--- /dev/null
+/*
+ * Project: libFIRM
+ * File name: ir/lower/lower_calls.c
+ * Purpose: lowering of Calls with compound parameters
+ * Author: Michael Beck
+ * Created:
+ * CVS-ID: $Id$
+ * Copyright: (c) 1998-2005 Universität Karlsruhe
+ * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
+#ifdef HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+
+#include "irprog_t.h"
+#include "irnode_t.h"
+#include "type_t.h"
+#include "irmode_t.h"
+#include "ircons.h"
+#include "irgmod.h"
+#include "irgwalk.h"
+#include "lower_calls.h"
+#include "return.h"
+#include "array.h"
+
+/**
+ * Creates a new lowered type for a method type with compound
+ * arguments. The new type is associated to the old one and returned.
+ */
+static ir_type *create_modified_mtd_type(const lower_params_t *lp, ir_type *mtp)
+{
+ ir_type *lowered;
+ ir_type **params, **results, *res_tp;
+ int n_ress, n_params, nn_ress, nn_params, i, first_variadic;
+ ident *id;
+ add_hidden hidden_params;
+ 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))
+ params[nn_params++] = lp->find_pointer_type(res_tp, get_modeP_data(), lp->def_ptr_alignment);
+ 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 */
+ set_lowered_type(mtp, lowered);
+
+ return lowered;
+}
+
+/**
+ * Walker environment for fix_value_res_access().
+ */
+typedef struct _wlk_env_t {
+ int arg_shift; /**< argument index shift for parameters. */
+ int first_hidden; /**< index of the first hidden argument. */
+} wlk_env;
+
+/**
+ * Post walker: shift all parameter indeces and remove
+ * Sel(Proj(P_frame_base())
+ */
+static void fix_value_res_access(ir_node *n, void *ctx) {
+ wlk_env *env = ctx;
+
+ if (env->arg_shift > 0 && is_Proj(n)) {
+ 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);
+ }
+ }
+}
+
+/**
+ * returns non-zero if adr is a compound address
+ * of a frame-type entity
+ *
+ * @param ft the frame type
+ * @param adr the node
+ */
+static int is_compound_address(ir_type *ft, ir_node *adr)
+{
+ 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;
+}
+
+/** A pair for the copy-return-optimization */
+typedef struct cr_pair {
+ 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 array to be 1 (C, C++),
+ * so ignore the linear search.
+ */
+static void do_copy_return_opt(ir_node *n, void *ctx) {
+ cr_pair *arr = ctx;
+ int i;
+
+ if (is_Sel(n)) {
+ 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;
+ }
+ }
+ }
+}
+
+/**
+ * Transform all graphs with compound parameter return:
+ * Remove the return and use the hidden parameter instead.
+ *
+ * @param irg the graph to transform
+ */
+static void transform_irg(const lower_params_t *lp, ir_graph *irg)
+{
+ entity *ent = get_irg_entity(irg);
+ ir_type *mtp, *lowered_mtp, *res_tp, *ft;
+ int i, j, k, n_ress, n_com, 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);
+ n_ress = get_method_n_ress(mtp);
+ for (n_com = i = 0; i < n_ress; ++i) {
+ res_tp = get_method_res_type(mtp, i);
+
+ if (is_compound_type(res_tp))
+ ++n_com;
+ }
+ if (! n_com)
+ return;
+
+ /* 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_com;
+ env.first_hidden = 0;
+ }
+ else {
+ /* hidden arguments are added last */
+ env.arg_shift = 0;
+ env.first_hidden = get_method_n_params(mtp);
+ }
+
+ if (env.arg_shift > 0) {
+ /* scan the code and argument numbers. */
+ irg_walk_graph(irg, NULL, fix_value_res_access, &env);
+ }
+
+ /*
+ * Now fix the return.
+ */
+
+ /* STEP 1: find the return */
+ 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 value add a CopyB,
+ * all others are copied.
+ */
+ NEW_ARR_A(ir_node *, new_in, n_ress - n_com + 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_com);
+ n_cr_opt = 0;
+ for (j = 1, i = k = 0; i < n_ress; ++i) {
+ ir_node *pred = get_Return_res(ret, i);
+ res_tp = get_method_res_type(mtp, i);
+
+ if (is_compound_type(res_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 {
+ /* we cannot do copy-return optimization */
+ copy = new_r_CopyB(
+ irg, bl,
+ mem,
+ arg,
+ pred,
+ res_tp
+ );
+ mem = new_r_Proj(irg, bl, copy, mode_M, pn_CopyB_M_regular);
+ }
+ }
+ else {
+ new_in[j] = pred;
+ ++j;
+ }
+ }
+ 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);
+ }
+ }
+
+ dump_ir_block_graph(irg, "-lc");
+}
+
+/*
+ * Lower calls with compound 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_compound_ret_calls(const lower_params_t *params)
+{
+ int i;
+ ir_graph *irg;
+
+ /* second step: Transform all graphs */
+ for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
+ irg = get_irp_irg(i);
+
+ if (irg == get_const_code_irg())
+ continue;
+
+ transform_irg(params, irg);
+ }
+
+ /*
+ * Last step: transform any other method types.
+ */
+}
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