fix lower_calls sometimes not lowering method type
[libfirm] / ir / lower / lower_calls.c
index d77b69f..f51ef6a 100644 (file)
@@ -1,33 +1,18 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
- *
  * This file is part of libFirm.
- *
- * This file may be distributed and/or modified under the terms of the
- * GNU General Public License version 2 as published by the Free Software
- * Foundation and appearing in the file LICENSE.GPL included in the
- * packaging of this file.
- *
- * Licensees holding valid libFirm Professional Edition licenses may use
- * this file in accordance with the libFirm Commercial License.
- * Agreement provided with the Software.
- *
- * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
- * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE.
+ * Copyright (C) 2012 University of Karlsruhe.
  */
 
 /**
  * @file
  * @brief   Lowering of Calls with compound parameters and return types.
- * @author  Michael Beck
- * @version $Id$
+ * @author  Michael Beck, Matthias Braun
  */
-
-#ifdef HAVE_CONFIG_H
 #include "config.h"
-#endif
 
+#include <stdbool.h>
+
+#include "lower_calls.h"
 #include "lowering.h"
 #include "irprog_t.h"
 #include "irnode_t.h"
 #include "ircons.h"
 #include "irgmod.h"
 #include "irgwalk.h"
+#include "irmemory.h"
 #include "irtools.h"
 #include "iroptimize.h"
-#include "array.h"
+#include "array_t.h"
 #include "pmap.h"
-#include "xmalloc.h"
+#include "error.h"
+#include "util.h"
+
+static pmap *pointer_types;
+static pmap *lowered_mtps;
 
-/** A type map for def_find_pointer_type. */
-static pmap *type_map;
+static bool needs_lowering(const ir_type *type)
+{
+       return is_compound_type(type) || is_Array_type(type);
+}
 
 /**
  * Default implementation for finding a pointer type for a given element type.
- * Simple create a new one.
+ * Simply create a new one.
  */
-static ir_type *def_find_pointer_type(ir_type *e_type, ir_mode *mode, int alignment)
+static ir_type *get_pointer_type(ir_type *dest_type)
 {
-  ir_type *res;
-  pmap_entry *e;
-
-  /* Mode and alignment are always identical in all calls to def_find_pointer_type(), so
-     we simply can use a map from the element type to the pointer type. */
-  e = pmap_find(type_map, e_type);
-  if (e)
-    res = e->value;
-  else {
-    res = new_type_pointer(mangle_u(get_type_ident(e_type), new_id_from_chars("Ptr", 3)), e_type, mode);
-    set_type_alignment_bytes(res, alignment);
-    pmap_insert(type_map, e_type, res);
-  }
-  return res;
+       ir_type *res = pmap_get(ir_type, pointer_types, dest_type);
+       if (res == NULL) {
+               res = new_type_pointer(dest_type);
+               pmap_insert(pointer_types, dest_type, res);
+       }
+       return res;
+}
+
+static void fix_parameter_entities(ir_graph *irg, size_t n_compound_ret)
+{
+       ir_type *frame_type = get_irg_frame_type(irg);
+       size_t   n_members  = get_compound_n_members(frame_type);
+       size_t   i;
+
+       for (i = 0; i < n_members; ++i) {
+               ir_entity *member = get_compound_member(frame_type, i);
+               size_t     num;
+               if (!is_parameter_entity(member))
+                       continue;
+
+               /* increase parameter number since we added a new parameter in front */
+               num = get_entity_parameter_number(member);
+               if (num == IR_VA_START_PARAMETER_NUMBER)
+                       continue;
+               set_entity_parameter_number(member, num + n_compound_ret);
+       }
+}
+
+static void remove_compound_param_entities(ir_graph *irg)
+{
+       ir_type *frame_type = get_irg_frame_type(irg);
+       size_t   n_members  = get_compound_n_members(frame_type);
+       size_t   i;
+
+       for (i = n_members; i > 0; ) {
+               ir_entity *member = get_compound_member(frame_type, --i);
+               ir_type   *type;
+               if (!is_parameter_entity(member))
+                       continue;
+
+               type = get_entity_type(member);
+               if (needs_lowering(type)) {
+                       free_entity(member);
+               }
+       }
 }
 
 /**
  * Creates a new lowered type for a method type with compound
  * arguments. The new type is associated to the old one and returned.
- *
- * @param lp   parameter struct
- * @param mtp  the method type to lower
- *
- * The current implementation expects that a lowered type already
- * includes the necessary changes ...
  */
-static ir_type *create_modified_mtd_type(const lower_params_t *lp, ir_type *mtp)
+static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
 {
-  ir_type *lowered, *ptr_tp;
-  ir_type **params, **results, *res_tp;
-  ir_mode *modes[MAX_REGISTER_RET_VAL];
-  int n_ress, n_params, nn_ress, nn_params, i, first_variadic;
-  ident *id;
-  add_hidden hidden_params;
-  int        changed = 0;
-  variadicity var;
-
-  if (is_lowered_type(mtp)) {
-    /* the type is already lowered. Not handled yet. */
-    assert(0 && "lowered types NYI");
-  }
-
-  lowered = get_associated_type(mtp);
-  if (lowered)
-    return lowered;
-
-  n_ress   = get_method_n_ress(mtp);
-  NEW_ARR_A(ir_type *, results, n_ress);
-
-  n_params = get_method_n_params(mtp);
-  NEW_ARR_A(ir_type *, params, n_params + n_ress);
-
-  first_variadic = get_method_first_variadic_param_index(mtp);
-
-  hidden_params = lp->hidden_params;
-  if (hidden_params == ADD_HIDDEN_SMART &&
-    get_method_variadicity(mtp) == variadicity_variadic)
-        hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
-
-  if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
-    /* add hidden in front */
-    for (nn_ress = nn_params = i = 0; i < n_ress; ++i) {
-      res_tp = get_method_res_type(mtp, i);
-
-      if (is_compound_type(res_tp)) {
-        int n_regs = 0;
-
-        if (lp->flags & LF_SMALL_CMP_IN_REGS)
-          n_regs = lp->ret_compound_in_regs(res_tp, modes);
-
-        if (n_regs > 0) {
-          /* this compound will be returned solely in registers */
-          assert(0);
-        }
-        else {
-          /* this compound will be allocated on callers stack and its
-             address will be transmitted as a hidden parameter. */
-          ptr_tp = lp->find_pointer_type(res_tp, get_modeP_data(), lp->def_ptr_alignment);
-          params[nn_params++] = ptr_tp;
-          changed++;
-          if (lp->flags & LF_RETURN_HIDDEN)
-            results[nn_ress++] = ptr_tp;
-        }
-      }
-      else
-        results[nn_ress++] = res_tp;
-    }
-
-    /* move the index of the first variadic parameter */
-    first_variadic += nn_params;
-
-    for (i = 0; i < n_params; ++i)
-      params[nn_params++] = get_method_param_type(mtp, i);
-  }
-  else {
-    /* add hidden parameters last */
-    assert(get_method_variadicity(mtp) == variadicity_non_variadic &&
-      "Cannot add hidden parameters at end of variadic function");
-
-    for (nn_params = 0; nn_params < n_params; ++nn_params)
-      params[nn_params] = get_method_param_type(mtp, nn_params);
-
-    for (nn_ress = i = 0; i < n_ress; ++i) {
-      res_tp = get_method_res_type(mtp, i);
-
-      if (is_compound_type(res_tp))
-        params[nn_params++] = lp->find_pointer_type(res_tp, get_modeP_data(), lp->def_ptr_alignment);
-      else
-        results[nn_ress++] = res_tp;
-    }
-  }
-
-  /* create the new type */
-  id = mangle_u(new_id_from_chars("L", 1), get_type_ident(mtp));
-  lowered = new_d_type_method(id, nn_params, nn_ress, get_type_dbg_info(mtp));
-
-  /* fill it */
-  for (i = 0; i < nn_params; ++i)
-    set_method_param_type(lowered, i, params[i]);
-  for (i = 0; i < nn_ress; ++i)
-    set_method_res_type(lowered, i, results[i]);
-
-  var = get_method_variadicity(mtp);
-  set_method_variadicity(lowered, var);
-  if (var == variadicity_variadic)
-    set_method_first_variadic_param_index(lowered, first_variadic);
-
-  /* associate the lowered type with the original one for easier access */
-  if(changed) {
-         set_method_calling_convention(lowered,
-                         get_method_calling_convention(mtp) | cc_compound_ret);
-  }
-  set_lowered_type(mtp, lowered);
-
-  return lowered;
+       bool      must_be_lowered = false;
+       ir_type  *lowered;
+       ir_type **params;
+       ir_type **results;
+       size_t    n_ress;
+       size_t    n_params;
+       size_t    nn_ress;
+       size_t    nn_params;
+       size_t    i;
+       unsigned  cconv;
+       mtp_additional_properties mtp_properties;
+
+       if (!is_Method_type(mtp))
+               return mtp;
+
+       lowered = pmap_get(ir_type, lowered_mtps, mtp);
+       if (lowered != NULL)
+               return lowered;
+
+       /* check if the type has to be lowered at all */
+       n_params = get_method_n_params(mtp);
+       n_ress   = get_method_n_ress(mtp);
+       for (i = 0; i < n_ress; ++i) {
+               ir_type *res_tp = get_method_res_type(mtp, i);
+               if (needs_lowering(res_tp)) {
+                       must_be_lowered = true;
+                       break;
+               }
+       }
+       if (!must_be_lowered && !(flags & LF_DONT_LOWER_ARGUMENTS)) {
+               for (i = 0; i < n_params; ++i) {
+                       ir_type *param_type = get_method_param_type(mtp, i);
+                       if (needs_lowering(param_type)) {
+                               must_be_lowered = true;
+                               break;
+                       }
+               }
+       }
+       if (!must_be_lowered)
+               return mtp;
+
+       results   = ALLOCANZ(ir_type*, n_ress);
+       params    = ALLOCANZ(ir_type*, n_params + n_ress);
+       nn_ress   = 0;
+       nn_params = 0;
+
+       /* add a hidden parameter in front for every compound result */
+       for (i = 0; i < n_ress; ++i) {
+               ir_type *res_tp = get_method_res_type(mtp, i);
+
+               if (needs_lowering(res_tp)) {
+                       /* this compound will be allocated on callers stack and its
+                          address will be transmitted as a hidden parameter. */
+                       ir_type *ptr_tp = get_pointer_type(res_tp);
+                       params[nn_params++] = ptr_tp;
+                       if (flags & LF_RETURN_HIDDEN)
+                               results[nn_ress++] = ptr_tp;
+               } else {
+                       /* scalar result */
+                       results[nn_ress++] = res_tp;
+               }
+       }
+       /* copy over parameter types */
+       for (i = 0; i < n_params; ++i) {
+               ir_type *param_type = get_method_param_type(mtp, i);
+               if (! (flags & LF_DONT_LOWER_ARGUMENTS) && needs_lowering(param_type)) {
+                   /* turn parameter into a pointer type */
+                   param_type = new_type_pointer(param_type);
+               }
+               params[nn_params++] = param_type;
+       }
+       assert(nn_ress <= n_ress);
+       assert(nn_params <= n_params + n_ress);
+
+       /* create the new type */
+       lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
+
+       /* fill it */
+       for (i = 0; i < nn_params; ++i)
+               set_method_param_type(lowered, i, params[i]);
+       for (i = 0; i < nn_ress; ++i)
+               set_method_res_type(lowered, i, results[i]);
+
+       set_method_variadicity(lowered, get_method_variadicity(mtp));
+
+       cconv = get_method_calling_convention(mtp);
+       if (nn_params > n_params) {
+               cconv |= cc_compound_ret;
+       }
+       set_method_calling_convention(lowered, cconv);
+
+       mtp_properties = get_method_additional_properties(mtp);
+       /* after lowering the call is not const anymore, since it writes to the
+        * memory for the return value passed to it */
+       mtp_properties &= ~mtp_property_const;
+       set_method_additional_properties(lowered, mtp_properties);
+
+       /* associate the lowered type with the original one for easier access */
+       set_higher_type(lowered, mtp);
+       pmap_insert(lowered_mtps, mtp, lowered);
+
+       return lowered;
 }
 
 /**
@@ -193,22 +205,24 @@ static ir_type *create_modified_mtd_type(const lower_params_t *lp, ir_type *mtp)
  */
 typedef struct cl_entry cl_entry;
 struct cl_entry {
-  cl_entry *next;   /**< Pointer to the next entry. */
-  ir_node  *call;   /**< Pointer to the Call node. */
-  ir_node  *copyb;  /**< List of all CopyB nodes. */
+       cl_entry *next;   /**< Pointer to the next entry. */
+       ir_node  *call;   /**< Pointer to the Call node. */
+       ir_node  *copyb;  /**< List of all CopyB nodes. */
+       bool      has_compound_ret   : 1;
+       bool      has_compound_param : 1;
 };
 
 /**
  * Walker environment for fix_args_and_collect_calls().
  */
-typedef struct _wlk_env_t {
-  int                  arg_shift;     /**< The Argument index shift for parameters. */
-  int                  first_hidden;  /**< The index of the first hidden argument. */
-  struct obstack       obst;          /**< An obstack to allocate the data on. */
-  cl_entry             *cl_list;      /**< The call list. */
-  pmap                 *dummy_map;    /**< A map for finding the dummy arguments. */
-  unsigned             dnr;           /**< The dummy index number. */
-  const lower_params_t *params;       /**< lowering parameters */
+typedef struct wlk_env_t {
+       size_t               arg_shift;        /**< The Argument index shift for parameters. */
+       struct obstack       obst;             /**< An obstack to allocate the data on. */
+       cl_entry             *cl_list;         /**< The call list. */
+       compound_call_lowering_flags flags;
+       ir_type              *lowered_mtp;     /**< The lowered method type of the current irg if any. */
+       bool                  only_local_mem:1;/**< Set if only local memory access was found. */
+       bool                  changed:1;       /**< Set if the current graph was changed. */
 } wlk_env;
 
 /**
@@ -219,87 +233,204 @@ typedef struct _wlk_env_t {
  * @param call   A Call node.
  * @param env    The environment.
  */
-static cl_entry *get_Call_entry(ir_node *call, wlk_env *env) {
-  cl_entry *res = get_irn_link(call);
-  if (res == NULL) {
-    cl_entry *res = obstack_alloc(&env->obst, sizeof(*res));
-    res->next  = env->cl_list;
-    res->call  = call;
-    res->copyb = NULL;
-    set_irn_link(call, res);
-    env->cl_list = res;
-  }
-  return res;
+static cl_entry *get_call_entry(ir_node *call, wlk_env *env)
+{
+       cl_entry *res = (cl_entry*)get_irn_link(call);
+       if (res == NULL) {
+               res = OALLOC(&env->obst, cl_entry);
+               res->next  = env->cl_list;
+               res->call  = call;
+               res->copyb = NULL;
+               set_irn_link(call, res);
+               env->cl_list = res;
+       }
+       return res;
+}
+
+/**
+ * Finds the base address of an address by skipping Sel's and address
+ * calculation.
+ *
+ * @param adr   the address
+ * @param pEnt  points to the base entity if any
+ */
+static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
+{
+       ir_entity *ent = NULL;
+       assert(mode_is_reference(get_irn_mode(ptr)));
+
+       for (;;) {
+               if (is_Sel(ptr)) {
+                       ent = get_Sel_entity(ptr);
+                       ptr = get_Sel_ptr(ptr);
+               }
+               else if (is_Add(ptr)) {
+                       ir_node *left = get_Add_left(ptr);
+                       if (mode_is_reference(get_irn_mode(left)))
+                               ptr = left;
+                       else
+                               ptr = get_Add_right(ptr);
+                       ent = NULL;
+               } else if (is_Sub(ptr)) {
+                       ptr = get_Sub_left(ptr);
+                       ent = NULL;
+               } else {
+                       *pEnt = ent;
+                       return ptr;
+               }
+       }
+}
+
+/**
+ * Check if a given pointer represents non-local memory.
+ */
+static void check_ptr(ir_node *ptr, wlk_env *env)
+{
+       ir_storage_class_class_t sc;
+       ir_entity                *ent;
+
+       /* still alias free */
+       ptr = find_base_adr(ptr, &ent);
+       sc  = get_base_sc(classify_pointer(ptr, ent));
+       if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
+               /* non-local memory access */
+               env->only_local_mem = false;
+       }
+}
+
+/*
+ * Returns non-zero if a Call is surely a self-recursive Call.
+ * Beware: if this functions returns 0, the call might be self-recursive!
+ */
+static bool is_self_recursive_Call(const ir_node *call)
+{
+       const ir_node *callee = get_Call_ptr(call);
+
+       if (is_SymConst_addr_ent(callee)) {
+               const ir_entity *ent = get_SymConst_entity(callee);
+               const ir_graph  *irg = get_entity_irg(ent);
+               if (irg == get_irn_irg(call))
+                       return true;
+       }
+       return false;
 }
 
 /**
- * Post walker: shift all parameter indeces
+ * Post walker: shift all parameter indexes
  * and collect Calls with compound returns in the call list.
+ * If a non-alias free memory access is found, reset the alias free
+ * flag.
  */
-static void fix_args_and_collect_calls(ir_node *n, void *ctx) {
-  wlk_env *env = ctx;
-  int i;
-  ir_type *ctp;
-  ir_op *op = get_irn_op(n);
-
-  if (env->arg_shift > 0 && op == op_Proj) {
-    ir_node *pred = get_Proj_pred(n);
-
-    /* Fix the argument numbers */
-    if (pred == get_irg_args(current_ir_graph)) {
-      long pnr = get_Proj_proj(n);
-      set_Proj_proj(n, pnr + env->arg_shift);
-    }
-  }
-  else if (op == op_Call) {
-    ctp = get_Call_type(n);
-    if (env->params->flags & LF_COMPOUND_RETURN) {
-      /* check for compound returns */
-      for (i = get_method_n_ress(ctp) -1; i >= 0; --i) {
-        if (is_compound_type(get_method_res_type(ctp, i))) {
-          /*
-           * This is a call with a compound return. As the result
-           * might be ignored, we must put it in the list.
-           */
-          (void)get_Call_entry(n, env);
-          break;
-        }
-      }
-    }
-  }
-  else if (op == op_CopyB && env->params->flags & LF_COMPOUND_RETURN) {
-    /* check for compound returns */
-    ir_node *src = get_CopyB_src(n);
-    /* older scheme using value_res_ent */
-    if (is_Sel(src)) {
-      ir_node *proj = get_Sel_ptr(src);
-      if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_P_value_res_base) {
-        ir_node *call = get_Proj_pred(proj);
-        if (is_Call(call)) {
-          /* found a CopyB from compound Call result */
-          cl_entry *e = get_Call_entry(call, env);
-          set_irn_link(n, e->copyb);
-          e->copyb = n;
-        }
-      }
-    } else
-    /* new scheme: compound results are determined by the call type only */
-    if (is_Proj(src)) {
-      ir_node *proj = get_Proj_pred(src);
-      if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
-        ir_node *call = get_Proj_pred(proj);
-        if (is_Call(call)) {
-          ctp = get_Call_type(call);
-          if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
-            /* found a CopyB from compound Call result */
-            cl_entry *e = get_Call_entry(call, env);
-            set_irn_link(n, e->copyb);
-            e->copyb = n;
-          }
-        }
-      }
-    }
-  }
+static void fix_args_and_collect_calls(ir_node *n, void *ctx)
+{
+       wlk_env *env = (wlk_env*)ctx;
+       ir_node *ptr;
+
+       switch (get_irn_opcode(n)) {
+       case iro_Load:
+       case iro_Store:
+               if (env->only_local_mem) {
+                       ptr = get_irn_n(n, 1);
+                       check_ptr(ptr, env);
+               }
+               break;
+       case iro_Proj:
+               if (env->arg_shift > 0) {
+                       ir_node *pred = get_Proj_pred(n);
+                       ir_graph *irg = get_irn_irg(n);
+
+                       /* Fix the argument numbers */
+                       if (pred == get_irg_args(irg)) {
+                               long pnr = get_Proj_proj(n);
+                               set_Proj_proj(n, pnr + env->arg_shift);
+                               env->changed = true;
+                       }
+               }
+               break;
+       case iro_Call: {
+               ir_type *ctp      = get_Call_type(n);
+               size_t   n_ress   = get_method_n_ress(ctp);
+               size_t   n_params = get_method_n_params(ctp);
+               size_t   i;
+               if (! is_self_recursive_Call(n)) {
+                       /* any non self recursive call might access global memory */
+                       env->only_local_mem = false;
+               }
+
+               /* check for compound returns */
+               for (i = 0; i < n_ress; ++i) {
+                       ir_type *type = get_method_res_type(ctp, i);
+                       if (needs_lowering(type)) {
+                               /*
+                                * This is a call with a compound return. As the result
+                                * might be ignored, we must put it in the list.
+                                */
+                               cl_entry *entry = get_call_entry(n, env);
+                               entry->has_compound_ret = true;
+                               break;
+                       }
+               }
+               for (i = 0; i < n_params; ++i) {
+                       ir_type *type = get_method_param_type(ctp, i);
+                       if (needs_lowering(type)) {
+                               cl_entry *entry = get_call_entry(n, env);
+                               entry->has_compound_param = true;
+                               break;
+                       }
+               }
+               break;
+       }
+       case iro_CopyB: {
+               ir_node *src = get_CopyB_src(n);
+               if (env->only_local_mem) {
+                       check_ptr(get_CopyB_src(n), env);
+                       if (env->only_local_mem)
+                               check_ptr(get_CopyB_dst(n), env);
+               }
+               /* check for compound returns */
+               if (is_Proj(src)) {
+                       ir_node *proj = get_Proj_pred(src);
+                       if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
+                               ir_node *call = get_Proj_pred(proj);
+                               if (is_Call(call)) {
+                                       ir_type *ctp = get_Call_type(call);
+                                       if (needs_lowering(get_method_res_type(ctp, get_Proj_proj(src)))) {
+                                               /* found a CopyB from compound Call result */
+                                               cl_entry *e = get_call_entry(call, env);
+                                               set_irn_link(n, e->copyb);
+                                               e->copyb = n;
+                                       }
+                               }
+                       }
+               }
+               break;
+       }
+       case iro_Sel: {
+               ir_entity *entity = get_Sel_entity(n);
+               ir_type   *type   = get_entity_type(entity);
+
+               if (is_parameter_entity(entity) && needs_lowering(type)) {
+                       if (! (env->flags & LF_DONT_LOWER_ARGUMENTS)) {
+                               /* note that num was already modified by fix_parameter_entities
+                                * so no need to add env->arg_shift again */
+                               size_t num = get_entity_parameter_number(entity);
+                               ir_graph *irg  = get_irn_irg(n);
+                               ir_node  *args = get_irg_args(irg);
+                               ir_node  *ptr  = new_r_Proj(args, mode_P, num);
+                               exchange(n, ptr);
+                               /* hack to avoid us visiting the proj again */
+                               mark_irn_visited(ptr);
+                       }
+
+                       /* we need to copy compound parameters */
+                       env->only_local_mem = false;
+               }
+               break;
+       }
+       default:
+               /* do nothing */
+               break;
+       }
 }
 
 /**
@@ -309,211 +440,220 @@ static void fix_args_and_collect_calls(ir_node *n, void *ctx) {
  * @param ft   the frame type
  * @param adr  the node
  */
-static int is_compound_address(ir_type *ft, ir_node *adr)
+static bool is_compound_address(ir_type *ft, ir_node *adr)
 {
-  ir_entity *ent;
-
-  if (! is_Sel(adr))
-    return 0;
-  if (get_Sel_n_indexs(adr) != 0)
-    return 0;
-  ent = get_Sel_entity(adr);
-  return get_entity_owner(ent) == ft;
+       ir_entity *ent;
+
+       if (! is_Sel(adr))
+               return false;
+       if (get_Sel_n_indexs(adr) != 0)
+               return false;
+       ent = get_Sel_entity(adr);
+       return get_entity_owner(ent) == ft;
 }
 
 /** A pair for the copy-return-optimization. */
 typedef struct cr_pair {
-  ir_entity *ent; /**< the entity than can be removed from the frame */
-  ir_node *arg;   /**< the argument that replaces the entities address */
+       ir_entity *ent; /**< the entity than can be removed from the frame */
+       ir_node *arg;   /**< the argument that replaces the entities address */
 } cr_pair;
 
 /**
  * Post walker: fixes all entities addresses for the copy-return
  * optimization.
  *
- * Note: We expect the length of the cr_pair array (ie number of compound
+ * Note: We expect the length of the cr_pair array (i.e. number of compound
  * return values) to be 1 (C, C++) in almost all cases, so ignore the
  * linear search complexity here.
  */
-static void do_copy_return_opt(ir_node *n, void *ctx) {
-  cr_pair *arr = ctx;
-  int i;
-
-  if (is_Sel(n)) {
-    ir_entity *ent = get_Sel_entity(n);
-
-    for (i = ARR_LEN(arr) - 1; i >= 0; --i) {
-      if (ent == arr[i].ent) {
-        exchange(n, arr[i].arg);
-        break;
-      }
-    }
-  }
+static void do_copy_return_opt(ir_node *n, void *ctx)
+{
+       if (is_Sel(n)) {
+               ir_entity *ent = get_Sel_entity(n);
+               cr_pair   *arr = (cr_pair*)ctx;
+               size_t    i, l;
+
+               for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
+                       if (ent == arr[i].ent) {
+                               exchange(n, arr[i].arg);
+                               break;
+                       }
+               }
+       }
 }
 
 /**
  * Return a Sel node that selects a dummy argument of type tp.
- * Dummy arguments are only needed once and we use a map
- * to store them.
- * We could even assign all dummy arguments the same offset
- * in the frame type ...
  *
  * @param irg    the graph
  * @param block  the block where a newly create Sel should be placed
  * @param tp     the type of the dummy entity that should be create
- * @param env    the environment
  */
-static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp, wlk_env *env)
+static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp)
 {
-  ir_entity *ent;
-  pmap_entry *e;
-
-  /* use a map the check if we already create such an entity */
-  e = pmap_find(env->dummy_map, tp);
-  if (e)
-    ent = e->value;
-  else {
-    ir_type *ft = get_irg_frame_type(irg);
-    char buf[16];
-
-    snprintf(buf, sizeof(buf), "dummy.%u", env->dnr++);
-    ent = new_entity(ft, new_id_from_str(buf), tp);
-    pmap_insert(env->dummy_map, tp, ent);
-
-    if (get_type_state(ft) == layout_fixed) {
-      /* Fix the layout again */
-      assert(0 && "Fixed layout not implemented");
-    }
-  }
-  return new_r_simpleSel(
-    irg,
-    block,
-    get_irg_no_mem(irg),
-    get_irg_frame(irg),
-    ent);
+       ir_type   *ft       = get_irg_frame_type(irg);
+       ident     *dummy_id = id_unique("dummy.%u");
+       ir_entity *ent      = new_entity(ft, dummy_id, tp);
+
+       if (get_type_state(ft) == layout_fixed) {
+               /* Fix the layout again */
+               panic("Fixed layout not implemented");
+       }
+
+       return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
 }
 
 /**
  * Add the hidden parameter from the CopyB node to the Call node.
- *
- * @param irg    the graph
- * @param n_com  number of compound results (will be number of hidden parameters)
- * @param ins    in array to store the hidden parameters into
- * @param entry  the call list
- * @param env    the environment
  */
-static void add_hidden_param(ir_graph *irg, int n_com, ir_node **ins, cl_entry *entry, wlk_env *env)
+static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
+                             cl_entry *entry, ir_type *ctp)
 {
-  ir_node *p, *n, *src, *mem, *blk;
-  ir_entity *ent;
-  ir_type *owner;
-  int idx, n_args;
-
-  n_args = 0;
-  for (p = entry->copyb; p; p = n) {
-    n   = get_irn_link(p);
-    src = get_CopyB_src(p);
-
-    /* old scheme using value_res_ent */
-    if (is_Sel(src)) {
-      ent = get_Sel_entity(src);
-      owner = get_entity_owner(ent);
-
-      /* find the hidden parameter index */
-      for (idx = 0; idx < get_struct_n_members(owner); ++idx)
-        if (get_struct_member(owner, idx) == ent)
-          break;
-      assert(idx < get_struct_n_members(owner));
-    }
-    else
-
-    /* new scheme: compound returns are determined by the call type and are Proj's */
-    idx = get_Proj_proj(src);
-
-    ins[idx] = get_CopyB_dst(p);
-    mem      = get_CopyB_mem(p);
-    blk      = get_nodes_block(p);
-
-    /* get rid of the CopyB */
-    turn_into_tuple(p, pn_CopyB_max);
-    set_Tuple_pred(p, pn_CopyB_M_regular, mem);
-    set_Tuple_pred(p, pn_CopyB_M_except,  get_irg_bad(irg));
-    set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(irg, blk));
-    set_Tuple_pred(p, pn_CopyB_X_except,  get_irg_bad(irg));
-    ++n_args;
-  }
-
-  /* now create dummy entities for function with ignored return value */
-  if (n_args < n_com) {
-    ir_type *ctp = get_Call_type(entry->call);
-    int i, j;
-
-    if (is_lowered_type(ctp))
-      ctp = get_associated_type(ctp);
-
-    for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
-      ir_type *rtp = get_method_res_type(ctp, i);
-      if (is_compound_type(rtp)) {
-        if (ins[j] == NULL)
-          ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
-        ++j;
-      }
-    }
-  }
+       ir_node *p, *n;
+       size_t n_args;
+
+       n_args = 0;
+       for (p = entry->copyb; p; p = n) {
+               ir_node *src = get_CopyB_src(p);
+               size_t   idx = get_Proj_proj(src);
+               n = (ir_node*)get_irn_link(p);
+
+               /* consider only the first CopyB */
+               if (ins[idx] == NULL) {
+                       ir_node *block = get_nodes_block(p);
+
+                       /* use the memory output of the call and not the input of the CopyB
+                        * otherwise stuff breaks if the call was mtp_property_const, because
+                        * then the copyb skips the call. But after lowering the call is not
+                        * const anymore, and its memory has to be used */
+                       ir_node *mem = new_r_Proj(entry->call, mode_M, pn_Call_M);
+
+                       ins[idx] = get_CopyB_dst(p);
+
+                       /* get rid of the CopyB */
+                       if (ir_throws_exception(p)) {
+                               ir_node *const in[] = {
+                                       [pn_CopyB_M]         = mem,
+                                       [pn_CopyB_X_regular] = new_r_Jmp(block),
+                                       [pn_CopyB_X_except]  = new_r_Bad(irg, mode_X),
+                               };
+                               turn_into_tuple(p, ARRAY_SIZE(in), in);
+                       } else {
+                               ir_node *const in[] = { mem };
+                               turn_into_tuple(p, ARRAY_SIZE(in), in);
+                       }
+                       ++n_args;
+               }
+       }
+
+       /* now create dummy entities for function with ignored return value */
+       if (n_args < n_com) {
+               size_t i;
+               size_t j;
+
+               for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
+                       ir_type *rtp = get_method_res_type(ctp, i);
+                       if (needs_lowering(rtp)) {
+                               if (ins[j] == NULL)
+                                       ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp);
+                               ++j;
+                       }
+               }
+       }
 }
 
-/**
- * Fix all calls on a call list by adding hidden parameters.
- *
- * @param irg  the graph
- * @param env  the environment
- */
-static void fix_call_list(ir_graph *irg, wlk_env *env) {
-  const lower_params_t *lp = env->params;
-  cl_entry *p;
-  ir_node *call, **new_in;
-  ir_type *ctp, *lowered_mtp;
-  add_hidden hidden_params;
-  int i, n_params, n_com, pos;
-
-  new_in = NEW_ARR_F(ir_node *, 0);
-  for (p = env->cl_list; p; p = p->next) {
-    call = p->call;
-    ctp = get_Call_type(call);
-    lowered_mtp = create_modified_mtd_type(lp, ctp);
-    set_Call_type(call, lowered_mtp);
-
-    hidden_params = lp->hidden_params;
-    if (hidden_params == ADD_HIDDEN_SMART &&
-      get_method_variadicity(ctp) == variadicity_variadic)
-      hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
-
-    n_params = get_Call_n_params(call);
-
-    n_com = 0;
-    for (i = get_method_n_ress(ctp) - 1; i >= 0; --i) {
-      if (is_compound_type(get_method_res_type(ctp, i)))
-        ++n_com;
-    }
-    pos = 2;
-    ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
-    memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
-    if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
-      add_hidden_param(irg, n_com, &new_in[pos], p, env);
-      pos += n_com;
-    }
-    /* copy all other parameters */
-    for (i = 0; i < n_params; ++i)
-      new_in[pos++] = get_Call_param(call, i);
-    if (hidden_params == ADD_HIDDEN_ALWAYS_LAST) {
-      add_hidden_param(irg, n_com, &new_in[pos], p, env);
-      pos += n_com;
-    }
-    new_in[0] = get_Call_mem(call);
-    new_in[1] = get_Call_ptr(call);
-
-    set_irn_in(call, n_params + n_com + 2, new_in);
-  }
+static void fix_compound_ret(cl_entry *entry, ir_type *ctp)
+{
+       ir_node  *call     = entry->call;
+       ir_graph *irg      = get_irn_irg(call);
+       size_t    n_params = get_Call_n_params(call);
+       size_t    n_com    = 0;
+       size_t    n_res    = get_method_n_ress(ctp);
+       size_t    pos      = 0;
+       ir_node **new_in;
+       size_t    i;
+
+       for (i = 0; i < n_res; ++i) {
+               ir_type *type = get_method_res_type(ctp, i);
+               if (needs_lowering(type))
+                       ++n_com;
+       }
+
+       new_in = ALLOCANZ(ir_node*, n_params + n_com + (n_Call_max+1));
+       new_in[pos++] = get_Call_mem(call);
+       new_in[pos++] = get_Call_ptr(call);
+       assert(pos == n_Call_max+1);
+       add_hidden_param(irg, n_com, &new_in[pos], entry, ctp);
+       pos += n_com;
+
+       /* copy all other parameters */
+       for (i = 0; i < n_params; ++i) {
+               ir_node *param = get_Call_param(call, i);
+               new_in[pos++] = param;
+       }
+       assert(pos == n_params+n_com+(n_Call_max+1));
+       set_irn_in(call, pos, new_in);
+}
+
+static ir_entity *create_compound_arg_entity(ir_graph *irg, ir_type *type)
+{
+       ir_type   *frame  = get_irg_frame_type(irg);
+       ident     *id     = id_unique("$compound_param.%u");
+       ir_entity *entity = new_entity(frame, id, type);
+       /* TODO:
+        * we could do some optimisations here and create a big union type for all
+        * different call types in a function */
+       return entity;
+}
+
+static void fix_compound_params(cl_entry *entry, ir_type *ctp)
+{
+       ir_node  *call     = entry->call;
+       dbg_info *dbgi     = get_irn_dbg_info(call);
+       ir_node  *mem      = get_Call_mem(call);
+       ir_graph *irg      = get_irn_irg(call);
+       ir_node  *nomem    = new_r_NoMem(irg);
+       ir_node  *frame    = get_irg_frame(irg);
+       size_t    n_params = get_method_n_params(ctp);
+       size_t    i;
+
+       for (i = 0; i < n_params; ++i) {
+               ir_type   *type = get_method_param_type(ctp, i);
+               ir_node   *block;
+               ir_node   *arg;
+               ir_node   *sel;
+               ir_node   *copyb;
+               ir_entity *arg_entity;
+               if (!needs_lowering(type))
+                       continue;
+
+               arg        = get_Call_param(call, i);
+               arg_entity = create_compound_arg_entity(irg, type);
+               block      = get_nodes_block(call);
+               sel        = new_rd_simpleSel(dbgi, block, nomem, frame, arg_entity);
+               copyb      = new_rd_CopyB(dbgi, block, mem, sel, arg, type);
+               mem        = new_r_Proj(copyb, mode_M, pn_CopyB_M);
+               set_Call_param(call, i, sel);
+       }
+       set_Call_mem(call, mem);
+}
+
+static void fix_calls(wlk_env *env)
+{
+       cl_entry *entry;
+       for (entry = env->cl_list; entry; entry = entry->next) {
+               ir_node *call        = entry->call;
+               ir_type *ctp         = get_Call_type(call);
+               ir_type *lowered_mtp = lower_mtp(env->flags, ctp);
+               set_Call_type(call, lowered_mtp);
+
+               if (entry->has_compound_param) {
+                       fix_compound_params(entry, ctp);
+               }
+               if (entry->has_compound_ret) {
+                       fix_compound_ret(entry, ctp);
+               }
+       }
 }
 
 /**
@@ -522,259 +662,212 @@ static void fix_call_list(ir_graph *irg, wlk_env *env) {
  * If it calls methods with compound parameter returns, add hidden
  * parameters.
  *
- * @param lp   parameter struct
  * @param irg  the graph to transform
  */
-static void transform_irg(const lower_params_t *lp, ir_graph *irg)
+static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
 {
-  ir_entity *ent = get_irg_entity(irg);
-  ir_type *mtp, *lowered_mtp, *tp, *ft;
-  int i, j, k, n_ress = 0, n_ret_com = 0, n_cr_opt;
-  ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
-  cr_pair *cr_opt;
-  wlk_env env;
-  add_hidden hidden_params;
-
-  assert(ent && "Cannot tranform graph without an entity");
-  assert(get_irg_phase_state(irg) == phase_high && "call lowering must be done in phase high");
-
-  mtp = get_entity_type(ent);
-
-  if (lp->flags & LF_COMPOUND_RETURN) {
-    /* calculate the number of compound returns */
-    n_ress = get_method_n_ress(mtp);
-    for (n_ret_com = i = 0; i < n_ress; ++i) {
-      tp = get_method_res_type(mtp, i);
-
-      if (is_compound_type(tp))
-        ++n_ret_com;
-    }
-  }
-
-  if (n_ret_com) {
-    /* much easier if we have only one return */
-    normalize_one_return(irg);
-
-    /* This graph has a compound argument. Create a new type */
-    lowered_mtp = create_modified_mtd_type(lp, mtp);
-    set_entity_type(ent, lowered_mtp);
-
-    hidden_params = lp->hidden_params;
-    if (hidden_params == ADD_HIDDEN_SMART &&
-      get_method_variadicity(mtp) == variadicity_variadic)
-      hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
-
-    if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
-      /* hidden arguments are added first */
-      env.arg_shift    = n_ret_com;
-      env.first_hidden = 0;
-    }
-    else {
-      /* hidden arguments are added last */
-      env.arg_shift    = 0;
-      env.first_hidden = get_method_n_params(mtp);
-    }
-  }
-  else {
-    /* we must only search for calls */
-    env.arg_shift = 0;
-  }
-  obstack_init(&env.obst);
-  env.cl_list   = NULL;
-  env.dummy_map = pmap_create_ex(8);
-  env.dnr       = 0;
-  env.params    = lp;
-
-  /* scan the code, fix argument numbers and collect calls. */
-  irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
-
-  /* fix all calls */
-  if (env.cl_list)
-    fix_call_list(irg, &env);
-
-  if (n_ret_com) {
-    /*
-     * Now fix the Return node of the current graph.
-     */
-
-    /* STEP 1: find the return. This is simple, we have normalized the graph. */
-    endbl = get_irg_end_block(irg);
-    ret = NULL;
-    for (i = get_Block_n_cfgpreds(endbl) - 1; i >= 0; --i) {
-      ir_node *pred = get_Block_cfgpred(endbl, i);
-
-      if (is_Return(pred)) {
-        ret = pred;
-        break;
-      }
-    }
-    /* there should always be a return */
-    assert(ret);
-
-    /*
-     * STEP 2: fix it. For all compound return values add a CopyB,
-     * all others are copied.
-     */
-    NEW_ARR_A(ir_node *, new_in, n_ress + 1);
-
-    bl  = get_nodes_block(ret);
-    mem = get_Return_mem(ret);
-
-    ft = get_irg_frame_type(irg);
-    NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
-    n_cr_opt = 0;
-    for (j = 1, i = k = 0; i < n_ress; ++i) {
-      ir_node *pred = get_Return_res(ret, i);
-      tp = get_method_res_type(mtp, i);
-
-      if (is_compound_type(tp)) {
-        ir_node *arg = get_irg_args(irg);
-        arg = new_r_Proj(irg, get_nodes_block(arg), arg, mode_P_data, env.first_hidden + k);
-        ++k;
-
-        if (is_compound_address(ft, pred)) {
-          /* we can do the copy-return optimization here */
-          cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
-          cr_opt[n_cr_opt].arg = arg;
-          ++n_cr_opt;
-        }
-        else { /* copy-return optimization is impossible, do the copy. */
-          copy = new_r_CopyB(
-                  irg, bl,
-                  mem,
-                  arg,
-                  pred,
-                  tp
-                 );
-          mem = new_r_Proj(irg, bl, copy, mode_M, pn_CopyB_M_regular);
-        }
-        if (lp->flags & LF_RETURN_HIDDEN) {
-          new_in[j] = arg;
-          ++j;
-        }
-      }
-      else { /* scalar return value */
-        new_in[j] = pred;
-        ++j;
-      }
-    }
-    /* replace the in of the Return */
-    new_in[0] = mem;
-    set_irn_in(ret, j, new_in);
-
-    if (n_cr_opt > 0) {
-      irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
-
-      for (i = ARR_LEN(cr_opt) - 1; i >= 0; --i) {
-        remove_class_member(ft, cr_opt[i].ent);
-      }
-    }
-  } /* if (n_ret_com) */
-
-  pmap_destroy(env.dummy_map);
-  obstack_free(&env.obst, NULL);
+       ir_entity *ent         = get_irg_entity(irg);
+       ir_type   *mtp         = get_entity_type(ent);
+       size_t     n_ress      = get_method_n_ress(mtp);
+       size_t     n_params    = get_method_n_params(mtp);
+       size_t     n_param_com = 0;
+
+       ir_type   *lowered_mtp, *tp, *ft;
+       size_t    i, j, k;
+       size_t    n_cr_opt;
+       ir_node   **new_in, *ret, *endbl, *bl, *mem, *copy;
+       cr_pair   *cr_opt;
+       wlk_env   env;
+
+       /* calculate the number of compound returns */
+       size_t n_ret_com = 0;
+       for (i = 0; i < n_ress; ++i) {
+               ir_type *type = get_method_res_type(mtp, i);
+               if (needs_lowering(type))
+                       ++n_ret_com;
+       }
+       for (i = 0; i < n_params; ++i) {
+               ir_type *type = get_method_param_type(mtp, i);
+               if (needs_lowering(type))
+                       ++n_param_com;
+       }
+
+       if (n_ret_com > 0)
+               fix_parameter_entities(irg, n_ret_com);
+
+       if (n_ret_com) {
+               /* much easier if we have only one return */
+               normalize_one_return(irg);
+
+               /* hidden arguments are added first */
+               env.arg_shift = n_ret_com;
+       } else {
+               /* we must only search for calls */
+               env.arg_shift = 0;
+               lowered_mtp   = NULL;
+       }
+
+       lowered_mtp = lower_mtp(flags, mtp);
+       set_entity_type(ent, lowered_mtp);
+
+       obstack_init(&env.obst);
+       env.cl_list        = NULL;
+       env.flags          = flags;
+       env.lowered_mtp    = lowered_mtp;
+       env.only_local_mem = true;
+       env.changed        = false;
+
+       /* scan the code, fix argument numbers and collect calls. */
+       irg_walk_graph(irg, firm_clear_link, NULL, &env);
+       irg_walk_graph(irg, fix_args_and_collect_calls, NULL, &env);
+
+       if (n_param_com > 0 && !(flags & LF_DONT_LOWER_ARGUMENTS))
+               remove_compound_param_entities(irg);
+
+       /* fix all calls */
+       if (env.cl_list != NULL) {
+               fix_calls(&env);
+               env.changed = true;
+       }
+
+       if (n_ret_com) {
+               int idx;
+
+               /* STEP 1: find the return. This is simple, we have normalized the graph. */
+               endbl = get_irg_end_block(irg);
+               ret = NULL;
+               for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
+                       ir_node *pred = get_Block_cfgpred(endbl, idx);
+
+                       if (is_Return(pred)) {
+                               ret = pred;
+                               break;
+                       }
+               }
+
+               /* in case of infinite loops, there might be no return */
+               if (ret != NULL) {
+                       /*
+                        * Now fix the Return node of the current graph.
+                        */
+                       env.changed = true;
+
+                       /*
+                        * STEP 2: fix it. For all compound return values add a CopyB,
+                        * all others are copied.
+                        */
+                       NEW_ARR_A(ir_node *, new_in, n_ress + 1);
+
+                       bl  = get_nodes_block(ret);
+                       mem = get_Return_mem(ret);
+
+                       ft = get_irg_frame_type(irg);
+                       NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
+                       n_cr_opt = 0;
+                       for (j = 1, i = k = 0; i < n_ress; ++i) {
+                               ir_node *pred = get_Return_res(ret, i);
+                               tp = get_method_res_type(mtp, i);
+
+                               if (needs_lowering(tp)) {
+                                       ir_node *arg = get_irg_args(irg);
+                                       arg = new_r_Proj(arg, mode_P_data, k);
+                                       ++k;
+
+                                       if (is_Unknown(pred)) {
+                                               /* The Return(Unknown) is the Firm construct for a
+                                                * missing return. Do nothing. */
+                                       } else {
+                                               /**
+                                                * Sorrily detecting that copy-return is possible isn't
+                                                * that simple. We must check, that the hidden address
+                                                * is alias free during the whole function.
+                                                * A simple heuristic: all Loads/Stores inside
+                                                * the function access only local frame.
+                                                */
+                                               if (env.only_local_mem && is_compound_address(ft, pred)) {
+                                                       /* we can do the copy-return optimization here */
+                                                       cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
+                                                       cr_opt[n_cr_opt].arg = arg;
+                                                       ++n_cr_opt;
+                                               } else { /* copy-return optimization is impossible, do the copy. */
+                                                       copy = new_r_CopyB(
+                                                                       bl,
+                                                                       mem,
+                                                                       arg,
+                                                                       pred,
+                                                                       tp
+                                                                       );
+                                                       mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
+                                               }
+                                       }
+                                       if (flags & LF_RETURN_HIDDEN) {
+                                               new_in[j] = arg;
+                                               ++j;
+                                       }
+                               } else { /* scalar return value */
+                                       new_in[j] = pred;
+                                       ++j;
+                               }
+                       }
+                       /* replace the in of the Return */
+                       new_in[0] = mem;
+                       set_irn_in(ret, j, new_in);
+
+                       if (n_cr_opt > 0) {
+                               size_t c;
+                               size_t n;
+
+                               irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
+
+                               for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
+                                       free_entity(cr_opt[c].ent);
+                               }
+                       }
+               }
+       }
+
+       obstack_free(&env.obst, NULL);
 }
 
-/**
- * Returns non-zero if the given type is a method
- * type that must be lowered.
- *
- * @param lp  lowering parameters
- * @param tp  The type.
- */
-static int must_be_lowered(const lower_params_t *lp, ir_type *tp) {
-  int i, n_ress;
-  ir_type *res_tp;
-
-  if (is_Method_type(tp)) {
-    if (lp->flags & LF_COMPOUND_RETURN) {
-      /* check for compound returns */
-      n_ress = get_method_n_ress(tp);
-      for (i = 0; i < n_ress; ++i) {
-        res_tp = get_method_res_type(tp, i);
-
-        if (is_compound_type(res_tp))
-          return 1;
-      }
-    }
-  }
-  return 0;
-}
-
-/**
- * type-walker: lower all method types of entities
- * and points-to types.
- */
-static void lower_method_types(type_or_ent *tore, void *env)
+static void lower_method_types(type_or_ent tore, void *env)
 {
-  const lower_params_t *lp = env;
-  ir_type *tp;
-
-  /* fix method entities */
-  if (is_entity(tore)) {
-    ir_entity *ent = (ir_entity *)tore;
-    tp = get_entity_type(ent);
-
-    if (must_be_lowered(lp, tp)) {
-      tp = create_modified_mtd_type(lp, tp);
-      set_entity_type(ent, tp);
-    }
-  }
-  else {
-    tp = (ir_type *)tore;
-
-    /* fix pointer to methods */
-    if (is_Pointer_type(tp)) {
-      ir_type *etp = get_pointer_points_to_type(tp);
-      if (must_be_lowered(lp, etp)) {
-        etp = create_modified_mtd_type(lp, etp);
-        set_pointer_points_to_type(tp, etp);
-      }
-    }
-  }
+       const compound_call_lowering_flags *flags
+               = (const compound_call_lowering_flags*)env;
+
+       /* fix method entities */
+       if (is_entity(tore.ent)) {
+               ir_entity *ent     = tore.ent;
+               ir_type   *tp      = get_entity_type(ent);
+               ir_type   *lowered = lower_mtp(*flags, tp);
+               set_entity_type(ent, lowered);
+       } else {
+               ir_type *tp = tore.typ;
+
+               /* fix pointer to methods */
+               if (is_Pointer_type(tp)) {
+                       ir_type *points_to         = get_pointer_points_to_type(tp);
+                       ir_type *lowered_points_to = lower_mtp(*flags, points_to);
+                       set_pointer_points_to_type(tp, lowered_points_to);
+               }
+       }
 }
 
-/*
- * Lower calls with compound parameters and return types.
- * This function does the following transformations:
- *
- * - Adds a new (hidden) pointer parameter for
- *   any return compound type.
- *
- * - Use of the hidden parameters in the function code.
- *
- * - Change all calls to functions with compound return
- *   by providing space for the hidden parameter on the callers
- *   stack.
- *
- * - Replace a possible block copy after the function call.
- */
-void lower_calls_with_compounds(const lower_params_t *params)
+void lower_calls_with_compounds(compound_call_lowering_flags flags)
 {
-  int i;
-  ir_graph *irg;
-  lower_params_t param = *params;
-
-  if (param.find_pointer_type == NULL) {
-    param.find_pointer_type = def_find_pointer_type;
-    type_map = pmap_create_ex(8);
-  }
-  else
-    type_map = NULL;
-
-  /* first step: Transform all graphs */
-  for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
-    irg = get_irp_irg(i);
+       size_t i, n;
 
-    if (irg == get_const_code_irg())
-      continue;
+       pointer_types = pmap_create();
+       lowered_mtps = pmap_create();
 
-    transform_irg(&param, irg);
-  }
+       /* first step: Transform all graphs */
+       for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
+               ir_graph *irg = get_irp_irg(i);
+               transform_irg(flags, irg);
+       }
 
-  /* second step: Lower all method types of visible entities */
-  type_walk(NULL, lower_method_types, &param);
+       /* second step: Lower all method types of visible entities */
+       type_walk(NULL, lower_method_types, &flags);
 
-  if (type_map)
-    pmap_destroy(type_map);
+       pmap_destroy(lowered_mtps);
+       pmap_destroy(pointer_types);
 }