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1 : : // Copyright (C) 2020-2025 Free Software Foundation, Inc.
2 : :
3 : : // This file is part of GCC.
4 : :
5 : : // GCC is free software; you can redistribute it and/or modify it under
6 : : // the terms of the GNU General Public License as published by the Free
7 : : // Software Foundation; either version 3, or (at your option) any later
8 : : // version.
9 : :
10 : : // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
11 : : // WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 : : // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 : : // for more details.
14 : :
15 : : // You should have received a copy of the GNU General Public License
16 : : // along with GCC; see the file COPYING3. If not see
17 : : // <http://www.gnu.org/licenses/>.
18 : :
19 : : #ifndef RUST_BACKEND_H
20 : : #define RUST_BACKEND_H
21 : :
22 : : #include <gmp.h>
23 : : #include <mpfr.h>
24 : : #include <mpc.h>
25 : :
26 : : #include "rust-location.h"
27 : : #include "rust-linemap.h"
28 : : #include "rust-diagnostics.h"
29 : : #include "util/rust-operators.h"
30 : : #include "util/rust-ggc.h"
31 : : #include "util/optional.h"
32 : : #include "tree.h"
33 : : #include "rust-gcc.h"
34 : :
35 : : // Pointers to these types are created by the backend, passed to the
36 : : // frontend, and passed back to the backend. The types must be
37 : : // defined by the backend using these names.
38 : :
39 : : // The backend representation of a variable.
40 : : class Bvariable;
41 : :
42 : : // The backend interface. This is a pure abstract class that a
43 : : // specific backend will implement.
44 : :
45 : : namespace Backend {
46 : :
47 : : namespace GGC {
48 : :
49 : : using Rust::GGC::Ident;
50 : :
51 : : } // namespace GGC
52 : :
53 : : void init ();
54 : :
55 : : // Name/type/location. Used for function parameters, struct fields,
56 : : // interface methods.
57 : : struct typed_identifier
58 : : {
59 : : GGC::Ident name;
60 : : tree type;
61 : : location_t location;
62 : :
63 : 148061 : typed_identifier (GGC::Ident a_name, tree a_type, location_t a_location)
64 : 140125 : : name (a_name), type (a_type), location (a_location)
65 : : {}
66 : : };
67 : :
68 : : // debug
69 : : void debug (tree);
70 : : void debug (Bvariable *);
71 : :
72 : : tree get_identifier_node (const std::string &str);
73 : :
74 : : // Types.
75 : :
76 : : // Get the wchar type
77 : : tree wchar_type ();
78 : :
79 : : // Get the Host pointer size in bits
80 : : int get_pointer_size ();
81 : :
82 : : // Get the raw str type const char*
83 : : tree raw_str_type ();
84 : :
85 : : // Get an unnamed integer type with the given signedness and number
86 : : // of bits.
87 : : tree integer_type (bool is_unsigned, int bits);
88 : :
89 : : // Get an unnamed floating point type with the given number of bits
90 : : // (32 or 64).
91 : : tree float_type (int bits);
92 : :
93 : : // Get a pointer type.
94 : : tree pointer_type (tree to_type);
95 : :
96 : : // Get a reference type.
97 : : tree reference_type (tree to_type);
98 : :
99 : : // make type immutable
100 : : tree immutable_type (tree base);
101 : :
102 : : // Get a function type. The receiver, parameter, and results are
103 : : // generated from the types in the Function_type. The Function_type
104 : : // is provided so that the names are available. This should return
105 : : // not the type of a Go function (which is a pointer to a struct)
106 : : // but the type of a C function pointer (which will be used as the
107 : : // type of the first field of the struct). If there is more than
108 : : // one result, RESULT_STRUCT is a struct type to hold the results,
109 : : // and RESULTS may be ignored; if there are zero or one results,
110 : : // RESULT_STRUCT is NULL.
111 : : tree function_type (const typed_identifier &receiver,
112 : : const std::vector<typed_identifier> ¶meters,
113 : : const std::vector<typed_identifier> &results,
114 : : tree result_struct, location_t location);
115 : :
116 : : tree function_type_variadic (const typed_identifier &receiver,
117 : : const std::vector<typed_identifier> ¶meters,
118 : : const std::vector<typed_identifier> &results,
119 : : tree result_struct, location_t location);
120 : :
121 : : tree function_ptr_type (tree result, const std::vector<tree> &praameters,
122 : : location_t location);
123 : :
124 : : // Get a struct type.
125 : : tree struct_type (const std::vector<typed_identifier> &fields,
126 : : bool layout = true);
127 : :
128 : : // Get a union type.
129 : : tree union_type (const std::vector<typed_identifier> &fields,
130 : : bool layout = true);
131 : :
132 : : // Get an array type.
133 : : tree array_type (tree element_type, tree length);
134 : :
135 : : // Return a named version of a type. The location is the location
136 : : // of the type definition. This will not be called for a type
137 : : // created via placeholder_pointer_type, placeholder_struct_type, or
138 : : // placeholder_array_type.. (It may be called for a pointer,
139 : : // struct, or array type in a case like "type P *byte; type Q P".)
140 : : tree named_type (GGC::Ident name, tree, location_t);
141 : :
142 : : // Return the size of a type.
143 : : int64_t type_size (tree);
144 : :
145 : : // Return the alignment of a type.
146 : : int64_t type_alignment (tree);
147 : :
148 : : // Return the alignment of a struct field of this type. This is
149 : : // normally the same as type_alignment, but not always.
150 : : int64_t type_field_alignment (tree);
151 : :
152 : : // Return the offset of field INDEX in a struct type. INDEX is the
153 : : // entry in the FIELDS std::vector parameter of struct_type or
154 : : // set_placeholder_struct_type.
155 : : int64_t type_field_offset (tree, size_t index);
156 : :
157 : : // Expressions.
158 : :
159 : : // Return an expression for a zero value of the given type. This is
160 : : // used for cases such as local variable initialization and
161 : : // converting nil to other types.
162 : : tree zero_expression (tree);
163 : :
164 : : // Create a reference to a variable.
165 : : tree var_expression (Bvariable *var, location_t);
166 : :
167 : : // Return an expression for the floating point value VAL in BTYPE.
168 : : tree float_constant_expression (tree btype, mpfr_t val);
169 : :
170 : : // Return an expression for the string value VAL.
171 : : tree string_constant_expression (const std::string &val);
172 : :
173 : : // Get a char literal
174 : : tree char_constant_expression (char c);
175 : :
176 : : // Get a char literal
177 : : tree wchar_constant_expression (wchar_t c);
178 : :
179 : : // Get a size literal
180 : : tree size_constant_expression (size_t val);
181 : :
182 : : // Return an expression for the boolean value VAL.
183 : : tree boolean_constant_expression (bool val);
184 : :
185 : : // Return an expression that converts EXPR to TYPE.
186 : : tree convert_expression (tree type, tree expr, location_t);
187 : :
188 : : // Return an expression for the field at INDEX in BSTRUCT.
189 : : tree struct_field_expression (tree bstruct, size_t index, location_t);
190 : :
191 : : // Create an expression that executes BSTAT before BEXPR.
192 : : tree compound_expression (tree bstat, tree bexpr, location_t);
193 : :
194 : : // Return an expression that executes THEN_EXPR if CONDITION is true, or
195 : : // ELSE_EXPR otherwise and returns the result as type BTYPE, within the
196 : : // specified function FUNCTION. ELSE_EXPR may be NULL. BTYPE may be NULL.
197 : : tree conditional_expression (tree function, tree btype, tree condition,
198 : : tree then_expr, tree else_expr, location_t);
199 : :
200 : : // Return an expression for the negation operation OP EXPR.
201 : : // Supported values of OP are enumerated in NegationOperator.
202 : : tree negation_expression (NegationOperator op, tree expr, location_t);
203 : :
204 : : // Return an expression for the operation LEFT OP RIGHT.
205 : : // Supported values of OP are enumerated in ArithmeticOrLogicalOperator.
206 : : tree arithmetic_or_logical_expression (ArithmeticOrLogicalOperator op,
207 : : tree left, tree right, location_t loc);
208 : :
209 : : // Return an expression for the operation LEFT OP RIGHT.
210 : : // Supported values of OP are enumerated in ArithmeticOrLogicalOperator.
211 : : // This function adds overflow checking and returns a list of statements to
212 : : // add to the current function context. The `receiver` variable refers to the
213 : : // variable which will contain the result of that operation.
214 : : tree arithmetic_or_logical_expression_checked (ArithmeticOrLogicalOperator op,
215 : : tree left, tree right,
216 : : location_t loc,
217 : : Bvariable *receiver);
218 : :
219 : : // Return an expression for the operation LEFT OP RIGHT.
220 : : // Supported values of OP are enumerated in ComparisonOperator.
221 : : tree comparison_expression (ComparisonOperator op, tree left, tree right,
222 : : location_t loc);
223 : :
224 : : // Return an expression for the operation LEFT OP RIGHT.
225 : : // Supported values of OP are enumerated in LazyBooleanOperator.
226 : : tree lazy_boolean_expression (LazyBooleanOperator op, tree left, tree right,
227 : : location_t);
228 : :
229 : : // Return an expression that constructs BTYPE with VALS. BTYPE must be the
230 : : // backend representation a of struct. VALS must be in the same order as the
231 : : // corresponding fields in BTYPE.
232 : : tree constructor_expression (tree btype, bool is_variant,
233 : : const std::vector<tree> &vals, int, location_t);
234 : :
235 : : // Return an expression that constructs an array of BTYPE with INDEXES and
236 : : // VALS. INDEXES and VALS must have the same amount of elements. Each index
237 : : // in INDEXES must be in the same order as the corresponding value in VALS.
238 : : tree array_constructor_expression (tree btype,
239 : : const std::vector<unsigned long> &indexes,
240 : : const std::vector<tree> &vals, location_t);
241 : :
242 : : tree array_initializer (tree, tree, tree, tree, tree, tree *, location_t);
243 : :
244 : : // Return an expression for ARRAY[INDEX] as an l-value. ARRAY is a valid
245 : : // fixed-length array, not a slice.
246 : : tree array_index_expression (tree array, tree index, location_t);
247 : :
248 : : // Return an expresison for SLICE[INDEX] as an l-value. SLICE is represented
249 : : // with a DST.
250 : : tree slice_index_expression (tree slice, tree index, location_t);
251 : :
252 : : // Create an expression for a call to FN with ARGS, taking place within
253 : : // caller CALLER.
254 : : tree call_expression (tree fn, const std::vector<tree> &args, tree static_chain,
255 : : location_t);
256 : :
257 : : // Statements.
258 : :
259 : : // Create a variable initialization statement in the specified
260 : : // function. This initializes a local variable at the point in the
261 : : // program flow where it is declared.
262 : : tree init_statement (tree, Bvariable *var, tree init);
263 : :
264 : : // Create an assignment statement within the specified function.
265 : : tree assignment_statement (tree lhs, tree rhs, location_t);
266 : :
267 : : // Create return statement for an decl for a value (can be NULL_TREE) at a
268 : : // location
269 : : tree return_statement (tree fndecl, tree val, location_t);
270 : :
271 : : // Create an if statement within a function. ELSE_BLOCK may be NULL.
272 : : tree if_statement (tree, tree condition, tree then_block, tree else_block,
273 : : location_t);
274 : :
275 : : // infinite loop expressions
276 : : tree loop_expression (tree body, location_t);
277 : :
278 : : // exit expressions
279 : : tree exit_expression (tree condition, location_t);
280 : :
281 : : // Create a single statement from two statements.
282 : : tree compound_statement (tree, tree);
283 : :
284 : : // Create a single statement from a list of statements.
285 : : tree statement_list (const std::vector<tree> &);
286 : :
287 : : // Create a statement that attempts to execute BSTAT and calls EXCEPT_STMT if
288 : : // an exception occurs. EXCEPT_STMT may be NULL. FINALLY_STMT may be NULL and
289 : : // if not NULL, it will always be executed. This is used for handling defers
290 : : // in Go functions. In C++, the resulting code is of this form:
291 : : // try { BSTAT; } catch { EXCEPT_STMT; } finally { FINALLY_STMT; }
292 : : tree exception_handler_statement (tree bstat, tree except_stmt,
293 : : tree finally_stmt, location_t);
294 : :
295 : : // Blocks.
296 : :
297 : : // Create a block. The frontend will call this function when it
298 : : // starts converting a block within a function. FUNCTION is the
299 : : // current function. ENCLOSING is the enclosing block; it will be
300 : : // NULL for the top-level block in a function. VARS is the list of
301 : : // local variables defined within this block; each entry will be
302 : : // created by the local_variable function. START_LOCATION is the
303 : : // location of the start of the block, more or less the location of
304 : : // the initial curly brace. END_LOCATION is the location of the end
305 : : // of the block, more or less the location of the final curly brace.
306 : : // The statements will be added after the block is created.
307 : : tree block (tree function, tree enclosing, const std::vector<Bvariable *> &vars,
308 : : location_t start_location, location_t end_location);
309 : :
310 : : // Add the statements to a block. The block is created first. Then
311 : : // the statements are created. Then the statements are added to the
312 : : // block. This will called exactly once per block. The vector may
313 : : // be empty if there are no statements.
314 : : void block_add_statements (tree, const std::vector<tree> &);
315 : :
316 : : // Variables.
317 : :
318 : : // Create a global variable. NAME is the package-qualified name of
319 : : // the variable. ASM_NAME is the encoded identifier for the
320 : : // variable, incorporating the package, and made safe for the
321 : : // assembler. BTYPE is the type of the variable. IS_EXTERNAL is
322 : : // true if the variable is defined in some other package. IS_HIDDEN
323 : : // is true if the variable is not exported (name begins with a lower
324 : : // case letter). IN_UNIQUE_SECTION is true if the variable should
325 : : // be put into a unique section if possible; this is intended to
326 : : // permit the linker to garbage collect the variable if it is not
327 : : // referenced. LOCATION is where the variable was defined.
328 : : Bvariable *global_variable (GGC::Ident name, GGC::Ident asm_name, tree btype,
329 : : bool is_external, bool is_hidden,
330 : : bool in_unique_section, location_t location);
331 : :
332 : : // A global variable will 1) be initialized to zero, or 2) be
333 : : // initialized to a constant value, or 3) be initialized in the init
334 : : // function. In case 2, the frontend will call
335 : : // global_variable_set_init to set the initial value. If this is
336 : : // not called, the backend should initialize a global variable to 0.
337 : : // The init function may then assign a value to it.
338 : : void global_variable_set_init (Bvariable *, tree);
339 : :
340 : : // Create a local variable. The frontend will create the local
341 : : // variables first, and then create the block which contains them.
342 : : // FUNCTION is the function in which the variable is defined. NAME
343 : : // is the name of the variable. TYPE is the type. DECL_VAR, if not
344 : : // null, gives the location at which the value of this variable may
345 : : // be found, typically used to create an inner-scope reference to an
346 : : // outer-scope variable, to extend the lifetime of the variable beyond
347 : : // the inner scope. IS_ADDRESS_TAKEN is true if the address of this
348 : : // variable is taken (this implies that the address does not escape
349 : : // the function, as otherwise the variable would be on the heap).
350 : : // LOCATION is where the variable is defined. For each local variable
351 : : // the frontend will call init_statement to set the initial value.
352 : : Bvariable *local_variable (tree function, GGC::Ident name, tree type,
353 : : Bvariable *decl_var, location_t location);
354 : :
355 : : // Create a function parameter. This is an incoming parameter, not
356 : : // a result parameter (result parameters are treated as local
357 : : // variables). The arguments are as for local_variable.
358 : : Bvariable *parameter_variable (tree function, GGC::Ident name, tree type,
359 : : location_t location);
360 : :
361 : : // Create a static chain parameter. This is the closure parameter.
362 : : Bvariable *static_chain_variable (tree function, GGC::Ident name, tree type,
363 : : location_t location);
364 : :
365 : : // Create a temporary variable. A temporary variable has no name,
366 : : // just a type. We pass in FUNCTION and BLOCK in case they are
367 : : // needed. If INIT is not NULL, the variable should be initialized
368 : : // to that value. Otherwise the initial value is irrelevant--the
369 : : // backend does not have to explicitly initialize it to zero.
370 : : // ADDRESS_IS_TAKEN is true if the programs needs to take the
371 : : // address of this temporary variable. LOCATION is the location of
372 : : // the statement or expression which requires creating the temporary
373 : : // variable, and may not be very useful. This function should
374 : : // return a variable which can be referenced later and should set
375 : : // *PSTATEMENT to a statement which initializes the variable.
376 : : Bvariable *temporary_variable (tree fndecl, tree bind_tree, tree type,
377 : : tree init, bool address_is_taken,
378 : : location_t location, tree *pstatement);
379 : :
380 : : // Labels.
381 : :
382 : : // Create a new label. NAME will be tl::nullopt if this is a label
383 : : // created by the frontend for a loop construct. The location is
384 : : // where the label is defined.
385 : : tree label (tree, tl::optional<GGC::Ident> name, location_t);
386 : :
387 : : // Create a statement which defines a label. This statement will be
388 : : // put into the codestream at the point where the label should be
389 : : // defined.
390 : : tree label_definition_statement (tree);
391 : :
392 : : // Create a goto statement to a label.
393 : : tree goto_statement (tree, location_t);
394 : :
395 : : // Create an expression for the address of a label. This is used to
396 : : // get the return address of a deferred function which may call
397 : : // recover.
398 : : tree label_address (tree, location_t);
399 : :
400 : : // Lookup a field from a type given its name.
401 : : // Build the `component` tree with `Backend::get_identifier_node`.
402 : : //
403 : : // Forked from the C frontend.
404 : : tree lookup_field (const_tree, tree);
405 : :
406 : : // Functions.
407 : :
408 : : // Bit flags to pass to the function method.
409 : :
410 : : // Set if this is a function declaration rather than a definition;
411 : : // the definition will be in another compilation unit.
412 : : static const unsigned int function_is_declaration = 1 << 0;
413 : :
414 : : // Set if the function should never be inlined because they call
415 : : // recover and must be visible for correct panic recovery.
416 : : static const unsigned int function_is_uninlinable = 1 << 1;
417 : :
418 : : // Set if the function does not return. This is set for the
419 : : // implementation of panic.
420 : : static const unsigned int function_does_not_return = 1 << 2;
421 : :
422 : : // Set if the function should be put in a unique section if
423 : : // possible. This is used for field tracking.
424 : : static const unsigned int function_in_unique_section = 1 << 3;
425 : :
426 : : // Declare or define a function of FNTYPE.
427 : : // NAME is the Go name of the function. ASM_NAME, if not tl::nullopt,
428 : : // is the name that should be used in the symbol table; this
429 : : // will be non-empty if a magic extern comment is used. FLAGS is
430 : : // bit flags described above.
431 : : tree function (tree fntype, GGC::Ident name, tl::optional<GGC::Ident> asm_name,
432 : : unsigned int flags, location_t);
433 : :
434 : : // Create a statement that runs all deferred calls for FUNCTION. This should
435 : : // be a statement that looks like this in C++:
436 : : // finish:
437 : : // try { DEFER_RETURN; } catch { CHECK_DEFER; goto finish; }
438 : : tree function_defer_statement (tree function, tree undefer, tree check_defer,
439 : : location_t);
440 : :
441 : : // Record PARAM_VARS as the variables to use for the parameters of FUNCTION.
442 : : // This will only be called for a function definition. Returns true on
443 : : // success, false on failure.
444 : : bool function_set_parameters (tree function,
445 : : const std::vector<Bvariable *> ¶m_vars);
446 : :
447 : : // Utility.
448 : :
449 : : // Write the definitions for all TYPE_DECLS, CONSTANT_DECLS,
450 : : // FUNCTION_DECLS, and VARIABLE_DECLS declared globally.
451 : : void write_global_definitions (const std::vector<tree> &type_decls,
452 : : const std::vector<tree> &constant_decls,
453 : : const std::vector<tree> &function_decls,
454 : : const std::vector<Bvariable *> &variable_decls);
455 : :
456 : : // TODO: make static
457 : :
458 : : tree fill_in_fields (tree, const std::vector<typed_identifier> &, bool);
459 : :
460 : : tree fill_in_array (tree, tree, tree);
461 : :
462 : : tree non_zero_size_type (tree);
463 : :
464 : : tree convert_tree (tree, tree, location_t);
465 : :
466 : : } // namespace Backend
467 : :
468 : : #endif // RUST_BACKEND_H
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