[PATCH] PowerPC: incorrect library search order?

[Alexey Neyman]

Hi,

The problem below resulted in failures of some PowerPC sample toolchains 
in crosstool-ng.

As far as I understand, the code in ld/emulparams/elf32ppccommon.sh 
attempts to use /lib32 or /lib64 if the endianness of the selected 
emulation matches the endianness of the machine, and use the directories 
with explicit endianness (such as /lib32le, /lib32be, /lib64le, 
/lib64be) otherwise. However, there are two issues with that code:

First, it checks for *host's* triplet, not target. The host may not be 
using 'le' suffix to designate its endianness - for example, it may be 
little-endian by default. It also doesn't seem to make much sense to 
check the host for default layout - why would the expected sysroot 
layout on a big-endian host differ from that on a little-endian host?

Second, the check itself is flawed: it should be checking just the CPU 
part of the triplet, not the whole string. In its current form, the 
check compares $host against "*le-*" pattern - which matches 
"x86_64-apple-darwin16.0".

This results in ld configured for powerpc64le-unknown-linux target on 
x86_64-unknown-linux host behaving as follows:
- without -m, or with -melf64lppc it searches /lib64le first
- with '-melf64ppc' it searches /lib64 first - which seems to run 
counter to the intended purpose of that code, as the target is 
configured as little-endian!

'ld' works ok with libraries in /lib (which is always searched as the 
last fallback, regardless of the host and selected emulation). Once the 
libraries are placed in /lib64 (default gcc's directory for this 
target), ld fails to find them.

This erroneous code first appeared in binutils 2.24.

Patch attached.

Regards,
Alexey.



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