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 * @brief Flags to control optimizations.
23 * @author Christian Schaefer, Goetz Lindenmaier, Michael Beck
26 * Flags to customize the behavior of libfirm.
28 * There are the following groups of flags:
29 * 1. Optimization flags.
30 * a) There is a flag, 'optimize' to turn on/off all optimizations.
31 * b) There are flags for each individual optimization. Some flags turns
32 * transformations in several algorithms on/off.
33 * 2. Normalization flags.
34 * These flags steer transformations of the ir that improve it, as removing
35 * dump Phi nodes (one predecessor, all predecessors are equal ...), Ids, Tuples ...
37 * a) Flags to steer the level of the information.
38 * b) Flags to steer in which phase information should be dumped.
39 * 4. Verification flag
40 * This one controls the behavior of node and type verifications
42 #ifndef FIRM_IR_IRFLAG_H
43 #define FIRM_IR_IRFLAG_H
45 #include "firm_types.h"
48 * A container type to load/restore all optimizations
50 typedef unsigned optimization_state_t;
53 * This function enables/disables optimizations globally.
55 * If optimize == 0 no optimizations are performed at all.
56 * Default: optimize == 1.
58 void set_optimize (int value);
59 int get_optimize(void);
61 /** This function enables/disables output of information about phases and
62 * controls the verbosity level.
64 * 0: no output at all.
65 * 1: very short output
66 * >>1: very verbose output.
68 void set_firm_verbosity (int value);
69 int get_firm_verbosity (void);
71 /** Enables/Disables constant folding optimization.
73 * If opt_constant_folding == 1 perform
74 * - constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
75 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
76 * - simplification of tests ( !(a < b) ==> (a >= b))
77 * Default: opt_constant_folding == 1.
79 void set_opt_constant_folding (int value);
81 /** Enables/Disables loop unrolling.
83 * If opt_loop_unrolling == 1 perform loop_unrolling.
84 * See loop_unrolling.h.
86 * Default: opt_loop_unrolling = 1;
88 void set_opt_loop_unrolling (int value);
90 /** Enables/Disables output of information about loop unrolling.
92 void set_opt_loop_unrolling_verbose (int value);
94 /** Enables/Disables removal of redundant Loads and Stores.
96 * - Remove Store that overwrites a just stored value (WAW).
97 * - Remove Store if it stores a value just loaded (WAR with the same value).
98 * - Remove Load that loads a value just saved (RAW with the same value).
99 * - remove Load that loads a value already loaded (RAR)
100 * - replace Load of constant values with constants (RC)
102 void set_opt_redundant_loadstore(int value);
104 /** Enables/Disables common subexpression elimination.
106 * If opt_cse == 1 perform common subexpression elimination.
107 * Default: opt_cse == 1.
109 void set_opt_cse (int value);
111 /** Returns constant folding optimization setting. */
112 int get_opt_cse(void);
114 /** Enables/Disables global constant subexpression elimination.
116 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
117 * constant subexpression elimination for floating nodes. Intra
118 * procedure cse gets the graph into state "floating". It is necessary
119 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
120 * right after a call to local_optimize with global cse turned on.
121 * Default: opt_global_cse == 0.
123 void set_opt_global_cse (int value);
125 /** Enables/Disables strength reduction.
127 * If opt_strength_red == 1 perform strength reduction.
130 * Default: opt_strength_red = 1;
132 void set_opt_strength_red (int value);
134 /** Enables/Disables output of information about strength reduction.
136 void set_opt_strength_red_verbose (int value);
138 /** Enables/Disables unreachable code elimination.
140 * If set, evaluate conditions of conditional branch and replace the
141 * branch with a Jmp/Bad Tuple.
143 * If opt_unreachable_code == 1 replace nodes (except Block,
144 * Phi and Tuple) with a Bad predecessor by the Bad node.
145 * Default: opt_unreachable_code == 1.
147 void set_opt_unreachable_code(int value);
149 /** Enables/Disables control flow optimizations.
151 * Performs Straightening, if simplifications and loop simplifications.
152 * Sets all separate control flow flags (control_flow_straightening,
153 * weak_simplification, strong_simplification and critical_edges).
155 void set_opt_control_flow(int value);
157 /** Enables/Disables Straightening. */
158 void set_opt_control_flow_straightening(int value);
160 /** Enables/Disables if simplifications in local optimizations. */
161 void set_opt_control_flow_weak_simplification(int value);
163 /** Enables/Disables strong if and loop simplification (in optimize_cf). */
164 void set_opt_control_flow_strong_simplification(int value);
166 /** Enables/Disables reassociation.
168 * If opt_reassociation == 1 reassociation is performed.
169 * Default: opt_reassociation == 1.
171 void set_opt_reassociation(int value);
173 /** Enables/Disables dead node elimination.
175 * If opt_dead_node_elimination == 1 deallocate all dead nodes
176 * by copying the firm graph.
177 * Default: opt_dead_node_elimination == 1. */
178 void set_opt_dead_node_elimination (int value);
180 /** Enables/Disables dead method elimination.
182 * If opt_dead_method_elimination == 1 methods never called are
184 * Default: opt_dead_method_elimination == 1.
186 void set_opt_dead_method_elimination (int value);
187 void set_opt_dead_method_elimination_verbose (int value);
189 /** Enable/Disables method inlining.
191 * If opt_inline == 1 the inlining transformation is performed.
193 void set_opt_inline (int value);
195 /** Enable/Disable optimization of dynamic method dispatch.
197 * This flag enables/disables the optimization of dynamic method dispatch.
198 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
199 * the address of a function.
201 void set_opt_dyn_meth_dispatch (int value);
202 int get_opt_dyn_meth_dispatch (void);
204 /** Enable/Disable type optimization of cast nodes.
206 * Controls the optimizations in tropt.h. Default: on.
208 void set_opt_optimize_class_casts (int value);
209 void set_opt_optimize_class_casts_verbose (int value);
211 /** Restricts the behavior of cast optimization.
213 * If set, downcast are not optimized if they might be
214 * illegal as in (Super)(Sub) (new Super()). Default:
215 * 0 == not suppressed.
217 void set_opt_suppress_downcast_optimization(int value);
218 int get_opt_suppress_downcast_optimization(void);
220 /** Enable/Disable optimization of tail-recursion calls.
222 * This flag enables/disables the optimization tail-recursion call.
223 * If the flag is turned on tail-recursion calls are optimized into loops.
225 void set_opt_tail_recursion(int value);
226 void set_opt_tail_recursion_verbose(int value);
228 /** Enable/Disable floating of fragile ops.
230 * This flags enables/disables the floating of fragile operations.
231 * If this flag is on, fragile operations which are known to NOT raise
232 * an exception can be place to other basic blocks.
233 * Otherwise they remain in the block they were created.
235 void set_opt_fragile_ops(int value);
238 * Enable/Disable if conversion.
240 * If conversion tries to turn Conds into Mux nodes to eliminate
243 void set_opt_if_conversion(int value);
246 * Enable/Disable function call optimization.
248 * Function call optimization detects const and pure functions and
249 * allows the CSE of Call nodes. A const function is one that
250 * do only evaluate it's parameters and did not read or write memory
251 * to compute its results. Pure functions are allowed to read global memory.
253 void set_opt_function_call(int value);
256 * Enable/Disable Confirm node removal during local optimization.
258 void set_opt_remove_confirm(int value);
261 * Enable/Disable scalar replacement optimization.
263 void set_opt_scalar_replacement(int value);
264 void set_opt_scalar_replacement_verbose(int value);
267 * Enable/Disable Null exception in Load and Store nodes only.
269 * If enabled, only Null pointer exception can occur at Load and
270 * store nodes. If it can be proved that the address input of these
271 * nodes is non-null, the exception edge can safely be removed.
272 * If disabled, other exceptions (like unaligned access, read-only memory,
275 * This flag is enabled by default.
277 void set_opt_ldst_only_null_ptr_exceptions(int value);
280 * Enable/Disable Selection based Null pointer check elimination.
282 * In languages, where all addresses are always Sel nodes, Null
283 * pointers can only occur as input to Sel nodes.
284 * If Null pointers are the only source for exceptions in Load and
285 * Store nodes (as typical in high level languages), we can eliminate
286 * exception edges from Load and Store when can prove that the Sel
287 * nodes representing the Load/Store address have non-null inputs.
288 * Enabling this flag enables this elimination.
290 * Enabling this flag is meaningless if ldst_non_null_exceptions is
293 * This flags should be set for Java style languages.
295 void set_opt_sel_based_null_check_elim(int value);
298 * Enable/Disable Automatic construction of Sync nodes during
301 * If this flags is set, sequential non-volatile Loads are automatically
302 * rearranged so that they can be executed in parallel by creating Sync nodes.
304 * This flags should be set for Java style languages.
306 void set_opt_auto_create_sync(int value);
308 /** Enable/Disable normalizations of the firm representation.
310 * This flag guards transformations that normalize the Firm representation
311 * as removing Ids and Tuples, useless Phis, replacing SymConst(id) by
312 * Const(entity) and others.
313 * The transformations guarded by this flag are not guarded by flag
315 * Many algorithms operating on Firm can not deal with constructs in
316 * the non-normalized representation.
319 * @note ATTENTION: not all such transformations are guarded by a flag.
321 void set_opt_normalize (int value);
323 /** Enable/Disable precise exception context.
325 * If enabled, all exceptions form a barrier for values, as in the
334 * If precise exception handling is enabled, an exception handler see a == 1,
335 * else it might see a == 2.
336 * Enable this for languages with strict exception order like Java.
338 void set_opt_precise_exc_context(int value);
340 /** Enable/Disable Alias analysis.
342 * If enabled, memory disambiguation by alias analysis is used.
344 void set_opt_alias_analysis(int value);
346 /** Enable/Disable closed world assumption.
348 * If enabled, optimizations expect to know the "whole world", i.e. no
349 * external types or callers exist.
350 * This enables some powerful optimizations.
352 void set_opt_closed_world(int value);
355 * Save the current optimization state.
357 void save_optimization_state(optimization_state_t *state);
360 * Restore the current optimization state.
362 void restore_optimization_state(const optimization_state_t *state);
365 * Switches ALL optimizations off.
367 void all_optimizations_off(void);
370 * Possible verification modes.
372 typedef enum _firm_verification_t {
373 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
374 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
375 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
376 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
377 } firm_verification_t;
379 /** Select verification of IR nodes and types.
381 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
382 * Turn the verification off during development to check partial implementations.
384 void do_node_verification(firm_verification_t mode);