On Saturday, 8 April 2017 at 21:31:31 UTC, Joseph Rushton
Wakeling wrote:
Hello folks,
The default dmd.conf settings for 64-bit environments include
the -fPIC flag (for good reason), but the settings for 32-bit
environments do not. Any particular reason for this?
Thanks & best wishes,
-- Joe
32 bit modes support for PIC is painful because the RIP relative
addressing mode does not exist. AMD introduced it when they added
64 bit support in the Opteron processors. In 32 bit mode it was
possible to generate PIC code but it required some ugly hacks
(CALL 0) which broke some hardware optimization (the return
address target cache) and adds a layer of indirection for shared
libraries (GOT), which had the consequence of breaking the
sharing, i.e. .so and .dll weren't really shared in 32 bit mode.
Here an in depth article that I haven't yet read but seem to be
interesting on the subject
https://www.technovelty.org/c/position-independent-code-and-x86-64-libraries.html
Of course, this has nothing to do with D per se.
