xref: /netbsd-src/external/gpl3/gcc.old/dist/gcc/config/riscv/riscv-builtins.c (revision d90047b5d07facf36e6c01dcc0bded8997ce9cc2)
1 /* Subroutines used for expanding RISC-V builtins.
2    Copyright (C) 2011-2017 Free Software Foundation, Inc.
3    Contributed by Andrew Waterman (andrew@sifive.com).
4 
5 This file is part of GCC.
6 
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11 
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3.  If not see
19 <http://www.gnu.org/licenses/>.  */
20 
21 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "tm.h"
25 #include "rtl.h"
26 #include "tree.h"
27 #include "gimple-expr.h"
28 #include "memmodel.h"
29 #include "expmed.h"
30 #include "optabs.h"
31 #include "recog.h"
32 #include "diagnostic-core.h"
33 #include "stor-layout.h"
34 #include "expr.h"
35 #include "langhooks.h"
36 
37 /* Macros to create an enumeration identifier for a function prototype.  */
38 #define RISCV_FTYPE_NAME1(A, B) RISCV_##A##_FTYPE_##B
39 
40 /* Classifies the prototype of a built-in function.  */
41 enum riscv_function_type {
42 #define DEF_RISCV_FTYPE(NARGS, LIST) RISCV_FTYPE_NAME##NARGS LIST,
43 #include "config/riscv/riscv-ftypes.def"
44 #undef DEF_RISCV_FTYPE
45   RISCV_MAX_FTYPE_MAX
46 };
47 
48 /* Specifies how a built-in function should be converted into rtl.  */
49 enum riscv_builtin_type {
50   /* The function corresponds directly to an .md pattern.  */
51   RISCV_BUILTIN_DIRECT,
52 
53   /* Likewise, but with return type VOID.  */
54   RISCV_BUILTIN_DIRECT_NO_TARGET
55 };
56 
57 /* Declare an availability predicate for built-in functions.  */
58 #define AVAIL(NAME, COND)		\
59  static unsigned int			\
60  riscv_builtin_avail_##NAME (void)	\
61  {					\
62    return (COND);			\
63  }
64 
65 /* This structure describes a single built-in function.  */
66 struct riscv_builtin_description {
67   /* The code of the main .md file instruction.  See riscv_builtin_type
68      for more information.  */
69   enum insn_code icode;
70 
71   /* The name of the built-in function.  */
72   const char *name;
73 
74   /* Specifies how the function should be expanded.  */
75   enum riscv_builtin_type builtin_type;
76 
77   /* The function's prototype.  */
78   enum riscv_function_type prototype;
79 
80   /* Whether the function is available.  */
81   unsigned int (*avail) (void);
82 };
83 
84 AVAIL (hard_float, TARGET_HARD_FLOAT)
85 
86 /* Construct a riscv_builtin_description from the given arguments.
87 
88    INSN is the name of the associated instruction pattern, without the
89    leading CODE_FOR_riscv_.
90 
91    NAME is the name of the function itself, without the leading
92    "__builtin_riscv_".
93 
94    BUILTIN_TYPE and FUNCTION_TYPE are riscv_builtin_description fields.
95 
96    AVAIL is the name of the availability predicate, without the leading
97    riscv_builtin_avail_.  */
98 #define RISCV_BUILTIN(INSN, NAME, BUILTIN_TYPE,	FUNCTION_TYPE, AVAIL)	\
99   { CODE_FOR_riscv_ ## INSN, "__builtin_riscv_" NAME,			\
100     BUILTIN_TYPE, FUNCTION_TYPE, riscv_builtin_avail_ ## AVAIL }
101 
102 /* Define __builtin_riscv_<INSN>, which is a RISCV_BUILTIN_DIRECT function
103    mapped to instruction CODE_FOR_riscv_<INSN>,  FUNCTION_TYPE and AVAIL
104    are as for RISCV_BUILTIN.  */
105 #define DIRECT_BUILTIN(INSN, FUNCTION_TYPE, AVAIL)			\
106   RISCV_BUILTIN (INSN, #INSN, RISCV_BUILTIN_DIRECT, FUNCTION_TYPE, AVAIL)
107 
108 /* Define __builtin_riscv_<INSN>, which is a RISCV_BUILTIN_DIRECT_NO_TARGET
109    function mapped to instruction CODE_FOR_riscv_<INSN>,  FUNCTION_TYPE
110    and AVAIL are as for RISCV_BUILTIN.  */
111 #define DIRECT_NO_TARGET_BUILTIN(INSN, FUNCTION_TYPE, AVAIL)		\
112   RISCV_BUILTIN (INSN, #INSN, RISCV_BUILTIN_DIRECT_NO_TARGET,		\
113 		FUNCTION_TYPE, AVAIL)
114 
115 /* Argument types.  */
116 #define RISCV_ATYPE_VOID void_type_node
117 #define RISCV_ATYPE_USI unsigned_intSI_type_node
118 
119 /* RISCV_FTYPE_ATYPESN takes N RISCV_FTYPES-like type codes and lists
120    their associated RISCV_ATYPEs.  */
121 #define RISCV_FTYPE_ATYPES1(A, B) \
122   RISCV_ATYPE_##A, RISCV_ATYPE_##B
123 
124 static const struct riscv_builtin_description riscv_builtins[] = {
125   DIRECT_BUILTIN (frflags, RISCV_USI_FTYPE_VOID, hard_float),
126   DIRECT_NO_TARGET_BUILTIN (fsflags, RISCV_VOID_FTYPE_USI, hard_float)
127 };
128 
129 /* Index I is the function declaration for riscv_builtins[I], or null if the
130    function isn't defined on this target.  */
131 static GTY(()) tree riscv_builtin_decls[ARRAY_SIZE (riscv_builtins)];
132 
133 /* Get the index I of the function declaration for riscv_builtin_decls[I]
134    using the instruction code or return null if not defined for the target.  */
135 static GTY(()) int riscv_builtin_decl_index[NUM_INSN_CODES];
136 
137 #define GET_BUILTIN_DECL(CODE) \
138   riscv_builtin_decls[riscv_builtin_decl_index[(CODE)]]
139 
140 /* Return the function type associated with function prototype TYPE.  */
141 
142 static tree
143 riscv_build_function_type (enum riscv_function_type type)
144 {
145   static tree types[(int) RISCV_MAX_FTYPE_MAX];
146 
147   if (types[(int) type] == NULL_TREE)
148     switch (type)
149       {
150 #define DEF_RISCV_FTYPE(NUM, ARGS)					\
151   case RISCV_FTYPE_NAME##NUM ARGS:					\
152     types[(int) type]							\
153       = build_function_type_list (RISCV_FTYPE_ATYPES##NUM ARGS,		\
154 				  NULL_TREE);				\
155     break;
156 #include "config/riscv/riscv-ftypes.def"
157 #undef DEF_RISCV_FTYPE
158       default:
159 	gcc_unreachable ();
160       }
161 
162   return types[(int) type];
163 }
164 
165 /* Implement TARGET_INIT_BUILTINS.  */
166 
167 void
168 riscv_init_builtins (void)
169 {
170   for (size_t i = 0; i < ARRAY_SIZE (riscv_builtins); i++)
171     {
172       const struct riscv_builtin_description *d = &riscv_builtins[i];
173       if (d->avail ())
174 	{
175 	  tree type = riscv_build_function_type (d->prototype);
176 	  riscv_builtin_decls[i]
177 	    = add_builtin_function (d->name, type, i, BUILT_IN_MD, NULL, NULL);
178 	  riscv_builtin_decl_index[d->icode] = i;
179 	}
180     }
181 }
182 
183 /* Implement TARGET_BUILTIN_DECL.  */
184 
185 tree
186 riscv_builtin_decl (unsigned int code, bool initialize_p ATTRIBUTE_UNUSED)
187 {
188   if (code >= ARRAY_SIZE (riscv_builtins))
189     return error_mark_node;
190   return riscv_builtin_decls[code];
191 }
192 
193 /* Take argument ARGNO from EXP's argument list and convert it into
194    an expand operand.  Store the operand in *OP.  */
195 
196 static void
197 riscv_prepare_builtin_arg (struct expand_operand *op, tree exp, unsigned argno)
198 {
199   tree arg = CALL_EXPR_ARG (exp, argno);
200   create_input_operand (op, expand_normal (arg), TYPE_MODE (TREE_TYPE (arg)));
201 }
202 
203 /* Expand instruction ICODE as part of a built-in function sequence.
204    Use the first NOPS elements of OPS as the instruction's operands.
205    HAS_TARGET_P is true if operand 0 is a target; it is false if the
206    instruction has no target.
207 
208    Return the target rtx if HAS_TARGET_P, otherwise return const0_rtx.  */
209 
210 static rtx
211 riscv_expand_builtin_insn (enum insn_code icode, unsigned int n_ops,
212 			   struct expand_operand *ops, bool has_target_p)
213 {
214   if (!maybe_expand_insn (icode, n_ops, ops))
215     {
216       error ("invalid argument to built-in function");
217       return has_target_p ? gen_reg_rtx (ops[0].mode) : const0_rtx;
218     }
219 
220   return has_target_p ? ops[0].value : const0_rtx;
221 }
222 
223 /* Expand a RISCV_BUILTIN_DIRECT or RISCV_BUILTIN_DIRECT_NO_TARGET function;
224    HAS_TARGET_P says which.  EXP is the CALL_EXPR that calls the function
225    and ICODE is the code of the associated .md pattern.  TARGET, if nonnull,
226    suggests a good place to put the result.  */
227 
228 static rtx
229 riscv_expand_builtin_direct (enum insn_code icode, rtx target, tree exp,
230 			     bool has_target_p)
231 {
232   struct expand_operand ops[MAX_RECOG_OPERANDS];
233 
234   /* Map any target to operand 0.  */
235   int opno = 0;
236   if (has_target_p)
237     create_output_operand (&ops[opno++], target, TYPE_MODE (TREE_TYPE (exp)));
238 
239   /* Map the arguments to the other operands.  */
240   gcc_assert (opno + call_expr_nargs (exp)
241 	      == insn_data[icode].n_generator_args);
242   for (int argno = 0; argno < call_expr_nargs (exp); argno++)
243     riscv_prepare_builtin_arg (&ops[opno++], exp, argno);
244 
245   return riscv_expand_builtin_insn (icode, opno, ops, has_target_p);
246 }
247 
248 /* Implement TARGET_EXPAND_BUILTIN.  */
249 
250 rtx
251 riscv_expand_builtin (tree exp, rtx target, rtx subtarget ATTRIBUTE_UNUSED,
252 		      machine_mode mode ATTRIBUTE_UNUSED,
253 		      int ignore ATTRIBUTE_UNUSED)
254 {
255   tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0);
256   unsigned int fcode = DECL_FUNCTION_CODE (fndecl);
257   const struct riscv_builtin_description *d = &riscv_builtins[fcode];
258 
259   switch (d->builtin_type)
260     {
261     case RISCV_BUILTIN_DIRECT:
262       return riscv_expand_builtin_direct (d->icode, target, exp, true);
263 
264     case RISCV_BUILTIN_DIRECT_NO_TARGET:
265       return riscv_expand_builtin_direct (d->icode, target, exp, false);
266     }
267 
268   gcc_unreachable ();
269 }
270 
271 /* Implement TARGET_ATOMIC_ASSIGN_EXPAND_FENV.  */
272 
273 void
274 riscv_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
275 {
276   if (!TARGET_HARD_FLOAT)
277     return;
278 
279   tree frflags = GET_BUILTIN_DECL (CODE_FOR_riscv_frflags);
280   tree fsflags = GET_BUILTIN_DECL (CODE_FOR_riscv_fsflags);
281   tree old_flags = create_tmp_var_raw (RISCV_ATYPE_USI);
282 
283   *hold = build2 (MODIFY_EXPR, RISCV_ATYPE_USI, old_flags,
284 		  build_call_expr (frflags, 0));
285   *clear = build_call_expr (fsflags, 1, old_flags);
286   *update = NULL_TREE;
287 }
288