>
> The failures on MIPS16 and microMIPS occur because the breakpoint
> address needs to have the LSB set to 1 (used to indicate that the code
> is compressed). However, the function name is interpreted as a data
> label, causing GDB to set breakpoints at even addresses. This is fixed
> by explicitly adding a '.insn' directive (see
> https://sourceware.org/binutils/docs/as/MIPS-insn.html) after the label
> on MIPS only.

Looks fine to me, but I'd like to hear Maciej's OK on the MIPS specifics too.

Please make sure x86_64 still works.

I wonder if this test could be simplified using the testsuite's dwarf
assembler (Dwarf::assemble).

>
> Kwok
>
> 2014-08-14 Kwok Cheung Yeung <kcy@codesourcery.com>
>
> gdb/testsuite/
> * gdb.dwarf2/dw2-dir-file-name.exp (addr_len): New.
> (out_cu): Use addr_len for the size of addresses.
> (out_line): Likewise. Size DW_LNE_set_address instruction
> according to addr_len.
> * gdb.dwarf2/dw2-dir-file-name.c (START_INSNS): New.
> (FUNC): Add START_INSNS to definition.
>

Thanks,
Pedro Alves