[PATCH v2] Make '{add-,}symbol-file' not care about the position of command line arguments

[Sergio Durigan Junior <sergiodj at redhat dot com>]

Changes from v1:

- Commit message has been rewritten.

- Implemented position-independent argument parsing for
  'add-symbol-file'.

- Added testcases.


This is a bug that's been detected while doing the readnever work.

If you use 'symbol-file' or 'add-symbol-file', the position of each
argument passed to the command matters.  This means that if you do:

  (gdb) symbol-file -readnow /foo/bar

The symbol file specified will (correctly) have all of its symbols
read by GDB (because of the -readnow flag).  However, if you do:

  (gdb) symbol-file /foo/bar -readnow

GDB will silently ignore the -readnow flag, because it was specified
after the filename.  This is not a good thing to do and may confuse
the user.

To address that, I've modified the argument parsing mechanisms of
symbol_file_command and add_symbol_file_command to be
"position-independent".  I have also added one error call at the end
of add_symbol_file_command's argument parsing logic, which now clearly
complains if no filename has been specified.

This patch provides a testcase for both commands, in order to make
sure that the argument order does not matter.  It has been
regression-tested on BuildBot.

gdb/ChangeLog:

2017-11-29  Sergio Durigan Junior  <sergiodj@redhat.com>

	* symfile.c (symbol_file_command): Call
	'symbol_file_add_main_1' only after processing all command
	line options.
	(add_symbol_file_command): Modify logic to make arguments
	position-independent.

gdb/testsuite/ChangeLog:

2017-11-29  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/relocate.exp: Add tests to guarantee that arguments
	to 'symbol-file' and 'add-symbol-file' can be
	position-independent.
---
 gdb/symfile.c                       | 61 +++++++++++++++++++------------------
 gdb/testsuite/gdb.base/relocate.exp | 38 +++++++++++++++++++++++
 2 files changed, 70 insertions(+), 29 deletions(-)

diff --git a/gdb/symfile.c b/gdb/symfile.c
index 4bbe0b5a62..1d6989c1b9 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -1634,14 +1634,13 @@ symbol_file_command (const char *args, int from_tty)
 	  else if (*arg == '-')
 	    error (_("unknown option `%s'"), arg);
 	  else
-	    {
-	      symbol_file_add_main_1 (arg, add_flags, flags);
-	      name = arg;
-	    }
+	    name = arg;
 	}
 
       if (name == NULL)
 	error (_("no symbol file name was specified"));
+
+      symbol_file_add_main_1 (name, add_flags, flags);
     }
 }
 
@@ -2180,8 +2179,9 @@ add_symbol_file_command (const char *args, int from_tty)
   char *arg;
   int argcnt = 0;
   int sec_num = 0;
-  int expecting_sec_name = 0;
-  int expecting_sec_addr = 0;
+  bool expecting_sec_name = false;
+  bool expecting_sec_addr = false;
+  bool seen_addr = false;
   struct objfile *objf;
   objfile_flags flags = OBJF_USERLOADED | OBJF_SHARED;
   symfile_add_flags add_flags = 0;
@@ -2208,46 +2208,49 @@ add_symbol_file_command (const char *args, int from_tty)
 
   for (arg = argv[0], argcnt = 0; arg != NULL; arg = argv[++argcnt])
     {
-      /* Process the argument.  */
-      if (argcnt == 0)
-	{
-	  /* The first argument is the file name.  */
-	  filename.reset (tilde_expand (arg));
-	}
-      else if (argcnt == 1)
-	{
-	  /* The second argument is always the text address at which
-	     to load the program.  */
-	  sect_opt sect = { ".text", arg };
-	  sect_opts.push_back (sect);
-	}
-      else
+      if (*arg != '-')
 	{
-	  /* It's an option (starting with '-') or it's an argument
-	     to an option.  */
 	  if (expecting_sec_name)
 	    {
 	      sect_opt sect = { arg, NULL };
 	      sect_opts.push_back (sect);
-	      expecting_sec_name = 0;
+	      expecting_sec_name = false;
 	    }
 	  else if (expecting_sec_addr)
 	    {
 	      sect_opts.back ().value = arg;
-	      expecting_sec_addr = 0;
+	      expecting_sec_addr = false;
 	    }
-	  else if (strcmp (arg, "-readnow") == 0)
-	    flags |= OBJF_READNOW;
-	  else if (strcmp (arg, "-s") == 0)
+	  else if (filename == NULL)
+	    {
+	      /* First non-option argument is always the filename.  */
+	      filename.reset (tilde_expand (arg));
+	    }
+	  else if (!seen_addr)
 	    {
-	      expecting_sec_name = 1;
-	      expecting_sec_addr = 1;
+	      /* The second non-option argument is always the text
+		 address at which to load the program.  */
+	      sect_opt sect = { ".text", arg };
+	      sect_opts.push_back (sect);
+	      seen_addr = true;
 	    }
 	  else
 	    error (_("Unrecognized argument \"%s\""), arg);
 	}
+      else if (strcmp (arg, "-readnow") == 0)
+	flags |= OBJF_READNOW;
+      else if (strcmp (arg, "-s") == 0)
+	{
+	  expecting_sec_name = true;
+	  expecting_sec_addr = true;
+	}
+      else
+	error (_("Unrecognized argument \"%s\""), arg);
     }
 
+  if (filename == NULL)
+    error (_("You must provide a filename to be loaded."));
+
   /* This command takes at least two arguments.  The first one is a
      filename, and the second is the address where this file has been
      loaded.  Abort now if this address hasn't been provided by the
diff --git a/gdb/testsuite/gdb.base/relocate.exp b/gdb/testsuite/gdb.base/relocate.exp
index 6eef15fb20..6a5ec5e201 100644
--- a/gdb/testsuite/gdb.base/relocate.exp
+++ b/gdb/testsuite/gdb.base/relocate.exp
@@ -37,6 +37,44 @@ foreach x {"-raednow" "readnow" "foo" "-readnow s"} {
 	"add-symbol-file: unknown option $word"
 }
 
+# Check that we can pass parameters using any position in the command
+# line.
+gdb_test "add-symbol-file -readnow $binfile 0x0 -s .bss 0x3" \
+    "Not confirmed\." \
+    "add-symbol-file positionless -readnow" \
+    "add symbol table from file \"${binfile}\" at\r\n\t\.text_addr = 0x0\r\n\t\.bss_addr = 0x3\r\n\\(y or n\\) " \
+    "n"
+# When we use -s as the first argument, the section will be printed
+# first as well.
+gdb_test "add-symbol-file -s .bss 0x3 -readnow $binfile 0x0" \
+    "Not confirmed\." \
+    "add-symbol-file positionless -s" \
+    "add symbol table from file \"${binfile}\" at\r\n\t\.bss_addr = 0x3\r\n\t\.text_addr = 0x0\r\n\\(y or n\\) " \
+    "n"
+gdb_test "add-symbol-file $binfile 0x0 -s .bss 0x3" \
+    "Not confirmed\." \
+    "add-symbol-file positionless -s, no -readnow" \
+    "add symbol table from file \"${binfile}\" at\r\n\t\.text_addr = 0x0\r\n\t\.bss_addr = 0x3\r\n\\(y or n\\) " \
+    "n"
+# Since we're here, might as well test the 'symbol-file' command and
+# if its arguments can also be passed at any position.
+gdb_test "symbol-file -readnow $binfile" \
+    "Reading symbols from ${binfile}\.\.\.expanding to full symbols\.\.\.done\." \
+    "symbol-file with -readnow first"
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_test "symbol-file $binfile -readnow" \
+    "Reading symbols from ${binfile}\.\.\.expanding to full symbols\.\.\.done\." \
+    "symbol-file with -readnow second"
+gdb_test "symbol-file -readnow" \
+    "no symbol file name was specified" \
+    "symbol-file without filename"
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+
 gdb_test "add-symbol-file ${binfile} 0 -s" \
     "Missing section name after .-s." \
     "add-symbol-file bare -s"
-- 
2.13.3