Share get_image_name between gdb and gdbserver

This moves get_image_name to nat/windows-nat.c so that it can be
shared between gdb and gdbserver.

gdb/ChangeLog
2020-04-08  Tom Tromey  <tromey@adacore.com>

	* windows-nat.c (get_image_name): Move to nat/windows-nat.c.
	(handle_load_dll): Update.
	* nat/windows-nat.c (get_image_name): Move from windows-nat.c.

gdbserver/ChangeLog
2020-04-08  Tom Tromey  <tromey@adacore.com>

	* win32-low.c (get_image_name): Remove.
	(handle_load_dll): Update.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2020-04-08  Tom Tromey  <tromey@adacore.com>
+
+	* windows-nat.c (get_image_name): Move to nat/windows-nat.c.
+	(handle_load_dll): Update.
+	* nat/windows-nat.c (get_image_name): Move from windows-nat.c.
+
 2020-04-08  Tom Tromey  <tromey@adacore.com>
 
 	* windows-nat.c (enum thread_disposition_type): Move to

gdb/nat/windows-nat.c

@@ -69,4 +69,61 @@ windows_thread_info::resume ()
   suspended = 0;
 }
 
+const char *
+get_image_name (HANDLE h, void *address, int unicode)
+{
+#ifdef __CYGWIN__
+  static char buf[MAX_PATH];
+#else
+  static char buf[(2 * MAX_PATH) + 1];
+#endif
+  DWORD size = unicode ? sizeof (WCHAR) : sizeof (char);
+  char *address_ptr;
+  int len = 0;
+  char b[2];
+  SIZE_T done;
+
+  /* Attempt to read the name of the dll that was detected.
+     This is documented to work only when actively debugging
+     a program.  It will not work for attached processes.  */
+  if (address == NULL)
+    return NULL;
+
+#ifdef _WIN32_WCE
+  /* Windows CE reports the address of the image name,
+     instead of an address of a pointer into the image name.  */
+  address_ptr = address;
+#else
+  /* See if we could read the address of a string, and that the
+     address isn't null.  */
+  if (!ReadProcessMemory (h, address,  &address_ptr,
+			  sizeof (address_ptr), &done)
+      || done != sizeof (address_ptr)
+      || !address_ptr)
+    return NULL;
+#endif
+
+  /* Find the length of the string.  */
+  while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done)
+	 && (b[0] != 0 || b[size - 1] != 0) && done == size)
+    continue;
+
+  if (!unicode)
+    ReadProcessMemory (h, address_ptr, buf, len, &done);
+  else
+    {
+      WCHAR *unicode_address = (WCHAR *) alloca (len * sizeof (WCHAR));
+      ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR),
+			 &done);
+#ifdef __CYGWIN__
+      wcstombs (buf, unicode_address, MAX_PATH);
+#else
+      WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, sizeof buf,
+			   0, 0);
+#endif
+    }
+
+  return buf;
+}
+
 }

gdb/nat/windows-nat.h

@@ -111,6 +111,13 @@ enum thread_disposition_type
 extern windows_thread_info *thread_rec (ptid_t ptid,
 					thread_disposition_type disposition);
 
+/* Return the name of the DLL referenced by H at ADDRESS.  UNICODE
+   determines what sort of string is read from the inferior.  Returns
+   the name of the DLL, or NULL on error.  If a name is returned, it
+   is stored in a static buffer which is valid until the next call to
+   get_image_name.  */
+extern const char *get_image_name (HANDLE h, void *address, int unicode);
+
 }
 
 #endif

gdb/windows-nat.c

@@ -921,56 +921,6 @@ windows_make_so (const char *name, LPVOID load_addr)
   return so;
 }
 
-static char *
-get_image_name (HANDLE h, void *address, int unicode)
-{
-#ifdef __CYGWIN__
-  static char buf[__PMAX];
-#else
-  static char buf[(2 * __PMAX) + 1];
-#endif
-  DWORD size = unicode ? sizeof (WCHAR) : sizeof (char);
-  char *address_ptr;
-  int len = 0;
-  char b[2];
-  SIZE_T done;
-
-  /* Attempt to read the name of the dll that was detected.
-     This is documented to work only when actively debugging
-     a program.  It will not work for attached processes.  */
-  if (address == NULL)
-    return NULL;
-
-  /* See if we could read the address of a string, and that the
-     address isn't null.  */
-  if (!ReadProcessMemory (h, address,  &address_ptr,
-			  sizeof (address_ptr), &done)
-      || done != sizeof (address_ptr) || !address_ptr)
-    return NULL;
-
-  /* Find the length of the string.  */
-  while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done)
-	 && (b[0] != 0 || b[size - 1] != 0) && done == size)
-    continue;
-
-  if (!unicode)
-    ReadProcessMemory (h, address_ptr, buf, len, &done);
-  else
-    {
-      WCHAR *unicode_address = (WCHAR *) alloca (len * sizeof (WCHAR));
-      ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR),
-			 &done);
-#ifdef __CYGWIN__
-      wcstombs (buf, unicode_address, __PMAX);
-#else
-      WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, sizeof buf,
-			   0, 0);
-#endif
-    }
-
-  return buf;
-}
-
 /* Handle a DLL load event, and return 1.
 
    This function assumes that this event did not occur during inferior
@@ -982,7 +932,7 @@ static void
 handle_load_dll ()
 {
   LOAD_DLL_DEBUG_INFO *event = &current_event.u.LoadDll;
-  char *dll_name;
+  const char *dll_name;
 
   /* Try getting the DLL name via the lpImageName field of the event.
      Note that Microsoft documents this fields as strictly optional,

gdbserver/ChangeLog

@@ -1,3 +1,8 @@
+2020-04-08  Tom Tromey  <tromey@adacore.com>
+
+	* win32-low.c (get_image_name): Remove.
+	(handle_load_dll): Update.
+
 2020-04-08  Tom Tromey  <tromey@adacore.com>
 
 	* win32-low.c (windows_nat::thread_rec): Rename from thread_rec.

gdbserver/win32-low.cc

@@ -1031,55 +1031,6 @@ win32_add_one_solib (const char *name, CORE_ADDR load_addr)
   loaded_dll (buf2, load_addr);
 }
 
-static char *
-get_image_name (HANDLE h, void *address, int unicode)
-{
-  static char buf[(2 * MAX_PATH) + 1];
-  DWORD size = unicode ? sizeof (WCHAR) : sizeof (char);
-  char *address_ptr;
-  int len = 0;
-  char b[2];
-  SIZE_T done;
-
-  /* Attempt to read the name of the dll that was detected.
-     This is documented to work only when actively debugging
-     a program.  It will not work for attached processes. */
-  if (address == NULL)
-    return NULL;
-
-#ifdef _WIN32_WCE
-  /* Windows CE reports the address of the image name,
-     instead of an address of a pointer into the image name.  */
-  address_ptr = address;
-#else
-  /* See if we could read the address of a string, and that the
-     address isn't null. */
-  if (!ReadProcessMemory (h, address,  &address_ptr,
-			  sizeof (address_ptr), &done)
-      || done != sizeof (address_ptr)
-      || !address_ptr)
-    return NULL;
-#endif
-
-  /* Find the length of the string */
-  while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done)
-	 && (b[0] != 0 || b[size - 1] != 0) && done == size)
-    continue;
-
-  if (!unicode)
-    ReadProcessMemory (h, address_ptr, buf, len, &done);
-  else
-    {
-      WCHAR *unicode_address = XALLOCAVEC (WCHAR, len);
-      ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR),
-			 &done);
-
-      WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, len, 0, 0);
-    }
-
-  return buf;
-}
-
 typedef BOOL (WINAPI *winapi_EnumProcessModules) (HANDLE, HMODULE *,
 						  DWORD, LPDWORD);
 typedef BOOL (WINAPI *winapi_GetModuleInformation) (HANDLE, HMODULE,
@@ -1188,7 +1139,7 @@ static void
 handle_load_dll (void)
 {
   LOAD_DLL_DEBUG_INFO *event = &current_event.u.LoadDll;
-  char *dll_name;
+  const char *dll_name;
 
   dll_name = get_image_name (current_process_handle,
 			     event->lpImageName, event->fUnicode);