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//===--- JITLinkMemoryManager.cpp - JITLinkMemoryManager implementation ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/JITLink/JITLinkMemoryManager.h"
#include "llvm/Support/Process.h"
namespace llvm {
namespace jitlink {
JITLinkMemoryManager::~JITLinkMemoryManager() = default;
JITLinkMemoryManager::Allocation::~Allocation() = default;
Expected<std::unique_ptr<JITLinkMemoryManager::Allocation>>
InProcessMemoryManager::allocate(const JITLinkDylib *JD,
const SegmentsRequestMap &Request) {
using AllocationMap = DenseMap<unsigned, sys::MemoryBlock>;
// Local class for allocation.
class IPMMAlloc : public Allocation {
public:
IPMMAlloc(AllocationMap SegBlocks) : SegBlocks(std::move(SegBlocks)) {}
MutableArrayRef<char> getWorkingMemory(ProtectionFlags Seg) override {
assert(SegBlocks.count(Seg) && "No allocation for segment");
return {static_cast<char *>(SegBlocks[Seg].base()),
SegBlocks[Seg].allocatedSize()};
}
JITTargetAddress getTargetMemory(ProtectionFlags Seg) override {
assert(SegBlocks.count(Seg) && "No allocation for segment");
return pointerToJITTargetAddress(SegBlocks[Seg].base());
}
void finalizeAsync(FinalizeContinuation OnFinalize) override {
OnFinalize(applyProtections());
}
Error deallocate() override {
if (SegBlocks.empty())
return Error::success();
void *SlabStart = SegBlocks.begin()->second.base();
char *SlabEnd = (char *)SlabStart;
for (auto &KV : SegBlocks) {
SlabStart = std::min(SlabStart, KV.second.base());
SlabEnd = std::max(SlabEnd, (char *)(KV.second.base()) +
KV.second.allocatedSize());
}
size_t SlabSize = SlabEnd - (char *)SlabStart;
assert((SlabSize % sys::Process::getPageSizeEstimate()) == 0 &&
"Slab size is not a multiple of page size");
sys::MemoryBlock Slab(SlabStart, SlabSize);
if (auto EC = sys::Memory::releaseMappedMemory(Slab))
return errorCodeToError(EC);
return Error::success();
}
private:
Error applyProtections() {
for (auto &KV : SegBlocks) {
auto &Prot = KV.first;
auto &Block = KV.second;
if (auto EC = sys::Memory::protectMappedMemory(Block, Prot))
return errorCodeToError(EC);
if (Prot & sys::Memory::MF_EXEC)
sys::Memory::InvalidateInstructionCache(Block.base(),
Block.allocatedSize());
}
return Error::success();
}
AllocationMap SegBlocks;
};
if (!isPowerOf2_64((uint64_t)sys::Process::getPageSizeEstimate()))
return make_error<StringError>("Page size is not a power of 2",
inconvertibleErrorCode());
AllocationMap Blocks;
const sys::Memory::ProtectionFlags ReadWrite =
static_cast<sys::Memory::ProtectionFlags>(sys::Memory::MF_READ |
sys::Memory::MF_WRITE);
// Compute the total number of pages to allocate.
size_t TotalSize = 0;
for (auto &KV : Request) {
const auto &Seg = KV.second;
if (Seg.getAlignment() > sys::Process::getPageSizeEstimate())
return make_error<StringError>("Cannot request higher than page "
"alignment",
inconvertibleErrorCode());
TotalSize = alignTo(TotalSize, sys::Process::getPageSizeEstimate());
TotalSize += Seg.getContentSize();
TotalSize += Seg.getZeroFillSize();
}
// Allocate one slab to cover all the segments.
std::error_code EC;
auto SlabRemaining =
sys::Memory::allocateMappedMemory(TotalSize, nullptr, ReadWrite, EC);
if (EC)
return errorCodeToError(EC);
// Allocate segment memory from the slab.
for (auto &KV : Request) {
const auto &Seg = KV.second;
uint64_t SegmentSize = alignTo(Seg.getContentSize() + Seg.getZeroFillSize(),
sys::Process::getPageSizeEstimate());
assert(SlabRemaining.allocatedSize() >= SegmentSize &&
"Mapping exceeds allocation");
sys::MemoryBlock SegMem(SlabRemaining.base(), SegmentSize);
SlabRemaining = sys::MemoryBlock((char *)SlabRemaining.base() + SegmentSize,
SlabRemaining.allocatedSize() - SegmentSize);
// Zero out the zero-fill memory.
memset(static_cast<char *>(SegMem.base()) + Seg.getContentSize(), 0,
Seg.getZeroFillSize());
// Record the block for this segment.
Blocks[KV.first] = std::move(SegMem);
}
return std::unique_ptr<InProcessMemoryManager::Allocation>(
new IPMMAlloc(std::move(Blocks)));
}
} // end namespace jitlink
} // end namespace llvm
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