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[SectionMemoryManager] Abstract out mmap, munmap, mprotect even more …
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…; NFC

Summary:
This will let ORC JIT clients plug in custom logic for the mmap, munmap and
mprotect paths.

Reviewers: loladiro, dblaikie

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D39300

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317770 91177308-0d34-0410-b5e6-96231b3b80d8
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@sanjoy
sanjoy committed Nov 9, 2017
1 parent 7595e4c commit 5a61b4e
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Showing 2 changed files with 140 additions and 29 deletions.
75 changes: 71 additions & 4 deletions include/llvm/ExecutionEngine/SectionMemoryManager.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,9 +40,75 @@ namespace llvm {
/// directly. Clients of MCJIT should call MCJIT::finalizeObject.
class SectionMemoryManager : public RTDyldMemoryManager {
public:
SectionMemoryManager() = default;
SectionMemoryManager(const SectionMemoryManager&) = delete;
void operator=(const SectionMemoryManager&) = delete;
/// This enum describes the various reasons to allocate pages from
/// allocateMappedMemory.
enum class AllocationPurpose {
Code,
ROData,
RWData,
};

/// Implementations of this interface are used by SectionMemoryManager to
/// request pages from the operating system.
class MemoryMapper {
public:
/// This method attempts to allocate \p NumBytes bytes of virtual memory for
/// \p Purpose. \p NearBlock may point to an existing allocation, in which
/// case an attempt is made to allocate more memory near the existing block.
/// The actual allocated address is not guaranteed to be near the requested
/// address. \p Flags is used to set the initial protection flags for the
/// block of the memory. \p EC [out] returns an object describing any error
/// that occurs.
///
/// This method may allocate more than the number of bytes requested. The
/// actual number of bytes allocated is indicated in the returned
/// MemoryBlock.
///
/// The start of the allocated block must be aligned with the system
/// allocation granularity (64K on Windows, page size on Linux). If the
/// address following \p NearBlock is not so aligned, it will be rounded up
/// to the next allocation granularity boundary.
///
/// \r a non-null MemoryBlock if the function was successful, otherwise a
/// null MemoryBlock with \p EC describing the error.
virtual sys::MemoryBlock
allocateMappedMemory(AllocationPurpose Purpose, size_t NumBytes,
const sys::MemoryBlock *const NearBlock,
unsigned Flags, std::error_code &EC) = 0;

/// This method sets the protection flags for a block of memory to the state
/// specified by \p Flags. The behavior is not specified if the memory was
/// not allocated using the allocateMappedMemory method.
/// \p Block describes the memory block to be protected.
/// \p Flags specifies the new protection state to be assigned to the block.
///
/// If \p Flags is MF_WRITE, the actual behavior varies with the operating
/// system (i.e. MF_READ | MF_WRITE on Windows) and the target architecture
/// (i.e. MF_WRITE -> MF_READ | MF_WRITE on i386).
///
/// \r error_success if the function was successful, or an error_code
/// describing the failure if an error occurred.
virtual std::error_code protectMappedMemory(const sys::MemoryBlock &Block,
unsigned Flags) = 0;

/// This method releases a block of memory that was allocated with the
/// allocateMappedMemory method. It should not be used to release any memory
/// block allocated any other way.
/// \p Block describes the memory to be released.
///
/// \r error_success if the function was successful, or an error_code
/// describing the failure if an error occurred.
virtual std::error_code releaseMappedMemory(sys::MemoryBlock &M) = 0;

virtual ~MemoryMapper();
};

/// Creates a SectionMemoryManager instance with \p MM as the associated
/// memory mapper. If \p MM is nullptr then a default memory mapper is used
/// that directly calls into the operating system.
SectionMemoryManager(MemoryMapper *MM = nullptr);
SectionMemoryManager(const SectionMemoryManager &) = delete;
void operator=(const SectionMemoryManager &) = delete;
~SectionMemoryManager() override;

/// \brief Allocates a memory block of (at least) the given size suitable for
Expand Down Expand Up @@ -110,7 +176,7 @@ class SectionMemoryManager : public RTDyldMemoryManager {
sys::MemoryBlock Near;
};

uint8_t *allocateSection(MemoryGroup &MemGroup, uintptr_t Size,
uint8_t *allocateSection(AllocationPurpose Purpose, uintptr_t Size,
unsigned Alignment);

std::error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup,
Expand All @@ -119,6 +185,7 @@ class SectionMemoryManager : public RTDyldMemoryManager {
MemoryGroup CodeMem;
MemoryGroup RWDataMem;
MemoryGroup RODataMem;
MemoryMapper &MMapper;
};

} // end namespace llvm
Expand Down
94 changes: 69 additions & 25 deletions lib/ExecutionEngine/SectionMemoryManager.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,28 +25,42 @@ uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
StringRef SectionName,
bool IsReadOnly) {
if (IsReadOnly)
return allocateSection(RODataMem, Size, Alignment);
return allocateSection(RWDataMem, Size, Alignment);
return allocateSection(SectionMemoryManager::AllocationPurpose::ROData,
Size, Alignment);
return allocateSection(SectionMemoryManager::AllocationPurpose::RWData, Size,
Alignment);
}

uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID,
StringRef SectionName) {
return allocateSection(CodeMem, Size, Alignment);
return allocateSection(SectionMemoryManager::AllocationPurpose::Code, Size,
Alignment);
}

uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
uintptr_t Size,
unsigned Alignment) {
uint8_t *SectionMemoryManager::allocateSection(
SectionMemoryManager::AllocationPurpose Purpose, uintptr_t Size,
unsigned Alignment) {
if (!Alignment)
Alignment = 16;

assert(!(Alignment & (Alignment - 1)) && "Alignment must be a power of two.");

uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1)/Alignment + 1);
uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1) / Alignment + 1);
uintptr_t Addr = 0;

MemoryGroup &MemGroup = [&]() -> MemoryGroup & {
switch (Purpose) {
case AllocationPurpose::Code:
return CodeMem;
case AllocationPurpose::ROData:
return RODataMem;
case AllocationPurpose::RWData:
return RWDataMem;
}
}();

// Look in the list of free memory regions and use a block there if one
// is available.
for (FreeMemBlock &FreeMB : MemGroup.FreeMem) {
Expand All @@ -64,13 +78,16 @@ uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
// modify it rather than creating a new one
FreeMB.PendingPrefixIndex = MemGroup.PendingMem.size() - 1;
} else {
sys::MemoryBlock &PendingMB = MemGroup.PendingMem[FreeMB.PendingPrefixIndex];
PendingMB = sys::MemoryBlock(PendingMB.base(), Addr + Size - (uintptr_t)PendingMB.base());
sys::MemoryBlock &PendingMB =
MemGroup.PendingMem[FreeMB.PendingPrefixIndex];
PendingMB = sys::MemoryBlock(PendingMB.base(),
Addr + Size - (uintptr_t)PendingMB.base());
}

// Remember how much free space is now left in this block
FreeMB.Free = sys::MemoryBlock((void *)(Addr + Size), EndOfBlock - Addr - Size);
return (uint8_t*)Addr;
FreeMB.Free =
sys::MemoryBlock((void *)(Addr + Size), EndOfBlock - Addr - Size);
return (uint8_t *)Addr;
}
}

Expand All @@ -84,11 +101,9 @@ uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
// FIXME: Initialize the Near member for each memory group to avoid
// interleaving.
std::error_code ec;
sys::MemoryBlock MB = sys::Memory::allocateMappedMemory(RequiredSize,
&MemGroup.Near,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
ec);
sys::MemoryBlock MB = MMapper.allocateMappedMemory(
Purpose, RequiredSize, &MemGroup.Near,
sys::Memory::MF_READ | sys::Memory::MF_WRITE, ec);
if (ec) {
// FIXME: Add error propagation to the interface.
return nullptr;
Expand All @@ -110,20 +125,19 @@ uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,

// The allocateMappedMemory may allocate much more memory than we need. In
// this case, we store the unused memory as a free memory block.
unsigned FreeSize = EndOfBlock-Addr-Size;
unsigned FreeSize = EndOfBlock - Addr - Size;
if (FreeSize > 16) {
FreeMemBlock FreeMB;
FreeMB.Free = sys::MemoryBlock((void*)(Addr + Size), FreeSize);
FreeMB.Free = sys::MemoryBlock((void *)(Addr + Size), FreeSize);
FreeMB.PendingPrefixIndex = (unsigned)-1;
MemGroup.FreeMem.push_back(FreeMB);
}

// Return aligned address
return (uint8_t*)Addr;
return (uint8_t *)Addr;
}

bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg)
{
bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg) {
// FIXME: Should in-progress permissions be reverted if an error occurs?
std::error_code ec;

Expand Down Expand Up @@ -167,7 +181,8 @@ static sys::MemoryBlock trimBlockToPageSize(sys::MemoryBlock M) {
TrimmedSize -= StartOverlap;
TrimmedSize -= TrimmedSize % PageSize;

sys::MemoryBlock Trimmed((void *)((uintptr_t)M.base() + StartOverlap), TrimmedSize);
sys::MemoryBlock Trimmed((void *)((uintptr_t)M.base() + StartOverlap),
TrimmedSize);

assert(((uintptr_t)Trimmed.base() % PageSize) == 0);
assert((Trimmed.size() % PageSize) == 0);
Expand All @@ -176,12 +191,11 @@ static sys::MemoryBlock trimBlockToPageSize(sys::MemoryBlock M) {
return Trimmed;
}


std::error_code
SectionMemoryManager::applyMemoryGroupPermissions(MemoryGroup &MemGroup,
unsigned Permissions) {
for (sys::MemoryBlock &MB : MemGroup.PendingMem)
if (std::error_code EC = sys::Memory::protectMappedMemory(MB, Permissions))
if (std::error_code EC = MMapper.protectMappedMemory(MB, Permissions))
return EC;

MemGroup.PendingMem.clear();
Expand Down Expand Up @@ -211,8 +225,38 @@ void SectionMemoryManager::invalidateInstructionCache() {
SectionMemoryManager::~SectionMemoryManager() {
for (MemoryGroup *Group : {&CodeMem, &RWDataMem, &RODataMem}) {
for (sys::MemoryBlock &Block : Group->AllocatedMem)
sys::Memory::releaseMappedMemory(Block);
MMapper.releaseMappedMemory(Block);
}
}

SectionMemoryManager::MemoryMapper::~MemoryMapper() {}

namespace {
// Trivial implementation of SectionMemoryManager::MemoryMapper that just calls
// into sys::Memory.
class DefaultMMapper final : public SectionMemoryManager::MemoryMapper {
public:
sys::MemoryBlock
allocateMappedMemory(SectionMemoryManager::AllocationPurpose Purpose,
size_t NumBytes, const sys::MemoryBlock *const NearBlock,
unsigned Flags, std::error_code &EC) override {
return sys::Memory::allocateMappedMemory(NumBytes, NearBlock, Flags, EC);
}

std::error_code protectMappedMemory(const sys::MemoryBlock &Block,
unsigned Flags) override {
return sys::Memory::protectMappedMemory(Block, Flags);
}

std::error_code releaseMappedMemory(sys::MemoryBlock &M) override {
return sys::Memory::releaseMappedMemory(M);
}
};

DefaultMMapper DefaultMMapperInstance;
} // namespace

SectionMemoryManager::SectionMemoryManager(MemoryMapper *MM)
: MMapper(MM ? *MM : DefaultMMapperInstance) {}

} // namespace llvm

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