1 /*===-- llvm-c/lto.h - LTO Public C Interface ---------------------*- C -*-===*\
2 |*                                                                            *|
3 |* Part of the LLVM Project, under the Apache License v2.0 with LLVM          *|
4 |* Exceptions.                                                                *|
5 |* See https://llvm.org/LICENSE.txt for license information.                  *|
6 |* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception                    *|
7 |*                                                                            *|
8 |*===----------------------------------------------------------------------===*|
9 |*                                                                            *|
10 |* This header provides public interface to an abstract link time optimization*|
11 |* library.  LLVM provides an implementation of this interface for use with   *|
12 |* llvm bitcode files.                                                        *|
13 |*                                                                            *|
14 \*===----------------------------------------------------------------------===*/
15 
16 #ifndef LLVM_C_LTO_H
17 #define LLVM_C_LTO_H
18 
19 #include "llvm-c/ExternC.h"
20 
21 #ifdef __cplusplus
22 #include <cstddef>
23 #else
24 #include <stddef.h>
25 #endif
26 #include <sys/types.h>
27 
28 #ifndef __cplusplus
29 #if !defined(_MSC_VER)
30 #include <stdbool.h>
31 typedef bool lto_bool_t;
32 #else
33 /* MSVC in particular does not have anything like _Bool or bool in C, but we can
34    at least make sure the type is the same size.  The implementation side will
35    use C++ bool. */
36 typedef unsigned char lto_bool_t;
37 #endif
38 #else
39 typedef bool lto_bool_t;
40 #endif
41 
42 /**
43  * @defgroup LLVMCLTO LTO
44  * @ingroup LLVMC
45  *
46  * @{
47  */
48 
49 #define LTO_API_VERSION 26
50 
51 /**
52  * \since prior to LTO_API_VERSION=3
53  */
54 typedef enum {
55     LTO_SYMBOL_ALIGNMENT_MASK              = 0x0000001F, /* log2 of alignment */
56     LTO_SYMBOL_PERMISSIONS_MASK            = 0x000000E0,
57     LTO_SYMBOL_PERMISSIONS_CODE            = 0x000000A0,
58     LTO_SYMBOL_PERMISSIONS_DATA            = 0x000000C0,
59     LTO_SYMBOL_PERMISSIONS_RODATA          = 0x00000080,
60     LTO_SYMBOL_DEFINITION_MASK             = 0x00000700,
61     LTO_SYMBOL_DEFINITION_REGULAR          = 0x00000100,
62     LTO_SYMBOL_DEFINITION_TENTATIVE        = 0x00000200,
63     LTO_SYMBOL_DEFINITION_WEAK             = 0x00000300,
64     LTO_SYMBOL_DEFINITION_UNDEFINED        = 0x00000400,
65     LTO_SYMBOL_DEFINITION_WEAKUNDEF        = 0x00000500,
66     LTO_SYMBOL_SCOPE_MASK                  = 0x00003800,
67     LTO_SYMBOL_SCOPE_INTERNAL              = 0x00000800,
68     LTO_SYMBOL_SCOPE_HIDDEN                = 0x00001000,
69     LTO_SYMBOL_SCOPE_PROTECTED             = 0x00002000,
70     LTO_SYMBOL_SCOPE_DEFAULT               = 0x00001800,
71     LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN = 0x00002800,
72     LTO_SYMBOL_COMDAT                      = 0x00004000,
73     LTO_SYMBOL_ALIAS                       = 0x00008000
74 } lto_symbol_attributes;
75 
76 /**
77  * \since prior to LTO_API_VERSION=3
78  */
79 typedef enum {
80     LTO_DEBUG_MODEL_NONE         = 0,
81     LTO_DEBUG_MODEL_DWARF        = 1
82 } lto_debug_model;
83 
84 /**
85  * \since prior to LTO_API_VERSION=3
86  */
87 typedef enum {
88     LTO_CODEGEN_PIC_MODEL_STATIC         = 0,
89     LTO_CODEGEN_PIC_MODEL_DYNAMIC        = 1,
90     LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC = 2,
91     LTO_CODEGEN_PIC_MODEL_DEFAULT        = 3
92 } lto_codegen_model;
93 
94 /** opaque reference to a loaded object module */
95 typedef struct LLVMOpaqueLTOModule *lto_module_t;
96 
97 /** opaque reference to a code generator */
98 typedef struct LLVMOpaqueLTOCodeGenerator *lto_code_gen_t;
99 
100 /** opaque reference to a thin code generator */
101 typedef struct LLVMOpaqueThinLTOCodeGenerator *thinlto_code_gen_t;
102 
103 LLVM_C_EXTERN_C_BEGIN
104 
105 /**
106  * Returns a printable string.
107  *
108  * \since prior to LTO_API_VERSION=3
109  */
110 extern const char*
111 lto_get_version(void);
112 
113 /**
114  * Returns the last error string or NULL if last operation was successful.
115  *
116  * \since prior to LTO_API_VERSION=3
117  */
118 extern const char*
119 lto_get_error_message(void);
120 
121 /**
122  * Checks if a file is a loadable object file.
123  *
124  * \since prior to LTO_API_VERSION=3
125  */
126 extern lto_bool_t
127 lto_module_is_object_file(const char* path);
128 
129 /**
130  * Checks if a file is a loadable object compiled for requested target.
131  *
132  * \since prior to LTO_API_VERSION=3
133  */
134 extern lto_bool_t
135 lto_module_is_object_file_for_target(const char* path,
136                                      const char* target_triple_prefix);
137 
138 /**
139  * Return true if \p Buffer contains a bitcode file with ObjC code (category
140  * or class) in it.
141  *
142  * \since LTO_API_VERSION=20
143  */
144 extern lto_bool_t
145 lto_module_has_objc_category(const void *mem, size_t length);
146 
147 /**
148  * Checks if a buffer is a loadable object file.
149  *
150  * \since prior to LTO_API_VERSION=3
151  */
152 extern lto_bool_t lto_module_is_object_file_in_memory(const void *mem,
153                                                       size_t length);
154 
155 /**
156  * Checks if a buffer is a loadable object compiled for requested target.
157  *
158  * \since prior to LTO_API_VERSION=3
159  */
160 extern lto_bool_t
161 lto_module_is_object_file_in_memory_for_target(const void* mem, size_t length,
162                                               const char* target_triple_prefix);
163 
164 /**
165  * Loads an object file from disk.
166  * Returns NULL on error (check lto_get_error_message() for details).
167  *
168  * \since prior to LTO_API_VERSION=3
169  */
170 extern lto_module_t
171 lto_module_create(const char* path);
172 
173 /**
174  * Loads an object file from memory.
175  * Returns NULL on error (check lto_get_error_message() for details).
176  *
177  * \since prior to LTO_API_VERSION=3
178  */
179 extern lto_module_t
180 lto_module_create_from_memory(const void* mem, size_t length);
181 
182 /**
183  * Loads an object file from memory with an extra path argument.
184  * Returns NULL on error (check lto_get_error_message() for details).
185  *
186  * \since LTO_API_VERSION=9
187  */
188 extern lto_module_t
189 lto_module_create_from_memory_with_path(const void* mem, size_t length,
190                                         const char *path);
191 
192 /**
193  * Loads an object file in its own context.
194  *
195  * Loads an object file in its own LLVMContext.  This function call is
196  * thread-safe.  However, modules created this way should not be merged into an
197  * lto_code_gen_t using \a lto_codegen_add_module().
198  *
199  * Returns NULL on error (check lto_get_error_message() for details).
200  *
201  * \since LTO_API_VERSION=11
202  */
203 extern lto_module_t
204 lto_module_create_in_local_context(const void *mem, size_t length,
205                                    const char *path);
206 
207 /**
208  * Loads an object file in the codegen context.
209  *
210  * Loads an object file into the same context as \c cg.  The module is safe to
211  * add using \a lto_codegen_add_module().
212  *
213  * Returns NULL on error (check lto_get_error_message() for details).
214  *
215  * \since LTO_API_VERSION=11
216  */
217 extern lto_module_t
218 lto_module_create_in_codegen_context(const void *mem, size_t length,
219                                      const char *path, lto_code_gen_t cg);
220 
221 /**
222  * Loads an object file from disk. The seek point of fd is not preserved.
223  * Returns NULL on error (check lto_get_error_message() for details).
224  *
225  * \since LTO_API_VERSION=5
226  */
227 extern lto_module_t
228 lto_module_create_from_fd(int fd, const char *path, size_t file_size);
229 
230 /**
231  * Loads an object file from disk. The seek point of fd is not preserved.
232  * Returns NULL on error (check lto_get_error_message() for details).
233  *
234  * \since LTO_API_VERSION=5
235  */
236 extern lto_module_t
237 lto_module_create_from_fd_at_offset(int fd, const char *path, size_t file_size,
238                                     size_t map_size, off_t offset);
239 
240 /**
241  * Frees all memory internally allocated by the module.
242  * Upon return the lto_module_t is no longer valid.
243  *
244  * \since prior to LTO_API_VERSION=3
245  */
246 extern void
247 lto_module_dispose(lto_module_t mod);
248 
249 /**
250  * Returns triple string which the object module was compiled under.
251  *
252  * \since prior to LTO_API_VERSION=3
253  */
254 extern const char*
255 lto_module_get_target_triple(lto_module_t mod);
256 
257 /**
258  * Sets triple string with which the object will be codegened.
259  *
260  * \since LTO_API_VERSION=4
261  */
262 extern void
263 lto_module_set_target_triple(lto_module_t mod, const char *triple);
264 
265 /**
266  * Returns the number of symbols in the object module.
267  *
268  * \since prior to LTO_API_VERSION=3
269  */
270 extern unsigned int
271 lto_module_get_num_symbols(lto_module_t mod);
272 
273 /**
274  * Returns the name of the ith symbol in the object module.
275  *
276  * \since prior to LTO_API_VERSION=3
277  */
278 extern const char*
279 lto_module_get_symbol_name(lto_module_t mod, unsigned int index);
280 
281 /**
282  * Returns the attributes of the ith symbol in the object module.
283  *
284  * \since prior to LTO_API_VERSION=3
285  */
286 extern lto_symbol_attributes
287 lto_module_get_symbol_attribute(lto_module_t mod, unsigned int index);
288 
289 /**
290  * Returns the module's linker options.
291  *
292  * The linker options may consist of multiple flags. It is the linker's
293  * responsibility to split the flags using a platform-specific mechanism.
294  *
295  * \since LTO_API_VERSION=16
296  */
297 extern const char*
298 lto_module_get_linkeropts(lto_module_t mod);
299 
300 /**
301  * Diagnostic severity.
302  *
303  * \since LTO_API_VERSION=7
304  */
305 typedef enum {
306   LTO_DS_ERROR = 0,
307   LTO_DS_WARNING = 1,
308   LTO_DS_REMARK = 3, // Added in LTO_API_VERSION=10.
309   LTO_DS_NOTE = 2
310 } lto_codegen_diagnostic_severity_t;
311 
312 /**
313  * Diagnostic handler type.
314  * \p severity defines the severity.
315  * \p diag is the actual diagnostic.
316  * The diagnostic is not prefixed by any of severity keyword, e.g., 'error: '.
317  * \p ctxt is used to pass the context set with the diagnostic handler.
318  *
319  * \since LTO_API_VERSION=7
320  */
321 typedef void (*lto_diagnostic_handler_t)(
322     lto_codegen_diagnostic_severity_t severity, const char *diag, void *ctxt);
323 
324 /**
325  * Set a diagnostic handler and the related context (void *).
326  * This is more general than lto_get_error_message, as the diagnostic handler
327  * can be called at anytime within lto.
328  *
329  * \since LTO_API_VERSION=7
330  */
331 extern void lto_codegen_set_diagnostic_handler(lto_code_gen_t,
332                                                lto_diagnostic_handler_t,
333                                                void *);
334 
335 /**
336  * Instantiates a code generator.
337  * Returns NULL on error (check lto_get_error_message() for details).
338  *
339  * All modules added using \a lto_codegen_add_module() must have been created
340  * in the same context as the codegen.
341  *
342  * \since prior to LTO_API_VERSION=3
343  */
344 extern lto_code_gen_t
345 lto_codegen_create(void);
346 
347 /**
348  * Instantiate a code generator in its own context.
349  *
350  * Instantiates a code generator in its own context.  Modules added via \a
351  * lto_codegen_add_module() must have all been created in the same context,
352  * using \a lto_module_create_in_codegen_context().
353  *
354  * \since LTO_API_VERSION=11
355  */
356 extern lto_code_gen_t
357 lto_codegen_create_in_local_context(void);
358 
359 /**
360  * Frees all code generator and all memory it internally allocated.
361  * Upon return the lto_code_gen_t is no longer valid.
362  *
363  * \since prior to LTO_API_VERSION=3
364  */
365 extern void
366 lto_codegen_dispose(lto_code_gen_t);
367 
368 /**
369  * Add an object module to the set of modules for which code will be generated.
370  * Returns true on error (check lto_get_error_message() for details).
371  *
372  * \c cg and \c mod must both be in the same context.  See \a
373  * lto_codegen_create_in_local_context() and \a
374  * lto_module_create_in_codegen_context().
375  *
376  * \since prior to LTO_API_VERSION=3
377  */
378 extern lto_bool_t
379 lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod);
380 
381 /**
382  * Sets the object module for code generation. This will transfer the ownership
383  * of the module to the code generator.
384  *
385  * \c cg and \c mod must both be in the same context.
386  *
387  * \since LTO_API_VERSION=13
388  */
389 extern void
390 lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod);
391 
392 /**
393  * Sets if debug info should be generated.
394  * Returns true on error (check lto_get_error_message() for details).
395  *
396  * \since prior to LTO_API_VERSION=3
397  */
398 extern lto_bool_t
399 lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model);
400 
401 /**
402  * Sets which PIC code model to generated.
403  * Returns true on error (check lto_get_error_message() for details).
404  *
405  * \since prior to LTO_API_VERSION=3
406  */
407 extern lto_bool_t
408 lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model);
409 
410 /**
411  * Sets the cpu to generate code for.
412  *
413  * \since LTO_API_VERSION=4
414  */
415 extern void
416 lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu);
417 
418 /**
419  * Sets the location of the assembler tool to run. If not set, libLTO
420  * will use gcc to invoke the assembler.
421  *
422  * \since LTO_API_VERSION=3
423  */
424 extern void
425 lto_codegen_set_assembler_path(lto_code_gen_t cg, const char* path);
426 
427 /**
428  * Sets extra arguments that libLTO should pass to the assembler.
429  *
430  * \since LTO_API_VERSION=4
431  */
432 extern void
433 lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
434                                int nargs);
435 
436 /**
437  * Adds to a list of all global symbols that must exist in the final generated
438  * code. If a function is not listed there, it might be inlined into every usage
439  * and optimized away.
440  *
441  * \since prior to LTO_API_VERSION=3
442  */
443 extern void
444 lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg, const char* symbol);
445 
446 /**
447  * Writes a new object file at the specified path that contains the
448  * merged contents of all modules added so far.
449  * Returns true on error (check lto_get_error_message() for details).
450  *
451  * \since LTO_API_VERSION=5
452  */
453 extern lto_bool_t
454 lto_codegen_write_merged_modules(lto_code_gen_t cg, const char* path);
455 
456 /**
457  * Generates code for all added modules into one native object file.
458  * This calls lto_codegen_optimize then lto_codegen_compile_optimized.
459  *
460  * On success returns a pointer to a generated mach-o/ELF buffer and
461  * length set to the buffer size.  The buffer is owned by the
462  * lto_code_gen_t and will be freed when lto_codegen_dispose()
463  * is called, or lto_codegen_compile() is called again.
464  * On failure, returns NULL (check lto_get_error_message() for details).
465  *
466  * \since prior to LTO_API_VERSION=3
467  */
468 extern const void*
469 lto_codegen_compile(lto_code_gen_t cg, size_t* length);
470 
471 /**
472  * Generates code for all added modules into one native object file.
473  * This calls lto_codegen_optimize then lto_codegen_compile_optimized (instead
474  * of returning a generated mach-o/ELF buffer, it writes to a file).
475  *
476  * The name of the file is written to name. Returns true on error.
477  *
478  * \since LTO_API_VERSION=5
479  */
480 extern lto_bool_t
481 lto_codegen_compile_to_file(lto_code_gen_t cg, const char** name);
482 
483 /**
484  * Runs optimization for the merged module. Returns true on error.
485  *
486  * \since LTO_API_VERSION=12
487  */
488 extern lto_bool_t
489 lto_codegen_optimize(lto_code_gen_t cg);
490 
491 /**
492  * Generates code for the optimized merged module into one native object file.
493  * It will not run any IR optimizations on the merged module.
494  *
495  * On success returns a pointer to a generated mach-o/ELF buffer and length set
496  * to the buffer size.  The buffer is owned by the lto_code_gen_t and will be
497  * freed when lto_codegen_dispose() is called, or
498  * lto_codegen_compile_optimized() is called again. On failure, returns NULL
499  * (check lto_get_error_message() for details).
500  *
501  * \since LTO_API_VERSION=12
502  */
503 extern const void*
504 lto_codegen_compile_optimized(lto_code_gen_t cg, size_t* length);
505 
506 /**
507  * Returns the runtime API version.
508  *
509  * \since LTO_API_VERSION=12
510  */
511 extern unsigned int
512 lto_api_version(void);
513 
514 /**
515  * Sets options to help debug codegen bugs.
516  *
517  * This function takes one or more options separated by spaces.
518  * Warning: passing file paths through this function may confuse the argument
519  * parser if the paths contain spaces.
520  *
521  * \since prior to LTO_API_VERSION=3
522  */
523 extern void
524 lto_codegen_debug_options(lto_code_gen_t cg, const char *);
525 
526 /**
527  * Same as the previous function, but takes every option separately through an
528  * array.
529  *
530  * \since prior to LTO_API_VERSION=26
531  */
532 extern void lto_codegen_debug_options_array(lto_code_gen_t cg,
533                                             const char *const *, int number);
534 
535 /**
536  * Initializes LLVM disassemblers.
537  * FIXME: This doesn't really belong here.
538  *
539  * \since LTO_API_VERSION=5
540  */
541 extern void
542 lto_initialize_disassembler(void);
543 
544 /**
545  * Sets if we should run internalize pass during optimization and code
546  * generation.
547  *
548  * \since LTO_API_VERSION=14
549  */
550 extern void
551 lto_codegen_set_should_internalize(lto_code_gen_t cg,
552                                    lto_bool_t ShouldInternalize);
553 
554 /**
555  * Set whether to embed uselists in bitcode.
556  *
557  * Sets whether \a lto_codegen_write_merged_modules() should embed uselists in
558  * output bitcode.  This should be turned on for all -save-temps output.
559  *
560  * \since LTO_API_VERSION=15
561  */
562 extern void
563 lto_codegen_set_should_embed_uselists(lto_code_gen_t cg,
564                                       lto_bool_t ShouldEmbedUselists);
565 
566 /** Opaque reference to an LTO input file */
567 typedef struct LLVMOpaqueLTOInput *lto_input_t;
568 
569 /**
570   * Creates an LTO input file from a buffer. The path
571   * argument is used for diagnotics as this function
572   * otherwise does not know which file the given buffer
573   * is associated with.
574   *
575   * \since LTO_API_VERSION=24
576   */
577 extern lto_input_t lto_input_create(const void *buffer,
578                                     size_t buffer_size,
579                                     const char *path);
580 
581 /**
582   * Frees all memory internally allocated by the LTO input file.
583   * Upon return the lto_module_t is no longer valid.
584   *
585   * \since LTO_API_VERSION=24
586   */
587 extern void lto_input_dispose(lto_input_t input);
588 
589 /**
590   * Returns the number of dependent library specifiers
591   * for the given LTO input file.
592   *
593   * \since LTO_API_VERSION=24
594   */
595 extern unsigned lto_input_get_num_dependent_libraries(lto_input_t input);
596 
597 /**
598   * Returns the ith dependent library specifier
599   * for the given LTO input file. The returned
600   * string is not null-terminated.
601   *
602   * \since LTO_API_VERSION=24
603   */
604 extern const char * lto_input_get_dependent_library(lto_input_t input,
605                                                     size_t index,
606                                                     size_t *size);
607 
608 /**
609  * Returns the list of libcall symbols that can be generated by LTO
610  * that might not be visible from the symbol table of bitcode files.
611  *
612  * \since prior to LTO_API_VERSION=25
613  */
614 extern const char *const *lto_runtime_lib_symbols_list(size_t *size);
615 
616 /**
617  * @} // endgoup LLVMCLTO
618  * @defgroup LLVMCTLTO ThinLTO
619  * @ingroup LLVMC
620  *
621  * @{
622  */
623 
624 /**
625  * Type to wrap a single object returned by ThinLTO.
626  *
627  * \since LTO_API_VERSION=18
628  */
629 typedef struct {
630   const char *Buffer;
631   size_t Size;
632 } LTOObjectBuffer;
633 
634 /**
635  * Instantiates a ThinLTO code generator.
636  * Returns NULL on error (check lto_get_error_message() for details).
637  *
638  *
639  * The ThinLTOCodeGenerator is not intended to be reuse for multiple
640  * compilation: the model is that the client adds modules to the generator and
641  * ask to perform the ThinLTO optimizations / codegen, and finally destroys the
642  * codegenerator.
643  *
644  * \since LTO_API_VERSION=18
645  */
646 extern thinlto_code_gen_t thinlto_create_codegen(void);
647 
648 /**
649  * Frees the generator and all memory it internally allocated.
650  * Upon return the thinlto_code_gen_t is no longer valid.
651  *
652  * \since LTO_API_VERSION=18
653  */
654 extern void thinlto_codegen_dispose(thinlto_code_gen_t cg);
655 
656 /**
657  * Add a module to a ThinLTO code generator. Identifier has to be unique among
658  * all the modules in a code generator. The data buffer stays owned by the
659  * client, and is expected to be available for the entire lifetime of the
660  * thinlto_code_gen_t it is added to.
661  *
662  * On failure, returns NULL (check lto_get_error_message() for details).
663  *
664  *
665  * \since LTO_API_VERSION=18
666  */
667 extern void thinlto_codegen_add_module(thinlto_code_gen_t cg,
668                                        const char *identifier, const char *data,
669                                        int length);
670 
671 /**
672  * Optimize and codegen all the modules added to the codegenerator using
673  * ThinLTO. Resulting objects are accessible using thinlto_module_get_object().
674  *
675  * \since LTO_API_VERSION=18
676  */
677 extern void thinlto_codegen_process(thinlto_code_gen_t cg);
678 
679 /**
680  * Returns the number of object files produced by the ThinLTO CodeGenerator.
681  *
682  * It usually matches the number of input files, but this is not a guarantee of
683  * the API and may change in future implementation, so the client should not
684  * assume it.
685  *
686  * \since LTO_API_VERSION=18
687  */
688 extern unsigned int thinlto_module_get_num_objects(thinlto_code_gen_t cg);
689 
690 /**
691  * Returns a reference to the ith object file produced by the ThinLTO
692  * CodeGenerator.
693  *
694  * Client should use \p thinlto_module_get_num_objects() to get the number of
695  * available objects.
696  *
697  * \since LTO_API_VERSION=18
698  */
699 extern LTOObjectBuffer thinlto_module_get_object(thinlto_code_gen_t cg,
700                                                  unsigned int index);
701 
702 /**
703  * Returns the number of object files produced by the ThinLTO CodeGenerator.
704  *
705  * It usually matches the number of input files, but this is not a guarantee of
706  * the API and may change in future implementation, so the client should not
707  * assume it.
708  *
709  * \since LTO_API_VERSION=21
710  */
711 unsigned int thinlto_module_get_num_object_files(thinlto_code_gen_t cg);
712 
713 /**
714  * Returns the path to the ith object file produced by the ThinLTO
715  * CodeGenerator.
716  *
717  * Client should use \p thinlto_module_get_num_object_files() to get the number
718  * of available objects.
719  *
720  * \since LTO_API_VERSION=21
721  */
722 const char *thinlto_module_get_object_file(thinlto_code_gen_t cg,
723                                            unsigned int index);
724 
725 /**
726  * Sets which PIC code model to generate.
727  * Returns true on error (check lto_get_error_message() for details).
728  *
729  * \since LTO_API_VERSION=18
730  */
731 extern lto_bool_t thinlto_codegen_set_pic_model(thinlto_code_gen_t cg,
732                                                 lto_codegen_model);
733 
734 /**
735  * Sets the path to a directory to use as a storage for temporary bitcode files.
736  * The intention is to make the bitcode files available for debugging at various
737  * stage of the pipeline.
738  *
739  * \since LTO_API_VERSION=18
740  */
741 extern void thinlto_codegen_set_savetemps_dir(thinlto_code_gen_t cg,
742                                               const char *save_temps_dir);
743 
744 /**
745  * Set the path to a directory where to save generated object files. This
746  * path can be used by a linker to request on-disk files instead of in-memory
747  * buffers. When set, results are available through
748  * thinlto_module_get_object_file() instead of thinlto_module_get_object().
749  *
750  * \since LTO_API_VERSION=21
751  */
752 void thinlto_set_generated_objects_dir(thinlto_code_gen_t cg,
753                                        const char *save_temps_dir);
754 
755 /**
756  * Sets the cpu to generate code for.
757  *
758  * \since LTO_API_VERSION=18
759  */
760 extern void thinlto_codegen_set_cpu(thinlto_code_gen_t cg, const char *cpu);
761 
762 /**
763  * Disable CodeGen, only run the stages till codegen and stop. The output will
764  * be bitcode.
765  *
766  * \since LTO_API_VERSION=19
767  */
768 extern void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
769                                             lto_bool_t disable);
770 
771 /**
772  * Perform CodeGen only: disable all other stages.
773  *
774  * \since LTO_API_VERSION=19
775  */
776 extern void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
777                                              lto_bool_t codegen_only);
778 
779 /**
780  * Parse -mllvm style debug options.
781  *
782  * \since LTO_API_VERSION=18
783  */
784 extern void thinlto_debug_options(const char *const *options, int number);
785 
786 /**
787  * Test if a module has support for ThinLTO linking.
788  *
789  * \since LTO_API_VERSION=18
790  */
791 extern lto_bool_t lto_module_is_thinlto(lto_module_t mod);
792 
793 /**
794  * Adds a symbol to the list of global symbols that must exist in the final
795  * generated code. If a function is not listed there, it might be inlined into
796  * every usage and optimized away. For every single module, the functions
797  * referenced from code outside of the ThinLTO modules need to be added here.
798  *
799  * \since LTO_API_VERSION=18
800  */
801 extern void thinlto_codegen_add_must_preserve_symbol(thinlto_code_gen_t cg,
802                                                      const char *name,
803                                                      int length);
804 
805 /**
806  * Adds a symbol to the list of global symbols that are cross-referenced between
807  * ThinLTO files. If the ThinLTO CodeGenerator can ensure that every
808  * references from a ThinLTO module to this symbol is optimized away, then
809  * the symbol can be discarded.
810  *
811  * \since LTO_API_VERSION=18
812  */
813 extern void thinlto_codegen_add_cross_referenced_symbol(thinlto_code_gen_t cg,
814                                                         const char *name,
815                                                         int length);
816 
817 /**
818  * @} // endgoup LLVMCTLTO
819  * @defgroup LLVMCTLTO_CACHING ThinLTO Cache Control
820  * @ingroup LLVMCTLTO
821  *
822  * These entry points control the ThinLTO cache. The cache is intended to
823  * support incremental builds, and thus needs to be persistent across builds.
824  * The client enables the cache by supplying a path to an existing directory.
825  * The code generator will use this to store objects files that may be reused
826  * during a subsequent build.
827  * To avoid filling the disk space, a few knobs are provided:
828  *  - The pruning interval limits the frequency at which the garbage collector
829  *    will try to scan the cache directory to prune expired entries.
830  *    Setting to a negative number disables the pruning.
831  *  - The pruning expiration time indicates to the garbage collector how old an
832  *    entry needs to be to be removed.
833  *  - Finally, the garbage collector can be instructed to prune the cache until
834  *    the occupied space goes below a threshold.
835  * @{
836  */
837 
838 /**
839  * Sets the path to a directory to use as a cache storage for incremental build.
840  * Setting this activates caching.
841  *
842  * \since LTO_API_VERSION=18
843  */
844 extern void thinlto_codegen_set_cache_dir(thinlto_code_gen_t cg,
845                                           const char *cache_dir);
846 
847 /**
848  * Sets the cache pruning interval (in seconds). A negative value disables the
849  * pruning. An unspecified default value will be applied, and a value of 0 will
850  * force prunning to occur.
851  *
852  * \since LTO_API_VERSION=18
853  */
854 extern void thinlto_codegen_set_cache_pruning_interval(thinlto_code_gen_t cg,
855                                                        int interval);
856 
857 /**
858  * Sets the maximum cache size that can be persistent across build, in terms of
859  * percentage of the available space on the disk. Set to 100 to indicate
860  * no limit, 50 to indicate that the cache size will not be left over half the
861  * available space. A value over 100 will be reduced to 100, a value of 0 will
862  * be ignored. An unspecified default value will be applied.
863  *
864  * The formula looks like:
865  *  AvailableSpace = FreeSpace + ExistingCacheSize
866  *  NewCacheSize = AvailableSpace * P/100
867  *
868  * \since LTO_API_VERSION=18
869  */
870 extern void thinlto_codegen_set_final_cache_size_relative_to_available_space(
871     thinlto_code_gen_t cg, unsigned percentage);
872 
873 /**
874  * Sets the expiration (in seconds) for an entry in the cache. An unspecified
875  * default value will be applied. A value of 0 will be ignored.
876  *
877  * \since LTO_API_VERSION=18
878  */
879 extern void thinlto_codegen_set_cache_entry_expiration(thinlto_code_gen_t cg,
880                                                        unsigned expiration);
881 
882 /**
883  * Sets the maximum size of the cache directory (in bytes). A value over the
884  * amount of available space on the disk will be reduced to the amount of
885  * available space. An unspecified default value will be applied. A value of 0
886  * will be ignored.
887  *
888  * \since LTO_API_VERSION=22
889  */
890 extern void thinlto_codegen_set_cache_size_bytes(thinlto_code_gen_t cg,
891                                                  unsigned max_size_bytes);
892 
893 /**
894  * Same as thinlto_codegen_set_cache_size_bytes, except the maximum size is in
895  * megabytes (2^20 bytes).
896  *
897  * \since LTO_API_VERSION=23
898  */
899 extern void
900 thinlto_codegen_set_cache_size_megabytes(thinlto_code_gen_t cg,
901                                          unsigned max_size_megabytes);
902 
903 /**
904  * Sets the maximum number of files in the cache directory. An unspecified
905  * default value will be applied. A value of 0 will be ignored.
906  *
907  * \since LTO_API_VERSION=22
908  */
909 extern void thinlto_codegen_set_cache_size_files(thinlto_code_gen_t cg,
910                                                  unsigned max_size_files);
911 
912 /**
913  * @} // endgroup LLVMCTLTO_CACHING
914  */
915 
916 LLVM_C_EXTERN_C_END
917 
918 #endif /* LLVM_C_LTO_H */
919