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 29
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  * This function can be used by the linker to check if a given module has
317  * any constructor or destructor functions.
318  *
319  * Returns true if the module has either the @llvm.global_ctors or the
320  * @llvm.global_dtors symbol. Otherwise returns false.
321  *
322  * \since LTO_API_VERSION=29
323  */
324 extern lto_bool_t lto_module_has_ctor_dtor(lto_module_t mod);
325 /**
326  * Diagnostic severity.
327  *
328  * \since LTO_API_VERSION=7
329  */
330 typedef enum {
331   LTO_DS_ERROR = 0,
332   LTO_DS_WARNING = 1,
333   LTO_DS_REMARK = 3, // Added in LTO_API_VERSION=10.
334   LTO_DS_NOTE = 2
335 } lto_codegen_diagnostic_severity_t;
336 
337 /**
338  * Diagnostic handler type.
339  * \p severity defines the severity.
340  * \p diag is the actual diagnostic.
341  * The diagnostic is not prefixed by any of severity keyword, e.g., 'error: '.
342  * \p ctxt is used to pass the context set with the diagnostic handler.
343  *
344  * \since LTO_API_VERSION=7
345  */
346 typedef void (*lto_diagnostic_handler_t)(
347     lto_codegen_diagnostic_severity_t severity, const char *diag, void *ctxt);
348 
349 /**
350  * Set a diagnostic handler and the related context (void *).
351  * This is more general than lto_get_error_message, as the diagnostic handler
352  * can be called at anytime within lto.
353  *
354  * \since LTO_API_VERSION=7
355  */
356 extern void lto_codegen_set_diagnostic_handler(lto_code_gen_t,
357                                                lto_diagnostic_handler_t,
358                                                void *);
359 
360 /**
361  * Instantiates a code generator.
362  * Returns NULL on error (check lto_get_error_message() for details).
363  *
364  * All modules added using \a lto_codegen_add_module() must have been created
365  * in the same context as the codegen.
366  *
367  * \since prior to LTO_API_VERSION=3
368  */
369 extern lto_code_gen_t
370 lto_codegen_create(void);
371 
372 /**
373  * Instantiate a code generator in its own context.
374  *
375  * Instantiates a code generator in its own context.  Modules added via \a
376  * lto_codegen_add_module() must have all been created in the same context,
377  * using \a lto_module_create_in_codegen_context().
378  *
379  * \since LTO_API_VERSION=11
380  */
381 extern lto_code_gen_t
382 lto_codegen_create_in_local_context(void);
383 
384 /**
385  * Frees all code generator and all memory it internally allocated.
386  * Upon return the lto_code_gen_t is no longer valid.
387  *
388  * \since prior to LTO_API_VERSION=3
389  */
390 extern void
391 lto_codegen_dispose(lto_code_gen_t);
392 
393 /**
394  * Add an object module to the set of modules for which code will be generated.
395  * Returns true on error (check lto_get_error_message() for details).
396  *
397  * \c cg and \c mod must both be in the same context.  See \a
398  * lto_codegen_create_in_local_context() and \a
399  * lto_module_create_in_codegen_context().
400  *
401  * \since prior to LTO_API_VERSION=3
402  */
403 extern lto_bool_t
404 lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod);
405 
406 /**
407  * Sets the object module for code generation. This will transfer the ownership
408  * of the module to the code generator.
409  *
410  * \c cg and \c mod must both be in the same context.
411  *
412  * \since LTO_API_VERSION=13
413  */
414 extern void
415 lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod);
416 
417 /**
418  * Sets if debug info should be generated.
419  * Returns true on error (check lto_get_error_message() for details).
420  *
421  * \since prior to LTO_API_VERSION=3
422  */
423 extern lto_bool_t
424 lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model);
425 
426 /**
427  * Sets which PIC code model to generated.
428  * Returns true on error (check lto_get_error_message() for details).
429  *
430  * \since prior to LTO_API_VERSION=3
431  */
432 extern lto_bool_t
433 lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model);
434 
435 /**
436  * Sets the cpu to generate code for.
437  *
438  * \since LTO_API_VERSION=4
439  */
440 extern void
441 lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu);
442 
443 /**
444  * Sets the location of the assembler tool to run. If not set, libLTO
445  * will use gcc to invoke the assembler.
446  *
447  * \since LTO_API_VERSION=3
448  */
449 extern void
450 lto_codegen_set_assembler_path(lto_code_gen_t cg, const char* path);
451 
452 /**
453  * Sets extra arguments that libLTO should pass to the assembler.
454  *
455  * \since LTO_API_VERSION=4
456  */
457 extern void
458 lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
459                                int nargs);
460 
461 /**
462  * Adds to a list of all global symbols that must exist in the final generated
463  * code. If a function is not listed there, it might be inlined into every usage
464  * and optimized away.
465  *
466  * \since prior to LTO_API_VERSION=3
467  */
468 extern void
469 lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg, const char* symbol);
470 
471 /**
472  * Writes a new object file at the specified path that contains the
473  * merged contents of all modules added so far.
474  * Returns true on error (check lto_get_error_message() for details).
475  *
476  * \since LTO_API_VERSION=5
477  */
478 extern lto_bool_t
479 lto_codegen_write_merged_modules(lto_code_gen_t cg, const char* path);
480 
481 /**
482  * Generates code for all added modules into one native object file.
483  * This calls lto_codegen_optimize then lto_codegen_compile_optimized.
484  *
485  * On success returns a pointer to a generated mach-o/ELF buffer and
486  * length set to the buffer size.  The buffer is owned by the
487  * lto_code_gen_t and will be freed when lto_codegen_dispose()
488  * is called, or lto_codegen_compile() is called again.
489  * On failure, returns NULL (check lto_get_error_message() for details).
490  *
491  * \since prior to LTO_API_VERSION=3
492  */
493 extern const void*
494 lto_codegen_compile(lto_code_gen_t cg, size_t* length);
495 
496 /**
497  * Generates code for all added modules into one native object file.
498  * This calls lto_codegen_optimize then lto_codegen_compile_optimized (instead
499  * of returning a generated mach-o/ELF buffer, it writes to a file).
500  *
501  * The name of the file is written to name. Returns true on error.
502  *
503  * \since LTO_API_VERSION=5
504  */
505 extern lto_bool_t
506 lto_codegen_compile_to_file(lto_code_gen_t cg, const char** name);
507 
508 /**
509  * Runs optimization for the merged module. Returns true on error.
510  *
511  * \since LTO_API_VERSION=12
512  */
513 extern lto_bool_t
514 lto_codegen_optimize(lto_code_gen_t cg);
515 
516 /**
517  * Generates code for the optimized merged module into one native object file.
518  * It will not run any IR optimizations on the merged module.
519  *
520  * On success returns a pointer to a generated mach-o/ELF buffer and length set
521  * to the buffer size.  The buffer is owned by the lto_code_gen_t and will be
522  * freed when lto_codegen_dispose() is called, or
523  * lto_codegen_compile_optimized() is called again. On failure, returns NULL
524  * (check lto_get_error_message() for details).
525  *
526  * \since LTO_API_VERSION=12
527  */
528 extern const void*
529 lto_codegen_compile_optimized(lto_code_gen_t cg, size_t* length);
530 
531 /**
532  * Returns the runtime API version.
533  *
534  * \since LTO_API_VERSION=12
535  */
536 extern unsigned int
537 lto_api_version(void);
538 
539 /**
540  * Parses options immediately, making them available as early as possible. For
541  * example during executing codegen::InitTargetOptionsFromCodeGenFlags. Since
542  * parsing shud only happen once, only one of lto_codegen_debug_options or
543  * lto_set_debug_options should be called.
544  *
545  * This function takes one or more options separated by spaces.
546  * Warning: passing file paths through this function may confuse the argument
547  * parser if the paths contain spaces.
548  *
549  * \since LTO_API_VERSION=28
550  */
551 extern void lto_set_debug_options(const char *const *options, int number);
552 
553 /**
554  * Sets options to help debug codegen bugs. Since parsing shud only happen once,
555  * only one of lto_codegen_debug_options or lto_set_debug_options
556  * should be called.
557  *
558  * This function takes one or more options separated by spaces.
559  * Warning: passing file paths through this function may confuse the argument
560  * parser if the paths contain spaces.
561  *
562  * \since prior to LTO_API_VERSION=3
563  */
564 extern void
565 lto_codegen_debug_options(lto_code_gen_t cg, const char *);
566 
567 /**
568  * Same as the previous function, but takes every option separately through an
569  * array.
570  *
571  * \since prior to LTO_API_VERSION=26
572  */
573 extern void lto_codegen_debug_options_array(lto_code_gen_t cg,
574                                             const char *const *, int number);
575 
576 /**
577  * Initializes LLVM disassemblers.
578  * FIXME: This doesn't really belong here.
579  *
580  * \since LTO_API_VERSION=5
581  */
582 extern void
583 lto_initialize_disassembler(void);
584 
585 /**
586  * Sets if we should run internalize pass during optimization and code
587  * generation.
588  *
589  * \since LTO_API_VERSION=14
590  */
591 extern void
592 lto_codegen_set_should_internalize(lto_code_gen_t cg,
593                                    lto_bool_t ShouldInternalize);
594 
595 /**
596  * Set whether to embed uselists in bitcode.
597  *
598  * Sets whether \a lto_codegen_write_merged_modules() should embed uselists in
599  * output bitcode.  This should be turned on for all -save-temps output.
600  *
601  * \since LTO_API_VERSION=15
602  */
603 extern void
604 lto_codegen_set_should_embed_uselists(lto_code_gen_t cg,
605                                       lto_bool_t ShouldEmbedUselists);
606 
607 /** Opaque reference to an LTO input file */
608 typedef struct LLVMOpaqueLTOInput *lto_input_t;
609 
610 /**
611   * Creates an LTO input file from a buffer. The path
612   * argument is used for diagnotics as this function
613   * otherwise does not know which file the given buffer
614   * is associated with.
615   *
616   * \since LTO_API_VERSION=24
617   */
618 extern lto_input_t lto_input_create(const void *buffer,
619                                     size_t buffer_size,
620                                     const char *path);
621 
622 /**
623   * Frees all memory internally allocated by the LTO input file.
624   * Upon return the lto_module_t is no longer valid.
625   *
626   * \since LTO_API_VERSION=24
627   */
628 extern void lto_input_dispose(lto_input_t input);
629 
630 /**
631   * Returns the number of dependent library specifiers
632   * for the given LTO input file.
633   *
634   * \since LTO_API_VERSION=24
635   */
636 extern unsigned lto_input_get_num_dependent_libraries(lto_input_t input);
637 
638 /**
639   * Returns the ith dependent library specifier
640   * for the given LTO input file. The returned
641   * string is not null-terminated.
642   *
643   * \since LTO_API_VERSION=24
644   */
645 extern const char * lto_input_get_dependent_library(lto_input_t input,
646                                                     size_t index,
647                                                     size_t *size);
648 
649 /**
650  * Returns the list of libcall symbols that can be generated by LTO
651  * that might not be visible from the symbol table of bitcode files.
652  *
653  * \since prior to LTO_API_VERSION=25
654  */
655 extern const char *const *lto_runtime_lib_symbols_list(size_t *size);
656 
657 /**
658  * @} // endgoup LLVMCLTO
659  * @defgroup LLVMCTLTO ThinLTO
660  * @ingroup LLVMC
661  *
662  * @{
663  */
664 
665 /**
666  * Type to wrap a single object returned by ThinLTO.
667  *
668  * \since LTO_API_VERSION=18
669  */
670 typedef struct {
671   const char *Buffer;
672   size_t Size;
673 } LTOObjectBuffer;
674 
675 /**
676  * Instantiates a ThinLTO code generator.
677  * Returns NULL on error (check lto_get_error_message() for details).
678  *
679  *
680  * The ThinLTOCodeGenerator is not intended to be reuse for multiple
681  * compilation: the model is that the client adds modules to the generator and
682  * ask to perform the ThinLTO optimizations / codegen, and finally destroys the
683  * codegenerator.
684  *
685  * \since LTO_API_VERSION=18
686  */
687 extern thinlto_code_gen_t thinlto_create_codegen(void);
688 
689 /**
690  * Frees the generator and all memory it internally allocated.
691  * Upon return the thinlto_code_gen_t is no longer valid.
692  *
693  * \since LTO_API_VERSION=18
694  */
695 extern void thinlto_codegen_dispose(thinlto_code_gen_t cg);
696 
697 /**
698  * Add a module to a ThinLTO code generator. Identifier has to be unique among
699  * all the modules in a code generator. The data buffer stays owned by the
700  * client, and is expected to be available for the entire lifetime of the
701  * thinlto_code_gen_t it is added to.
702  *
703  * On failure, returns NULL (check lto_get_error_message() for details).
704  *
705  *
706  * \since LTO_API_VERSION=18
707  */
708 extern void thinlto_codegen_add_module(thinlto_code_gen_t cg,
709                                        const char *identifier, const char *data,
710                                        int length);
711 
712 /**
713  * Optimize and codegen all the modules added to the codegenerator using
714  * ThinLTO. Resulting objects are accessible using thinlto_module_get_object().
715  *
716  * \since LTO_API_VERSION=18
717  */
718 extern void thinlto_codegen_process(thinlto_code_gen_t cg);
719 
720 /**
721  * Returns the number of object files produced by the ThinLTO CodeGenerator.
722  *
723  * It usually matches the number of input files, but this is not a guarantee of
724  * the API and may change in future implementation, so the client should not
725  * assume it.
726  *
727  * \since LTO_API_VERSION=18
728  */
729 extern unsigned int thinlto_module_get_num_objects(thinlto_code_gen_t cg);
730 
731 /**
732  * Returns a reference to the ith object file produced by the ThinLTO
733  * CodeGenerator.
734  *
735  * Client should use \p thinlto_module_get_num_objects() to get the number of
736  * available objects.
737  *
738  * \since LTO_API_VERSION=18
739  */
740 extern LTOObjectBuffer thinlto_module_get_object(thinlto_code_gen_t cg,
741                                                  unsigned int index);
742 
743 /**
744  * Returns the number of object files produced by the ThinLTO CodeGenerator.
745  *
746  * It usually matches the number of input files, but this is not a guarantee of
747  * the API and may change in future implementation, so the client should not
748  * assume it.
749  *
750  * \since LTO_API_VERSION=21
751  */
752 unsigned int thinlto_module_get_num_object_files(thinlto_code_gen_t cg);
753 
754 /**
755  * Returns the path to the ith object file produced by the ThinLTO
756  * CodeGenerator.
757  *
758  * Client should use \p thinlto_module_get_num_object_files() to get the number
759  * of available objects.
760  *
761  * \since LTO_API_VERSION=21
762  */
763 const char *thinlto_module_get_object_file(thinlto_code_gen_t cg,
764                                            unsigned int index);
765 
766 /**
767  * Sets which PIC code model to generate.
768  * Returns true on error (check lto_get_error_message() for details).
769  *
770  * \since LTO_API_VERSION=18
771  */
772 extern lto_bool_t thinlto_codegen_set_pic_model(thinlto_code_gen_t cg,
773                                                 lto_codegen_model);
774 
775 /**
776  * Sets the path to a directory to use as a storage for temporary bitcode files.
777  * The intention is to make the bitcode files available for debugging at various
778  * stage of the pipeline.
779  *
780  * \since LTO_API_VERSION=18
781  */
782 extern void thinlto_codegen_set_savetemps_dir(thinlto_code_gen_t cg,
783                                               const char *save_temps_dir);
784 
785 /**
786  * Set the path to a directory where to save generated object files. This
787  * path can be used by a linker to request on-disk files instead of in-memory
788  * buffers. When set, results are available through
789  * thinlto_module_get_object_file() instead of thinlto_module_get_object().
790  *
791  * \since LTO_API_VERSION=21
792  */
793 void thinlto_set_generated_objects_dir(thinlto_code_gen_t cg,
794                                        const char *save_temps_dir);
795 
796 /**
797  * Sets the cpu to generate code for.
798  *
799  * \since LTO_API_VERSION=18
800  */
801 extern void thinlto_codegen_set_cpu(thinlto_code_gen_t cg, const char *cpu);
802 
803 /**
804  * Disable CodeGen, only run the stages till codegen and stop. The output will
805  * be bitcode.
806  *
807  * \since LTO_API_VERSION=19
808  */
809 extern void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
810                                             lto_bool_t disable);
811 
812 /**
813  * Perform CodeGen only: disable all other stages.
814  *
815  * \since LTO_API_VERSION=19
816  */
817 extern void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
818                                              lto_bool_t codegen_only);
819 
820 /**
821  * Parse -mllvm style debug options.
822  *
823  * \since LTO_API_VERSION=18
824  */
825 extern void thinlto_debug_options(const char *const *options, int number);
826 
827 /**
828  * Test if a module has support for ThinLTO linking.
829  *
830  * \since LTO_API_VERSION=18
831  */
832 extern lto_bool_t lto_module_is_thinlto(lto_module_t mod);
833 
834 /**
835  * Adds a symbol to the list of global symbols that must exist in the final
836  * generated code. If a function is not listed there, it might be inlined into
837  * every usage and optimized away. For every single module, the functions
838  * referenced from code outside of the ThinLTO modules need to be added here.
839  *
840  * \since LTO_API_VERSION=18
841  */
842 extern void thinlto_codegen_add_must_preserve_symbol(thinlto_code_gen_t cg,
843                                                      const char *name,
844                                                      int length);
845 
846 /**
847  * Adds a symbol to the list of global symbols that are cross-referenced between
848  * ThinLTO files. If the ThinLTO CodeGenerator can ensure that every
849  * references from a ThinLTO module to this symbol is optimized away, then
850  * the symbol can be discarded.
851  *
852  * \since LTO_API_VERSION=18
853  */
854 extern void thinlto_codegen_add_cross_referenced_symbol(thinlto_code_gen_t cg,
855                                                         const char *name,
856                                                         int length);
857 
858 /**
859  * @} // endgoup LLVMCTLTO
860  * @defgroup LLVMCTLTO_CACHING ThinLTO Cache Control
861  * @ingroup LLVMCTLTO
862  *
863  * These entry points control the ThinLTO cache. The cache is intended to
864  * support incremental builds, and thus needs to be persistent across builds.
865  * The client enables the cache by supplying a path to an existing directory.
866  * The code generator will use this to store objects files that may be reused
867  * during a subsequent build.
868  * To avoid filling the disk space, a few knobs are provided:
869  *  - The pruning interval limits the frequency at which the garbage collector
870  *    will try to scan the cache directory to prune expired entries.
871  *    Setting to a negative number disables the pruning.
872  *  - The pruning expiration time indicates to the garbage collector how old an
873  *    entry needs to be to be removed.
874  *  - Finally, the garbage collector can be instructed to prune the cache until
875  *    the occupied space goes below a threshold.
876  * @{
877  */
878 
879 /**
880  * Sets the path to a directory to use as a cache storage for incremental build.
881  * Setting this activates caching.
882  *
883  * \since LTO_API_VERSION=18
884  */
885 extern void thinlto_codegen_set_cache_dir(thinlto_code_gen_t cg,
886                                           const char *cache_dir);
887 
888 /**
889  * Sets the cache pruning interval (in seconds). A negative value disables the
890  * pruning. An unspecified default value will be applied, and a value of 0 will
891  * force prunning to occur.
892  *
893  * \since LTO_API_VERSION=18
894  */
895 extern void thinlto_codegen_set_cache_pruning_interval(thinlto_code_gen_t cg,
896                                                        int interval);
897 
898 /**
899  * Sets the maximum cache size that can be persistent across build, in terms of
900  * percentage of the available space on the disk. Set to 100 to indicate
901  * no limit, 50 to indicate that the cache size will not be left over half the
902  * available space. A value over 100 will be reduced to 100, a value of 0 will
903  * be ignored. An unspecified default value will be applied.
904  *
905  * The formula looks like:
906  *  AvailableSpace = FreeSpace + ExistingCacheSize
907  *  NewCacheSize = AvailableSpace * P/100
908  *
909  * \since LTO_API_VERSION=18
910  */
911 extern void thinlto_codegen_set_final_cache_size_relative_to_available_space(
912     thinlto_code_gen_t cg, unsigned percentage);
913 
914 /**
915  * Sets the expiration (in seconds) for an entry in the cache. An unspecified
916  * default value will be applied. A value of 0 will be ignored.
917  *
918  * \since LTO_API_VERSION=18
919  */
920 extern void thinlto_codegen_set_cache_entry_expiration(thinlto_code_gen_t cg,
921                                                        unsigned expiration);
922 
923 /**
924  * Sets the maximum size of the cache directory (in bytes). A value over the
925  * amount of available space on the disk will be reduced to the amount of
926  * available space. An unspecified default value will be applied. A value of 0
927  * will be ignored.
928  *
929  * \since LTO_API_VERSION=22
930  */
931 extern void thinlto_codegen_set_cache_size_bytes(thinlto_code_gen_t cg,
932                                                  unsigned max_size_bytes);
933 
934 /**
935  * Same as thinlto_codegen_set_cache_size_bytes, except the maximum size is in
936  * megabytes (2^20 bytes).
937  *
938  * \since LTO_API_VERSION=23
939  */
940 extern void
941 thinlto_codegen_set_cache_size_megabytes(thinlto_code_gen_t cg,
942                                          unsigned max_size_megabytes);
943 
944 /**
945  * Sets the maximum number of files in the cache directory. An unspecified
946  * default value will be applied. A value of 0 will be ignored.
947  *
948  * \since LTO_API_VERSION=22
949  */
950 extern void thinlto_codegen_set_cache_size_files(thinlto_code_gen_t cg,
951                                                  unsigned max_size_files);
952 
953 /**
954  * @} // endgroup LLVMCTLTO_CACHING
955  */
956 
957 LLVM_C_EXTERN_C_END
958 
959 #endif /* LLVM_C_LTO_H */
960