[v1,0/7] Add LoongArch support.

  This is a series of patch sets to support LoongArch.

The LoongArch architecture (LoongArch) is an Instruction Set
Architecture (ISA) that has a Reduced Instruction Set Computer (RISC)
style.
The documents are on
https://loongson.github.io/LoongArch-Documentation/README-EN.html

The ELF ABI Documents are on:
https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html

The binutils has been merged into trunk:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=560b3fe208255ae909b4b1c88ba9c28b09043307

The ABI -mabi=name is still under discussion and may change in the next version, 
the rest can be reviewed.

chenglulu (7):
  LoongArch Port: gcc
  LoongArch Port: Regenerate gcc/configure.
  LoongArch Port: libgcc
  LoongArch Port: Regenerate libgcc/configure.
  LoongArch Port: libgomp
  LoongArch Port: gcc/testsuite
  LoongArch Port: Regenerate configure

 config/picflag.m4                             |    3 +
 configure                                     |   12 +-
 configure.ac                                  |   10 +-
 .../config/loongarch/loongarch-common.c       |   63 +
 gcc/config.gcc                                |  248 +-
 gcc/config/host-linux.c                       |    2 +
 gcc/config/loongarch/constraints.md           |  212 +
 gcc/config/loongarch/generic.md               |  132 +
 gcc/config/loongarch/gnu-user.h               |   86 +
 gcc/config/loongarch/la464.md                 |  132 +
 gcc/config/loongarch/larchintrin.h            |  413 ++
 gcc/config/loongarch/linux.h                  |   57 +
 gcc/config/loongarch/loongarch-builtins.c     |  511 ++
 gcc/config/loongarch/loongarch-c.c            |  137 +
 gcc/config/loongarch/loongarch-cpu.c          |  182 +
 gcc/config/loongarch/loongarch-cpu.h          |   55 +
 gcc/config/loongarch/loongarch-cpucfg.h       |   29 +
 gcc/config/loongarch/loongarch-driver.c       |  201 +
 gcc/config/loongarch/loongarch-driver.h       |   49 +
 gcc/config/loongarch/loongarch-ftypes.def     |   95 +
 gcc/config/loongarch/loongarch-modes.def      |   35 +
 gcc/config/loongarch/loongarch-opts.c         |  311 +
 gcc/config/loongarch/loongarch-opts.h         |  133 +
 gcc/config/loongarch/loongarch-protos.h       |  244 +
 gcc/config/loongarch/loongarch-rtx-cost.h     |   80 +
 gcc/config/loongarch/loongarch.c              | 6485 +++++++++++++++++
 gcc/config/loongarch/loongarch.h              | 1292 ++++
 gcc/config/loongarch/loongarch.md             | 3836 ++++++++++
 gcc/config/loongarch/loongarch.opt            |  206 +
 gcc/config/loongarch/predicates.md            |  553 ++
 gcc/config/loongarch/sync.md                  |  614 ++
 gcc/config/loongarch/t-linux                  |   51 +
 gcc/config/loongarch/t-loongarch              |   46 +
 gcc/configure                                 |   63 +-
 gcc/configure.ac                              |   33 +-
 gcc/doc/invoke.texi                           |  193 +
 gcc/doc/md.texi                               |   55 +
 gcc/testsuite/g++.dg/cpp0x/constexpr-rom.C    |    2 +-
 gcc/testsuite/g++.old-deja/g++.abi/ptrmem.C   |    2 +-
 gcc/testsuite/g++.old-deja/g++.pt/ptrmem6.C   |    2 +-
 gcc/testsuite/gcc.dg/20020312-2.c             |    2 +
 gcc/testsuite/gcc.dg/loop-8.c                 |    2 +-
 .../torture/stackalign/builtin-apply-2.c      |    2 +-
 gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-3.c     |    2 +-
 .../gcc.target/loongarch/loongarch.exp        |   40 +
 .../gcc.target/loongarch/tst-asm-const.c      |   16 +
 gcc/testsuite/go.test/go-test.exp             |    3 +
 gcc/testsuite/lib/target-supports.exp         |   14 +
 libgcc/config.host                            |   26 +
 libgcc/config/loongarch/crtfastmath.c         |   52 +
 libgcc/config/loongarch/crti.S                |   43 +
 libgcc/config/loongarch/crtn.S                |   39 +
 libgcc/config/loongarch/lib2funcs.c           |    0
 libgcc/config/loongarch/linux-unwind.h        |   80 +
 libgcc/config/loongarch/sfp-machine.h         |  152 +
 libgcc/config/loongarch/t-crtstuff            |    2 +
 libgcc/config/loongarch/t-elf                 |    3 +
 libgcc/config/loongarch/t-loongarch           |    9 +
 libgcc/config/loongarch/t-loongarch64         |    1 +
 libgcc/config/loongarch/t-softfp-tf           |    3 +
 libgcc/configure                              |    2 +-
 libgcc/configure.ac                           |    2 +-
 libgomp/configure.tgt                         |    4 +
 63 files changed, 17343 insertions(+), 21 deletions(-)
 create mode 100644 gcc/common/config/loongarch/loongarch-common.c
 create mode 100644 gcc/config/loongarch/constraints.md
 create mode 100644 gcc/config/loongarch/generic.md
 create mode 100644 gcc/config/loongarch/gnu-user.h
 create mode 100644 gcc/config/loongarch/la464.md
 create mode 100644 gcc/config/loongarch/larchintrin.h
 create mode 100644 gcc/config/loongarch/linux.h
 create mode 100644 gcc/config/loongarch/loongarch-builtins.c
 create mode 100644 gcc/config/loongarch/loongarch-c.c
 create mode 100644 gcc/config/loongarch/loongarch-cpu.c
 create mode 100644 gcc/config/loongarch/loongarch-cpu.h
 create mode 100644 gcc/config/loongarch/loongarch-cpucfg.h
 create mode 100644 gcc/config/loongarch/loongarch-driver.c
 create mode 100644 gcc/config/loongarch/loongarch-driver.h
 create mode 100644 gcc/config/loongarch/loongarch-ftypes.def
 create mode 100644 gcc/config/loongarch/loongarch-modes.def
 create mode 100644 gcc/config/loongarch/loongarch-opts.c
 create mode 100644 gcc/config/loongarch/loongarch-opts.h
 create mode 100644 gcc/config/loongarch/loongarch-protos.h
 create mode 100644 gcc/config/loongarch/loongarch-rtx-cost.h
 create mode 100644 gcc/config/loongarch/loongarch.c
 create mode 100644 gcc/config/loongarch/loongarch.h
 create mode 100644 gcc/config/loongarch/loongarch.md
 create mode 100644 gcc/config/loongarch/loongarch.opt
 create mode 100644 gcc/config/loongarch/predicates.md
 create mode 100644 gcc/config/loongarch/sync.md
 create mode 100644 gcc/config/loongarch/t-linux
 create mode 100644 gcc/config/loongarch/t-loongarch
 create mode 100644 gcc/testsuite/gcc.target/loongarch/loongarch.exp
 create mode 100644 gcc/testsuite/gcc.target/loongarch/tst-asm-const.c
 create mode 100644 libgcc/config/loongarch/crtfastmath.c
 create mode 100644 libgcc/config/loongarch/crti.S
 create mode 100644 libgcc/config/loongarch/crtn.S
 create mode 100644 libgcc/config/loongarch/lib2funcs.c
 create mode 100644 libgcc/config/loongarch/linux-unwind.h
 create mode 100644 libgcc/config/loongarch/sfp-machine.h
 create mode 100644 libgcc/config/loongarch/t-crtstuff
 create mode 100644 libgcc/config/loongarch/t-elf
 create mode 100644 libgcc/config/loongarch/t-loongarch
 create mode 100644 libgcc/config/loongarch/t-loongarch64
 create mode 100644 libgcc/config/loongarch/t-softfp-tf
  

On Sat, 2021-11-06 at 16:40 +0800, Chenghua Xu wrote:
> 
> This is a series of patch sets to support LoongArch.
> 
> The LoongArch architecture (LoongArch) is an Instruction Set
> Architecture (ISA) that has a Reduced Instruction Set Computer (RISC)
> style.
> The documents are on
> https://loongson.github.io/LoongArch-Documentation/README-EN.html
> 
> The ELF ABI Documents are on:
> https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html
> 
> The binutils has been merged into trunk:
> https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=560b3fe208255ae909b4b1c88ba9c28b09043307

Congratulations!

> The ABI -mabi=name is still under discussion and may change in the
> next version, 
> the rest can be reviewed.
> 
> chenglulu (7):
>   LoongArch Port: gcc

The [PATCH 1/1] does not arrive at gcc-patches successfully.  I guess
it's because of some mail size limit issue...  According to
https://gcc.gnu.org/contribute.html:

> If the patch is too big or too mechanical, posting it gzipped or
> bzip2ed and uuencoded or encoded as a base64 MIME part is acceptable,
> as long as the ChangeLog is still posted as plain text.
  

This patch does not arrive at  mail list. Send as an attachment in a 
compressed format.
  

On Mon, 2021-11-08 at 10:30 +0800, Chenghua Xu wrote:
> This patch does not arrive at  mail list. Send as an attachment in a 
> compressed format.

I think .patch.gz is perferred instead of .tar.gz.

And is it possible to seperate this into multiple commits?  For example
the whole "-march=native" support can be in a seperate commit.  It will
be easier to review those changes one-by-one.

> --- /dev/null
> +++ b/gcc/config/loongarch/linux.h
/* snip */
> +  /* Integer ABI  */
> +  #if DEFAULT_ABI_INT == ABI_LP64
> +    #define INT_ABI_SUFFIX "lib64"
> +  #endif

"INT_ABI_SUFFIX" should be renamed to INT_ABI_LIBDIR or something. 
"lib64" is not a "suffix".

> --- /dev/null
> +++ b/gcc/config/loongarch/loongarch-opts.c
/* snip */

> +  /* 5.  Check integer ABI-ISA for conflicts.  */
> +  switch (*isa_int)
> +    {
> +    case ISA_LA64:
> +      if (*abi_int != ABI_LP64) goto error_int_abi;
> +      break;

/* snip */

> +      switch (*isa_float)
> +       {
> +       case ISA_SOFT_FLOAT:
> +         if (*abi_float != ABI_SOFT_FLOAT) goto error_float_abi;
> +         break;
> +
> +       case ISA_SINGLE_FLOAT:
> +         if (*abi_float != ABI_SINGLE_FLOAT) goto error_float_abi;
> +         break;
> +
> +       case ISA_DOUBLE_FLOAT:
> +         if (*abi_float != ABI_DOUBLE_FLOAT) goto error_float_abi;
> +         break;
> 

The goto statements should be in a new line (coding style).

> --- /dev/null
> +++ b/gcc/config/loongarch/gnu-user.h
/* snip */

> +#define GLIBC_DYNAMIC_LINKER_LP64 "/lib64/ld.so.1"

It is "ld-linux-loongarch-lp64d.so.x" in the latest ELF psABI.  "x" is
now 0 but we have an ongoing discussion to make it 1.

> +++ b/gcc/config/loongarch/sync.md
/* snip */

> +(define_insn "atomic_cas_value_strong<mode>"
> +  [(set (match_operand:GPR 0 "register_operand" "=&r")
> +       (match_operand:GPR 1 "memory_operand" "+ZC"))
> +   (set (match_dup 1)
> +       (unspec_volatile:GPR [(match_operand:GPR 2 "reg_or_0_operand" "rJ")
> +                             (match_operand:GPR 3 "reg_or_0_operand" "rJ")
> +                             (match_operand:SI 4 "const_int_operand")  ;; mod_s
> +                             (match_operand:SI 5 "const_int_operand")] ;; mod_f
> +        UNSPEC_COMPARE_AND_SWAP))
> +   (clobber (match_scratch:GPR 6 "=&r"))]
> +  ""
> +{
> +  static char buff[256] = {0};

> +  buff[0] = '\0';
> +  sprintf (buff + strlen (buff), "%%G5\\n\\t");
> +  sprintf (buff + strlen (buff), "1:\\n\\t");
> +  sprintf (buff + strlen (buff), "ll.<amo>\\t%%0,%%1\\n\\t");
> +  sprintf (buff + strlen (buff), "bne\\t%%0,%%z2,2f\\n\\t");
> +  sprintf (buff + strlen (buff), "or%%i3\\t%%6,$zero,%%3\\n\\t");
> +  sprintf (buff + strlen (buff), "sc.<amo>\\t%%6,%%1\\n\\t");
> +  sprintf (buff + strlen (buff), "beq\\t$zero,%%6,1b\\n\\t");
> +  sprintf (buff + strlen (buff), "b\\t3f\\n\\t");
> +  sprintf (buff + strlen (buff), "2:\\n\\t");
> +  sprintf (buff + strlen (buff), "dbar\\t0x700\\n\\t");
> +  sprintf (buff + strlen (buff), "3:\\n\\t");
> +
> +  return buff;
> +}

These "cascading" sprintf/strlen looks stupid. It can be simply:

  return "%G5\\n\\t"
         "1:\\n\\t"
         "ll.<amo>\\t%0,%1\\n\\t"
         ...
         "3:\\n\\t";

The compiler will concatenate the string literals so there will be no
runtime overhead.

And there should be some comment to explain this LL/SC loop and dbar
workaround IMO.

Likewise for other atomic LL/SC expansions.
  

You have:

> +#define GLIBC_DYNAMIC_LINKER_LP64 "/lib64/ld.so.1"

See my comments on the glibc patch series 
<https://sourceware.org/pipermail/libc-alpha/2021-August/130298.html>.  
Specifically, the point that all new glibc ports should have unique 
per-ABI dynamic linker names for each ABI supported by the port, 
preferably referencing the architecture name somewhere in the dynamic 
linker name.  /lib64/ld.so.1 is a name that's already in use, so should 
not be used by any ABI of this new port.

> +      error ("%<-march=%s%> does not work on a cross compiler.",

Error messages should not end with '.'.

> +      error ("%<-mtune=%s%> does not work on a cross compiler.",

Likewise.

I didn't see any additions to contrib/config-list.mk anywhere in the patch 
series.  (See "Back End" in sourcebuild.texi for a list of places you may 
need to update as part of a GCC port, including config-list.mk.)

Please make sure the back end builds cleanly with current GCC mainline.  
This can be tested either with a native bootstrap, or by building a cross 
compiler, using a native compiler of the same GCC mainline version for the 
build and configuring using --enable-werror-always (that configure option 
has the effect of enabling -Werror in the same way that later bootstrap 
stages in a native bootstrap do).
  

On Mon, 2021-11-08 at 23:14 +0000, Joseph Myers wrote:

/* snip */

> Please make sure the back end builds cleanly with current GCC mainline.  
> This can be tested either with a native bootstrap, or by building a cross 
> compiler, using a native compiler of the same GCC mainline version for the 
> build and configuring using --enable-werror-always (that configure option 
> has the effect of enabling -Werror in the same way that later bootstrap 
> stages in a native bootstrap do).

gcc trunk does not build with glibc-2.34+ and --enable-werror-always :(

gcc -c -g -O2 -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes 
-Wold-style-definition -Wmissing-format-attribute -Wno-overlength-strings -pedan
tic -Wno-long-long -Werror  -DHAVE_CONFIG_H -I. -I../../../fixincludes -I../incl
ude -I../../../fixincludes/../include ../../../fixincludes/fixincl.c
../../../fixincludes/fixincl.c: In function ‘process’:
../../../fixincludes/fixincl.c:1356:7: error: argument 1 is null but the corresp
onding size argument 2 value is 4096 [-Werror=nonnull]
 1356 |       fprintf (stderr, "Cannot access %s from %s\n\terror %d (%s)\n",
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1357 |                pz_curr_file, getcwd ((char *) NULL, MAXPATHLEN),
      |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1358 |                erno, xstrerror (erno));
      |                ~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../../../fixincludes/system.h:192,
                 from ../../../fixincludes/fixlib.h:29,
                 from ../../../fixincludes/fixincl.c:24:
/usr/include/unistd.h:531:14: note: in a call to function ‘getcwd’ declared with attribute ‘access (write_only, 1, 2)’
  531 | extern char *getcwd (char *__buf, size_t __size) __THROW __wur
      |              ^~~~~~
cc1: all warnings being treated as errors

I've sent the fix as
https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583820.html.
  

On Tue, 2021-11-09 at 21:53 +0800, Xi Ruoyao via Gcc-patches wrote:
> On Mon, 2021-11-08 at 23:14 +0000, Joseph Myers wrote:
> 
> /* snip */
> 
> > Please make sure the back end builds cleanly with current GCC mainline.  
> > This can be tested either with a native bootstrap, or by building a cross 
> > compiler, using a native compiler of the same GCC mainline version for the 
> > build and configuring using --enable-werror-always (that configure option 
> > has the effect of enabling -Werror in the same way that later bootstrap 
> > stages in a native bootstrap do).
> 
> gcc trunk does not build with glibc-2.34+ and --enable-werror-always :(
> 
> I've sent the fix as
> https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583820.html.

I applied the 7 patches and my fix onto c71cb26a9e. A native bootstrap
with --enable-werror-always has succeeded.
  

On Tue, 2021-11-09 at 23:52 +0800, Xi Ruoyao via Gcc-patches wrote:

> > gcc trunk does not build with glibc-2.34+ and --enable-werror-always
> > :(
> > 
> > I've sent the fix as
> > https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583820.html.
> 
> I applied the 7 patches and my fix onto c71cb26a9e. A native bootstrap
> with --enable-werror-always has succeeded.

A test summary is attached.