Commit 9e5fa4a2 authored by Michael Beck's avatar Michael Beck
Browse files

First implementation of lowering for calls with compound return values

[r7388]
parent 0f6a4343
/*
* 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 Universitt 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.
*/
}
/*
* Project: libFIRM
* File name: ir/lower/lower_calls.h
* 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.
*/
/**
* @file lower_calls.h
*
* Lowering of Calls with compound return types.
*
* @author Michael Beck
*/
#ifndef _LOWER_CALLS_H_
#define _LOWER_CALLS_H_
/**
* A type telling where to add hidden parameters.
*/
typedef enum add_hidden_params {
ADD_HIDDEN_ALWAYS_IN_FRONT = 0, /**< always add hidden parameters in front (default). */
ADD_HIDDEN_ALWAYS_LAST = 1, /**< always add hidden parameters last, did not work for variadic functions. */
ADD_HIDDEN_SMART = 2, /**< add hidden parameters last for non-variadic and first for variadic functions. */
} add_hidden;
typedef struct {
int def_ptr_alignment; /**< default alignment for data pointer */
add_hidden hidden_params; /**< where to add hidden params. */
/** a function returning a pointer type for a given type */
ir_type *(*find_pointer_type)(ir_type *e_type, ir_mode *mode, int alignment);
} lower_params_t;
/**
* 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);
#endif /* _LOWER_CALLS_H_ */
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