From e451b91356d3e642f212d7183d8c23a47fb9903f Mon Sep 17 00:00:00 2001 From: Iain Sandoe Date: Thu, 5 Sep 2019 19:27:31 +0000 Subject: [PATCH] [c-family] Backport fix for PCH / 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. There is a thinko in the current implementation, in that the decision to release resources is happening unconditionally right after the first token is extracted but before it's been checked or acted upon. This leads to the pch bug 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/ 2019-09-05 Iain Sandoe Backport from mainline 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. gcc/c-family/ 2019-09-05 Iain Sandoe Backport from mainline 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 2019-09-05 Iain Sandoe Backport from mainline. 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/ 2019-09-05 Iain Sandoe Backported from mainline 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. From-SVN: r275431 --- gcc/ChangeLog | 10 ++++++++++ gcc/c-family/ChangeLog | 9 +++++++++ gcc/c-family/c-lex.c | 7 ------- gcc/c/ChangeLog | 10 ++++++++++ gcc/c/c-parser.c | 2 ++ gcc/cp/ChangeLog | 10 ++++++++++ gcc/cp/parser.c | 5 ++++- gcc/ggc-page.c | 5 +++-- 8 files changed, 48 insertions(+), 10 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 308c44b8cc99..b11534d410a3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2019-09-05 Iain Sandoe + + Backport from mainline + 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. + 2019-09-05 Iain Sandoe Backport from mainline diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index 8c77a6ab9007..f42239755a8e 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,12 @@ +2019-09-05 Iain Sandoe + + Backport from mainline + 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. + 2019-08-30 Richard Biener Backport from mainline diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c index e1c8bdff9868..46a2f449eca3 100644 --- a/gcc/c-family/c-lex.c +++ b/gcc/c-family/c-lex.c @@ -387,7 +387,6 @@ 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; @@ -621,12 +620,6 @@ 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 394457213f78..d7c5573ac810 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,13 @@ +2019-09-05 Iain Sandoe + + Backport from mainline. + 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. + 2019-08-30 Jakub Jelinek Backported from mainline diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index 86195c53249e..339b9a0cda18 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -18214,6 +18214,8 @@ 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 e84b9a2ff744..3ffcd011b106 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,13 @@ +2019-09-05 Iain Sandoe + + Backported from mainline + 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. + 2019-09-02 Richard Biener Backport from mainline diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 7542a96dcac5..073fe434b93d 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -38232,7 +38232,10 @@ 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 da994c2faea3..4281fe6ebf9b 100644 --- a/gcc/ggc-page.c +++ b/gcc/ggc-page.c @@ -2553,6 +2553,9 @@ 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 (); @@ -2581,8 +2584,6 @@ 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, "can%'t read PCH file: %m"); for (i = 0; i < NUM_ORDERS; i++) { -- 2.47.2