SuperPMI Collect/Replay/AsmDiff tool (#21252)

This change adds superpmi.py. The tool feature three modes, collection, replay, and asmdiffs.

Collection
The collection logic is very similar to the logic in our superpmi-collect test. Mostly it just allows running a script which will run managed code and it will produce a .mch which is clean to be run against. See superpmi.md for more information on specific usage and problems.

Replay
Replay will take an existing .mch file and run the current jit over the collection. If there is no .mch file on disk, the script will download the latest collection and run against that.

AsmDiffs
superpmi.md has the latest information on what platforms support asmdiffs. So far, I have an updated OSX and Windows collection that I have run against. If there are binary diffs, the tool will automatically generate base & diff folders with the asm under each one. Future work would include automatically running jit-analyze over those locations.

In addition, the tool has the option to automatically run and diff jit dumps, I have found this to be useful to looking into diffs created, as re-running superpmi with different jits to collect this same information is somewhat tedious.

Future work
This change is in no way the end of the work needed to leverage superpmi effectively. Instead, it is a good first step. Below are some suggestions for future superpmi work:

Automated collections
Add pmi collection support
Leverage some of the new corefx work to use superpmi shim for collections of corefx runs
To be added/changed
I will unset zapdisable being set by default, it creates too much data, although it is useful it should be opt in
Will include example usage in superpmi.md.

2 files changed, 1700 insertions, 0 deletions

diff --git a/scripts/superpmi.md b/scripts/superpmi.md
new file mode 100644
index 0000000000..1ea9feee7d
--- /dev/null
+++ b/scripts/superpmi.md
@@ -0,0 +1,66 @@
+### An overview of using superpmi.py
+-------------------------
+
+General information on [SuperPMI](https://github.com/dotnet/coreclr/blob/master/src/ToolBox/superpmi/readme.txt)
+
+------------------------
+
+#### Overview
+
+Although SuperPMI has many uses, setup and use of SuperPMI is not always trivial. superpmi.py is a tool to help automate the use of SuperPMI, augmenting its usefulness. The tool has three different modes, collect, replay, and asmdiffs. Below you will find more specific information on each of the different modes.
+
+**SuperPMI has a large limitation, the replay/asmdiff functionality is sensitive to jitinterface changes. Therefore if there has been an interface change, the new JIT will not load and SuperPMI will fail.**
+
+**At the time of writing collections are done manually on all platforms that support libcoredistools. See before for a full list of supported platforms and where the .mch collection exists.**
+
+#### Supported Platforms
+
+| OS | Arch | Replay | AsmDiffs | mch location |
+| --- | --- | --- |--- | --- |
+| OSX | x64 |  <ul><li>- [x] </li></ul> |  <ul><li>- [x] </li></ul> |  |
+| Windows | x64 |  <ul><li>- [x] </li></ul> |  <ul><li>- [x] </li></ul> |  |
+| Windows | x86 |  <ul><li>- [x] </li></ul> |  <ul><li>- [x] </li></ul> |  |
+| Windows | arm |  <ul><li>- [] </li></ul> |  <ul><li>- [] </li></ul> | N/A |
+| Windows | arm64 |  <ul><li>- [] </li></ul> |  <ul><li>- [] </li></ul> | N/A |
+| Ubuntu | x64 |  <ul><li>- [x] </li></ul> |  <ul><li>- [x] </li></ul> |  |
+| Ubuntu | arm32 |  <ul><li>- [] </li></ul> |  <ul><li>- [] </li></ul> | N/A |
+| Ubuntu | arm64 |  <ul><li>- [] </li></ul> |  <ul><li>- [] </li></ul> | N/A |
+
+### Default Collections
+
+See the table above for locations of default collections that exist. If there is an mch file that exists, then SuperPMI will automatically download and setup the mch using that location. Please note that, it is possible that the collection is out of date, or there is a jitinterface change which makes the collection invalid. If this is the case, then in order to use the tool a collection will have to be done manually. In order to reproduce the default collections, please see below for what command the default collections are done with.
+
+`/Users/jashoo/coreclr/build.sh x64 checked -skiptests`
+
+`/Users/jashoo/coreclr/build-test.sh x64 checked -priority1`
+
+`/Users/jashoo/coreclr/scripts/superpmi.py collect bash "/Users/jashoo/coreclr/tests/runtest.sh x64 checked" --skip-cleanup`
+
+**Collect**
+
+Given a specific command collect over all of the managed code called by the child process. Note that this allows many different invocations of any managed code. Although it does specifically require that any managed code run by the child process to handle the complus variables set by SuperPMI and defer them to the later. These are below:
+
+```
+SuperPMIShimLogPath=<full path to an empty temporary directory>
+SuperPMIShimPath=<full path to clrjit.dll, the "standalone" JIT>
+COMPlus_AltJit=*
+COMPlus_AltJitName=superpmi-shim-collector.dll
+```
+
+If these variables are set and a managed exe is run, using for example the dotnetcli, the altjit settings will crash the process.
+
+To avoid this, the easiest way is to unset the variables in the beginning to the root process, and then set them right before calling $CORE_ROOT/corerun.
+
+Note that collection will try to run as much managed code as possible. In order to do this, `COMPlus_ZapDisable=1` is set by default. This can be modified by passing `--use_r2r`.
+
+Also note that collection generates gigabytes of data, most of this data will be removed when the collection is finished and de-dupped into a single mch file. That being said, it is worth mentioning that this process will use 3x the size of the unclean mch file, which to give an example of the size, a collection of the coreclr `priority=1` tests uses roughly `200gb` of disk space. Most of this space will be used in a temp directory, which on Windows will default to `C:\Users\blah\AppData\Temp\...`. It is recommended to set the temp variable to a different location before running collect to avoid running out of disk space. This can be done by simply running `set TEMP=D:\TEMP`.
+
+**Replay**
+
+SuperPMI replay supports faster assertion checking over a collection than running the tests individually. This is useful if the collection includes a larger corpus of data that can reasonably be run against by executing the actual code. Note that this is similar to the PMI tool, with the same limitation, that runtime issues will not be caught by SuperPMI replay only assertions.
+
+**AsmDiffs**
+
+SuperPMI will take two different JITs, a baseline and diff JIT and run the compiler accross all the methods in the mch file. It uses coredistools to do a binary difference of the two different outputs. Note that sometimes the binary will differ, and SuperPMI will be run once again dumping the asm that was output in text format. Then the text will be diffed, if there are differences, you should look for text differences. If there are some then it is worth investigating the asm differences.
+
+It is worth noting as well that SuperPMI gives more stable instructions retired counters for the JIT.
\ No newline at end of file
diff --git a/scripts/superpmi.py b/scripts/superpmi.py
new file mode 100755
index 0000000000..1ccaeffc50
--- /dev/null
+++ b/scripts/superpmi.py
@@ -0,0 +1,1634 @@
+#!/usr/bin/env python
+#
+## Licensed to the .NET Foundation under one or more agreements.
+## The .NET Foundation licenses this file to you under the MIT license.
+## See the LICENSE file in the project root for more information.
+#
+##
+# Title               : superpmi.py
+#
+# Notes:
+#  
+# Script to handle running SuperPMI Collections, and replays. In addition, this
+# script provides support for SuperPMI ASM diffs. Note that some of the options
+# provided by this script are also provided in our SuperPMI collect test. The 
+# test can be found here: https://github.com/dotnet/coreclr/blob/master/tests/src/JIT/superpmi/superpmicollect.cs.
+#
+################################################################################
+################################################################################
+
+import argparse
+import datetime
+import json
+import math
+import os
+import platform
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
+import re
+import string
+import zipfile
+
+import xml.etree.ElementTree
+
+from collections import defaultdict
+from sys import platform as _platform
+
+# Version specific imports
+
+if sys.version_info.major < 3:
+    import urllib
+else:
+    import urllib.request
+
+from coreclr_arguments import *
+
+################################################################################
+# Argument Parser
+################################################################################
+
+description = ("""Script to handle running SuperPMI Collections, and replays. In addition, this
+script provides support for SuperPMI ASM diffs. Note that some of the options
+provided by this script are also provided in our SuperPMI collect test.""")
+
+superpmi_collect_help = """ Command to run SuperPMI collect over. Note that there
+cannot be any dotnet cli command invoked inside this command, as they will fail due
+to the shim altjit being set.
+"""
+
+superpmi_replay_help = """ Location of the mch file to run a replay over. Note
+that this may either be a location to a path on disk or a uri to download the
+mch file and replay it.
+"""
+
+parser = argparse.ArgumentParser(description=description)
+
+subparsers = parser.add_subparsers(dest='mode')
+
+# subparser for collect
+collect_parser = subparsers.add_parser("collect")
+
+# Add required arguments
+collect_parser.add_argument("collection_command", nargs=1, help=superpmi_collect_help)
+collect_parser.add_argument("collection_args", nargs=1, help="Arguments to pass to the SuperPMI collect command.")
+
+collect_parser.add_argument("--break_on_assert", dest="break_on_assert", default=False, action="store_true")
+collect_parser.add_argument("--break_on_error", dest="break_on_error", default=False, action="store_true")
+
+collect_parser.add_argument("-log_file", dest="log_file", default=None)
+
+collect_parser.add_argument("-arch", dest="arch", nargs='?', default="x64") 
+collect_parser.add_argument("-build_type", dest="build_type", nargs='?', default="Checked")
+collect_parser.add_argument("-test_location", dest="test_location", nargs="?", default=None)
+collect_parser.add_argument("-core_root", dest="core_root", nargs='?', default=None)
+collect_parser.add_argument("-product_location", dest="product_location", nargs='?', default=None)
+collect_parser.add_argument("-coreclr_repo_location", dest="coreclr_repo_location", default=os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+collect_parser.add_argument("-test_env", dest="test_env", default=None)
+collect_parser.add_argument("-output_mch_path", dest="output_mch_path", default=None)
+collect_parser.add_argument("-run_from_coreclr_dir", dest="run_from_coreclr_dir", default=False)
+
+collect_parser.add_argument("--use_zapdisable", dest="use_zapdisable", default=False, action="store_true", help="Allow redundant calls to the systems libraries for more coverage.")
+
+collect_parser.add_argument("--assume_unclean_mch", dest="assume_unclean_mch", default=False, action="store_true", help="Force clean the mch file. This is useful if the dataset is large and there are expected dups.")
+
+# Allow for continuing a collection in progress
+collect_parser.add_argument("-existing_temp_dir", dest="existing_temp_dir", default=None, nargs="?")
+collect_parser.add_argument("--has_run_collection_command", dest="has_run_collection_command", default=False, action="store_true")
+collect_parser.add_argument("--has_merged_mch", dest="has_merged_mch", default=False, action="store_true")
+collect_parser.add_argument("--has_verified_clean_mch", dest="has_verified_clean_mch", default=False, action="store_true")
+
+collect_parser.add_argument("--skip_collect_mc_files", dest="skip_collect_mc_files", default=False, action="store_true")
+collect_parser.add_argument("--skip_cleanup", dest="skip_cleanup", default=False, action="store_true")
+
+# subparser for replay
+replay_parser = subparsers.add_parser("replay")
+
+# Add required arguments
+replay_parser.add_argument("jit_path", nargs=1, help="Path to clrjit.")
+
+replay_parser.add_argument("-mch_file", nargs=1, help=superpmi_replay_help)
+replay_parser.add_argument("-log_file", dest="log_file", default=None)
+
+replay_parser.add_argument("--break_on_assert", dest="break_on_assert", default=False, action="store_true")
+replay_parser.add_argument("--break_on_error", dest="break_on_error", default=False, action="store_true")
+
+replay_parser.add_argument("-arch", dest="arch", nargs='?', default="x64")
+replay_parser.add_argument("-build_type", dest="build_type", nargs='?', default="Checked")
+replay_parser.add_argument("-test_location", dest="test_location", nargs="?", default=None)
+replay_parser.add_argument("-core_root", dest="core_root", nargs='?', default=None)
+replay_parser.add_argument("-product_location", dest="product_location", nargs='?', default=None)
+replay_parser.add_argument("-coreclr_repo_location", dest="coreclr_repo_location", default=os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+replay_parser.add_argument("-test_env", dest="test_env", default=None)
+replay_parser.add_argument("-output_mch_path", dest="output_mch_path", default=None)
+replay_parser.add_argument("-run_from_coreclr_dir", dest="run_from_coreclr_dir", default=False)
+
+replay_parser.add_argument("--skip_collect_mc_files", dest="skip_collect_mc_files", default=False, action="store_true")
+replay_parser.add_argument("--skip_cleanup", dest="skip_cleanup", default=False, action="store_true")
+replay_parser.add_argument("--force_download", dest="force_download", default=False, action="store_true")
+
+# subparser for asmDiffs
+asm_diff_parser = subparsers.add_parser("asmdiffs")
+
+# Add required arguments
+asm_diff_parser.add_argument("base_jit_path", nargs=1, help="Path to baseline clrjit.")
+asm_diff_parser.add_argument("diff_jit_path", nargs=1, help="Path to diff clrjit.")
+
+asm_diff_parser.add_argument("-mch_file", nargs=1, help=superpmi_replay_help)
+
+asm_diff_parser.add_argument("-log_file", dest="log_file", default=None)
+asm_diff_parser.add_argument("--break_on_assert", dest="break_on_assert", default=False, action="store_true")
+asm_diff_parser.add_argument("--break_on_error", dest="break_on_error", default=False, action="store_true")
+
+asm_diff_parser.add_argument("-arch", dest="arch", nargs='?', default="x64")
+asm_diff_parser.add_argument("-build_type", dest="build_type", nargs='?', default="Checked")
+asm_diff_parser.add_argument("-test_location", dest="test_location", nargs="?", default=None)
+asm_diff_parser.add_argument("-core_root", dest="core_root", nargs='?', default=None)
+asm_diff_parser.add_argument("-product_location", dest="product_location", nargs='?', default=None)
+asm_diff_parser.add_argument("-coreclr_repo_location", dest="coreclr_repo_location", default=os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+asm_diff_parser.add_argument("-test_env", dest="test_env", default=None)
+asm_diff_parser.add_argument("-output_mch_path", dest="output_mch_path", default=None)
+asm_diff_parser.add_argument("-run_from_coreclr_dir", dest="run_from_coreclr_dir", default=False)
+
+asm_diff_parser.add_argument("--skip_collect_mc_files", dest="skip_collect_mc_files", default=False, action="store_true")
+asm_diff_parser.add_argument("--skip_cleanup", dest="skip_cleanup", default=False, action="store_true")
+asm_diff_parser.add_argument("--force_download", dest="force_download", default=False, action="store_true")
+
+asm_diff_parser.add_argument("--diff_with_code", dest="diff_with_code", default=False, action="store_true")
+asm_diff_parser.add_argument("--diff_with_code_only", dest="diff_with_code_only", default=False, action="store_true", help="Only run the diff command, do not run SuperPMI to regenerate diffs.")
+
+asm_diff_parser.add_argument("--diff_jit_dump", dest="diff_jit_dump", default=False, action="store_true")
+asm_diff_parser.add_argument("--diff_jit_dump_only", dest="diff_jit_dump_only", default=False, action="store_true", help="Only diff jitdumps, not asm.")
+
+################################################################################
+# Helper classes
+################################################################################
+
+class TempDir:
+    def __init__(self, path=None):
+        self.dir = tempfile.mkdtemp() if path is None else path
+        self.cwd = None
+
+    def __enter__(self):
+        self.cwd = os.getcwd()
+        os.chdir(self.dir)
+
+        return self.dir
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        os.chdir(self.cwd)
+        if not args.skip_cleanup:
+            shutil.rmtree(self.dir)
+
+class ChangeDir:
+    def __init__(self, dir):
+        self.dir = dir
+        self.cwd = None
+
+    def __enter__(self):
+        self.cwd = os.getcwd()
+        os.chdir(self.dir)
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        os.chdir(self.cwd)
+
+################################################################################
+# SuperPMI Collect
+################################################################################
+
+class SuperPMICollect:
+    """ SuperPMI Collect class
+
+    Notes:
+        The object is responsible for setting up a super pmi collection given
+        the arguments passed into the script.
+    """
+
+    def __init__(self, args):
+        """ Constructor
+
+        Args:
+            args (CoreclrArguments): parsed args
+
+        """
+
+        if args.host_os == "OSX":
+            self.standalone_jit_name = "libclrjit.dylib"
+            self.collection_shim_name = "libsuperpmi-shim-collector.dylib"
+            self.superpmi_tool_name = "superpmi"
+            self.mcs_tool_name = "mcs"
+        elif args.host_os == "Linux":
+            self.standalone_jit_name = "libclrjit.so"
+            self.collection_shim_name = "libsuperpmi-shim-collector.so"
+            self.superpmi_tool_name = "superpmi"
+            self.mcs_tool_name = "mcs"
+        elif args.host_os == "Windows_NT":
+            self.standalone_jit_name = "clrjit.dll"
+            self.collection_shim_name = "superpmi-shim-collector.dll"
+            self.superpmi_tool_name = "superpmi.exe"
+            self.mcs_tool_name = "mcs.exe"
+        else:
+            raise RuntimeError("Unsupported OS.")
+
+        self.jit_path = os.path.join(args.core_root, self.standalone_jit_name)
+        self.superpmi_path = os.path.join(args.core_root, self.superpmi_tool_name)
+        self.mcs_path = os.path.join(args.core_root, self.mcs_tool_name)
+
+        self.coreclr_args = args
+
+        self.command = self.coreclr_args.collection_command
+        self.args = self.coreclr_args.collection_args
+
+    ############################################################################
+    # Instance Methods
+    ############################################################################
+
+    def collect(self):
+        """ Do the SuperPMI Collection.
+        """
+
+        # Pathname for a temporary .MCL file used for noticing SuperPMI replay failures against base MCH.
+        self.base_fail_mcl_file = None
+
+        # Pathname for a temporary .MCL file used for noticing SuperPMI replay failures against final MCH.
+        self.final_fail_mcl_file = None
+
+        # The base .MCH file path
+        self.base_mch_file = None
+
+        # Clean .MCH file path
+        self.clean_mch_file = None
+
+        # Final .MCH file path
+        self.final_mch_file = None
+
+        # The .TOC file path for the clean thin unique .MCH file
+        self.toc_file = None
+
+        self.save_the_final_mch_file = False
+
+        # Do a basic SuperPMI collect and validation:
+        #   1. Collect MC files by running a set of sample apps.
+        #   2. Merge the MC files into a single MCH using "mcs -merge *.mc -recursive".
+        #   3. Create a clean MCH by running SuperPMI over the MCH, and using "mcs -strip" to filter
+        #       out any failures (if any).
+        #    4. Create a thin unique MCH by using "mcs -removeDup -thin".
+        #    5. Create a TOC using "mcs -toc".
+        #    6. Verify the resulting MCH file is error-free when running SuperPMI against it with the
+        #       same JIT used for collection.
+        #
+        #    MCH files are big. If we don't need them anymore, clean them up right away to avoid
+        #    running out of disk space in disk constrained situations.
+
+        passed = False
+
+        try:
+            with TempDir(self.coreclr_args.existing_temp_dir) as temp_location:
+                # Setup all of the temp locations
+                self.base_fail_mcl_file = os.path.join(temp_location, "basefail.mcl")
+                self.final_fail_mcl_file = os.path.join(temp_location, "finalfail.mcl")
+                
+                self.base_mch_file = os.path.join(temp_location, "base.mch")
+                self.clean_mch_file = os.path.join(temp_location, "clean.mch")
+
+                self.temp_location = temp_location
+
+                if self.coreclr_args.output_mch_path is not None:
+                    self.save_the_final_mch_file = True
+                    self.final_mch_file = os.path.abspath(self.coreclr_args.output_mch_path)
+                    self.toc_file = self.final_mch_file + ".mct"
+                else:
+                    self.save_the_final_mch_file = True
+
+                    default_coreclr_bin_mch_location = self.coreclr_args.default_coreclr_bin_mch_location
+
+                    self.final_mch_file = os.path.join(default_coreclr_bin_mch_location, "{}.{}.{}.mch".format(self.coreclr_args.host_os, self.coreclr_args.arch, self.coreclr_args.build_type))
+                    self.toc_file = "{}.mct".format(self.final_mch_file)
+
+
+                # If we have passed existing_temp_dir, then we have a few flags we need
+                # to check to see where we are in the collection process. Note that this
+                # functionality exists to help not lose progress during a SuperPMI collection.
+
+
+                # It is not unreasonable for the SuperPMI collection to take many hours
+                # therefore allow re-use of a collection in progress
+
+                if not self.coreclr_args.has_run_collection_command:
+                    self.__collect_mc_files__(self.command, self.args)
+                
+                if not self.coreclr_args.has_merged_mch:
+                    self.__merge_mc_files__()
+
+                if not self.coreclr_args.has_verified_clean_mch:
+                    self.__create_clean_mch_file__()
+                    self.__create_thin_unique_mch__()
+                    self.__create_toc__()
+                    self.__verify_final_mch__()
+
+                passed = True
+
+        except Exception as exception:
+            print(exception)
+
+        return passed
+
+    ############################################################################
+    # Helper Methods
+    ############################################################################
+
+    def __collect_mc_files__(self, command, args):
+        """ Do the actual SuperPMI collection for a command
+
+        Args:
+            command (str)   : script/executable to run
+            args ([str])    : arguments to pass
+        
+        Returns:
+            None
+        """
+
+        if not self.coreclr_args.skip_collect_mc_files:
+            assert os.path.isdir(self.temp_location)
+
+            # Set environment variables.
+            env_copy = os.environ.copy()
+            env_copy["SuperPMIShimLogPath"] = self.temp_location
+            env_copy["SuperPMIShimPath"] = self.jit_path
+            env_copy["COMPlus_AltJit"] = "*"
+            env_copy["COMPlus_AltJitName"] = self.collection_shim_name
+
+            if self.coreclr_args.use_zapdisable:
+                env_copy["COMPlus_ZapDisable"] = "1"
+
+            print("Starting collection.")
+            print("")
+            print_platform_specific_environment_vars(self.coreclr_args, "SuperPMIShimLogPath", self.temp_location)
+            print_platform_specific_environment_vars(self.coreclr_args, "SuperPMIShimPath", self.jit_path)
+            print_platform_specific_environment_vars(self.coreclr_args, "COMPlus_AltJit", "*")
+            print_platform_specific_environment_vars(self.coreclr_args, "COMPlus_AltJitName", self.collection_shim_name)
+            print("")
+            print("%s %s" % (command, " ".join(args)))
+
+            assert isinstance(command, str)
+            assert isinstance(args, list)
+
+            return_code = 1
+
+            command = [command] + args 
+            proc = subprocess.Popen(command, env=env_copy)
+
+            proc.communicate()
+            return_code = proc.returncode
+
+        contents = os.listdir(self.temp_location)
+        mc_contents = [os.path.join(self.temp_location, item) for item in contents if ".mc" in item]
+
+        if len(mc_contents) == 0:
+            raise RuntimeError("No .mc files generated.")
+
+        self.mc_contents = mc_contents
+
+    def __merge_mc_files__(self):
+        """ Merge the mc files that were generated
+
+        Notes:
+            mcs -merge <s_baseMchFile> <s_tempDir>\*.mc -recursive
+
+        """
+
+        pattern = os.path.join(self.temp_location, "*.mc")
+
+        command = [self.mcs_path, "-merge", self.base_mch_file, pattern, "-recursive"]
+        print("Invoking: " + " ".join(command))
+        proc = subprocess.Popen(command)
+
+        proc.communicate()
+
+        if not os.path.isfile(self.mcs_path):
+            raise RuntimeError("mch file failed to be generated at: %s" % self.mcs_path)
+
+        contents = os.listdir(self.temp_location)
+        mc_contents = [os.path.join(self.temp_location, item) for item in contents if ".mc" in item and not ".mch" in item]
+
+        # All the individual MC files are no longer necessary, now that we have
+        # merged them into the base.mch. Delete them.
+        if not self.coreclr_args.skip_cleanup:
+            for item in mc_contents:
+                os.remove(item)
+    
+    def __create_clean_mch_file__(self):
+        """ Create a clean mch file based on the original
+
+        Notes:
+            <SuperPMIPath> -p -f <s_baseFailMclFile> <s_baseMchFile> <jitPath>
+
+            if <s_baseFailMclFile> is non-empty:
+                <mcl> -strip <s_baseFailMclFile> <s_baseMchFile> <s_cleanMchFile>
+            else
+                # no need to copy, just change the names
+                clean_mch_file = base_mch_file
+            del <s_baseFailMclFile>
+        """
+
+        command = [self.superpmi_path, "-p", "-f", self.base_fail_mcl_file, self.base_mch_file, self.jit_path]
+        print (" ".join(command))
+        proc = subprocess.Popen(command)
+
+        proc.communicate()
+
+        if os.path.isfile(self.base_fail_mcl_file) and os.stat(self.base_fail_mcl_file).st_size != 0:
+            command = [self.mcs_path, "-strip", self.base_fail_mcl_file, self.base_mch_file, self.clean_mch_file]
+            print (" ".join(command))
+            proc = subprocess.Popen(command)
+
+            proc.communicate()
+        else:
+            self.clean_mch_file = self.base_mch_file
+            self.base_mch_file = None
+
+        if not os.path.isfile(self.clean_mch_file):
+            raise RuntimeError("Clean mch file failed to be generated.")
+
+        if not self.coreclr_args.skip_cleanup:
+            if os.path.isfile(self.base_fail_mcl_file):
+                os.remove(self.base_fail_mcl_file)
+                self.base_fail_mcl_file = None
+
+            # The base file is no longer used (unless there was no cleaning done, in which case
+            # self.base_mch_file has been set to None and clean_mch_File is the base file).
+            if os.path.isfile(self.base_mch_file):
+                os.remove(self.base_mch_file)
+                self.base_mch_file = None
+
+    def __create_thin_unique_mch__(self):
+        """  Create a thin unique MCH
+        
+        Notes:
+            <mcl> -removeDup -thin <s_cleanMchFile> <s_finalMchFile>
+        """
+
+        command = [self.mcs_path, "-removeDup", "-thin", self.clean_mch_file, self.final_mch_file]
+        proc = subprocess.Popen(command)
+        proc.communicate()
+
+        if not os.path.isfile(self.final_mch_file):
+            raise RuntimeError("Error, final mch file not created correctly.")
+
+        if not self.coreclr_args.skip_cleanup:
+            os.remove(self.clean_mch_file)
+            self.clean_mch_file = None
+        
+    def __create_toc__(self):
+        """ Create a TOC file
+        
+        Notes:
+            <mcl> -toc <s_finalMchFile>
+        """
+
+        command = [self.mcs_path, "-toc", self.final_mch_file]
+        proc = subprocess.Popen(command)
+        proc.communicate()
+
+        if not os.path.isfile(self.toc_file):
+            raise RuntimeError("Error, toc file not created correctly.")
+
+    def __verify_final_mch__(self):
+        """ Verify the resulting MCH file is error-free when running SuperPMI against it with the same JIT used for collection.
+        
+        Notes:
+            <superPmiPath> -p -f <s_finalFailMclFile> <s_finalMchFile> <jitPath>
+        """
+
+        spmi_replay = SuperPMIReplay(self.coreclr_args, self.final_mch_file, self.jit_path)
+        passed = spmi_replay.replay()
+
+        if not passed:
+            raise RuntimeError("Error unclean replay.")
+
+################################################################################
+# SuperPMI Replay
+################################################################################
+
+class SuperPMIReplay:
+    """ SuperPMI Replay class
+
+    Notes:
+        The object is responsible for replaying the mch final given to the
+        instance of the class
+    """
+
+    def __init__(self, coreclr_args, mch_file, jit_path):
+        """ Constructor
+
+        Args:
+            args (CoreclrArguments) : parsed args
+            mch_file (str)          : final mch file from the collection
+            jit_path (str)          : path to clrjit/libclrjit
+
+        """
+
+        self.jit_path = jit_path
+        self.mch_file = mch_file
+        self.superpmi_path = os.path.join(coreclr_args.core_root, "superpmi")
+
+        self.coreclr_args = coreclr_args
+
+    ############################################################################
+    # Instance Methods
+    ############################################################################
+
+    def replay(self):
+        """ Replay the given SuperPMI collection
+
+        Returns:
+            sucessful_replay (bool)
+        """
+
+        return_code = False
+
+        # Possible return codes from SuperPMI
+        #
+        # 0  : success
+        # -1 : general fatal error (e.g., failed to initialize, failed to read files)
+        # -2 : JIT failed to initialize
+        # 1  : there were compilation failures
+        # 2  : there were assembly diffs
+        
+        with TempDir() as temp_location:
+            print("Starting SuperPMI replay.")
+            print("")
+            print("Temp Location: {}".format(temp_location))
+            print("")
+
+            self.fail_mcl_file = os.path.join(temp_location, "fail.mcl")
+
+            # TODO: add aljit support
+            #
+            # Set: -jitoption force AltJit=* -jitoption force AltJitNgen=*
+            force_altjit_options = [
+                "-jitoption",
+                "force",
+                "AltJit=",
+                "-jitoption",
+                "force",
+                "AltJitNgen="
+            ]
+
+            flags = [
+                "-p", # Parallel
+                "-f", # Failing mc List
+                self.fail_mcl_file,
+                "-r", # Repro name, create .mc repro files
+                os.path.join(temp_location, "repro")
+            ]
+
+            flags += force_altjit_options
+
+            if self.coreclr_args.break_on_assert:
+                flags += [
+                    "-boa" # break on assert
+                ]
+            
+            if self.coreclr_args.break_on_error:
+                flags += [
+                    "-boe" # break on error
+                ]
+
+            if self.coreclr_args.log_file != None:
+                flags += [
+                    "-w",
+                    self.coreclr_args.log_file
+                ]
+
+            command = [self.superpmi_path] + flags + [self.jit_path, self.mch_file]
+
+            print("Invoking: " + " ".join(command))
+            proc = subprocess.Popen(command)
+            proc.communicate()
+
+            return_code = proc.returncode
+
+            if return_code == 0:
+                print("Clean SuperPMI Replay")
+                return_code = True
+
+            if os.path.isfile(self.fail_mcl_file) and os.stat(self.fail_mcl_file).st_size != 0:
+                # Unclean replay.
+                #
+                # Save the contents of the fail.mcl file to dig into failures.
+
+                assert(return_code != 0)
+
+                if return_code == -1:
+                    print("General fatal error.")
+                elif return_code == -2:
+                    print("Jit failed to initialize.")
+                elif return_code == 1:
+                    print("Complition failures.")
+                else:
+                    print("Unknown error code.")
+
+                self.fail_mcl_contents = None
+                with open(self.fail_mcl_file) as file_handle:
+                    self.fail_mcl_contents = file_handle.read()
+
+                # If there are any .mc files, drop them into bin/repro/<host_os>.<arch>.<build_type>/*.mc
+                mc_files = [os.path.join(temp_location, item) for item in os.listdir(temp_location) if item.endswith(".mc")]
+
+                if len(mc_files) > 0:
+                    repro_location = os.path.join(self.coreclr_args.coreclr_repo_location, "bin", "repro", "{}.{}.{}".format(self.coreclr_args.host_os, self.coreclr_args.arch, self.coreclr_args.build_type))
+
+                    # Delete existing repro location
+                    if os.path.isdir(repro_location):
+                        shutil.rmtree(repro_location)
+
+                    assert(not os.path.isdir(repro_location))
+
+                    os.makedirs(repro_location)
+                    
+                    repro_files = []
+                    for item in mc_files:
+                        repro_files.append(os.path.join(repro_location, os.path.basename(item)))
+                        shutil.copy2(item, repro_location)
+
+                    print("")
+                    print("Repro .mc files:")
+                    print("")
+
+                    for item in repro_files:
+                        print(item)
+                    
+                    print("")
+
+                    print("To run an specific failure:")
+                    print("")
+                    print("<SuperPMI_path>/SuperPMI <core_root|product_dir>/clrjit.dll|libclrjit.so|libclrjit.dylib <<coreclr_path>/bin/repro/<host_os>.<arch>.<build_type>/1xxxx.mc")
+                    print("")
+
+                else:
+                    print(self.fail_mcl_contents)
+
+            if not self.coreclr_args.skip_cleanup:
+                if os.path.isfile(self.fail_mcl_file):
+                    os.remove(self.fail_mcl_file)
+                    self.fail_mcl_file = None
+
+                return_code == False
+
+        return return_code
+
+################################################################################
+# SuperPMI Replay/AsmDiffs
+################################################################################
+
+class SuperPMIReplayAsmDiffs:
+    """ SuperPMI Replay AsmDiffs class
+
+    Notes:
+        The object is responsible for replaying the mch final given to the
+        instance of the class and doing diffs on the two passed jits.
+    """
+
+    def __init__(self, coreclr_args, mch_file, base_jit_path, diff_jit_path):
+        """ Constructor
+
+        Args:
+            args (CoreclrArguments) : parsed args
+            mch_file (str)          : final mch file from the collection
+            base_jit_path (str)     : path to clrjit/libclrjit
+            diff_jit_path (str)     : path to clrjit/libclrjit
+
+        """
+
+        self.base_jit_path = base_jit_path
+        self.diff_jit_path = diff_jit_path
+
+        self.mch_file = mch_file
+        self.superpmi_path = os.path.join(coreclr_args.core_root, "superpmi")
+
+        self.coreclr_args = coreclr_args
+
+    ############################################################################
+    # Instance Methods
+    ############################################################################
+
+    def replay_with_asm_diffs(self):
+        """ Replay the given SuperPMI collection
+
+        Returns:
+            sucessful_replay (bool)
+        """
+
+        return_code = False
+
+        # Possible return codes from SuperPMI
+        #
+        # 0  : success
+        # -1 : general fatal error (e.g., failed to initialize, failed to read files)
+        # -2 : JIT failed to initialize
+        # 1  : there were compilation failures
+        # 2  : there were assembly diffs
+        
+        with TempDir() as temp_location:
+            print("Starting SuperPMI AsmDiffs.")
+            print("")
+            print("Temp Location: {}".format(temp_location))
+            print("")
+
+            self.fail_mcl_file = os.path.join(temp_location, "fail.mcl")
+            self.diff_mcl_file = os.path.join(temp_location, "diff.mcl")
+
+            # TODO: add aljit support
+            #
+            # Set: -jitoption force AltJit=* -jitoption force AltJitNgen=*
+            force_altjit_options = [
+                "-jitoption",
+                "force",
+                "AltJit=",
+                "-jitoption",
+                "force",
+                "AltJitNgen=",
+                "-jit2option",
+                "force",
+                "AltJit=",
+                "-jit2option",
+                "force",
+                "AltJitNgen="
+            ]
+
+            flags = [
+                "-a", # Asm diffs
+                "-p", # Parallel
+                "-f", # Failing mc List
+                self.fail_mcl_file,
+                "-diffMCList", # Create all of the diffs in an mcl file
+                self.diff_mcl_file,
+                "-r", # Repro name, create .mc repro files
+                os.path.join(temp_location, "repro")
+            ]
+
+            flags += force_altjit_options
+
+            if self.coreclr_args.break_on_assert:
+                flags += [
+                    "-boa" # break on assert
+                ]
+            
+            if self.coreclr_args.break_on_error:
+                flags += [
+                    "-boe" # break on error
+                ]
+
+            if self.coreclr_args.log_file != None:
+                flags += [
+                    "-w",
+                    self.coreclr_args.log_file
+                ]
+
+            if not self.coreclr_args.diff_with_code_only:
+                # Change the working directory to the core root we will call SuperPMI from.
+                # This is done to allow libcoredistools to be loaded correctly on unix
+                # as the loadlibrary path will be relative to the current directory.
+                with ChangeDir(self.coreclr_args.core_root) as dir:
+                    command = [self.superpmi_path] + flags + [self.base_jit_path, self.diff_jit_path, self.mch_file]
+
+                    print("Invoking: " + " ".join(command))
+                    proc = subprocess.Popen(command)
+                    proc.communicate()
+
+                return_code = proc.returncode
+
+                if return_code == 0:
+                    print("Clean SuperPMI Replay")
+
+            else:
+                return_code = 2
+
+            if os.path.isfile(self.fail_mcl_file) and os.stat(self.fail_mcl_file).st_size != 0:
+                # Unclean replay.
+                #
+                # Save the contents of the fail.mcl file to dig into failures.
+
+                assert(return_code != 0)
+
+                if return_code == -1:
+                    print("General fatal error.")
+                elif return_code == -2:
+                    print("Jit failed to initialize.")
+                elif return_code == 1:
+                    print("Complition failures.")
+                elif return_code == 139 and self.coreclr_args != "Windows_NT":
+                    print("Fatal error, SuperPMI has returned SIG_SEV (segmentation fault).")
+                else:
+                    print("Unknown error code.")
+
+                self.fail_mcl_contents = None
+                mcl_lines = []
+                with open(self.fail_mcl_file) as file_handle:
+                    mcl_lines = file_handle.readlines()
+                    mcl_lines = [item.strip() for item in mcl_lines]
+                    self.fail_mcl_contents = os.linesep.join(mcl_lines)
+
+                # If there are any .mc files, drop them into bin/repro/<host_os>.<arch>.<build_type>/*.mc
+                mc_files = [os.path.join(temp_location, item) for item in os.listdir(temp_location) if item.endswith(".mc")]
+
+                if len(mc_files) > 0:
+                    repro_location = os.path.join(self.coreclr_args.coreclr_repo_location, "bin", "repro", "{}.{}.{}".format(self.coreclr_args.host_os, self.coreclr_args.arch, self.coreclr_args.build_type))
+
+                    # Delete existing repro location
+                    if os.path.isdir(repro_location):
+                        shutil.rmtree(repro_location)
+
+                    assert(not os.path.isdir(repro_location))
+
+                    os.makedirs(repro_location)
+                    
+                    repro_files = []
+                    for item in mc_files:
+                        repro_files.append(os.path.join(repro_location, os.path.basename(item)))
+                        shutil.copy2(item, repro_location)
+
+                    print("")
+                    print("Repro .mc files:")
+                    print("")
+
+                    for item in repro_files:
+                        print(item)
+                    
+                    print("")
+
+                    print("To run an specific failure:")
+                    print("")
+                    print("<SuperPMI_path>/SuperPMI <core_root|product_dir>/clrjit.dll|libclrjit.so|libclrjit.dylib <<coreclr_path>/bin/repro/<host_os>.<arch>.<build_type>/1xxxx.mc")
+                    print("")
+
+                print(self.fail_mcl_contents)
+
+            # There were diffs. Go through each method that created diffs and
+            # create a base/diff asm file with diffable asm. In addition, create
+            # a standalone .mc for easy iteration.
+            if os.path.isfile(self.diff_mcl_file) and os.stat(self.diff_mcl_file).st_size != 0 or self.coreclr_args.diff_with_code_only:
+                # AsmDiffs.
+                #
+                # Save the contents of the fail.mcl file to dig into failures.
+                
+                assert(return_code != 0)
+
+                if return_code == -1:
+                    print("General fatal error.")
+                elif return_code == -2:
+                    print("Jit failed to initialize.")
+                elif return_code == 1:
+                    print("Complition failures.")
+                elif return_code == 139 and self.coreclr_args != "Windows_NT":
+                    print("Fatal error, SuperPMI has returned SIG_SEV (segmentation fault).")
+                else:
+                    print("Unknown error code.")
+
+                if not self.coreclr_args.diff_with_code_only:
+                    self.diff_mcl_contents = None
+                    with open(self.diff_mcl_file) as file_handle:
+                        mcl_lines = file_handle.readlines()
+                        mcl_lines = [item.strip() for item in mcl_lines]
+                        self.diff_mcl_contents = mcl_lines
+
+                base_asm_location = os.path.join(self.coreclr_args.bin_location, "asm", "base")
+                diff_asm_location = os.path.join(self.coreclr_args.bin_location, "asm", "diff")
+
+                base_dump_location = os.path.join(self.coreclr_args.bin_location, "jit_dump", "base")
+                diff_dump_location = os.path.join(self.coreclr_args.bin_location, "jit_dump", "diff")
+
+                if not self.coreclr_args.diff_with_code_only:
+                    # Delete the old asm.
+                    
+                    # Create a diff and baseline directory
+                    if os.path.isdir(base_asm_location):
+                        shutil.rmtree(base_asm_location)
+                    if os.path.isdir(diff_asm_location):
+                        shutil.rmtree(diff_asm_location)
+
+                    os.makedirs(base_asm_location)
+                    os.makedirs(diff_asm_location)
+
+                    assert(os.path.isdir(base_asm_location))
+                    assert(os.path.isdir(diff_asm_location))
+
+                    assert(len(os.listdir(base_asm_location)) == 0)
+                    assert(len(os.listdir(diff_asm_location)) == 0)
+
+                    if self.coreclr_args.diff_jit_dump:
+                        # Create a diff and baseline directory for jit_dumps
+                        if os.path.isdir(base_dump_location):
+                            shutil.rmtree(base_dump_location)
+                        if os.path.isdir(diff_dump_location):
+                            shutil.rmtree(diff_dump_location)
+
+                        os.makedirs(base_dump_location)
+                        os.makedirs(diff_dump_location)
+
+                        assert(os.path.isdir(base_dump_location))
+                        assert(os.path.isdir(diff_dump_location))
+
+                        assert(len(os.listdir(base_dump_location)) == 0)
+                        assert(len(os.listdir(diff_dump_location)) == 0)
+
+                text_differences = []
+                jit_dump_differences = []
+
+                if not self.coreclr_args.diff_with_code_only:
+                    for item in self.diff_mcl_contents:
+                        # Setup to call SuperPMI for both the diff jit and the base
+                        # jit
+
+                        # TODO: add aljit support
+                        #
+                        # Set: -jitoption force AltJit=* -jitoption force AltJitNgen=*
+                        force_altjit_options = [
+                            "-jitoption",
+                            "force",
+                            "AltJit=",
+                            "-jitoption",
+                            "force",
+                            "AltJitNgen="
+                        ]
+
+                        flags = [
+                            "-c",
+                            item,
+                            "-v",
+                            "q" # only log from the jit.
+                        ]
+
+                        flags += force_altjit_options
+                        
+                        asm_env = os.environ.copy()
+                        asm_env["COMPlus_JitDisasm"] = "*"
+                        asm_env["COMPlus_JitUnwindDump"] = "*"
+                        asm_env["COMPlus_JitEHDump"] = "*"
+                        asm_env["COMPlus_JitDiffableDasm"] = "1"
+                        asm_env["COMPlus_NgenDisasm"] = "*"
+                        asm_env["COMPlus_NgenDump"] = "*"
+                        asm_env["COMPlus_NgenUnwindDump"] = "*"
+                        asm_env["COMPlus_NgenEHDump"] = "*"
+                        asm_env["COMPlus_JitEnableNoWayAssert"] = "1"
+                        asm_env["COMPlus_JitNoForceFallback"] = "1"
+                        asm_env["COMPlus_JitRequired"] = "1"
+
+                        jit_dump_env = os.environ.copy()
+                        jit_dump_env["COMPlus_JitEnableNoWayAssert"] = "1"
+                        jit_dump_env["COMPlus_JitNoForceFallback"] = "1"
+                        jit_dump_env["COMPlus_JitRequired"] = "1"
+                        jit_dump_env["COMPlus_JitDump"] = "*"
+
+                        # Change the working directory to the core root we will call SuperPMI from.
+                        # This is done to allow libcoredistools to be loaded correctly on unix
+                        # as the loadlibrary path will be relative to the current directory.
+                        with ChangeDir(self.coreclr_args.core_root) as dir:
+                            command = [self.superpmi_path] + flags + [self.base_jit_path, self.mch_file]
+
+                            # Generate diff and base asm
+                            base_txt = None
+                            diff_txt = None
+
+                            with open(os.path.join(base_asm_location, "{}.asm".format(item)), 'w') as file_handle:
+                                print("Invoking: " + " ".join(command))
+                                proc = subprocess.Popen(command, env=asm_env, stdout=file_handle)
+                                proc.communicate()
+
+                            command = [self.superpmi_path] + flags + [self.diff_jit_path, self.mch_file]
+
+                            with open(os.path.join(diff_asm_location, "{}.asm".format(item)), 'w') as file_handle:
+                                print("Invoking: " + " ".join(command))
+                                proc = subprocess.Popen(command, env=asm_env, stdout=file_handle)
+                                proc.communicate()
+
+                            with open(os.path.join(base_asm_location, "{}.asm".format(item))) as file_handle:
+                                base_txt = file_handle.read()
+
+                            with open(os.path.join(diff_asm_location, "{}.asm".format(item))) as file_handle:
+                                diff_txt = file_handle.read()
+
+                            if base_txt != diff_txt:
+                                text_differences.append(item)
+                            
+                            if self.coreclr_args.diff_jit_dump:
+                                # Generate jit dumps
+                                base_txt = None
+                                diff_txt = None
+
+                                command = [self.superpmi_path] + flags + [self.base_jit_path, self.mch_file]
+
+                                with open(os.path.join(base_dump_location, "{}.txt".format(item)), 'w') as file_handle:
+                                    print("Invoking: " + " ".join(command))
+                                    proc = subprocess.Popen(command, env=jit_dump_env, stdout=file_handle)
+                                    proc.communicate()
+
+                                command = [self.superpmi_path] + flags + [self.diff_jit_path, self.mch_file]
+
+                                with open(os.path.join(diff_dump_location, "{}.txt".format(item)), 'w') as file_handle:
+                                    print("Invoking: " + " ".join(command))
+                                    proc = subprocess.Popen(command, env=jit_dump_env, stdout=file_handle)
+                                    proc.communicate()
+
+                                with open(os.path.join(base_dump_location, "{}.txt".format(item))) as file_handle:
+                                    base_txt = file_handle.read()
+
+                                with open(os.path.join(diff_dump_location, "{}.txt".format(item))) as file_handle:
+                                    diff_txt = file_handle.read()
+
+                                if base_txt != diff_txt:
+                                    jit_dump_differences.append(item)
+
+                else:
+                    # We have already generated asm under <coreclr_bin_path>/asm/base and <coreclr_bin_path>/asm/diff
+                    for item in os.listdir(base_asm_location):
+                        base_asm_file = os.path.join(base_asm_location, item)
+                        diff_asm_file = os.path.join(diff_asm_location, item)
+
+                        base_txt = None
+                        diff_txt = None
+
+                        # Every file should have a diff asm file.
+                        assert os.path.isfile(diff_asm_file)
+
+                        with open(base_asm_file) as file_handle:
+                            base_txt = file_handle.read()
+
+                        with open(diff_asm_file) as file_handle:
+                            diff_txt = file_handle.read()
+
+                        if base_txt != diff_txt:
+                            text_differences.append(item[:-4])
+
+                    if self.coreclr_args.diff_jit_dump:
+                        for item in os.listdir(base_dump_location):
+                            base_dump_file = os.path.join(base_dump_location, item)
+                            diff_dump_file = os.path.join(diff_dump_location, item)
+
+                            base_txt = None
+                            diff_txt = None
+
+                            # Every file should have a diff asm file.
+                            assert os.path.isfile(diff_dump_file)
+
+                            with open(base_dump_file) as file_handle:
+                                base_txt = file_handle.read()
+
+                            with open(diff_dump_file) as file_handle:
+                                diff_txt = file_handle.read()
+
+                            if base_txt != diff_txt:
+                                jit_dump_differences.append(item[:-4])
+
+                if not self.coreclr_args.diff_with_code_only:
+                    print("Differences found, to replay SuperPMI use <path_to_SuperPMI> -jitoption force AltJit= -jitoption force AltJitNgen= -c ### <path_to_jit> <path_to_mcl>")
+                    print("")
+                    print("Binary differences found with superpmi -a")
+                    print("")
+                    print("Method numbers with binary differences:")
+                    print(self.diff_mcl_contents)
+                    print("")
+
+                if len(text_differences) > 0:
+                    print("Textual differences found, the asm is located under %s and %s" % (base_asm_location, diff_asm_location))
+                    print("")
+                    print("Method numbers with textual differences:")
+                    
+                    print(text_differences)
+
+                    if self.coreclr_args.diff_with_code and not self.coreclr_args.diff_jit_dump_only:
+                        batch_command = ["cmd", "/c"] if platform.system() == "Windows" else []
+                        for index, item in enumerate(text_differences):
+                            command = batch_command + [
+                                "code",
+                                "-d",
+                                os.path.join(base_asm_location, "{}.asm".format(item)),
+                                os.path.join(diff_asm_location, "{}.asm".format(item))
+                            ]
+                            print("Invoking: " + " ".join(command))
+                            proc = subprocess.Popen(command)
+
+                            if index > 5:
+                                break
+
+                    print("")
+                else:
+                    print("No textual differences. Is this an issue with libcoredistools?")
+
+                if len(jit_dump_differences) > 0:
+                    print("Diffs found in the JitDump generated. These files are located under <coreclr_dir>/bin/jit_dump/base and <coreclr_dir>/bin/jit_dump/diff")
+                    print("")
+                    print("Method numbers with textual differences:")
+
+                    print(jit_dump_differences)
+
+                    if self.coreclr_args.diff_with_code:
+                        batch_command = ["cmd", "/c"] if platform.system() == "Windows" else []
+                        for index, item in enumerate(text_differences):
+                            command = batch_command + [
+                                "code",
+                                "-d",
+                                os.path.join(base_dump_location, "{}.txt".format(item)),
+                                os.path.join(diff_dump_location, "{}.txt".format(item))
+                            ]
+                            print("Invoking: " + " ".join(command))
+                            proc = subprocess.Popen(command)
+
+                            if index > 5:
+                                break
+
+                    print("")
+
+            if not self.coreclr_args.skip_cleanup:
+                if os.path.isfile(self.fail_mcl_file):
+                    os.remove(self.fail_mcl_file)
+                    self.fail_mcl_file = None
+
+        return return_code
+
+################################################################################
+# Helper Methods
+################################################################################
+
+def determine_coredis_tools(coreclr_args):
+    """ Determine the coredistools location
+
+    Args:
+        coreclr_args (CoreclrArguments) : parsed args
+
+    Returns:
+        coredistools_location (str)     : path of libcoredistools.dylib|so|dll
+
+    Notes:
+        If unable to find libcoredist tools, download it from azure storage.
+    """
+
+    coredistools_dll_name = None
+    if coreclr_args.host_os.lower() == "osx":
+        coredistools_dll_name = "libcoredistools.dylib"
+    elif coreclr_args.host_os.lower() == "linux":
+        coredistools_dll_name = "libcoredistools.so"
+    elif coreclr_args.host_os.lower() == "windows_nt":
+        coredistools_dll_name = "coredistools.dll"
+    else:
+        raise RuntimeError("Unknown host os: {}").format(coreclr_args.host_os)
+
+    coredistools_uri = "https://clrjit.blob.core.windows.net/superpmi/libcoredistools/{}-{}/{}".format(coreclr_args.host_os.lower(), coreclr_args.arch.lower(), coredistools_dll_name)
+
+    coredistools_location = os.path.join(coreclr_args.core_root, coredistools_dll_name)
+    if not os.path.isfile(coredistools_location):
+        urlretrieve = urllib.urlretrieve if sys.version_info.major < 3 else urllib.request.urlretrieve
+        urlretrieve(coredistools_uri, coredistools_location)
+
+    assert os.path.isfile(coredistools_location)
+    return coredistools_location
+
+def determine_jit_name(coreclr_args):
+    """ Determine the jit based on the os
+
+    Args:
+        coreclr_args (CoreclrArguments): parsed args
+    
+    Return:
+        jit_name(str) : name of the jit for this os
+    """
+
+    if coreclr_args.host_os == "OSX":
+        return "libclrjit.dylib"
+    elif coreclr_args.host_os == "Linux":
+        return "libclrjit.so"
+    elif coreclr_args.host_os == "Windows_NT":
+        return "clrjit.dll"
+    else:
+        raise RuntimeError("Unknown os.")
+
+def print_platform_specific_environment_vars(coreclr_args, var, value):
+    """ Print environment variables as set {}={} or export {}={}
+
+    Args:
+        coreclr_args (CoreclrArguments): parsed args
+        var   (str): variable to set
+        value (str): value being set.
+    """
+
+    if coreclr_args.host_os == "Windows_NT":
+        print("set {}={}".format(var, value))
+    else:
+        print("export {}={}".format(var, value))
+
+def setup_args(args):
+    """ Setup the args for SuperPMI to use.
+
+    Args:
+        args (ArgParse): args parsed by arg parser
+    
+    Returns:
+        args (CoreclrArguments)
+
+    """
+    coreclr_args = CoreclrArguments(args, require_built_core_root=True, require_built_product_dir=False, require_built_test_dir=False, default_build_type="Checked")
+
+    coreclr_args.verify(args,
+                        "skip_cleanup",
+                        lambda unused: True,
+                        "Unable to set skip_cleanup")
+
+    coreclr_args.verify(args,
+                        "mode",
+                        lambda mode: mode in ["collect", "replay", "asmdiffs"],
+                        'Incorrect mode passed, please choose from ["collect", "replay", "asmdiffs"]')
+
+    coreclr_args.verify(args,
+                        "run_from_coreclr_dir",
+                        lambda unused: True,
+                        "Error setting run_from_coreclr_dir")
+
+    default_coreclr_bin_mch_location = os.path.join(coreclr_args.bin_location, "mch", "{}.{}.{}".format(coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type))
+
+    def setup_mch_arg(arg):
+        default_mch_location = os.path.join(coreclr_args.bin_location, "mch", "{}.{}.{}".format(coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type), "{}.{}.{}.mch".format(coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type))
+
+        if os.path.isfile(default_mch_location) and not args.force_download:
+            return default_mch_location
+
+        # Download the mch
+        else:
+            uri_mch_location = "https://clrjit.blob.core.windows.net/superpmi/{}/{}/{}/{}.{}.{}.mch.zip".format(coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type, coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type)
+
+            with TempDir() as temp_location:
+                urlretrieve = urllib.urlretrieve if sys.version_info.major < 3 else urllib.request.urlretrieve
+                zipfilename = os.path.join(temp_location, "temp.zip")
+                urlretrieve(uri_mch_location, zipfilename)
+
+                default_mch_dir = os.path.join(coreclr_args.bin_location, "mch", "{}.{}.{}".format(coreclr_args.host_os, coreclr_args.arch, coreclr_args.build_type))
+
+                # Clean all the files out of the default location.
+                default_mch_dir_items = [os.path.join(default_mch_dir, item) for item in os.listdir(default_mch_dir)]
+                for item in default_mch_dir_items:
+                    if os.path.isdir(item):
+                        shutil.rmtree(item)
+                    else:
+                        os.remove(item)
+
+                if not os.path.isdir(default_mch_dir):
+                    os.makedirs(default_mch_dir)
+
+                with zipfile.ZipFile(zipfilename, "r") as file_handle:
+                    file_handle.extractall(temp_location)
+
+                items = [os.path.join(temp_location, item) for item in os.listdir(temp_location) if not item.endswith(".zip")]
+
+                for item in items:
+                    shutil.copy2(item, default_mch_dir)
+
+            return default_mch_location
+
+    if not os.path.isdir(default_coreclr_bin_mch_location):
+        os.makedirs(default_coreclr_bin_mch_location)
+
+    coreclr_args.verify(default_coreclr_bin_mch_location,
+                        "default_coreclr_bin_mch_location",
+                        lambda unused: True,
+                        "Error setting default_coreclr_bin_mch_location")
+
+    if coreclr_args.mode == "collect":
+        coreclr_args.verify(args,
+                            "collection_command",
+                            lambda command_list: len(command_list) == 1,
+                            "Unable to find script.",
+                            modify_arg=lambda arg: arg[0],
+                            modify_after_validation=True)
+        coreclr_args.verify(args,
+                            "collection_args",
+                            lambda unused: True,
+                            "Unable to set collection_args",
+                            modify_arg=lambda collection_args: collection_args[0].split(" ") if collection_args is not None else collection_args)
+
+        coreclr_args.verify(args,
+                            "output_mch_path",
+                            lambda unused: True,
+                            "Unable to set output_mch_path")
+
+        coreclr_args.verify(args,
+                            "skip_collect_mc_files",
+                            lambda unused: True,
+                            "Unable to set skip_collect_mc_files")
+
+        coreclr_args.verify(args,
+                            "existing_temp_dir",
+                            lambda unused: True,
+                            "Unable to set existing_temp_dir.")
+
+        coreclr_args.verify(args,
+                            "assume_unclean_mch",
+                            lambda unused: True,
+                            "Unable to set assume_unclean_mch.")
+
+        coreclr_args.verify(args,
+                            "has_run_collection_command",
+                            lambda unused: True,
+                            "Unable to set has_run_collection_command.")
+
+        coreclr_args.verify(args,
+                            "has_merged_mch",
+                            lambda unused: True,
+                            "Unable to set has_merged_mch.")
+
+        coreclr_args.verify(args,
+                            "has_verified_clean_mch",
+                            lambda unused: True,
+                            "Unable to set has_verified_clean_mch.")
+
+        coreclr_args.verify(args,
+                            "break_on_assert",
+                            lambda unused: True,
+                            "Unable to set break_on_assert")
+
+        coreclr_args.verify(args,
+                            "break_on_error",
+                            lambda unused: True,
+                            "Unable to set break_on_error")
+
+        coreclr_args.verify(args,
+                            "use_zapdisable",
+                            lambda unused: True,
+                            "Unable to set use_zapdisable")
+
+        jit_location = os.path.join(coreclr_args.core_root, determine_jit_name(coreclr_args))
+        assert(os.path.isfile(jit_location))
+    
+    elif coreclr_args.mode == "replay":
+        coreclr_args.verify(args,
+                            "mch_file",
+                            lambda mch_file: os.path.isfile(mch_file),
+                            lambda mch_file: "Incorrect file path to mch_file: {}".format(mch_file),
+                            modify_arg=lambda arg: arg[0] if arg is not None else setup_mch_arg(arg))
+        
+        coreclr_args.verify(args,
+                            "jit_path",
+                            lambda jit_path: os.path.isfile(jit_path),
+                            "Unable to set jit_path",
+                            modify_arg=lambda arg: arg[0])
+
+        coreclr_args.verify(args,
+                            "log_file",
+                            lambda unused: True,
+                            "Unable to set log_file.")
+
+        coreclr_args.verify(args,
+                            "break_on_assert",
+                            lambda unused: True,
+                            "Unable to set break_on_assert")
+
+        coreclr_args.verify(args,
+                            "break_on_error",
+                            lambda unused: True,
+                            "Unable to set break_on_error")
+
+        standard_location = False
+        if coreclr_args.bin_location.lower() in coreclr_args.jit_path.lower():
+            standard_location = True
+
+        determined_arch = None
+        determined_build_type = None
+        if standard_location:
+            standard_location_split = coreclr_args.jit_path.split(coreclr_args.bin_location)
+
+            assert(coreclr_args.host_os in standard_location_split[1])
+            specialized_path = standard_location_split[1].split(coreclr_args.host_os)
+
+            specialized_path = specialized_path[1].split("/")[0]
+
+            determined_split = specialized_path.split(".")
+
+            determined_arch = determined_split[1]
+            determined_build_type = determined_split[2]
+
+        # Make a more intelligent decision about the arch and build type
+        # based on the path of the jit passed
+        if standard_location and not coreclr_args.build_type in coreclr_args.jit_path:
+            coreclr_args.verify(determined_arch.lower(),
+                                "arch",
+                                lambda unused: True,
+                                "Unable to set arch")
+            
+            coreclr_args.verify(determined_build_type,
+                                "build_type",
+                                coreclr_args.check_build_type,
+                                "Invalid build_type")
+
+        coreclr_args.verify(args,
+                            "mch_file",
+                            lambda mch_file: os.path.isfile(mch_file),
+                            lambda mch_file: "Incorrect file path to mch_file: {}".format(mch_file),
+                            modify_arg=lambda arg: arg[0] if arg is not None else setup_mch_arg(arg))
+
+    elif coreclr_args.mode == "asmdiffs":
+        coreclr_args.verify(args,
+                            "base_jit_path",
+                            lambda unused: True,
+                            "Unable to set base_jit_path",
+                            modify_arg=lambda arg: arg[0])
+
+        coreclr_args.verify(args,
+                            "diff_jit_path",
+                            lambda jit_path: True,
+                            "Unable to set base_jit_path",
+                            modify_arg=lambda arg: arg[0])
+
+        coreclr_args.verify(args,
+                            "log_file",
+                            lambda unused: True,
+                            "Unable to set log_file.")
+
+        coreclr_args.verify(args,
+                            "break_on_assert",
+                            lambda unused: True,
+                            "Unable to set break_on_assert")
+
+        coreclr_args.verify(args,
+                            "break_on_error",
+                            lambda unused: True,
+                            "Unable to set break_on_error")
+
+        coreclr_args.verify(args,
+                            "diff_with_code",
+                            lambda unused: True,
+                            "Unable to set diff_with_code.")
+
+        coreclr_args.verify(args,
+                            "diff_with_code_only",
+                            lambda unused: True,
+                            "Unable to set diff_with_code_only.")
+
+        if coreclr_args.diff_with_code_only:
+            # Set diff with code if we are not running SuperPMI to regenerate diffs.
+            # This avoids having to re-run generating asm diffs.
+            coreclr_args.verify(True,
+                                "diff_with_code",
+                                lambda unused: True,
+                                "Unable to set diff_with_code.")
+
+        coreclr_args.verify(args,
+                            "diff_jit_dump",
+                            lambda unused: True,
+                            "Unable to set diff_jit_dump.")
+
+        coreclr_args.verify(args,
+                            "diff_jit_dump_only",
+                            lambda unused: True,
+                            "Unable to set diff_jit_dump_only.")
+
+        if coreclr_args.diff_jit_dump_only:
+            coreclr_args.verify(True,
+                                "diff_jit_dump",
+                                lambda unused: True,
+                                "Unable to set diff_jit_dump.")
+
+        standard_location = False
+        if coreclr_args.bin_location.lower() in coreclr_args.base_jit_path.lower():
+            standard_location = True
+
+        determined_arch = None
+        determined_build_type = None
+        if standard_location:
+            standard_location_split = coreclr_args.base_jit_path.split(coreclr_args.bin_location)
+
+            assert(coreclr_args.host_os in standard_location_split[1])
+            specialized_path = standard_location_split[1].split(coreclr_args.host_os)
+
+            specialized_path = specialized_path[1].split("/")[0]
+
+            determined_split = specialized_path.split(".")
+
+            determined_arch = determined_split[1]
+            determined_build_type = determined_split[2]
+
+        # Make a more intelligent decision about the arch and build type
+        # based on the path of the jit passed
+        if standard_location and not coreclr_args.build_type in coreclr_args.base_jit_path:
+            coreclr_args.verify(determined_build_type,
+                                "build_type",
+                                coreclr_args.check_build_type,
+                                "Invalid build_type")
+
+        if standard_location and not coreclr_args.arch in coreclr_args.base_jit_path:
+            coreclr_args.verify(determined_arch.lower(),
+                                "arch",
+                                lambda unused: True,
+                                "Unable to set arch")
+
+        coreclr_args.verify(determine_coredis_tools(coreclr_args),
+                            "coredistools_location",
+                            lambda coredistools_path: os.path.isfile(coredistools_path),
+                            "Unable to find coredistools.")
+
+        coreclr_args.verify(args,
+                            "mch_file",
+                            lambda mch_file: os.path.isfile(mch_file),
+                            lambda mch_file: "Incorrect file path to mch_file: {}".format(mch_file),
+                            modify_arg=lambda arg: arg[0] if arg is not None else setup_mch_arg(arg))
+    
+    return coreclr_args
+
+################################################################################
+# main
+################################################################################
+
+def main(args):
+    """ Main method
+    """
+
+    # Force tieried compilation off. It will effect both collection and replay
+    os.environ["COMPlus_TieredCompilation"] = "0"
+
+    coreclr_args = setup_args(args)
+    success = True
+
+    if coreclr_args.mode == "collect":
+        # Start a new SuperPMI Collection.
+
+        begin_time = datetime.datetime.now()
+
+        print("SuperPMI Collect")
+        print("------------------------------------------------------------")
+        print("Start time: {}".format(begin_time.strftime("%H:%M:%S")))
+
+        collection = SuperPMICollect(coreclr_args)
+        success = collection.collect()
+
+        print("Finished SuperPMI collect")
+
+        if coreclr_args.output_mch_path != None:
+            print("mch path: {}".format(coreclr_args.output_mch_path))
+
+        end_time = datetime.datetime.now()
+
+        print("Finish time: {}".format(end_time.strftime("%H:%M:%S")))
+
+    elif coreclr_args.mode == "replay":
+        # Start a new SuperPMI Replay
+
+        begin_time = datetime.datetime.now()
+
+        print("SuperPMI Replay")
+        print("------------------------------------------------------------")
+        print("Start time: {}".format(begin_time.strftime("%H:%M:%S")))
+
+        mch_file = coreclr_args.mch_file
+        jit_path = coreclr_args.jit_path
+
+        print("")
+
+        print("MCH Path: {}".format(mch_file))
+        print("Jit Path: {}".format(jit_path))
+
+        replay = SuperPMIReplay(coreclr_args, mch_file, jit_path)
+        success = replay.replay()
+
+        print("Finished SuperPMI replay")
+
+        end_time = datetime.datetime.now()
+
+        print("Finish time: {}".format(end_time.strftime("%H:%M:%S")))
+
+    elif coreclr_args.mode == "asmdiffs":
+        # Start a new SuperPMI Replay with AsmDiffs
+
+        begin_time = datetime.datetime.now()
+
+        print("SuperPMI Replay")
+        print("------------------------------------------------------------")
+        print("Start time: {}".format(begin_time.strftime("%H:%M:%S")))
+
+        mch_file = coreclr_args.mch_file
+        base_jit_path = coreclr_args.base_jit_path
+        diff_jit_path = coreclr_args.diff_jit_path
+
+        print("")
+
+        print("MCH Path: {}".format(mch_file))
+        print("Base Jit Path: {}".format(base_jit_path))
+        print("Diff Jit Path: {}".format(diff_jit_path))
+
+        asm_diffs = SuperPMIReplayAsmDiffs(coreclr_args, mch_file, base_jit_path, diff_jit_path)
+        success = asm_diffs.replay_with_asm_diffs()
+
+        print("Finished SuperPMI replay")
+
+        end_time = datetime.datetime.now()
+
+        print("Finish time: {}".format(end_time.strftime("%H:%M:%S")))
+    
+    return 0 if success else 1
+
+################################################################################
+# __main__
+################################################################################
+
+if __name__ == "__main__":
+    args = parser.parse_args()
+    sys.exit(main(args))