From 042d75e42c5572f333e0e06dabd3c5c4afab486c Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sat, 2 Mar 2019 12:29:48 -0700 Subject: [PATCH] Allocate minimal symbols with malloc Currently, minimal symbols are allocated on the per-BFD obstack. However, it is also possible for multiple symbol readers to create minimal symbols for a given objfile. In this case, the minimal symbols will be reallocated on the obstack, leading to some waste of storage. This is a memory leak, but I think it won't be caught by tools like valgrind, because valgrind doesn't know about obstacks. This patch fixes the problem by using malloc to allocate the storage for minimal symbols. gdb/ChangeLog 2019-03-15 Tom Tromey * objfiles.h (struct objfile_per_bfd_storage) : Now a unique_xmalloc_ptr. (objfile::msymbols_range::begin, objfile::msymbols_range::end): Update. * minsyms.c (lookup_minimal_symbol_by_pc_section) (build_minimal_symbol_hash_tables) (minimal_symbol_reader::install): Update. --- gdb/ChangeLog | 10 ++++++++++ gdb/minsyms.c | 25 ++++++++++++------------- gdb/objfiles.h | 10 ++++------ 3 files changed, 26 insertions(+), 19 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3a9532047a0..581a4c6a5a9 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2019-03-15 Tom Tromey + + * objfiles.h (struct objfile_per_bfd_storage) : Now a + unique_xmalloc_ptr. + (objfile::msymbols_range::begin, objfile::msymbols_range::end): + Update. + * minsyms.c (lookup_minimal_symbol_by_pc_section) + (build_minimal_symbol_hash_tables) + (minimal_symbol_reader::install): Update. + 2019-03-15 Tom Tromey * symtab.c (create_demangled_names_hash): Update. diff --git a/gdb/minsyms.c b/gdb/minsyms.c index efeaf2a0194..88ff2593493 100644 --- a/gdb/minsyms.c +++ b/gdb/minsyms.c @@ -742,7 +742,7 @@ lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *sectio { int best_zero_sized = -1; - msymbol = objfile->per_bfd->msymbols; + msymbol = objfile->per_bfd->msymbols.get (); lo = 0; hi = objfile->per_bfd->minimal_symbol_count - 1; @@ -1298,7 +1298,7 @@ build_minimal_symbol_hash_tables (struct objfile *objfile) /* Now, (re)insert the actual entries. */ for ((i = objfile->per_bfd->minimal_symbol_count, - msym = objfile->per_bfd->msymbols); + msym = objfile->per_bfd->msymbols.get ()); i > 0; i--, msym++) { @@ -1363,14 +1363,16 @@ minimal_symbol_reader::install () alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count; obstack_blank (&m_objfile->per_bfd->storage_obstack, alloc_count * sizeof (struct minimal_symbol)); - msymbols = (struct minimal_symbol *) - obstack_base (&m_objfile->per_bfd->storage_obstack); + gdb::unique_xmalloc_ptr + msym_holder (XNEWVEC (minimal_symbol, alloc_count)); + msymbols = msym_holder.get (); /* Copy in the existing minimal symbols, if there are any. */ if (m_objfile->per_bfd->minimal_symbol_count) - memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols, - m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol)); + memcpy (msymbols, m_objfile->per_bfd->msymbols.get (), + m_objfile->per_bfd->minimal_symbol_count + * sizeof (struct minimal_symbol)); /* Walk through the list of minimal symbol bunches, adding each symbol to the new contiguous array of symbols. Note that we start with the @@ -1396,19 +1398,16 @@ minimal_symbol_reader::install () no longer using. */ mcount = compact_minimal_symbols (msymbols, mcount, m_objfile); - - ssize_t shrink_bytes - = (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol); - obstack_blank_fast (&m_objfile->per_bfd->storage_obstack, shrink_bytes); - msymbols = (struct minimal_symbol *) - obstack_finish (&m_objfile->per_bfd->storage_obstack); + msym_holder.reset (XRESIZEVEC (struct minimal_symbol, + msym_holder.release (), + mcount)); /* Attach the minimal symbol table to the specified objfile. The strings themselves are also located in the storage_obstack of this objfile. */ m_objfile->per_bfd->minimal_symbol_count = mcount; - m_objfile->per_bfd->msymbols = msymbols; + m_objfile->per_bfd->msymbols = std::move (msym_holder); /* Now build the hash tables; we can't do this incrementally at an earlier point since we weren't finished with the obstack diff --git a/gdb/objfiles.h b/gdb/objfiles.h index 1fa6f3c40ab..b07ddfdfa50 100644 --- a/gdb/objfiles.h +++ b/gdb/objfiles.h @@ -282,11 +282,9 @@ struct objfile_per_bfd_storage name and a zero value for the address. This makes it easy to walk through the array when passed a pointer to somewhere in the middle of it. There is also a count of the number of symbols, which does - not include the terminating null symbol. The array itself, as well - as all the data that it points to, should be allocated on the - objfile_obstack for this file. */ + not include the terminating null symbol. */ - minimal_symbol *msymbols = NULL; + gdb::unique_xmalloc_ptr msymbols; int minimal_symbol_count = 0; /* The number of minimal symbols read, before any minimal symbol @@ -375,13 +373,13 @@ struct objfile minimal_symbol_iterator begin () const { - return minimal_symbol_iterator (m_objfile->per_bfd->msymbols); + return minimal_symbol_iterator (m_objfile->per_bfd->msymbols.get ()); } minimal_symbol_iterator end () const { return minimal_symbol_iterator - (m_objfile->per_bfd->msymbols + (m_objfile->per_bfd->msymbols.get () + m_objfile->per_bfd->minimal_symbol_count); } -- 2.30.2