Index: compiler-rt/cmake/config-ix.cmake
===================================================================
--- compiler-rt/cmake/config-ix.cmake
+++ compiler-rt/cmake/config-ix.cmake
@@ -211,7 +211,11 @@
 set(ALL_CFI_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${MIPS64})
 set(ALL_ESAN_SUPPORTED_ARCH ${X86_64} ${MIPS64})
 set(ALL_SCUDO_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${MIPS32} ${MIPS64})
+if(APPLE)
+set(ALL_XRAY_SUPPORTED_ARCH ${X86_64})
+else()
 set(ALL_XRAY_SUPPORTED_ARCH ${X86_64} ${ARM32} ${ARM64} ${MIPS32} ${MIPS64} powerpc64le)
+endif()
 
 if(APPLE)
   include(CompilerRTDarwinUtils)
@@ -256,6 +260,7 @@
   set(SANITIZER_COMMON_SUPPORTED_OS osx)
   set(PROFILE_SUPPORTED_OS osx)
   set(TSAN_SUPPORTED_OS osx)
+  set(XRAY_SUPPORTED_OS osx)
   if(NOT SANITIZER_MIN_OSX_VERSION)
     string(REGEX MATCH "-mmacosx-version-min=([.0-9]+)"
            MACOSX_VERSION_MIN_FLAG "${CMAKE_CXX_FLAGS}")
@@ -412,12 +417,12 @@
   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)
   list_intersect(FUZZER_SUPPORTED_ARCH
     ALL_FUZZER_SUPPORTED_ARCH
     ALL_SANITIZER_COMMON_SUPPORTED_ARCH)
+  list_intersect(XRAY_SUPPORTED_ARCH
+    ALL_XRAY_SUPPORTED_ARCH
+    SANITIZER_COMMON_SUPPORTED_ARCH)
 
 else()
   # Architectures supported by compiler-rt libraries.
@@ -580,7 +585,7 @@
 endif()
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND XRAY_SUPPORTED_ARCH AND
-    OS_NAME MATCHES "Linux")
+    OS_NAME MATCHES "Darwin|Linux")
   set(COMPILER_RT_HAS_XRAY TRUE)
 else()
   set(COMPILER_RT_HAS_XRAY FALSE)
Index: compiler-rt/lib/xray/CMakeLists.txt
===================================================================
--- compiler-rt/lib/xray/CMakeLists.txt
+++ compiler-rt/lib/xray/CMakeLists.txt
@@ -65,19 +65,53 @@
 append_list_if(
   COMPILER_RT_BUILD_XRAY_NO_PREINIT XRAY_NO_PREINIT XRAY_COMMON_DEFINITIONS)
 
-add_compiler_rt_object_libraries(RTXray
-  ARCHS ${XRAY_SUPPORTED_ARCH}
-  SOURCES ${XRAY_SOURCES} CFLAGS ${XRAY_CFLAGS}
-  DEFS ${XRAY_COMMON_DEFINITIONS})
-
 add_compiler_rt_component(xray)
 
 set(XRAY_COMMON_RUNTIME_OBJECT_LIBS
+    RTXray
     RTSanitizerCommon
     RTSanitizerCommonLibc)
 
+if (APPLE)
+  set(XRAY_LINK_LIBS ${SANITIZER_COMMON_LINK_LIBS})
+  set(XRAY_ASM_SOURCES xray_trampoline_x86_64.S)
+
+  if (${CMAKE_GENERATOR} STREQUAL "Xcode")
+    enable_language(ASM)
+  else()
+    set_source_files_properties(${XRAY_ASM_SOURCES} PROPERTIES LANGUAGE C)
+  endif()
+
+  add_weak_symbols("sanitizer_common" WEAK_SYMBOL_LINK_FLAGS)
+  add_weak_symbols("xray" WEAK_SYMBOL_LINK_FLAGS)
+
+  add_compiler_rt_object_libraries(RTXray
+    OS ${XRAY_SUPPORTED_OS}
+    ARCHS ${XRAY_SUPPORTED_ARCH}
+    SOURCES ${x86_64_SOURCES}
+    CFLAGS ${XRAY_CFLAGS}
+    DEFS ${XRAY_COMMON_DEFINITIONS})
+
+  # We only support running on osx for now.
+  add_compiler_rt_runtime(clang_rt.xray
+    STATIC
+    OS ${XRAY_SUPPORTED_OS}
+    ARCHS ${XRAY_SUPPORTED_ARCH}
+    OBJECT_LIBS RTXray
+                RTSanitizerCommon
+                RTSanitizerCommonLibc
+    CFLAGS ${XRAY_CFLAGS}
+    DEFS ${XRAY_COMMON_DEFINITIONS}
+    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_LIBS ${XRAY_LINK_LIBS}
+    PARENT_TARGET xray)
+else()
 foreach(arch ${XRAY_SUPPORTED_ARCH})
   if(CAN_TARGET_${arch})
+    add_compiler_rt_object_libraries(RTXray
+      ARCHS ${XRAY_SUPPORTED_ARCH}
+      SOURCES ${XRAY_SOURCES} CFLAGS ${XRAY_CFLAGS}
+      DEFS ${XRAY_COMMON_DEFINITIONS})
     add_compiler_rt_runtime(clang_rt.xray
      STATIC
      ARCHS ${arch}
@@ -88,6 +122,7 @@
      PARENT_TARGET xray)
   endif()
 endforeach()
+endif()
 
 if(COMPILER_RT_INCLUDE_TESTS)
   add_subdirectory(tests)
Index: compiler-rt/lib/xray/weak_symbols.txt
===================================================================
--- /dev/null
+++ compiler-rt/lib/xray/weak_symbols.txt
@@ -0,0 +1,4 @@
+___start_xray_fn_idx
+___start_xray_instr_map
+___stop_xray_fn_idx
+___stop_xray_instr_map
Index: compiler-rt/lib/xray/xray_fdr_logging.cc
===================================================================
--- compiler-rt/lib/xray/xray_fdr_logging.cc
+++ compiler-rt/lib/xray/xray_fdr_logging.cc
@@ -70,15 +70,9 @@
     return XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
   }
 
-  // We wait a number of microseconds to allow threads to see that we've
+  // We wait a number of milliseconds to allow threads to see that we've
   // finalised before attempting to flush the log.
-  struct timespec TS;
-  TS.tv_sec = flags()->xray_fdr_log_grace_period_us / 1000000;
-  TS.tv_nsec = (flags()->xray_fdr_log_grace_period_us % 1000000) * 1000;
-  struct timespec Rem;
-  while (clock_nanosleep(CLOCK_REALTIME, 0, &TS, &Rem) &&
-         (Rem.tv_sec != 0 || Rem.tv_nsec != 0))
-    TS = Rem;
+  __sanitizer::SleepForMillis(flags()->xray_fdr_log_grace_period_ms);
 
   // We write out the file in the following format:
   //
@@ -374,9 +368,7 @@
   using namespace __xray;
   if (flags()->xray_fdr_log) {
     XRayLogImpl Impl{
-        fdrLoggingInit,
-        fdrLoggingFinalize,
-        fdrLoggingHandleArg0,
+        fdrLoggingInit, fdrLoggingFinalize, fdrLoggingHandleArg0,
         fdrLoggingFlush,
     };
     __xray_set_log_impl(Impl);
Index: compiler-rt/lib/xray/xray_flags.inc
===================================================================
--- compiler-rt/lib/xray/xray_flags.inc
+++ compiler-rt/lib/xray/xray_flags.inc
@@ -37,7 +37,9 @@
 XRAY_FLAG(int, xray_fdr_log_func_duration_threshold_us, 5,
           "FDR logging will try to skip functions that execute for fewer "
           "microseconds than this threshold.")
-XRAY_FLAG(int, xray_fdr_log_grace_period_us, 100000,
+XRAY_FLAG(int, xray_fdr_log_grace_period_us, 0,
+          "DEPRECATED: use xray_fdr_log_grace_period_ms instead.")
+XRAY_FLAG(int, xray_fdr_log_grace_period_ms, 100,
           "FDR logging will wait this much time in microseconds before "
           "actually flushing the log; this gives a chance for threads to "
           "notice that the log has been finalized and clean up.")
Index: compiler-rt/lib/xray/xray_init.cc
===================================================================
--- compiler-rt/lib/xray/xray_init.cc
+++ compiler-rt/lib/xray/xray_init.cc
@@ -88,7 +88,15 @@
 #endif
 }
 
-#ifndef XRAY_NO_PREINIT
+#if !defined(XRAY_NO_PREINIT) && SANITIZER_CAN_USE_PREINIT_ARRAY
+// Only add the preinit array initialization if the sanitizers can.
 __attribute__((section(".preinit_array"),
                used)) void (*__local_xray_preinit)(void) = __xray_init;
+#else
+// If we cannot use the .preinit_array section, we should instead use dynamic
+// initialisation.
+static bool UNUSED __local_xray_dyninit = [] {
+  __xray_init();
+  return true;
+}();
 #endif
Index: compiler-rt/lib/xray/xray_trampoline_x86_64.S
===================================================================
--- compiler-rt/lib/xray/xray_trampoline_x86_64.S
+++ compiler-rt/lib/xray/xray_trampoline_x86_64.S
@@ -14,10 +14,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "../builtins/assembly.h"
+#include "../sanitizer_common/sanitizer_asm.h"
+
+
 
 .macro SAVE_REGISTERS
 	subq $192, %rsp
-	.cfi_def_cfa_offset 200
+	CFI_DEF_CFA_OFFSET(200)
 	// At this point, the stack pointer should be aligned to an 8-byte boundary,
 	// because any call instructions that come after this will add another 8
 	// bytes and therefore align it to 16-bytes.
@@ -57,7 +60,7 @@
 	movq	8(%rsp), %r8
 	movq	0(%rsp), %r9
 	addq	$192, %rsp
-	.cfi_def_cfa_offset 8
+	CFI_DEF_CFA_OFFSET(8)
 .endm
 
 .macro ALIGNED_CALL_RAX
@@ -75,21 +78,25 @@
 .endm
 
 	.text
+#if !defined(__APPLE__)
+	.section .text
+#else
+	.section __TEXT,__text
+#endif
 	.file "xray_trampoline_x86.S"
 
 //===----------------------------------------------------------------------===//
 
-	.globl __xray_FunctionEntry
+	.globl ASM_TSAN_SYMBOL(__xray_FunctionEntry)
 	.align 16, 0x90
-	.type __xray_FunctionEntry,@function
-
-__xray_FunctionEntry:
-	.cfi_startproc
+	ASM_TYPE_FUNCTION(__xray_FunctionEntry)
+ASM_TSAN_SYMBOL(__xray_FunctionEntry):
+	CFI_STARTPROC
 	SAVE_REGISTERS
 
 	// This load has to be atomic, it's concurrent with __xray_patch().
 	// On x86/amd64, a simple (type-aligned) MOV instruction is enough.
-	movq	_ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+	movq	ASM_TSAN_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)(%rip), %rax
 	testq	%rax, %rax
 	je	.Ltmp0
 
@@ -101,28 +108,27 @@
 .Ltmp0:
 	RESTORE_REGISTERS
 	retq
-.Ltmp1:
-	.size __xray_FunctionEntry, .Ltmp1-__xray_FunctionEntry
-	.cfi_endproc
+	ASM_SIZE(__xray_FunctionEntry)
+	CFI_ENDPROC
 
 //===----------------------------------------------------------------------===//
 
-	.globl __xray_FunctionExit
+	.globl ASM_TSAN_SYMBOL(__xray_FunctionExit)
 	.align 16, 0x90
-	.type __xray_FunctionExit,@function
-__xray_FunctionExit:
-	.cfi_startproc
+	ASM_TYPE_FUNCTION(__xray_FunctionExit)
+ASM_TSAN_SYMBOL(__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.
 	subq	$56, %rsp
-	.cfi_def_cfa_offset 64
+	CFI_DEF_CFA_OFFSET(64)
 	movq  %rbp, 48(%rsp)
 	movupd	%xmm0, 32(%rsp)
 	movupd	%xmm1, 16(%rsp)
 	movq	%rax, 8(%rsp)
 	movq	%rdx, 0(%rsp)
-	movq	_ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+	movq	ASM_TSAN_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)(%rip), %rax
 	testq %rax,%rax
 	je	.Ltmp2
 
@@ -138,22 +144,21 @@
 	movq	8(%rsp), %rax
 	movq	0(%rsp), %rdx
 	addq	$56, %rsp
-	.cfi_def_cfa_offset 8
+	CFI_DEF_CFA_OFFSET(8)
 	retq
-.Ltmp3:
-	.size __xray_FunctionExit, .Ltmp3-__xray_FunctionExit
-	.cfi_endproc
+	ASM_SIZE(__xray_FunctionExit)
+	CFI_ENDPROC
 
 //===----------------------------------------------------------------------===//
 
-	.global __xray_FunctionTailExit
+	.globl ASM_TSAN_SYMBOL(__xray_FunctionTailExit)
 	.align 16, 0x90
-	.type __xray_FunctionTailExit,@function
-__xray_FunctionTailExit:
-	.cfi_startproc
+	ASM_TYPE_FUNCTION(__xray_FunctionTailExit)
+ASM_TSAN_SYMBOL(__xray_FunctionTailExit):
+	CFI_STARTPROC
 	SAVE_REGISTERS
 
-	movq	_ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+	movq	ASM_TSAN_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)(%rip), %rax
 	testq %rax,%rax
 	je	.Ltmp4
 
@@ -165,26 +170,25 @@
 .Ltmp4:
 	RESTORE_REGISTERS
 	retq
-.Ltmp5:
-	.size __xray_FunctionTailExit, .Ltmp5-__xray_FunctionTailExit
-	.cfi_endproc
+	ASM_SIZE(__xray_FunctionTailExit)
+	CFI_ENDPROC
 
 //===----------------------------------------------------------------------===//
 
-	.globl __xray_ArgLoggerEntry
+	.globl ASM_TSAN_SYMBOL(__xray_ArgLoggerEntry)
 	.align 16, 0x90
-	.type __xray_ArgLoggerEntry,@function
-__xray_ArgLoggerEntry:
-	.cfi_startproc
+	ASM_TYPE_FUNCTION(__xray_ArgLoggerEntry)
+ASM_TSAN_SYMBOL(__xray_ArgLoggerEntry):
+	CFI_STARTPROC
 	SAVE_REGISTERS
 
 	// Again, these function pointer loads must be atomic; MOV is fine.
-	movq	_ZN6__xray13XRayArgLoggerE(%rip), %rax
+	movq	ASM_TSAN_SYMBOL(_ZN6__xray13XRayArgLoggerE)(%rip), %rax
 	testq	%rax, %rax
 	jne	.Larg1entryLog
 
 	// If [arg1 logging handler] not set, defer to no-arg logging.
-	movq	_ZN6__xray19XRayPatchedFunctionE(%rip), %rax
+	movq	ASM_TSAN_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)(%rip), %rax
 	testq	%rax, %rax
 	je	.Larg1entryFail
 
@@ -203,24 +207,22 @@
 .Larg1entryFail:
 	RESTORE_REGISTERS
 	retq
-
-.Larg1entryEnd:
-	.size __xray_ArgLoggerEntry, .Larg1entryEnd-__xray_ArgLoggerEntry
-	.cfi_endproc
+	ASM_SIZE(__xray_ArgLoggerEntry)
+	CFI_ENDPROC
 
 //===----------------------------------------------------------------------===//
 
-	.global __xray_CustomEvent
+	.global ASM_TSAN_SYMBOL(__xray_CustomEvent)
 	.align 16, 0x90
-	.type __xray_CustomEvent,@function
-__xray_CustomEvent:
-  .cfi_startproc
+	ASM_TYPE_FUNCTION(__xray_CustomEvent)
+ASM_TSAN_SYMBOL(__xray_CustomEvent):
+	CFI_STARTPROC
 	SAVE_REGISTERS
 
 	// We take two arguments to this trampoline, which should be in rdi	and rsi
 	// already. We also make sure that we stash %rax because we use that register
 	// to call the logging handler.
-	movq _ZN6__xray22XRayPatchedCustomEventE(%rip), %rax
+	movq ASM_TSAN_SYMBOL(_ZN6__xray22XRayPatchedCustomEventE)(%rip), %rax
 	testq %rax,%rax
 	je .LcustomEventCleanup
 
@@ -229,9 +231,7 @@
 .LcustomEventCleanup:
 	RESTORE_REGISTERS
 	retq
-
-.Ltmp8:
-	.size __xray_CustomEvent, .Ltmp8-__xray_CustomEvent
-	.cfi_endproc
+	ASM_SIZE(__xray_CustomEvent)
+	CFI_ENDPROC
 
 NO_EXEC_STACK_DIRECTIVE