Commit Graph

3 Commits

Author SHA1 Message Date
Bob Wilson
eb1641d54a Add LLVM support for Swift.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164899 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-29 21:43:49 +00:00
Daniel Dunbar
20bd5296ce Revert r151623 "Some ARM implementaions, e.g. A-series, does return stack prediction. ...", it is breaking the Clang build during the Compiler-RT part.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151630 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-28 15:36:07 +00:00
Evan Cheng
ec52aaa12f Some ARM implementaions, e.g. A-series, does return stack prediction. That is,
the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.

Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.

rdar://8979299


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151623 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-28 06:42:03 +00:00