diff options
Diffstat (limited to 'gcc/collect2.c')
| -rw-r--r-- | gcc/collect2.c | 409 |
1 files changed, 396 insertions, 13 deletions
diff --git a/gcc/collect2.c b/gcc/collect2.c index 82c400bbaaf..03300f3c79b 100644 --- a/gcc/collect2.c +++ b/gcc/collect2.c @@ -184,6 +184,15 @@ static int aix64_flag; /* true if -b64 */ static int aixrtl_flag; /* true if -brtl */ #endif +enum lto_mode_d { + LTO_MODE_NONE, /* Not doing LTO. */ + LTO_MODE_LTO, /* Normal LTO. */ + LTO_MODE_WHOPR /* WHOPR. */ +}; + +/* Current LTO mode. */ +static enum lto_mode_d lto_mode = LTO_MODE_NONE; + int debug; /* true if -debug */ static int shared_obj; /* true if -shared */ @@ -193,6 +202,7 @@ static const char *o_file; /* <xxx>.o for constructor/destructor list. */ #ifdef COLLECT_EXPORT_LIST static const char *export_file; /* <xxx>.x for AIX export list. */ #endif +static char **lto_o_files; /* Output files for LTO. */ const char *ldout; /* File for ld stdout. */ const char *lderrout; /* File for ld stderr. */ static const char *output_file; /* Output file for ld. */ @@ -250,6 +260,25 @@ static struct path_prefix *libpaths[3] = {&cmdline_lib_dirs, &libpath_lib_dirs, NULL}; #endif +/* List of names of object files containing LTO information. + These are a subset of the object file names appearing on the + command line, and must be identical, in the sense of pointer + equality, with the names passed to maybe_run_lto_and_relink(). */ + +struct lto_object +{ + const char *name; /* Name of object file. */ + struct lto_object *next; /* Next in linked list. */ +}; + +struct lto_object_list +{ + struct lto_object *first; /* First list element. */ + struct lto_object *last; /* Last list element. */ +}; + +static struct lto_object_list lto_objects; + /* Special kinds of symbols that a name may denote. */ typedef enum { @@ -272,6 +301,7 @@ static void prefix_from_string (const char *, struct path_prefix *); static void do_wait (const char *, struct pex_obj *); static void fork_execute (const char *, char **); static void maybe_unlink (const char *); +static void maybe_unlink_list (char **); static void add_to_list (struct head *, const char *); static int extract_init_priority (const char *); static void sort_ids (struct head *); @@ -310,7 +340,8 @@ typedef enum { PASS_FIRST, /* without constructors */ PASS_OBJ, /* individual objects */ PASS_LIB, /* looking for shared libraries */ - PASS_SECOND /* with constructors linked in */ + PASS_SECOND, /* with constructors linked in */ + PASS_LTOINFO /* looking for objects with LTO info */ } scanpass; /* ... and which kinds of symbols are to be considered. */ @@ -363,6 +394,9 @@ collect_exit (int status) maybe_unlink (export_file); #endif + if (lto_o_files) + maybe_unlink_list (lto_o_files); + if (ldout != 0 && ldout[0]) { dump_file (ldout, stdout); @@ -472,6 +506,9 @@ handler (int signo) maybe_unlink (export_file); #endif + if (lto_o_files) + maybe_unlink_list (lto_o_files); + if (response_file) maybe_unlink (response_file); @@ -815,6 +852,247 @@ prefix_from_string (const char *p, struct path_prefix *pprefix) } free (nstore); } + +#ifdef OBJECT_FORMAT_NONE + +/* Add an entry for the object file NAME to object file list LIST. + New entries are added at the end of the list. The original pointer + value of NAME is preserved, i.e., no string copy is performed. */ + +static void +add_lto_object (struct lto_object_list *list, const char *name) +{ + struct lto_object *n = XNEW (struct lto_object); + n->name = name; + n->next = NULL; + + if (list->last) + list->last->next = n; + else + list->first = n; + + list->last = n; +} +#endif /* OBJECT_FORMAT_NONE */ + + +/* Perform a link-time recompilation and relink if any of the object + files contain LTO info. The linker command line LTO_LD_ARGV + represents the linker command that would produce a final executable + without the use of LTO. OBJECT_LST is a vector of object file names + appearing in LTO_LD_ARGV that are to be considerd for link-time + recompilation, where OBJECT is a pointer to the last valid element. + (This awkward convention avoids an impedance mismatch with the + usage of similarly-named variables in main().) The elements of + OBJECT_LST must be identical, i.e., pointer equal, to the + corresponding arguments in LTO_LD_ARGV. + + Upon entry, at least one linker run has been performed without the + use of any LTO info that might be present. Any recompilations + necessary for template instantiations have been performed, and + initializer/finalizer tables have been created if needed and + included in the linker command line LTO_LD_ARGV. If any of the + object files contain LTO info, we run the LTO back end on all such + files, and perform the final link with the LTO back end output + substituted for the LTO-optimized files. In some cases, a final + link with all link-time generated code has already been performed, + so there is no need to relink if no LTO info is found. In other + cases, our caller has not produced the final executable, and is + relying on us to perform the required link whether LTO info is + present or not. In that case, the FORCE argument should be true. + Note that the linker command line argument LTO_LD_ARGV passed into + this function may be modified in place. */ + +static void +maybe_run_lto_and_relink (char **lto_ld_argv, char **object_lst, + const char **object, bool force) +{ + const char **object_file = CONST_CAST2 (const char **, char **, object_lst); + + int num_lto_c_args = 1; /* Allow space for the terminating NULL. */ + + while (object_file < object) + { + /* If file contains LTO info, add it to the list of LTO objects. */ + scan_prog_file (*object_file++, PASS_LTOINFO, SCAN_ALL); + + /* Increment the argument count by the number of object file arguments + we will add. An upper bound suffices, so just count all of the + object files regardless of whether they contain LTO info. */ + num_lto_c_args++; + } + + if (lto_objects.first) + { + const char *opts; + char **lto_c_argv; + const char **lto_c_ptr; + const char *cp; + const char **p, **q, **r; + const char **lto_o_ptr; + struct lto_object *list; + char *lto_wrapper = getenv ("COLLECT_LTO_WRAPPER"); + struct pex_obj *pex; + const char *prog = "lto-wrapper"; + + if (!lto_wrapper) + fatal ("COLLECT_LTO_WRAPPER must be set."); + + /* There is at least one object file containing LTO info, + so we need to run the LTO back end and relink. */ + + /* Get compiler options passed down from the parent `gcc' command. + These must be passed to the LTO back end. */ + opts = getenv ("COLLECT_GCC_OPTIONS"); + + /* Increment the argument count by the number of inherited options. + Some arguments may be filtered out later. Again, an upper bound + suffices. */ + + cp = opts; + + while (cp && *cp) + { + extract_string (&cp); + num_lto_c_args++; + } + obstack_free (&temporary_obstack, temporary_firstobj); + + if (debug) + num_lto_c_args++; + + /* Increment the argument count by the number of initial + arguments added below. */ + num_lto_c_args += 9; + + lto_c_argv = (char **) xcalloc (sizeof (char *), num_lto_c_args); + lto_c_ptr = CONST_CAST2 (const char **, char **, lto_c_argv); + + *lto_c_ptr++ = lto_wrapper; + *lto_c_ptr++ = c_file_name; + + cp = opts; + + while (cp && *cp) + { + const char *s = extract_string (&cp); + + /* Pass the option or argument to the wrapper. */ + *lto_c_ptr++ = xstrdup (s); + } + obstack_free (&temporary_obstack, temporary_firstobj); + + if (debug) + *lto_c_ptr++ = xstrdup ("-debug"); + + /* Add LTO objects to the wrapper command line. */ + for (list = lto_objects.first; list; list = list->next) + *lto_c_ptr++ = list->name; + + *lto_c_ptr = NULL; + + /* Save intermediate WPA files in lto1 if debug. */ + if (debug) + putenv (xstrdup ("WPA_SAVE_LTRANS=1")); + + /* Run the LTO back end. */ + pex = collect_execute (prog, lto_c_argv, NULL, NULL, PEX_SEARCH); + { + int c; + FILE *stream; + size_t i, num_files; + char *start, *end; + + stream = pex_read_output (pex, 0); + gcc_assert (stream); + + num_files = 0; + while ((c = getc (stream)) != EOF) + { + obstack_1grow (&temporary_obstack, c); + if (c == '\n') + ++num_files; + } + + lto_o_files = XNEWVEC (char *, num_files + 1); + lto_o_files[num_files] = NULL; + start = XOBFINISH (&temporary_obstack, char *); + for (i = 0; i < num_files; ++i) + { + end = start; + while (*end != '\n') + ++end; + *end = '\0'; + + lto_o_files[i] = xstrdup (start); + + start = end + 1; + } + + obstack_free (&temporary_obstack, temporary_firstobj); + } + do_wait (prog, pex); + pex = NULL; + + /* After running the LTO back end, we will relink, substituting + the LTO output for the object files that we submitted to the + LTO. Here, we modify the linker command line for the relink. */ + p = CONST_CAST2 (const char **, char **, lto_ld_argv); + lto_o_ptr = CONST_CAST2 (const char **, char **, lto_o_files); + + while (*p != NULL) + { + for (list = lto_objects.first; list; list = list->next) + { + if (*p == list->name) /* Note test for pointer equality! */ + { + /* Excise argument from linker command line. */ + if (*lto_o_ptr) + { + /* Replace first argument with LTO output file. */ + *p++ = *lto_o_ptr++; + } + else + { + /* Move following arguments one position earlier, + overwriting the current argument. */ + q = p; + r = p + 1; + while (*r != NULL) + *q++ = *r++; + *q = NULL; + } + + /* No need to continue searching the LTO object list. */ + break; + } + } + + /* If we didn't find a match, move on to the next argument. + Otherwise, P has been set to the correct argument position + at which to continue. */ + if (!list) ++p; + } + + /* The code above assumes we will never have more lto output files than + input files. Otherwise, we need to resize lto_ld_argv. Check this + assumption. */ + if (*lto_o_ptr) + fatal ("too many lto output files"); + + /* Run the linker again, this time replacing the object files + optimized by the LTO with the temporary file generated by the LTO. */ + fork_execute ("ld", lto_ld_argv); + + maybe_unlink_list (lto_o_files); + } + else if (force) + { + /* Our caller is relying on us to do the link + even though there is no LTO back end work to be done. */ + fork_execute ("ld", lto_ld_argv); + } +} /* Main program. */ @@ -935,14 +1213,25 @@ main (int argc, char **argv) /* Parse command line early for instances of -debug. This allows the debug flag to be set before functions like find_a_file() - are called. */ + are called. We also look for the -flto or -fwhopr flag to know + what LTO mode we are in. */ { int i; + bool use_plugin = false; for (i = 1; argv[i] != NULL; i ++) { if (! strcmp (argv[i], "-debug")) debug = 1; + else if (! strcmp (argv[i], "-flto") && ! use_plugin) + lto_mode = LTO_MODE_LTO; + else if (! strcmp (argv[i], "-fwhopr") && ! use_plugin) + lto_mode = LTO_MODE_WHOPR; + else if (! strcmp (argv[i], "-plugin")) + { + use_plugin = true; + lto_mode = LTO_MODE_NONE; + } #ifdef COLLECT_EXPORT_LIST /* since -brtl, -bexport, -b64 are not position dependent also check for them here */ @@ -985,8 +1274,8 @@ main (int argc, char **argv) obstack_free (&temporary_obstack, temporary_firstobj); /* -fno-profile-arcs -fno-test-coverage -fno-branch-probabilities - -fno-exceptions -w */ - num_c_args += 5; + -fno-exceptions -w -fno-whole-program */ + num_c_args += 6; c_argv = XCNEWVEC (char *, num_c_args); c_ptr = CONST_CAST2 (const char **, char **, c_argv); @@ -1154,6 +1443,7 @@ main (int argc, char **argv) *c_ptr++ = "-fno-branch-probabilities"; *c_ptr++ = "-fno-exceptions"; *c_ptr++ = "-w"; + *c_ptr++ = "-fno-whole-program"; /* !!! When GCC calls collect2, it does not know whether it is calling collect2 or ld. @@ -1194,6 +1484,20 @@ main (int argc, char **argv) } break; + case 'f': + if (strcmp (arg, "-flto") == 0 || strcmp (arg, "-fwhopr") == 0) + { +#ifdef ENABLE_LTO + /* Do not pass LTO flag to the linker. */ + ld1--; + ld2--; +#else + error ("LTO support has not been enabled in this " + "configuration"); +#endif + } + break; + case 'l': if (first_file) { @@ -1456,6 +1760,9 @@ main (int argc, char **argv) if (export_file != 0 && export_file[0]) maybe_unlink (export_file); #endif + if (lto_mode) + maybe_run_lto_and_relink (ld1_argv, object_lst, object, false); + maybe_unlink (c_file); maybe_unlink (o_file); return 0; @@ -1498,6 +1805,9 @@ main (int argc, char **argv) if (ld1_filter == SCAN_NOTHING) do_tlink (ld1_argv, object_lst); + if (lto_mode) + maybe_run_lto_and_relink (ld1_argv, object_lst, object, false); + /* Strip now if it was requested on the command line. */ if (strip_flag) { @@ -1591,9 +1901,15 @@ main (int argc, char **argv) #ifdef COLLECT_EXPORT_LIST /* On AIX we must call tlink because of possible templates resolution. */ do_tlink (ld2_argv, object_lst); + + if (lto_mode) + maybe_run_lto_and_relink (ld2_argv, object_lst, object, false); #else /* Otherwise, simply call ld because tlink is already done. */ - fork_execute ("ld", ld2_argv); + if (lto_mode) + maybe_run_lto_and_relink (ld2_argv, object_lst, object, true); + else + fork_execute ("ld", ld2_argv); /* Let scan_prog_file do any final mods (OSF/rose needs this for constructors/destructors in shared libraries. */ @@ -1661,7 +1977,7 @@ do_wait (const char *prog, struct pex_obj *pex) struct pex_obj * collect_execute (const char *prog, char **argv, const char *outname, - const char *errname) + const char *errname, int flags) { struct pex_obj *pex; const char *errmsg; @@ -1737,7 +2053,7 @@ collect_execute (const char *prog, char **argv, const char *outname, if (pex == NULL) fatal_perror ("pex_init failed"); - errmsg = pex_run (pex, PEX_LAST | PEX_SEARCH, argv[0], argv, outname, + errmsg = pex_run (pex, flags, argv[0], argv, outname, errname, &err); if (errmsg != NULL) { @@ -1761,7 +2077,7 @@ fork_execute (const char *prog, char **argv) { struct pex_obj *pex; - pex = collect_execute (prog, argv, NULL, NULL); + pex = collect_execute (prog, argv, NULL, NULL, PEX_LAST | PEX_SEARCH); do_wait (prog, pex); } @@ -1776,6 +2092,17 @@ maybe_unlink (const char *file) notice ("[Leaving %s]\n", file); } +/* Call maybe_unlink on the NULL-terminated list, FILE_LIST. */ + +static void +maybe_unlink_list (char **file_list) +{ + char **tmp = file_list; + + while (*tmp) + maybe_unlink (*(tmp++)); +} + static long sequence_number = 0; @@ -2170,6 +2497,25 @@ write_aix_file (FILE *stream, struct id *list) #ifdef OBJECT_FORMAT_NONE +/* Check to make sure the file is an ELF file. LTO objects must + be in ELF format. */ + +static bool +is_elf (const char *prog_name) +{ + FILE *f; + char buf[4]; + static char magic[4] = { 0x7f, 'E', 'L', 'F' }; + + f = fopen (prog_name, "r"); + if (f == NULL) + return false; + if (fread (buf, sizeof (buf), 1, f) != 1) + buf[0] = 0; + fclose (f); + return memcmp (buf, magic, sizeof (magic)) == 0; +} + /* Generic version to scan the name list of the loaded program for the symbols g++ uses for static constructors and destructors. */ @@ -2189,10 +2535,17 @@ scan_prog_file (const char *prog_name, scanpass which_pass, int err; char *p, buf[1024]; FILE *inf; + int found_lto = 0; if (which_pass == PASS_SECOND) return; + /* LTO objects must be in ELF format. This check prevents + us from accepting an archive containing LTO objects, which + gcc cannnot currently handle. */ + if (which_pass == PASS_LTOINFO && !is_elf (prog_name)) + return; + /* If we do not have an `nm', complain. */ if (nm_file_name == 0) fatal ("cannot find 'nm'"); @@ -2223,7 +2576,8 @@ scan_prog_file (const char *prog_name, scanpass which_pass, if (pex == NULL) fatal_perror ("pex_init failed"); - errmsg = pex_run (pex, 0, nm_file_name, real_nm_argv, NULL, NULL, &err); + errmsg = pex_run (pex, 0, nm_file_name, real_nm_argv, NULL, HOST_BIT_BUCKET, + &err); if (errmsg != NULL) { if (err != 0) @@ -2245,7 +2599,12 @@ scan_prog_file (const char *prog_name, scanpass which_pass, fatal_perror ("can't open nm output"); if (debug) - fprintf (stderr, "\nnm output with constructors/destructors.\n"); + { + if (which_pass == PASS_LTOINFO) + fprintf (stderr, "\nnm output with LTO info marker symbol.\n"); + else + fprintf (stderr, "\nnm output with constructors/destructors.\n"); + } /* Read each line of nm output. */ while (fgets (buf, sizeof buf, inf) != (char *) 0) @@ -2253,6 +2612,33 @@ scan_prog_file (const char *prog_name, scanpass which_pass, int ch, ch2; char *name, *end; + if (debug) + fprintf (stderr, "\t%s\n", buf); + + if (which_pass == PASS_LTOINFO) + { + if (found_lto) + continue; + + /* Look for the LTO info marker symbol, and add filename to + the LTO objects list if found. */ + for (p = buf; (ch = *p) != '\0' && ch != '\n'; p++) + if (ch == ' ' + && (strncmp (p +1 , "gnu_lto_v1", 10) == 0) + && ISSPACE( p[11])) + { + add_lto_object (<o_objects, prog_name); + + /* We need to read all the input, so we can't just + return here. But we can avoid useless work. */ + found_lto = 1; + + break; + } + + continue; + } + /* If it contains a constructor or destructor name, add the name to the appropriate list unless this is a kind of symbol we're not supposed to even consider. */ @@ -2319,9 +2705,6 @@ scan_prog_file (const char *prog_name, scanpass which_pass, default: /* not a constructor or destructor */ continue; } - - if (debug) - fprintf (stderr, "\t%s\n", buf); } if (debug) |