Index: llvm/trunk/CMakeLists.txt
===================================================================
--- llvm/trunk/CMakeLists.txt
+++ llvm/trunk/CMakeLists.txt
@@ -1097,3 +1097,7 @@
   add_subdirectory(utils/benchmark)
   add_subdirectory(benchmarks)
 endif()
+
+if (LLVM_INCLUDE_UTILS AND LLVM_INCLUDE_TOOLS)
+  add_subdirectory(utils/llvm-locstats)
+endif()
Index: llvm/trunk/docs/CommandGuide/index.rst
===================================================================
--- llvm/trunk/docs/CommandGuide/index.rst
+++ llvm/trunk/docs/CommandGuide/index.rst
@@ -74,3 +74,4 @@
    llvm-build
    llvm-exegesis
    llvm-pdbutil
+   llvm-locstats
Index: llvm/trunk/docs/CommandGuide/llvm-locstats.rst
===================================================================
--- llvm/trunk/docs/CommandGuide/llvm-locstats.rst
+++ llvm/trunk/docs/CommandGuide/llvm-locstats.rst
@@ -0,0 +1,79 @@
+llvm-locstats - calculate statistics on DWARF debug location
+============================================================
+
+.. program:: llvm-locstats
+
+SYNOPSIS
+--------
+
+:program:`llvm-locstats` [*options*] [*filename*]
+
+DESCRIPTION
+-----------
+
+:program:`llvm-locstats` works like a wrapper around :program:`llvm-dwarfdump`.
+It parses :program:`llvm-dwarfdump` statistics regarding debug location by
+pretty printing it in a more human readable way.
+
+The line 0% shows the number and the percentage of DIEs with no location
+information, but the line 100% shows the information for DIEs where there is
+location information in all code section bytes (where the variable or parameter
+is in the scope). The line 50-59% shows the number and the percentage of DIEs
+where the location information is between 50 and 59 percentage of its scope
+covered.
+
+OPTIONS
+-------
+
+.. option:: -only-variables
+
+            Calculate the location statistics only for local variables.
+
+.. option:: -only-formal-parameters
+
+            Calculate the location statistics only for formal parameters.
+
+.. option:: -ignore-debug-entry-values
+
+            Ignore the location statistics on locations containing the
+            debug entry values DWARF operation.
+
+EXIT STATUS
+-----------
+
+:program:`llvm-locstats` returns 0 if the input file were parsed
+successfully. Otherwise, it returns 1.
+
+OUTPUT EXAMPLE
+--------------
+
+.. code-block:: none
+
+  =================================================
+            Debug Location Statistics
+  =================================================
+        cov%          samples       percentage(~)
+  -------------------------------------------------
+     0%                    1              16%
+     1-9%                  0               0%
+     10-19%                0               0%
+     20-29%                0               0%
+     30-39%                0               0%
+     40-49%                0               0%
+     50-99%                1              16%
+     60-69%                0               0%
+     70-79%                0               0%
+     80-89%                1              16%
+     90-99%                0               0%
+     100%                  3              50%
+  =================================================
+  -the number of debug variables processed: 6
+  -PC ranges covered: 81%
+  -------------------------------------------------
+  -total availability: 83%
+  =================================================
+
+SEE ALSO
+--------
+
+:manpage:`llvm-dwarfdump(1)`
Index: llvm/trunk/test/lit.cfg.py
===================================================================
--- llvm/trunk/test/lit.cfg.py
+++ llvm/trunk/test/lit.cfg.py
@@ -124,6 +124,11 @@
 
 opt_viewer_cmd = '%s %s/tools/opt-viewer/opt-viewer.py' % (sys.executable, config.llvm_src_root)
 
+llvm_locstats_tool = os.path.join(config.llvm_tools_dir, 'llvm-locstats')
+config.substitutions.append(
+    ('%llvm-locstats', "'%s' %s" % (config.python_executable, llvm_locstats_tool)))
+config.llvm_locstats_used = os.path.exists(llvm_locstats_tool)
+
 tools = [
     ToolSubst('%lli', FindTool('lli'), post='.', extra_args=lli_args),
     ToolSubst('%llc_dwarf', FindTool('llc'), extra_args=llc_args),
Index: llvm/trunk/test/tools/llvm-locstats/lit.local.cfg
===================================================================
--- llvm/trunk/test/tools/llvm-locstats/lit.local.cfg
+++ llvm/trunk/test/tools/llvm-locstats/lit.local.cfg
@@ -0,0 +1,2 @@
+if not config.llvm_locstats_used:
+    config.unsupported = True
Index: llvm/trunk/test/tools/llvm-locstats/locstats.ll
===================================================================
--- llvm/trunk/test/tools/llvm-locstats/locstats.ll
+++ llvm/trunk/test/tools/llvm-locstats/locstats.ll
@@ -0,0 +1,173 @@
+; RUN: llc %s -o %t0.o -filetype=obj \
+; RUN:   | %llvm-locstats %t0.o | FileCheck %s --check-prefix=LOCSTATS
+;
+; Test the llvm-locstats output.
+; LOCSTATS: 0% 0 0%
+; LOCSTATS: 1-9% 0 0%
+; LOCSTATS: 10-19% 0 0%
+; LOCSTATS: 20-29% 1 11%
+; LOCSTATS: 30-39% 0 0%
+; LOCSTATS: 40-49% 1 11%
+; LOCSTATS: 50-59% 1 11%
+; LOCSTATS: 60-69% 1 11%
+; LOCSTATS: 70-79% 0 0%
+; LOCSTATS: 80-89% 2 22%
+; LOCSTATS: 90-99% 1 11%
+; LOCSTATS: 100% 2 22%
+;
+; The source code of the test case:
+;extern int fn2 (int);
+;
+;__attribute__((noinline))
+;int
+;fn1 (int *x, int *y)
+;{
+;  int a = *x;
+;  int b = *y;
+;  int local = a + b;
+;  if (a > 1) {
+;    local += 2;
+;    ++local;
+;    if (local > 200)
+;      local -= fn2(a);
+;  } else {
+;    local += 3;
+;    ++local;
+;    local += fn2(a);
+; }
+;  if (b > 4)
+;   local += a;
+;  int local2 = 7;
+;  local -= fn2 (local2);
+;  return local;
+;}
+;
+;__attribute__((noinline))
+;int f()
+;{
+;  int l, k;
+;  int res = 0;
+;  res += fn1 (&l, &k);
+;  return res;
+;}
+;
+; ModuleID = 'locstats.c'
+source_filename = "locstats.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i32 @fn1(i32* nocapture readonly %0, i32* nocapture readonly %1) local_unnamed_addr !dbg !7 {
+  call void @llvm.dbg.value(metadata i32* %0, metadata !13, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32* %1, metadata !14, metadata !DIExpression()), !dbg !19
+  %3 = load i32, i32* %0, align 4, !dbg !20
+  call void @llvm.dbg.value(metadata i32 %3, metadata !15, metadata !DIExpression()), !dbg !19
+  %4 = load i32, i32* %1, align 4, !dbg !20
+  call void @llvm.dbg.value(metadata i32 %4, metadata !16, metadata !DIExpression()), !dbg !19
+  %5 = add nsw i32 %4, %3, !dbg !20
+  call void @llvm.dbg.value(metadata i32 %5, metadata !17, metadata !DIExpression()), !dbg !19
+  %6 = icmp sgt i32 %3, 1, !dbg !20
+  br i1 %6, label %7, label %13, !dbg !22
+
+7:                                                ; preds = %2
+  call void @llvm.dbg.value(metadata i32 %5, metadata !17, metadata !DIExpression(DW_OP_plus_uconst, 2, DW_OP_stack_value)), !dbg !19
+  %8 = add nsw i32 %5, 3, !dbg !23
+  call void @llvm.dbg.value(metadata i32 %8, metadata !17, metadata !DIExpression()), !dbg !19
+  %9 = icmp sgt i32 %8, 200, !dbg !25
+  br i1 %9, label %10, label %17, !dbg !27
+
+10:                                               ; preds = %7
+  %11 = tail call i32 @fn2(i32 %3), !dbg !27
+  %12 = sub nsw i32 %8, %11, !dbg !27
+  call void @llvm.dbg.value(metadata i32 %12, metadata !17, metadata !DIExpression()), !dbg !19
+  br label %17, !dbg !27
+
+13:                                               ; preds = %2
+  call void @llvm.dbg.value(metadata i32 %5, metadata !17, metadata !DIExpression(DW_OP_plus_uconst, 3, DW_OP_stack_value)), !dbg !19
+  %14 = add nsw i32 %5, 4, !dbg !28
+  call void @llvm.dbg.value(metadata i32 %14, metadata !17, metadata !DIExpression()), !dbg !19
+  %15 = tail call i32 @fn2(i32 %3), !dbg !30
+  %16 = add nsw i32 %14, %15, !dbg !30
+  call void @llvm.dbg.value(metadata i32 %16, metadata !17, metadata !DIExpression()), !dbg !19
+  br label %17
+
+17:                                               ; preds = %7, %10, %13
+  %18 = phi i32 [ %12, %10 ], [ %8, %7 ], [ %16, %13 ], !dbg !31
+  call void @llvm.dbg.value(metadata i32 %18, metadata !17, metadata !DIExpression()), !dbg !19
+  %19 = icmp sgt i32 %4, 4, !dbg !32
+  %20 = select i1 %19, i32 %3, i32 0, !dbg !34
+  %21 = add nsw i32 %18, %20, !dbg !34
+  call void @llvm.dbg.value(metadata i32 %21, metadata !17, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32 7, metadata !18, metadata !DIExpression()), !dbg !19
+  %22 = tail call i32 @fn2(i32 7), !dbg !34
+  %23 = sub i32 %21, %22, !dbg !34
+  call void @llvm.dbg.value(metadata i32 %23, metadata !17, metadata !DIExpression()), !dbg !19
+  ret i32 %23, !dbg !34
+}
+
+declare dso_local i32 @fn2(i32) local_unnamed_addr
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i32 @f() local_unnamed_addr !dbg !35 {
+  %1 = alloca i32, align 4
+  %2 = alloca i32, align 4
+  %3 = bitcast i32* %1 to i8*, !dbg !42
+  %4 = bitcast i32* %2 to i8*, !dbg !42
+  call void @llvm.dbg.value(metadata i32 0, metadata !41, metadata !DIExpression()), !dbg !42
+  call void @llvm.dbg.value(metadata i32* %1, metadata !39, metadata !DIExpression(DW_OP_deref)), !dbg !42
+  call void @llvm.dbg.value(metadata i32* %2, metadata !40, metadata !DIExpression(DW_OP_deref)), !dbg !42
+  %5 = call i32 @fn1(i32* nonnull %1, i32* nonnull %2), !dbg !42
+  call void @llvm.dbg.value(metadata i32 %5, metadata !41, metadata !DIExpression()), !dbg !42
+  ret i32 %5, !dbg !42
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "locstats.c", directory: "/dir")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 10.0.0"}
+!7 = distinct !DISubprogram(name: "fn1", scope: !1, file: !1, line: 5, type: !8, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !12)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10, !11, !11}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !10, size: 64)
+!12 = !{!13, !14, !15, !16, !17, !18}
+!13 = !DILocalVariable(name: "x", arg: 1, scope: !7, file: !1, line: 5, type: !11)
+!14 = !DILocalVariable(name: "y", arg: 2, scope: !7, file: !1, line: 5, type: !11)
+!15 = !DILocalVariable(name: "a", scope: !7, file: !1, line: 7, type: !10)
+!16 = !DILocalVariable(name: "b", scope: !7, file: !1, line: 8, type: !10)
+!17 = !DILocalVariable(name: "local", scope: !7, file: !1, line: 9, type: !10)
+!18 = !DILocalVariable(name: "local2", scope: !7, file: !1, line: 22, type: !10)
+!19 = !DILocation(line: 0, scope: !7)
+!20 = !DILocation(line: 7, column: 11, scope: !7)
+!21 = distinct !DILexicalBlock(scope: !7, file: !1, line: 10, column: 7)
+!22 = !DILocation(line: 10, column: 7, scope: !7)
+!23 = !DILocation(line: 12, column: 5, scope: !24)
+!24 = distinct !DILexicalBlock(scope: !21, file: !1, line: 10, column: 14)
+!25 = !DILocation(line: 13, column: 15, scope: !26)
+!26 = distinct !DILexicalBlock(scope: !24, file: !1, line: 13, column: 9)
+!27 = !DILocation(line: 13, column: 9, scope: !24)
+!28 = !DILocation(line: 17, column: 5, scope: !26)
+!29 = distinct !DILexicalBlock(scope: !21, file: !1, line: 15, column: 10)
+!30 = !DILocation(line: 18, column: 14, scope: !29)
+!31 = !DILocation(line: 0, scope: !21)
+!32 = !DILocation(line: 20, column: 9, scope: !33)
+!33 = distinct !DILexicalBlock(scope: !7, file: !1, line: 20, column: 7)
+!34 = !DILocation(line: 20, column: 7, scope: !7)
+!35 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 28, type: !36, scopeLine: 29, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !38)
+!36 = !DISubroutineType(types: !37)
+!37 = !{!10}
+!38 = !{!39, !40, !41}
+!39 = !DILocalVariable(name: "l", scope: !35, file: !1, line: 30, type: !10)
+!40 = !DILocalVariable(name: "k", scope: !35, file: !1, line: 30, type: !10)
+!41 = !DILocalVariable(name: "res", scope: !35, file: !1, line: 31, type: !10)
+!42 = !DILocation(line: 30, column: 3, scope: !35)
Index: llvm/trunk/utils/llvm-locstats/CMakeLists.txt
===================================================================
--- llvm/trunk/utils/llvm-locstats/CMakeLists.txt
+++ llvm/trunk/utils/llvm-locstats/CMakeLists.txt
@@ -0,0 +1,7 @@
+if (LLVM_BUILD_UTILS AND LLVM_BUILD_TOOLS)
+  add_custom_target(llvm-locstats ALL
+    COMMAND  ${CMAKE_COMMAND} -E copy ${LLVM_MAIN_SRC_DIR}/utils/llvm-locstats/llvm-locstats.py ${LLVM_TOOLS_BINARY_DIR}/llvm-locstats
+    COMMENT "Copying llvm-locstats into ${LLVM_TOOLS_BINARY_DIR}"
+    )
+  set_target_properties(llvm-locstats PROPERTIES FOLDER "Tools")
+endif()
Index: llvm/trunk/utils/llvm-locstats/llvm-locstats.py
===================================================================
--- llvm/trunk/utils/llvm-locstats/llvm-locstats.py
+++ llvm/trunk/utils/llvm-locstats/llvm-locstats.py
@@ -0,0 +1,208 @@
+#!/usr/bin/env python
+#
+# This is a tool that works like debug location coverage calculator.
+# It parses the llvm-dwarfdump --statistics output by reporting it
+# in a more human readable way.
+#
+
+from __future__ import print_function
+import argparse
+import os
+import sys
+from json import loads
+from math import ceil
+from subprocess import Popen, PIPE
+
+def coverage_buckets():
+  yield '0%'
+  yield '1-9%'
+  for start in range(10, 91, 10):
+    yield '{0}-{1}%'.format(start, start + 9)
+  yield '100%'
+
+def locstats_output(
+  variables_total,
+  variables_total_locstats,
+  variables_with_loc,
+  scope_bytes_covered,
+  scope_bytes_from_first_def,
+  variables_coverage_map
+  ):
+
+  pc_ranges_covered = int(ceil(scope_bytes_covered * 100.0)
+              / scope_bytes_from_first_def)
+  variables_coverage_per_map = {}
+  for cov_bucket in coverage_buckets():
+    variables_coverage_per_map[cov_bucket] = \
+      int(ceil(variables_coverage_map[cov_bucket] * 100.0) \
+               / variables_total_locstats)
+
+  print (' =================================================')
+  print ('            Debug Location Statistics       ')
+  print (' =================================================')
+  print ('     cov%          samples          percentage(~)  ')
+  print (' -------------------------------------------------')
+  for cov_bucket in coverage_buckets():
+    print ('   {0:6}        {1:8d}             {2:3d}%'. \
+      format(cov_bucket, variables_coverage_map[cov_bucket], \
+             variables_coverage_per_map[cov_bucket]))
+  print (' =================================================')
+  print (' -the number of debug variables processed: ' \
+    + str(variables_total_locstats))
+  print (' -PC ranges covered: ' + str(pc_ranges_covered) + '%')
+
+  # Only if we are processing all the variables output the total
+  # availability.
+  if variables_total and variables_with_loc:
+    total_availability = int(ceil(variables_with_loc * 100.0) \
+                                  / variables_total)
+    print (' -------------------------------------------------')
+    print (' -total availability: ' + str(total_availability) + '%')
+  print (' =================================================')
+
+def parse_program_args(parser):
+  parser.add_argument('-only-variables', action='store_true',
+            default=False,
+            help='calculate the location statistics only for '
+               'local variables'
+            )
+  parser.add_argument('-only-formal-parameters', action='store_true',
+            default=False,
+            help='calculate the location statistics only for '
+               'formal parameters'
+            )
+  parser.add_argument('-ignore-debug-entry-values', action='store_true',
+            default=False,
+            help='ignore the location statistics on locations with '
+               'entry values'
+            )
+  parser.add_argument('file_name', type=str, help='file to process')
+  return parser.parse_args()
+
+
+def Main():
+  parser = argparse.ArgumentParser()
+  results = parse_program_args(parser)
+
+  if len(sys.argv) < 2:
+    print ('error: Too few arguments.')
+    parser.print_help()
+    sys.exit(1)
+
+  if results.only_variables and results.only_formal_parameters:
+    print ('error: Please use just one only* option.')
+    parser.print_help()
+    sys.exit(1)
+
+  # These will be different due to different options enabled.
+  variables_total = None
+  variables_total_locstats = None
+  variables_with_loc = None
+  variables_scope_bytes_covered = None
+  variables_scope_bytes_from_first_def = None
+  variables_scope_bytes_entry_values = None
+  variables_coverage_map = {}
+  binary = results.file_name
+
+  # Get the directory of the LLVM tools.
+  llvm_dwarfdump_cmd = os.path.join(os.path.dirname(__file__), \
+                                    "llvm-dwarfdump")
+  # The statistics llvm-dwarfdump option.
+  llvm_dwarfdump_stats_opt = "--statistics"
+
+  subproc = Popen([llvm_dwarfdump_cmd, llvm_dwarfdump_stats_opt, binary], \
+                  stdin=PIPE, stdout=PIPE, stderr=PIPE, \
+                  universal_newlines = True)
+  cmd_stdout, cmd_stderr = subproc.communicate()
+
+  # Get the JSON and parse it.
+  json_parsed = None
+
+  try:
+    json_parsed = loads(cmd_stdout)
+  except:
+    print ('error: No valid llvm-dwarfdump statistics found.')
+    sys.exit(1)
+
+  if results.only_variables:
+    # Read the JSON only for local variables.
+    variables_total_locstats = \
+      json_parsed['total vars procesed by location statistics']
+    variables_scope_bytes_covered = \
+      json_parsed['vars scope bytes covered']
+    variables_scope_bytes_from_first_def = \
+      json_parsed['vars scope bytes total']
+    if not results.ignore_debug_entry_values:
+      for cov_bucket in coverage_buckets():
+        cov_category = "vars with {} of its scope covered".format(cov_bucket)
+        variables_coverage_map[cov_bucket] = json_parsed[cov_category]
+    else:
+      variables_scope_bytes_entry_values = \
+        json_parsed['vars entry value scope bytes covered']
+      variables_scope_bytes_covered = variables_scope_bytes_covered \
+         - variables_scope_bytes_entry_values
+      for cov_bucket in coverage_buckets():
+        cov_category = \
+          "vars (excluding the debug entry values) " \
+          "with {} of its scope covered".format(cov_bucket)
+        variables_coverage_map[cov_bucket] = json_parsed[cov_category]
+  elif results.only_formal_parameters:
+    # Read the JSON only for formal parameters.
+    variables_total_locstats = \
+      json_parsed['total params procesed by location statistics']
+    variables_scope_bytes_covered = \
+      json_parsed['formal params scope bytes covered']
+    variables_scope_bytes_from_first_def = \
+      json_parsed['formal params scope bytes total']
+    if not results.ignore_debug_entry_values:
+      for cov_bucket in coverage_buckets():
+        cov_category = "params with {} of its scope covered".format(cov_bucket)
+        variables_coverage_map[cov_bucket] = json_parsed[cov_category]
+    else:
+      variables_scope_bytes_entry_values = \
+        json_parsed['formal params entry value scope bytes covered']
+      variables_scope_bytes_covered = variables_scope_bytes_covered \
+        - variables_scope_bytes_entry_values
+      for cov_bucket in coverage_buckets():
+        cov_category = \
+          "params (excluding the debug entry values) " \
+          "with {} of its scope covered".format(cov_bucket)
+  else:
+    # Read the JSON for both local variables and formal parameters.
+    variables_total = \
+      json_parsed['source variables']
+    variables_with_loc = json_parsed['variables with location']
+    variables_total_locstats = \
+      json_parsed['total variables procesed by location statistics']
+    variables_scope_bytes_covered = \
+      json_parsed['scope bytes covered']
+    variables_scope_bytes_from_first_def = \
+      json_parsed['scope bytes total']
+    if not results.ignore_debug_entry_values:
+      for cov_bucket in coverage_buckets():
+        cov_category = "variables with {} of its scope covered". \
+                       format(cov_bucket)
+        variables_coverage_map[cov_bucket] = json_parsed[cov_category]
+    else:
+      variables_scope_bytes_entry_values = \
+        json_parsed['entry value scope bytes covered']
+      variables_scope_bytes_covered = variables_scope_bytes_covered \
+        - variables_scope_bytes_entry_values
+      for cov_bucket in coverage_buckets():
+        cov_category = "variables (excluding the debug entry values) " \
+                       "with {} of its scope covered". format(cov_bucket)
+        variables_coverage_map[cov_bucket] = json_parsed[cov_category]
+
+  # Pretty print collected info.
+  locstats_output(
+    variables_total,
+    variables_total_locstats,
+    variables_with_loc,
+    variables_scope_bytes_covered,
+    variables_scope_bytes_from_first_def,
+    variables_coverage_map
+    )
+
+if __name__ == '__main__':
+  Main()
+  sys.exit(0)