grub-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH] Ensure that MIPS target code is compiled for the O32 ABI.


From: Andrei Borzenkov
Subject: Re: [PATCH] Ensure that MIPS target code is compiled for the O32 ABI.
Date: Sun, 23 Aug 2015 12:51:13 +0300
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0

22.08.2015 21:04, Mark H Weaver пишет:
Andrei Borzenkov <address@hidden> writes:

19.08.2015 21:35, Mark H Weaver пишет:
Include -mabi=32 in CFLAGS_PLATFORM and CCASFLAGS_PLATFORM to compile
code for the O32 ABI when targetting MIPS, since the MIPS assembly code
in GRUB assumes this.  This flag is also needed when compiling
asm-tests/mips.S from configure, because GNU as rejects MIPS register
names such as $t2 unless the O32 ABI is selected.

BTW, I assume this did work at some point; so this needs more verbose explanation what changed and why it stopped working.

---
   conf/Makefile.common | 4 ++++
   configure.ac         | 7 +++++--
   2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/conf/Makefile.common b/conf/Makefile.common
index fcb8d2e..bd125da 100644
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -20,6 +20,10 @@ endif
   if COND_powerpc_ieee1275
     CFLAGS_PLATFORM += -mcpu=powerpc
   endif
+if COND_mips
+  CFLAGS_PLATFORM += -mabi=32
+  CCASFLAGS_PLATFORM = -mabi=32
+endif


Does it work with clang?

Based on the error message below, clang seems to accept and understand
the -mabi=32 option, but the version of clang that we have in GNU Guix
(which uses the N32 ABI on MIPS) seems to lack support for compiling for
O32:

   address@hidden:~$ clang -mabi=32 mips.S
   error: unknown target CPU 'mips32r2'


Are you on native MIPS platform or cross-compiling? Which clang version? This works for me using current upstream clang (I do not have cross binutils so linking fails, but that's different story).

address@hidden:~/build/grub$ ~/build/llvm/bin/clang --target=mips -mabi=32 -v -integrated-as -c asm-tests/mips.S clang version 3.8.0 (git://github.com/llvm-mirror/clang.git 2b06a033d151865ca944dedf899e9b36aa630f42) (git://github.com/llvm-mirror/llvm.git 8f7e8462cdf3b0eed913202b81f14e2fead62be4)
Target: mips
Thread model: posix
InstalledDir: /home/bor/build/llvm/bin
"/home/bor/build/llvm/bin/clang-3.8" -cc1 -triple mips -E -disable-free -main-file-name mips.S -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -mconstructor-aliases -target-cpu mips32r2 -target-abi o32 -mfloat-abi hard -v -dwarf-column-info -coverage-file /home/bor/build/grub/mips.S -resource-dir /home/bor/build/llvm/bin/../lib/clang/3.8.0 -fdebug-compilation-dir /home/bor/build/grub -ferror-limit 19 -fmessage-length 95 -mstackrealign -fobjc-runtime=gcc -fdiagnostics-show-option -o /tmp/mips-b9949a.s -x assembler-with-cpp asm-tests/mips.S clang -cc1 version 3.8.0 based upon LLVM 3.8.0svn default target x86_64-unknown-linux-gnu
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /home/bor/build/llvm/bin/../lib/clang/3.8.0/include
 /usr/include
End of search list.
"/home/bor/build/llvm/bin/clang-3.8" -cc1as -triple mips -filetype obj -main-file-name mips.S -target-cpu mips32r2 -fdebug-compilation-dir /home/bor/build/grub -dwarf-debug-producer clang version 3.8.0 (git://github.com/llvm-mirror/clang.git 2b06a033d151865ca944dedf899e9b36aa630f42) (git://github.com/llvm-mirror/llvm.git 8f7e8462cdf3b0eed913202b81f14e2fead62be4) -mrelocation-model static -target-abi o32 -o mips.o /tmp/mips-b9949a.s

Actually this works for me also without -mabi=32 and produced object type is identical

However, it doesn't work without that option either:

   address@hidden:~$ clang mips.S
   mips.S: Assembler messages:
   mips.S:7: Error: invalid operands `ld $t2,0($t6)'
   mips.S:10: Error: invalid operands `addiu $t7,$s0,(b-a)'
   clang-3.6: error: assembler command failed with exit code 1 (use -v to see 
invocation)

This is the same failure that occurs with gcc when configured to use the
N32 ABI by default.  I also tried passing -fno-integrated-as in both
cases above, but it made no difference.

       Mark





reply via email to

[Prev in Thread] Current Thread [Next in Thread]