[compiler-rt] r276117 - [compiler-rt] [XRay] Basic initialization and flag definition for XRay runtime
Dean Michael Berris via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 20 07:14:51 PDT 2016
Author: dberris
Date: Wed Jul 20 09:14:50 2016
New Revision: 276117
URL: http://llvm.org/viewvc/llvm-project?rev=276117&view=rev
Log:
[compiler-rt] [XRay] Basic initialization and flag definition for XRay runtime
Summary:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).
Depends on D19904
Reviewers: echristo, kcc, rnk
Subscribers: rnk, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D21612
Added:
compiler-rt/trunk/include/xray/
compiler-rt/trunk/include/xray/xray_interface.h
compiler-rt/trunk/lib/xray/
compiler-rt/trunk/lib/xray/CMakeLists.txt
compiler-rt/trunk/lib/xray/xray_flags.cc
compiler-rt/trunk/lib/xray/xray_flags.h
compiler-rt/trunk/lib/xray/xray_flags.inc
compiler-rt/trunk/lib/xray/xray_init.cc
compiler-rt/trunk/lib/xray/xray_interface.cc
compiler-rt/trunk/lib/xray/xray_interface_internal.h
compiler-rt/trunk/lib/xray/xray_trampoline_x86.S
Modified:
compiler-rt/trunk/CMakeLists.txt
compiler-rt/trunk/cmake/config-ix.cmake
compiler-rt/trunk/include/CMakeLists.txt
compiler-rt/trunk/lib/CMakeLists.txt
Modified: compiler-rt/trunk/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/CMakeLists.txt?rev=276117&r1=276116&r2=276117&view=diff
==============================================================================
--- compiler-rt/trunk/CMakeLists.txt (original)
+++ compiler-rt/trunk/CMakeLists.txt Wed Jul 20 09:14:50 2016
@@ -37,6 +37,8 @@ option(COMPILER_RT_BUILD_BUILTINS "Build
mark_as_advanced(COMPILER_RT_BUILD_BUILTINS)
option(COMPILER_RT_BUILD_SANITIZERS "Build sanitizers" ON)
mark_as_advanced(COMPILER_RT_BUILD_SANITIZERS)
+option(COMPILER_RT_BUILD_XRAY "Build xray" ON)
+mark_as_advanced(COMPILER_RT_BUILD_XRAY)
if (COMPILER_RT_STANDALONE_BUILD)
if (NOT LLVM_CONFIG_PATH)
Modified: compiler-rt/trunk/cmake/config-ix.cmake
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/cmake/config-ix.cmake?rev=276117&r1=276116&r2=276117&view=diff
==============================================================================
--- compiler-rt/trunk/cmake/config-ix.cmake (original)
+++ compiler-rt/trunk/cmake/config-ix.cmake Wed Jul 20 09:14:50 2016
@@ -161,6 +161,7 @@ set(ALL_SAFESTACK_SUPPORTED_ARCH ${X86}
set(ALL_CFI_SUPPORTED_ARCH ${X86} ${X86_64} ${MIPS64})
set(ALL_ESAN_SUPPORTED_ARCH ${X86_64})
set(ALL_SCUDO_SUPPORTED_ARCH ${X86_64})
+set(ALL_XRAY_SUPPORTED_ARCH ${X86_64})
if(APPLE)
include(CompilerRTDarwinUtils)
@@ -350,6 +351,9 @@ if(APPLE)
list_intersect(SCUDO_SUPPORTED_ARCH
ALL_SCUDO_SUPPORTED_ARCH
SANITIZER_COMMON_SUPPORTED_ARCH)
+ list_intersect(XRAY_SUPPORTED_ARCH
+ ALL_XRAY_SUPPORTED_ARCH
+ SANITIZER_COMMON_SUPPORTED_ARCH)
else()
# Architectures supported by compiler-rt libraries.
filter_available_targets(SANITIZER_COMMON_SUPPORTED_ARCH
@@ -373,6 +377,7 @@ else()
filter_available_targets(ESAN_SUPPORTED_ARCH ${ALL_ESAN_SUPPORTED_ARCH})
filter_available_targets(SCUDO_SUPPORTED_ARCH
${ALL_SCUDO_SUPPORTED_ARCH})
+ filter_available_targets(XRAY_SUPPORTED_ARCH ${ALL_XRAY_SUPPORTED_ARCH})
endif()
if (MSVC)
Modified: compiler-rt/trunk/include/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/include/CMakeLists.txt?rev=276117&r1=276116&r2=276117&view=diff
==============================================================================
--- compiler-rt/trunk/include/CMakeLists.txt (original)
+++ compiler-rt/trunk/include/CMakeLists.txt Wed Jul 20 09:14:50 2016
@@ -10,11 +10,18 @@ set(SANITIZER_HEADERS
sanitizer/msan_interface.h
sanitizer/tsan_interface_atomic.h)
+set(XRAY_HEADERS
+ xray/xray_interface.h)
+
+set(COMPILER_RT_HEADERS
+ ${SANITIZER_HEADERS}
+ ${XRAY_HEADERS})
+
set(output_dir ${COMPILER_RT_OUTPUT_DIR}/include)
# Copy compiler-rt headers to the build tree.
set(out_files)
-foreach( f ${SANITIZER_HEADERS} )
+foreach( f ${COMPILER_RT_HEADERS} )
set( src ${CMAKE_CURRENT_SOURCE_DIR}/${f} )
set( dst ${output_dir}/${f} )
add_custom_command(OUTPUT ${dst}
@@ -32,3 +39,7 @@ set_target_properties(compiler-rt-header
install(FILES ${SANITIZER_HEADERS}
PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
DESTINATION ${COMPILER_RT_INSTALL_PATH}/include/sanitizer)
+# Install xray headers.
+install(FILES ${XRAY_HEADERS}
+ PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
+ DESTINATION ${COMPILER_RT_INSTALL_PATH}/include/xray)
Added: compiler-rt/trunk/include/xray/xray_interface.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/include/xray/xray_interface.h?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/include/xray/xray_interface.h (added)
+++ compiler-rt/trunk/include/xray/xray_interface.h Wed Jul 20 09:14:50 2016
@@ -0,0 +1,66 @@
+//===-- xray_interface.h ----------------------------------------*- 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.
+//
+// APIs for controlling XRay functionality explicitly.
+//===----------------------------------------------------------------------===//
+#ifndef XRAY_XRAY_INTERFACE_H
+#define XRAY_XRAY_INTERFACE_H
+
+#include <cstdint>
+
+extern "C" {
+
+enum XRayEntryType { ENTRY = 0, EXIT = 1 };
+
+// Provide a function to invoke for when instrumentation points are hit. This is
+// a user-visible control surface that overrides the default implementation. The
+// function provided should take the following arguments:
+//
+// - function id: an identifier that indicates the id of a function; this id
+// is generated by xray; the mapping between the function id
+// and the actual function pointer is available through
+// __xray_table.
+// - entry type: identifies what kind of instrumentation point was encountered
+// (function entry, function exit, etc.). See the enum
+// XRayEntryType for more details.
+//
+// Returns 1 on success, 0 on error.
+extern int __xray_set_handler(void (*entry)(int32_t, XRayEntryType));
+
+// This removes whatever the currently provided handler is. Returns 1 on
+// success, 0 on error.
+extern int __xray_remove_handler();
+
+enum XRayPatchingStatus {
+ NOT_INITIALIZED = 0,
+ NOTIFIED = 1,
+ ONGOING = 2,
+ FAILED = 3
+};
+
+// This tells XRay to patch the instrumentation points. This is an asynchronous
+// process, and returns the following status in specific cases:
+//
+// - 0 : XRay is not initialized.
+// - 1 : We've done the notification.
+// - 2 : Patching / un-patching is on-going.
+extern XRayPatchingStatus __xray_patch();
+
+// Reverses the effect of __xray_patch(). This is an asynchronous process, and
+// returns the following status in specific cases.
+//
+// - 0 : XRay is not initialized.
+// - 1 : We've done the notification.
+// - 2 : Patching / un-patching is on-going.
+extern int __xray_unpatch();
+}
+
+#endif
Modified: compiler-rt/trunk/lib/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/CMakeLists.txt?rev=276117&r1=276116&r2=276117&view=diff
==============================================================================
--- compiler-rt/trunk/lib/CMakeLists.txt (original)
+++ compiler-rt/trunk/lib/CMakeLists.txt Wed Jul 20 09:14:50 2016
@@ -57,3 +57,7 @@ if(COMPILER_RT_BUILD_SANITIZERS)
add_subdirectory(scudo)
endif()
endif()
+
+if(COMPILER_RT_BUILD_XRAY)
+ add_subdirectory(xray)
+endif()
Added: compiler-rt/trunk/lib/xray/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/CMakeLists.txt?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/CMakeLists.txt (added)
+++ compiler-rt/trunk/lib/xray/CMakeLists.txt Wed Jul 20 09:14:50 2016
@@ -0,0 +1,47 @@
+# Build for the XRay runtime support library.
+
+set(XRAY_SOURCES
+ xray_init.cc
+ xray_interface.cc
+ xray_flags.cc
+)
+
+set(x86_64_SOURCES
+ xray_trampoline_x86.S
+ ${XRAY_SOURCES})
+
+include_directories(..)
+include_directories(../../include)
+
+set(XRAY_CFLAGS ${SANITIZER_COMMON_CFLAGS})
+
+set(XRAY_COMMON_DEFINITIONS XRAY_HAS_EXCEPTIONS=1)
+
+add_compiler_rt_object_libraries(RTXray
+ ARCHS ${XRAY_SUPPORTED_ARCH}
+ SOURCES ${XRAY_SOURCES} CFLAGS ${XRAY_CFLAGS}
+ DEFS ${XRAY_COMMON_DEFINITIONS})
+
+add_custom_target(xray)
+set(XRAY_COMMON_RUNTIME_OBJECT_LIBS
+ RTSanitizerCommon
+ RTSanitizerCommonLibc)
+
+foreach (arch ${XRAY_SUPPORTED_ARCH})
+ if (CAN_TARGET_${arch})
+ add_compiler_rt_runtime(clang_rt.xray
+ STATIC
+ ARCHS ${arch}
+ SOURCES ${${arch}_SOURCES}
+ CFLAGS ${XRAY_CFLAGS}
+ DEFS ${XRAY_COMMON_DEFINITIONS}
+ OBJECT_LIBS ${XRAY_COMMON_RUNTIME_OBJECT_LIBS}
+ PARENT_TARGET xray)
+ endif ()
+endforeach()
+
+add_dependencies(compiler-rt xray)
+
+# if(COMPILER_RT_INCLUDE_TESTS)
+# add_subdirectory(tests)
+# endif()
Added: compiler-rt/trunk/lib/xray/xray_flags.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_flags.cc?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_flags.cc (added)
+++ compiler-rt/trunk/lib/xray/xray_flags.cc Wed Jul 20 09:14:50 2016
@@ -0,0 +1,61 @@
+//===-- xray_flags.cc -------------------------------------------*- 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.
+//
+// XRay flag parsing logic.
+//===----------------------------------------------------------------------===//
+
+#include "xray_flags.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flag_parser.h"
+#include "sanitizer_common/sanitizer_libc.h"
+
+using namespace __sanitizer;
+
+namespace __xray {
+
+Flags xray_flags_dont_use_directly; // use via flags().
+
+void Flags::SetDefaults() {
+#define XRAY_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
+#include "xray_flags.inc"
+#undef XRAY_FLAG
+}
+
+static void RegisterXRayFlags(FlagParser *P, Flags *F) {
+#define XRAY_FLAG(Type, Name, DefaultValue, Description) \
+ RegisterFlag(P, #Name, Description, &F->Name);
+#include "xray_flags.inc"
+#undef XRAY_FLAG
+}
+
+void InitializeFlags() {
+ SetCommonFlagsDefaults();
+ auto *F = flags();
+ F->SetDefaults();
+
+ FlagParser XRayParser;
+ RegisterXRayFlags(&XRayParser, F);
+ RegisterCommonFlags(&XRayParser);
+
+ // Override from command line.
+ XRayParser.ParseString(GetEnv("XRAY_OPTIONS"));
+
+ InitializeCommonFlags();
+
+ if (Verbosity())
+ ReportUnrecognizedFlags();
+
+ if (common_flags()->help) {
+ XRayParser.PrintFlagDescriptions();
+ }
+}
+
+} // namespace __xray
Added: compiler-rt/trunk/lib/xray/xray_flags.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_flags.h?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_flags.h (added)
+++ compiler-rt/trunk/lib/xray/xray_flags.h Wed Jul 20 09:14:50 2016
@@ -0,0 +1,37 @@
+//===-- xray_flags.h -------------------------------------------*- 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 instruementation system.
+//
+// XRay runtime flags.
+//===----------------------------------------------------------------------===//
+
+#ifndef XRAY_FLAGS_H
+#define XRAY_FLAGS_H
+
+#include "sanitizer_common/sanitizer_flag_parser.h"
+
+namespace __xray {
+
+struct Flags {
+#define XRAY_FLAG(Type, Name, DefaultValue, Description) Type Name;
+#include "xray_flags.inc"
+#undef XRAY_FLAG
+
+ void SetDefaults();
+};
+
+extern Flags xray_flags_dont_use_directly;
+inline Flags *flags() { return &xray_flags_dont_use_directly; }
+
+void InitializeFlags();
+
+} // namespace __xray
+
+#endif // XRAY_FLAGS_H
Added: compiler-rt/trunk/lib/xray/xray_flags.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_flags.inc?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_flags.inc (added)
+++ compiler-rt/trunk/lib/xray/xray_flags.inc Wed Jul 20 09:14:50 2016
@@ -0,0 +1,18 @@
+//===-- xray_flags.inc ------------------------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// XRay runtime flags.
+//
+//===----------------------------------------------------------------------===//
+#ifndef XRAY_FLAG
+#error "Define XRAY_FLAG prior to including this file!"
+#endif
+
+XRAY_FLAG(bool, patch_premain, true,
+ "Whether to patch instrumentation points before main.")
Added: compiler-rt/trunk/lib/xray/xray_init.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_init.cc?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_init.cc (added)
+++ compiler-rt/trunk/lib/xray/xray_init.cc Wed Jul 20 09:14:50 2016
@@ -0,0 +1,68 @@
+//===-- xray_init.cc --------------------------------------------*- 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.
+//
+// XRay initialisation logic.
+//===----------------------------------------------------------------------===//
+
+#include <atomic>
+#include <fcntl.h>
+#include <strings.h>
+#include <unistd.h>
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "xray_flags.h"
+#include "xray_interface_internal.h"
+#include "llvm/Support/ELF.h"
+
+extern "C" {
+extern void __xray_init();
+extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak));
+extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak));
+}
+
+using namespace __xray;
+
+// We initialize some global variables that pertain to specific sections of XRay
+// data structures in the binary. We do this for the current process using
+// /proc/curproc/map and make sure that we're able to get it. We signal failure
+// via a global atomic boolean to indicate whether we've initialized properly.
+//
+std::atomic<bool> XRayInitialized{false};
+
+// This should always be updated before XRayInitialized is updated.
+std::atomic<__xray::XRaySledMap> XRayInstrMap{};
+
+// __xray_init() will do the actual loading of the current process' memory map
+// and then proceed to look for the .xray_instr_map section/segment.
+void __xray_init() {
+ InitializeFlags();
+ if (__start_xray_instr_map == nullptr) {
+ Report("XRay instrumentation map missing. Not initializing XRay.\n");
+ return;
+ }
+
+ // Now initialize the XRayInstrMap global struct with the address of the
+ // entries, reinterpreted as an array of XRaySledEntry objects. We use the
+ // virtual pointer we have from the section to provide us the correct
+ // information.
+ __xray::XRaySledMap SledMap{};
+ SledMap.Sleds = __start_xray_instr_map;
+ SledMap.Entries = __stop_xray_instr_map - __start_xray_instr_map;
+ XRayInstrMap.store(SledMap, std::memory_order_release);
+ XRayInitialized.store(true, std::memory_order_release);
+
+ // FIXME: Check the flag/environment before patching.
+ if (flags()->patch_premain)
+ __xray_patch();
+}
+
+__attribute__((section(".preinit_array"),
+ used)) void (*__local_xray_preinit)(void) = __xray_init;
Added: compiler-rt/trunk/lib/xray/xray_interface.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_interface.cc?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_interface.cc (added)
+++ compiler-rt/trunk/lib/xray/xray_interface.cc Wed Jul 20 09:14:50 2016
@@ -0,0 +1,179 @@
+//===-- 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;
+}
Added: compiler-rt/trunk/lib/xray/xray_interface_internal.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_interface_internal.h?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_interface_internal.h (added)
+++ compiler-rt/trunk/lib/xray/xray_interface_internal.h Wed Jul 20 09:14:50 2016
@@ -0,0 +1,40 @@
+//===-- xray_interface_internal.h -------------------------------*- 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. See also include/xray/xray_interface.h.
+//
+//===----------------------------------------------------------------------===//
+#ifndef XRAY_INTERFACE_INTERNAL_H
+#define XRAY_INTERFACE_INTERNAL_H
+
+#include "xray/xray_interface.h"
+#include <cstdint>
+
+extern "C" {
+
+struct XRaySledEntry {
+ uint64_t Address;
+ uint64_t Function;
+ unsigned char Kind;
+ unsigned char AlwaysInstrument;
+ unsigned char Padding[14]; // Need 32 bytes
+};
+}
+
+namespace __xray {
+
+struct XRaySledMap {
+ const XRaySledEntry *Sleds;
+ std::size_t Entries;
+};
+}
+
+#endif
Added: compiler-rt/trunk/lib/xray/xray_trampoline_x86.S
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_trampoline_x86.S?rev=276117&view=auto
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_trampoline_x86.S (added)
+++ compiler-rt/trunk/lib/xray/xray_trampoline_x86.S Wed Jul 20 09:14:50 2016
@@ -0,0 +1,93 @@
+//===-- xray_trampoline_x86.s -----------------------------------*- ASM -*-===//
+//
+// 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.
+//
+// This implements the X86-specific assembler for the trampolines.
+//
+//===----------------------------------------------------------------------===//
+
+ .text
+ .file "xray_trampoline_x86.S"
+ .globl __xray_FunctionEntry
+ .align 16, 0x90
+ .type __xray_FunctionEntry, at function
+
+__xray_FunctionEntry:
+ .cfi_startproc
+ // Save caller provided registers before doing any actual work.
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ subq $72, %rsp
+ movq %rdi, 64(%rsp)
+ movq %rax, 56(%rsp)
+ movq %rdx, 48(%rsp)
+ movq %rsi, 40(%rsp)
+ movq %rcx, 32(%rsp)
+ movq %r8, 24(%rsp)
+ movq %r9, 16(%rsp)
+
+ // de-mangled, that's __xray::XRayPatchedFunction, and we're doing an acquire
+ // load (on x86 is a normal mov instruction).
+ movq _ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+ testq %rax, %rax
+ je .Ltmp0
+
+ // assume that %r10d has the function id.
+ movl %r10d, %edi
+ xor %esi,%esi
+ callq *%rax
+.Ltmp0:
+ // restore the registers
+ movq 64(%rsp), %rdi
+ movq 56(%rsp), %rax
+ movq 48(%rsp), %rdx
+ movq 40(%rsp), %rsi
+ movq 32(%rsp), %rcx
+ movq 24(%rsp), %r8
+ movq 16(%rsp), %r9
+ addq $72, %rsp
+ popq %rbp
+ retq
+.Ltmp1:
+ .size __xray_FunctionEntry, .Ltmp1-__xray_FunctionEntry
+ .cfi_endproc
+
+ .globl __xray_FunctionExit
+ .align 16, 0x90
+ .type __xray_FunctionExit, at function
+__xray_FunctionExit:
+ .cfi_startproc
+ // Save the important registers first. Since we're assuming that this
+ // function is only jumped into, we only preserve the registers for
+ // returning.
+ // FIXME: Figure out whether this is sufficient.
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ subq $24, %rsp
+ .cfi_def_cfa_offset 32
+ movq %rax, 16(%rsp)
+ movq %rdx, 8(%rsp)
+ movq _ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+ testq %rax,%rax
+ je .Ltmp2
+
+ movl %r10d, %edi
+ movl $1, %esi
+ callq *%rax
+.Ltmp2:
+ // Restore the important registers.
+ movq 16(%rsp), %rax
+ movq 8(%rsp), %rdx
+ addq $24, %rsp
+ popq %rbp
+ retq
+.Ltmp3:
+ .size __xray_FunctionExit, .Ltmp3-__xray_FunctionExit
+ .cfi_endproc
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