Fix dynamic linking on PPC64.
Dynamic linking on PPC64 has had problems since we had to move the top-down
hazard-detection logic post-ra. For dynamic linking to work there needs to be
a nop placed after every call. It turns out that it is really hard to guarantee
that nothing will be placed in between the call (bl) and the nop during post-ra
scheduling. Previous attempts at fixing this by placing logic inside the
hazard detector only partially worked.
This is now fixed in a different way: call+nop codegen-only instructions. As far
as CodeGen is concerned the pair is now a single instruction and cannot be split.
This solution works much better than previous attempts.
The scoreboard hazard detector is also renamed to be more generic, there is currently
no cpu-specific logic in it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153816 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index 7a8ec40..6f74828 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -51,7 +51,7 @@
unsigned Directive = TM->getSubtarget<PPCSubtarget>().getDarwinDirective();
if (Directive == PPC::DIR_440) {
const InstrItineraryData *II = TM->getInstrItineraryData();
- return new PPCHazardRecognizer440(II, DAG);
+ return new PPCScoreboardHazardRecognizer(II, DAG);
}
return TargetInstrInfoImpl::CreateTargetHazardRecognizer(TM, DAG);
@@ -684,6 +684,9 @@
case PPC::GC_LABEL:
case PPC::DBG_VALUE:
return 0;
+ case PPC::BL8_NOP_ELF:
+ case PPC::BLA8_NOP_ELF:
+ return 8;
default:
return 4; // PowerPC instructions are all 4 bytes
}