[PATCH v2] ld: testsuite: Simplify emulation check in libgot tests

[Rainer Orth]

Hi Maciej,

> On Sat, 24 Jan 2026, Rainer Orth wrote:
>
>> while I still like this approach because it allows to extend test
>> coverage to i386 ELF targets without -melf_i386, I primarily would like
>> to go this way to enable removing the non-*_sol2 emulations from native
>> Solaris gld.  They are never used outside of the ld testsuite, and I'd
>> rather test the native elf_i386_sol2 etc. emulations that *are* actually
>> used.
>> 
>> I guess I'll try this in ld-sparc first, where hardcoded
>> -melf32_sparc/elf64_sparc are only used 54 times, rather than
>> -melf_i386/elf_x86_64 (869 times).
>> 
>> I guess I'll try setting emul32/emul64 once in ld-lib.exp, then replace
>> all hardcoded instances of -m<emul> by $emul32/$emul64.
>
>  You might consider the MIPS approach where we also used to have an issue 
> with various targets using different emulations while still wanting to 
> verify non-default ones (legitimate for several MIPS targets) and came up 
> with an arrangement where the emulations selected are derived from the 
> target triplet.  Yes, it's a zoo, but so is the MIPS target collection.
>
>  See the `abi_ldflags' setting in ld/testsuite/ld-mips-elf/mips-elf.exp 
> for details.

my initial idea had been something like that.  However, I then noticed
that this would duplicate much of the information we already have in
ld/configure.tgt and thus the ld -V output.

My current idea runs like this: just set emul32/emul64 in ld-lib.exp
to the first emulation in ld -V that matches a given pattern.  E.g. on
Solaris/sparcv9 you get

GNU ld (GNU Binutils) 2.45.90.20260125
  Supported emulations:
   elf64_sparc_sol2
   elf32_sparc_sol2
   elf64_sparc
   elf32_sparc

For emul64 you'd pick the first emulation matching elf64_sparc.*,
i.e. elf64_sparc_sol2.  Similarly you get elf32_sparc_sol2 for emul32.

An implementation would look like this (completely untested):

global emul32 emul64
set emul32 unknown32
set emul64 unknown64

# Extract first emulation matching emul from ld_output.
#
proc ld_first_emul { emul ld_output } {
    if [regexp -line "$emul.*" $ld_output first_emul] then {
        return $first_emul
    }
}

# Determine primary 32 and 64-bit emulations from ld -V.
#
# Only introduce special cases as overrides.
# Maybe introduce secondary matches?

proc set_ld_emuls { } {
    global ld

    set ld_output [remote_exec host $ld "-V"]
    set ld_output [lindex $ld_output 1]
     
    switch -glob "$target" {
        i?86-*-* -
	x86_64-*-* {
	    set emul32 [ld_first_emul "elf32_sparc" $ld_output]
	    set emul64 [ld_first_emul "elf64_sparc" $ld_output]
	}
        sparc*-*-* {
	    set emul32 [ld_first_emul "elf32_sparc" $ld_output]
	    set emul64 [ld_first_emul "elf64_sparc" $ld_output]
    	}
}

This way, you'd always prefer the native emulations, not a hardcoded one
like elf32_sparc.  The latter is only used in the ld testsuite, while
gcc always uses elf32_sparc_sol2.  I'm not interested in test results
that don't match actual use.  Those are irrelevant IMO.

	Rainer

-- 
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Rainer Orth, Center for Biotechnology, Bielefeld University