RFC: Ignore TLS symbols for non-TLS programs

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=185337

currently for trivia nonthreaded helloworld with no debug info up to -ggdb2 you
will get:
	(gdb) p errno 
	Cannot access memory at address 0x8 

* with -ggdb3 "errno" gets resolved as _macro_ and the resulting
  "(*__errno_location ())" expression is always fine.

* with -ggdb2 and less "errno" in fact does not exist anywhere as it was
  compiled to "(*__errno_location ())" and the macro definition is not present.
  Unfortunately gdb will find the TLS symbol and it will try to access it but
  as the program has been compiled without -lpthread the TLS base register
  (%gs on i386) is not setup and it will result in:
  	Cannot access memory at address 0x8

IMO the right way is to ignore TLS symbols for inferiors without activated
threading.  Patch attached.

Also attached suggestion patch how to deal with the most common "errno" symbol
for the most common under-ggdb3 compiled programs.


Regards,
Jan

Attachment: gdb-6.5-bz185337-tls-ignore-symbols-without-startup.patch
Description: Text document

Attachment: gdb-6.5-bz185337-missing-errno-suggestion.patch
Description: Text document