[binutils-gdb] gdb: make interp::m_name an `const char *`

[binutils-gdb] gdb: make interp::m_name an `const char *`

[Simon Marchi]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=5a8ac2cb96cdb6c470a2ad4dec6442a21aa7dae9

commit 5a8ac2cb96cdb6c470a2ad4dec6442a21aa7dae9
Author: Simon Marchi <simon.marchi@polymtl.ca>
Date:   Thu Mar 2 15:32:23 2023 -0500

    gdb: make interp::m_name an `const char *`
    
    I realized that the memory for interp names does not need to be
    allocated.  The name used to register interp factory functions is always
    a literal string, so has static storage duration.  If we change
    interp_lookup to pass that name instead of the string that it receives
    as a parameter (which does not always have static storage duration),
    then interps can simply store pointers to the name.
    
    So, change interp_lookup to pass `factory.name` rather than `name`.
    Change interp::m_name to be a `const char *` rather than an std::string.
    
    Change-Id: I0474d1f7b3512e7d172ccd73018aea927def3188
    Reviewed-By: Tom Tromey <tom@tromey.com>

Diff:
---
 gdb/interps.c |  8 +++-----
 gdb/interps.h | 12 ++++++------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/gdb/interps.c b/gdb/interps.c
index 12a0048d102..ee451f27a63 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -82,13 +82,11 @@ static struct interp *interp_lookup_existing (struct ui *ui,
 					      const char *name);
 
 interp::interp (const char *name)
-  : m_name (make_unique_xstrdup (name))
+  : m_name (name)
 {
 }
 
-interp::~interp ()
-{
-}
+interp::~interp () = default;
 
 /* An interpreter factory.  Maps an interpreter name to the factory
    function that instantiates an interpreter by that name.  */
@@ -235,7 +233,7 @@ interp_lookup (struct ui *ui, const char *name)
   for (const interp_factory &factory : interpreter_factories)
     if (strcmp (factory.name, name) == 0)
       {
-	interp = factory.func (name);
+	interp = factory.func (factory.name);
 	interp_add (ui, interp);
 	return interp;
       }
diff --git a/gdb/interps.h b/gdb/interps.h
index 01bec47550d..62f37951dde 100644
--- a/gdb/interps.h
+++ b/gdb/interps.h
@@ -32,7 +32,9 @@ typedef struct interp *(*interp_factory_func) (const char *name);
 /* Each interpreter kind (CLI, MI, etc.) registers itself with a call
    to this function, passing along its name, and a pointer to a
    function that creates a new instance of an interpreter with that
-   name.  */
+   name.
+
+   The memory for NAME must have static storage duration.  */
 extern void interp_factory_register (const char *name,
 				     interp_factory_func func);
 
@@ -76,13 +78,11 @@ public:
   { return false; }
 
   const char *name () const
-  {
-    return m_name.get ();
-  }
+  { return m_name; }
 
 private:
-  /* This is the name in "-i=" and "set interpreter".  */
-  gdb::unique_xmalloc_ptr<char> m_name;
+  /* The memory for this is static, it comes from literal strings (e.g. "cli").  */
+  const char *m_name;
 
 public:
   /* Interpreters are stored in a linked list, this is the next