2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @author Sebastian Hack, Matthias Braun
25 * Handling of the stack frame. It is composed of three types:
26 * 1) The type of the arguments which are pushed on the stack.
27 * 2) The "between type" which consists of stuff the call of the
28 * function pushes on the stack (like the return address and
29 * the old base pointer for ia32).
30 * 3) The Firm frame type which consists of all local variables
39 #include "bessaconstr.h"
46 int be_get_stack_entity_offset(be_stack_layout_t *frame, ir_entity *ent,
49 ir_type *t = get_entity_owner(ent);
50 int ofs = get_entity_offset(ent);
54 /* Find the type the entity is contained in. */
55 for (index = 0; index < N_FRAME_TYPES; ++index) {
56 if (frame->order[index] == t)
58 /* Add the size of all the types below the one of the entity to the entity's offset */
59 ofs += get_type_size_bytes(frame->order[index]);
62 /* correct the offset by the initial position of the frame pointer */
63 ofs -= frame->initial_offset;
65 /* correct the offset with the current bias. */
72 * Retrieve the entity with given offset from a frame type.
74 static ir_entity *search_ent_with_offset(ir_type *t, int offset)
78 for (i = 0, n = get_compound_n_members(t); i < n; ++i) {
79 ir_entity *ent = get_compound_member(t, i);
80 if (get_entity_offset(ent) == offset)
87 static int stack_frame_compute_initial_offset(be_stack_layout_t *frame)
89 ir_type *base = frame->between_type;
90 ir_entity *ent = search_ent_with_offset(base, 0);
93 frame->initial_offset = get_type_size_bytes(frame->frame_type);
95 frame->initial_offset = be_get_stack_entity_offset(frame, ent, 0);
98 return frame->initial_offset;
102 * Walker: finally lower all Sels of outer frame or parameter
105 static void lower_outer_frame_sels(ir_node *sel, void *ctx)
110 be_stack_layout_t *layout;
117 ent = get_Sel_entity(sel);
118 owner = get_entity_owner(ent);
119 ptr = get_Sel_ptr(sel);
120 irg = get_irn_irg(sel);
121 layout = be_get_irg_stack_layout(irg);
123 if (owner == layout->frame_type || owner == layout->arg_type) {
124 /* found access to outer frame or arguments */
125 int offset = be_get_stack_entity_offset(layout, ent, 0);
128 ir_node *bl = get_nodes_block(sel);
129 dbg_info *dbgi = get_irn_dbg_info(sel);
130 ir_mode *mode = get_irn_mode(sel);
131 ir_mode *mode_UInt = get_reference_mode_unsigned_eq(mode);
132 ir_node *cnst = new_r_Const_long(current_ir_graph, mode_UInt, offset);
134 ptr = new_rd_Add(dbgi, bl, ptr, cnst, mode);
141 * A helper struct for the bias walker.
143 typedef struct bias_walk {
144 int start_block_bias; /**< The bias at the end of the start block. */
146 ir_node *start_block; /**< The start block of the current graph. */
150 * Fix all stack accessing operations in the block bl.
152 * @param bl the block to process
153 * @param real_bias the bias value
155 * @return the bias at the end of this block
157 static int process_stack_bias(ir_node *bl, int real_bias)
159 int wanted_bias = real_bias;
160 ir_graph *irg = get_Block_irg(bl);
161 be_stack_layout_t *layout = be_get_irg_stack_layout(irg);
162 bool sp_relative = layout->sp_relative;
163 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
166 sched_foreach(bl, irn) {
170 Check, if the node relates to an entity on the stack frame.
171 If so, set the true offset (including the bias) for that
174 ir_entity *ent = arch_get_frame_entity(irn);
176 int bias = sp_relative ? real_bias : 0;
177 int offset = be_get_stack_entity_offset(layout, ent, bias);
178 arch_set_frame_offset(irn, offset);
182 * If the node modifies the stack pointer by a constant offset,
183 * record that in the bias.
185 if (be_is_IncSP(irn)) {
186 ofs = be_get_IncSP_offset(irn);
187 /* fill in real stack frame size */
188 if (be_get_IncSP_align(irn)) {
189 /* patch IncSP to produce an aligned stack pointer */
190 ir_type *between_type = layout->between_type;
191 int between_size = get_type_size_bytes(between_type);
192 int alignment = 1 << arch_env->stack_alignment;
193 int delta = (real_bias + ofs + between_size) & (alignment - 1);
196 be_set_IncSP_offset(irn, ofs + alignment - delta);
197 real_bias += alignment - delta;
200 /* adjust so real_bias corresponds with wanted_bias */
201 int delta = wanted_bias - real_bias;
204 be_set_IncSP_offset(irn, ofs + delta);
211 ofs = arch_get_sp_bias(irn);
212 if (ofs == SP_BIAS_RESET) {
222 assert(real_bias == wanted_bias);
227 * Block-Walker: fix all stack offsets for all blocks
228 * except the start block
230 static void stack_bias_walker(ir_node *bl, void *data)
232 bias_walk *bw = (bias_walk*)data;
233 if (bl != bw->start_block) {
234 process_stack_bias(bl, bw->start_block_bias);
238 void be_abi_fix_stack_bias(ir_graph *irg)
240 be_stack_layout_t *stack_layout = be_get_irg_stack_layout(irg);
245 stack_frame_compute_initial_offset(stack_layout);
247 /* Determine the stack bias at the end of the start block. */
248 bw.start_block_bias = process_stack_bias(get_irg_start_block(irg),
249 stack_layout->initial_bias);
250 bw.between_size = get_type_size_bytes(stack_layout->between_type);
252 /* fix the bias is all other blocks */
253 bw.start_block = get_irg_start_block(irg);
254 irg_block_walk_graph(irg, stack_bias_walker, NULL, &bw);
256 /* fix now inner functions: these still have Sel node to outer
257 frame and parameter entities */
258 frame_tp = get_irg_frame_type(irg);
259 for (i = get_class_n_members(frame_tp) - 1; i >= 0; --i) {
260 ir_entity *ent = get_class_member(frame_tp, i);
261 ir_graph *irg = get_entity_irg(ent);
264 irg_walk_graph(irg, NULL, lower_outer_frame_sels, NULL);
269 typedef struct fix_stack_walker_env_t {
271 } fix_stack_walker_env_t;
274 * Walker. Collect all stack modifying nodes.
276 static void collect_stack_nodes_walker(ir_node *node, void *data)
278 ir_node *insn = node;
279 fix_stack_walker_env_t *env = (fix_stack_walker_env_t*)data;
280 const arch_register_req_t *req;
283 insn = get_Proj_pred(node);
286 if (arch_irn_get_n_outs(insn) == 0)
288 if (get_irn_mode(node) == mode_T)
291 req = arch_get_register_req_out(node);
292 if (! (req->type & arch_register_req_type_produces_sp))
295 ARR_APP1(ir_node*, env->sp_nodes, node);
298 void be_abi_fix_stack_nodes(ir_graph *irg)
300 be_lv_t *lv = be_get_irg_liveness(irg);
301 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
302 be_irg_t *birg = be_birg_from_irg(irg);
303 const arch_register_req_t *sp_req = birg->sp_req;
304 const arch_register_t *sp = arch_env->sp;
305 be_ssa_construction_env_t senv;
308 fix_stack_walker_env_t walker_env;
310 if (sp_req == NULL) {
311 struct obstack *obst = be_get_be_obst(irg);
312 arch_register_req_t *new_sp_req;
313 unsigned *limited_bitset;
315 new_sp_req = OALLOCZ(obst, arch_register_req_t);
316 new_sp_req->type = arch_register_req_type_limited
317 | arch_register_req_type_produces_sp;
318 new_sp_req->cls = arch_register_get_class(arch_env->sp);
319 new_sp_req->width = 1;
321 limited_bitset = rbitset_obstack_alloc(obst, new_sp_req->cls->n_regs);
322 rbitset_set(limited_bitset, arch_register_get_index(sp));
323 new_sp_req->limited = limited_bitset;
325 if (!rbitset_is_set(birg->allocatable_regs, sp->global_index)) {
326 new_sp_req->type |= arch_register_req_type_ignore;
330 birg->sp_req = new_sp_req;
333 walker_env.sp_nodes = NEW_ARR_F(ir_node*, 0);
335 irg_walk_graph(irg, collect_stack_nodes_walker, NULL, &walker_env);
337 /* nothing to be done if we didn't find any node, in fact we mustn't
338 * continue, as for endless loops incsp might have had no users and is bad
341 len = ARR_LEN(walker_env.sp_nodes);
343 DEL_ARR_F(walker_env.sp_nodes);
347 be_ssa_construction_init(&senv, irg);
348 be_ssa_construction_add_copies(&senv, walker_env.sp_nodes,
349 ARR_LEN(walker_env.sp_nodes));
350 be_ssa_construction_fix_users_array(&senv, walker_env.sp_nodes,
351 ARR_LEN(walker_env.sp_nodes));
354 len = ARR_LEN(walker_env.sp_nodes);
355 for (i = 0; i < len; ++i) {
356 be_liveness_update(lv, walker_env.sp_nodes[i]);
358 be_ssa_construction_update_liveness_phis(&senv, lv);
361 phis = be_ssa_construction_get_new_phis(&senv);
363 /* set register requirements for stack phis */
365 for (i = 0; i < len; ++i) {
366 ir_node *phi = phis[i];
367 be_set_phi_reg_req(phi, sp_req);
368 arch_set_irn_register(phi, arch_env->sp);
370 be_ssa_construction_destroy(&senv);
371 DEL_ARR_F(walker_env.sp_nodes);
373 /* when doing code with frame-pointers then often the last incsp-nodes are
374 * not used anymore because we copy the framepointer to the stack pointer
375 * when leaving the function. Though the last incsp is often kept (because
376 * you often don't know which incsp is the last one and fixstack should find
377 * them all). Remove unnecessary keeps and IncSP nodes */
379 ir_node *end = get_irg_end(irg);
380 int arity = get_irn_arity(end);
382 for (i = arity-1; i >= 0; --i) {
383 ir_node *in = get_irn_n(end, i);
384 if (!be_is_IncSP(in)) {
388 remove_End_keepalive(end, in);
389 if (get_irn_n_edges(in) == 0) {