Re: PATCH [1/n] X32: Add initial -x32 support

[Uros Bizjak <ubizjak@gmail.com>]

On Tue, Jul 5, 2011 at 7:54 PM, H.J. Lu <hjl.tools@gmail.com> wrote:

>>> I'd like to start submitting a series of patches to enable x32:
>>>
>>> https://sites.google.com/site/x32abi/
>>>
>>> The GCC x32 branch is very stable. There are no unexpected failures in
>>> C, C++, Fortran and Objective C testsuites.  SPEC CPU 2K/2006 compile
>>> and run correctly at -O2 and -O3.
>>>
>>> More than 90% of changes are in x86 backend.  I have submitted non-x86
>>> backend patches.  Most of them have been reviewed and checked in.  Only
>>> 4 patches are pending for review/approval.
>>>
>>> This is the first x86 backend patch to support x32.  By default, x32 is
>>> disabled and x32 run-time support isn't required.  OK for trunk?
>>
>> Please strip out --enable-ia32 stuff, it complicates things ATM.  I
>> assume that --enable-x32 applies only to 64bit targets, so this part


I think that better name of the file would be "t-linux64-x32".

@@ -2631,6 +2640,7 @@ esac
 case ${target} in
 i[34567]86-*-linux* | x86_64-*-linux*)
 	tmake_file="${tmake_file} i386/t-pmm_malloc i386/t-i386"
+	libgcc_tm_file="${libgcc_tm_file} i386/value-unwind.h"

Not yet.

@@ -58,25 +58,31 @@ see the files COPYING3 and COPYING.RUNTIME
respectively.  If not, see

 #if TARGET_64BIT_DEFAULT
 #define SPEC_32 "m32"
-#define SPEC_64 "!m32"
+#define SPEC_64 "m32|mx32:;"
+#define SPEC_X32 "mx32"
 #else
-#define SPEC_32 "!m64"
+#define SPEC_32 "m64|mx32:;"
 #define SPEC_64 "m64"
+#define SPEC_X32 "mx32"
 #endif

I really think that "!(m64|mx32)" is more descriptive and clear...

 #undef	LINK_SPEC
 #define LINK_SPEC "%{" SPEC_64 ":-m " GNU_USER_LINK_EMULATION64 "} \
                    %{" SPEC_32 ":-m " GNU_USER_LINK_EMULATION32 "} \
+                   %{" SPEC_X32 ":-m " GNU_USER_LINK_EMULATIONX32 "} \
   %{shared:-shared} \
   %{!shared: \
     %{!static: \
       %{rdynamic:-export-dynamic} \
       %{" SPEC_32 ":-dynamic-linker " GNU_USER_DYNAMIC_LINKER32 "} \
-      %{" SPEC_64 ":-dynamic-linker " GNU_USER_DYNAMIC_LINKER64 "}} \
+      %{" SPEC_64 ":-dynamic-linker " GNU_USER_DYNAMIC_LINKER64 "} \
+      %{" SPEC_X32 ":-dynamic-linker " GNU_USER_DYNAMIC_LINKERX32 "}} \
     %{static:-static}}"

On the border of bikesheding, GNU_USER_LINK_EMULATION64_X32 and
GNU_USER_DYNAMIC_LINKER64_X32 sounds better to me.

Same with the below:

+#define GLIBC_DYNAMIC_LINKERX32 "/libx32/ld-linux-x32.so.2"
+#define UCLIBC_DYNAMIC_LINKERX32 "/lib/ldx32-uClibc.so.0"
+#define BIONIC_DYNAMIC_LINKERX32 "/system/bin/linkerx32"

+++ b/gcc/config/i386/t-linux-x32

Please rename above file to t-linux64-x32.

With above small changes, the patch looks OK to me. Please also wait
for build and options maintainer (CC'd) approvals.

Thanks,
Uros.