nsz Git - libfirm/blob - ir/be/arm/arm_cconv.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief   calling convention helpers
  23  * @author  Matthias Braun
  24  */
  25 #include "config.h"
  26
  27 #include "arm_cconv.h"
  28 #include "beirg.h"
  29 #include "irmode.h"
  30 #include "typerep.h"
  31 #include "xmalloc.h"
  32 #include "error.h"
  33 #include "util.h"
  34
  35 static const unsigned ignore_regs[] = {
  36         REG_R12,
  37         REG_SP,
  38         REG_PC,
  39         REG_FL,
  40 };
  41
  42 static const arch_register_t* const param_regs[] = {
  43         &arm_registers[REG_R0],
  44         &arm_registers[REG_R1],
  45         &arm_registers[REG_R2],
  46         &arm_registers[REG_R3]
  47 };
  48
  49 static const arch_register_t* const result_regs[] = {
  50         &arm_registers[REG_R0],
  51         &arm_registers[REG_R1],
  52         &arm_registers[REG_R2],
  53         &arm_registers[REG_R3]
  54 };
  55
  56 static const arch_register_t* const float_result_regs[] = {
  57         &arm_registers[REG_F0],
  58         &arm_registers[REG_F1]
  59 };
  60
  61 calling_convention_t *arm_decide_calling_convention(const ir_graph *irg,
  62                                                     ir_type *function_type)
  63 {
  64         unsigned              stack_offset      = 0;
  65         unsigned              n_param_regs_used = 0;
  66         reg_or_stackslot_t   *params;
  67         reg_or_stackslot_t   *results;
  68         size_t const          n_param_regs        = ARRAY_SIZE(param_regs);
  69         size_t const          n_result_regs       = ARRAY_SIZE(result_regs);
  70         size_t const          n_float_result_regs = ARRAY_SIZE(float_result_regs);
  71         size_t                n_params;
  72         size_t                n_results;
  73         size_t                i;
  74         size_t                regnum;
  75         size_t                float_regnum;
  76         calling_convention_t *cconv;
  77
  78         /* determine how parameters are passed */
  79         n_params = get_method_n_params(function_type);
  80         regnum   = 0;
  81         params   = XMALLOCNZ(reg_or_stackslot_t, n_params);
  82
  83         for (i = 0; i < n_params; ++i) {
  84                 ir_type            *param_type = get_method_param_type(function_type,i);
  85                 ir_mode            *mode       = get_type_mode(param_type);
  86                 int                 bits       = get_mode_size_bits(mode);
  87                 reg_or_stackslot_t *param      = &params[i];
  88                 param->type = param_type;
  89
  90                 if (regnum < n_param_regs) {
  91                         const arch_register_t *reg = param_regs[regnum++];
  92                         param->reg0 = reg;
  93                 } else {
  94                         param->offset = stack_offset;
  95                         /* increase offset 4 bytes so everything is aligned */
  96                         stack_offset += bits > 32 ? bits/8 : 4;
  97                         continue;
  98                 }
  99
 100                 /* we might need a 2nd 32bit component (for 64bit or double values) */
 101                 if (bits > 32) {
 102                         if (bits > 64)
 103                                 panic("only 32 and 64bit modes supported");
 104
 105                         if (regnum < n_param_regs) {
 106                                 const arch_register_t *reg = param_regs[regnum++];
 107                                 param->reg1 = reg;
 108                         } else {
 109                                 ir_mode *pmode = param_regs[0]->reg_class->mode;
 110                                 ir_type *type  = get_type_for_mode(pmode);
 111                                 param->type    = type;
 112                                 param->offset  = stack_offset;
 113                                 assert(get_mode_size_bits(pmode) == 32);
 114                                 stack_offset += 4;
 115                         }
 116                 }
 117         }
 118         n_param_regs_used = regnum;
 119
 120         n_results    = get_method_n_ress(function_type);
 121         regnum       = 0;
 122         float_regnum = 0;
 123         results      = XMALLOCNZ(reg_or_stackslot_t, n_results);
 124         for (i = 0; i < n_results; ++i) {
 125                 ir_type            *result_type = get_method_res_type(function_type, i);
 126                 ir_mode            *result_mode = get_type_mode(result_type);
 127                 reg_or_stackslot_t *result      = &results[i];
 128
 129                 if (mode_is_float(result_mode)) {
 130                         if (float_regnum >= n_float_result_regs) {
 131                                 panic("Too many float results");
 132                         } else {
 133                                 const arch_register_t *reg = float_result_regs[float_regnum++];
 134                                 result->reg0 = reg;
 135                         }
 136                 } else {
 137                         if (get_mode_size_bits(result_mode) > 32) {
 138                                 panic("Results with more than 32bits not supported yet");
 139                         }
 140
 141                         if (regnum >= n_result_regs) {
 142                                 panic("Too many results");
 143                         } else {
 144                                 const arch_register_t *reg = result_regs[regnum++];
 145                                 result->reg0 = reg;
 146                         }
 147                 }
 148         }
 149
 150         cconv                   = XMALLOCZ(calling_convention_t);
 151         cconv->parameters       = params;
 152         cconv->param_stack_size = stack_offset;
 153         cconv->n_reg_params     = n_param_regs_used;
 154         cconv->results          = results;
 155
 156         /* setup allocatable registers */
 157         if (irg != NULL) {
 158                 be_irg_t       *birg      = be_birg_from_irg(irg);
 159                 size_t          n_ignores = ARRAY_SIZE(ignore_regs);
 160                 struct obstack *obst      = &birg->obst;
 161                 size_t          r;
 162
 163                 assert(birg->allocatable_regs == NULL);
 164                 birg->allocatable_regs = rbitset_obstack_alloc(obst, N_ARM_REGISTERS);
 165                 rbitset_set_all(birg->allocatable_regs, N_ARM_REGISTERS);
 166                 for (r = 0; r < n_ignores; ++r) {
 167                         rbitset_clear(birg->allocatable_regs, ignore_regs[r]);
 168                 }
 169         }
 170
 171         return cconv;
 172 }
 173
 174 void arm_free_calling_convention(calling_convention_t *cconv)
 175 {
 176         free(cconv->parameters);
 177         free(cconv->results);
 178         free(cconv);
 179 }