[PATCH v2 01/22] Remove cleanups from coffread.c

[Tom Tromey <tom at tromey dot com>]

This removes the remaining cleanups from coffread.c.

Tested by the buildbot.  However, I don't think the buildbot really
tests these code paths, and TBH I am not sure how to do it manually.
I did manage to crash an earlier version of the patch using a mingw
.exe file, though I would have thought that was only going to test
coff-pe-read.c.

This version includes the fix provided by Joel.

gdb/ChangeLog
2019-02-27  Joel Brobecker  <brobecker@adacore.com>
	    Tom Tromey  <tom@tromey.com>

	* stabsread.h (struct stab_section_list): Remove.
	(coffstab_build_psymtabs): Update.
	* dbxread.c (symbuf_sections): Now a std::vector.
	(sect_idx): New global.
	(fill_symbuf): Update.
	(coffstab_build_psymtabs): Change type of stabsects parameter.
	Update.
	* coffread.c (struct coff_symfile_info) <stabsects>: Now a
	std::vector.
	(linetab, linetab_offset, linetab_size, stringtab): Move earlier.
	(coff_locate_sections): Update.
	(coff_symfile_read): Remove cleanups.  Update.
	(init_stringtab): Add storage parameter.
	(free_stringtab, free_stringtab_cleanup): Remove.
	(init_lineno): Add storage parameter.
	(free_linetab, free_linetab_cleanup): Remove.
---
 gdb/ChangeLog   |  20 +++++++++
 gdb/coffread.c  | 115 ++++++++++++++----------------------------------
 gdb/dbxread.c   |  32 +++++++-------
 gdb/stabsread.h |  14 +-----
 4 files changed, 72 insertions(+), 109 deletions(-)

diff --git a/gdb/coffread.c b/gdb/coffread.c
index 6381cd3f370..4fbeece5fb7 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -58,7 +58,7 @@ struct coff_symfile_info
 
     CORE_ADDR textaddr;		/* Addr of .text section.  */
     unsigned int textsize;	/* Size of .text section.  */
-    struct stab_section_list *stabsects;	/* .stab sections.  */
+    std::vector<asection *> *stabsects;	/* .stab sections.  */
     asection *stabstrsect;	/* Section pointer for .stab section.  */
     char *stabstrdata;
   };
@@ -155,6 +155,12 @@ static int type_vector_length;
 
 #define INITIAL_TYPE_VECTOR_LENGTH 160
 
+static char *linetab = NULL;
+static long linetab_offset;
+static unsigned long linetab_size;
+
+static char *stringtab = NULL;
+
 extern void stabsread_clear_cache (void);
 
 static struct type *coff_read_struct_type (int, int, int,
@@ -185,21 +191,13 @@ static void patch_opaque_types (struct symtab *);
 
 static void enter_linenos (long, int, int, struct objfile *);
 
-static void free_linetab (void);
-
-static void free_linetab_cleanup (void *ignore);
-
-static int init_lineno (bfd *, long, int);
+static int init_lineno (bfd *, long, int, gdb::unique_xmalloc_ptr<char> *);
 
 static char *getsymname (struct internal_syment *);
 
 static const char *coff_getfilename (union internal_auxent *);
 
-static void free_stringtab (void);
-
-static void free_stringtab_cleanup (void *ignore);
-
-static int init_stringtab (bfd *, long);
+static int init_stringtab (bfd *, long, gdb::unique_xmalloc_ptr<char> *);
 
 static void read_one_sym (struct coff_symbol *,
 			  struct internal_syment *,
@@ -249,21 +247,7 @@ coff_locate_sections (bfd *abfd, asection *sectp, void *csip)
 	if (!isdigit (*s))
 	  break;
       if (*s == '\0')
-	{
-	  struct stab_section_list *n, **pn;
-
-	  n = XNEW (struct stab_section_list);
-	  n->section = sectp;
-	  n->next = NULL;
-	  for (pn = &csi->stabsects; *pn != NULL; pn = &(*pn)->next)
-	    ;
-	  *pn = n;
-
-	  /* This will be run after coffstab_build_psymtabs is called
-	     in coff_symfile_read, at which point we no longer need
-	     the information.  */
-	  make_cleanup (xfree, n);
-	}
+	csi->stabsects->push_back (sectp);
     }
 }
 
@@ -570,13 +554,16 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
   unsigned int num_symbols;
   int symtab_offset;
   int stringtab_offset;
-  struct cleanup *back_to;
   int stabstrsize;
   
   info = (struct coff_symfile_info *) objfile_data (objfile,
 						    coff_objfile_data_key);
   symfile_bfd = abfd;		/* Kludge for swap routines.  */
 
+  std::vector<asection *> stabsects;
+  scoped_restore restore_stabsects
+    = make_scoped_restore (&info->stabsects, &stabsects);
+
 /* WARNING WILL ROBINSON!  ACCESSING BFD-PRIVATE DATA HERE!  FIXME!  */
   num_symbols = bfd_get_symcount (abfd);	/* How many syms */
   symtab_offset = cdata->sym_filepos;	/* Symbol table file offset */
@@ -595,10 +582,10 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 
   /* Allocate space for raw symbol and aux entries, based on their
      space requirements as reported by BFD.  */
-  temp_sym = (char *) xmalloc
-    (cdata->local_symesz + cdata->local_auxesz);
+  gdb::def_vector<char> temp_storage (cdata->local_symesz
+				      + cdata->local_auxesz);
+  temp_sym = temp_storage.data ();
   temp_aux = temp_sym + cdata->local_symesz;
-  back_to = make_cleanup (free_current_contents, &temp_sym);
 
   /* We need to know whether this is a PE file, because in PE files,
      unlike standard COFF files, symbol values are stored as offsets
@@ -628,22 +615,25 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
      can avoid spurious error messages (and maybe run a little
      faster!) by not even reading the line number table unless we have
      symbols.  */
+  scoped_restore restore_linetab = make_scoped_restore (&linetab);
+  gdb::unique_xmalloc_ptr<char> linetab_storage;
   if (num_symbols > 0)
     {
       /* Read the line number table, all at once.  */
       bfd_map_over_sections (abfd, find_linenos, (void *) info);
 
-      make_cleanup (free_linetab_cleanup, 0 /*ignore*/);
       val = init_lineno (abfd, info->min_lineno_offset,
-                         info->max_lineno_offset - info->min_lineno_offset);
+                         info->max_lineno_offset - info->min_lineno_offset,
+			 &linetab_storage);
       if (val < 0)
         error (_("\"%s\": error reading line numbers."), filename);
     }
 
   /* Now read the string table, all at once.  */
 
-  make_cleanup (free_stringtab_cleanup, 0 /*ignore*/);
-  val = init_stringtab (abfd, stringtab_offset);
+  scoped_restore restore_stringtab = make_scoped_restore (&stringtab);
+  gdb::unique_xmalloc_ptr<char> stringtab_storage;
+  val = init_stringtab (abfd, stringtab_offset, &stringtab_storage);
   if (val < 0)
     error (_("\"%s\": can't get string table"), filename);
 
@@ -701,7 +691,7 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
   if (!(objfile->flags & OBJF_READNEVER))
     bfd_map_over_sections (abfd, coff_locate_sections, (void *) info);
 
-  if (info->stabsects)
+  if (! info->stabsects->empty())
     {
       if (!info->stabstrsect)
 	{
@@ -718,7 +708,7 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 
       coffstab_build_psymtabs (objfile,
 			       info->textaddr, info->textsize,
-			       info->stabsects,
+			       *info->stabsects,
 			       info->stabstrsect->filepos, stabstrsize);
     }
   if (dwarf2_has_info (objfile, NULL))
@@ -745,8 +735,6 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
 				    symfile_flags, objfile);
 	}
     }
-
-  do_cleanups (back_to);
 }
 
 static void
@@ -1298,17 +1286,13 @@ read_one_sym (struct coff_symbol *cs,
 
 /* Support for string table handling.  */
 
-static char *stringtab = NULL;
-
 static int
-init_stringtab (bfd *abfd, long offset)
+init_stringtab (bfd *abfd, long offset, gdb::unique_xmalloc_ptr<char> *storage)
 {
   long length;
   int val;
   unsigned char lengthbuf[4];
 
-  free_stringtab ();
-
   /* If the file is stripped, the offset might be zero, indicating no
      string table.  Just return with `stringtab' set to null.  */
   if (offset == 0)
@@ -1325,7 +1309,8 @@ init_stringtab (bfd *abfd, long offset)
   if (val != sizeof lengthbuf || length < sizeof lengthbuf)
     return 0;
 
-  stringtab = (char *) xmalloc (length);
+  storage->reset ((char *) xmalloc (length));
+  stringtab = storage->get ();
   /* This is in target format (probably not very useful, and not
      currently used), not host format.  */
   memcpy (stringtab, lengthbuf, sizeof lengthbuf);
@@ -1340,20 +1325,6 @@ init_stringtab (bfd *abfd, long offset)
   return 0;
 }
 
-static void
-free_stringtab (void)
-{
-  if (stringtab)
-    xfree (stringtab);
-  stringtab = NULL;
-}
-
-static void
-free_stringtab_cleanup (void *ignore)
-{
-  free_stringtab ();
-}
-
 static char *
 getsymname (struct internal_syment *symbol_entry)
 {
@@ -1407,24 +1378,19 @@ coff_getfilename (union internal_auxent *aux_entry)
 
 /* Support for line number handling.  */
 
-static char *linetab = NULL;
-static long linetab_offset;
-static unsigned long linetab_size;
-
 /* Read in all the line numbers for fast lookups later.  Leave them in
    external (unswapped) format in memory; we'll swap them as we enter
    them into GDB's data structures.  */
 
 static int
-init_lineno (bfd *abfd, long offset, int size)
+init_lineno (bfd *abfd, long offset, int size,
+	     gdb::unique_xmalloc_ptr<char> *storage)
 {
   int val;
 
   linetab_offset = offset;
   linetab_size = size;
 
-  free_linetab ();
-
   if (size == 0)
     return 0;
 
@@ -1432,9 +1398,10 @@ init_lineno (bfd *abfd, long offset, int size)
     return -1;
 
   /* Allocate the desired table, plus a sentinel.  */
-  linetab = (char *) xmalloc (size + local_linesz);
+  storage->reset ((char *) xmalloc (size + local_linesz));
+  linetab = storage->get ();
 
-  val = bfd_bread (linetab, size, abfd);
+  val = bfd_bread (storage->get (), size, abfd);
   if (val != size)
     return -1;
 
@@ -1444,20 +1411,6 @@ init_lineno (bfd *abfd, long offset, int size)
   return 0;
 }
 
-static void
-free_linetab (void)
-{
-  if (linetab)
-    xfree (linetab);
-  linetab = NULL;
-}
-
-static void
-free_linetab_cleanup (void *ignore)
-{
-  free_linetab ();
-}
-
 #if !defined (L_LNNO32)
 #define L_LNNO32(lp) ((lp)->l_lnno)
 #endif
diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index 60d384b27fe..ad2edc3ff4b 100644
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -747,7 +747,8 @@ static char *stringtab_global;
 /* These variables are used to control fill_symbuf when the stabs
    symbols are not contiguous (as may be the case when a COFF file is
    linked using --split-by-reloc).  */
-static struct stab_section_list *symbuf_sections;
+static const std::vector<asection *> *symbuf_sections;
+static size_t sect_idx;
 static unsigned int symbuf_left;
 static unsigned int symbuf_read;
 
@@ -783,13 +784,13 @@ fill_symbuf (bfd *sym_bfd)
     {
       if (symbuf_left <= 0)
 	{
-	  file_ptr filepos = symbuf_sections->section->filepos;
+	  file_ptr filepos = (*symbuf_sections)[sect_idx]->filepos;
 
 	  if (bfd_seek (sym_bfd, filepos, SEEK_SET) != 0)
 	    perror_with_name (bfd_get_filename (sym_bfd));
-	  symbuf_left = bfd_section_size (sym_bfd, symbuf_sections->section);
+	  symbuf_left = bfd_section_size (sym_bfd, (*symbuf_sections)[sect_idx]);
 	  symbol_table_offset = filepos - symbuf_read;
-	  symbuf_sections = symbuf_sections->next;
+	  ++sect_idx;
 	}
 
       count = symbuf_left;
@@ -2942,7 +2943,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, const char *name,
 void
 coffstab_build_psymtabs (struct objfile *objfile,
 			 CORE_ADDR textaddr, unsigned int textsize,
-			 struct stab_section_list *stabsects,
+			 const std::vector<asection *> &stabsects,
 			 file_ptr stabstroffset, unsigned int stabstrsize)
 {
   int val;
@@ -2981,27 +2982,28 @@ coffstab_build_psymtabs (struct objfile *objfile,
   /* In a coff file, we've already installed the minimal symbols that came
      from the coff (non-stab) symbol table, so always act like an
      incremental load here.  */
-  if (stabsects->next == NULL)
+  scoped_restore save_symbuf_sections
+    = make_scoped_restore (&symbuf_sections);
+  if (stabsects.size () == 1)
     {
-      stabsize = bfd_section_size (sym_bfd, stabsects->section);
+      stabsize = bfd_section_size (sym_bfd, stabsects[0]);
       DBX_SYMCOUNT (objfile) = stabsize / DBX_SYMBOL_SIZE (objfile);
-      DBX_SYMTAB_OFFSET (objfile) = stabsects->section->filepos;
+      DBX_SYMTAB_OFFSET (objfile) = stabsects[0]->filepos;
     }
   else
     {
-      struct stab_section_list *stabsect;
-
       DBX_SYMCOUNT (objfile) = 0;
-      for (stabsect = stabsects; stabsect != NULL; stabsect = stabsect->next)
+      for (asection *section : stabsects)
 	{
-	  stabsize = bfd_section_size (sym_bfd, stabsect->section);
+	  stabsize = bfd_section_size (sym_bfd, section);
 	  DBX_SYMCOUNT (objfile) += stabsize / DBX_SYMBOL_SIZE (objfile);
 	}
 
-      DBX_SYMTAB_OFFSET (objfile) = stabsects->section->filepos;
+      DBX_SYMTAB_OFFSET (objfile) = stabsects[0]->filepos;
 
-      symbuf_sections = stabsects->next;
-      symbuf_left = bfd_section_size (sym_bfd, stabsects->section);
+      sect_idx = 1;
+      symbuf_sections = &stabsects;
+      symbuf_left = bfd_section_size (sym_bfd, stabsects[0]);
       symbuf_read = 0;
     }
 
diff --git a/gdb/stabsread.h b/gdb/stabsread.h
index fc989bc8994..f6928083d7c 100644
--- a/gdb/stabsread.h
+++ b/gdb/stabsread.h
@@ -167,18 +167,6 @@ extern void end_stabs (void);
 
 extern void finish_global_stabs (struct objfile *objfile);
 
-/* COFF files can have multiple .stab sections, if they are linked
-   using --split-by-reloc.  This linked list is used to pass the
-   information into the functions in dbxread.c.  */
-struct stab_section_list
-  {
-    /* Next in list.  */
-    struct stab_section_list *next;
-
-    /* Stab section.  */
-    asection *section;
-  };
-
 /* Functions exported by dbxread.c.  These are not in stabsread.c because
    they are only used by some stabs readers.  */
 
@@ -201,7 +189,7 @@ extern void elfstab_build_psymtabs (struct objfile *objfile,
 extern void coffstab_build_psymtabs
   (struct objfile *objfile,
    CORE_ADDR textaddr, unsigned int textsize,
-   struct stab_section_list *stabs,
+   const std::vector<asection *> &stabs,
    file_ptr stabstroffset, unsigned int stabstrsize);
 
 extern void stabsect_build_psymtabs (struct objfile *objfile, char *stab_name,
-- 
2.17.2