3 * File name: ir/ir/irflag.h
4 * Purpose: Flags to control optimizations.
5 * Author: Christian Schaefer, Goetz Lindenmaier
6 * Modified by: Michael Beck
9 * Copyright: (c) 1999-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 * Flags to customize the behavior of libfirm.
18 * @author Christian Schaefer
20 * There are the following groups of flags:
21 * 1. Optimization flags.
22 * a) There is a flag, 'optimize' to turn on/off all optimizations.
23 * b) There are flags for each individual optimization. Some flags turns
24 * transformations in several algorithms on/off.
25 * 2. Normalization flags.
26 * These flags steer transformations of the ir that improve it, as removing
27 * dump Phi nodes (one predecessor, all predecessors are equal ...), Ids, Tuples ...
29 * a) Flags to steer the level of the information.
30 * b) Flags to steer in which phase information should be dumped.
31 * 4. Verification flag
32 * This one controls the behavior of node and type verifications
34 #ifndef _FIRM_IR_IRFLAG_H_
35 #define _FIRM_IR_IRFLAG_H_
37 #include "firm_types.h"
40 * A container type to load/restore all optimizations
42 typedef unsigned optimization_state_t;
45 * This function enables/disables optimizations globally.
47 * If optimize == 0 no optimizations are performed at all.
48 * Default: optimize == 1.
50 void set_optimize (int value);
51 int get_optimize(void);
53 /** This function enables/disables output of information about phases and
54 * controls the verbosity level.
56 * 0: no output at all.
57 * 1: very short output
58 * >>1: very verbose output.
60 void set_firm_verbosity (int value);
61 int get_firm_verbosity (void);
63 /** Enables/Disables constant folding optimization.
65 * If opt_constant_folding == 1 perform
66 * - constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
67 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
68 * - simplification of tests ( !(a < b) ==> (a >= b))
69 * Default: opt_constant_folding == 1.
71 void set_opt_constant_folding (int value);
73 /** Enables/Disables loop unrolling.
75 * If opt_loop_unrolling == 1 perform loop_unrolling.
76 * See loop_unrolling.h.
78 * Default: opt_loop_unrolling = 1;
80 void set_opt_loop_unrolling (int value);
82 /** Enables/Disables output of information about loop unrolling.
84 void set_opt_loop_unrolling_verbose (int value);
86 /** Enables/Disables removal of redundant Loads and Stores.
88 * - Remove Store that overwrites a just stored value (WAW).
89 * - Remove Store if it stores a value just loaded (WAR with the same value).
90 * - Remove Load that loads a value just saved (RAW with the same value).
91 * - remove Load that loads a value already loaded (RAR)
92 * - replace Load of constant values with constants (RC)
94 void set_opt_redundant_loadstore(int value);
96 /** Enables/Disables common subexpression elimination.
98 * If opt_cse == 1 perform common subexpression elimination.
99 * Default: opt_cse == 1.
101 void set_opt_cse (int value);
103 /** Returns constant folding optimization setting. */
104 int get_opt_cse(void);
106 /** Enables/Disables global constant subexpression elimination.
108 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
109 * constant subexpression elimination for floating nodes. Intra
110 * procedure cse gets the graph into state "floating". It is necessary
111 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
112 * right after a call to local_optimize with global cse turned on.
113 * Default: opt_global_cse == 0.
115 void set_opt_global_cse (int value);
117 /** Enables/Disables strength reduction.
119 * If opt_strength_red == 1 perform strength reduction.
122 * Default: opt_strength_red = 1;
124 void set_opt_strength_red (int value);
126 /** Enables/Disables output of information about strength reduction.
128 void set_opt_strength_red_verbose (int value);
130 /** Enables/Disables unreachable code elimination.
132 * If set, evaluate conditions of conditional branch and replace the
133 * branch with a Jmp/Bad Tuple.
135 * If opt_unreachable_code == 1 replace nodes (except Block,
136 * Phi and Tuple) with a Bad predecessor by the Bad node.
137 * Default: opt_unreachable_code == 1.
139 void set_opt_unreachable_code(int value);
141 /** Enables/Disables control flow optimizations.
143 * Performs Straightening, if simplifications and loop simplifications.
144 * Sets all separate control flow flags (control_flow_straightening,
145 * weak_simplification, strong_simplification and critical_edges).
147 void set_opt_control_flow(int value);
149 /** Enables/Disables Straightening. */
150 void set_opt_control_flow_straightening(int value);
152 /** Enables/Disables if simplifications in local optimizations. */
153 void set_opt_control_flow_weak_simplification(int value);
155 /** Enables/Disables strong if and loop simplification (in optimize_cf). */
156 void set_opt_control_flow_strong_simplification(int value);
158 /** Enables/Disables reassociation.
160 * If opt_reassociation == 1 reassociation is performed.
161 * Default: opt_reassociation == 1.
163 void set_opt_reassociation(int value);
165 /** Enables/Disables dead node elimination.
167 * If opt_dead_node_elimination == 1 deallocate all dead nodes
168 * by copying the firm graph.
169 * Default: opt_dead_node_elimination == 1. */
170 void set_opt_dead_node_elimination (int value);
172 /** Enables/Disables dead method elimination.
174 * If opt_dead_method_elimination == 1 methods never called are
176 * Default: opt_dead_method_elimination == 1.
178 void set_opt_dead_method_elimination (int value);
179 void set_opt_dead_method_elimination_verbose (int value);
181 /** Enable/Disables method inlining.
183 * If opt_inline == 1 the inlining transformation is performed.
185 void set_opt_inline (int value);
187 /** Enable/Disable optimization of dynamic method dispatch.
189 * This flag enables/disables the optimization of dynamic method dispatch.
190 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
191 * the address of a function.
193 void set_opt_dyn_meth_dispatch (int value);
194 int get_opt_dyn_meth_dispatch (void);
196 /** Enable/Disable type optimization of cast nodes.
198 * Controls the optimizations in tropt.h. Default: on.
200 void set_opt_optimize_class_casts (int value);
201 void set_opt_optimize_class_casts_verbose (int value);
203 /** Restricts the behavior of cast optimization.
205 * If set, downcast are not optimized if they might be
206 * illegal as in (Super)(Sub) (new Super()). Default:
207 * 0 == not suppressed.
209 void set_opt_suppress_downcast_optimization(int value);
210 int get_opt_suppress_downcast_optimization(void);
212 /** Enable/Disable optimization of tail-recursion calls.
214 * This flag enables/disables the optimization tail-recursion call.
215 * If the flag is turned on tail-recursion calls are optimized into loops.
217 void set_opt_tail_recursion(int value);
218 void set_opt_tail_recursion_verbose(int value);
220 /** Enable/Disable floating of fragile ops.
222 * This flags enables/disables the floating of fragile operations.
223 * If this flag is on, fragile operations which are known to NOT raise
224 * an exception can be place to other basic blocks.
225 * Otherwise they remain in the block they were created.
227 void set_opt_fragile_ops(int value);
230 * Enable/Disable if conversion.
232 * If conversion tries to turn Conds into Mux nodes to eliminate
235 void set_opt_if_conversion(int value);
238 * Enable/Disable function call optimization.
240 * Function call optimization detects const and pure functions and
241 * allows the CSE of Call nodes. A const function is one that
242 * do only evaluate it's parameters and did not read or write memory
243 * to compute its results. Pure functions are allowed to read global memory.
245 void set_opt_function_call(int value);
248 * Enable/Disable Confirm node removal during local optimization.
250 void set_opt_remove_confirm(int value);
253 * Enable/Disable scalar replacement optimization.
255 void set_opt_scalar_replacement(int value);
256 void set_opt_scalar_replacement_verbose(int value);
259 * Enable/Disable Null exception in Load and Store nodes only.
261 * If enabled, only Null pointer exception can occur at Load and
262 * store nodes. If it can be proved that the address input of these
263 * nodes is non-null, the exception edge can safely be removed.
264 * If disabled, other exceptions (like unaligned access, read-only memory,
267 * This flag is enabled by default.
269 void set_opt_ldst_only_null_ptr_exceptions(int value);
272 * Enable/Disable Selection based Null pointer check elimination.
274 * In languages, where all addresses are always Sel nodes, Null
275 * pointers can only occur as input to Sel nodes.
276 * If Null pointers are the only source for exceptions in Load and
277 * Store nodes (as typical in high level languages), we can eliminate
278 * exception edges from Load and Store when can prove that the Sel
279 * nodes representing the Load/Store address have non-null inputs.
280 * Enabling this flag enables this elimination.
282 * Enabling this flag is meaningless if ldst_non_null_exceptions is
285 * This flags should be set for Java style languages.
287 void set_opt_sel_based_null_check_elim(int value);
290 * Enable/Disable Automatic construction of Sync nodes during
293 * If this flags is set, sequential non-volatile Loads are automatically
294 * rearranged so that they can be executed in parallel by creating Sync nodes.
296 * This flags should be set for Java style languages.
298 void set_opt_auto_create_sync(int value);
300 /** Enable/Disable normalizations of the firm representation.
302 * This flag guards transformations that normalize the Firm representation
303 * as removing Ids and Tuples, useless Phis, replacing SymConst(id) by
304 * Const(entity) and others.
305 * The transformations guarded by this flag are not guarded by flag
307 * Many algorithms operating on Firm can not deal with constructs in
308 * the non-normalized representation.
311 * @note ATTENTION: not all such transformations are guarded by a flag.
313 void set_opt_normalize (int value);
315 /** Enable/Disable precise exception context.
317 * If enabled, all exceptions form a barrier for values, as in the
326 * If precise exception handling is enabled, an exception handler see a == 1,
327 * else it might see a == 2.
328 * Enable this for languages with strict exception order like Java.
330 void set_opt_precise_exc_context(int value);
332 /** Enable/Disable Alias analysis.
334 * If enabled, memory disambiguation by alias analysis is used.
336 void set_opt_alias_analysis(int value);
338 /** Enable/Disable closed world assumption.
340 * If enabled, optimizations expect to know the "whole world", i.e. no
341 * external types or callers exist.
342 * This enables some powerful optimizations.
344 void set_opt_closed_world(int value);
347 * Save the current optimization state.
349 void save_optimization_state(optimization_state_t *state);
352 * Restore the current optimization state.
354 void restore_optimization_state(const optimization_state_t *state);
357 * Switches ALL optimizations off.
359 void all_optimizations_off(void);
362 * Possible verification modes.
364 typedef enum _firm_verification_t {
365 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
366 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
367 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
368 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
369 } firm_verification_t;
371 /** Select verification of IR nodes and types.
373 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
374 * Turn the verification off during development to check partial implementations.
376 void do_node_verification(firm_verification_t mode);
378 #endif /* _FIRM_IR_IRFLAG_H_ */