diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -135,6 +135,15 @@
 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
                       uptr min_shadow_base_alignment, uptr &high_mem_end);
 
+// Let S = max(shadow_size, num_aliases * alias_size, ring_buffer_size).
+// Reserves 2*S bytes of address space to the right of the returned address and
+// ring_buffer_size bytes to the left.  The returned address is aligned to 2*S.
+// Also creates num_aliases regions of accessible memory starting at offset S
+// from the returned address.  Each region has size alias_size and is backed by
+// the same physical memory.
+uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
+                                uptr num_aliases, uptr ring_buffer_size);
+
 // Reserve memory range [beg, end]. If madvise_shadow is true then apply
 // madvise (e.g. hugepages, core dumping) requested by options.
 void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name,
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
@@ -36,6 +36,7 @@
 #include <link.h>
 #include <pthread.h>
 #include <signal.h>
+#include <sys/mman.h>
 #include <sys/resource.h>
 #include <syslog.h>
 
@@ -911,6 +912,60 @@
   return shadow_start;
 }
 
+static uptr MmapSharedNoReserve(uptr addr, uptr size) {
+  return internal_mmap(
+      reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE,
+      MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
+}
+
+static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
+                              uptr alias_size) {
+  return reinterpret_cast<uptr>(mremap(
+      reinterpret_cast<void *>(base_addr), 0, alias_size,
+      MREMAP_MAYMOVE | MREMAP_FIXED, reinterpret_cast<void *>(alias_addr)));
+}
+
+static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) {
+  uptr total_size = alias_size * num_aliases;
+  uptr mapped = MmapSharedNoReserve(start_addr, total_size);
+  CHECK_EQ(mapped, start_addr);
+
+  for (uptr i = 1; i < num_aliases; ++i) {
+    uptr alias_addr = start_addr + i * alias_size;
+    CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr);
+  }
+}
+
+uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
+                                uptr num_aliases, uptr ring_buffer_size) {
+  CHECK_EQ(alias_size & (alias_size - 1), 0);
+  CHECK_EQ(num_aliases & (num_aliases - 1), 0);
+  CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0);
+
+  const uptr granularity = GetMmapGranularity();
+  shadow_size = RoundUpTo(shadow_size, granularity);
+  CHECK_EQ(shadow_size & (shadow_size - 1), 0);
+
+  const uptr alias_region_size = alias_size * num_aliases;
+  const uptr alignment =
+      2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size);
+  const uptr left_padding = ring_buffer_size;
+
+  const uptr right_size = alignment;
+  const uptr map_size = left_padding + 2 * alignment;
+
+  const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size));
+  CHECK_NE(map_start, ~static_cast<uptr>(0));
+  const uptr right_start = RoundUpTo(map_start + left_padding, alignment);
+
+  UnmapFromTo(map_start, right_start - left_padding);
+  UnmapFromTo(right_start + right_size, map_start + map_size);
+
+  CreateAliases(right_start + right_size / 2, alias_size, num_aliases);
+
+  return right_start;
+}
+
 void InitializePlatformCommonFlags(CommonFlags *cf) {
 #if SANITIZER_ANDROID
   if (&__libc_get_static_tls_bounds == nullptr)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
@@ -1252,6 +1252,12 @@
   return shadow_start;
 }
 
+uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
+                                uptr num_aliases, uptr ring_buffer_size) {
+  CHECK(false && "HWASan aliasing is unimplemented on Mac");
+  return 0;
+}
+
 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
                               uptr *largest_gap_found,
                               uptr *max_occupied_addr) {
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_win.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_win.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_win.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_win.cpp
@@ -390,6 +390,12 @@
   return 0;
 }
 
+uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
+                                uptr num_aliases, uptr ring_buffer_size) {
+  CHECK(false && "HWASan aliasing is unimplemented on Windows");
+  return 0;
+}
+
 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
   MEMORY_BASIC_INFORMATION mbi;
   CHECK(VirtualQuery((void *)range_start, &mbi, sizeof(mbi)));