LoongArch Port: libgcc

2022-03-29  Chenghua Xu  <xuchenghua@loongson.cn>
	    Lulu Cheng  <chenglulu@loongson.cn>

libgcc/ChangeLog:

	* config/loongarch/crtfastmath.c: New file.
	* config/loongarch/linux-unwind.h: Like wise.
	* config/loongarch/sfp-machine.h: Like wise.
	* config/loongarch/t-crtstuff: Like wise.
	* config/loongarch/t-loongarch: Like wise.
	* config/loongarch/t-loongarch64: Like wise.
	* config/loongarch/t-softfp-tf: Like wise.
	* config.host: Add LoongArch tuples.
	* configure.ac: Add LoongArch support.

9 files changed, 328 insertions, 2 deletions

diff --git a/libgcc/config.host b/libgcc/config.host
index 094fd3ad254..8c56fcae5d2 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -138,6 +138,22 @@ hppa*-*-*)
 lm32*-*-*)
 	cpu_type=lm32
 	;;
+loongarch*-*-*)
+	cpu_type=loongarch
+	tmake_file="loongarch/t-loongarch"
+	if test "${libgcc_cv_loongarch_hard_float}" = yes; then
+		tmake_file="${tmake_file} t-hardfp-sfdf t-hardfp"
+	else
+		tmake_file="${tmake_file} t-softfp-sfdf"
+	fi
+	if test "${ac_cv_sizeof_long_double}" = 16; then
+		tmake_file="${tmake_file} loongarch/t-softfp-tf"
+	fi
+	if test "${host_address}" = 64; then
+		tmake_file="${tmake_file} loongarch/t-loongarch64"
+	fi
+	tmake_file="${tmake_file} t-softfp"
+	;;
 m32r*-*-*)
         cpu_type=m32r
         ;;
@@ -925,7 +941,17 @@ lm32-*-rtems*)
 lm32-*-uclinux*)
         extra_parts="$extra_parts crtbegin.o crtendS.o crtbeginT.o"
         tmake_file="lm32/t-lm32 lm32/t-uclinux t-libgcc-pic t-softfp-sfdf t-softfp"
-	;;	
+	;;
+loongarch*-*-linux*)
+	extra_parts="$extra_parts crtfastmath.o"
+	tmake_file="${tmake_file} t-crtfm loongarch/t-crtstuff"
+	case ${host} in
+	  *)
+	    tmake_file="${tmake_file} t-slibgcc-libgcc"
+	    ;;
+	esac
+	md_unwind_header=loongarch/linux-unwind.h
+	;;
 m32r-*-elf*)
 	tmake_file="$tmake_file m32r/t-m32r t-fdpbit"
 	extra_parts="$extra_parts crtinit.o crtfini.o"
diff --git a/libgcc/config/loongarch/crtfastmath.c b/libgcc/config/loongarch/crtfastmath.c
new file mode 100644
index 00000000000..52b0d6da087
--- /dev/null
+++ b/libgcc/config/loongarch/crtfastmath.c
@@ -0,0 +1,52 @@
+/* Copyright (C) 2021-2022 Free Software Foundation, Inc.
+   Contributed by Loongson Ltd.
+   Based on MIPS target for GNU compiler.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License
+and a copy of the GCC Runtime Library Exception along with this
+program; see the files COPYING3 and COPYING.RUNTIME respectively.
+If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef __loongarch_hard_float
+
+/* Rounding control.  */
+#define _FPU_RC_NEAREST 0x000     /* RECOMMENDED.  */
+#define _FPU_RC_ZERO    0x100
+#define _FPU_RC_UP      0x200
+#define _FPU_RC_DOWN    0x300
+
+/* Enable interrupts for IEEE exceptions.  */
+#define _FPU_IEEE     0x0000001F
+
+/* Macros for accessing the hardware control word.  */
+#define _FPU_GETCW(cw) __asm__ volatile ("movfcsr2gr %0,$r0" : "=r" (cw))
+#define _FPU_SETCW(cw) __asm__ volatile ("movgr2fcsr $r0,%0" : : "r" (cw))
+
+static void __attribute__((constructor))
+set_fast_math (void)
+{
+  unsigned int fcr;
+
+  /* Flush to zero, round to nearest, IEEE exceptions disabled.  */
+  fcr = _FPU_RC_NEAREST;
+
+  _FPU_SETCW (fcr);
+}
+
+#endif /* __loongarch_hard_float  */
diff --git a/libgcc/config/loongarch/linux-unwind.h b/libgcc/config/loongarch/linux-unwind.h
new file mode 100644
index 00000000000..89c168c8272
--- /dev/null
+++ b/libgcc/config/loongarch/linux-unwind.h
@@ -0,0 +1,80 @@
+/* DWARF2 EH unwinding support for LoongArch Linux.
+   Copyright (C) 2021-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef inhibit_libc
+/* Do code reading to identify a signal frame, and set the frame
+   state data appropriately.  See unwind-dw2.c for the structs.  */
+
+#include <signal.h>
+#include <sys/syscall.h>
+#include <sys/ucontext.h>
+
+#define MD_FALLBACK_FRAME_STATE_FOR loongarch_fallback_frame_state
+
+static _Unwind_Reason_Code
+loongarch_fallback_frame_state (struct _Unwind_Context *context,
+				_Unwind_FrameState *fs)
+{
+  u_int32_t *pc = (u_int32_t *) context->ra;
+  struct sigcontext *sc;
+  _Unwind_Ptr new_cfa;
+  int i;
+
+  /* 03822c0b li.d a7, 0x8b (sigreturn)  */
+  /* 002b0000 syscall 0  */
+  if (pc[1] != 0x002b0000)
+    return _URC_END_OF_STACK;
+  if (pc[0] == 0x03822c0b)
+    {
+      struct rt_sigframe
+      {
+	siginfo_t info;
+	ucontext_t uc;
+      } *rt_ = context->cfa;
+      sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
+    }
+  else
+    return _URC_END_OF_STACK;
+
+  new_cfa = (_Unwind_Ptr) sc;
+  fs->regs.cfa_how = CFA_REG_OFFSET;
+  fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
+  fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
+
+  for (i = 0; i < 32; i++)
+    {
+      fs->regs.reg[i].how = REG_SAVED_OFFSET;
+      fs->regs.reg[i].loc.offset = (_Unwind_Ptr) & (sc->sc_regs[i]) - new_cfa;
+    }
+
+  fs->signal_frame = 1;
+  fs->regs.reg[__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__].how
+    = REG_SAVED_VAL_OFFSET;
+  fs->regs.reg[__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__].loc.offset
+    = (_Unwind_Ptr) (sc->sc_pc) - new_cfa;
+  fs->retaddr_column = __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__;
+
+  return _URC_NO_REASON;
+}
+#endif
diff --git a/libgcc/config/loongarch/sfp-machine.h b/libgcc/config/loongarch/sfp-machine.h
new file mode 100644
index 00000000000..c81be71815e
--- /dev/null
+++ b/libgcc/config/loongarch/sfp-machine.h
@@ -0,0 +1,152 @@
+/* softfp machine description for LoongArch.
+   Copyright (C) 2021-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#ifdef __loongarch64
+#define _FP_W_TYPE_SIZE 64
+#define _FP_W_TYPE unsigned long long
+#define _FP_WS_TYPE signed long long
+#define _FP_I_TYPE long long
+
+typedef int TItype __attribute__ ((mode (TI)));
+typedef unsigned int UTItype __attribute__ ((mode (TI)));
+#define TI_BITS (__CHAR_BIT__ * (int) sizeof (TItype))
+
+#define _FP_MUL_MEAT_S(R, X, Y) \
+  _FP_MUL_MEAT_1_wide (_FP_WFRACBITS_S, R, X, Y, umul_ppmm)
+#define _FP_MUL_MEAT_D(R, X, Y) \
+  _FP_MUL_MEAT_1_wide (_FP_WFRACBITS_D, R, X, Y, umul_ppmm)
+#define _FP_MUL_MEAT_Q(R, X, Y) \
+  _FP_MUL_MEAT_2_wide (_FP_WFRACBITS_Q, R, X, Y, umul_ppmm)
+
+#define _FP_DIV_MEAT_S(R, X, Y) _FP_DIV_MEAT_1_udiv_norm (S, R, X, Y)
+#define _FP_DIV_MEAT_D(R, X, Y) _FP_DIV_MEAT_1_udiv_norm (D, R, X, Y)
+#define _FP_DIV_MEAT_Q(R, X, Y) _FP_DIV_MEAT_2_udiv (Q, R, X, Y)
+
+#define _FP_NANFRAC_S ((_FP_QNANBIT_S << 1) - 1)
+#define _FP_NANFRAC_D ((_FP_QNANBIT_D << 1) - 1)
+#define _FP_NANFRAC_Q ((_FP_QNANBIT_Q << 1) - 1), -1
+#else
+#define _FP_W_TYPE_SIZE 32
+#define _FP_W_TYPE unsigned int
+#define _FP_WS_TYPE signed int
+#define _FP_I_TYPE int
+
+#define _FP_MUL_MEAT_S(R, X, Y) \
+  _FP_MUL_MEAT_1_wide (_FP_WFRACBITS_S, R, X, Y, umul_ppmm)
+#define _FP_MUL_MEAT_D(R, X, Y) \
+  _FP_MUL_MEAT_2_wide (_FP_WFRACBITS_D, R, X, Y, umul_ppmm)
+#define _FP_MUL_MEAT_Q(R, X, Y) \
+  _FP_MUL_MEAT_4_wide (_FP_WFRACBITS_Q, R, X, Y, umul_ppmm)
+
+#define _FP_DIV_MEAT_S(R, X, Y) _FP_DIV_MEAT_1_udiv_norm (S, R, X, Y)
+#define _FP_DIV_MEAT_D(R, X, Y) _FP_DIV_MEAT_2_udiv (D, R, X, Y)
+#define _FP_DIV_MEAT_Q(R, X, Y) _FP_DIV_MEAT_4_udiv (Q, R, X, Y)
+
+#define _FP_NANFRAC_S ((_FP_QNANBIT_S << 1) - 1)
+#define _FP_NANFRAC_D ((_FP_QNANBIT_D << 1) - 1), -1
+#define _FP_NANFRAC_Q ((_FP_QNANBIT_Q << 1) - 1), -1, -1, -1
+#endif
+
+/* The type of the result of a floating point comparison.  This must
+   match __libgcc_cmp_return__ in GCC for the target.  */
+typedef int __gcc_CMPtype __attribute__ ((mode (__libgcc_cmp_return__)));
+#define CMPtype __gcc_CMPtype
+
+#define _FP_NANSIGN_S 0
+#define _FP_NANSIGN_D 0
+#define _FP_NANSIGN_Q 0
+
+#define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
+
+/* NaN payloads should be preserved for NAN2008.  */
+#define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \
+  do \
+    { \
+      R##_s = X##_s; \
+      _FP_FRAC_COPY_##wc (R, X); \
+      R##_c = FP_CLS_NAN; \
+    } \
+  while (0)
+
+#ifdef __loongarch_hard_float
+#define FP_EX_INVALID 0x100000
+#define FP_EX_DIVZERO 0x080000
+#define FP_EX_OVERFLOW 0x040000
+#define FP_EX_UNDERFLOW 0x020000
+#define FP_EX_INEXACT 0x010000
+#define FP_EX_ALL \
+  (FP_EX_INVALID | FP_EX_DIVZERO | FP_EX_OVERFLOW | FP_EX_UNDERFLOW \
+   | FP_EX_INEXACT)
+
+#define FP_EX_ENABLE_SHIFT 16
+#define FP_EX_CAUSE_SHIFT 8
+
+#define FP_RND_NEAREST 0x000
+#define FP_RND_ZERO 0x100
+#define FP_RND_PINF 0x200
+#define FP_RND_MINF 0x300
+#define FP_RND_MASK 0x300
+
+#define _FP_DECL_EX \
+  unsigned long int _fcsr __attribute__ ((unused)) = FP_RND_NEAREST
+
+#define FP_INIT_ROUNDMODE \
+  do \
+    { \
+      _fcsr = __builtin_loongarch_movfcsr2gr (0); \
+    } \
+  while (0)
+
+#define FP_ROUNDMODE (_fcsr & FP_RND_MASK)
+
+#define FP_TRAPPING_EXCEPTIONS ((_fcsr << FP_EX_ENABLE_SHIFT) & FP_EX_ALL)
+
+#define FP_HANDLE_EXCEPTIONS \
+  do \
+    { \
+      _fcsr &= ~(FP_EX_ALL << FP_EX_CAUSE_SHIFT); \
+      _fcsr |= _fex | (_fex << FP_EX_CAUSE_SHIFT); \
+      __builtin_loongarch_movgr2fcsr (0, _fcsr); \
+    } \
+  while (0)
+
+#else
+#define FP_EX_INVALID (1 << 4)
+#define FP_EX_DIVZERO (1 << 3)
+#define FP_EX_OVERFLOW (1 << 2)
+#define FP_EX_UNDERFLOW (1 << 1)
+#define FP_EX_INEXACT (1 << 0)
+#endif
+
+#define _FP_TININESS_AFTER_ROUNDING 1
+
+#define __LITTLE_ENDIAN 1234
+
+#define __BYTE_ORDER __LITTLE_ENDIAN
+
+/* Define ALIASNAME as a strong alias for NAME.  */
+#define strong_alias(name, aliasname) _strong_alias (name, aliasname)
+#define _strong_alias(name, aliasname) \
+  extern __typeof (name) aliasname __attribute__ ((alias (#name)));
diff --git a/libgcc/config/loongarch/t-crtstuff b/libgcc/config/loongarch/t-crtstuff
new file mode 100644
index 00000000000..b8c36eb66b7
--- /dev/null
+++ b/libgcc/config/loongarch/t-crtstuff
@@ -0,0 +1,5 @@
+# -fasynchronous-unwind-tables is on by default for LoongArch.
+# We turn it off for crt*.o because it would make __EH_FRAME_BEGIN__ point
+# to .eh_frame data from crtbeginT.o instead of the user-defined object
+# during static linking.
+CRTSTUFF_T_CFLAGS += -fno-omit-frame-pointer -fno-asynchronous-unwind-tables
diff --git a/libgcc/config/loongarch/t-loongarch b/libgcc/config/loongarch/t-loongarch
new file mode 100644
index 00000000000..2a7dbf6ca83
--- /dev/null
+++ b/libgcc/config/loongarch/t-loongarch
@@ -0,0 +1,7 @@
+LIB2_SIDITI_CONV_FUNCS = yes
+
+softfp_float_modes :=
+softfp_int_modes := si di
+softfp_extensions :=
+softfp_truncations :=
+softfp_exclude_libgcc2 := n
diff --git a/libgcc/config/loongarch/t-loongarch64 b/libgcc/config/loongarch/t-loongarch64
new file mode 100644
index 00000000000..a1e3513e288
--- /dev/null
+++ b/libgcc/config/loongarch/t-loongarch64
@@ -0,0 +1 @@
+softfp_int_modes += ti
diff --git a/libgcc/config/loongarch/t-softfp-tf b/libgcc/config/loongarch/t-softfp-tf
new file mode 100644
index 00000000000..306677b1255
--- /dev/null
+++ b/libgcc/config/loongarch/t-softfp-tf
@@ -0,0 +1,3 @@
+softfp_float_modes += tf
+softfp_extensions += sftf dftf
+softfp_truncations += tfsf tfdf
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 6f0b67c2adc..2fc9d5d7c93 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -324,7 +324,7 @@ AC_CACHE_CHECK([whether assembler supports CFI directives], [libgcc_cv_cfi],
 # word size rather than the address size.
 cat > conftest.c <<EOF
 #if defined(__x86_64__) || (!defined(__i386__) && defined(__LP64__)) \
-    || defined(__mips64)
+    || defined(__mips64) || defined(__loongarch64)
 host_address=64
 #else
 host_address=32