Commit Graph

3 Commits

Author SHA1 Message Date
Davide Italiano 8eca282dc9 [LTO] Inherit options from Codegen before initializing TargetMachine.
This fixes bootstrap of llvm-tblgen (with LTO) and PR27150.
Slightly longer explanation follows.

Emission of .init_array instead of .ctors is supported only on a
subset of the Target LLVM supports. Codegen needs to be conservative
and always emit .ctors unless instructed otherwise (based on target).
If the dynamic linker sees .init_array it completely ignores
what's inside .ctors and therefore some constructors are not called
(and this causes llvm-tblgen to crash on startup).

Teach LLD/LTO about the Codegen options so we end up always emitting
.init_array and avoid this issue.
In future, we might end up supporting mix of .ctors and .init_array
in different input files if this shows up as a real-world use case.
The way gold handles this case is mapping .ctors from input into
.init_array in output. There's also another caveat because
as far as I understand .ctors run in reverse order so when we do
the copy/mapping we need to reverse copy in the output if there's
more than one ctor. That's why I'd rather avoid this complicate logic
unless there's a real need.

An analogous reasoning holds for .dtors/.fini_array.

llvm-svn: 265085
2016-04-01 00:35:29 +00:00
Davide Italiano e043c0c68c [LTO] Test lto passes are actually working.
This should have been part of r263761.

llvm-svn: 263763
2016-03-17 23:36:31 +00:00
Sean Silva b1b5cc83f1 [lto] Make sure that ctors are added to the combined module.
Summary:
More generally, appending linkage is a special case that we don't want
to create a SymbolBody for.

Reviewers: rafael, ruiu

Subscribers: Bigcheese, llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D18012

llvm-svn: 263179
2016-03-11 00:50:05 +00:00