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ethminer
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Quadratic memory cost

cl-refactor
Paweł Bylica 10 years ago
parent
14d793a527
commit
e8a75a7327
1 changed files with 9 additions and 9 deletions
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  1. 18
      evmjit/libevmjit/Memory.cpp

18
evmjit/libevmjit/Memory.cpp
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@ -56,7 +56,7 @@ llvm::Function* Memory::getRequireFunc()
// BB "Check"
m_builder.SetInsertPoint(checkBB);
static const auto c_inputMax = uint64_t(2) << 40; // max value of blkSize and blkOffset that will not result in integer overflow in calculations below
static const auto c_inputMax = uint64_t(1) << 32; // max value of blkSize and blkOffset that will not result in integer overflow in calculations below
auto blkOffsetOk = m_builder.CreateICmpULE(blkOffset, Constant::get(c_inputMax), "blkOffsetOk");
auto blkO = m_builder.CreateSelect(blkOffsetOk, m_builder.CreateTrunc(blkOffset, Type::Size), m_builder.getInt64(c_inputMax), "bklO");
auto blkSizeOk = m_builder.CreateICmpULE(blkSize, Constant::get(c_inputMax), "blkSizeOk");
@ -72,15 +72,15 @@ llvm::Function* Memory::getRequireFunc()
// BB "Resize"
m_builder.SetInsertPoint(resizeBB);
// Check gas first
auto sizeExt = m_builder.CreateNUWSub(sizeReq, sizeCur, "sizeExt");
auto sizeSum = m_builder.CreateNUWAdd(sizeReq, sizeCur, "sizeSum");
auto costL = m_builder.CreateLShr(sizeExt, 5, "costL");
auto costQ1 = m_builder.CreateLShr(sizeExt, 20, "costQ1");
auto costQ2 = m_builder.CreateLShr(sizeSum, 20, "costQ2");
auto costQ = m_builder.CreateNUWAdd(costQ1, costQ2, "costQ");
auto cost = m_builder.CreateNUWAdd(costL, costQ, "cost");
auto w1 = m_builder.CreateLShr(sizeReq, 5);
auto w1s = m_builder.CreateNUWMul(w1, w1);
auto c1 = m_builder.CreateAdd(w1, m_builder.CreateLShr(w1s, 10));
auto w0 = m_builder.CreateLShr(sizeCur, 5);
auto w0s = m_builder.CreateNUWMul(w0, w0);
auto c0 = m_builder.CreateAdd(w0, m_builder.CreateLShr(w0s, 10));
auto cc = m_builder.CreateNUWSub(c1, c0);
auto costOk = m_builder.CreateAnd(blkOffsetOk, blkSizeOk, "costOk");
auto c = m_builder.CreateSelect(costOk, costL, m_builder.getInt64(std::numeric_limits<int64_t>::max()), "c");
auto c = m_builder.CreateSelect(costOk, cc, m_builder.getInt64(std::numeric_limits<int64_t>::max()), "c");
m_gasMeter.countMemory(c, jmpBuf, gas);
// Resize
m_memory.extend(mem, sizeReq);

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