std::error_code OrcX86_64::emitIndirectStubsBlock(IndirectStubsInfo &StubsInfo,
unsigned MinStubs,
void *InitialPtrVal) {
// Stub format is:
//
// .section __orc_stubs
// stub1:
// jmpq *ptr1(%rip)
// .byte 0xC4 ; <- Invalid opcode padding.
// .byte 0xF1
// stub2:
// jmpq *ptr2(%rip)
//
// ...
//
// .section __orc_ptrs
// ptr1:
// .quad 0x0
// ptr2:
// .quad 0x0
//
// ...
const unsigned StubSize = IndirectStubsInfo::StubSize;
// Emit at least MinStubs, rounded up to fill the pages allocated.
unsigned PageSize = sys::Process::getPageSize();
unsigned NumPages = ((MinStubs * StubSize) + (PageSize - 1)) / PageSize;
unsigned NumStubs = (NumPages * PageSize) / StubSize;
// Allocate memory for stubs and pointers in one call.
std::error_code EC;
auto StubsMem =
sys::OwningMemoryBlock(
sys::Memory::allocateMappedMemory(2 * NumPages * PageSize, nullptr,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
EC));
if (EC)
return EC;
// Create separate MemoryBlocks representing the stubs and pointers.
sys::MemoryBlock StubsBlock(StubsMem.base(), NumPages * PageSize);
sys::MemoryBlock PtrsBlock(static_cast<char*>(StubsMem.base()) +
NumPages * PageSize,
NumPages * PageSize);
// Populate the stubs page stubs and mark it executable.
uint64_t *Stub = reinterpret_cast<uint64_t*>(StubsBlock.base());
uint64_t PtrOffsetField =
static_cast<uint64_t>(NumPages * PageSize - 6) << 16;
for (unsigned I = 0; I < NumStubs; ++I)
Stub[I] = 0xF1C40000000025ff | PtrOffsetField;
if (auto EC = sys::Memory::protectMappedMemory(StubsBlock,
sys::Memory::MF_READ |
sys::Memory::MF_EXEC))
return EC;
// Initialize all pointers to point at FailureAddress.
void **Ptr = reinterpret_cast<void**>(PtrsBlock.base());
for (unsigned I = 0; I < NumStubs; ++I)
Ptr[I] = InitialPtrVal;
StubsInfo = IndirectStubsInfo(NumStubs, std::move(StubsMem));
return std::error_code();
}
Error OrcAArch64::emitIndirectStubsBlock(IndirectStubsInfo &StubsInfo,
unsigned MinStubs,
void *InitialPtrVal) {
// Stub format is:
//
// .section __orc_stubs
// stub1:
// ldr x0, ptr1 ; PC-rel load of ptr1
// br x0 ; Jump to resolver
// stub2:
// ldr x0, ptr2 ; PC-rel load of ptr2
// br x0 ; Jump to resolver
//
// ...
//
// .section __orc_ptrs
// ptr1:
// .quad 0x0
// ptr2:
// .quad 0x0
//
// ...
const unsigned StubSize = IndirectStubsInfo::StubSize;
// Emit at least MinStubs, rounded up to fill the pages allocated.
unsigned PageSize = sys::Process::getPageSize();
unsigned NumPages = ((MinStubs * StubSize) + (PageSize - 1)) / PageSize;
unsigned NumStubs = (NumPages * PageSize) / StubSize;
// Allocate memory for stubs and pointers in one call.
std::error_code EC;
auto StubsMem = sys::OwningMemoryBlock(sys::Memory::allocateMappedMemory(
2 * NumPages * PageSize, nullptr,
sys::Memory::MF_READ | sys::Memory::MF_WRITE, EC));
if (EC)
return errorCodeToError(EC);
// Create separate MemoryBlocks representing the stubs and pointers.
sys::MemoryBlock StubsBlock(StubsMem.base(), NumPages * PageSize);
sys::MemoryBlock PtrsBlock(static_cast<char *>(StubsMem.base()) +
NumPages * PageSize,
NumPages * PageSize);
// Populate the stubs page stubs and mark it executable.
uint64_t *Stub = reinterpret_cast<uint64_t *>(StubsBlock.base());
uint64_t PtrOffsetField = static_cast<uint64_t>(NumPages * PageSize)
<< 3;
for (unsigned I = 0; I < NumStubs; ++I)
Stub[I] = 0xd61f020058000010 | PtrOffsetField;
if (auto EC = sys::Memory::protectMappedMemory(
StubsBlock, sys::Memory::MF_READ | sys::Memory::MF_EXEC))
return errorCodeToError(EC);
// Initialize all pointers to point at FailureAddress.
void **Ptr = reinterpret_cast<void **>(PtrsBlock.base());
for (unsigned I = 0; I < NumStubs; ++I)
Ptr[I] = InitialPtrVal;
StubsInfo = IndirectStubsInfo(NumStubs, std::move(StubsMem));
return Error::success();
}