LoongArch: Libitm add LoongArch support.

diff --git a/libitm/config/loongarch/asm.h b/libitm/config/loongarch/asm.h
new file mode 100644
index 00000000000..a8e3304bb19
--- /dev/null
+++ b/libitm/config/loongarch/asm.h
@@ -0,0 +1,54 @@ 
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Loongson Co. Ltd.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm 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 of the License, or
+   (at your option) any later version.
+
+   Libitm 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 _LA_ASM_H
+#define _LA_ASM_H
+
+#if defined(__loongarch_lp64)
+#  define GPR_L ld.d
+#  define GPR_S st.d
+#  define SZ_GPR 8
+#  define ADDSP(si)   addi.d  $sp, $sp, si
+#elif defined(__loongarch64_ilp32)
+#  define GPR_L ld.w
+#  define GPR_S st.w
+#  define SZ_GPR 4
+#  define ADDSP(si)   addi.w  $sp, $sp, si
+#else
+#  error Unsupported GPR size (must be 64-bit or 32-bit).
+#endif
+
+#if defined(__loongarch_double_float)
+#  define FPR_L fld.d
+#  define FPR_S fst.d
+#  define SZ_FPR 8
+#elif defined(__loongarch_single_float)
+#  define FPR_L fld.s
+#  define FPR_S fst.s
+#  define SZ_FPR 4
+#else
+#  define SZ_FPR 0
+#endif
+
+#endif  /* _LA_ASM_H */
diff --git a/libitm/config/loongarch/sjlj.S b/libitm/config/loongarch/sjlj.S
new file mode 100644
index 00000000000..a5f9fadde34
--- /dev/null
+++ b/libitm/config/loongarch/sjlj.S
@@ -0,0 +1,127 @@ 
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Loongson Co. Ltd.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm 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 of the License, or
+   (at your option) any later version.
+
+   Libitm 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/>.  */
+
+#include "asmcfi.h"
+#include "asm.h"
+
+	.text
+	.align	2
+	.global	_ITM_beginTransaction
+	.type	_ITM_beginTransaction, @function
+
+_ITM_beginTransaction:
+        cfi_startproc
+        move   $r5, $sp
+        ADDSP(-(12*SZ_GPR+8*SZ_FPR))
+        cfi_adjust_cfa_offset(12*SZ_GPR+8*SZ_FPR)
+
+        /* Frame Pointer */
+        GPR_S  $fp, $sp, 0*SZ_GPR
+        cfi_rel_offset(22, 0)
+
+        /* Return Address */
+        GPR_S  $r1, $sp, 1*SZ_GPR
+        cfi_rel_offset(1, SZ_GPR)
+
+        /* Caller's $sp */
+        GPR_S  $r5, $sp, 2*SZ_GPR
+
+        /* Callee-saved scratch GPRs (r23-r31) */
+        GPR_S  $s0, $sp, 3*SZ_GPR
+        GPR_S  $s1, $sp, 4*SZ_GPR
+        GPR_S  $s2, $sp, 5*SZ_GPR
+        GPR_S  $s3, $sp, 6*SZ_GPR
+        GPR_S  $s4, $sp, 7*SZ_GPR
+        GPR_S  $s5, $sp, 8*SZ_GPR
+        GPR_S  $s6, $sp, 9*SZ_GPR
+        GPR_S  $s7, $sp, 10*SZ_GPR
+        GPR_S  $s8, $sp, 11*SZ_GPR
+
+#if !defined(__loongarch_soft_float)
+        /* Callee-saved scratch FPRs (f24-f31) */
+        FPR_S  $f24, $sp, 12*SZ_GPR + 0*SZ_FPR
+        FPR_S  $f25, $sp, 12*SZ_GPR + 1*SZ_FPR
+        FPR_S  $f26, $sp, 12*SZ_GPR + 2*SZ_FPR
+        FPR_S  $f27, $sp, 12*SZ_GPR + 3*SZ_FPR
+        FPR_S  $f28, $sp, 12*SZ_GPR + 4*SZ_FPR
+        FPR_S  $f29, $sp, 12*SZ_GPR + 5*SZ_FPR
+        FPR_S  $f30, $sp, 12*SZ_GPR + 6*SZ_FPR
+        FPR_S  $f31, $sp, 12*SZ_GPR + 7*SZ_FPR
+#endif
+        move   $fp, $sp
+
+        /* Invoke GTM_begin_transaction with the struct we've just built.  */
+        move   $r5, $sp
+        bl     %plt(GTM_begin_transaction)
+
+        /* Return. (no call-saved scratch reg needs to be restored here)  */
+        GPR_L  $fp, $sp, 0*SZ_GPR
+        cfi_restore(22)
+        GPR_L  $r1, $sp, 1*SZ_GPR
+        cfi_restore(1)
+
+        ADDSP(12*SZ_GPR+8*SZ_FPR)
+        cfi_adjust_cfa_offset(-(12*SZ_GPR+8*SZ_FPR))
+
+        jr     $r1
+        cfi_endproc
+	.size	_ITM_beginTransaction, . - _ITM_beginTransaction
+
+	.align	2
+	.global	GTM_longjmp
+	.hidden	GTM_longjmp
+	.type	GTM_longjmp, @function
+
+GTM_longjmp:
+        cfi_startproc
+        GPR_L  $s0, $r5, 3*SZ_GPR
+        GPR_L  $s1, $r5, 4*SZ_GPR
+        GPR_L  $s2, $r5, 5*SZ_GPR
+        GPR_L  $s3, $r5, 6*SZ_GPR
+        GPR_L  $s4, $r5, 7*SZ_GPR
+        GPR_L  $s5, $r5, 8*SZ_GPR
+        GPR_L  $s6, $r5, 9*SZ_GPR
+        GPR_L  $s7, $r5, 10*SZ_GPR
+        GPR_L  $s8, $r5, 11*SZ_GPR
+
+        FPR_L  $f24, $r5, 12*SZ_GPR + 0*SZ_FPR
+        FPR_L  $f25, $r5, 12*SZ_GPR + 1*SZ_FPR
+        FPR_L  $f26, $r5, 12*SZ_GPR + 2*SZ_FPR
+        FPR_L  $f27, $r5, 12*SZ_GPR + 3*SZ_FPR
+        FPR_L  $f28, $r5, 12*SZ_GPR + 4*SZ_FPR
+        FPR_L  $f29, $r5, 12*SZ_GPR + 5*SZ_FPR
+        FPR_L  $f30, $r5, 12*SZ_GPR + 6*SZ_FPR
+        FPR_L  $f31, $r5, 12*SZ_GPR + 7*SZ_FPR
+
+        GPR_L  $r7, $r5, 2*SZ_GPR
+        GPR_L  $fp, $r5, 0*SZ_GPR
+        GPR_L  $r1, $r5, 1*SZ_GPR
+        cfi_def_cfa(5, 0)
+        move   $sp, $r7
+        jr     $r1
+        cfi_endproc
+	.size	GTM_longjmp, . - GTM_longjmp
+
+#ifdef __linux__
+.section .note.GNU-stack, "", @progbits
+#endif
diff --git a/libitm/config/loongarch/target.h b/libitm/config/loongarch/target.h
new file mode 100644
index 00000000000..0c5cf3ada57
--- /dev/null
+++ b/libitm/config/loongarch/target.h
@@ -0,0 +1,50 @@ 
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Loongson Co. Ltd.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm 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 of the License, or
+   (at your option) any later version.
+
+   Libitm 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/>.  */
+
+namespace GTM HIDDEN {
+
+typedef struct gtm_jmpbuf
+  {
+    long int fp;        /* Frame Pointer: r22 */
+    long int pc;        /* Return Address: r1 */
+    void *cfa;          /* CFA: r3 */
+    long int gpr[9];	/* Callee-saved scratch GPRs: r23(s0)-r31(s8) */
+
+    /* Callee-saved scratch FPRs: f24-f31 */
+#if defined(__loongarch_double_float)
+    double fpr[8];
+#elif defined(__loongarch_single_float)
+    float fpr[8];
+#endif
+  } gtm_jmpbuf;
+
+#define HW_CACHELINE_SIZE 128
+
+static inline void
+cpu_relax (void)
+{
+    __asm__ volatile ("" : : : "memory");
+}
+
+} // namespace GTM
diff --git a/libitm/configure.tgt b/libitm/configure.tgt
index 06e90973ef3..4c0e78cff42 100644
--- a/libitm/configure.tgt
+++ b/libitm/configure.tgt
@@ -80,6 +80,8 @@  EOF
 	ARCH=x86
 	;;
 
+  loongarch*)   ARCH=loongarch ;;
+
   sh*)		ARCH=sh ;;
 
   sparc)