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"
49 * A container type to load/restore all optimizations
51 typedef unsigned optimization_state_t;
54 * This function enables/disables optimizations globally.
56 * If optimize == 0 no optimizations are performed at all.
57 * Default: optimize == 1.
59 FIRM_API void set_optimize(int value);
60 FIRM_API int get_optimize(void);
62 /** Enables/Disables constant folding optimization.
64 * If opt_constant_folding == 1 perform
65 * constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
66 * Default: opt_constant_folding == 1.
68 FIRM_API void set_opt_constant_folding(int value);
70 /** Enables/Disables algebraic simplifications.
72 * If opt_algebraic_simplification == 1 perform
73 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
74 * - simplification of tests ( !(a < b) ==> (a >= b))
75 * Default: opt_algebraic_simplification == 1.
77 FIRM_API void set_opt_algebraic_simplification(int value);
79 /** Enables/Disables common subexpression elimination.
81 * If opt_cse == 1 perform common subexpression elimination.
82 * Default: opt_cse == 1.
84 FIRM_API void set_opt_cse(int value);
86 /** Returns constant folding optimization setting. */
87 FIRM_API int get_opt_cse(void);
89 /** Enables/Disables global constant subexpression elimination.
91 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
92 * constant subexpression elimination for floating nodes. Intra
93 * procedure cse gets the graph into state "floating". It is necessary
94 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
95 * right after a call to local_optimize with global cse turned on.
96 * Default: opt_global_cse == 0.
98 FIRM_API void set_opt_global_cse(int value);
100 /** Enables/Disables unreachable code elimination.
102 * If set, evaluate conditions of conditional branch and replace the
103 * branch with a Jmp/Bad Tuple.
105 * If opt_unreachable_code == 1 replace nodes (except Block,
106 * Phi and Tuple) with a Bad predecessor by the Bad node.
107 * Default: opt_unreachable_code == 1.
109 FIRM_API void set_opt_unreachable_code(int value);
111 /** Enable/Disable optimization of dynamic method dispatch.
113 * This flag enables/disables the optimization of dynamic method dispatch.
114 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
115 * the address of a function.
117 FIRM_API void set_opt_dyn_meth_dispatch(int value);
118 FIRM_API int get_opt_dyn_meth_dispatch(void);
120 /** Restricts the behavior of cast optimization.
122 * If set, downcast are not optimized if they might be
123 * illegal as in (Super)(Sub) (new Super()). Default:
124 * 0 == not suppressed.
126 FIRM_API void set_opt_suppress_downcast_optimization(int value);
127 FIRM_API int get_opt_suppress_downcast_optimization(void);
130 * Enable/Disable Null exception in Load and Store nodes only.
132 * If enabled, only Null pointer exception can occur at Load and
133 * store nodes. If it can be proved that the address input of these
134 * nodes is non-null, the exception edge can safely be removed.
135 * If disabled, other exceptions (like unaligned access, read-only memory,
138 * This flag is enabled by default.
140 FIRM_API void set_opt_ldst_only_null_ptr_exceptions(int value);
143 * Enable/Disable Selection based Null pointer check elimination.
145 * In languages, where all addresses are always Sel nodes, Null
146 * pointers can only occur as input to Sel nodes.
147 * If Null pointers are the only source for exceptions in Load and
148 * Store nodes (as typical in high level languages), we can eliminate
149 * exception edges from Load and Store when can prove that the Sel
150 * nodes representing the Load/Store address have non-null inputs.
151 * Enabling this flag enables this elimination.
153 * Enabling this flag is meaningless if ldst_non_null_exceptions is
156 * This flag should be set for Java style languages.
158 FIRM_API void set_opt_sel_based_null_check_elim(int value);
161 * Enable/Disable Global Null Pointer Test Elimination.
163 * In languages where it is illegal to dereference NULL pointer, doing
164 * so makes the pointer "valid non-null", else the program will stop
167 * This flag should be set for C style languages.
169 FIRM_API void set_opt_global_null_ptr_elimination(int value);
172 * Enable/Disable Automatic construction of Sync nodes during
175 * If this flags is set, sequential non-volatile Loads are automatically
176 * rearranged so that they can be executed in parallel by creating Sync nodes.
178 * This flag should be set for Java style languages.
180 FIRM_API void set_opt_auto_create_sync(int value);
182 /** Enable/Disable Alias analysis.
184 * If enabled, memory disambiguation by alias analysis is used.
186 FIRM_API void set_opt_alias_analysis(int value);
188 /** Enable/Disable closed world assumption.
190 * If enabled, optimizations expect to know the "whole world", i.e. no
191 * external types or callers exist.
192 * This enables some powerful optimizations.
194 FIRM_API void set_opt_closed_world(int value);
197 * Save the current optimization state.
199 FIRM_API void save_optimization_state(optimization_state_t *state);
202 * Restore the current optimization state.
204 FIRM_API void restore_optimization_state(const optimization_state_t *state);
207 * Switches ALL optimizations off.
209 FIRM_API void all_optimizations_off(void);
212 * Possible verification modes.
214 typedef enum firm_verification_t {
215 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
216 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
217 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
218 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
219 } firm_verification_t;
221 /** Select verification of IR nodes and types.
223 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
224 * Turn the verification off during development to check partial implementations.
226 FIRM_API void do_node_verification(firm_verification_t mode);