diff --git a/compiler-rt/include/sanitizer/msan_interface.h b/compiler-rt/include/sanitizer/msan_interface.h
index de5fc96dfa80..badb33472224 100644
--- a/compiler-rt/include/sanitizer/msan_interface.h
+++ b/compiler-rt/include/sanitizer/msan_interface.h
@@ -78,6 +78,10 @@ extern "C" {
      format. */
   void __msan_print_shadow(const volatile void *x, size_t size);
 
+  /* Print shadow for the memory range to stderr in a minimalistic
+     human-readable format. */
+  void __msan_dump_shadow(const volatile void *x, size_t size);
+
   /* Returns true if running under a dynamic tool (DynamoRio-based). */
   int  __msan_has_dynamic_component();
 
diff --git a/compiler-rt/lib/msan/msan.cc b/compiler-rt/lib/msan/msan.cc
index 8bf7c48acc7a..1df4fb8df7fd 100644
--- a/compiler-rt/lib/msan/msan.cc
+++ b/compiler-rt/lib/msan/msan.cc
@@ -383,18 +383,21 @@ void __msan_print_shadow(const void *x, uptr size) {
     Printf("Not a valid application address: %p\n", x);
     return;
   }
+
+  DescribeMemoryRange(x, size);
+}
+
+void __msan_dump_shadow(const void *x, uptr size) {
+  if (!MEM_IS_APP(x)) {
+    Printf("Not a valid application address: %p\n", x);
+    return;
+  }
+
   unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x);
-  u32 *o = (u32*)MEM_TO_ORIGIN(x);
   for (uptr i = 0; i < size; i++) {
     Printf("%x%x ", s[i] >> 4, s[i] & 0xf);
   }
   Printf("\n");
-  if (__msan_get_track_origins()) {
-    for (uptr i = 0; i < size / 4; i++) {
-      Printf(" o: %x ", o[i]);
-    }
-    Printf("\n");
-  }
 }
 
 sptr __msan_test_shadow(const void *x, uptr size) {
diff --git a/compiler-rt/lib/msan/msan.h b/compiler-rt/lib/msan/msan.h
index 7e16b324ea78..74fd76ed0c21 100644
--- a/compiler-rt/lib/msan/msan.h
+++ b/compiler-rt/lib/msan/msan.h
@@ -83,6 +83,7 @@ void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp,
 void ReportUMR(StackTrace *stack, u32 origin);
 void ReportExpectedUMRNotFound(StackTrace *stack);
 void ReportAtExitStatistics();
+void DescribeMemoryRange(const void *x, uptr size);
 
 // Unpoison first n function arguments.
 void UnpoisonParam(uptr n);
diff --git a/compiler-rt/lib/msan/msan_interface_internal.h b/compiler-rt/lib/msan/msan_interface_internal.h
index a5fc3a43b779..955288dc9b47 100644
--- a/compiler-rt/lib/msan/msan_interface_internal.h
+++ b/compiler-rt/lib/msan/msan_interface_internal.h
@@ -118,6 +118,8 @@ void __msan_set_expect_umr(int expect_umr);
 SANITIZER_INTERFACE_ATTRIBUTE
 void __msan_print_shadow(const void *x, uptr size);
 SANITIZER_INTERFACE_ATTRIBUTE
+void __msan_dump_shadow(const void *x, uptr size);
+SANITIZER_INTERFACE_ATTRIBUTE
 int  __msan_has_dynamic_component();
 
 // Returns x such that %fs:x is the first byte of __msan_retval_tls.
diff --git a/compiler-rt/lib/msan/msan_report.cc b/compiler-rt/lib/msan/msan_report.cc
index 7e709f879995..12bac2e8c064 100644
--- a/compiler-rt/lib/msan/msan_report.cc
+++ b/compiler-rt/lib/msan/msan_report.cc
@@ -124,4 +124,115 @@ void ReportAtExitStatistics() {
   Printf("Stack depot mapped bytes: %zu\n", stack_depot_stats->mapped);
 }
 
+class OriginSet {
+ public:
+  OriginSet() : next_id_(0) {}
+  int insert(u32 o) {
+    // Scan from the end for better locality.
+    for (int i = next_id_ - 1; i >= 0; --i)
+      if (origins_[i] == o) return i;
+    if (next_id_ == kMaxSize_) return OVERFLOW;
+    int id = next_id_++;
+    origins_[id] = o;
+    return id;
+  }
+  int size() { return next_id_; }
+  u32 get(int id) { return origins_[id]; }
+  static char asChar(int id) {
+    switch (id) {
+      case MISSING:
+        return '.';
+      case OVERFLOW:
+        return '*';
+      default:
+        return 'A' + id;
+    }
+  }
+  static const int OVERFLOW = -1;
+  static const int MISSING = -2;
+
+ private:
+  static const int kMaxSize_ = 'Z' - 'A' + 1;
+  u32 origins_[kMaxSize_];
+  int next_id_;
+};
+
+void DescribeMemoryRange(const void *x, uptr size) {
+  // Real limits.
+  uptr start = MEM_TO_SHADOW(x);
+  uptr end = start + size;
+  // Scan limits: align start down to 4; align size up to 16.
+  uptr s = start & ~3UL;
+  size = end - s;
+  size = (size + 15) & ~15UL;
+  uptr e = s + size;
+
+  // Single letter names to origin id mapping.
+  OriginSet origin_set;
+
+  uptr pos = 0;  // Offset from aligned start.
+  bool with_origins = __msan_get_track_origins();
+  // True if there is at least 1 poisoned bit in the last 4-byte group.
+  bool last_quad_poisoned;
+  int origin_ids[4];  // Single letter origin ids for the current line.
+
+  Decorator d;
+  Printf("%s", d.Warning());
+  Printf("Shadow map of [%p, %p), %zu bytes:\n", start, end, end - start);
+  Printf("%s", d.End());
+  while (s < e) {
+    // Line start.
+    if (pos % 16 == 0) {
+      for (int i = 0; i < 4; ++i) origin_ids[i] = -1;
+      Printf("%p:", s);
+    }
+    // Group start.
+    if (pos % 4 == 0) {
+      Printf(" ");
+      last_quad_poisoned = false;
+    }
+    // Print shadow byte.
+    if (s < start || s >= end) {
+      Printf("..");
+    } else {
+      unsigned char v = *(unsigned char *)s;
+      if (v) last_quad_poisoned = true;
+      Printf("%02x", v);
+    }
+    // Group end.
+    if (pos % 4 == 3 && with_origins) {
+      int id = OriginSet::MISSING;
+      if (last_quad_poisoned) {
+        u32 o = *(u32 *)SHADOW_TO_ORIGIN(s - 3);
+        id = origin_set.insert(o);
+      }
+      origin_ids[(pos % 16) / 4] = id;
+    }
+    // Line end.
+    if (pos % 16 == 15) {
+      if (with_origins) {
+        Printf("  |");
+        for (int i = 0; i < 4; ++i) {
+          char c = OriginSet::asChar(origin_ids[i]);
+          Printf("%c", c);
+          if (i != 3) Printf(" ");
+        }
+        Printf("|");
+      }
+      Printf("\n");
+    }
+    size--;
+    s++;
+    pos++;
+  }
+
+  Printf("\n");
+
+  for (int i = 0; i < origin_set.size(); ++i) {
+    u32 o = origin_set.get(i);
+    Printf("Origin %c (origin_id %x):\n", OriginSet::asChar(i), o);
+    DescribeOrigin(o);
+  }
+}
+
 }  // namespace __msan
diff --git a/compiler-rt/test/msan/msan_dump_shadow.cc b/compiler-rt/test/msan/msan_dump_shadow.cc
new file mode 100644
index 000000000000..507a09991551
--- /dev/null
+++ b/compiler-rt/test/msan/msan_dump_shadow.cc
@@ -0,0 +1,22 @@
+// RUN: %clangxx_msan -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+#include <sanitizer/msan_interface.h>
+
+int main(void) {
+  char *p = new char[16];
+  __msan_dump_shadow(p, 5);
+  delete[] p;
+  const char *q = "abc";
+  __msan_dump_shadow(q, 3);
+  return 0;
+}
+
+// CHECK: ff ff ff ff ff
+// CHECK: 00 00 00
diff --git a/compiler-rt/test/msan/msan_print_shadow.cc b/compiler-rt/test/msan/msan_print_shadow.cc
new file mode 100644
index 000000000000..b33bae0e94f8
--- /dev/null
+++ b/compiler-rt/test/msan/msan_print_shadow.cc
@@ -0,0 +1,122 @@
+// RUN: %clangxx_msan -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NO-ORIGINS < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ORIGINS < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ORIGINS --check-prefix=CHECK-ORIGINS-2 < %t.out
+
+#include <sanitizer/msan_interface.h>
+
+int main(void) {
+  char volatile x;
+  char *p = new char[320];
+  p[2] = p[5] = 1;
+  p[8] = p[9] = p[10] = p[11] = p[12] = 2;
+
+  __msan_allocated_memory(p + 4*3, 4);
+  __msan_allocated_memory(p + 4*4, 4);
+  __msan_allocated_memory(p + 4*5, 4);
+  __msan_allocated_memory(p + 4*6, 4);
+  __msan_allocated_memory(p + 4*7, 4);
+  __msan_allocated_memory(p + 4*8, 4);
+  __msan_allocated_memory(p + 4*9, 4);
+  __msan_allocated_memory(p + 4*10, 4);
+  __msan_allocated_memory(p + 4*11, 4);
+  __msan_allocated_memory(p + 4*12, 4);
+  __msan_allocated_memory(p + 4*13, 4);
+  __msan_allocated_memory(p + 4*14, 4);
+  __msan_allocated_memory(p + 4*15, 4);
+  __msan_allocated_memory(p + 4*16, 4);
+  __msan_allocated_memory(p + 4*17, 4);
+  __msan_allocated_memory(p + 4*18, 4);
+  __msan_allocated_memory(p + 4*19, 4);
+  __msan_allocated_memory(p + 4*20, 4);
+  __msan_allocated_memory(p + 4*21, 4);
+  __msan_allocated_memory(p + 4*22, 4);
+  __msan_allocated_memory(p + 4*23, 4);
+  __msan_allocated_memory(p + 4*24, 4);
+  __msan_allocated_memory(p + 4*25, 4);
+  __msan_allocated_memory(p + 4*26, 4);
+  __msan_allocated_memory(p + 4*27, 4);
+  __msan_allocated_memory(p + 4*28, 4);
+  __msan_allocated_memory(p + 4*29, 4);
+  __msan_allocated_memory(p + 4*30, 4);
+  __msan_allocated_memory(p + 4*31, 4);
+
+  p[19] = x;
+
+  __msan_print_shadow(p+5, 297);
+  delete[] p;
+  return 0;
+}
+
+// CHECK: Shadow map of [{{.*}}), 297 bytes:
+
+// CHECK-NO-ORIGINS: 0x{{.*}}: ..00ffff 00000000 ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff
+// CHECK-NO-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffff.... ........
+
+// CHECK-ORIGINS: 0x{{.*}}: ..00ffff 00000000 ffffffff ffffffff  |A . B C|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |D E F G|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |H I J K|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |L M N O|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |P Q R S|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |T U V W|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |X Y Z *|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |* * * A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffffffff ffffffff  |A A A A|
+// CHECK-ORIGINS: 0x{{.*}}: ffffffff ffffffff ffff.... ........  |A A A .|
+
+// CHECK-ORIGINS: Origin A (origin_id {{.*}}):
+// CHECK-ORIGINS:   Uninitialized value was created by a heap allocation
+// CHECK-ORIGINS:     #1 {{.*}} in main{{.*}}msan_print_shadow.cc:14
+
+// CHECK-ORIGINS: Origin B (origin_id {{.*}}):
+// CHECK-ORIGINS:   Uninitialized value was created by a heap allocation
+// CHECK-ORIGINS:     #0 {{.*}} in __msan_allocated_memory
+// CHECK-ORIGINS:     #1 {{.*}} in main{{.*}}msan_print_shadow.cc:18
+
+// CHECK-ORIGINS: Origin C (origin_id {{.*}}):
+// CHECK-ORIGINS-2:  Uninitialized value was stored to memory at
+// CHECK-ORIGINS-2:    #0 {{.*}} in main{{.*}}msan_print_shadow.cc:48
+// CHECK-ORIGINS:   Uninitialized value was created by an allocation of 'x' in the stack frame of function 'main'
+// CHECK-ORIGINS:     #0 {{.*}} in main{{.*}}msan_print_shadow.cc:12
+
+// CHECK-ORIGINS: Origin D (origin_id {{.*}}):
+// CHECK-ORIGINS:   Uninitialized value was created by a heap allocation
+// CHECK-ORIGINS:     #0 {{.*}} in __msan_allocated_memory
+// CHECK-ORIGINS:     #1 {{.*}} in main{{.*}}msan_print_shadow.cc:20
+
+// ...
+
+// CHECK-ORIGINS: Origin Z (origin_id {{.*}}):
+// CHECK-ORIGINS:   Uninitialized value was created by a heap allocation
+// CHECK-ORIGINS:     #0 {{.*}} in __msan_allocated_memory
+// CHECK-ORIGINS:     #1 {{.*}} in main{{.*}}msan_print_shadow.cc:42
diff --git a/compiler-rt/test/msan/msan_print_shadow2.cc b/compiler-rt/test/msan/msan_print_shadow2.cc
new file mode 100644
index 000000000000..bd7a7879449f
--- /dev/null
+++ b/compiler-rt/test/msan/msan_print_shadow2.cc
@@ -0,0 +1,49 @@
+// RUN: %clangxx_msan -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NO-ORIGINS < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ORIGINS < %t.out
+
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -m64 -O0 -g %s -o %t && %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-ORIGINS < %t.out
+
+#include <sanitizer/msan_interface.h>
+
+int main(void) {
+  char *p = new char[16];
+  __msan_print_shadow(p, 1);
+  __msan_print_shadow(p+1, 1);
+  __msan_print_shadow(p+3, 1);
+  __msan_print_shadow(p+15, 1);
+  __msan_print_shadow(p, 0);
+  delete[] p;
+  const char *q = "abc";
+  __msan_print_shadow(q, 3);
+  return 0;
+}
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 1 bytes:
+// CHECK-NO-ORIGINS:   0x{{.*}}: ff...... ........ ........ ........
+// CHECK-ORIGINS:   0x{{.*}}: ff...... ........ ........ ........  |A . . .|
+// CHECK-ORIGINS: Origin A (origin_id {{.*}}):
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 1 bytes:
+// CHECK-NO-ORIGINS:   0x{{.*}}: ..ff.... ........ ........ ........
+// CHECK-ORIGINS:   0x{{.*}}: ..ff.... ........ ........ ........  |A . . .|
+// CHECK-ORIGINS: Origin A (origin_id {{.*}}):
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 1 bytes:
+// CHECK-NO-ORIGINS:   0x{{.*}}: ......ff ........ ........ ........
+// CHECK-ORIGINS:   0x{{.*}}: ......ff ........ ........ ........  |A . . .|
+// CHECK-ORIGINS: Origin A (origin_id {{.*}}):
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 1 bytes:
+// CHECK-NO-ORIGINS:   0x{{.*}}: ......ff ........ ........ ........
+// CHECK-ORIGINS:   0x{{.*}}: ......ff ........ ........ ........  |A . . .|
+// CHECK-ORIGINS: Origin A (origin_id {{.*}}):
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 0 bytes:
+
+// CHECK: Shadow map of [0x{{.*}}, 0x{{.*}}), 3 bytes:
+// CHECK-NO-ORIGINS:   0x{{.*}}: 000000.. ........ ........ ........
+// CHECK-ORIGINS:   0x{{.*}}: 000000.. ........ ........ ........  |. . . .|