Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -641,7 +641,7 @@
 endif()
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND XRAY_SUPPORTED_ARCH AND
-    OS_NAME MATCHES "Darwin|Linux|FreeBSD|NetBSD|OpenBSD")
+    OS_NAME MATCHES "Darwin|Linux|FreeBSD|NetBSD|OpenBSD|Fuchsia")
   set(COMPILER_RT_HAS_XRAY TRUE)
 else()
   set(COMPILER_RT_HAS_XRAY FALSE)
Index: lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
===================================================================
--- lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
+++ lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
@@ -31,6 +31,7 @@
 #include "sanitizer_atomic.h"
 #include "sanitizer_common.h"
 #include "sanitizer_internal_defs.h"
+#include "sanitizer_symbolizer_fuchsia.h"
 
 #include <zircon/process.h>
 #include <zircon/sanitizer.h>
@@ -101,7 +102,7 @@
       // uses the `dumpfile` symbolizer markup element to highlight the
       // dump.  See the explanation for this in:
       // https://fuchsia.googlesource.com/zircon/+/master/docs/symbolizer_markup.md
-      Printf("SanitizerCoverage: {{{dumpfile:%s:%s}}} with up to %u PCs\n",
+      Printf("SanitizerCoverage: " FORMAT_DUMPFILE " with up to %u PCs\n",
              kSancovSinkName, vmo_name_, next_index_ - 1);
     }
   }
Index: lib/sanitizer_common/sanitizer_symbolizer_fuchsia.h
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer_fuchsia.h
+++ lib/sanitizer_common/sanitizer_symbolizer_fuchsia.h
@@ -35,6 +35,9 @@
 // One frame in a backtrace (printed on a line by itself).
 constexpr const char *kFormatFrame = "{{{bt:%u:%p}}}";
 
+// Dump trigger element.
+#define FORMAT_DUMPFILE "{{{dumpfile:%s:%s}}}"
+
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_SYMBOLIZER_FUCHSIA_H
Index: lib/xray/xray_allocator.h
===================================================================
--- lib/xray/xray_allocator.h
+++ lib/xray/xray_allocator.h
@@ -19,7 +19,13 @@
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_internal_defs.h"
 #include "sanitizer_common/sanitizer_mutex.h"
+#if SANITIZER_FUCHSIA
+#include <zircon/process.h>
+#include <zircon/syscalls.h>
+#include <zircon/status.h>
+#else
 #include "sanitizer_common/sanitizer_posix.h"
+#endif
 #include "xray_defs.h"
 #include "xray_utils.h"
 #include <cstddef>
@@ -33,6 +39,28 @@
 // mmap'ed memory to back the allocators.
 template <class T> T *allocate() XRAY_NEVER_INSTRUMENT {
   uptr RoundedSize = RoundUpTo(sizeof(T), GetPageSizeCached());
+#if SANITIZER_FUCHSIA
+  zx_handle_t Vmo;
+  zx_status_t Status = _zx_vmo_create(RoundedSize, 0, &Vmo);
+  if (Status != ZX_OK) {
+    if (Verbosity())
+      Report("XRay Profiling: Failed to create VMO of size %zu: %s\n",
+             sizeof(T), _zx_status_get_string(Status));
+    return nullptr;
+  }
+  uintptr_t B;
+  Status =
+    _zx_vmar_map(_zx_vmar_root_self(), ZX_VM_PERM_READ | ZX_VM_PERM_WRITE, 0,
+                 Vmo, 0, sizeof(T), &B);
+  _zx_handle_close(Vmo);
+  if (Status != ZX_OK) {
+    if (Verbosity())
+      Report("XRay Profiling: Failed to map VMAR of size %zu: %s\n",
+             sizeof(T), _zx_status_get_string(Status));
+    return nullptr;
+  }
+  return reinterpret_cast<T *>(B);
+#else
   uptr B = internal_mmap(NULL, RoundedSize, PROT_READ | PROT_WRITE,
                          MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   int ErrNo;
@@ -43,6 +71,7 @@
           RoundedSize, B);
     return nullptr;
   }
+#endif
   return reinterpret_cast<T *>(B);
 }
 
@@ -50,12 +79,38 @@
   if (B == nullptr)
     return;
   uptr RoundedSize = RoundUpTo(sizeof(T), GetPageSizeCached());
+#if SANITIZER_FUCHSIA
+  _zx_vmar_unmap(_zx_vmar_root_self(),
+                 reinterpret_cast<uintptr_t>(B), RoundedSize);
+#else
   internal_munmap(B, RoundedSize);
+#endif
 }
 
 template <class T = unsigned char>
 T *allocateBuffer(size_t S) XRAY_NEVER_INSTRUMENT {
   uptr RoundedSize = RoundUpTo(S * sizeof(T), GetPageSizeCached());
+#if SANITIZER_FUCHSIA
+  zx_handle_t Vmo;
+  zx_status_t Status = _zx_vmo_create(RoundedSize, 0, &Vmo);
+  if (Status != ZX_OK) {
+    if (Verbosity())
+      Report("XRay Profiling: Failed to create VMO of size %zu: %s\n",
+             S, _zx_status_get_string(Status));
+    return nullptr;
+  }
+  uintptr_t B;
+  Status =
+    _zx_vmar_map(_zx_vmar_root_self(), ZX_VM_PERM_READ | ZX_VM_PERM_WRITE, 0,
+                 Vmo, 0, S, &B);
+  _zx_handle_close(Vmo);
+  if (Status != ZX_OK) {
+    if (Verbosity())
+      Report("XRay Profiling: Failed to map VMAR of size %zu: %s\n",
+             S, _zx_status_get_string(Status));
+    return nullptr;
+  }
+#else
   uptr B = internal_mmap(NULL, RoundedSize, PROT_READ | PROT_WRITE,
                          MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   int ErrNo;
@@ -66,6 +121,7 @@
           RoundedSize, B);
     return nullptr;
   }
+#endif
   return reinterpret_cast<T *>(B);
 }
 
@@ -73,7 +129,11 @@
   if (B == nullptr)
     return;
   uptr RoundedSize = RoundUpTo(S * sizeof(T), GetPageSizeCached());
+#if SANITIZER_FUCHSIA
+  _zx_vmar_unmap(_zx_vmar_root_self(), reinterpret_cast<uintptr_t>(B), RoundedSize);
+#else
   internal_munmap(B, RoundedSize);
+#endif
 }
 
 template <class T, class... U>
Index: lib/xray/xray_basic_logging.cc
===================================================================
--- lib/xray/xray_basic_logging.cc
+++ lib/xray/xray_basic_logging.cc
@@ -19,7 +19,9 @@
 #include <fcntl.h>
 #include <pthread.h>
 #include <sys/stat.h>
+#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD || SANITIZER_MAC
 #include <sys/syscall.h>
+#endif
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
Index: lib/xray/xray_buffer_queue.cc
===================================================================
--- lib/xray/xray_buffer_queue.cc
+++ lib/xray/xray_buffer_queue.cc
@@ -16,7 +16,9 @@
 #include "sanitizer_common/sanitizer_atomic.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_libc.h"
+#if !SANITIZER_FUCHSIA
 #include "sanitizer_common/sanitizer_posix.h"
+#endif
 #include "xray_allocator.h"
 #include "xray_defs.h"
 #include <memory>
Index: lib/xray/xray_fdr_logging.cc
===================================================================
--- lib/xray/xray_fdr_logging.cc
+++ lib/xray/xray_fdr_logging.cc
@@ -20,7 +20,6 @@
 #include <limits>
 #include <memory>
 #include <pthread.h>
-#include <sys/syscall.h>
 #include <sys/time.h>
 #include <time.h>
 #include <unistd.h>
Index: lib/xray/xray_interface.cc
===================================================================
--- lib/xray/xray_interface.cc
+++ lib/xray/xray_interface.cc
@@ -22,6 +22,13 @@
 #include <string.h>
 #include <sys/mman.h>
 
+#if SANITIZER_FUCHSIA
+#include <zircon/process.h>
+#include <zircon/sanitizer.h>
+#include <zircon/status.h>
+#include <zircon/syscalls.h>
+#endif
+
 #include "sanitizer_common/sanitizer_addrhashmap.h"
 #include "sanitizer_common/sanitizer_common.h"
 
@@ -92,22 +99,48 @@
 
 public:
   explicit MProtectHelper(void *PageAlignedAddr,
-                          std::size_t MProtectLen) XRAY_NEVER_INSTRUMENT
+                          std::size_t MProtectLen,
+                          std::size_t PageSize) XRAY_NEVER_INSTRUMENT
       : PageAlignedAddr(PageAlignedAddr),
         MProtectLen(MProtectLen),
-        MustCleanup(false) {}
+        MustCleanup(false) {
+#if SANITIZER_FUCHSIA
+    MProtectLen = RoundUpTo(MProtectLen, PageSize);
+#endif
+  }
 
   int MakeWriteable() XRAY_NEVER_INSTRUMENT {
+#if SANITIZER_FUCHSIA
+    auto R = __sanitizer_change_code_protection(
+        reinterpret_cast<uintptr_t>(PageAlignedAddr), MProtectLen, true);
+    if (R != ZX_OK) {
+      Report("XRay: cannot change code protection: %s\n",
+             _zx_status_get_string(R));
+      return -1;
+    }
+    MustCleanup = true;
+    return 0;
+#else
     auto R = mprotect(PageAlignedAddr, MProtectLen,
                       PROT_READ | PROT_WRITE | PROT_EXEC);
     if (R != -1)
       MustCleanup = true;
     return R;
+#endif
   }
 
   ~MProtectHelper() XRAY_NEVER_INSTRUMENT {
     if (MustCleanup) {
+#if SANITIZER_FUCHSIA
+      auto R = __sanitizer_change_code_protection(
+          reinterpret_cast<uintptr_t>(PageAlignedAddr), MProtectLen, false);
+      if (R != ZX_OK) {
+        Report("XRay: cannot change code protection: %s\n",
+               _zx_status_get_string(R));
+      }
+#else
       mprotect(PageAlignedAddr, MProtectLen, PROT_READ | PROT_EXEC);
+#endif
     }
   }
 };
@@ -254,7 +287,7 @@
       reinterpret_cast<void *>(MinSled.Address & ~(PageSize - 1));
   size_t MProtectLen =
       (MaxSled.Address - reinterpret_cast<uptr>(PageAlignedAddr)) + cSledLength;
-  MProtectHelper Protector(PageAlignedAddr, MProtectLen);
+  MProtectHelper Protector(PageAlignedAddr, MProtectLen, PageSize);
   if (Protector.MakeWriteable() == -1) {
     Report("Failed mprotect: %d\n", errno);
     return XRayPatchingStatus::FAILED;
@@ -319,7 +352,7 @@
       reinterpret_cast<void *>(MinSled.Address & ~(PageSize - 1));
   size_t MProtectLen =
       (MaxSled.Address - reinterpret_cast<uptr>(PageAlignedAddr)) + cSledLength;
-  MProtectHelper Protector(PageAlignedAddr, MProtectLen);
+  MProtectHelper Protector(PageAlignedAddr, MProtectLen, PageSize);
   if (Protector.MakeWriteable() == -1) {
     Report("Failed mprotect: %d\n", errno);
     return XRayPatchingStatus::FAILED;
Index: lib/xray/xray_tsc.h
===================================================================
--- lib/xray/xray_tsc.h
+++ lib/xray/xray_tsc.h
@@ -13,10 +13,32 @@
 #ifndef XRAY_EMULATE_TSC_H
 #define XRAY_EMULATE_TSC_H
 
+#include "sanitizer_common/sanitizer_common.h"
+
 namespace __xray {
 static constexpr uint64_t NanosecondsPerSecond = 1000ULL * 1000 * 1000;
 }
 
+#if SANITIZER_FUCHSIA
+#include <zircon/syscalls.h>
+
+namespace __xray {
+
+inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
+
+ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
+  CPU = 0;
+  return _zx_ticks_get();
+}
+
+inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
+  return _zx_ticks_per_second();
+}
+
+} // namespace __xray
+
+#else // SANITIZER_FUCHSIA
+
 #if defined(__x86_64__)
 #include "xray_x86_64.inc"
 #elif defined(__powerpc64__)
@@ -64,5 +86,6 @@
 #else
 #error Target architecture is not supported.
 #endif // CPU architecture
+#endif // SANITIZER_FUCHSIA
 
 #endif // XRAY_EMULATE_TSC_H
Index: lib/xray/xray_utils.h
===================================================================
--- lib/xray/xray_utils.h
+++ lib/xray/xray_utils.h
@@ -20,30 +20,41 @@
 #include <sys/types.h>
 #include <utility>
 
+#include "sanitizer_common/sanitizer_common.h"
+#if SANITIZER_FUCHSIA
+#include <zircon/types.h>
+#endif
+
 namespace __xray {
 
 class LogWriter {
 public:
+#if SANITIZER_FUCHSIA
+ LogWriter(zx_handle_t Vmo) : Vmo(Vmo) {}
+#else
   explicit LogWriter(int Fd) : Fd(Fd) {}
-  ~LogWriter();
+#endif
+ ~LogWriter();
 
-  // Write a character range into a log.
-  void WriteAll(const char *Begin, const char *End);
+ // Write a character range into a log.
+ void WriteAll(const char *Begin, const char *End);
 
-  void Flush();
+ void Flush();
 
-  // Returns a new log instance initialized using the flag-provided values.
-  static LogWriter *Open();
-  // Closes and deallocates the log instance.
-  static void Close(LogWriter *LogWriter);
+ // Returns a new log instance initialized using the flag-provided values.
+ static LogWriter *Open();
+ // Closes and deallocates the log instance.
+ static void Close(LogWriter *LogWriter);
 
 private:
-  int Fd = -1;
+#if SANITIZER_FUCHSIA
+ zx_handle_t Vmo = ZX_HANDLE_INVALID;
+ uint64_t Offset = 0;
+#else
+ int Fd = -1;
+#endif
 };
 
-// Default implementation of the reporting interface for sanitizer errors.
-void printToStdErr(const char *Buffer);
-
 constexpr size_t gcd(size_t a, size_t b) {
   return (b == 0) ? a : gcd(b, a % b);
 }
Index: lib/xray/xray_utils.cc
===================================================================
--- lib/xray/xray_utils.cc
+++ lib/xray/xray_utils.cc
@@ -27,12 +27,108 @@
 #include <unistd.h>
 #include <utility>
 
+#if SANITIZER_FUCHSIA
+#include "sanitizer_common/sanitizer_symbolizer_fuchsia.h"
+
+#include <inttypes.h>
+#include <zircon/process.h>
+#include <zircon/sanitizer.h>
+#include <zircon/status.h>
+#include <zircon/syscalls.h>
+#endif
+
 namespace __xray {
 
-void printToStdErr(const char *Buffer) XRAY_NEVER_INSTRUMENT {
-  fprintf(stderr, "%s", Buffer);
+#if SANITIZER_FUCHSIA
+constexpr const char* ProfileSinkName = "llvm-xray";
+
+LogWriter::~LogWriter() {
+  _zx_handle_close(Vmo);
+}
+
+void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
+  if (Begin == End)
+    return;
+  auto TotalBytes = std::distance(Begin, End);
+
+  const size_t PageSize = flags()->xray_page_size_override > 0
+                              ? flags()->xray_page_size_override
+                              : GetPageSizeCached();
+  if (RoundUpTo(Offset, PageSize) != RoundUpTo(Offset + TotalBytes, PageSize)) {
+    // Resize the VMO to ensure there's sufficient space for the data.
+    zx_status_t Status = _zx_vmo_set_size(Vmo, Offset + TotalBytes);
+    if (Status != ZX_OK) {
+      Report("Failed to resize VMO: %s\n", _zx_status_get_string(Status));
+      return;
+    }
+  }
+
+  // Write the data into VMO.
+  zx_status_t Status = _zx_vmo_write(Vmo, Begin, Offset, TotalBytes);
+  if (Status != ZX_OK) {
+    Report("Failed to write: %s\n", _zx_status_get_string(Status));
+    return;
+  }
+  Offset += TotalBytes;
+}
+
+void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
+  // Nothing to do here since WriteAll writes directly into the VMO.
 }
 
+LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
+  // Create VMO to hold the profile data.
+  zx_handle_t Vmo;
+  zx_status_t Status = _zx_vmo_create(0, 0, &Vmo);
+  if (Status != ZX_OK) {
+    Report("XRay: cannot create VMO: %s\n", _zx_status_get_string(Status));
+    return nullptr;
+  }
+
+  // Get the KOID of the current process to use in the VMO name.
+  zx_info_handle_basic_t Info;
+  Status = _zx_object_get_info(_zx_process_self(), ZX_INFO_HANDLE_BASIC, &Info,
+                               sizeof(Info), NULL, NULL);
+  if (Status != ZX_OK) {
+    Report("XRay: cannot get basic info about current process handle: %s\n",
+           _zx_status_get_string(Status));
+    return nullptr;
+  }
+
+  // Give the VMO a name including our process KOID so it's easy to spot.
+  char VmoName[ZX_MAX_NAME_LEN];
+  internal_snprintf(VmoName, sizeof(VmoName), "%s.%zu", ProfileSinkName,
+                    Info.koid);
+  _zx_object_set_property(Vmo, ZX_PROP_NAME, VmoName, strlen(VmoName));
+
+  // Duplicate the handle since __sanitizer_publish_data consumes it and
+  // LogWriter needs to hold onto it.
+  zx_handle_t Handle;
+  Status =_zx_handle_duplicate(Vmo, ZX_RIGHT_SAME_RIGHTS, &Handle);
+  if (Status != ZX_OK) {
+    Report("XRay: cannot duplicate VMO handle: %s\n",
+           _zx_status_get_string(Status));
+    return nullptr;
+  }
+
+  // Publish the VMO that receives the logging. Note the VMO's contents can
+  // grow and change after publication. The contents won't be read out until
+  // after the process exits.
+  __sanitizer_publish_data(ProfileSinkName, Handle);
+
+  // Use the dumpfile symbolizer markup element to write the name of the VMO.
+  Report("XRay: " FORMAT_DUMPFILE "\n", ProfileSinkName, VmoName);
+
+  LogWriter *LW = reinterpret_cast<LogWriter *>(InternalAlloc(sizeof(LogWriter)));
+  new (LW) LogWriter(Vmo);
+  return LW;
+}
+
+void LogWriter::Close(LogWriter *LW) {
+  LW->~LogWriter();
+  InternalFree(LW);
+}
+#else // SANITIZER_FUCHSIA
 LogWriter::~LogWriter() {
   internal_close(Fd);
 }
@@ -95,5 +191,6 @@
   LW->~LogWriter();
   deallocate(LW);
 }
+#endif // SANITIZER_FUCHSIA
 
 } // namespace __xray
Index: lib/xray/xray_x86_64.cc
===================================================================
--- lib/xray/xray_x86_64.cc
+++ lib/xray/xray_x86_64.cc
@@ -1,6 +1,8 @@
 #include "cpuid.h"
 #include "sanitizer_common/sanitizer_common.h"
+#if !SANITIZER_FUCHSIA
 #include "sanitizer_common/sanitizer_posix.h"
+#endif
 #include "xray_defs.h"
 #include "xray_interface_internal.h"
 
@@ -11,6 +13,8 @@
 #include <machine/cpu.h>
 #endif
 #include <sys/sysctl.h>
+#elif SANITIZER_FUCHSIA
+#include <zircon/syscalls.h>
 #endif
 
 #include <atomic>
@@ -104,7 +108,7 @@
 
     return 0;
 }
-#else
+#elif !SANITIZER_FUCHSIA
 uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
     /* Not supported */
     return 0;
@@ -321,6 +325,7 @@
   return false;
 }
 
+#if !SANITIZER_FUCHSIA
 // We determine whether the CPU we're running on has the correct features we
 // need. In x86_64 this will be rdtscp support.
 bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT {
@@ -343,5 +348,6 @@
   }
   return true;
 }
+#endif
 
 } // namespace __xray