Fix -D_GLIBCXX_DEBUG gdb-add-index regression

Fedora Rawhide started to use -D_GLIBCXX_DEBUG which made gdb-add-index
failing:
	gdb: Out-of-bounds vector access while running gdb-add-index
	https://bugzilla.redhat.com/show_bug.cgi?id=1540559

/usr/include/c++/7/debug/safe_iterator.h:270:
Error: attempt to dereference a past-the-end iterator.
Objects involved in the operation:
    iterator "this" @ 0x0x7fffffffcb90 {
      type = __gnu_debug::_Safe_iterator<__gnu_cxx::__normal_iterator<unsigned char*, std::__cxx1998::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > >, std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > > (mutable iterator);
      state = past-the-end;
      references sequence with type 'std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > >' @ 0x0x7fffffffcc50
    }

/usr/include/c++/7/debug/vector:417:
Error: attempt to subscript container with out-of-bounds index 556, but
container only holds 556 elements.
Objects involved in the operation:
    sequence "this" @ 0x0x2e87af8 {
      type = std::__debug::vector<partial_symbol*, std::allocator<partial_symbol*> >;
    }

The two -D_GLIBCXX_DEBUG regressions were made by:

commit bc8f2430e08cc2a520db49a42686e0529be4a3bc
Author: Jan Kratochvil <jan.kratochvil@redhat.com>
Date:   Mon Jun 12 16:29:53 2017 +0100
    Code cleanup: C++ify .gdb_index producer

commit af5bf4ada48ff65b6658be1fab8f9c8f8ab5f319
Author: Simon Marchi <simon.marchi@ericsson.com>
Date:   Sat Oct 14 08:06:29 2017 -0400
    Replace psymbol_allocation_list with std::vector

gdb/ChangeLog
2018-04-12  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR gdb/23053
	* dwarf-index-write.c (data_buf::grow) (write_one_signatured_type)
	(recursively_write_psymbols) (debug_names::recursively_write_psymbols)
	(debug_names::write_one_signatured_type): Fix -D_GLIBCXX_DEBUG
	regression.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 836ac9e100cd261c961edccd32674d649515e325..1141a1d8bb1982d78f331f9b847db6fed17308ec 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2018-04-12  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+       PR gdb/23053
+       * dwarf-index-write.c (data_buf::grow) (write_one_signatured_type)
+       (recursively_write_psymbols) (debug_names::recursively_write_psymbols)
+       (debug_names::write_one_signatured_type): Fix -D_GLIBCXX_DEBUG
+       regression.
+
 2018-04-12  Tom Tromey  <tom@tromey.com>
 
        * rust-lang.c (rust_print_struct_def): Remove univariant code.

diff --git a/gdb/dwarf-index-write.c b/gdb/dwarf-index-write.c
index 4c596c2e3eb083e30ed3f03b5757d0ce445e3eef..a5e196db32fc40aea7cc6768997a183ded703989 100644 (file)
--- a/gdb/dwarf-index-write.c
+++ b/gdb/dwarf-index-write.c
@@ -154,7 +154,7 @@ private:
   gdb_byte *grow (size_t size)
   {
     m_vec.resize (m_vec.size () + size);
-    return &*m_vec.end () - size;
+    return &*(m_vec.end () - size);
   }
 
   gdb::byte_vector m_vec;
@@ -588,12 +588,14 @@ write_one_signatured_type (void **slot, void *d)
 
   write_psymbols (info->symtab,
                  info->psyms_seen,
-                 &info->objfile->global_psymbols[psymtab->globals_offset],
+                 (info->objfile->global_psymbols.data ()
+                  + psymtab->globals_offset),
                  psymtab->n_global_syms, info->cu_index,
                  0);
   write_psymbols (info->symtab,
                  info->psyms_seen,
-                 &info->objfile->static_psymbols[psymtab->statics_offset],
+                 (info->objfile->static_psymbols.data ()
+                  + psymtab->statics_offset),
                  psymtab->n_static_syms, info->cu_index,
                  1);
 
@@ -643,12 +645,12 @@ recursively_write_psymbols (struct objfile *objfile,
 
   write_psymbols (symtab,
                  psyms_seen,
-                 &objfile->global_psymbols[psymtab->globals_offset],
+                 objfile->global_psymbols.data () + psymtab->globals_offset,
                  psymtab->n_global_syms, cu_index,
                  0);
   write_psymbols (symtab,
                  psyms_seen,
-                 &objfile->static_psymbols[psymtab->statics_offset],
+                 objfile->static_psymbols.data () + psymtab->statics_offset,
                  psymtab->n_static_syms, cu_index,
                  1);
 }
@@ -839,10 +841,10 @@ public:
                                    psyms_seen, cu_index);
 
     write_psymbols (psyms_seen,
-                   &objfile->global_psymbols[psymtab->globals_offset],
+                   objfile->global_psymbols.data () + psymtab->globals_offset,
                    psymtab->n_global_syms, cu_index, false, unit_kind::cu);
     write_psymbols (psyms_seen,
-                   &objfile->static_psymbols[psymtab->statics_offset],
+                   objfile->static_psymbols.data () + psymtab->statics_offset,
                    psymtab->n_static_syms, cu_index, true, unit_kind::cu);
   }
 
@@ -1200,11 +1202,13 @@ private:
     struct partial_symtab *psymtab = entry->per_cu.v.psymtab;
 
     write_psymbols (info->psyms_seen,
-                   &info->objfile->global_psymbols[psymtab->globals_offset],
+                   (info->objfile->global_psymbols.data ()
+                    + psymtab->globals_offset),
                    psymtab->n_global_syms, info->cu_index, false,
                    unit_kind::tu);
     write_psymbols (info->psyms_seen,
-                   &info->objfile->static_psymbols[psymtab->statics_offset],
+                   (info->objfile->static_psymbols.data ()
+                    + psymtab->statics_offset),
                    psymtab->n_static_syms, info->cu_index, true,
                    unit_kind::tu);