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  * @version $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "arm_cconv.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 /* determine how function parameters and return values are passed. */
  43 calling_convention_t *arm_decide_calling_convention(const ir_graph *irg,
  44                                                     ir_type *function_type)
  45 {
  46         int                   stack_offset = 0;
  47         reg_or_stackslot_t   *params;
  48         reg_or_stackslot_t   *results;
  49         int                   n_param_regs
  50                 = sizeof(param_regs)/sizeof(param_regs[0]);
  51         int                   n_result_regs
  52                 = sizeof(result_regs)/sizeof(result_regs[0]);
  53         int                   n_float_result_regs
  54                 = sizeof(float_result_regs)/sizeof(float_result_regs[0]);
  55         int                   n_params;
  56         int                   n_results;
  57         int                   i;
  58         int                   regnum;
  59         int                   float_regnum;
  60         calling_convention_t *cconv;
  61
  62         /* determine how parameters are passed */
  63         n_params = get_method_n_params(function_type);
  64         regnum   = 0;
  65         params   = XMALLOCNZ(reg_or_stackslot_t, n_params);
  66
  67         for (i = 0; i < n_params; ++i) {
  68                 ir_type            *param_type = get_method_param_type(function_type,i);
  69                 ir_mode            *mode       = get_type_mode(param_type);
  70                 int                 bits       = get_mode_size_bits(mode);
  71                 reg_or_stackslot_t *param      = &params[i];
  72                 param->type = param_type;
  73
  74                 if (regnum < n_param_regs) {
  75                         const arch_register_t *reg = param_regs[regnum++];
  76                         param->reg0 = reg;
  77                 } else {
  78                         param->offset = stack_offset;
  79                         /* increase offset 4 bytes so everything is aligned */
  80                         stack_offset += bits > 32 ? bits/8 : 4;
  81                         continue;
  82                 }
  83
  84                 /* we might need a 2nd 32bit component (for 64bit or double values) */
  85                 if (bits > 32) {
  86                         if (bits > 64)
  87                                 panic("only 32 and 64bit modes supported in arm backend");
  88
  89                         if (regnum < n_param_regs) {
  90                                 const arch_register_t *reg = param_regs[regnum++];
  91                                 param->reg1 = reg;
  92                         } else {
  93                                 ir_mode *mode = param_regs[0]->reg_class->mode;
  94                                 ir_type *type = get_type_for_mode(mode);
  95                                 param->type   = type;
  96                                 param->offset = stack_offset;
  97                                 assert(get_mode_size_bits(mode) == 32);
  98                                 stack_offset += 4;
  99                         }
 100                 }
 101         }
 102
 103         n_results    = get_method_n_ress(function_type);
 104         regnum       = 0;
 105         float_regnum = 0;
 106         results      = XMALLOCNZ(reg_or_stackslot_t, n_results);
 107         for (i = 0; i < n_results; ++i) {
 108                 ir_type            *result_type = get_method_res_type(function_type, i);
 109                 ir_mode            *result_mode = get_type_mode(result_type);
 110                 reg_or_stackslot_t *result      = &results[i];
 111
 112                 if (mode_is_float(result_mode)) {
 113                         if (float_regnum >= n_float_result_regs) {
 114                                 panic("Too many float results for arm backend");
 115                         } else {
 116                                 const arch_register_t *reg = float_result_regs[float_regnum++];
 117                                 result->reg0 = reg;
 118                         }
 119                 } else {
 120                         if (get_mode_size_bits(result_mode) > 32) {
 121                                 panic("Results with more than 32bits not supported by arm backend yet");
 122                         }
 123
 124                         if (regnum >= n_result_regs) {
 125                                 panic("Too many results for arm backend");
 126                         } else {
 127                                 const arch_register_t *reg = result_regs[regnum++];
 128                                 result->reg0 = reg;
 129                         }
 130                 }
 131         }
 132
 133         cconv                   = XMALLOCZ(calling_convention_t);
 134         cconv->parameters       = params;
 135         cconv->param_stack_size = stack_offset;
 136         cconv->results          = results;
 137
 138         /* setup allocatable registers */
 139         if (irg != NULL) {
 140                 be_irg_t       *birg      = be_birg_from_irg(irg);
 141                 size_t          n_ignores = ARRAY_SIZE(ignore_regs);
 142                 struct obstack *obst      = &birg->obst;
 143                 size_t          r;
 144
 145                 assert(birg->allocatable_regs == NULL);
 146                 birg->allocatable_regs = rbitset_obstack_alloc(obst, N_ARM_REGISTERS);
 147                 rbitset_set_all(birg->allocatable_regs, N_ARM_REGISTERS);
 148                 for (r = 0; r < n_ignores; ++r) {
 149                         rbitset_clear(birg->allocatable_regs, ignore_regs[r]);
 150                 }
 151         }
 152
 153         return cconv;
 154 }
 155
 156 void arm_free_calling_convention(calling_convention_t *cconv)
 157 {
 158         free(cconv->parameters);
 159         free(cconv->results);
 160         free(cconv);
 161 }