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 28
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  * If targeting mach-o on darwin, this function gets the CPU type and subtype
302  * that will end up being encoded in the mach-o header. These are the values
303  * that can be found in mach/machine.h.
304  *
305  * \p out_cputype and \p out_cpusubtype must be non-NULL.
306  *
307  * Returns true on error (check lto_get_error_message() for details).
308  *
309  * \since LTO_API_VERSION=27
310  */
311 extern lto_bool_t lto_module_get_macho_cputype(lto_module_t mod,
312                                                unsigned int *out_cputype,
313                                                unsigned int *out_cpusubtype);
314 
315 /**
316  * Diagnostic severity.
317  *
318  * \since LTO_API_VERSION=7
319  */
320 typedef enum {
321   LTO_DS_ERROR = 0,
322   LTO_DS_WARNING = 1,
323   LTO_DS_REMARK = 3, // Added in LTO_API_VERSION=10.
324   LTO_DS_NOTE = 2
325 } lto_codegen_diagnostic_severity_t;
326 
327 /**
328  * Diagnostic handler type.
329  * \p severity defines the severity.
330  * \p diag is the actual diagnostic.
331  * The diagnostic is not prefixed by any of severity keyword, e.g., 'error: '.
332  * \p ctxt is used to pass the context set with the diagnostic handler.
333  *
334  * \since LTO_API_VERSION=7
335  */
336 typedef void (*lto_diagnostic_handler_t)(
337     lto_codegen_diagnostic_severity_t severity, const char *diag, void *ctxt);
338 
339 /**
340  * Set a diagnostic handler and the related context (void *).
341  * This is more general than lto_get_error_message, as the diagnostic handler
342  * can be called at anytime within lto.
343  *
344  * \since LTO_API_VERSION=7
345  */
346 extern void lto_codegen_set_diagnostic_handler(lto_code_gen_t,
347                                                lto_diagnostic_handler_t,
348                                                void *);
349 
350 /**
351  * Instantiates a code generator.
352  * Returns NULL on error (check lto_get_error_message() for details).
353  *
354  * All modules added using \a lto_codegen_add_module() must have been created
355  * in the same context as the codegen.
356  *
357  * \since prior to LTO_API_VERSION=3
358  */
359 extern lto_code_gen_t
360 lto_codegen_create(void);
361 
362 /**
363  * Instantiate a code generator in its own context.
364  *
365  * Instantiates a code generator in its own context.  Modules added via \a
366  * lto_codegen_add_module() must have all been created in the same context,
367  * using \a lto_module_create_in_codegen_context().
368  *
369  * \since LTO_API_VERSION=11
370  */
371 extern lto_code_gen_t
372 lto_codegen_create_in_local_context(void);
373 
374 /**
375  * Frees all code generator and all memory it internally allocated.
376  * Upon return the lto_code_gen_t is no longer valid.
377  *
378  * \since prior to LTO_API_VERSION=3
379  */
380 extern void
381 lto_codegen_dispose(lto_code_gen_t);
382 
383 /**
384  * Add an object module to the set of modules for which code will be generated.
385  * Returns true on error (check lto_get_error_message() for details).
386  *
387  * \c cg and \c mod must both be in the same context.  See \a
388  * lto_codegen_create_in_local_context() and \a
389  * lto_module_create_in_codegen_context().
390  *
391  * \since prior to LTO_API_VERSION=3
392  */
393 extern lto_bool_t
394 lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod);
395 
396 /**
397  * Sets the object module for code generation. This will transfer the ownership
398  * of the module to the code generator.
399  *
400  * \c cg and \c mod must both be in the same context.
401  *
402  * \since LTO_API_VERSION=13
403  */
404 extern void
405 lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod);
406 
407 /**
408  * Sets if debug info should be generated.
409  * Returns true on error (check lto_get_error_message() for details).
410  *
411  * \since prior to LTO_API_VERSION=3
412  */
413 extern lto_bool_t
414 lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model);
415 
416 /**
417  * Sets which PIC code model to generated.
418  * Returns true on error (check lto_get_error_message() for details).
419  *
420  * \since prior to LTO_API_VERSION=3
421  */
422 extern lto_bool_t
423 lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model);
424 
425 /**
426  * Sets the cpu to generate code for.
427  *
428  * \since LTO_API_VERSION=4
429  */
430 extern void
431 lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu);
432 
433 /**
434  * Sets the location of the assembler tool to run. If not set, libLTO
435  * will use gcc to invoke the assembler.
436  *
437  * \since LTO_API_VERSION=3
438  */
439 extern void
440 lto_codegen_set_assembler_path(lto_code_gen_t cg, const char* path);
441 
442 /**
443  * Sets extra arguments that libLTO should pass to the assembler.
444  *
445  * \since LTO_API_VERSION=4
446  */
447 extern void
448 lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
449                                int nargs);
450 
451 /**
452  * Adds to a list of all global symbols that must exist in the final generated
453  * code. If a function is not listed there, it might be inlined into every usage
454  * and optimized away.
455  *
456  * \since prior to LTO_API_VERSION=3
457  */
458 extern void
459 lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg, const char* symbol);
460 
461 /**
462  * Writes a new object file at the specified path that contains the
463  * merged contents of all modules added so far.
464  * Returns true on error (check lto_get_error_message() for details).
465  *
466  * \since LTO_API_VERSION=5
467  */
468 extern lto_bool_t
469 lto_codegen_write_merged_modules(lto_code_gen_t cg, const char* path);
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.
474  *
475  * On success returns a pointer to a generated mach-o/ELF buffer and
476  * length set to the buffer size.  The buffer is owned by the
477  * lto_code_gen_t and will be freed when lto_codegen_dispose()
478  * is called, or lto_codegen_compile() is called again.
479  * On failure, returns NULL (check lto_get_error_message() for details).
480  *
481  * \since prior to LTO_API_VERSION=3
482  */
483 extern const void*
484 lto_codegen_compile(lto_code_gen_t cg, size_t* length);
485 
486 /**
487  * Generates code for all added modules into one native object file.
488  * This calls lto_codegen_optimize then lto_codegen_compile_optimized (instead
489  * of returning a generated mach-o/ELF buffer, it writes to a file).
490  *
491  * The name of the file is written to name. Returns true on error.
492  *
493  * \since LTO_API_VERSION=5
494  */
495 extern lto_bool_t
496 lto_codegen_compile_to_file(lto_code_gen_t cg, const char** name);
497 
498 /**
499  * Runs optimization for the merged module. Returns true on error.
500  *
501  * \since LTO_API_VERSION=12
502  */
503 extern lto_bool_t
504 lto_codegen_optimize(lto_code_gen_t cg);
505 
506 /**
507  * Generates code for the optimized merged module into one native object file.
508  * It will not run any IR optimizations on the merged module.
509  *
510  * On success returns a pointer to a generated mach-o/ELF buffer and length set
511  * to the buffer size.  The buffer is owned by the lto_code_gen_t and will be
512  * freed when lto_codegen_dispose() is called, or
513  * lto_codegen_compile_optimized() is called again. On failure, returns NULL
514  * (check lto_get_error_message() for details).
515  *
516  * \since LTO_API_VERSION=12
517  */
518 extern const void*
519 lto_codegen_compile_optimized(lto_code_gen_t cg, size_t* length);
520 
521 /**
522  * Returns the runtime API version.
523  *
524  * \since LTO_API_VERSION=12
525  */
526 extern unsigned int
527 lto_api_version(void);
528 
529 /**
530  * Parses options immediately, making them available as early as possible. For
531  * example during executing codegen::InitTargetOptionsFromCodeGenFlags. Since
532  * parsing shud only happen once, only one of lto_codegen_debug_options or
533  * lto_set_debug_options should be called.
534  *
535  * This function takes one or more options separated by spaces.
536  * Warning: passing file paths through this function may confuse the argument
537  * parser if the paths contain spaces.
538  *
539  * \since LTO_API_VERSION=28
540  */
541 extern void lto_set_debug_options(const char *const *options, int number);
542 
543 /**
544  * Sets options to help debug codegen bugs. Since parsing shud only happen once,
545  * only one of lto_codegen_debug_options or lto_set_debug_options
546  * should be called.
547  *
548  * This function takes one or more options separated by spaces.
549  * Warning: passing file paths through this function may confuse the argument
550  * parser if the paths contain spaces.
551  *
552  * \since prior to LTO_API_VERSION=3
553  */
554 extern void
555 lto_codegen_debug_options(lto_code_gen_t cg, const char *);
556 
557 /**
558  * Same as the previous function, but takes every option separately through an
559  * array.
560  *
561  * \since prior to LTO_API_VERSION=26
562  */
563 extern void lto_codegen_debug_options_array(lto_code_gen_t cg,
564                                             const char *const *, int number);
565 
566 /**
567  * Initializes LLVM disassemblers.
568  * FIXME: This doesn't really belong here.
569  *
570  * \since LTO_API_VERSION=5
571  */
572 extern void
573 lto_initialize_disassembler(void);
574 
575 /**
576  * Sets if we should run internalize pass during optimization and code
577  * generation.
578  *
579  * \since LTO_API_VERSION=14
580  */
581 extern void
582 lto_codegen_set_should_internalize(lto_code_gen_t cg,
583                                    lto_bool_t ShouldInternalize);
584 
585 /**
586  * Set whether to embed uselists in bitcode.
587  *
588  * Sets whether \a lto_codegen_write_merged_modules() should embed uselists in
589  * output bitcode.  This should be turned on for all -save-temps output.
590  *
591  * \since LTO_API_VERSION=15
592  */
593 extern void
594 lto_codegen_set_should_embed_uselists(lto_code_gen_t cg,
595                                       lto_bool_t ShouldEmbedUselists);
596 
597 /** Opaque reference to an LTO input file */
598 typedef struct LLVMOpaqueLTOInput *lto_input_t;
599 
600 /**
601   * Creates an LTO input file from a buffer. The path
602   * argument is used for diagnotics as this function
603   * otherwise does not know which file the given buffer
604   * is associated with.
605   *
606   * \since LTO_API_VERSION=24
607   */
608 extern lto_input_t lto_input_create(const void *buffer,
609                                     size_t buffer_size,
610                                     const char *path);
611 
612 /**
613   * Frees all memory internally allocated by the LTO input file.
614   * Upon return the lto_module_t is no longer valid.
615   *
616   * \since LTO_API_VERSION=24
617   */
618 extern void lto_input_dispose(lto_input_t input);
619 
620 /**
621   * Returns the number of dependent library specifiers
622   * for the given LTO input file.
623   *
624   * \since LTO_API_VERSION=24
625   */
626 extern unsigned lto_input_get_num_dependent_libraries(lto_input_t input);
627 
628 /**
629   * Returns the ith dependent library specifier
630   * for the given LTO input file. The returned
631   * string is not null-terminated.
632   *
633   * \since LTO_API_VERSION=24
634   */
635 extern const char * lto_input_get_dependent_library(lto_input_t input,
636                                                     size_t index,
637                                                     size_t *size);
638 
639 /**
640  * Returns the list of libcall symbols that can be generated by LTO
641  * that might not be visible from the symbol table of bitcode files.
642  *
643  * \since prior to LTO_API_VERSION=25
644  */
645 extern const char *const *lto_runtime_lib_symbols_list(size_t *size);
646 
647 /**
648  * @} // endgoup LLVMCLTO
649  * @defgroup LLVMCTLTO ThinLTO
650  * @ingroup LLVMC
651  *
652  * @{
653  */
654 
655 /**
656  * Type to wrap a single object returned by ThinLTO.
657  *
658  * \since LTO_API_VERSION=18
659  */
660 typedef struct {
661   const char *Buffer;
662   size_t Size;
663 } LTOObjectBuffer;
664 
665 /**
666  * Instantiates a ThinLTO code generator.
667  * Returns NULL on error (check lto_get_error_message() for details).
668  *
669  *
670  * The ThinLTOCodeGenerator is not intended to be reuse for multiple
671  * compilation: the model is that the client adds modules to the generator and
672  * ask to perform the ThinLTO optimizations / codegen, and finally destroys the
673  * codegenerator.
674  *
675  * \since LTO_API_VERSION=18
676  */
677 extern thinlto_code_gen_t thinlto_create_codegen(void);
678 
679 /**
680  * Frees the generator and all memory it internally allocated.
681  * Upon return the thinlto_code_gen_t is no longer valid.
682  *
683  * \since LTO_API_VERSION=18
684  */
685 extern void thinlto_codegen_dispose(thinlto_code_gen_t cg);
686 
687 /**
688  * Add a module to a ThinLTO code generator. Identifier has to be unique among
689  * all the modules in a code generator. The data buffer stays owned by the
690  * client, and is expected to be available for the entire lifetime of the
691  * thinlto_code_gen_t it is added to.
692  *
693  * On failure, returns NULL (check lto_get_error_message() for details).
694  *
695  *
696  * \since LTO_API_VERSION=18
697  */
698 extern void thinlto_codegen_add_module(thinlto_code_gen_t cg,
699                                        const char *identifier, const char *data,
700                                        int length);
701 
702 /**
703  * Optimize and codegen all the modules added to the codegenerator using
704  * ThinLTO. Resulting objects are accessible using thinlto_module_get_object().
705  *
706  * \since LTO_API_VERSION=18
707  */
708 extern void thinlto_codegen_process(thinlto_code_gen_t cg);
709 
710 /**
711  * Returns the number of object files produced by the ThinLTO CodeGenerator.
712  *
713  * It usually matches the number of input files, but this is not a guarantee of
714  * the API and may change in future implementation, so the client should not
715  * assume it.
716  *
717  * \since LTO_API_VERSION=18
718  */
719 extern unsigned int thinlto_module_get_num_objects(thinlto_code_gen_t cg);
720 
721 /**
722  * Returns a reference to the ith object file produced by the ThinLTO
723  * CodeGenerator.
724  *
725  * Client should use \p thinlto_module_get_num_objects() to get the number of
726  * available objects.
727  *
728  * \since LTO_API_VERSION=18
729  */
730 extern LTOObjectBuffer thinlto_module_get_object(thinlto_code_gen_t cg,
731                                                  unsigned int index);
732 
733 /**
734  * Returns the number of object files produced by the ThinLTO CodeGenerator.
735  *
736  * It usually matches the number of input files, but this is not a guarantee of
737  * the API and may change in future implementation, so the client should not
738  * assume it.
739  *
740  * \since LTO_API_VERSION=21
741  */
742 unsigned int thinlto_module_get_num_object_files(thinlto_code_gen_t cg);
743 
744 /**
745  * Returns the path to the ith object file produced by the ThinLTO
746  * CodeGenerator.
747  *
748  * Client should use \p thinlto_module_get_num_object_files() to get the number
749  * of available objects.
750  *
751  * \since LTO_API_VERSION=21
752  */
753 const char *thinlto_module_get_object_file(thinlto_code_gen_t cg,
754                                            unsigned int index);
755 
756 /**
757  * Sets which PIC code model to generate.
758  * Returns true on error (check lto_get_error_message() for details).
759  *
760  * \since LTO_API_VERSION=18
761  */
762 extern lto_bool_t thinlto_codegen_set_pic_model(thinlto_code_gen_t cg,
763                                                 lto_codegen_model);
764 
765 /**
766  * Sets the path to a directory to use as a storage for temporary bitcode files.
767  * The intention is to make the bitcode files available for debugging at various
768  * stage of the pipeline.
769  *
770  * \since LTO_API_VERSION=18
771  */
772 extern void thinlto_codegen_set_savetemps_dir(thinlto_code_gen_t cg,
773                                               const char *save_temps_dir);
774 
775 /**
776  * Set the path to a directory where to save generated object files. This
777  * path can be used by a linker to request on-disk files instead of in-memory
778  * buffers. When set, results are available through
779  * thinlto_module_get_object_file() instead of thinlto_module_get_object().
780  *
781  * \since LTO_API_VERSION=21
782  */
783 void thinlto_set_generated_objects_dir(thinlto_code_gen_t cg,
784                                        const char *save_temps_dir);
785 
786 /**
787  * Sets the cpu to generate code for.
788  *
789  * \since LTO_API_VERSION=18
790  */
791 extern void thinlto_codegen_set_cpu(thinlto_code_gen_t cg, const char *cpu);
792 
793 /**
794  * Disable CodeGen, only run the stages till codegen and stop. The output will
795  * be bitcode.
796  *
797  * \since LTO_API_VERSION=19
798  */
799 extern void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
800                                             lto_bool_t disable);
801 
802 /**
803  * Perform CodeGen only: disable all other stages.
804  *
805  * \since LTO_API_VERSION=19
806  */
807 extern void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
808                                              lto_bool_t codegen_only);
809 
810 /**
811  * Parse -mllvm style debug options.
812  *
813  * \since LTO_API_VERSION=18
814  */
815 extern void thinlto_debug_options(const char *const *options, int number);
816 
817 /**
818  * Test if a module has support for ThinLTO linking.
819  *
820  * \since LTO_API_VERSION=18
821  */
822 extern lto_bool_t lto_module_is_thinlto(lto_module_t mod);
823 
824 /**
825  * Adds a symbol to the list of global symbols that must exist in the final
826  * generated code. If a function is not listed there, it might be inlined into
827  * every usage and optimized away. For every single module, the functions
828  * referenced from code outside of the ThinLTO modules need to be added here.
829  *
830  * \since LTO_API_VERSION=18
831  */
832 extern void thinlto_codegen_add_must_preserve_symbol(thinlto_code_gen_t cg,
833                                                      const char *name,
834                                                      int length);
835 
836 /**
837  * Adds a symbol to the list of global symbols that are cross-referenced between
838  * ThinLTO files. If the ThinLTO CodeGenerator can ensure that every
839  * references from a ThinLTO module to this symbol is optimized away, then
840  * the symbol can be discarded.
841  *
842  * \since LTO_API_VERSION=18
843  */
844 extern void thinlto_codegen_add_cross_referenced_symbol(thinlto_code_gen_t cg,
845                                                         const char *name,
846                                                         int length);
847 
848 /**
849  * @} // endgoup LLVMCTLTO
850  * @defgroup LLVMCTLTO_CACHING ThinLTO Cache Control
851  * @ingroup LLVMCTLTO
852  *
853  * These entry points control the ThinLTO cache. The cache is intended to
854  * support incremental builds, and thus needs to be persistent across builds.
855  * The client enables the cache by supplying a path to an existing directory.
856  * The code generator will use this to store objects files that may be reused
857  * during a subsequent build.
858  * To avoid filling the disk space, a few knobs are provided:
859  *  - The pruning interval limits the frequency at which the garbage collector
860  *    will try to scan the cache directory to prune expired entries.
861  *    Setting to a negative number disables the pruning.
862  *  - The pruning expiration time indicates to the garbage collector how old an
863  *    entry needs to be to be removed.
864  *  - Finally, the garbage collector can be instructed to prune the cache until
865  *    the occupied space goes below a threshold.
866  * @{
867  */
868 
869 /**
870  * Sets the path to a directory to use as a cache storage for incremental build.
871  * Setting this activates caching.
872  *
873  * \since LTO_API_VERSION=18
874  */
875 extern void thinlto_codegen_set_cache_dir(thinlto_code_gen_t cg,
876                                           const char *cache_dir);
877 
878 /**
879  * Sets the cache pruning interval (in seconds). A negative value disables the
880  * pruning. An unspecified default value will be applied, and a value of 0 will
881  * force prunning to occur.
882  *
883  * \since LTO_API_VERSION=18
884  */
885 extern void thinlto_codegen_set_cache_pruning_interval(thinlto_code_gen_t cg,
886                                                        int interval);
887 
888 /**
889  * Sets the maximum cache size that can be persistent across build, in terms of
890  * percentage of the available space on the disk. Set to 100 to indicate
891  * no limit, 50 to indicate that the cache size will not be left over half the
892  * available space. A value over 100 will be reduced to 100, a value of 0 will
893  * be ignored. An unspecified default value will be applied.
894  *
895  * The formula looks like:
896  *  AvailableSpace = FreeSpace + ExistingCacheSize
897  *  NewCacheSize = AvailableSpace * P/100
898  *
899  * \since LTO_API_VERSION=18
900  */
901 extern void thinlto_codegen_set_final_cache_size_relative_to_available_space(
902     thinlto_code_gen_t cg, unsigned percentage);
903 
904 /**
905  * Sets the expiration (in seconds) for an entry in the cache. An unspecified
906  * default value will be applied. A value of 0 will be ignored.
907  *
908  * \since LTO_API_VERSION=18
909  */
910 extern void thinlto_codegen_set_cache_entry_expiration(thinlto_code_gen_t cg,
911                                                        unsigned expiration);
912 
913 /**
914  * Sets the maximum size of the cache directory (in bytes). A value over the
915  * amount of available space on the disk will be reduced to the amount of
916  * available space. An unspecified default value will be applied. A value of 0
917  * will be ignored.
918  *
919  * \since LTO_API_VERSION=22
920  */
921 extern void thinlto_codegen_set_cache_size_bytes(thinlto_code_gen_t cg,
922                                                  unsigned max_size_bytes);
923 
924 /**
925  * Same as thinlto_codegen_set_cache_size_bytes, except the maximum size is in
926  * megabytes (2^20 bytes).
927  *
928  * \since LTO_API_VERSION=23
929  */
930 extern void
931 thinlto_codegen_set_cache_size_megabytes(thinlto_code_gen_t cg,
932                                          unsigned max_size_megabytes);
933 
934 /**
935  * Sets the maximum number of files in the cache directory. An unspecified
936  * default value will be applied. A value of 0 will be ignored.
937  *
938  * \since LTO_API_VERSION=22
939  */
940 extern void thinlto_codegen_set_cache_size_files(thinlto_code_gen_t cg,
941                                                  unsigned max_size_files);
942 
943 /**
944  * @} // endgroup LLVMCTLTO_CACHING
945  */
946 
947 LLVM_C_EXTERN_C_END
948 
949 #endif /* LLVM_C_LTO_H */
950