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1 /* -*- c++ -*- */
2 /*
3  * Copyright © 2010 Intel Corporation
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22  * DEALINGS IN THE SOFTWARE.
23  */
24 
25 #pragma once
26 #ifndef IR_H
27 #define IR_H
28 
29 #include <stdio.h>
30 #include <stdlib.h>
31 
32 #include "ralloc.h"
33 #include "glsl_types.h"
34 #include "list.h"
35 #include "ir_visitor.h"
36 #include "ir_hierarchical_visitor.h"
37 #include "main/mtypes.h"
38 
39 /**
40  * \defgroup IR Intermediate representation nodes
41  *
42  * @{
43  */
44 
45 /**
46  * Class tags
47  *
48  * Each concrete class derived from \c ir_instruction has a value in this
49  * enumerant.  The value for the type is stored in \c ir_instruction::ir_type
50  * by the constructor.  While using type tags is not very C++, it is extremely
51  * convenient.  For example, during debugging you can simply inspect
52  * \c ir_instruction::ir_type to find out the actual type of the object.
53  *
54  * In addition, it is possible to use a switch-statement based on \c
55  * \c ir_instruction::ir_type to select different behavior for different object
56  * types.  For functions that have only slight differences for several object
57  * types, this allows writing very straightforward, readable code.
58  */
59 enum ir_node_type {
60    /**
61     * Zero is unused so that the IR validator can detect cases where
62     * \c ir_instruction::ir_type has not been initialized.
63     */
64    ir_type_unset,
65    ir_type_variable,
66    ir_type_assignment,
67    ir_type_call,
68    ir_type_constant,
69    ir_type_dereference_array,
70    ir_type_dereference_record,
71    ir_type_dereference_variable,
72    ir_type_discard,
73    ir_type_expression,
74    ir_type_function,
75    ir_type_function_signature,
76    ir_type_if,
77    ir_type_loop,
78    ir_type_loop_jump,
79    ir_type_return,
80    ir_type_swizzle,
81    ir_type_texture,
82    ir_type_max /**< maximum ir_type enum number, for validation */
83 };
84 
85 /**
86  * Base class of all IR instructions
87  */
88 class ir_instruction : public exec_node {
89 public:
90    enum ir_node_type ir_type;
91 
92    /**
93     * GCC 4.7+ and clang warn when deleting an ir_instruction unless
94     * there's a virtual destructor present.  Because we almost
95     * universally use ralloc for our memory management of
96     * ir_instructions, the destructor doesn't need to do any work.
97     */
~ir_instruction()98    virtual ~ir_instruction()
99    {
100    }
101 
102    /** ir_print_visitor helper for debugging. */
103    void print(void) const;
104 
105    virtual void accept(ir_visitor *) = 0;
106    virtual ir_visitor_status accept(ir_hierarchical_visitor *) = 0;
107    virtual ir_instruction *clone(void *mem_ctx,
108 				 struct hash_table *ht) const = 0;
109 
110    /**
111     * \name IR instruction downcast functions
112     *
113     * These functions either cast the object to a derived class or return
114     * \c NULL if the object's type does not match the specified derived class.
115     * Additional downcast functions will be added as needed.
116     */
117    /*@{*/
as_variable()118    virtual class ir_variable *          as_variable()         { return NULL; }
as_function()119    virtual class ir_function *          as_function()         { return NULL; }
as_dereference()120    virtual class ir_dereference *       as_dereference()      { return NULL; }
as_dereference_array()121    virtual class ir_dereference_array *	as_dereference_array() { return NULL; }
as_dereference_variable()122    virtual class ir_dereference_variable *as_dereference_variable() { return NULL; }
as_expression()123    virtual class ir_expression *        as_expression()       { return NULL; }
as_rvalue()124    virtual class ir_rvalue *            as_rvalue()           { return NULL; }
as_loop()125    virtual class ir_loop *              as_loop()             { return NULL; }
as_assignment()126    virtual class ir_assignment *        as_assignment()       { return NULL; }
as_call()127    virtual class ir_call *              as_call()             { return NULL; }
as_return()128    virtual class ir_return *            as_return()           { return NULL; }
as_if()129    virtual class ir_if *                as_if()               { return NULL; }
as_swizzle()130    virtual class ir_swizzle *           as_swizzle()          { return NULL; }
as_constant()131    virtual class ir_constant *          as_constant()         { return NULL; }
as_discard()132    virtual class ir_discard *           as_discard()          { return NULL; }
133    /*@}*/
134 
135 protected:
ir_instruction()136    ir_instruction()
137    {
138       ir_type = ir_type_unset;
139    }
140 };
141 
142 
143 /**
144  * The base class for all "values"/expression trees.
145  */
146 class ir_rvalue : public ir_instruction {
147 public:
148    const struct glsl_type *type;
149 
150    virtual ir_rvalue *clone(void *mem_ctx, struct hash_table *) const;
151 
accept(ir_visitor * v)152    virtual void accept(ir_visitor *v)
153    {
154       v->visit(this);
155    }
156 
157    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
158 
159    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
160 
as_rvalue()161    virtual ir_rvalue * as_rvalue()
162    {
163       return this;
164    }
165 
166    ir_rvalue *as_rvalue_to_saturate();
167 
is_lvalue()168    virtual bool is_lvalue() const
169    {
170       return false;
171    }
172 
173    /**
174     * Get the variable that is ultimately referenced by an r-value
175     */
variable_referenced()176    virtual ir_variable *variable_referenced() const
177    {
178       return NULL;
179    }
180 
181 
182    /**
183     * If an r-value is a reference to a whole variable, get that variable
184     *
185     * \return
186     * Pointer to a variable that is completely dereferenced by the r-value.  If
187     * the r-value is not a dereference or the dereference does not access the
188     * entire variable (i.e., it's just one array element, struct field), \c NULL
189     * is returned.
190     */
whole_variable_referenced()191    virtual ir_variable *whole_variable_referenced()
192    {
193       return NULL;
194    }
195 
196    /**
197     * Determine if an r-value has the value zero
198     *
199     * The base implementation of this function always returns \c false.  The
200     * \c ir_constant class over-rides this function to return \c true \b only
201     * for vector and scalar types that have all elements set to the value
202     * zero (or \c false for booleans).
203     *
204     * \sa ir_constant::has_value, ir_rvalue::is_one, ir_rvalue::is_negative_one,
205     *     ir_constant::is_basis
206     */
207    virtual bool is_zero() const;
208 
209    /**
210     * Determine if an r-value has the value one
211     *
212     * The base implementation of this function always returns \c false.  The
213     * \c ir_constant class over-rides this function to return \c true \b only
214     * for vector and scalar types that have all elements set to the value
215     * one (or \c true for booleans).
216     *
217     * \sa ir_constant::has_value, ir_rvalue::is_zero, ir_rvalue::is_negative_one,
218     *     ir_constant::is_basis
219     */
220    virtual bool is_one() const;
221 
222    /**
223     * Determine if an r-value has the value negative one
224     *
225     * The base implementation of this function always returns \c false.  The
226     * \c ir_constant class over-rides this function to return \c true \b only
227     * for vector and scalar types that have all elements set to the value
228     * negative one.  For boolean types, the result is always \c false.
229     *
230     * \sa ir_constant::has_value, ir_rvalue::is_zero, ir_rvalue::is_one
231     *     ir_constant::is_basis
232     */
233    virtual bool is_negative_one() const;
234 
235    /**
236     * Determine if an r-value is a basis vector
237     *
238     * The base implementation of this function always returns \c false.  The
239     * \c ir_constant class over-rides this function to return \c true \b only
240     * for vector and scalar types that have one element set to the value one,
241     * and the other elements set to the value zero.  For boolean types, the
242     * result is always \c false.
243     *
244     * \sa ir_constant::has_value, ir_rvalue::is_zero, ir_rvalue::is_one,
245     *     is_constant::is_negative_one
246     */
247    virtual bool is_basis() const;
248 
249 
250    /**
251     * Return a generic value of error_type.
252     *
253     * Allocation will be performed with 'mem_ctx' as ralloc owner.
254     */
255    static ir_rvalue *error_value(void *mem_ctx);
256 
257 protected:
258    ir_rvalue();
259 };
260 
261 
262 /**
263  * Variable storage classes
264  */
265 enum ir_variable_mode {
266    ir_var_auto = 0,     /**< Function local variables and globals. */
267    ir_var_uniform,      /**< Variable declared as a uniform. */
268    ir_var_in,
269    ir_var_out,
270    ir_var_inout,
271    ir_var_const_in,	/**< "in" param that must be a constant expression */
272    ir_var_system_value, /**< Ex: front-face, instance-id, etc. */
273    ir_var_temporary	/**< Temporary variable generated during compilation. */
274 };
275 
276 /**
277  * \brief Layout qualifiers for gl_FragDepth.
278  *
279  * The AMD/ARB_conservative_depth extensions allow gl_FragDepth to be redeclared
280  * with a layout qualifier.
281  */
282 enum ir_depth_layout {
283     ir_depth_layout_none, /**< No depth layout is specified. */
284     ir_depth_layout_any,
285     ir_depth_layout_greater,
286     ir_depth_layout_less,
287     ir_depth_layout_unchanged
288 };
289 
290 /**
291  * \brief Convert depth layout qualifier to string.
292  */
293 const char*
294 depth_layout_string(ir_depth_layout layout);
295 
296 /**
297  * Description of built-in state associated with a uniform
298  *
299  * \sa ir_variable::state_slots
300  */
301 struct ir_state_slot {
302    int tokens[5];
303    int swizzle;
304 };
305 
306 class ir_variable : public ir_instruction {
307 public:
308    ir_variable(const struct glsl_type *, const char *, ir_variable_mode);
309 
310    virtual ir_variable *clone(void *mem_ctx, struct hash_table *ht) const;
311 
as_variable()312    virtual ir_variable *as_variable()
313    {
314       return this;
315    }
316 
accept(ir_visitor * v)317    virtual void accept(ir_visitor *v)
318    {
319       v->visit(this);
320    }
321 
322    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
323 
324 
325    /**
326     * Get the string value for the interpolation qualifier
327     *
328     * \return The string that would be used in a shader to specify \c
329     * mode will be returned.
330     *
331     * This function is used to generate error messages of the form "shader
332     * uses %s interpolation qualifier", so in the case where there is no
333     * interpolation qualifier, it returns "no".
334     *
335     * This function should only be used on a shader input or output variable.
336     */
337    const char *interpolation_string() const;
338 
339    /**
340     * Determine how this variable should be interpolated based on its
341     * interpolation qualifier (if present), whether it is gl_Color or
342     * gl_SecondaryColor, and whether flatshading is enabled in the current GL
343     * state.
344     *
345     * The return value will always be either INTERP_QUALIFIER_SMOOTH,
346     * INTERP_QUALIFIER_NOPERSPECTIVE, or INTERP_QUALIFIER_FLAT.
347     */
348    glsl_interp_qualifier determine_interpolation_mode(bool flat_shade);
349 
350    /**
351     * Declared type of the variable
352     */
353    const struct glsl_type *type;
354 
355    /**
356     * Declared name of the variable
357     */
358    const char *name;
359 
360    /**
361     * Highest element accessed with a constant expression array index
362     *
363     * Not used for non-array variables.
364     */
365    unsigned max_array_access;
366 
367    /**
368     * Is the variable read-only?
369     *
370     * This is set for variables declared as \c const, shader inputs,
371     * and uniforms.
372     */
373    unsigned read_only:1;
374    unsigned centroid:1;
375    unsigned invariant:1;
376 
377    /**
378     * Has this variable been used for reading or writing?
379     *
380     * Several GLSL semantic checks require knowledge of whether or not a
381     * variable has been used.  For example, it is an error to redeclare a
382     * variable as invariant after it has been used.
383     *
384     * This is only maintained in the ast_to_hir.cpp path, not in
385     * Mesa's fixed function or ARB program paths.
386     */
387    unsigned used:1;
388 
389    /**
390     * Has this variable been statically assigned?
391     *
392     * This answers whether the variable was assigned in any path of
393     * the shader during ast_to_hir.  This doesn't answer whether it is
394     * still written after dead code removal, nor is it maintained in
395     * non-ast_to_hir.cpp (GLSL parsing) paths.
396     */
397    unsigned assigned:1;
398 
399    /**
400     * Storage class of the variable.
401     *
402     * \sa ir_variable_mode
403     */
404    unsigned mode:3;
405 
406    /**
407     * Interpolation mode for shader inputs / outputs
408     *
409     * \sa ir_variable_interpolation
410     */
411    unsigned interpolation:2;
412 
413    /**
414     * \name ARB_fragment_coord_conventions
415     * @{
416     */
417    unsigned origin_upper_left:1;
418    unsigned pixel_center_integer:1;
419    /*@}*/
420 
421    /**
422     * Was the location explicitly set in the shader?
423     *
424     * If the location is explicitly set in the shader, it \b cannot be changed
425     * by the linker or by the API (e.g., calls to \c glBindAttribLocation have
426     * no effect).
427     */
428    unsigned explicit_location:1;
429    unsigned explicit_index:1;
430 
431    /**
432     * Does this variable have an initializer?
433     *
434     * This is used by the linker to cross-validiate initializers of global
435     * variables.
436     */
437    unsigned has_initializer:1;
438 
439    /**
440     * \brief Layout qualifier for gl_FragDepth.
441     *
442     * This is not equal to \c ir_depth_layout_none if and only if this
443     * variable is \c gl_FragDepth and a layout qualifier is specified.
444     */
445    ir_depth_layout depth_layout;
446 
447    /**
448     * Storage location of the base of this variable
449     *
450     * The precise meaning of this field depends on the nature of the variable.
451     *
452     *   - Vertex shader input: one of the values from \c gl_vert_attrib.
453     *   - Vertex shader output: one of the values from \c gl_vert_result.
454     *   - Fragment shader input: one of the values from \c gl_frag_attrib.
455     *   - Fragment shader output: one of the values from \c gl_frag_result.
456     *   - Uniforms: Per-stage uniform slot number for default uniform block.
457     *   - Uniforms: Index within the uniform block definition for UBO members.
458     *   - Other: This field is not currently used.
459     *
460     * If the variable is a uniform, shader input, or shader output, and the
461     * slot has not been assigned, the value will be -1.
462     */
463    int location;
464 
465    /**
466     * Uniform block number for uniforms.
467     *
468     * This index is into the shader's list of uniform blocks, not the
469     * linked program's merged list.
470     *
471     * If the variable is not in a uniform block, the value will be -1.
472     */
473    int uniform_block;
474 
475    /**
476     * output index for dual source blending.
477     */
478    int index;
479 
480    /**
481     * Built-in state that backs this uniform
482     *
483     * Once set at variable creation, \c state_slots must remain invariant.
484     * This is because, ideally, this array would be shared by all clones of
485     * this variable in the IR tree.  In other words, we'd really like for it
486     * to be a fly-weight.
487     *
488     * If the variable is not a uniform, \c num_state_slots will be zero and
489     * \c state_slots will be \c NULL.
490     */
491    /*@{*/
492    unsigned num_state_slots;    /**< Number of state slots used */
493    ir_state_slot *state_slots;  /**< State descriptors. */
494    /*@}*/
495 
496    /**
497     * Emit a warning if this variable is accessed.
498     */
499    const char *warn_extension;
500 
501    /**
502     * Value assigned in the initializer of a variable declared "const"
503     */
504    ir_constant *constant_value;
505 
506    /**
507     * Constant expression assigned in the initializer of the variable
508     *
509     * \warning
510     * This field and \c ::constant_value are distinct.  Even if the two fields
511     * refer to constants with the same value, they must point to separate
512     * objects.
513     */
514    ir_constant *constant_initializer;
515 };
516 
517 
518 /*@{*/
519 /**
520  * The representation of a function instance; may be the full definition or
521  * simply a prototype.
522  */
523 class ir_function_signature : public ir_instruction {
524    /* An ir_function_signature will be part of the list of signatures in
525     * an ir_function.
526     */
527 public:
528    ir_function_signature(const glsl_type *return_type);
529 
530    virtual ir_function_signature *clone(void *mem_ctx,
531 					struct hash_table *ht) const;
532    ir_function_signature *clone_prototype(void *mem_ctx,
533 					  struct hash_table *ht) const;
534 
accept(ir_visitor * v)535    virtual void accept(ir_visitor *v)
536    {
537       v->visit(this);
538    }
539 
540    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
541 
542    /**
543     * Attempt to evaluate this function as a constant expression,
544     * given a list of the actual parameters and the variable context.
545     * Returns NULL for non-built-ins.
546     */
547    ir_constant *constant_expression_value(exec_list *actual_parameters, struct hash_table *variable_context);
548 
549    /**
550     * Get the name of the function for which this is a signature
551     */
552    const char *function_name() const;
553 
554    /**
555     * Get a handle to the function for which this is a signature
556     *
557     * There is no setter function, this function returns a \c const pointer,
558     * and \c ir_function_signature::_function is private for a reason.  The
559     * only way to make a connection between a function and function signature
560     * is via \c ir_function::add_signature.  This helps ensure that certain
561     * invariants (i.e., a function signature is in the list of signatures for
562     * its \c _function) are met.
563     *
564     * \sa ir_function::add_signature
565     */
function()566    inline const class ir_function *function() const
567    {
568       return this->_function;
569    }
570 
571    /**
572     * Check whether the qualifiers match between this signature's parameters
573     * and the supplied parameter list.  If not, returns the name of the first
574     * parameter with mismatched qualifiers (for use in error messages).
575     */
576    const char *qualifiers_match(exec_list *params);
577 
578    /**
579     * Replace the current parameter list with the given one.  This is useful
580     * if the current information came from a prototype, and either has invalid
581     * or missing parameter names.
582     */
583    void replace_parameters(exec_list *new_params);
584 
585    /**
586     * Function return type.
587     *
588     * \note This discards the optional precision qualifier.
589     */
590    const struct glsl_type *return_type;
591 
592    /**
593     * List of ir_variable of function parameters.
594     *
595     * This represents the storage.  The paramaters passed in a particular
596     * call will be in ir_call::actual_paramaters.
597     */
598    struct exec_list parameters;
599 
600    /** Whether or not this function has a body (which may be empty). */
601    unsigned is_defined:1;
602 
603    /** Whether or not this function signature is a built-in. */
604    unsigned is_builtin:1;
605 
606    /** Body of instructions in the function. */
607    struct exec_list body;
608 
609 private:
610    /** Function of which this signature is one overload. */
611    class ir_function *_function;
612 
613    /** Function signature of which this one is a prototype clone */
614    const ir_function_signature *origin;
615 
616    friend class ir_function;
617 
618    /**
619     * Helper function to run a list of instructions for constant
620     * expression evaluation.
621     *
622     * The hash table represents the values of the visible variables.
623     * There are no scoping issues because the table is indexed on
624     * ir_variable pointers, not variable names.
625     *
626     * Returns false if the expression is not constant, true otherwise,
627     * and the value in *result if result is non-NULL.
628     */
629    bool constant_expression_evaluate_expression_list(const struct exec_list &body,
630 						     struct hash_table *variable_context,
631 						     ir_constant **result);
632 };
633 
634 
635 /**
636  * Header for tracking multiple overloaded functions with the same name.
637  * Contains a list of ir_function_signatures representing each of the
638  * actual functions.
639  */
640 class ir_function : public ir_instruction {
641 public:
642    ir_function(const char *name);
643 
644    virtual ir_function *clone(void *mem_ctx, struct hash_table *ht) const;
645 
as_function()646    virtual ir_function *as_function()
647    {
648       return this;
649    }
650 
accept(ir_visitor * v)651    virtual void accept(ir_visitor *v)
652    {
653       v->visit(this);
654    }
655 
656    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
657 
add_signature(ir_function_signature * sig)658    void add_signature(ir_function_signature *sig)
659    {
660       sig->_function = this;
661       this->signatures.push_tail(sig);
662    }
663 
664    /**
665     * Get an iterator for the set of function signatures
666     */
iterator()667    exec_list_iterator iterator()
668    {
669       return signatures.iterator();
670    }
671 
672    /**
673     * Find a signature that matches a set of actual parameters, taking implicit
674     * conversions into account.  Also flags whether the match was exact.
675     */
676    ir_function_signature *matching_signature(const exec_list *actual_param,
677 					     bool *match_is_exact);
678 
679    /**
680     * Find a signature that matches a set of actual parameters, taking implicit
681     * conversions into account.
682     */
683    ir_function_signature *matching_signature(const exec_list *actual_param);
684 
685    /**
686     * Find a signature that exactly matches a set of actual parameters without
687     * any implicit type conversions.
688     */
689    ir_function_signature *exact_matching_signature(const exec_list *actual_ps);
690 
691    /**
692     * Name of the function.
693     */
694    const char *name;
695 
696    /** Whether or not this function has a signature that isn't a built-in. */
697    bool has_user_signature();
698 
699    /**
700     * List of ir_function_signature for each overloaded function with this name.
701     */
702    struct exec_list signatures;
703 };
704 
function_name()705 inline const char *ir_function_signature::function_name() const
706 {
707    return this->_function->name;
708 }
709 /*@}*/
710 
711 
712 /**
713  * IR instruction representing high-level if-statements
714  */
715 class ir_if : public ir_instruction {
716 public:
ir_if(ir_rvalue * condition)717    ir_if(ir_rvalue *condition)
718       : condition(condition)
719    {
720       ir_type = ir_type_if;
721    }
722 
723    virtual ir_if *clone(void *mem_ctx, struct hash_table *ht) const;
724 
as_if()725    virtual ir_if *as_if()
726    {
727       return this;
728    }
729 
accept(ir_visitor * v)730    virtual void accept(ir_visitor *v)
731    {
732       v->visit(this);
733    }
734 
735    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
736 
737    ir_rvalue *condition;
738    /** List of ir_instruction for the body of the then branch */
739    exec_list  then_instructions;
740    /** List of ir_instruction for the body of the else branch */
741    exec_list  else_instructions;
742 };
743 
744 
745 /**
746  * IR instruction representing a high-level loop structure.
747  */
748 class ir_loop : public ir_instruction {
749 public:
750    ir_loop();
751 
752    virtual ir_loop *clone(void *mem_ctx, struct hash_table *ht) const;
753 
accept(ir_visitor * v)754    virtual void accept(ir_visitor *v)
755    {
756       v->visit(this);
757    }
758 
759    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
760 
as_loop()761    virtual ir_loop *as_loop()
762    {
763       return this;
764    }
765 
766    /**
767     * Get an iterator for the instructions of the loop body
768     */
iterator()769    exec_list_iterator iterator()
770    {
771       return body_instructions.iterator();
772    }
773 
774    /** List of ir_instruction that make up the body of the loop. */
775    exec_list body_instructions;
776 
777    /**
778     * \name Loop counter and controls
779     *
780     * Represents a loop like a FORTRAN \c do-loop.
781     *
782     * \note
783     * If \c from and \c to are the same value, the loop will execute once.
784     */
785    /*@{*/
786    ir_rvalue *from;             /** Value of the loop counter on the first
787 				 * iteration of the loop.
788 				 */
789    ir_rvalue *to;               /** Value of the loop counter on the last
790 				 * iteration of the loop.
791 				 */
792    ir_rvalue *increment;
793    ir_variable *counter;
794 
795    /**
796     * Comparison operation in the loop terminator.
797     *
798     * If any of the loop control fields are non-\c NULL, this field must be
799     * one of \c ir_binop_less, \c ir_binop_greater, \c ir_binop_lequal,
800     * \c ir_binop_gequal, \c ir_binop_equal, or \c ir_binop_nequal.
801     */
802    int cmp;
803    /*@}*/
804 };
805 
806 
807 class ir_assignment : public ir_instruction {
808 public:
809    ir_assignment(ir_rvalue *lhs, ir_rvalue *rhs, ir_rvalue *condition = NULL);
810 
811    /**
812     * Construct an assignment with an explicit write mask
813     *
814     * \note
815     * Since a write mask is supplied, the LHS must already be a bare
816     * \c ir_dereference.  The cannot be any swizzles in the LHS.
817     */
818    ir_assignment(ir_dereference *lhs, ir_rvalue *rhs, ir_rvalue *condition,
819 		 unsigned write_mask);
820 
821    virtual ir_assignment *clone(void *mem_ctx, struct hash_table *ht) const;
822 
823    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
824 
accept(ir_visitor * v)825    virtual void accept(ir_visitor *v)
826    {
827       v->visit(this);
828    }
829 
830    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
831 
as_assignment()832    virtual ir_assignment * as_assignment()
833    {
834       return this;
835    }
836 
837    /**
838     * Get a whole variable written by an assignment
839     *
840     * If the LHS of the assignment writes a whole variable, the variable is
841     * returned.  Otherwise \c NULL is returned.  Examples of whole-variable
842     * assignment are:
843     *
844     *  - Assigning to a scalar
845     *  - Assigning to all components of a vector
846     *  - Whole array (or matrix) assignment
847     *  - Whole structure assignment
848     */
849    ir_variable *whole_variable_written();
850 
851    /**
852     * Set the LHS of an assignment
853     */
854    void set_lhs(ir_rvalue *lhs);
855 
856    /**
857     * Left-hand side of the assignment.
858     *
859     * This should be treated as read only.  If you need to set the LHS of an
860     * assignment, use \c ir_assignment::set_lhs.
861     */
862    ir_dereference *lhs;
863 
864    /**
865     * Value being assigned
866     */
867    ir_rvalue *rhs;
868 
869    /**
870     * Optional condition for the assignment.
871     */
872    ir_rvalue *condition;
873 
874 
875    /**
876     * Component mask written
877     *
878     * For non-vector types in the LHS, this field will be zero.  For vector
879     * types, a bit will be set for each component that is written.  Note that
880     * for \c vec2 and \c vec3 types only the lower bits will ever be set.
881     *
882     * A partially-set write mask means that each enabled channel gets
883     * the value from a consecutive channel of the rhs.  For example,
884     * to write just .xyw of gl_FrontColor with color:
885     *
886     * (assign (constant bool (1)) (xyw)
887     *     (var_ref gl_FragColor)
888     *     (swiz xyw (var_ref color)))
889     */
890    unsigned write_mask:4;
891 };
892 
893 /* Update ir_expression::num_operands() and operator_strs when
894  * updating this list.
895  */
896 enum ir_expression_operation {
897    ir_unop_bit_not,
898    ir_unop_logic_not,
899    ir_unop_neg,
900    ir_unop_abs,
901    ir_unop_sign,
902    ir_unop_rcp,
903    ir_unop_rsq,
904    ir_unop_sqrt,
905    ir_unop_exp,         /**< Log base e on gentype */
906    ir_unop_log,	        /**< Natural log on gentype */
907    ir_unop_exp2,
908    ir_unop_log2,
909    ir_unop_f2i,         /**< Float-to-integer conversion. */
910    ir_unop_f2u,         /**< Float-to-unsigned conversion. */
911    ir_unop_i2f,         /**< Integer-to-float conversion. */
912    ir_unop_f2b,         /**< Float-to-boolean conversion */
913    ir_unop_b2f,         /**< Boolean-to-float conversion */
914    ir_unop_i2b,         /**< int-to-boolean conversion */
915    ir_unop_b2i,         /**< Boolean-to-int conversion */
916    ir_unop_u2f,         /**< Unsigned-to-float conversion. */
917    ir_unop_i2u,         /**< Integer-to-unsigned conversion. */
918    ir_unop_u2i,         /**< Unsigned-to-integer conversion. */
919    ir_unop_bitcast_i2f, /**< Bit-identical int-to-float "conversion" */
920    ir_unop_bitcast_f2i, /**< Bit-identical float-to-int "conversion" */
921    ir_unop_bitcast_u2f, /**< Bit-identical uint-to-float "conversion" */
922    ir_unop_bitcast_f2u, /**< Bit-identical float-to-uint "conversion" */
923    ir_unop_any,
924 
925    /**
926     * \name Unary floating-point rounding operations.
927     */
928    /*@{*/
929    ir_unop_trunc,
930    ir_unop_ceil,
931    ir_unop_floor,
932    ir_unop_fract,
933    ir_unop_round_even,
934    /*@}*/
935 
936    /**
937     * \name Trigonometric operations.
938     */
939    /*@{*/
940    ir_unop_sin,
941    ir_unop_cos,
942    ir_unop_sin_reduced,    /**< Reduced range sin. [-pi, pi] */
943    ir_unop_cos_reduced,    /**< Reduced range cos. [-pi, pi] */
944    /*@}*/
945 
946    /**
947     * \name Partial derivatives.
948     */
949    /*@{*/
950    ir_unop_dFdx,
951    ir_unop_dFdy,
952    /*@}*/
953 
954    ir_unop_noise,
955 
956    /**
957     * A sentinel marking the last of the unary operations.
958     */
959    ir_last_unop = ir_unop_noise,
960 
961    ir_binop_add,
962    ir_binop_sub,
963    ir_binop_mul,
964    ir_binop_div,
965 
966    /**
967     * Takes one of two combinations of arguments:
968     *
969     * - mod(vecN, vecN)
970     * - mod(vecN, float)
971     *
972     * Does not take integer types.
973     */
974    ir_binop_mod,
975 
976    /**
977     * \name Binary comparison operators which return a boolean vector.
978     * The type of both operands must be equal.
979     */
980    /*@{*/
981    ir_binop_less,
982    ir_binop_greater,
983    ir_binop_lequal,
984    ir_binop_gequal,
985    ir_binop_equal,
986    ir_binop_nequal,
987    /**
988     * Returns single boolean for whether all components of operands[0]
989     * equal the components of operands[1].
990     */
991    ir_binop_all_equal,
992    /**
993     * Returns single boolean for whether any component of operands[0]
994     * is not equal to the corresponding component of operands[1].
995     */
996    ir_binop_any_nequal,
997    /*@}*/
998 
999    /**
1000     * \name Bit-wise binary operations.
1001     */
1002    /*@{*/
1003    ir_binop_lshift,
1004    ir_binop_rshift,
1005    ir_binop_bit_and,
1006    ir_binop_bit_xor,
1007    ir_binop_bit_or,
1008    /*@}*/
1009 
1010    ir_binop_logic_and,
1011    ir_binop_logic_xor,
1012    ir_binop_logic_or,
1013 
1014    ir_binop_dot,
1015    ir_binop_min,
1016    ir_binop_max,
1017 
1018    ir_binop_pow,
1019 
1020    /**
1021     * Load a value the size of a given GLSL type from a uniform block.
1022     *
1023     * operand0 is the ir_constant uniform block index in the linked shader.
1024     * operand1 is a byte offset within the uniform block.
1025     */
1026    ir_binop_ubo_load,
1027 
1028    /**
1029     * A sentinel marking the last of the binary operations.
1030     */
1031    ir_last_binop = ir_binop_ubo_load,
1032 
1033    ir_quadop_vector,
1034 
1035    /**
1036     * A sentinel marking the last of all operations.
1037     */
1038    ir_last_opcode = ir_quadop_vector
1039 };
1040 
1041 class ir_expression : public ir_rvalue {
1042 public:
1043    /**
1044     * Constructor for unary operation expressions
1045     */
1046    ir_expression(int op, const struct glsl_type *type, ir_rvalue *);
1047    ir_expression(int op, ir_rvalue *);
1048 
1049    /**
1050     * Constructor for binary operation expressions
1051     */
1052    ir_expression(int op, const struct glsl_type *type,
1053 		 ir_rvalue *, ir_rvalue *);
1054    ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1);
1055 
1056    /**
1057     * Constructor for quad operator expressions
1058     */
1059    ir_expression(int op, const struct glsl_type *type,
1060 		 ir_rvalue *, ir_rvalue *, ir_rvalue *, ir_rvalue *);
1061 
as_expression()1062    virtual ir_expression *as_expression()
1063    {
1064       return this;
1065    }
1066 
1067    virtual ir_expression *clone(void *mem_ctx, struct hash_table *ht) const;
1068 
1069    /**
1070     * Attempt to constant-fold the expression
1071     *
1072     * The "variable_context" hash table links ir_variable * to ir_constant *
1073     * that represent the variables' values.  \c NULL represents an empty
1074     * context.
1075     *
1076     * If the expression cannot be constant folded, this method will return
1077     * \c NULL.
1078     */
1079    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1080 
1081    /**
1082     * Determine the number of operands used by an expression
1083     */
1084    static unsigned int get_num_operands(ir_expression_operation);
1085 
1086    /**
1087     * Determine the number of operands used by an expression
1088     */
get_num_operands()1089    unsigned int get_num_operands() const
1090    {
1091       return (this->operation == ir_quadop_vector)
1092 	 ? this->type->vector_elements : get_num_operands(operation);
1093    }
1094 
1095    /**
1096     * Return a string representing this expression's operator.
1097     */
1098    const char *operator_string();
1099 
1100    /**
1101     * Return a string representing this expression's operator.
1102     */
1103    static const char *operator_string(ir_expression_operation);
1104 
1105 
1106    /**
1107     * Do a reverse-lookup to translate the given string into an operator.
1108     */
1109    static ir_expression_operation get_operator(const char *);
1110 
accept(ir_visitor * v)1111    virtual void accept(ir_visitor *v)
1112    {
1113       v->visit(this);
1114    }
1115 
1116    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1117 
1118    ir_expression_operation operation;
1119    ir_rvalue *operands[4];
1120 };
1121 
1122 
1123 /**
1124  * HIR instruction representing a high-level function call, containing a list
1125  * of parameters and returning a value in the supplied temporary.
1126  */
1127 class ir_call : public ir_instruction {
1128 public:
ir_call(ir_function_signature * callee,ir_dereference_variable * return_deref,exec_list * actual_parameters)1129    ir_call(ir_function_signature *callee,
1130 	   ir_dereference_variable *return_deref,
1131 	   exec_list *actual_parameters)
1132       : return_deref(return_deref), callee(callee)
1133    {
1134       ir_type = ir_type_call;
1135       assert(callee->return_type != NULL);
1136       actual_parameters->move_nodes_to(& this->actual_parameters);
1137       this->use_builtin = callee->is_builtin;
1138    }
1139 
1140    virtual ir_call *clone(void *mem_ctx, struct hash_table *ht) const;
1141 
1142    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1143 
as_call()1144    virtual ir_call *as_call()
1145    {
1146       return this;
1147    }
1148 
accept(ir_visitor * v)1149    virtual void accept(ir_visitor *v)
1150    {
1151       v->visit(this);
1152    }
1153 
1154    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1155 
1156    /**
1157     * Get an iterator for the set of acutal parameters
1158     */
iterator()1159    exec_list_iterator iterator()
1160    {
1161       return actual_parameters.iterator();
1162    }
1163 
1164    /**
1165     * Get the name of the function being called.
1166     */
callee_name()1167    const char *callee_name() const
1168    {
1169       return callee->function_name();
1170    }
1171 
1172    /**
1173     * Generates an inline version of the function before @ir,
1174     * storing the return value in return_deref.
1175     */
1176    void generate_inline(ir_instruction *ir);
1177 
1178    /**
1179     * Storage for the function's return value.
1180     * This must be NULL if the return type is void.
1181     */
1182    ir_dereference_variable *return_deref;
1183 
1184    /**
1185     * The specific function signature being called.
1186     */
1187    ir_function_signature *callee;
1188 
1189    /* List of ir_rvalue of paramaters passed in this call. */
1190    exec_list actual_parameters;
1191 
1192    /** Should this call only bind to a built-in function? */
1193    bool use_builtin;
1194 };
1195 
1196 
1197 /**
1198  * \name Jump-like IR instructions.
1199  *
1200  * These include \c break, \c continue, \c return, and \c discard.
1201  */
1202 /*@{*/
1203 class ir_jump : public ir_instruction {
1204 protected:
ir_jump()1205    ir_jump()
1206    {
1207       ir_type = ir_type_unset;
1208    }
1209 };
1210 
1211 class ir_return : public ir_jump {
1212 public:
ir_return()1213    ir_return()
1214       : value(NULL)
1215    {
1216       this->ir_type = ir_type_return;
1217    }
1218 
ir_return(ir_rvalue * value)1219    ir_return(ir_rvalue *value)
1220       : value(value)
1221    {
1222       this->ir_type = ir_type_return;
1223    }
1224 
1225    virtual ir_return *clone(void *mem_ctx, struct hash_table *) const;
1226 
as_return()1227    virtual ir_return *as_return()
1228    {
1229       return this;
1230    }
1231 
get_value()1232    ir_rvalue *get_value() const
1233    {
1234       return value;
1235    }
1236 
accept(ir_visitor * v)1237    virtual void accept(ir_visitor *v)
1238    {
1239       v->visit(this);
1240    }
1241 
1242    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1243 
1244    ir_rvalue *value;
1245 };
1246 
1247 
1248 /**
1249  * Jump instructions used inside loops
1250  *
1251  * These include \c break and \c continue.  The \c break within a loop is
1252  * different from the \c break within a switch-statement.
1253  *
1254  * \sa ir_switch_jump
1255  */
1256 class ir_loop_jump : public ir_jump {
1257 public:
1258    enum jump_mode {
1259       jump_break,
1260       jump_continue
1261    };
1262 
ir_loop_jump(jump_mode mode)1263    ir_loop_jump(jump_mode mode)
1264    {
1265       this->ir_type = ir_type_loop_jump;
1266       this->mode = mode;
1267    }
1268 
1269    virtual ir_loop_jump *clone(void *mem_ctx, struct hash_table *) const;
1270 
accept(ir_visitor * v)1271    virtual void accept(ir_visitor *v)
1272    {
1273       v->visit(this);
1274    }
1275 
1276    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1277 
is_break()1278    bool is_break() const
1279    {
1280       return mode == jump_break;
1281    }
1282 
is_continue()1283    bool is_continue() const
1284    {
1285       return mode == jump_continue;
1286    }
1287 
1288    /** Mode selector for the jump instruction. */
1289    enum jump_mode mode;
1290 };
1291 
1292 /**
1293  * IR instruction representing discard statements.
1294  */
1295 class ir_discard : public ir_jump {
1296 public:
ir_discard()1297    ir_discard()
1298    {
1299       this->ir_type = ir_type_discard;
1300       this->condition = NULL;
1301    }
1302 
ir_discard(ir_rvalue * cond)1303    ir_discard(ir_rvalue *cond)
1304    {
1305       this->ir_type = ir_type_discard;
1306       this->condition = cond;
1307    }
1308 
1309    virtual ir_discard *clone(void *mem_ctx, struct hash_table *ht) const;
1310 
accept(ir_visitor * v)1311    virtual void accept(ir_visitor *v)
1312    {
1313       v->visit(this);
1314    }
1315 
1316    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1317 
as_discard()1318    virtual ir_discard *as_discard()
1319    {
1320       return this;
1321    }
1322 
1323    ir_rvalue *condition;
1324 };
1325 /*@}*/
1326 
1327 
1328 /**
1329  * Texture sampling opcodes used in ir_texture
1330  */
1331 enum ir_texture_opcode {
1332    ir_tex,		/**< Regular texture look-up */
1333    ir_txb,		/**< Texture look-up with LOD bias */
1334    ir_txl,		/**< Texture look-up with explicit LOD */
1335    ir_txd,		/**< Texture look-up with partial derivatvies */
1336    ir_txf,		/**< Texel fetch with explicit LOD */
1337    ir_txs		/**< Texture size */
1338 };
1339 
1340 
1341 /**
1342  * IR instruction to sample a texture
1343  *
1344  * The specific form of the IR instruction depends on the \c mode value
1345  * selected from \c ir_texture_opcodes.  In the printed IR, these will
1346  * appear as:
1347  *
1348  *                                    Texel offset (0 or an expression)
1349  *                                    | Projection divisor
1350  *                                    | |  Shadow comparitor
1351  *                                    | |  |
1352  *                                    v v  v
1353  * (tex <type> <sampler> <coordinate> 0 1 ( ))
1354  * (txb <type> <sampler> <coordinate> 0 1 ( ) <bias>)
1355  * (txl <type> <sampler> <coordinate> 0 1 ( ) <lod>)
1356  * (txd <type> <sampler> <coordinate> 0 1 ( ) (dPdx dPdy))
1357  * (txf <type> <sampler> <coordinate> 0       <lod>)
1358  * (txs <type> <sampler> <lod>)
1359  */
1360 class ir_texture : public ir_rvalue {
1361 public:
ir_texture(enum ir_texture_opcode op)1362    ir_texture(enum ir_texture_opcode op)
1363       : op(op), coordinate(NULL), projector(NULL), shadow_comparitor(NULL),
1364         offset(NULL)
1365    {
1366       this->ir_type = ir_type_texture;
1367    }
1368 
1369    virtual ir_texture *clone(void *mem_ctx, struct hash_table *) const;
1370 
1371    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1372 
accept(ir_visitor * v)1373    virtual void accept(ir_visitor *v)
1374    {
1375       v->visit(this);
1376    }
1377 
1378    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1379 
1380    /**
1381     * Return a string representing the ir_texture_opcode.
1382     */
1383    const char *opcode_string();
1384 
1385    /** Set the sampler and type. */
1386    void set_sampler(ir_dereference *sampler, const glsl_type *type);
1387 
1388    /**
1389     * Do a reverse-lookup to translate a string into an ir_texture_opcode.
1390     */
1391    static ir_texture_opcode get_opcode(const char *);
1392 
1393    enum ir_texture_opcode op;
1394 
1395    /** Sampler to use for the texture access. */
1396    ir_dereference *sampler;
1397 
1398    /** Texture coordinate to sample */
1399    ir_rvalue *coordinate;
1400 
1401    /**
1402     * Value used for projective divide.
1403     *
1404     * If there is no projective divide (the common case), this will be
1405     * \c NULL.  Optimization passes should check for this to point to a constant
1406     * of 1.0 and replace that with \c NULL.
1407     */
1408    ir_rvalue *projector;
1409 
1410    /**
1411     * Coordinate used for comparison on shadow look-ups.
1412     *
1413     * If there is no shadow comparison, this will be \c NULL.  For the
1414     * \c ir_txf opcode, this *must* be \c NULL.
1415     */
1416    ir_rvalue *shadow_comparitor;
1417 
1418    /** Texel offset. */
1419    ir_rvalue *offset;
1420 
1421    union {
1422       ir_rvalue *lod;		/**< Floating point LOD */
1423       ir_rvalue *bias;		/**< Floating point LOD bias */
1424       struct {
1425 	 ir_rvalue *dPdx;	/**< Partial derivative of coordinate wrt X */
1426 	 ir_rvalue *dPdy;	/**< Partial derivative of coordinate wrt Y */
1427       } grad;
1428    } lod_info;
1429 };
1430 
1431 
1432 struct ir_swizzle_mask {
1433    unsigned x:2;
1434    unsigned y:2;
1435    unsigned z:2;
1436    unsigned w:2;
1437 
1438    /**
1439     * Number of components in the swizzle.
1440     */
1441    unsigned num_components:3;
1442 
1443    /**
1444     * Does the swizzle contain duplicate components?
1445     *
1446     * L-value swizzles cannot contain duplicate components.
1447     */
1448    unsigned has_duplicates:1;
1449 };
1450 
1451 
1452 class ir_swizzle : public ir_rvalue {
1453 public:
1454    ir_swizzle(ir_rvalue *, unsigned x, unsigned y, unsigned z, unsigned w,
1455               unsigned count);
1456 
1457    ir_swizzle(ir_rvalue *val, const unsigned *components, unsigned count);
1458 
1459    ir_swizzle(ir_rvalue *val, ir_swizzle_mask mask);
1460 
1461    virtual ir_swizzle *clone(void *mem_ctx, struct hash_table *) const;
1462 
1463    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1464 
as_swizzle()1465    virtual ir_swizzle *as_swizzle()
1466    {
1467       return this;
1468    }
1469 
1470    /**
1471     * Construct an ir_swizzle from the textual representation.  Can fail.
1472     */
1473    static ir_swizzle *create(ir_rvalue *, const char *, unsigned vector_length);
1474 
accept(ir_visitor * v)1475    virtual void accept(ir_visitor *v)
1476    {
1477       v->visit(this);
1478    }
1479 
1480    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1481 
is_lvalue()1482    bool is_lvalue() const
1483    {
1484       return val->is_lvalue() && !mask.has_duplicates;
1485    }
1486 
1487    /**
1488     * Get the variable that is ultimately referenced by an r-value
1489     */
1490    virtual ir_variable *variable_referenced() const;
1491 
1492    ir_rvalue *val;
1493    ir_swizzle_mask mask;
1494 
1495 private:
1496    /**
1497     * Initialize the mask component of a swizzle
1498     *
1499     * This is used by the \c ir_swizzle constructors.
1500     */
1501    void init_mask(const unsigned *components, unsigned count);
1502 };
1503 
1504 
1505 class ir_dereference : public ir_rvalue {
1506 public:
1507    virtual ir_dereference *clone(void *mem_ctx, struct hash_table *) const = 0;
1508 
as_dereference()1509    virtual ir_dereference *as_dereference()
1510    {
1511       return this;
1512    }
1513 
1514    bool is_lvalue() const;
1515 
1516    /**
1517     * Get the variable that is ultimately referenced by an r-value
1518     */
1519    virtual ir_variable *variable_referenced() const = 0;
1520 
1521    /**
1522     * Get the constant that is ultimately referenced by an r-value,
1523     * in a constant expression evaluation context.
1524     *
1525     * The offset is used when the reference is to a specific column of
1526     * a matrix.
1527     */
1528   virtual void constant_referenced(struct hash_table *variable_context, ir_constant *&store, int &offset) const = 0;
1529 };
1530 
1531 
1532 class ir_dereference_variable : public ir_dereference {
1533 public:
1534    ir_dereference_variable(ir_variable *var);
1535 
1536    virtual ir_dereference_variable *clone(void *mem_ctx,
1537 					  struct hash_table *) const;
1538 
1539    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1540 
as_dereference_variable()1541    virtual ir_dereference_variable *as_dereference_variable()
1542    {
1543       return this;
1544    }
1545 
1546    /**
1547     * Get the variable that is ultimately referenced by an r-value
1548     */
variable_referenced()1549    virtual ir_variable *variable_referenced() const
1550    {
1551       return this->var;
1552    }
1553 
1554    /**
1555     * Get the constant that is ultimately referenced by an r-value,
1556     * in a constant expression evaluation context.
1557     *
1558     * The offset is used when the reference is to a specific column of
1559     * a matrix.
1560     */
1561    virtual void constant_referenced(struct hash_table *variable_context, ir_constant *&store, int &offset) const;
1562 
whole_variable_referenced()1563    virtual ir_variable *whole_variable_referenced()
1564    {
1565       /* ir_dereference_variable objects always dereference the entire
1566        * variable.  However, if this dereference is dereferenced by anything
1567        * else, the complete deferefernce chain is not a whole-variable
1568        * dereference.  This method should only be called on the top most
1569        * ir_rvalue in a dereference chain.
1570        */
1571       return this->var;
1572    }
1573 
accept(ir_visitor * v)1574    virtual void accept(ir_visitor *v)
1575    {
1576       v->visit(this);
1577    }
1578 
1579    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1580 
1581    /**
1582     * Object being dereferenced.
1583     */
1584    ir_variable *var;
1585 };
1586 
1587 
1588 class ir_dereference_array : public ir_dereference {
1589 public:
1590    ir_dereference_array(ir_rvalue *value, ir_rvalue *array_index);
1591 
1592    ir_dereference_array(ir_variable *var, ir_rvalue *array_index);
1593 
1594    virtual ir_dereference_array *clone(void *mem_ctx,
1595 				       struct hash_table *) const;
1596 
1597    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1598 
as_dereference_array()1599    virtual ir_dereference_array *as_dereference_array()
1600    {
1601       return this;
1602    }
1603 
1604    /**
1605     * Get the variable that is ultimately referenced by an r-value
1606     */
variable_referenced()1607    virtual ir_variable *variable_referenced() const
1608    {
1609       return this->array->variable_referenced();
1610    }
1611 
1612    /**
1613     * Get the constant that is ultimately referenced by an r-value,
1614     * in a constant expression evaluation context.
1615     *
1616     * The offset is used when the reference is to a specific column of
1617     * a matrix.
1618     */
1619    virtual void constant_referenced(struct hash_table *variable_context, ir_constant *&store, int &offset) const;
1620 
accept(ir_visitor * v)1621    virtual void accept(ir_visitor *v)
1622    {
1623       v->visit(this);
1624    }
1625 
1626    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1627 
1628    ir_rvalue *array;
1629    ir_rvalue *array_index;
1630 
1631 private:
1632    void set_array(ir_rvalue *value);
1633 };
1634 
1635 
1636 class ir_dereference_record : public ir_dereference {
1637 public:
1638    ir_dereference_record(ir_rvalue *value, const char *field);
1639 
1640    ir_dereference_record(ir_variable *var, const char *field);
1641 
1642    virtual ir_dereference_record *clone(void *mem_ctx,
1643 					struct hash_table *) const;
1644 
1645    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1646 
1647    /**
1648     * Get the variable that is ultimately referenced by an r-value
1649     */
variable_referenced()1650    virtual ir_variable *variable_referenced() const
1651    {
1652       return this->record->variable_referenced();
1653    }
1654 
1655    /**
1656     * Get the constant that is ultimately referenced by an r-value,
1657     * in a constant expression evaluation context.
1658     *
1659     * The offset is used when the reference is to a specific column of
1660     * a matrix.
1661     */
1662    virtual void constant_referenced(struct hash_table *variable_context, ir_constant *&store, int &offset) const;
1663 
accept(ir_visitor * v)1664    virtual void accept(ir_visitor *v)
1665    {
1666       v->visit(this);
1667    }
1668 
1669    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1670 
1671    ir_rvalue *record;
1672    const char *field;
1673 };
1674 
1675 
1676 /**
1677  * Data stored in an ir_constant
1678  */
1679 union ir_constant_data {
1680       unsigned u[16];
1681       int i[16];
1682       float f[16];
1683       bool b[16];
1684 };
1685 
1686 
1687 class ir_constant : public ir_rvalue {
1688 public:
1689    ir_constant(const struct glsl_type *type, const ir_constant_data *data);
1690    ir_constant(bool b);
1691    ir_constant(unsigned int u);
1692    ir_constant(int i);
1693    ir_constant(float f);
1694 
1695    /**
1696     * Construct an ir_constant from a list of ir_constant values
1697     */
1698    ir_constant(const struct glsl_type *type, exec_list *values);
1699 
1700    /**
1701     * Construct an ir_constant from a scalar component of another ir_constant
1702     *
1703     * The new \c ir_constant inherits the type of the component from the
1704     * source constant.
1705     *
1706     * \note
1707     * In the case of a matrix constant, the new constant is a scalar, \b not
1708     * a vector.
1709     */
1710    ir_constant(const ir_constant *c, unsigned i);
1711 
1712    /**
1713     * Return a new ir_constant of the specified type containing all zeros.
1714     */
1715    static ir_constant *zero(void *mem_ctx, const glsl_type *type);
1716 
1717    virtual ir_constant *clone(void *mem_ctx, struct hash_table *) const;
1718 
1719    virtual ir_constant *constant_expression_value(struct hash_table *variable_context = NULL);
1720 
as_constant()1721    virtual ir_constant *as_constant()
1722    {
1723       return this;
1724    }
1725 
accept(ir_visitor * v)1726    virtual void accept(ir_visitor *v)
1727    {
1728       v->visit(this);
1729    }
1730 
1731    virtual ir_visitor_status accept(ir_hierarchical_visitor *);
1732 
1733    /**
1734     * Get a particular component of a constant as a specific type
1735     *
1736     * This is useful, for example, to get a value from an integer constant
1737     * as a float or bool.  This appears frequently when constructors are
1738     * called with all constant parameters.
1739     */
1740    /*@{*/
1741    bool get_bool_component(unsigned i) const;
1742    float get_float_component(unsigned i) const;
1743    int get_int_component(unsigned i) const;
1744    unsigned get_uint_component(unsigned i) const;
1745    /*@}*/
1746 
1747    ir_constant *get_array_element(unsigned i) const;
1748 
1749    ir_constant *get_record_field(const char *name);
1750 
1751    /**
1752     * Copy the values on another constant at a given offset.
1753     *
1754     * The offset is ignored for array or struct copies, it's only for
1755     * scalars or vectors into vectors or matrices.
1756     *
1757     * With identical types on both sides and zero offset it's clone()
1758     * without creating a new object.
1759     */
1760 
1761    void copy_offset(ir_constant *src, int offset);
1762 
1763    /**
1764     * Copy the values on another constant at a given offset and
1765     * following an assign-like mask.
1766     *
1767     * The mask is ignored for scalars.
1768     *
1769     * Note that this function only handles what assign can handle,
1770     * i.e. at most a vector as source and a column of a matrix as
1771     * destination.
1772     */
1773 
1774    void copy_masked_offset(ir_constant *src, int offset, unsigned int mask);
1775 
1776    /**
1777     * Determine whether a constant has the same value as another constant
1778     *
1779     * \sa ir_constant::is_zero, ir_constant::is_one,
1780     * ir_constant::is_negative_one, ir_constant::is_basis
1781     */
1782    bool has_value(const ir_constant *) const;
1783 
1784    virtual bool is_zero() const;
1785    virtual bool is_one() const;
1786    virtual bool is_negative_one() const;
1787    virtual bool is_basis() const;
1788 
1789    /**
1790     * Value of the constant.
1791     *
1792     * The field used to back the values supplied by the constant is determined
1793     * by the type associated with the \c ir_instruction.  Constants may be
1794     * scalars, vectors, or matrices.
1795     */
1796    union ir_constant_data value;
1797 
1798    /* Array elements */
1799    ir_constant **array_elements;
1800 
1801    /* Structure fields */
1802    exec_list components;
1803 
1804 private:
1805    /**
1806     * Parameterless constructor only used by the clone method
1807     */
1808    ir_constant(void);
1809 };
1810 
1811 /*@}*/
1812 
1813 /**
1814  * Apply a visitor to each IR node in a list
1815  */
1816 void
1817 visit_exec_list(exec_list *list, ir_visitor *visitor);
1818 
1819 /**
1820  * Validate invariants on each IR node in a list
1821  */
1822 void validate_ir_tree(exec_list *instructions);
1823 
1824 struct _mesa_glsl_parse_state;
1825 struct gl_shader_program;
1826 
1827 /**
1828  * Detect whether an unlinked shader contains static recursion
1829  *
1830  * If the list of instructions is determined to contain static recursion,
1831  * \c _mesa_glsl_error will be called to emit error messages for each function
1832  * that is in the recursion cycle.
1833  */
1834 void
1835 detect_recursion_unlinked(struct _mesa_glsl_parse_state *state,
1836 			  exec_list *instructions);
1837 
1838 /**
1839  * Detect whether a linked shader contains static recursion
1840  *
1841  * If the list of instructions is determined to contain static recursion,
1842  * \c link_error_printf will be called to emit error messages for each function
1843  * that is in the recursion cycle.  In addition,
1844  * \c gl_shader_program::LinkStatus will be set to false.
1845  */
1846 void
1847 detect_recursion_linked(struct gl_shader_program *prog,
1848 			exec_list *instructions);
1849 
1850 /**
1851  * Make a clone of each IR instruction in a list
1852  *
1853  * \param in   List of IR instructions that are to be cloned
1854  * \param out  List to hold the cloned instructions
1855  */
1856 void
1857 clone_ir_list(void *mem_ctx, exec_list *out, const exec_list *in);
1858 
1859 extern void
1860 _mesa_glsl_initialize_variables(exec_list *instructions,
1861 				struct _mesa_glsl_parse_state *state);
1862 
1863 extern void
1864 _mesa_glsl_initialize_functions(_mesa_glsl_parse_state *state);
1865 
1866 extern void
1867 _mesa_glsl_release_functions(void);
1868 
1869 extern void
1870 reparent_ir(exec_list *list, void *mem_ctx);
1871 
1872 struct glsl_symbol_table;
1873 
1874 extern void
1875 import_prototypes(const exec_list *source, exec_list *dest,
1876 		  struct glsl_symbol_table *symbols, void *mem_ctx);
1877 
1878 extern bool
1879 ir_has_call(ir_instruction *ir);
1880 
1881 extern void
1882 do_set_program_inouts(exec_list *instructions, struct gl_program *prog,
1883                       bool is_fragment_shader);
1884 
1885 extern char *
1886 prototype_string(const glsl_type *return_type, const char *name,
1887 		 exec_list *parameters);
1888 
1889 #endif /* IR_H */
1890