From: Martin Liska Date: Thu, 9 Sep 2021 11:02:24 +0000 (+0200) Subject: gcov: make profile merging smarter X-Git-Tag: basepoints/gcc-13~3941 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=72e0c742bd01f8e7e6dcca64042b9ad7e75979de;p=thirdparty%2Fgcc.git gcov: make profile merging smarter Support merging of profiles that are built from a different .o files but belong to the same source file. Moreover, a checksum is verified during profile merging and so we can safely combine such profile. PR gcov-profile/90364 gcc/ChangeLog: * coverage.c (build_info): Emit checksum to the global variable. (build_info_type): Add new field for checksum. (coverage_obj_finish): Pass object_checksum. (coverage_init): Use 0 as checksum for .gcno files. * gcov-dump.c (dump_gcov_file): Dump also new checksum field. * gcov.c (read_graph_file): Read also checksum. * doc/invoke.texi: Document the behaviour change. libgcc/ChangeLog: * libgcov-driver.c (merge_one_data): Skip timestamp and verify checksums. (write_one_data): Write also checksum. * libgcov-util.c (read_gcda_file): Read also checksum field. * libgcov.h (struct gcov_info): Add new field. --- diff --git a/gcc/coverage.c b/gcc/coverage.c index 10d7f8366cb5..4467f1eaa5ce 100644 --- a/gcc/coverage.c +++ b/gcc/coverage.c @@ -129,16 +129,7 @@ static const char *const ctr_names[GCOV_COUNTERS] = { #undef DEF_GCOV_COUNTER /* Forward declarations. */ -static void read_counts_file (void); static tree build_var (tree, tree, int); -static void build_fn_info_type (tree, unsigned, tree); -static void build_info_type (tree, tree); -static tree build_fn_info (const struct coverage_data *, tree, tree); -static tree build_info (tree, tree); -static bool coverage_obj_init (void); -static vec *coverage_obj_fn -(vec *, tree, struct coverage_data const *); -static void coverage_obj_finish (vec *); /* Return the type node for gcov_type. */ @@ -218,6 +209,9 @@ read_counts_file (void) tag = gcov_read_unsigned (); bbg_file_stamp = crc32_unsigned (bbg_file_stamp, tag); + /* Read checksum. */ + gcov_read_unsigned (); + counts_hash = new hash_table (10); while ((tag = gcov_read_unsigned ())) { @@ -935,6 +929,12 @@ build_info_type (tree type, tree fn_info_ptr_type) DECL_CHAIN (field) = fields; fields = field; + /* Checksum. */ + field = build_decl (BUILTINS_LOCATION, FIELD_DECL, NULL_TREE, + get_gcov_unsigned_t ()); + DECL_CHAIN (field) = fields; + fields = field; + /* Filename */ field = build_decl (BUILTINS_LOCATION, FIELD_DECL, NULL_TREE, build_pointer_type (build_qualified_type @@ -977,7 +977,7 @@ build_info_type (tree type, tree fn_info_ptr_type) function info objects. */ static tree -build_info (tree info_type, tree fn_ary) +build_info (tree info_type, tree fn_ary, unsigned object_checksum) { tree info_fields = TYPE_FIELDS (info_type); tree merge_fn_type, n_funcs; @@ -996,13 +996,19 @@ build_info (tree info_type, tree fn_ary) /* next -- NULL */ CONSTRUCTOR_APPEND_ELT (v1, info_fields, null_pointer_node); info_fields = DECL_CHAIN (info_fields); - + /* stamp */ CONSTRUCTOR_APPEND_ELT (v1, info_fields, build_int_cstu (TREE_TYPE (info_fields), bbg_file_stamp)); info_fields = DECL_CHAIN (info_fields); + /* Checksum. */ + CONSTRUCTOR_APPEND_ELT (v1, info_fields, + build_int_cstu (TREE_TYPE (info_fields), + object_checksum)); + info_fields = DECL_CHAIN (info_fields); + /* Filename */ da_file_name_len = strlen (da_file_name); filename_string = build_string (da_file_name_len + 1, da_file_name); @@ -1214,7 +1220,8 @@ coverage_obj_fn (vec *ctor, tree fn, function objects from CTOR. Generate the gcov_info initializer. */ static void -coverage_obj_finish (vec *ctor) +coverage_obj_finish (vec *ctor, + unsigned object_checksum) { unsigned n_functions = vec_safe_length (ctor); tree fn_info_ary_type = build_array_type @@ -1231,7 +1238,7 @@ coverage_obj_finish (vec *ctor) varpool_node::finalize_decl (fn_info_ary); DECL_INITIAL (gcov_info_var) - = build_info (TREE_TYPE (gcov_info_var), fn_info_ary); + = build_info (TREE_TYPE (gcov_info_var), fn_info_ary, object_checksum); varpool_node::finalize_decl (gcov_info_var); } @@ -1300,7 +1307,6 @@ coverage_init (const char *filename) strcpy (da_file_name + prefix_len + len, GCOV_DATA_SUFFIX); bbg_file_stamp = local_tick; - if (flag_auto_profile) read_autofdo_file (); else if (flag_branch_probabilities) @@ -1328,6 +1334,8 @@ coverage_init (const char *filename) gcov_write_unsigned (GCOV_NOTE_MAGIC); gcov_write_unsigned (GCOV_VERSION); gcov_write_unsigned (bbg_file_stamp); + /* Use an arbitrary checksum */ + gcov_write_unsigned (0); gcov_write_string (getpwd ()); /* Do not support has_unexecuted_blocks for Ada. */ @@ -1353,14 +1361,24 @@ coverage_finish (void) cannot uniquely stamp it. If we can stamp it, libgcov will DTRT. */ unlink (da_file_name); + /* Global GCDA checksum that aggregates all functions. */ + unsigned object_checksum = 0; + if (coverage_obj_init ()) { vec *fn_ctor = NULL; struct coverage_data *fn; for (fn = functions_head; fn; fn = fn->next) - fn_ctor = coverage_obj_fn (fn_ctor, fn->fn_decl, fn); - coverage_obj_finish (fn_ctor); + { + fn_ctor = coverage_obj_fn (fn_ctor, fn->fn_decl, fn); + + object_checksum = crc32_unsigned (object_checksum, fn->ident); + object_checksum = crc32_unsigned (object_checksum, + fn->lineno_checksum); + object_checksum = crc32_unsigned (object_checksum, fn->cfg_checksum); + } + coverage_obj_finish (fn_ctor, object_checksum); } XDELETEVEC (da_file_name); diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index c4c653292474..03234c887dc0 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -14882,6 +14882,10 @@ supports locking, the data files will be correctly updated. Unless a strict ISO C dialect option is in effect, @code{fork} calls are detected and correctly handled without double counting. +Moreover, an object file can be recompiled multiple times +and the corresponding @file{.gcda} file merges as long as +the source file and the compiler options are unchanged. + @item For profile-directed optimizations, compile the source files again with the same optimization and code generation options plus diff --git a/gcc/gcov-dump.c b/gcc/gcov-dump.c index f1489fe02146..bfaf735d2ffb 100644 --- a/gcc/gcov-dump.c +++ b/gcc/gcov-dump.c @@ -206,11 +206,12 @@ dump_gcov_file (const char *filename) } /* stamp */ - { - unsigned stamp = gcov_read_unsigned (); + unsigned stamp = gcov_read_unsigned (); + printf ("%s:stamp %lu\n", filename, (unsigned long)stamp); - printf ("%s:stamp %lu\n", filename, (unsigned long)stamp); - } + /* Checksum */ + unsigned checksum = gcov_read_unsigned (); + printf ("%s:checksum %lu\n", filename, (unsigned long)checksum); if (!is_data_type) { diff --git a/gcc/gcov.c b/gcc/gcov.c index cf0a49d8c305..829e955a63ba 100644 --- a/gcc/gcov.c +++ b/gcc/gcov.c @@ -1814,6 +1814,8 @@ read_graph_file (void) bbg_file_name, v, e); } bbg_stamp = gcov_read_unsigned (); + /* Read checksum. */ + gcov_read_unsigned (); bbg_cwd = xstrdup (gcov_read_string ()); bbg_supports_has_unexecuted_blocks = gcov_read_unsigned (); @@ -2031,6 +2033,9 @@ read_count_file (void) goto cleanup; } + /* Read checksum. */ + gcov_read_unsigned (); + while ((tag = gcov_read_unsigned ())) { unsigned length = gcov_read_unsigned (); diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c index 087f71e01077..7aa97bbb06a4 100644 --- a/libgcc/libgcov-driver.c +++ b/libgcc/libgcov-driver.c @@ -260,12 +260,15 @@ merge_one_data (const char *filename, if (!gcov_version (gi_ptr, length, filename)) return -1; + /* Skip timestamp. */ + gcov_read_unsigned (); + length = gcov_read_unsigned (); - if (length != gi_ptr->stamp) + if (length != gi_ptr->checksum) { /* Read from a different compilation. Overwrite the file. */ gcov_error (GCOV_PROF_PREFIX "overwriting an existing profile data " - "with a different timestamp\n", filename); + "with a different checksum\n", filename); return 0; } @@ -495,6 +498,7 @@ write_one_data (const struct gcov_info *gi_ptr, dump_unsigned (GCOV_DATA_MAGIC, dump_fn, arg); dump_unsigned (GCOV_VERSION, dump_fn, arg); dump_unsigned (gi_ptr->stamp, dump_fn, arg); + dump_unsigned (gi_ptr->checksum, dump_fn, arg); #ifdef NEED_L_GCOV /* Generate whole program statistics. */ diff --git a/libgcc/libgcov-util.c b/libgcc/libgcov-util.c index bc7416d99bf1..766ca3559c4e 100644 --- a/libgcc/libgcov-util.c +++ b/libgcc/libgcov-util.c @@ -310,6 +310,9 @@ read_gcda_file (const char *filename) /* Read stamp. */ obj_info->stamp = gcov_read_unsigned (); + /* Read checksum. */ + obj_info->checksum = gcov_read_unsigned (); + while (1) { gcov_position_t base; diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h index f6354a7a0705..2a365c957599 100644 --- a/libgcc/libgcov.h +++ b/libgcc/libgcov.h @@ -230,6 +230,7 @@ struct gcov_info struct gcov_info *next; /* link to next, used by libgcov */ gcov_unsigned_t stamp; /* uniquifying time stamp */ + gcov_unsigned_t checksum; /* unique object checksum */ const char *filename; /* output file name */ gcov_merge_fn merge[GCOV_COUNTERS]; /* merge functions (null for