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author | Evan Cheng <evan.cheng@apple.com> | 2012-02-28 06:42:03 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2012-02-28 06:42:03 +0000 |
commit | ec52aaa12f57896fc806e849fa21a61603050ac4 (patch) | |
tree | 6c4c80ccf055e5a0cf0ab3a4a63e70868a5ba059 /lib/Target/MBlaze | |
parent | 1f5952352146f229cbc249405fbe9898d168089b (diff) | |
download | external_llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.zip external_llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.tar.gz external_llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.tar.bz2 |
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
Diffstat (limited to 'lib/Target/MBlaze')
-rw-r--r-- | lib/Target/MBlaze/MBlazeISelLowering.cpp | 2 | ||||
-rw-r--r-- | lib/Target/MBlaze/MBlazeISelLowering.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/lib/Target/MBlaze/MBlazeISelLowering.cpp b/lib/Target/MBlaze/MBlazeISelLowering.cpp index 4b5e82d..23c8e13 100644 --- a/lib/Target/MBlaze/MBlazeISelLowering.cpp +++ b/lib/Target/MBlaze/MBlazeISelLowering.cpp @@ -682,7 +682,7 @@ static bool CC_MBlaze_AssignReg(unsigned &ValNo, MVT &ValVT, MVT &LocVT, /// TODO: isVarArg, isTailCall. SDValue MBlazeTargetLowering:: LowerCall(SDValue Chain, SDValue Callee, CallingConv::ID CallConv, - bool isVarArg, bool &isTailCall, + bool isVarArg, bool doesNotRet, bool &isTailCall, const SmallVectorImpl<ISD::OutputArg> &Outs, const SmallVectorImpl<SDValue> &OutVals, const SmallVectorImpl<ISD::InputArg> &Ins, diff --git a/lib/Target/MBlaze/MBlazeISelLowering.h b/lib/Target/MBlaze/MBlazeISelLowering.h index 8b49bc3..168694b 100644 --- a/lib/Target/MBlaze/MBlazeISelLowering.h +++ b/lib/Target/MBlaze/MBlazeISelLowering.h @@ -134,7 +134,7 @@ namespace llvm { virtual SDValue LowerCall(SDValue Chain, SDValue Callee, CallingConv::ID CallConv, bool isVarArg, - bool &isTailCall, + bool doesNotRet, bool &isTailCall, const SmallVectorImpl<ISD::OutputArg> &Outs, const SmallVectorImpl<SDValue> &OutVals, const SmallVectorImpl<ISD::InputArg> &Ins, |