fix lower_calls sometimes not lowering method type
[libfirm] / ir / lower / lower_calls.c
index 31da624..f51ef6a 100644 (file)
@@ -1,27 +1,12 @@
 /*
- * Copyright (C) 1995-2011 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
  */
 #include "config.h"
 
 #include "array_t.h"
 #include "pmap.h"
 #include "error.h"
+#include "util.h"
 
 static pmap *pointer_types;
 static pmap *lowered_mtps;
 
+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 *get_pointer_type(ir_type *dest_type)
 {
-       ir_type *res = (ir_type*)pmap_get(pointer_types, dest_type);
+       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);
@@ -60,6 +51,45 @@ static ir_type *get_pointer_type(ir_type *dest_type)
        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.
@@ -75,27 +105,38 @@ static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
        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 = (ir_type*)pmap_get(lowered_mtps, 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_ress = get_method_n_ress(mtp);
+       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 (is_compound_type(res_tp)) {
+               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;
 
-       n_params  = get_method_n_params(mtp);
        results   = ALLOCANZ(ir_type*, n_ress);
        params    = ALLOCANZ(ir_type*, n_params + n_ress);
        nn_ress   = 0;
@@ -105,7 +146,7 @@ static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
        for (i = 0; i < n_ress; ++i) {
                ir_type *res_tp = get_method_res_type(mtp, i);
 
-               if (is_compound_type(res_tp)) {
+               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);
@@ -119,7 +160,12 @@ static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
        }
        /* copy over parameter types */
        for (i = 0; i < n_params; ++i) {
-               params[nn_params++] = get_method_param_type(mtp, 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);
@@ -135,10 +181,20 @@ static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
 
        set_method_variadicity(lowered, get_method_variadicity(mtp));
 
-       /* associate the lowered type with the original one for easier access */
-       set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
+       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);
 
-       set_lowered_type(mtp, lowered);
+       /* associate the lowered type with the original one for easier access */
+       set_higher_type(lowered, mtp);
        pmap_insert(lowered_mtps, mtp, lowered);
 
        return lowered;
@@ -152,6 +208,8 @@ 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. */
+       bool      has_compound_ret   : 1;
+       bool      has_compound_param : 1;
 };
 
 /**
@@ -161,12 +219,10 @@ 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. */
-       pmap                 *dummy_map;       /**< A map for finding the dummy arguments. */
        compound_call_lowering_flags flags;
        ir_type              *lowered_mtp;     /**< The lowered method type of the current irg if any. */
-       ir_type              *value_params;    /**< The value params type if any. */
-       unsigned             only_local_mem:1; /**< Set if only local memory access was found. */
-       unsigned             changed:1;        /**< Set if the current graph was changed. */
+       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;
 
 /**
@@ -177,7 +233,7 @@ 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)
+static cl_entry *get_call_entry(ir_node *call, wlk_env *env)
 {
        cl_entry *res = (cl_entry*)get_irn_link(call);
        if (res == NULL) {
@@ -238,7 +294,7 @@ static void check_ptr(ir_node *ptr, wlk_env *env)
        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 = 0;
+               env->only_local_mem = false;
        }
 }
 
@@ -254,9 +310,9 @@ static bool is_self_recursive_Call(const ir_node *call)
                const ir_entity *ent = get_SymConst_entity(callee);
                const ir_graph  *irg = get_entity_irg(ent);
                if (irg == get_irn_irg(call))
-                       return 1;
+                       return true;
        }
-       return 0;
+       return false;
 }
 
 /**
@@ -268,24 +324,9 @@ static bool is_self_recursive_Call(const ir_node *call)
 static void fix_args_and_collect_calls(ir_node *n, void *ctx)
 {
        wlk_env *env = (wlk_env*)ctx;
-       ir_type *ctp;
        ir_node *ptr;
 
        switch (get_irn_opcode(n)) {
-       case iro_Sel:
-               if (env->lowered_mtp != NULL && env->value_params != NULL) {
-                       ir_entity *ent = get_Sel_entity(n);
-
-                       if (get_entity_owner(ent) == env->value_params) {
-                               size_t pos = get_struct_member_index(env->value_params, ent) + env->arg_shift;
-                               ir_entity *new_ent;
-
-                               new_ent = get_method_value_param_ent(env->lowered_mtp, pos);
-                               set_entity_ident(new_ent, get_entity_ident(ent));
-                               set_Sel_entity(n, new_ent);
-                       }
-               }
-               break;
        case iro_Load:
        case iro_Store:
                if (env->only_local_mem) {
@@ -302,27 +343,38 @@ static void fix_args_and_collect_calls(ir_node *n, void *ctx)
                        if (pred == get_irg_args(irg)) {
                                long pnr = get_Proj_proj(n);
                                set_Proj_proj(n, pnr + env->arg_shift);
-                               env->changed = 1;
+                               env->changed = true;
                        }
                }
                break;
        case iro_Call: {
-               size_t i;
-               size_t n_res;
+               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 = 0;
+                       env->only_local_mem = false;
                }
 
-               ctp = get_Call_type(n);
                /* check for compound returns */
-               for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
-                       if (is_compound_type(get_method_res_type(ctp, i))) {
+               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.
                                 */
-                               (void)get_Call_entry(n, env);
+                               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;
                        }
                }
@@ -341,10 +393,10 @@ static void fix_args_and_collect_calls(ir_node *n, void *ctx)
                        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)))) {
+                                       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);
+                                               cl_entry *e = get_call_entry(call, env);
                                                set_irn_link(n, e->copyb);
                                                e->copyb = n;
                                        }
@@ -353,6 +405,28 @@ static void fix_args_and_collect_calls(ir_node *n, void *ctx)
                }
                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;
@@ -410,53 +484,32 @@ static void do_copy_return_opt(ir_node *n, void *ctx)
 
 /**
  * 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;
+       ir_type   *ft       = get_irg_frame_type(irg);
+       ident     *dummy_id = id_unique("dummy.%u");
+       ir_entity *ent      = new_entity(ft, dummy_id, tp);
 
-       /* use a map the check if we already create such an entity */
-       e = pmap_find(env->dummy_map, tp);
-       if (e) {
-               ent = (ir_entity*)e->value;
-       } else {
-               ir_type *ft = get_irg_frame_type(irg);
-               ident   *dummy_id = id_unique("dummy.%u");
-               ent = new_entity(ft, dummy_id, tp);
-               pmap_insert(env->dummy_map, tp, ent);
-
-               if (get_type_state(ft) == layout_fixed) {
-                       /* Fix the layout again */
-                       panic("Fixed layout not implemented");
-               }
+       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, size_t n_com, ir_node **ins,
-                             cl_entry *entry, wlk_env *env)
+                             cl_entry *entry, ir_type *ctp)
 {
-       ir_node *p, *n, *mem, *blk;
+       ir_node *p, *n;
        size_t n_args;
 
        n_args = 0;
@@ -465,77 +518,141 @@ static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
                size_t   idx = get_Proj_proj(src);
                n = (ir_node*)get_irn_link(p);
 
-               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+1);
-               set_Tuple_pred(p, pn_CopyB_M,         mem);
-               set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
-               set_Tuple_pred(p, pn_CopyB_X_except,  new_r_Bad(irg, mode_X));
-               ++n_args;
+               /* 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) {
-               ir_type *ctp = get_Call_type(entry->call);
-               size_t   i;
-               size_t   j;
-
-               if (is_lowered_type(ctp))
-                       ctp = get_associated_type(ctp);
+               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 (is_compound_type(rtp)) {
+                       if (needs_lowering(rtp)) {
                                if (ins[j] == NULL)
-                                       ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
+                                       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)
+static void fix_compound_ret(cl_entry *entry, ir_type *ctp)
 {
-       cl_entry *p;
-       ir_node *call, **new_in;
-       ir_type *ctp, *lowered_mtp;
-       size_t i, n_res, 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 = lower_mtp(env->flags, ctp);
-               set_Call_type(call, lowered_mtp);
+       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;
 
-               n_params = get_Call_n_params(call);
+       /* 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;
+}
 
-               n_com = 0;
-               for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
-                       if (is_compound_type(get_method_res_type(ctp, i)))
-                               ++n_com;
+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);
                }
-               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));
-               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);
-               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);
        }
 }
 
@@ -549,56 +666,68 @@ static void fix_call_list(ir_graph *irg, wlk_env *env)
  */
 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;
-       size_t     i, j, k, n_ress = 0, n_ret_com = 0;
-       size_t     n_cr_opt;
-       ir_node    **new_in, *ret, *endbl, *bl, *mem, *copy;
-       cr_pair    *cr_opt;
-       wlk_env    env;
-
-       mtp = get_entity_type(ent);
+       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 */
-       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))
+       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);
 
-               /* This graph has a compound argument. Create a new type */
-               lowered_mtp = lower_mtp(flags, mtp);
-               set_entity_type(ent, lowered_mtp);
-
                /* hidden arguments are added first */
-               env.arg_shift    = n_ret_com;
+               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.dummy_map      = pmap_create_ex(8);
        env.flags          = flags;
        env.lowered_mtp    = lowered_mtp;
-       env.value_params   = get_method_value_param_type(mtp);
-       env.only_local_mem = 1;
-       env.changed        = 0;
+       env.only_local_mem = true;
+       env.changed        = false;
 
        /* scan the code, fix argument numbers and collect calls. */
-       irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
+       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) {
-               fix_call_list(irg, &env);
-               env.changed = 1;
+       if (env.cl_list != NULL) {
+               fix_calls(&env);
+               env.changed = true;
        }
 
        if (n_ret_com) {
@@ -621,7 +750,7 @@ static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
                        /*
                         * Now fix the Return node of the current graph.
                         */
-                       env.changed = 1;
+                       env.changed = true;
 
                        /*
                         * STEP 2: fix it. For all compound return values add a CopyB,
@@ -639,7 +768,7 @@ static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
                                ir_node *pred = get_Return_res(ret, i);
                                tp = get_method_res_type(mtp, i);
 
-                               if (is_compound_type(tp)) {
+                               if (needs_lowering(tp)) {
                                        ir_node *arg = get_irg_args(irg);
                                        arg = new_r_Proj(arg, mode_P_data, k);
                                        ++k;
@@ -697,7 +826,6 @@ static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
                }
        }
 
-       pmap_destroy(env.dummy_map);
        obstack_free(&env.obst, NULL);
 }