* ada-lang.c (ada_read_renaming_var_value): Pass const

	pointer to expression string to parse_exp_1.
	(create_excep_cond_exprs): Likewise.
	* ax-gdb.c (agent_eval_command_one): Likewise.
	(maint_agent_printf_command): Likewise.
	Constify much of the string handling/parsing.
	* breakpoint.c (set_breakpoint_condition): Pass const
	pointer to expression string to parse_exp_1.
	(update_watchpoint): Likewise.
	(parse_cmd_to_aexpr): Constify string handling.
	Pass const pointer to parse_exp_1.
	(init_breakpoint_sal): Pass const pointer to parse_exp_1.
	(find_condition_and_thread): Likewise.
	Make TOK const.
	(watch_command_1): Make "arg" const.
	Constify string handling.
	Copy the expression string instead of changing the input
	string.
	(update_breakpoint_location): Pass const pointer to
	parse_exp_1.
	* eval.c (parse_and_eval_address): Make "exp" const.
	(parse_to_comma_and_eval): Make "expp" const.
	(parse_and_eval): Make "exp" const.
	* expression.h (parse_expression): Make argument const.
	(parse_exp_1): Make first argument const.
	* findcmd.c (parse_find_args): Treat "args" as const.
	* linespec.c (parse_linespec): Pass const pointer to
	linespec_expression_to_pc.
	(linespec_expression_to_pc): Make "exp_ptr" const.
	* parse.c (parse_exp_1): Make "stringptr" const.
	Make a copy of the expression to pass to parse_exp_in_context until
	this whole interface can be constified.
	(parse_expression): Make "string" const.
	* printcmd.c (ui_printf): Treat "arg" as const.
	Handle const strings.
	* tracepoint.c (validate_actionline): Pass const pointer to
	all calls to parse_exp_1.
	(encode_actions_1): Likewise.
	* value.h (parse_to_comma_and_eval): Make argument const.
	(parse_and_eval_address): Likewise.
	(parse_and_eval): Likewise.
	* varobj.c (varobj_create): Pass const pointer to parse_exp_1.
	(varobj_set_value): Likewise.
	* cli/cli-cmds.c (disassemble_command): Treat "arg" as const and
	constify string handling.
	Pass const pointers to parse_and_eval_address and
	parse_to_comman_and_eval.
	* cli/cli-utils.c (skip_to_space): Rename to ...
	(skip_to_space_const): ... this. Handle const strings.
	* cli/cli-utils.h (skip_to_space): Turn into macro which invokes
	skip_to_space_const.
	(skip_to_space_const): Declare.
	* common/format.c (parse_format_string): Make "arg" const.
	Handle const strings.
	* common/format.h (parse_format_string): Make "arg" const.
	* gdbserver/ax.c (ax_printf): Make "format" const.
	* python/python.c (gdbpy_parse_and_eval): Do not make a copy
	of the expression string.

20 files changed, 207 insertions, 109 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3069add..092d6ef 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,64 @@
+2013-03-12  Keith Seitz  <keiths@redhat.com>
+
+	* ada-lang.c (ada_read_renaming_var_value): Pass const
+	pointer to expression string to parse_exp_1.
+	(create_excep_cond_exprs): Likewise.
+	* ax-gdb.c (agent_eval_command_one): Likewise.
+	(maint_agent_printf_command): Likewise.
+	Constify much of the string handling/parsing.
+	* breakpoint.c (set_breakpoint_condition): Pass const
+	pointer to expression string to parse_exp_1.
+	(update_watchpoint): Likewise.
+	(parse_cmd_to_aexpr): Constify string handling.
+	Pass const pointer to parse_exp_1.
+	(init_breakpoint_sal): Pass const pointer to parse_exp_1.
+	(find_condition_and_thread): Likewise.
+	Make TOK const.
+	(watch_command_1): Make "arg" const.
+	Constify string handling.
+	Copy the expression string instead of changing the input
+	string.
+	(update_breakpoint_location): Pass const pointer to
+	parse_exp_1.
+	* eval.c (parse_and_eval_address): Make "exp" const.
+	(parse_to_comma_and_eval): Make "expp" const.
+	(parse_and_eval): Make "exp" const.
+	* expression.h (parse_expression): Make argument const.
+	(parse_exp_1): Make first argument const.
+	* findcmd.c (parse_find_args): Treat "args" as const.
+	* linespec.c (parse_linespec): Pass const pointer to
+	linespec_expression_to_pc.
+	(linespec_expression_to_pc): Make "exp_ptr" const.
+	* parse.c (parse_exp_1): Make "stringptr" const.
+	Make a copy of the expression to pass to parse_exp_in_context until
+	this whole interface can be constified.
+	(parse_expression): Make "string" const.
+	* printcmd.c (ui_printf): Treat "arg" as const.
+	Handle const strings.
+	* tracepoint.c (validate_actionline): Pass const pointer to
+	all calls to parse_exp_1.
+	(encode_actions_1): Likewise.
+	* value.h (parse_to_comma_and_eval): Make argument const.
+	(parse_and_eval_address): Likewise.
+	(parse_and_eval): Likewise.
+	* varobj.c (varobj_create): Pass const pointer to parse_exp_1.
+	(varobj_set_value): Likewise.
+	* cli/cli-cmds.c (disassemble_command): Treat "arg" as const and
+	constify string handling.
+	Pass const pointers to parse_and_eval_address and
+	parse_to_comman_and_eval.
+	* cli/cli-utils.c (skip_to_space): Rename to ...
+	(skip_to_space_const): ... this. Handle const strings.
+	* cli/cli-utils.h (skip_to_space): Turn into macro which invokes
+	skip_to_space_const.
+	(skip_to_space_const): Declare.
+	* common/format.c (parse_format_string): Make "arg" const.
+	Handle const strings.
+	* common/format.h (parse_format_string): Make "arg" const.
+	* gdbserver/ax.c (ax_printf): Make "format" const.
+	* python/python.c (gdbpy_parse_and_eval): Do not make a copy
+	of the expression string.
+
 2013-03-12  Hui Zhu  <hui@codesourcery.com>
 
 	* dwarf2loc.c (dwarf2_compile_expr_to_ax): Update error message.
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 75f1c3d..63a85ee 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -4056,15 +4056,14 @@ static struct value *
 ada_read_renaming_var_value (struct symbol *renaming_sym,
 			     struct block *block)
 {
-  char *sym_name;
+  const char *sym_name;
   struct expression *expr;
   struct value *value;
   struct cleanup *old_chain = NULL;
 
-  sym_name = xstrdup (SYMBOL_LINKAGE_NAME (renaming_sym));
-  old_chain = make_cleanup (xfree, sym_name);
+  sym_name = SYMBOL_LINKAGE_NAME (renaming_sym);
   expr = parse_exp_1 (&sym_name, 0, block, 0);
-  make_cleanup (free_current_contents, &expr);
+  old_chain = make_cleanup (free_current_contents, &expr);
   value = evaluate_expression (expr);
 
   do_cleanups (old_chain);
@@ -11385,7 +11384,7 @@ create_excep_cond_exprs (struct ada_catchpoint *c)
       if (!bl->shlib_disabled)
 	{
 	  volatile struct gdb_exception e;
-	  char *s;
+	  const char *s;
 
 	  s = cond_string;
 	  TRY_CATCH (e, RETURN_MASK_ERROR)
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 066826e..74824d3 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2608,6 +2608,7 @@ agent_eval_command_one (char *exp, int eval, CORE_ADDR pc)
   struct cleanup *old_chain = 0;
   struct expression *expr;
   struct agent_expr *agent;
+  const char *arg;
 
   if (!eval)
     {
@@ -2616,14 +2617,15 @@ agent_eval_command_one (char *exp, int eval, CORE_ADDR pc)
         exp = decode_agent_options (exp);
     }
 
-  if (!eval && strcmp (exp, "$_ret") == 0)
+  arg = exp;
+  if (!eval && strcmp (arg, "$_ret") == 0)
     {
       agent = gen_trace_for_return_address (pc, get_current_arch ());
       old_chain = make_cleanup_free_agent_expr (agent);
     }
   else
     {
-      expr = parse_exp_1 (&exp, pc, block_for_pc (pc), 0);
+      expr = parse_exp_1 (&arg, pc, block_for_pc (pc), 0);
       old_chain = make_cleanup (free_current_contents, &expr);
       if (eval)
 	agent = gen_eval_for_expr (pc, expr);
@@ -2716,8 +2718,8 @@ maint_agent_printf_command (char *exp, int from_tty)
   struct expression *argvec[100];
   struct agent_expr *agent;
   struct frame_info *fi = get_current_frame ();	/* need current scope */
-  char *cmdrest;
-  char *format_start, *format_end;
+  const char *cmdrest;
+  const char *format_start, *format_end;
   struct format_piece *fpieces;
   int nargs;
 
@@ -2733,7 +2735,7 @@ maint_agent_printf_command (char *exp, int from_tty)
 
   cmdrest = exp;
 
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   if (*cmdrest++ != '"')
     error (_("Must start with a format string."));
@@ -2749,19 +2751,19 @@ maint_agent_printf_command (char *exp, int from_tty)
   if (*cmdrest++ != '"')
     error (_("Bad format string, non-terminated '\"'."));
   
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   if (*cmdrest != ',' && *cmdrest != 0)
     error (_("Invalid argument syntax"));
 
   if (*cmdrest == ',')
     cmdrest++;
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   nargs = 0;
   while (*cmdrest != '\0')
     {
-      char *cmd1;
+      const char *cmd1;
 
       cmd1 = cmdrest;
       expr = parse_exp_1 (&cmd1, 0, (struct block *) 0, 1);
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index d6f8bc5..e5ee4d0 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -950,7 +950,7 @@ set_breakpoint_condition (struct breakpoint *b, char *exp,
     }
   else
     {
-      char *arg = exp;
+      const char *arg = exp;
 
       /* I don't know if it matters whether this is the string the user
 	 typed in or the decompiled expression.  */
@@ -1759,7 +1759,7 @@ update_watchpoint (struct watchpoint *b, int reparse)
 
   if (within_current_scope && reparse)
     {
-      char *s;
+      const char *s;
 
       if (b->exp)
 	{
@@ -2186,8 +2186,8 @@ parse_cmd_to_aexpr (CORE_ADDR scope, char *cmd)
   struct agent_expr *aexpr = NULL;
   struct cleanup *old_chain = NULL;
   volatile struct gdb_exception ex;
-  char *cmdrest;
-  char *format_start, *format_end;
+  const char *cmdrest;
+  const char *format_start, *format_end;
   struct format_piece *fpieces;
   int nargs;
   struct gdbarch *gdbarch = get_current_arch ();
@@ -2199,7 +2199,7 @@ parse_cmd_to_aexpr (CORE_ADDR scope, char *cmd)
 
   if (*cmdrest == ',')
     ++cmdrest;
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   if (*cmdrest++ != '"')
     error (_("No format string following the location"));
@@ -2215,14 +2215,14 @@ parse_cmd_to_aexpr (CORE_ADDR scope, char *cmd)
   if (*cmdrest++ != '"')
     error (_("Bad format string, non-terminated '\"'."));
   
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   if (!(*cmdrest == ',' || *cmdrest == '\0'))
     error (_("Invalid argument syntax"));
 
   if (*cmdrest == ',')
     cmdrest++;
-  cmdrest = skip_spaces (cmdrest);
+  cmdrest = skip_spaces_const (cmdrest);
 
   /* For each argument, make an expression.  */
 
@@ -2232,7 +2232,7 @@ parse_cmd_to_aexpr (CORE_ADDR scope, char *cmd)
   nargs = 0;
   while (*cmdrest != '\0')
     {
-      char *cmd1;
+      const char *cmd1;
 
       cmd1 = cmdrest;
       expr = parse_exp_1 (&cmd1, scope, block_for_pc (scope), 1);
@@ -9103,7 +9103,8 @@ init_breakpoint_sal (struct breakpoint *b, struct gdbarch *gdbarch,
 
       if (b->cond_string)
 	{
-	  char *arg = b->cond_string;
+	  const char *arg = b->cond_string;
+
 	  loc->cond = parse_exp_1 (&arg, loc->address,
 				   block_for_pc (loc->address), 0);
 	  if (*arg)
@@ -9374,7 +9375,7 @@ invalid_thread_id_error (int id)
    If no thread is found, *THREAD is set to -1.  */
 
 static void
-find_condition_and_thread (char *tok, CORE_ADDR pc,
+find_condition_and_thread (const char *tok, CORE_ADDR pc,
 			   char **cond_string, int *thread, int *task,
 			   char **rest)
 {
@@ -9385,12 +9386,12 @@ find_condition_and_thread (char *tok, CORE_ADDR pc,
 
   while (tok && *tok)
     {
-      char *end_tok;
+      const char *end_tok;
       int toklen;
-      char *cond_start = NULL;
-      char *cond_end = NULL;
+      const char *cond_start = NULL;
+      const char *cond_end = NULL;
 
-      tok = skip_spaces (tok);
+      tok = skip_spaces_const (tok);
 
       if ((*tok == '"' || *tok == ',') && rest)
 	{
@@ -9398,7 +9399,7 @@ find_condition_and_thread (char *tok, CORE_ADDR pc,
 	  return;
 	}
 
-      end_tok = skip_to_space (tok);
+      end_tok = skip_to_space_const (tok);
 
       toklen = end_tok - tok;
 
@@ -9417,24 +9418,24 @@ find_condition_and_thread (char *tok, CORE_ADDR pc,
 	  char *tmptok;
 
 	  tok = end_tok + 1;
-	  tmptok = tok;
-	  *thread = strtol (tok, &tok, 0);
+	  *thread = strtol (tok, &tmptok, 0);
 	  if (tok == tmptok)
 	    error (_("Junk after thread keyword."));
 	  if (!valid_thread_id (*thread))
 	    invalid_thread_id_error (*thread);
+	  tok = tmptok;
 	}
       else if (toklen >= 1 && strncmp (tok, "task", toklen) == 0)
 	{
 	  char *tmptok;
 
 	  tok = end_tok + 1;
-	  tmptok = tok;
-	  *task = strtol (tok, &tok, 0);
+	  *task = strtol (tok, &tmptok, 0);
 	  if (tok == tmptok)
 	    error (_("Junk after task keyword."));
 	  if (!valid_task_id (*task))
 	    error (_("Unknown task %d."), *task);
+	  tok = tmptok;
 	}
       else if (rest)
 	{
@@ -10836,7 +10837,7 @@ is_masked_watchpoint (const struct breakpoint *b)
                 hw_read:   watch read, 
 		hw_access: watch access (read or write) */
 static void
-watch_command_1 (char *arg, int accessflag, int from_tty,
+watch_command_1 (const char *arg, int accessflag, int from_tty,
 		 int just_location, int internal)
 {
   volatile struct gdb_exception e;
@@ -10845,12 +10846,12 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
   const struct block *exp_valid_block = NULL, *cond_exp_valid_block = NULL;
   struct value *val, *mark, *result;
   struct frame_info *frame;
-  char *exp_start = NULL;
-  char *exp_end = NULL;
-  char *tok, *end_tok;
+  const char *exp_start = NULL;
+  const char *exp_end = NULL;
+  const char *tok, *end_tok;
   int toklen = -1;
-  char *cond_start = NULL;
-  char *cond_end = NULL;
+  const char *cond_start = NULL;
+  const char *cond_end = NULL;
   enum bptype bp_type;
   int thread = -1;
   int pc = 0;
@@ -10859,15 +10860,19 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
   int use_mask = 0;
   CORE_ADDR mask = 0;
   struct watchpoint *w;
+  char *expression;
+  struct cleanup *back_to;
 
   /* Make sure that we actually have parameters to parse.  */
   if (arg != NULL && arg[0] != '\0')
     {
-      char *value_start;
+      const char *value_start;
+
+      exp_end = arg + strlen (arg);
 
       /* Look for "parameter value" pairs at the end
 	 of the arguments string.  */
-      for (tok = arg + strlen (arg) - 1; tok > arg; tok--)
+      for (tok = exp_end - 1; tok > arg; tok--)
 	{
 	  /* Skip whitespace at the end of the argument list.  */
 	  while (tok > arg && (*tok == ' ' || *tok == '\t'))
@@ -10937,13 +10942,19 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
 
 	  /* Truncate the string and get rid of the "parameter value" pair before
 	     the arguments string is parsed by the parse_exp_1 function.  */
-	  *tok = '\0';
+	  exp_end = tok;
 	}
     }
+  else
+    exp_end = arg;
 
-  /* Parse the rest of the arguments.  */
+  /* Parse the rest of the arguments.  From here on out, everything
+     is in terms of a newly allocated string instead of the original
+     ARG.  */
   innermost_block = NULL;
-  exp_start = arg;
+  expression = savestring (arg, exp_end - arg);
+  back_to = make_cleanup (xfree, expression);
+  exp_start = arg = expression;
   exp = parse_exp_1 (&arg, 0, 0, 0);
   exp_end = arg;
   /* Remove trailing whitespace from the expression before saving it.
@@ -10989,8 +11000,8 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
   else if (val != NULL)
     release_value (val);
 
-  tok = skip_spaces (arg);
-  end_tok = skip_to_space (tok);
+  tok = skip_spaces_const (arg);
+  end_tok = skip_to_space_const (tok);
 
   toklen = end_tok - tok;
   if (toklen >= 1 && strncmp (tok, "if", toklen) == 0)
@@ -11142,6 +11153,7 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
     }
 
   install_breakpoint (internal, b, 1);
+  do_cleanups (back_to);
 }
 
 /* Return count of debug registers needed to watch the given expression.
@@ -14036,7 +14048,7 @@ update_breakpoint_locations (struct breakpoint *b,
 	 old symtab.  */
       if (b->cond_string != NULL)
 	{
-	  char *s;
+	  const char *s;
 	  volatile struct gdb_exception e;
 
 	  s = b->cond_string;
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 0d37d57..77da738 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -1113,20 +1113,22 @@ disassemble_command (char *arg, int from_tty)
   const char *name;
   CORE_ADDR pc;
   int flags;
+  const char *p;
 
+  p = arg;
   name = NULL;
   flags = 0;
 
-  if (arg && *arg == '/')
+  if (p && *p == '/')
     {
-      ++arg;
+      ++p;
 
-      if (*arg == '\0')
+      if (*p == '\0')
 	error (_("Missing modifier."));
 
-      while (*arg && ! isspace (*arg))
+      while (*p && ! isspace (*p))
 	{
-	  switch (*arg++)
+	  switch (*p++)
 	    {
 	    case 'm':
 	      flags |= DISASSEMBLY_SOURCE;
@@ -1139,20 +1141,20 @@ disassemble_command (char *arg, int from_tty)
 	    }
 	}
 
-      arg = skip_spaces (arg);
+      p = skip_spaces_const (p);
     }
 
-  if (! arg || ! *arg)
+  if (! p || ! *p)
     {
       flags |= DISASSEMBLY_OMIT_FNAME;
       disassemble_current_function (flags);
       return;
     }
 
-  pc = value_as_address (parse_to_comma_and_eval (&arg));
-  if (arg[0] == ',')
-    ++arg;
-  if (arg[0] == '\0')
+  pc = value_as_address (parse_to_comma_and_eval (&p));
+  if (p[0] == ',')
+    ++p;
+  if (p[0] == '\0')
     {
       /* One argument.  */
       if (find_pc_partial_function (pc, &name, &low, &high) == 0)
@@ -1172,13 +1174,13 @@ disassemble_command (char *arg, int from_tty)
       /* Two arguments.  */
       int incl_flag = 0;
       low = pc;
-      arg = skip_spaces (arg);
-      if (arg[0] == '+')
+      p = skip_spaces_const (p);
+      if (p[0] == '+')
 	{
-	  ++arg;
+	  ++p;
 	  incl_flag = 1;
 	}
-      high = parse_and_eval_address (arg);
+      high = parse_and_eval_address (p);
       if (incl_flag)
 	high += low;
     }
diff --git a/gdb/cli/cli-utils.c b/gdb/cli/cli-utils.c
index 933fb89..f74e6b1 100644
--- a/gdb/cli/cli-utils.c
+++ b/gdb/cli/cli-utils.c
@@ -237,8 +237,8 @@ skip_spaces_const (const char *chp)
 
 /* See documentation in cli-utils.h.  */
 
-char *
-skip_to_space (char *chp)
+const char *
+skip_to_space_const (const char *chp)
 {
   if (chp == NULL)
     return NULL;
diff --git a/gdb/cli/cli-utils.h b/gdb/cli/cli-utils.h
index 6f28e13..152fb89 100644
--- a/gdb/cli/cli-utils.h
+++ b/gdb/cli/cli-utils.h
@@ -101,7 +101,11 @@ extern const char *skip_spaces_const (const char *inp);
 /* Skip leading non-whitespace characters in INP, returning an updated
    pointer.  If INP is NULL, return NULL.  */
 
-extern char *skip_to_space (char *inp);
+#define skip_to_space(INP) ((char *) skip_to_space_const (INP))
+
+/* A const-correct version of the above.  */
+
+extern const char *skip_to_space_const (const char *inp);
 
 /* Reverse S to the last non-whitespace character without skipping past
    START.  */
diff --git a/gdb/common/format.c b/gdb/common/format.c
index 161ff55..5803818 100644
--- a/gdb/common/format.c
+++ b/gdb/common/format.c
@@ -28,11 +28,12 @@
 #include "format.h"
 
 struct format_piece *
-parse_format_string (char **arg)
+parse_format_string (const char **arg)
 {
-  char *s, *f, *string;
-  char *prev_start;
-  char *percent_loc;
+  const char *s;
+  char *f, *string;
+  const char *prev_start;
+  const char *percent_loc;
   char *sub_start, *current_substring;
   struct format_piece *pieces;
   int next_frag;
diff --git a/gdb/common/format.h b/gdb/common/format.h
index 7bd5b12..ba3d703 100644
--- a/gdb/common/format.h
+++ b/gdb/common/format.h
@@ -51,7 +51,7 @@ struct format_piece
 /* Return an array of printf fragments found at the given string, and
    rewrite ARG with a pointer to the end of the format string.  */
 
-extern struct format_piece *parse_format_string (char **arg);
+extern struct format_piece *parse_format_string (const char **arg);
 
 /* Given a pointer to an array of format pieces, free any memory that
    would have been allocated by parse_format_string.  */
diff --git a/gdb/eval.c b/gdb/eval.c
index d7f80e2..58c9e15 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -76,7 +76,7 @@ evaluate_subexp (struct type *expect_type, struct expression *exp,
    and return the result as a number.  */
 
 CORE_ADDR
-parse_and_eval_address (char *exp)
+parse_and_eval_address (const char *exp)
 {
   struct expression *expr = parse_expression (exp);
   CORE_ADDR addr;
@@ -104,7 +104,7 @@ parse_and_eval_long (char *exp)
 }
 
 struct value *
-parse_and_eval (char *exp)
+parse_and_eval (const char *exp)
 {
   struct expression *expr = parse_expression (exp);
   struct value *val;
@@ -121,7 +121,7 @@ parse_and_eval (char *exp)
    EXPP is advanced to point to the comma.  */
 
 struct value *
-parse_to_comma_and_eval (char **expp)
+parse_to_comma_and_eval (const char **expp)
 {
   struct expression *expr = parse_exp_1 (expp, 0, (struct block *) 0, 1);
   struct value *val;
diff --git a/gdb/expression.h b/gdb/expression.h
index 31f2420..eea47dc 100644
--- a/gdb/expression.h
+++ b/gdb/expression.h
@@ -95,12 +95,12 @@ struct expression
 
 /* From parse.c */
 
-extern struct expression *parse_expression (char *);
+extern struct expression *parse_expression (const char *);
 
 extern struct type *parse_expression_for_completion (char *, char **,
 						     enum type_code *);
 
-extern struct expression *parse_exp_1 (char **, CORE_ADDR pc,
+extern struct expression *parse_exp_1 (const char **, CORE_ADDR pc,
 				       const struct block *, int);
 
 /* For use by parsers; set if we want to parse an expression and
diff --git a/gdb/findcmd.c b/gdb/findcmd.c
index 07c1d4e..a8cda9b 100644
--- a/gdb/findcmd.c
+++ b/gdb/findcmd.c
@@ -69,7 +69,7 @@ parse_find_args (char *args, ULONGEST *max_countp,
   ULONGEST pattern_len;
   CORE_ADDR start_addr;
   ULONGEST search_space_len;
-  char *s = args;
+  const char *s = args;
   struct cleanup *old_cleanups;
   struct value *v;
 
@@ -110,7 +110,7 @@ parse_find_args (char *args, ULONGEST *max_countp,
 	    }
 	}
 
-      s = skip_spaces (s);
+      s = skip_spaces_const (s);
     }
 
   /* Get the search range.  */
@@ -120,7 +120,7 @@ parse_find_args (char *args, ULONGEST *max_countp,
 
   if (*s == ',')
     ++s;
-  s = skip_spaces (s);
+  s = skip_spaces_const (s);
 
   if (*s == '+')
     {
@@ -171,7 +171,7 @@ parse_find_args (char *args, ULONGEST *max_countp,
       struct type *t;
       ULONGEST pattern_buf_size_need;
 
-      s = skip_spaces (s);
+      s = skip_spaces_const (s);
 
       v = parse_to_comma_and_eval (&s);
       t = value_type (v);
@@ -219,7 +219,7 @@ parse_find_args (char *args, ULONGEST *max_countp,
 
       if (*s == ',')
 	++s;
-      s = skip_spaces (s);
+      s = skip_spaces_const (s);
     }
 
   if (pattern_buf_end == pattern_buf)
diff --git a/gdb/gdbserver/ax.c b/gdb/gdbserver/ax.c
index 386df3d..afeeaed 100644
--- a/gdb/gdbserver/ax.c
+++ b/gdb/gdbserver/ax.c
@@ -798,10 +798,10 @@ compile_bytecodes (struct agent_expr *aexpr)
    in.  */
 
 static void
-ax_printf (CORE_ADDR fn, CORE_ADDR chan, char *format,
+ax_printf (CORE_ADDR fn, CORE_ADDR chan, const char *format,
 	   int nargs, ULONGEST *args)
 {
-  char *f = format;
+  const char *f = format;
   struct format_piece *fpieces;
   int i, fp;
   char *current_substring;
diff --git a/gdb/linespec.c b/gdb/linespec.c
index 4fb49bb..9647d08 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -326,7 +326,7 @@ static void iterate_over_file_blocks (struct symtab *symtab,
 static void initialize_defaults (struct symtab **default_symtab,
 				 int *default_line);
 
-static CORE_ADDR linespec_expression_to_pc (char **exp_ptr);
+static CORE_ADDR linespec_expression_to_pc (const char **exp_ptr);
 
 static struct symtabs_and_lines decode_objc (struct linespec_state *self,
 					     linespec_p ls,
@@ -2181,7 +2181,8 @@ parse_linespec (linespec_parser *parser, char **argptr)
   /* It must be either LSTOKEN_STRING or LSTOKEN_NUMBER.  */
   if (token.type == LSTOKEN_STRING && *LS_TOKEN_STOKEN (token).ptr == '*')
     {
-      char *expr, *copy;
+      char *expr;
+      const char *copy;
 
       /* User specified an expression, *EXPR.  */
       copy = expr = copy_token_string (token);
@@ -2565,7 +2566,7 @@ initialize_defaults (struct symtab **default_symtab, int *default_line)
    advancing EXP_PTR past any parsed text.  */
 
 static CORE_ADDR
-linespec_expression_to_pc (char **exp_ptr)
+linespec_expression_to_pc (const char **exp_ptr)
 {
   if (current_program_space->executing_startup)
     /* The error message doesn't really matter, because this case
diff --git a/gdb/parse.c b/gdb/parse.c
index 09c378b..4c84b2b 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -1125,10 +1125,18 @@ prefixify_subexp (struct expression *inexpr,
    If COMMA is nonzero, stop if a comma is reached.  */
 
 struct expression *
-parse_exp_1 (char **stringptr, CORE_ADDR pc, const struct block *block,
+parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
 	     int comma)
 {
-  return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL);
+  struct expression *expr;
+  char *const_hack = *stringptr ? xstrdup (*stringptr) : NULL;
+  char *orig = const_hack;
+  struct cleanup *back_to = make_cleanup (xfree, const_hack);
+
+  expr = parse_exp_in_context (&const_hack, pc, block, comma, 0, NULL);
+  (*stringptr) += const_hack - orig;
+  do_cleanups (back_to);
+  return expr;
 }
 
 /* As for parse_exp_1, except that if VOID_CONTEXT_P, then
@@ -1264,7 +1272,7 @@ parse_exp_in_context (char **stringptr, CORE_ADDR pc, const struct block *block,
    to use up all of the contents of STRING.  */
 
 struct expression *
-parse_expression (char *string)
+parse_expression (const char *string)
 {
   struct expression *exp;
 
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index 155703d..695c180 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -2215,10 +2215,10 @@ printf_pointer (struct ui_file *stream, const char *format,
 /* printf "printf format string" ARG to STREAM.  */
 
 static void
-ui_printf (char *arg, struct ui_file *stream)
+ui_printf (const char *arg, struct ui_file *stream)
 {
   struct format_piece *fpieces;
-  char *s = arg;
+  const char *s = arg;
   struct value **val_args;
   int allocated_args = 20;
   struct cleanup *old_cleanups;
@@ -2229,7 +2229,7 @@ ui_printf (char *arg, struct ui_file *stream)
   if (s == 0)
     error_no_arg (_("format-control string and values to print"));
 
-  s = skip_spaces (s);
+  s = skip_spaces_const (s);
 
   /* A format string should follow, enveloped in double quotes.  */
   if (*s++ != '"')
@@ -2242,14 +2242,14 @@ ui_printf (char *arg, struct ui_file *stream)
   if (*s++ != '"')
     error (_("Bad format string, non-terminated '\"'."));
   
-  s = skip_spaces (s);
+  s = skip_spaces_const (s);
 
   if (*s != ',' && *s != 0)
     error (_("Invalid argument syntax"));
 
   if (*s == ',')
     s++;
-  s = skip_spaces (s);
+  s = skip_spaces_const (s);
 
   {
     int nargs = 0;
@@ -2267,7 +2267,7 @@ ui_printf (char *arg, struct ui_file *stream)
 
     while (*s != '\0')
       {
-	char *s1;
+	const char *s1;
 
 	if (nargs == allocated_args)
 	  val_args = (struct value **) xrealloc ((char *) val_args,
diff --git a/gdb/python/python.c b/gdb/python/python.c
index cd8ddfb..4a7cb28 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -720,11 +720,7 @@ gdbpy_parse_and_eval (PyObject *self, PyObject *args)
 
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
-      char *copy = xstrdup (expr_str);
-      struct cleanup *cleanup = make_cleanup (xfree, copy);
-
-      result = parse_and_eval (copy);
-      do_cleanups (cleanup);
+      result = parse_and_eval (expr_str);
     }
   GDB_PY_HANDLE_EXCEPTION (except);
 
diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
index 9eff137..7f27bc0 100644
--- a/gdb/tracepoint.c
+++ b/gdb/tracepoint.c
@@ -754,9 +754,12 @@ validate_actionline (char **line, struct breakpoint *b)
 	  tmp_p = p;
 	  for (loc = t->base.loc; loc; loc = loc->next)
 	    {
-	      p = tmp_p;
-	      exp = parse_exp_1 (&p, loc->address,
+	      const char *q;
+
+	      q = tmp_p;
+	      exp = parse_exp_1 (&q, loc->address,
 				 block_for_pc (loc->address), 1);
+	      p = (char *) q;
 	      old_chain = make_cleanup (free_current_contents, &exp);
 
 	      if (exp->elts[0].opcode == OP_VAR_VALUE)
@@ -806,10 +809,13 @@ validate_actionline (char **line, struct breakpoint *b)
 	  tmp_p = p;
 	  for (loc = t->base.loc; loc; loc = loc->next)
 	    {
-	      p = tmp_p;
+	      const char *q;
+
+	      q = tmp_p;
 	      /* Only expressions are allowed for this action.  */
-	      exp = parse_exp_1 (&p, loc->address,
+	      exp = parse_exp_1 (&q, loc->address,
 				 block_for_pc (loc->address), 1);
+	      p = (char *) q;
 	      old_chain = make_cleanup (free_current_contents, &exp);
 
 	      /* We have something to evaluate, make sure that the expr to
@@ -1470,9 +1476,12 @@ encode_actions_1 (struct command_line *action,
 		  unsigned long addr;
 		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
+		  const char *q;
 
-		  exp = parse_exp_1 (&action_exp, tloc->address,
+		  q = action_exp;
+		  exp = parse_exp_1 (&q, tloc->address,
 				     block_for_pc (tloc->address), 1);
+		  action_exp = (char *) q;
 		  old_chain = make_cleanup (free_current_contents, &exp);
 
 		  switch (exp->elts[0].opcode)
@@ -1561,9 +1570,12 @@ encode_actions_1 (struct command_line *action,
 		{
 		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
+		  const char *q;
 
-		  exp = parse_exp_1 (&action_exp, tloc->address,
+		  q = action_exp;
+		  exp = parse_exp_1 (&q, tloc->address,
 				     block_for_pc (tloc->address), 1);
+		  action_exp = (char *) q;
 		  old_chain = make_cleanup (free_current_contents, &exp);
 
 		  aexpr = gen_eval_for_expr (tloc->address, exp);
diff --git a/gdb/value.h b/gdb/value.h
index c10c3ec..d070d56 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -724,13 +724,13 @@ extern char *extract_field_op (struct expression *exp, int *subexp);
 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 						    int *, enum noside);
 
-extern struct value *parse_and_eval (char *exp);
+extern struct value *parse_and_eval (const char *exp);
 
-extern struct value *parse_to_comma_and_eval (char **expp);
+extern struct value *parse_to_comma_and_eval (const char **expp);
 
 extern struct type *parse_and_eval_type (char *p, int length);
 
-extern CORE_ADDR parse_and_eval_address (char *exp);
+extern CORE_ADDR parse_and_eval_address (const char *exp);
 
 extern LONGEST parse_and_eval_long (char *exp);
 
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 33ed7cf..8458836 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -620,7 +620,7 @@ varobj_create (char *objname,
       struct frame_info *fi;
       struct frame_id old_id = null_frame_id;
       struct block *block;
-      char *p;
+      const char *p;
       enum varobj_languages lang;
       struct value *value = NULL;
       volatile struct gdb_exception except;
@@ -1469,7 +1469,7 @@ varobj_set_value (struct varobj *var, char *expression)
   struct expression *exp;
   struct value *value = NULL; /* Initialize to keep gcc happy.  */
   int saved_input_radix = input_radix;
-  char *s = expression;
+  const char *s = expression;
   volatile struct gdb_exception except;
 
   gdb_assert (varobj_editable_p (var));