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 * @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 /** Enables/Disables constant folding optimization.
63 * If opt_constant_folding == 1 perform
64 * constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
65 * Default: opt_constant_folding == 1.
67 void set_opt_constant_folding(int value);
69 /** Enables/Disables algebraic simplifications.
71 * If opt_algebraic_simplification == 1 perform
72 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
73 * - simplification of tests ( !(a < b) ==> (a >= b))
74 * Default: opt_algebraic_simplification == 1.
76 void set_opt_algebraic_simplification(int value);
78 /** Enables/Disables common subexpression elimination.
80 * If opt_cse == 1 perform common subexpression elimination.
81 * Default: opt_cse == 1.
83 void set_opt_cse(int value);
85 /** Returns constant folding optimization setting. */
86 int get_opt_cse(void);
88 /** Enables/Disables global constant subexpression elimination.
90 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
91 * constant subexpression elimination for floating nodes. Intra
92 * procedure cse gets the graph into state "floating". It is necessary
93 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
94 * right after a call to local_optimize with global cse turned on.
95 * Default: opt_global_cse == 0.
97 void set_opt_global_cse(int value);
99 /** Enables/Disables usage of combo algorithm.
101 * If opt_combo == 1 perform combo optimization
102 * instead of combinations of optimiza_graph_df()/
103 * optimize_graph_cf()
104 * Default: opt_combo == 1.
106 void set_opt_combo(int value);
108 /** Enables/Disables strength reduction.
110 * If opt_strength_red == 1 perform strength reduction.
113 * Default: opt_strength_red = 1;
115 void set_opt_strength_red(int value);
117 /** Enables/Disables unreachable code elimination.
119 * If set, evaluate conditions of conditional branch and replace the
120 * branch with a Jmp/Bad Tuple.
122 * If opt_unreachable_code == 1 replace nodes (except Block,
123 * Phi and Tuple) with a Bad predecessor by the Bad node.
124 * Default: opt_unreachable_code == 1.
126 void set_opt_unreachable_code(int value);
128 /** Enables/Disables control flow optimizations.
130 * Performs Straightening, if simplifications and loop simplifications.
131 * Sets all separate control flow flags (control_flow_straightening,
132 * weak_simplification, strong_simplification and critical_edges).
134 void set_opt_control_flow(int value);
136 /** Enables/Disables Straightening. */
137 void set_opt_control_flow_straightening(int value);
139 /** Enables/Disables if simplifications in local optimizations. */
140 void set_opt_control_flow_weak_simplification(int value);
142 /** Enables/Disables strong if and loop simplification (in optimize_cf). */
143 void set_opt_control_flow_strong_simplification(int value);
145 /** Enable/Disable optimization of dynamic method dispatch.
147 * This flag enables/disables the optimization of dynamic method dispatch.
148 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
149 * the address of a function.
151 void set_opt_dyn_meth_dispatch(int value);
152 int get_opt_dyn_meth_dispatch(void);
154 /** Enable/Disable type optimization of cast nodes.
156 * Controls the optimizations in tropt.h. Default: on.
158 void set_opt_optimize_class_casts(int value);
160 /** Restricts the behavior of cast optimization.
162 * If set, downcast are not optimized if they might be
163 * illegal as in (Super)(Sub) (new Super()). Default:
164 * 0 == not suppressed.
166 void set_opt_suppress_downcast_optimization(int value);
167 int get_opt_suppress_downcast_optimization(void);
169 /** Enable/Disable floating of fragile ops.
171 * This flags enables/disables the floating of fragile operations.
172 * If this flag is on, fragile operations which are known to NOT raise
173 * an exception can be place to other basic blocks.
174 * Otherwise they remain in the block they were created.
176 void set_opt_fragile_ops(int value);
179 * Enable/Disable Confirm node removal during local optimization.
181 void set_opt_remove_confirm(int value);
184 * Enable/Disable scalar replacement optimization.
186 void set_opt_scalar_replacement(int value);
189 * Enable/Disable Null exception in Load and Store nodes only.
191 * If enabled, only Null pointer exception can occur at Load and
192 * store nodes. If it can be proved that the address input of these
193 * nodes is non-null, the exception edge can safely be removed.
194 * If disabled, other exceptions (like unaligned access, read-only memory,
197 * This flag is enabled by default.
199 void set_opt_ldst_only_null_ptr_exceptions(int value);
202 * Enable/Disable Selection based Null pointer check elimination.
204 * In languages, where all addresses are always Sel nodes, Null
205 * pointers can only occur as input to Sel nodes.
206 * If Null pointers are the only source for exceptions in Load and
207 * Store nodes (as typical in high level languages), we can eliminate
208 * exception edges from Load and Store when can prove that the Sel
209 * nodes representing the Load/Store address have non-null inputs.
210 * Enabling this flag enables this elimination.
212 * Enabling this flag is meaningless if ldst_non_null_exceptions is
215 * This flag should be set for Java style languages.
217 void set_opt_sel_based_null_check_elim(int value);
220 * Enable/Disable Global Null Pointer Test Elimination.
222 * In languages where it is illegal to dereference NULL pointer, doing
223 * so makes the pointer "valid non-null", else the program will stop
226 * This flag should be set for C style languages.
228 void set_opt_global_null_ptr_elimination(int value);
231 * Enable/Disable Automatic construction of Sync nodes during
234 * If this flags is set, sequential non-volatile Loads are automatically
235 * rearranged so that they can be executed in parallel by creating Sync nodes.
237 * This flag should be set for Java style languages.
239 void set_opt_auto_create_sync(int value);
241 /** Enable/Disable normalizations of the firm representation.
243 * This flag guards transformations that normalize the Firm representation
244 * as removing Ids and Tuples, useless Phis, replacing SymConst(id) by
245 * Const(entity) and others.
246 * The transformations guarded by this flag are not guarded by flag
248 * Many algorithms operating on Firm can not deal with constructs in
249 * the non-normalized representation.
252 * @note ATTENTION: not all such transformations are guarded by a flag.
254 void set_opt_normalize(int value);
257 * Enable/Disable ConvB() nodes with a "semantic behavior", i.e. a real
258 * operation that must be executed.
260 void set_opt_allow_conv_b(int value);
262 /** Enable/Disable precise exception context.
264 * If enabled, all exceptions form a barrier for values, as in the
273 * If precise exception handling is enabled, an exception handler see a == 1,
274 * else it might see a == 2.
275 * Enable this for languages with strict exception order like Java.
277 void set_opt_precise_exc_context(int value);
279 /** Enable/Disable Alias analysis.
281 * If enabled, memory disambiguation by alias analysis is used.
283 void set_opt_alias_analysis(int value);
285 /** Enable/Disable closed world assumption.
287 * If enabled, optimizations expect to know the "whole world", i.e. no
288 * external types or callers exist.
289 * This enables some powerful optimizations.
291 void set_opt_closed_world(int value);
294 * Save the current optimization state.
296 void save_optimization_state(optimization_state_t *state);
299 * Restore the current optimization state.
301 void restore_optimization_state(const optimization_state_t *state);
304 * Switches ALL optimizations off.
306 void all_optimizations_off(void);
309 * Possible verification modes.
311 typedef enum _firm_verification_t {
312 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
313 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
314 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
315 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
316 } firm_verification_t;
318 /** Select verification of IR nodes and types.
320 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
321 * Turn the verification off during development to check partial implementations.
323 void do_node_verification(firm_verification_t mode);