diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
@@ -9,25 +9,32 @@
 // Information about the process mappings (Solaris-specific parts).
 //===----------------------------------------------------------------------===//
 
-// Before Solaris 11.4, <procfs.h> doesn't work in a largefile environment.
-#undef _FILE_OFFSET_BITS
 #include "sanitizer_platform.h"
 #if SANITIZER_SOLARIS
-#include "sanitizer_common.h"
-#include "sanitizer_procmaps.h"
+#  include <fcntl.h>
+#  include <limits.h>
+#  include <procfs.h>
 
-#include <procfs.h>
-#include <limits.h>
+#  include "sanitizer_common.h"
+#  include "sanitizer_procmaps.h"
 
 namespace __sanitizer {
 
 void ReadProcMaps(ProcSelfMapsBuff *proc_maps) {
-  if (!ReadFileToBuffer("/proc/self/xmap", &proc_maps->data,
-                        &proc_maps->mmaped_size, &proc_maps->len)) {
-    proc_maps->data = nullptr;
-    proc_maps->mmaped_size = 0;
-    proc_maps->len = 0;
-  }
+  uptr fd = internal_open("/proc/self/xmap", O_RDONLY);
+  CHECK_NE(fd, -1);
+  uptr Size = internal_filesize(fd);
+  CHECK_GT(Size, 0);
+
+  // Allow for additional entries by following mmap.
+  size_t MmapedSize = Size * 4 / 3;
+  void *VmMap = MmapOrDie(MmapedSize, "ReadProcMaps()");
+  Size = internal_read(fd, VmMap, MmapedSize);
+  CHECK_NE(Size, -1);
+  internal_close(fd);
+  proc_maps->data = (char *)VmMap;
+  proc_maps->mmaped_size = MmapedSize;
+  proc_maps->len = Size;
 }
 
 bool MemoryMappingLayout::Next(MemoryMappedSegment *segment) {
@@ -49,21 +56,28 @@
     segment->protection |= kProtectionWrite;
   if ((xmapentry->pr_mflags & MA_EXEC) != 0)
     segment->protection |= kProtectionExecute;
+  if ((xmapentry->pr_mflags & MA_SHARED) != 0)
+    segment->protection |= kProtectionShared;
 
   if (segment->filename != NULL && segment->filename_size > 0) {
     char proc_path[PATH_MAX + 1];
 
-    internal_snprintf(proc_path, sizeof(proc_path), "/proc/self/path/%s",
-                      xmapentry->pr_mapname);
-    ssize_t sz = internal_readlink(proc_path, segment->filename,
-                                   segment->filename_size - 1);
-
-    // If readlink failed, the map is anonymous.
-    if (sz == -1) {
+    // Avoid unnecessary readlink on unnamed entires.
+    if (xmapentry->pr_mapname[0] == '\0')
       segment->filename[0] = '\0';
-    } else if ((size_t)sz < segment->filename_size)
-      // readlink doesn't NUL-terminate.
-      segment->filename[sz] = '\0';
+    else {
+      internal_snprintf(proc_path, sizeof(proc_path), "/proc/self/path/%s",
+                        xmapentry->pr_mapname);
+      ssize_t sz = internal_readlink(proc_path, segment->filename,
+                                     segment->filename_size - 1);
+
+      // If readlink failed, the map is anonymous.
+      if (sz == -1)
+        segment->filename[0] = '\0';
+      else if ((size_t)sz < segment->filename_size)
+        // readlink doesn't NUL-terminate.
+        segment->filename[sz] = '\0';
+    }
   }
 
   data_.current += sizeof(prxmap_t);