Commit Graph

3 Commits

Author SHA1 Message Date
David Majnemer ebc741168b IR: Allow comdats to be applied to globals with internal linkage
Our verifier check for checking if a global has local linkage was too
strict.  Forbid private linkage but permit local linkage.

Object file formats permit this and forbidding it prevents elimination
of unused, internal, vftables under the MSVC ABI.

llvm-svn: 212900
2014-07-13 04:56:11 +00:00
David Majnemer ed33243e86 IR: Aliases don't belong to an explicit comdat
Aliases inherit their comdat from their aliasee, they don't have an
explicit comdat.

This fixes PR20279.

llvm-svn: 212732
2014-07-10 16:26:10 +00:00
David Majnemer dad0a645a7 IR: Add COMDATs to the IR
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.

This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.

Differential Revision: http://reviews.llvm.org/D4178

llvm-svn: 211920
2014-06-27 18:19:56 +00:00