[PATCH 11/21] Add calling function support

[juzhe.zhong@rivai.ai]

From: zhongjuzhe <juzhe.zhong@rivai.ai>

gcc/ChangeLog:

        * config/riscv/riscv.cc (struct riscv_arg_info): Add calling convention support.
        (riscv_get_arg_info): Add calling convention support.
        (riscv_function_arg_advance): Add calling convention support.
        (riscv_pass_by_reference): Add calling convention support.
        * config/riscv/riscv.h (GCC_RISCV_H): include <stdbool.h>.
        (V_RETURN): New macro define.
        (MAX_ARGS_IN_VECTOR_REGISTERS): New macro define.
        (MAX_ARGS_IN_MASK_REGISTERS): New macro define.
        (V_ARG_FIRST): New macro define.
        (V_ARG_LAST): New macro define.

gcc/testsuite/ChangeLog:

        * gcc.target/riscv/rvv/custom/calling_convention_1.c: New test.
        * gcc.target/riscv/rvv/custom/rvv-custom.exp: New test.
        
---
 gcc/config/riscv/riscv.cc                     | 90 +++++++++++++++++++
 gcc/config/riscv/riscv.h                      | 14 +++
 .../riscv/rvv/custom/calling_convention_1.c   | 46 ++++++++++
 .../riscv/rvv/custom/rvv-custom.exp           | 47 ++++++++++
 4 files changed, 197 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/custom/calling_convention_1.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/custom/rvv-custom.exp

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index e88057e992a..832c1754002 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -181,6 +181,18 @@ struct riscv_arg_info {
 
   /* The offset of the first register used, provided num_fprs is nonzero.  */
   unsigned int fpr_offset;
+
+  /* The number of vector registers allocated to this argument.  */
+  unsigned int num_vrs;
+
+  /* The offset of the first register used, provided num_vrs is nonzero.  */
+  unsigned int vr_offset;
+
+  /* The number of mask registers allocated to this argument.  */
+  unsigned int num_mrs;
+
+  /* The offset of the first register used, provided num_mrs is nonzero.  */
+  unsigned int mr_offset;
 };
 
 /* Information about an address described by riscv_address_type.
@@ -3225,11 +3237,13 @@ riscv_get_arg_info (struct riscv_arg_info *info, const CUMULATIVE_ARGS *cum,
   unsigned num_bytes, num_words;
   unsigned fpr_base = return_p ? FP_RETURN : FP_ARG_FIRST;
   unsigned gpr_base = return_p ? GP_RETURN : GP_ARG_FIRST;
+	unsigned vr_base = return_p ? V_RETURN : V_ARG_FIRST;
   unsigned alignment = riscv_function_arg_boundary (mode, type);
 
   memset (info, 0, sizeof (*info));
   info->gpr_offset = cum->num_gprs;
   info->fpr_offset = cum->num_fprs;
+	info->mr_offset = cum->num_mrs;
 
   if (named)
     {
@@ -3292,6 +3306,67 @@ riscv_get_arg_info (struct riscv_arg_info *info, const CUMULATIVE_ARGS *cum,
 				      gregno, TYPE_MODE (fields[1].type),
 				      fields[1].offset);
 	}
+      /*  Pass vectors in VRs. For the argument contain scalable vectors,
+          for example: foo (vint8m1_t a), we pass this in VRs to reduce
+          redundant register spills. The maximum vector arg registers is
+          MAX_ARGS_IN_VECTOR_REGISTERS. */
+      if (rvv_mode_p (mode))
+	{
+	  /*  For return vector register, we use V_RETURN as default. */
+	  if (return_p)
+	    {
+	      if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL)
+	        return gen_rtx_REG (mode, V_REG_FIRST);
+	      else
+	        return gen_rtx_REG (mode, vr_base);
+	    }
+	  /* The first mask register in argument we use is v0, the res of them
+	     we use v8,v9,.....etc same as vector registers.  */
+	  if (GET_MODE_CLASS (mode) == MODE_VECTOR_BOOL)
+	    {
+	      info->num_mrs = 1;
+	
+	      if (info->mr_offset + info->num_mrs <= MAX_ARGS_IN_MASK_REGISTERS)
+	        return gen_rtx_REG (mode, V_REG_FIRST);
+	    }
+	  /*  The number of vectors to pass in the function arg.
+	      When the mode size is less than a full vector, we
+	      use 1 vector to pass. */
+	  int nvecs;
+	  nvecs = known_le (GET_MODE_SIZE (mode), BYTES_PER_RISCV_VECTOR) ? 1 :
+	      exact_div (GET_MODE_SIZE (mode), BYTES_PER_RISCV_VECTOR).to_constant ();
+	  int align = rvv_regsize (mode);
+	  for (int i = 0; i + nvecs <= MAX_ARGS_IN_VECTOR_REGISTERS; i += 1)
+	    {
+	      if (!cum->used_vrs[i] && (i + 8) % align == 0)
+	        {
+	          bool find_space = true;
+	          int j = 1;
+	          for (; j < nvecs; j += 1)
+	            {
+	              if (cum->used_vrs[i + j])
+	                {
+	                  find_space = false;
+	                  break;
+	                }
+	            }
+	          if (find_space)
+	            {
+	              info->num_vrs = nvecs;
+	              info->vr_offset = i;
+	              return gen_rtx_REG(mode, vr_base + i);
+	            }
+	          else
+	            {
+	              /* skip the j num registers which can not be used */
+	              i += j;
+	            }
+	        }
+	    }
+	  info->num_vrs = 0;
+	  info->num_mrs = 0;
+	  return NULL_RTX;
+	}
     }
 
   /* Work out the size of the argument.  */
@@ -3344,6 +3419,15 @@ riscv_function_arg_advance (cumulative_args_t cum_v,
      argument on the stack.  */
   cum->num_fprs = info.fpr_offset + info.num_fprs;
   cum->num_gprs = info.gpr_offset + info.num_gprs;
+	if (info.num_vrs > 0)
+    {
+      for (unsigned int i = 0; i < info.num_vrs; i += 1)
+        {
+          /* set current used vector registers */
+          cum->used_vrs[info.vr_offset + i] = true;
+        }
+    }
+	cum->num_mrs = info.mr_offset + info.num_mrs;
 }
 
 /* Implement TARGET_ARG_PARTIAL_BYTES.  */
@@ -3401,6 +3485,12 @@ riscv_pass_by_reference (cumulative_args_t cum_v, const function_arg_info &arg)
       /* Don't pass by reference if we can use a floating-point register.  */
       riscv_get_arg_info (&info, cum, arg.mode, arg.type, arg.named, false);
       if (info.num_fprs)
+	return false;
+	    /* Don't pass by reference if we can use a RVV vector register.  */
+      if (info.num_vrs)
+	return false;
+	    /* Don't pass by reference if we can use a RVV mask register.  */
+      if (info.num_mrs)
 	return false;
     }
 
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index c54c984e70b..5de745bc824 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -22,6 +22,7 @@ along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_RISCV_H
 #define GCC_RISCV_H
 
+#include <stdbool.h>
 #include "config/riscv/riscv-opts.h"
 
 /* Target CPU builtins.  */
@@ -620,8 +621,13 @@ enum reg_class
 
 #define GP_RETURN GP_ARG_FIRST
 #define FP_RETURN (UNITS_PER_FP_ARG == 0 ? GP_RETURN : FP_ARG_FIRST)
+#define V_RETURN V_ARG_FIRST
 
 #define MAX_ARGS_IN_REGISTERS (riscv_abi == ABI_ILP32E ? 6 : 8)
+/*  Follow the calling convention in LLVM,
+    maximum 16 vector registers and 1 mask register in function arg.  */
+#define MAX_ARGS_IN_VECTOR_REGISTERS (16)
+#define MAX_ARGS_IN_MASK_REGISTERS (1)
 
 /* Symbolic macros for the first/last argument registers.  */
 
@@ -630,6 +636,8 @@ enum reg_class
 #define GP_TEMP_FIRST (GP_REG_FIRST + 5)
 #define FP_ARG_FIRST (FP_REG_FIRST + 10)
 #define FP_ARG_LAST  (FP_ARG_FIRST + MAX_ARGS_IN_REGISTERS - 1)
+#define V_ARG_FIRST (V_REG_FIRST + 8)
+#define V_ARG_LAST  (V_ARG_FIRST + MAX_ARGS_IN_VECTOR_REGISTERS - 1)
 
 #define CALLEE_SAVED_REG_NUMBER(REGNO)			\
   ((REGNO) >= 8 && (REGNO) <= 9 ? (REGNO) - 8 :		\
@@ -657,6 +665,12 @@ typedef struct {
 
   /* Number of floating-point registers used so far, likewise.  */
   unsigned int num_fprs;
+
+  /* The used state of args in vectors, 1 for used by prev arg, initial to 0 */
+  bool used_vrs[MAX_ARGS_IN_VECTOR_REGISTERS];
+
+  /* Number of mask registers used so far, up to MAX_ARGS_IN_MASK_REGISTERS. */
+  unsigned int num_mrs;
 } CUMULATIVE_ARGS;
 
 /* Initialize a variable CUM of type CUMULATIVE_ARGS
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/custom/calling_convention_1.c b/gcc/testsuite/gcc.target/riscv/rvv/custom/calling_convention_1.c
new file mode 100644
index 00000000000..5f79da2a9d6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/custom/calling_convention_1.c
@@ -0,0 +1,46 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+
+#include <stddef.h>
+#include <riscv_vector.h>
+
+void
+test (
+  vint8mf2_t a, vint8m4_t c, vint8m4_t d,vint8m2_t e, vint8m2_t b,  
+  vint8m1_t f,vint8m1_t f2, vint8m1_t f3, vint8m1_t f4,  vint8m2_t g,  vint8m2_t h,  
+  vbool16_t m1, vbool4_t m2, 
+  int8_t *a1, int8_t *b1, int8_t *c1,
+  size_t vl)
+{
+  /* f4 => a0, g => a1, h => a2, m2 => a3, 
+     a1 => a4, b1 => a5, c1 => a6, vl => a7
+
+     m1 => v0
+     a => v8, c => v12, d => v16, e => v10, 
+     b => v20, f => v9, f2 => v22, f3 => v23 */
+
+  vse8_v_i8mf2_m(m1, a1, a, vl);
+
+  vse8_v_i8m2_m(m2, b1, b, vl);
+
+  vse8_v_i8m4(c1, c, vl);
+  vse8_v_i8m4(c1, d, vl);
+
+  vse8_v_i8m2(c1, e, vl);
+
+  vse8_v_i8m1(c1, f, vl);
+  vse8_v_i8m1(c1, f2, vl);
+  vse8_v_i8m1(c1, f3, vl);
+  vse8_v_i8m1(c1, f4, vl);
+
+  vse8_v_i8m2(c1, g, vl);
+  vse8_v_i8m2(c1, h, vl);
+}
+/* { dg-final { scan-assembler-times {vse8.v\s+v8,\s*\(a4\),\s*v0.t} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v20,\s*\(a5\),\s*v0.t} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v12,\s*\(a6\)} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v16,\s*\(a6\)} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v10,\s*\(a6\)} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v9,\s*\(a6\)} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v22,\s*\(a6\)} 1 } } */
+/* { dg-final { scan-assembler-times {vse8.v\s+v23,\s*\(a6\)} 1 } } */
\ No newline at end of file
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/custom/rvv-custom.exp b/gcc/testsuite/gcc.target/riscv/rvv/custom/rvv-custom.exp
new file mode 100644
index 00000000000..4956ac0b184
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/custom/rvv-custom.exp
@@ -0,0 +1,47 @@
+# Copyright (C) 2022-2022 Free Software Foundation, Inc.
+
+# This program 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.
+#
+# This program 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.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# GCC testsuite that uses the `dg.exp' driver.
+
+# Exit immediately if this isn't a RISC-V target.
+if ![istarget riscv*-*-*] then {
+  return
+}
+
+# Load support procs.
+load_lib gcc-dg.exp
+
+# If a testcase doesn't have special options, use these.
+global DEFAULT_CFLAGS
+if ![info exists DEFAULT_CFLAGS] then {
+    set DEFAULT_CFLAGS "-pedantic-errors -ansi"
+}
+
+set gcc_march "rv64gcv_zfh"
+if [istarget riscv32-*-*] then {
+  set gcc_march "rv32gcv_zfh"
+}
+
+# Initialize `dg'.
+dg-init
+
+# Main loop.
+set CFLAGS "$DEFAULT_CFLAGS -march=$gcc_march -std=gnu11"
+dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.c]] \
+	"" $CFLAGS
+
+# All done.
+dg-finish
\ No newline at end of file
-- 
2.36.1