[PATCH] Delay allocation of dbx_symfile_info

[Tom Tromey <tromey@adacore.com>]

I noticed that elfread.c always allocates a dbx_symfile_info, even
though this is only ever needed in the unusual case of reading stabs
in ELF.

This patch moves the allocation into dbxread.c, and applies the same
treatment to similar code in coffread.c.

Regression tested on x86-64 Fedora 29.

gdb/ChangeLog
2019-06-07  Tom Tromey  <tromey@adacore.com>

	* elfread.c (elf_read_minimal_symbols): Don't set the dbx objfile
	data.
	(elf_new_init): Don't call stabsread_new_init.
	* dbxread.c (coffstab_build_psymtabs): Set dbx objfile data.
	(elfstab_build_psymtabs): Likewise.  Call stabsread_new_init.
	* coffread.c (coff_symfile_init): Don't set the dbx objfile data.
---
 gdb/ChangeLog  |  9 +++++++++
 gdb/coffread.c |  7 -------
 gdb/dbxread.c  | 10 ++++++++++
 gdb/elfread.c  | 12 +-----------
 4 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/gdb/coffread.c b/gdb/coffread.c
index 0956f3897b4..6e379dd1e52 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -31,7 +31,6 @@
 #include "libcoff.h"		/* FIXME secret internal data from BFD */
 #include "objfiles.h"
 #include "buildsym-legacy.h"
-#include "gdb-stabs.h"
 #include "stabsread.h"
 #include "complaints.h"
 #include "target.h"
@@ -484,12 +483,6 @@ record_minimal_symbol (minimal_symbol_reader &reader,
 static void
 coff_symfile_init (struct objfile *objfile)
 {
-  struct dbx_symfile_info *dbx;
-
-  /* Allocate struct to keep track of stab reading.  */
-  dbx = XCNEW (struct dbx_symfile_info);
-  set_objfile_data (objfile, dbx_objfile_data_key, dbx);
-
   /* Allocate struct to keep track of the symfile.  */
   coff_objfile_data_key.emplace (objfile);
 
diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index ad2edc3ff4b..307debd2824 100644
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -2951,6 +2951,10 @@ coffstab_build_psymtabs (struct objfile *objfile,
   char *name = bfd_get_filename (sym_bfd);
   unsigned int stabsize;
 
+  /* Allocate struct to keep track of stab reading.  */
+  struct dbx_symfile_info *dbx = XCNEW (struct dbx_symfile_info);
+  set_objfile_data (objfile, dbx_objfile_data_key, dbx);
+
   DBX_TEXT_ADDR (objfile) = textaddr;
   DBX_TEXT_SIZE (objfile) = textsize;
 
@@ -3034,6 +3038,12 @@ elfstab_build_psymtabs (struct objfile *objfile, asection *stabsect,
   bfd *sym_bfd = objfile->obfd;
   char *name = bfd_get_filename (sym_bfd);
 
+  stabsread_new_init ();
+
+  /* Allocate struct to keep track of stab reading.  */
+  struct dbx_symfile_info *dbx = XCNEW (struct dbx_symfile_info);
+  set_objfile_data (objfile, dbx_objfile_data_key, dbx);
+
   /* Find the first and last text address.  dbx_symfile_read seems to
      want this.  */
   find_text_range (sym_bfd, objfile);
diff --git a/gdb/elfread.c b/gdb/elfread.c
index cb98b83f74b..630550b80dc 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -29,7 +29,6 @@
 #include "symfile.h"
 #include "objfiles.h"
 #include "stabsread.h"
-#include "gdb-stabs.h"
 #include "complaints.h"
 #include "demangle.h"
 #include "psympriv.h"
@@ -1039,7 +1038,6 @@ elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags,
   long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
   asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
   asymbol *synthsyms;
-  struct dbx_symfile_info *dbx;
 
   if (symtab_create_debug)
     {
@@ -1065,10 +1063,6 @@ elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags,
 
   minimal_symbol_reader reader (objfile);
 
-  /* Allocate struct to keep track of the symfile.  */
-  dbx = XCNEW (struct dbx_symfile_info);
-  set_objfile_data (objfile, dbx_objfile_data_key, dbx);
-
   /* Process the normal ELF symbol table first.  */
 
   storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
@@ -1316,15 +1310,11 @@ read_psyms (struct objfile *objfile)
 
 /* Initialize anything that needs initializing when a completely new symbol
    file is specified (not just adding some symbols from another file, e.g. a
-   shared library).
-
-   We reinitialize buildsym, since we may be reading stabs from an ELF
-   file.  */
+   shared library).  */
 
 static void
 elf_new_init (struct objfile *ignore)
 {
-  stabsread_new_init ();
 }
 
 /* Perform any local cleanups required when we are done with a particular
-- 
2.20.1