Revert r276117 "[XRay] Basic initialization and flag definition for XRay runtime"

and also the follow-up "[xray] Only build xray on Linux for now"

Two build errors were reported on the llvm-commits list:

	[ 88%] Building CXX object lib/xray/CMakeFiles/clang_rt.xray-x86_64.dir/xray_flags.cc.o
	/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/projects/compiler-rt/lib/xray/xray_init.cc:23:10: fatal error: 'llvm/Support/ELF.h' file not found
  #include "llvm/Support/ELF.h"
					 ^

and

	In file included from /w/src/llvm.org/projects/compiler-rt/lib/xray/xray_interface.cc:16:
	/w/src/llvm.org/projects/compiler-rt/lib/xray/xray_interface_internal.h:36:8: error:
				no type named 'size_t' in namespace 'std'
		std::size_t Entries;
		~~~~~^

llvm-svn: 276186

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;
-}