From 22f8849d06019e925eb8669274a03daf02e71cc6 Mon Sep 17 00:00:00 2001 From: Iain Sandoe Date: Fri, 23 Aug 2019 12:41:39 +0000 Subject: [PATCH] [PATCH, c-family] Fix a PCH thinko (and thus PR61250). When we are parsing a source file, the very first token might be a PRAGMA_GCC_PCH_PREPROCESS. This indicates that we are going read in a PCH file (named as the value of the pragma). If we don't see this pragma, then we know that it's OK to release any resources that the host might have set aside for the PCH file. This fixes a thinko in the current implementation, in that the decision to release resources was happening unconditionally right after the first token is extracted but before it's been checked or acted upon. This leads to the pch bug (seen on Darwin), because we actually do release resources - which are subsequently (reasonably) assumed to be available when reading a PCH file. We then get random crashes or hangs depending on the interaction between unmmap and malloc. The bug is present everywhere but doesn't show on (say) Linux, since the release of PCH resources is a NOP there. This effects all the c-family front ends, because they all use c_lex_with_flags () to implement this. The solution is to check for the PRAGMA_GCC_PCH_PREPROCESS and only call c_common_no_more_pch () when that is not the first token. A secondary effect of the collection is that the name of the PCH file can be collected during the ggc_pch_read() reset of state. Therefore we should issue any diagnostic that might name the file before the collections are triggered. gcc/c-family/ 2019-08-23 Iain Sandoe PR pch/61250 * c-lex.c (c_lex_with_flags): Don't call c_common_no_more_pch () from here. gcc/c/ 2019-08-23 Iain Sandoe PR pch/61250 * c-parser.c (c_parse_file): Call c_common_no_more_pch () after determining that the first token is not PRAGMA_GCC_PCH_PREPROCESS. gcc/cp/ 2019-08-23 Iain Sandoe PR pch/61250 * parser.c (cp_parser_initial_pragma): Call c_common_no_more_pch () after determining that the first token is not PRAGMA_GCC_PCH_PREPROCESS. gcc/ 2019-08-23 Iain Sandoe PR pch/61250 * ggc-page.c (ggc_pch_read): Read the ggc_pch_ondisk structure and issue any diagnostics needed before collecting the pre-PCH state. From-SVN: r274856 --- gcc/ChangeLog | 7 +++++++ gcc/c-family/ChangeLog | 6 ++++++ gcc/c-family/c-lex.c | 7 ------- gcc/c/ChangeLog | 7 +++++++ gcc/c/c-parser.c | 2 ++ gcc/cp/ChangeLog | 7 +++++++ gcc/cp/parser.c | 5 ++++- gcc/ggc-page.c | 5 +++-- 8 files changed, 36 insertions(+), 10 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 62aebf25ddc..86669dd5cf3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2019-08-23 Iain Sandoe + + PR pch/61250 + * ggc-page.c (ggc_pch_read): Read the ggc_pch_ondisk structure + and issue any diagnostics needed before collecting the pre-PCH + state. + 2019-08-23 Jakub Jelinek PR middle-end/91283 diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index b8920f1c18d..2ab1c98b260 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,9 @@ +2019-08-23 Iain Sandoe + + PR pch/61250 + * c-lex.c (c_lex_with_flags): Don't call + c_common_no_more_pch () from here. + 2019-08-23 Jakub Jelinek PR middle-end/91283 diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c index 851fd704e5d..e3c602fbb8d 100644 --- a/gcc/c-family/c-lex.c +++ b/gcc/c-family/c-lex.c @@ -394,7 +394,6 @@ enum cpp_ttype c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags, int lex_flags) { - static bool no_more_pch; const cpp_token *tok; enum cpp_ttype type; unsigned char add_flags = 0; @@ -628,12 +627,6 @@ c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags, if (cpp_flags) *cpp_flags = tok->flags | add_flags; - if (!no_more_pch) - { - no_more_pch = true; - c_common_no_more_pch (); - } - timevar_pop (TV_CPP); return type; diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog index 0b3dc74f50f..b7b45f504a1 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,10 @@ +2019-08-23 Iain Sandoe + + PR pch/61250 + * c-parser.c (c_parse_file): Call c_common_no_more_pch () + after determining that the first token is not + PRAGMA_GCC_PCH_PREPROCESS. + 2019-08-22 Eric Botcazou * c-parser.c (c_parser_declaration_or_fndef): Set DECL_ARGUMENTS of a diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index 7397f536032..6070502deb5 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -20263,6 +20263,8 @@ c_parse_file (void) if (c_parser_peek_token (&tparser)->pragma_kind == PRAGMA_GCC_PCH_PREPROCESS) c_parser_pragma_pch_preprocess (&tparser); + else + c_common_no_more_pch (); the_parser = ggc_alloc (); *the_parser = tparser; diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index d2b96231fd0..f014423ca00 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2019-08-23 Iain Sandoe + + PR pch/61250 + * parser.c (cp_parser_initial_pragma): Call c_common_no_more_pch () + after determining that the first token is not + PRAGMA_GCC_PCH_PREPROCESS. + 2019-08-22 Marek Polacek PR c++/91304 - prefix attributes ignored in condition. diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index b410a6c030f..504f77a4908 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -41357,7 +41357,10 @@ cp_parser_initial_pragma (cp_token *first_token) cp_lexer_get_preprocessor_token (NULL, first_token); if (cp_parser_pragma_kind (first_token) != PRAGMA_GCC_PCH_PREPROCESS) - return; + { + c_common_no_more_pch (); + return; + } cp_lexer_get_preprocessor_token (NULL, first_token); if (first_token->type == CPP_STRING) diff --git a/gcc/ggc-page.c b/gcc/ggc-page.c index a2736bc1dfa..220f20c5cfe 100644 --- a/gcc/ggc-page.c +++ b/gcc/ggc-page.c @@ -2556,6 +2556,9 @@ ggc_pch_read (FILE *f, void *addr) count_old_page_tables = G.by_depth_in_use; + if (fread (&d, sizeof (d), 1, f) != 1) + fatal_error (input_location, "cannot read PCH file: %m"); + /* We've just read in a PCH file. So, every object that used to be allocated is now free. */ clear_marks (); @@ -2584,8 +2587,6 @@ ggc_pch_read (FILE *f, void *addr) /* Allocate the appropriate page-table entries for the pages read from the PCH file. */ - if (fread (&d, sizeof (d), 1, f) != 1) - fatal_error (input_location, "cannot read PCH file: %m"); for (i = 0; i < NUM_ORDERS; i++) { -- 2.30.2