diff --git a/llvm/lib/Support/Signals.cpp b/llvm/lib/Support/Signals.cpp
--- a/llvm/lib/Support/Signals.cpp
+++ b/llvm/lib/Support/Signals.cpp
@@ -72,6 +72,7 @@
 
 constexpr char DisableSymbolizationEnv[] = "LLVM_DISABLE_SYMBOLIZATION";
 constexpr char LLVMSymbolizerPathEnv[] = "LLVM_SYMBOLIZER_PATH";
+constexpr char EnableSymbolizerMarkupEnv[] = "LLVM_ENABLE_SYMBOLIZER_MARKUP";
 
 // Callbacks to run in signal handler must be lock-free because a signal handler
 // could be running as we add new callbacks. We don't add unbounded numbers of
@@ -252,6 +253,25 @@
   return true;
 }
 
+static bool printMarkupContext(raw_ostream &OS, const char *MainExecutableName);
+
+LLVM_ATTRIBUTE_USED
+static bool printMarkupStackTrace(StringRef Argv0, void **StackTrace, int Depth,
+                                  raw_ostream &OS) {
+  const char *Env = getenv(EnableSymbolizerMarkupEnv);
+  if (!Env || !*Env)
+    return false;
+
+  std::string MainExecutableName =
+      sys::fs::exists(Argv0) ? std::string(Argv0)
+                             : sys::fs::getMainExecutable(nullptr, nullptr);
+  if (!printMarkupContext(OS, MainExecutableName.c_str()))
+    return false;
+  for (int I = 0; I < Depth; I++)
+    OS << format("{{{bt:%d:%#016x}}}\n", I, StackTrace[I]);
+  return true;
+}
+
 // Include the platform-specific parts of this class.
 #ifdef LLVM_ON_UNIX
 #include "Unix/Signals.inc"
diff --git a/llvm/lib/Support/Unix/Signals.inc b/llvm/lib/Support/Unix/Signals.inc
--- a/llvm/lib/Support/Unix/Signals.inc
+++ b/llvm/lib/Support/Unix/Signals.inc
@@ -509,6 +509,115 @@
   dl_iterate_phdr(dl_iterate_phdr_cb, &data);
   return true;
 }
+
+class DSOMarkupPrinter {
+public:
+  DSOMarkupPrinter(llvm::raw_ostream &OS, const char *MainExecutableName) :
+      OS(OS), MainExecutableName(MainExecutableName) {}
+
+  /// Print llvm-symbolizer markup describing the layout of the given DSO.
+  void printDSOMarkup(dl_phdr_info *Info) {
+    ArrayRef<uint8_t> BuildID = findBuildID(Info);
+    if (BuildID.empty())
+      return;
+    OS << format("{{{module:%d:%s:elf:", ModuleCount,
+                 IsFirst ? MainExecutableName : Info->dlpi_name);
+    for (uint8_t X : BuildID)
+      OS << format("%02x", X);
+    OS << "}}}\n";
+
+    for (int I = 0; I < Info->dlpi_phnum; I++) {
+      const auto *Phdr = &Info->dlpi_phdr[I];
+      if (Phdr->p_type != PT_LOAD)
+        continue;
+      uintptr_t StartAddress = Info->dlpi_addr + Phdr->p_vaddr;
+      uintptr_t ModuleRelativeAddress = Phdr->p_vaddr;
+      char ModeStr[4];
+      fillModeStr(Phdr->p_flags, ModeStr);
+      OS << format("{{{mmap:%#016x:%#x:load:%d:%s:%#016x}}}\n",
+                   StartAddress, Phdr->p_memsz, ModuleCount, (char*)ModeStr,
+                   ModuleRelativeAddress);
+    }
+    IsFirst = false;
+    ModuleCount++;
+  }
+
+  /// Callback for use with dl_iterate_phdr. The last dl_iterate_phdr argument
+  /// must be a pointer to an instance of this class.
+  static int printDSOMarkup(dl_phdr_info *Info, size_t Size, void *Arg) {
+    static_cast<DSOMarkupPrinter*>(Arg)->printDSOMarkup(Info);
+    return 0;
+  }
+
+  // Returns the build ID for the given DSO as an array of bytes. Returns an
+  // empty array if none could be found.
+  ArrayRef<uint8_t> findBuildID(dl_phdr_info *Info) {
+    for (int I = 0; I < Info->dlpi_phnum; I++) {
+      const auto *Phdr = &Info->dlpi_phdr[I];
+      if (Phdr->p_type != PT_NOTE)
+        continue;
+
+      ArrayRef<uint8_t> Notes(
+          (const uint8_t *)(Info->dlpi_addr + Phdr->p_vaddr),
+          Phdr->p_memsz);
+      while (Notes.size() > 12) {
+        uint32_t NameSize = *(const uint32_t *)(Notes.data());
+        Notes = Notes.drop_front(4);
+        uint32_t DescSize = *(const uint32_t *)(Notes.data());
+        Notes = Notes.drop_front(4);
+        uint32_t Type = *(const uint32_t *)(Notes.data());
+        Notes = Notes.drop_front(4);
+
+        ArrayRef<uint8_t> Name = Notes.take_front(NameSize);
+        uint32_t AmtToSkip =
+            alignToPowerOf2((uintptr_t)Notes.data() + NameSize, 4) -
+            (uintptr_t)Notes.data();
+        if (AmtToSkip >= Notes.size())
+          break;
+        Notes = Notes.drop_front(AmtToSkip);
+
+        ArrayRef<uint8_t> Desc = Notes.take_front(DescSize);
+        AmtToSkip = alignToPowerOf2((uintptr_t)Notes.data() + DescSize, 4) -
+                    (uintptr_t)Notes.data();
+        if (AmtToSkip > Notes.size())
+          break;
+        Notes = Notes.drop_front(AmtToSkip);
+
+        if (Type == 3/*NT_GNU_BUILD_ID*/ && Name.size() >= 3 &&
+            Name[0] == 'G' && Name[1] == 'N' && Name[2] == 'U')
+          return Desc;
+      }
+    }
+    return {};
+  }
+
+  // Produces a symbolizer markup string describing the permissions on a DSO
+  // with the given p_flags. The incoming pointer must point to an object of at
+  // least 4 bytes.
+  void fillModeStr(uint32_t Flags, char *Str) {
+    if (Flags & PF_R)
+      *Str++ = 'r';
+    if (Flags & PF_W)
+      *Str++ = 'w';
+    if (Flags & PF_X)
+      *Str++ = 'x';
+    *Str = '\0';
+  }
+
+private:
+  llvm::raw_ostream &OS;
+  const char *MainExecutableName;
+  size_t ModuleCount = 0;
+  bool IsFirst = true;
+};
+
+static bool printMarkupContext(llvm::raw_ostream &OS,
+                               const char *MainExecutableName) {
+  OS << "{{{reset}}}\n";
+  DSOMarkupPrinter MP(OS, MainExecutableName);
+  dl_iterate_phdr(DSOMarkupPrinter::printDSOMarkup, &MP);
+  return true;
+}
 #else
 /// This platform does not have dl_iterate_phdr, so we do not yet know how to
 /// find all loaded DSOs.
@@ -518,6 +627,11 @@
                                   StringSaver &StrPool) {
   return false;
 }
+
+static bool printMarkupContext(llvm::raw_ostream &OS,
+                               const char *MainExecutableName) {
+  return false;
+}
 #endif // defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES && ...
 
 #if ENABLE_BACKTRACES && defined(HAVE__UNWIND_BACKTRACE)
@@ -578,6 +692,8 @@
   // backtrace() for printing a symbolized stack trace.
   if (!Depth)
     Depth = depth;
+  if (printMarkupStackTrace(Argv0, StackTrace, Depth, OS))
+    return;
   if (printSymbolizedStackTrace(Argv0, StackTrace, Depth, OS))
     return;
   OS << "Stack dump without symbol names (ensure you have llvm-symbolizer in "
diff --git a/llvm/unittests/Support/CMakeLists.txt b/llvm/unittests/Support/CMakeLists.txt
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -74,6 +74,7 @@
   ScaledNumberTest.cpp
   ScopedPrinterTest.cpp
   SHA256.cpp
+  SignalsTest.cpp
   SourceMgrTest.cpp
   SpecialCaseListTest.cpp
   SuffixTreeTest.cpp
diff --git a/llvm/unittests/Support/SignalsTest.cpp b/llvm/unittests/Support/SignalsTest.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/unittests/Support/SignalsTest.cpp
@@ -0,0 +1,65 @@
+//===-- llvm/unittest/Support/SignalsTest.cpp - Signals unit tests --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains unit tests for Signals.cpp and Signals.inc.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Signals.h"
+#include "llvm/ADT/ScopeExit.h"
+#include "llvm/Config/config.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest-matchers.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::sys;
+using testing::MatchesRegex;
+using testing::Not;
+
+#define TAG_BEGIN "\\{\\{\\{"
+#define TAG_END "\\}\\}\\}"
+
+#if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES && HAVE_LINK_H &&             \
+    (defined(__linux__) || defined(__FreeBSD__) ||                             \
+     defined(__FreeBSD_kernel__) || defined(__NetBSD__))
+TEST(SignalsTest, PrintsSymbolizerMarkup) {
+  auto Exit =
+      make_scope_exit([]() { unsetenv("LLVM_ENABLE_SYMBOLIZER_MARKUP"); });
+  setenv("LLVM_ENABLE_SYMBOLIZER_MARKUP", "1", 1);
+  std::string Res;
+  raw_string_ostream RawStream(Res);
+  PrintStackTrace(RawStream);
+  EXPECT_THAT(Res, MatchesRegex(TAG_BEGIN "reset" TAG_END ".*"));
+  // Module line for main binary
+  EXPECT_THAT(Res,
+              MatchesRegex(".*" TAG_BEGIN
+                           "module:0:[^:]*SupportTests:elf:[0-9a-f]+" TAG_END
+                           ".*"));
+  // Text segment for main binary
+  EXPECT_THAT(
+      Res,
+      MatchesRegex(".*" TAG_BEGIN
+                   "mmap:0x[0-9a-f]+:0x[0-9a-f]+:load:0:rx:0x[0-9a-f]+" TAG_END
+                   ".*"));
+  // Backtrace line
+  EXPECT_THAT(Res, MatchesRegex(".*" TAG_BEGIN "bt:0:0x[0-9a-f]+"
+                                ".*"));
+}
+
+TEST(SignalsTest, SymbolizerMarkupDisabled) {
+  auto Exit = make_scope_exit([]() { unsetenv("LLVM_DISABLE_SYMBOLIZATION"); });
+  setenv("LLVM_DISABLE_SYMBOLIZATION", "1", 1);
+  std::string Res;
+  raw_string_ostream RawStream(Res);
+  PrintStackTrace(RawStream);
+  EXPECT_THAT(Res, Not(MatchesRegex(TAG_BEGIN "reset" TAG_END ".*")));
+}
+
+#endif // defined(HAVE_BACKTRACE) && ...