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author | Owen Anderson <resistor@mac.com> | 2009-08-25 22:27:22 +0000 |
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committer | Owen Anderson <resistor@mac.com> | 2009-08-25 22:27:22 +0000 |
commit | d8110fb7264993f30133c532cd074313bead0afa (patch) | |
tree | a3746e283d0eea162864ae9054061d5d8f1bfee5 /lib/CodeGen/SelectionDAG | |
parent | 75b0edae7275436c1255c10eb98e5b0dffc978f6 (diff) | |
download | llvm-d8110fb7264993f30133c532cd074313bead0afa.tar.gz llvm-d8110fb7264993f30133c532cd074313bead0afa.tar.bz2 llvm-d8110fb7264993f30133c532cd074313bead0afa.tar.xz |
Get rid of this horrible "benign race" by exploiting ManagedStatic to initialize
the array on its first access.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80040 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG')
-rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index cbc4dc886c..11f12c9475 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -5014,8 +5014,20 @@ void SDNode::Profile(FoldingSetNodeID &ID) const { AddNodeIDNode(ID, this); } +namespace { + struct EVTArray { + std::vector<EVT> VTs; + + EVTArray() { + VTs.reserve(MVT::LAST_VALUETYPE); + for (unsigned i = 0; i < MVT::LAST_VALUETYPE; ++i) + VTs.push_back(MVT((MVT::SimpleValueType)i)); + } + }; +} + static ManagedStatic<std::set<EVT, EVT::compareRawBits> > EVTs; -static EVT VTs[MVT::LAST_VALUETYPE]; +static ManagedStatic<EVTArray> SimpleVTArray; static ManagedStatic<sys::SmartMutex<true> > VTMutex; /// getValueTypeList - Return a pointer to the specified value type. @@ -5025,12 +5037,7 @@ const EVT *SDNode::getValueTypeList(EVT VT) { sys::SmartScopedLock<true> Lock(*VTMutex); return &(*EVTs->insert(VT).first); } else { - // All writes to this location will have the same value, so it's ok - // to race on it. We only need to ensure that at least one write has - // succeeded before we return the pointer into the array. - VTs[VT.getSimpleVT().SimpleTy] = VT; - sys::MemoryFence(); - return VTs + VT.getSimpleVT().SimpleTy; + return &SimpleVTArray->VTs[VT.getSimpleVT().SimpleTy]; } } |