From f3b957ea8b9dadfb1ed30f24f463529684b7a36a Mon Sep 17 00:00:00 2001 From: Lewis Hyatt Date: Fri, 14 Oct 2022 13:52:12 -0400 Subject: pch: Fix streaming of strings with embedded null bytes When a GTY'ed struct is streamed to PCH, any plain char* pointers it contains (whether they live in GC-controlled memory or not) will be marked for PCH output by the routine gt_pch_note_object in ggc-common.cc. This routine special-cases plain char* strings, and in particular it uses strlen() to get their length. Thus it does not handle strings with embedded null bytes, but it is possible for something PCH cares about (such as a string literal token in a macro definition) to contain such embedded nulls. To fix that up, add a new GTY option "string_length" so that gt_pch_note_object can be informed the actual length it ought to use, and use it in the relevant libcpp structs (cpp_string and ht_identifier) accordingly. gcc/ChangeLog: * gengtype.cc (output_escaped_param): Add missing const. (get_string_option): Add missing check for option type. (walk_type): Support new "string_length" GTY option. (write_types_process_field): Likewise. * ggc-common.cc (gt_pch_note_object): Add optional length argument. * ggc.h (gt_pch_note_object): Adjust prototype for new argument. (gt_pch_n_S2): Declare... * stringpool.cc (gt_pch_n_S2): ...new function. * doc/gty.texi: Document new GTY((string_length)) option. libcpp/ChangeLog: * include/cpplib.h (struct cpp_string): Use new "string_length" GTY. * include/symtab.h (struct ht_identifier): Likewise. gcc/testsuite/ChangeLog: * g++.dg/pch/pch-string-nulls.C: New test. * g++.dg/pch/pch-string-nulls.Hs: New test. --- libcpp/include/cpplib.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'libcpp/include/cpplib.h') diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h index d5ef12a..1d34c00 100644 --- a/libcpp/include/cpplib.h +++ b/libcpp/include/cpplib.h @@ -179,7 +179,11 @@ enum c_lang {CLK_GNUC89 = 0, CLK_GNUC99, CLK_GNUC11, CLK_GNUC17, CLK_GNUC2X, /* Payload of a NUMBER, STRING, CHAR or COMMENT token. */ struct GTY(()) cpp_string { unsigned int len; - const unsigned char *text; + + /* TEXT is always null terminated (terminator not included in len); but this + GTY markup arranges that PCH streaming works properly even if there is a + null byte in the middle of the string. */ + const unsigned char * GTY((string_length ("1 + %h.len"))) text; }; /* Flags for the cpp_token structure. */ -- cgit v1.1