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Diffstat (limited to 'compiler-rt/lib/xray/xray_interface.cc')
| -rw-r--r-- | compiler-rt/lib/xray/xray_interface.cc | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/compiler-rt/lib/xray/xray_interface.cc b/compiler-rt/lib/xray/xray_interface.cc deleted file mode 100644 index 997829e9358..00000000000 --- a/compiler-rt/lib/xray/xray_interface.cc +++ /dev/null @@ -1,179 +0,0 @@ -//===-- xray_interface.cpp --------------------------------------*- C++ -*-===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file is a part of XRay, a dynamic runtime instrumentation system. -// -// Implementation of the API functions. -// -//===----------------------------------------------------------------------===// - -#include "xray_interface_internal.h" -#include <atomic> -#include <cstdint> -#include <cstdio> -#include <errno.h> -#include <limits> -#include <sys/mman.h> - -namespace __xray { - -// This is the function to call when we encounter the entry or exit sleds. -std::atomic<void (*)(int32_t, XRayEntryType)> XRayPatchedFunction{nullptr}; - -} // namespace __xray - -extern "C" { -// The following functions have to be defined in assembler, on a per-platform -// basis. See xray_trampoline_*.s files for implementations. -extern void __xray_FunctionEntry(); -extern void __xray_FunctionExit(); -} - -extern std::atomic<bool> XRayInitialized; -extern std::atomic<__xray::XRaySledMap> XRayInstrMap; - -int __xray_set_handler(void (*entry)(int32_t, XRayEntryType)) { - if (XRayInitialized.load(std::memory_order_acquire)) { - __xray::XRayPatchedFunction.store(entry, std::memory_order_release); - return 1; - } - return 0; -} - -std::atomic<bool> XRayPatching{false}; - -XRayPatchingStatus __xray_patch() { - // FIXME: Make this happen asynchronously. For now just do this sequentially. - if (!XRayInitialized.load(std::memory_order_acquire)) - return XRayPatchingStatus::NOT_INITIALIZED; // Not initialized. - - static bool NotPatching = false; - if (!XRayPatching.compare_exchange_strong(NotPatching, true, - std::memory_order_acq_rel, - std::memory_order_acquire)) { - return XRayPatchingStatus::ONGOING; // Already patching. - } - - // Step 1: Compute the function id, as a unique identifier per function in the - // instrumentation map. - __xray::XRaySledMap InstrMap = XRayInstrMap.load(std::memory_order_acquire); - if (InstrMap.Entries == 0) - return XRayPatchingStatus::NOT_INITIALIZED; - - int32_t FuncId = 1; - static constexpr uint8_t CallOpCode = 0xe8; - static constexpr uint16_t MovR10Seq = 0xba41; - static constexpr uint8_t JmpOpCode = 0xe9; - uint64_t CurFun = 0; - for (std::size_t I = 0; I < InstrMap.Entries; I++) { - auto Sled = InstrMap.Sleds[I]; - auto F = Sled.Function; - if (CurFun == 0) - CurFun = F; - if (F != CurFun) { - ++FuncId; - CurFun = F; - } - - // While we're here, we should patch the nop sled. To do that we mprotect - // the page containing the function to be writeable. - void *PageAlignedAddr = - reinterpret_cast<void *>(Sled.Address & ~((2 << 16) - 1)); - std::size_t MProtectLen = - (Sled.Address + 12) - reinterpret_cast<uint64_t>(PageAlignedAddr); - if (mprotect(PageAlignedAddr, MProtectLen, - PROT_READ | PROT_WRITE | PROT_EXEC) == -1) { - printf("Failed mprotect: %d\n", errno); - return XRayPatchingStatus::FAILED; - } - - static constexpr int64_t MinOffset{std::numeric_limits<int32_t>::min()}; - static constexpr int64_t MaxOffset{std::numeric_limits<int32_t>::max()}; - if (Sled.Kind == XRayEntryType::ENTRY) { - // Here we do the dance of replacing the following sled: - // - // xray_sled_n: - // jmp +9 - // <9 byte nop> - // - // With the following: - // - // mov r10d, <function id> - // call <relative 32bit offset to entry trampoline> - // - // We need to do this in the following order: - // - // 1. Put the function id first, 2 bytes from the start of the sled (just - // after the 2-byte jmp instruction). - // 2. Put the call opcode 6 bytes from the start of the sled. - // 3. Put the relative offset 7 bytes from the start of the sled. - // 4. Do an atomic write over the jmp instruction for the "mov r10d" - // opcode and first operand. - // - // Prerequisite is to compute the relative offset to the - // __xray_FunctionEntry function's address. - int64_t TrampolineOffset = - reinterpret_cast<int64_t>(__xray_FunctionEntry) - - (static_cast<int64_t>(Sled.Address) + 11); - if (TrampolineOffset < MinOffset || TrampolineOffset > MaxOffset) { - // FIXME: Print out an error here. - continue; - } - *reinterpret_cast<uint32_t *>(Sled.Address + 2) = FuncId; - *reinterpret_cast<uint8_t *>(Sled.Address + 6) = CallOpCode; - *reinterpret_cast<uint32_t *>(Sled.Address + 7) = TrampolineOffset; - std::atomic_store_explicit( - reinterpret_cast<std::atomic<uint16_t> *>(Sled.Address), MovR10Seq, - std::memory_order_release); - } - - if (Sled.Kind == XRayEntryType::EXIT) { - // Here we do the dance of replacing the following sled: - // - // xray_sled_n: - // ret - // <10 byte nop> - // - // With the following: - // - // mov r10d, <function id> - // jmp <relative 32bit offset to exit trampoline> - // - // 1. Put the function id first, 2 bytes from the start of the sled (just - // after the 1-byte ret instruction). - // 2. Put the jmp opcode 6 bytes from the start of the sled. - // 3. Put the relative offset 7 bytes from the start of the sled. - // 4. Do an atomic write over the jmp instruction for the "mov r10d" - // opcode and first operand. - // - // Prerequisite is to compute the relative offset fo the - // __xray_FunctionExit function's address. - int64_t TrampolineOffset = - reinterpret_cast<int64_t>(__xray_FunctionExit) - - (static_cast<int64_t>(Sled.Address) + 11); - if (TrampolineOffset < MinOffset || TrampolineOffset > MaxOffset) { - // FIXME: Print out an error here. - continue; - } - *reinterpret_cast<uint32_t *>(Sled.Address + 2) = FuncId; - *reinterpret_cast<uint8_t *>(Sled.Address + 6) = JmpOpCode; - *reinterpret_cast<uint32_t *>(Sled.Address + 7) = TrampolineOffset; - std::atomic_store_explicit( - reinterpret_cast<std::atomic<uint16_t> *>(Sled.Address), MovR10Seq, - std::memory_order_release); - } - - if (mprotect(PageAlignedAddr, MProtectLen, PROT_READ | PROT_EXEC) == -1) { - printf("Failed mprotect: %d\n", errno); - return XRayPatchingStatus::FAILED; - } - } - XRayPatching.store(false, std::memory_order_release); - return XRayPatchingStatus::NOTIFIED; -} |
