2 * Copyright (C) 1995-2007 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 * File name: ir/ir/irflag.h
23 * Purpose: Flags to control optimizations.
24 * Author: Christian Schaefer, Goetz Lindenmaier
25 * Modified by: Michael Beck
28 * Copyright: (c) 1999-2003 Universität Karlsruhe
34 * Flags to customize the behavior of libfirm.
36 * @author Christian Schaefer
38 * There are the following groups of flags:
39 * 1. Optimization flags.
40 * a) There is a flag, 'optimize' to turn on/off all optimizations.
41 * b) There are flags for each individual optimization. Some flags turns
42 * transformations in several algorithms on/off.
43 * 2. Normalization flags.
44 * These flags steer transformations of the ir that improve it, as removing
45 * dump Phi nodes (one predecessor, all predecessors are equal ...), Ids, Tuples ...
47 * a) Flags to steer the level of the information.
48 * b) Flags to steer in which phase information should be dumped.
49 * 4. Verification flag
50 * This one controls the behavior of node and type verifications
52 #ifndef _FIRM_IR_IRFLAG_H_
53 #define _FIRM_IR_IRFLAG_H_
55 #include "firm_types.h"
58 * A container type to load/restore all optimizations
60 typedef unsigned optimization_state_t;
63 * This function enables/disables optimizations globally.
65 * If optimize == 0 no optimizations are performed at all.
66 * Default: optimize == 1.
68 void set_optimize (int value);
69 int get_optimize(void);
71 /** This function enables/disables output of information about phases and
72 * controls the verbosity level.
74 * 0: no output at all.
75 * 1: very short output
76 * >>1: very verbose output.
78 void set_firm_verbosity (int value);
79 int get_firm_verbosity (void);
81 /** Enables/Disables constant folding optimization.
83 * If opt_constant_folding == 1 perform
84 * - constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
85 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
86 * - simplification of tests ( !(a < b) ==> (a >= b))
87 * Default: opt_constant_folding == 1.
89 void set_opt_constant_folding (int value);
91 /** Enables/Disables loop unrolling.
93 * If opt_loop_unrolling == 1 perform loop_unrolling.
94 * See loop_unrolling.h.
96 * Default: opt_loop_unrolling = 1;
98 void set_opt_loop_unrolling (int value);
100 /** Enables/Disables output of information about loop unrolling.
102 void set_opt_loop_unrolling_verbose (int value);
104 /** Enables/Disables removal of redundant Loads and Stores.
106 * - Remove Store that overwrites a just stored value (WAW).
107 * - Remove Store if it stores a value just loaded (WAR with the same value).
108 * - Remove Load that loads a value just saved (RAW with the same value).
109 * - remove Load that loads a value already loaded (RAR)
110 * - replace Load of constant values with constants (RC)
112 void set_opt_redundant_loadstore(int value);
114 /** Enables/Disables common subexpression elimination.
116 * If opt_cse == 1 perform common subexpression elimination.
117 * Default: opt_cse == 1.
119 void set_opt_cse (int value);
121 /** Returns constant folding optimization setting. */
122 int get_opt_cse(void);
124 /** Enables/Disables global constant subexpression elimination.
126 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
127 * constant subexpression elimination for floating nodes. Intra
128 * procedure cse gets the graph into state "floating". It is necessary
129 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
130 * right after a call to local_optimize with global cse turned on.
131 * Default: opt_global_cse == 0.
133 void set_opt_global_cse (int value);
135 /** Enables/Disables strength reduction.
137 * If opt_strength_red == 1 perform strength reduction.
140 * Default: opt_strength_red = 1;
142 void set_opt_strength_red (int value);
144 /** Enables/Disables output of information about strength reduction.
146 void set_opt_strength_red_verbose (int value);
148 /** Enables/Disables unreachable code elimination.
150 * If set, evaluate conditions of conditional branch and replace the
151 * branch with a Jmp/Bad Tuple.
153 * If opt_unreachable_code == 1 replace nodes (except Block,
154 * Phi and Tuple) with a Bad predecessor by the Bad node.
155 * Default: opt_unreachable_code == 1.
157 void set_opt_unreachable_code(int value);
159 /** Enables/Disables control flow optimizations.
161 * Performs Straightening, if simplifications and loop simplifications.
162 * Sets all separate control flow flags (control_flow_straightening,
163 * weak_simplification, strong_simplification and critical_edges).
165 void set_opt_control_flow(int value);
167 /** Enables/Disables Straightening. */
168 void set_opt_control_flow_straightening(int value);
170 /** Enables/Disables if simplifications in local optimizations. */
171 void set_opt_control_flow_weak_simplification(int value);
173 /** Enables/Disables strong if and loop simplification (in optimize_cf). */
174 void set_opt_control_flow_strong_simplification(int value);
176 /** Enables/Disables reassociation.
178 * If opt_reassociation == 1 reassociation is performed.
179 * Default: opt_reassociation == 1.
181 void set_opt_reassociation(int value);
183 /** Enables/Disables dead node elimination.
185 * If opt_dead_node_elimination == 1 deallocate all dead nodes
186 * by copying the firm graph.
187 * Default: opt_dead_node_elimination == 1. */
188 void set_opt_dead_node_elimination (int value);
190 /** Enables/Disables dead method elimination.
192 * If opt_dead_method_elimination == 1 methods never called are
194 * Default: opt_dead_method_elimination == 1.
196 void set_opt_dead_method_elimination (int value);
197 void set_opt_dead_method_elimination_verbose (int value);
199 /** Enable/Disables method inlining.
201 * If opt_inline == 1 the inlining transformation is performed.
203 void set_opt_inline (int value);
205 /** Enable/Disable optimization of dynamic method dispatch.
207 * This flag enables/disables the optimization of dynamic method dispatch.
208 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
209 * the address of a function.
211 void set_opt_dyn_meth_dispatch (int value);
212 int get_opt_dyn_meth_dispatch (void);
214 /** Enable/Disable type optimization of cast nodes.
216 * Controls the optimizations in tropt.h. Default: on.
218 void set_opt_optimize_class_casts (int value);
219 void set_opt_optimize_class_casts_verbose (int value);
221 /** Restricts the behavior of cast optimization.
223 * If set, downcast are not optimized if they might be
224 * illegal as in (Super)(Sub) (new Super()). Default:
225 * 0 == not suppressed.
227 void set_opt_suppress_downcast_optimization(int value);
228 int get_opt_suppress_downcast_optimization(void);
230 /** Enable/Disable optimization of tail-recursion calls.
232 * This flag enables/disables the optimization tail-recursion call.
233 * If the flag is turned on tail-recursion calls are optimized into loops.
235 void set_opt_tail_recursion(int value);
236 void set_opt_tail_recursion_verbose(int value);
238 /** Enable/Disable floating of fragile ops.
240 * This flags enables/disables the floating of fragile operations.
241 * If this flag is on, fragile operations which are known to NOT raise
242 * an exception can be place to other basic blocks.
243 * Otherwise they remain in the block they were created.
245 void set_opt_fragile_ops(int value);
248 * Enable/Disable if conversion.
250 * If conversion tries to turn Conds into Mux nodes to eliminate
253 void set_opt_if_conversion(int value);
256 * Enable/Disable function call optimization.
258 * Function call optimization detects const and pure functions and
259 * allows the CSE of Call nodes. A const function is one that
260 * do only evaluate it's parameters and did not read or write memory
261 * to compute its results. Pure functions are allowed to read global memory.
263 void set_opt_function_call(int value);
266 * Enable/Disable Confirm node removal during local optimization.
268 void set_opt_remove_confirm(int value);
271 * Enable/Disable scalar replacement optimization.
273 void set_opt_scalar_replacement(int value);
274 void set_opt_scalar_replacement_verbose(int value);
277 * Enable/Disable Null exception in Load and Store nodes only.
279 * If enabled, only Null pointer exception can occur at Load and
280 * store nodes. If it can be proved that the address input of these
281 * nodes is non-null, the exception edge can safely be removed.
282 * If disabled, other exceptions (like unaligned access, read-only memory,
285 * This flag is enabled by default.
287 void set_opt_ldst_only_null_ptr_exceptions(int value);
290 * Enable/Disable Selection based Null pointer check elimination.
292 * In languages, where all addresses are always Sel nodes, Null
293 * pointers can only occur as input to Sel nodes.
294 * If Null pointers are the only source for exceptions in Load and
295 * Store nodes (as typical in high level languages), we can eliminate
296 * exception edges from Load and Store when can prove that the Sel
297 * nodes representing the Load/Store address have non-null inputs.
298 * Enabling this flag enables this elimination.
300 * Enabling this flag is meaningless if ldst_non_null_exceptions is
303 * This flags should be set for Java style languages.
305 void set_opt_sel_based_null_check_elim(int value);
308 * Enable/Disable Automatic construction of Sync nodes during
311 * If this flags is set, sequential non-volatile Loads are automatically
312 * rearranged so that they can be executed in parallel by creating Sync nodes.
314 * This flags should be set for Java style languages.
316 void set_opt_auto_create_sync(int value);
318 /** Enable/Disable normalizations of the firm representation.
320 * This flag guards transformations that normalize the Firm representation
321 * as removing Ids and Tuples, useless Phis, replacing SymConst(id) by
322 * Const(entity) and others.
323 * The transformations guarded by this flag are not guarded by flag
325 * Many algorithms operating on Firm can not deal with constructs in
326 * the non-normalized representation.
329 * @note ATTENTION: not all such transformations are guarded by a flag.
331 void set_opt_normalize (int value);
333 /** Enable/Disable precise exception context.
335 * If enabled, all exceptions form a barrier for values, as in the
344 * If precise exception handling is enabled, an exception handler see a == 1,
345 * else it might see a == 2.
346 * Enable this for languages with strict exception order like Java.
348 void set_opt_precise_exc_context(int value);
350 /** Enable/Disable Alias analysis.
352 * If enabled, memory disambiguation by alias analysis is used.
354 void set_opt_alias_analysis(int value);
356 /** Enable/Disable closed world assumption.
358 * If enabled, optimizations expect to know the "whole world", i.e. no
359 * external types or callers exist.
360 * This enables some powerful optimizations.
362 void set_opt_closed_world(int value);
365 * Save the current optimization state.
367 void save_optimization_state(optimization_state_t *state);
370 * Restore the current optimization state.
372 void restore_optimization_state(const optimization_state_t *state);
375 * Switches ALL optimizations off.
377 void all_optimizations_off(void);
380 * Possible verification modes.
382 typedef enum _firm_verification_t {
383 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
384 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
385 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
386 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
387 } firm_verification_t;
389 /** Select verification of IR nodes and types.
391 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
392 * Turn the verification off during development to check partial implementations.
394 void do_node_verification(firm_verification_t mode);
396 #endif /* _FIRM_IR_IRFLAG_H_ */