diff --git a/.travis.yml b/.travis.yml
index f08e7af8fe..ad653178a3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -151,7 +151,8 @@ script:
         BUILD_DIR=$TRAVIS_BUILD_DIR/build make -C analyzer \
           test_unit \
           test_functional \
-          test_tu_collector &&
+          test_tu_collector \
+          test_merge_clang_extdef_mappings &&
         if [[ "$TRAVIS_OS_NAME" = "linux" ]]; then
           make -C analyzer test_build_logger
         fi
diff --git a/Makefile b/Makefile
index b8c3d55969..425f194826 100644
--- a/Makefile
+++ b/Makefile
@@ -69,7 +69,17 @@ build_report_hash:
 package_report_hash: build_report_hash package_dir_structure
 	cp -r $(CC_TOOLS)/codechecker_report_hash/build/codechecker_report_hash/codechecker_report_hash $(CC_BUILD_LIB_DIR)
 
-package: package_dir_structure set_git_commit_template package_plist_to_html package_tu_collector package_report_converter package_report_hash
+build_merge_clang_extdef_mappings:
+	$(MAKE) -C $(CC_ANALYZER)/tools/merge_clang_extdef_mappings build
+
+package_merge_clang_extdef_mappings: build_merge_clang_extdef_mappings package_dir_structure
+	# Copy merge-clang-extdef-mappings files.
+	cp -r $(CC_ANALYZER)/tools/merge_clang_extdef_mappings/build/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings $(CC_BUILD_LIB_DIR) && \
+	chmod u+x $(CC_BUILD_LIB_DIR)/codechecker_merge_clang_extdef_mappings/cli.py && \
+	cd $(CC_BUILD_DIR) && \
+	ln -sf ../lib/python3/codechecker_merge_clang_extdef_mappings/cli.py bin/merge-clang-extdef-mappings
+
+package: package_dir_structure set_git_commit_template package_plist_to_html package_tu_collector package_report_converter package_report_hash package_merge_clang_extdef_mappings
 	BUILD_DIR=$(BUILD_DIR) BUILD_LOGGER_64_BIT_ONLY=$(BUILD_LOGGER_64_BIT_ONLY) $(MAKE) -C $(CC_ANALYZER) package_analyzer
 	BUILD_DIR=$(BUILD_DIR) $(MAKE) -C $(CC_WEB) package_web
 
diff --git a/analyzer/Makefile b/analyzer/Makefile
index f608677826..b0aa463f0b 100644
--- a/analyzer/Makefile
+++ b/analyzer/Makefile
@@ -54,12 +54,22 @@ package_tu_collector: build_tu_collector package_dir_structure
 	cd $(CC_BUILD_DIR) && \
 	ln -sf ../lib/python3/tu_collector/tu_collector.py bin/tu_collector
 
+build_merge_clang_extdef_mappings:
+	$(MAKE) -C tools/merge_clang_extdef_mappings build
+
+package_merge_clang_extdef_mappings: build_merge_clang_extdef_mappings package_dir_structure
+	# Copy plist-to-html files.
+	cp -r tools/merge_clang_extdef_mappings/build/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings $(CC_BUILD_LIB_DIR) && \
+	chmod u+x $(CC_BUILD_LIB_DIR)/codechecker_merge_clang_extdef_mappings/cli.py && \
+	cd $(CC_BUILD_DIR) && \
+	ln -sf ../lib/python3/codechecker_merge_clang_extdef_mappings/cli.py bin/merge-clang-extdef-mappings
+
 # This target should be used from the top level Makefile to build the package
 # together with the web part. This way we will not build plist-to-html
 # multiple times.
 package_analyzer: package_dir_structure
 
-package: package_plist_to_html package_tu_collector package_analyzer
+package: package_plist_to_html package_tu_collector package_analyzer package_merge_clang_extdef_mappings
 	# Copy libraries.
 	cp -r $(ROOT)/codechecker_common $(CC_BUILD_LIB_DIR) && \
 	cp -r $(CURRENT_DIR)/codechecker_analyzer $(CC_BUILD_LIB_DIR)
diff --git a/analyzer/codechecker_analyzer/analyzers/clangsa/ctu_manager.py b/analyzer/codechecker_analyzer/analyzers/clangsa/ctu_manager.py
index e4ac2d5bbd..1b480f0307 100644
--- a/analyzer/codechecker_analyzer/analyzers/clangsa/ctu_manager.py
+++ b/analyzer/codechecker_analyzer/analyzers/clangsa/ctu_manager.py
@@ -17,82 +17,33 @@
 
 from codechecker_common.logger import get_logger
 
+from merge_clang_extdef_mappings.merge import merge
+
 from .. import analyzer_base
 from . import ctu_triple_arch
 
 LOG = get_logger('analyzer')
 
 
-def generate_func_map_lines(fnmap_dir):
-    """ Iterate over all lines of input files in random order. """
-
-    files = glob.glob(os.path.join(fnmap_dir, '*'))
-    for filename in files:
-        with open(filename, 'r', encoding='utf-8',
-                  errors="ignore") as in_file:
-            for line in in_file:
-                yield line
-
-
-def create_global_ctu_function_map(func_map_lines):
-    """ Takes iterator of individual function maps and creates a global map
-    keeping only unique names. We leave conflicting names out of CTU.
-    A function map contains the id of a function (mangled name) and the
-    originating source (the corresponding AST file) name."""
-
-    mangled_to_asts = {}
-
-    for line in func_map_lines:
-        mangled_name, ast_file = line.strip().split(' ', 1)
-        # We collect all occurences of a function name into a list
-        if mangled_name not in mangled_to_asts:
-            mangled_to_asts[mangled_name] = {ast_file}
-        else:
-            mangled_to_asts[mangled_name].add(ast_file)
-
-    mangled_ast_pairs = []
-
-    for mangled_name, ast_files in mangled_to_asts.items():
-        if len(ast_files) == 1:
-            mangled_ast_pairs.append((mangled_name, ast_files.pop()))
-
-    return mangled_ast_pairs
-
-
-def write_global_map(ctu_dir, arch, ctu_func_map_file, mangled_ast_pairs):
-    """ Write (mangled function name, ast file) pairs into final file. """
-
-    extern_fns_map_file = os.path.join(ctu_dir, arch, ctu_func_map_file)
-    with open(extern_fns_map_file, 'w',
-              encoding='utf-8', errors='ignore') as out_file:
-        for mangled_name, ast_file in mangled_ast_pairs:
-            out_file.write('%s %s\n' % (mangled_name, ast_file))
+def merge_clang_extdef_mappings(ctu_dir, ctu_func_map_file,
+                                ctu_temp_fnmap_folder):
+    """ Merge individual function maps into a global one."""
 
+    triple_arches = glob.glob(os.path.join(ctu_dir, '*'))
+    for triple_path in triple_arches:
+        if not os.path.isdir(triple_path):
+            continue
 
-def merge_ctu_func_maps(ctu_dir, ctu_func_map_file, ctu_temp_fnmap_folder):
-    """ Merge individual function maps into a global one.
+        triple_arch = os.path.basename(triple_path)
+        fnmap_dir = os.path.join(ctu_dir, triple_arch,
+                                 ctu_temp_fnmap_folder)
 
-    As the collect phase runs parallel on multiple threads, all compilation
-    units are separately mapped into a temporary file in ctu_temp_fnmap_folder.
-    These function maps contain the mangled names of functions and the source
-    (AST generated from the source) which had them.
-    These files should be merged at the end into a global map file:
-    ctu_func_map_file."""
+        merged_fn_map = os.path.join(ctu_dir, triple_arch,
+                                     ctu_func_map_file)
+        merge(fnmap_dir, merged_fn_map)
 
-    triple_arches = glob.glob(os.path.join(ctu_dir, '*'))
-    for triple_path in triple_arches:
-        if os.path.isdir(triple_path):
-            triple_arch = os.path.basename(triple_path)
-            fnmap_dir = os.path.join(ctu_dir, triple_arch,
-                                     ctu_temp_fnmap_folder)
-
-            func_map_lines = generate_func_map_lines(fnmap_dir)
-            mangled_ast_pairs = create_global_ctu_function_map(func_map_lines)
-            write_global_map(ctu_dir, triple_arch, ctu_func_map_file,
-                             mangled_ast_pairs)
-
-            # Remove all temporary files
-            shutil.rmtree(fnmap_dir, ignore_errors=True)
+        # Remove all temporary files.
+        shutil.rmtree(fnmap_dir, ignore_errors=True)
 
 
 def generate_ast(triple_arch, action, source, config, env):
diff --git a/analyzer/codechecker_analyzer/pre_analysis_manager.py b/analyzer/codechecker_analyzer/pre_analysis_manager.py
index 5d07b46ad7..52881b6033 100644
--- a/analyzer/codechecker_analyzer/pre_analysis_manager.py
+++ b/analyzer/codechecker_analyzer/pre_analysis_manager.py
@@ -202,7 +202,7 @@ def signal_handler(signum, frame):
 
     # Postprocessing the pre analysis results.
     if ctu_data:
-        ctu_manager.merge_ctu_func_maps(
+        ctu_manager.merge_clang_extdef_mappings(
                 ctu_data.get('ctu_dir'),
                 ctu_data.get('ctu_func_map_file'),
                 ctu_data.get('ctu_temp_fnmap_folder'))
diff --git a/analyzer/tests/Makefile b/analyzer/tests/Makefile
index b099c90794..ff2667179e 100644
--- a/analyzer/tests/Makefile
+++ b/analyzer/tests/Makefile
@@ -20,8 +20,8 @@ pycodestyle:
 pycodestyle_in_env: venv_dev
 	$(ACTIVATE_DEV_VENV) && $(PYCODESTYLE_TEST_CMD)
 
-PYLINT_TEST_CMD = PYLINTRC=$(ROOT)/.pylintrc \
-	pylint ./bin/** ./codechecker_analyzer ./tests/**
+PYLINT_TEST_CMD = $(MAKE) -C $(CURRENT_DIR)/tools/merge_clang_extdef_mappings pylint && \
+	PYLINTRC=$(ROOT)/.pylintrc pylint ./bin/** ./codechecker_analyzer ./tests/**
 
 pylint:
 	$(PYLINT_TEST_CMD)
@@ -65,3 +65,10 @@ test_tu_collector:
 test_tu_collector_in_env:
 	$(ACTIVATE_DEV_VENV) && \
 	$(REPO_ROOT) make -C $(ROOT)/tools/tu_collector test
+
+test_merge_clang_extdef_mappings:
+	make -C tools/merge_clang_extdef_mappings test
+
+test_merge_clang_extdef_mappings_in_env:
+	$(ACTIVATE_DEV_VENV) && \
+	make -C tools/merge_clang_extdef_mappings test
diff --git a/analyzer/tools/merge_clang_extdef_mappings/.gitignore b/analyzer/tools/merge_clang_extdef_mappings/.gitignore
new file mode 100644
index 0000000000..e195e845f1
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/.gitignore
@@ -0,0 +1,3 @@
+build/
+dist/
+merge_clang_extdef_mappings.egg-info
diff --git a/analyzer/tools/merge_clang_extdef_mappings/.noserc b/analyzer/tools/merge_clang_extdef_mappings/.noserc
new file mode 100644
index 0000000000..512f4e1a08
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/.noserc
@@ -0,0 +1,13 @@
+[nosetests]
+
+# increase verbosity level
+verbosity=3
+
+# more detailed error messages on failed asserts
+detailed-errors=1
+
+# stop running tests on first error
+stop=1
+
+# do not capture stdout
+#nocapture=1
diff --git a/analyzer/tools/merge_clang_extdef_mappings/.pylintrc b/analyzer/tools/merge_clang_extdef_mappings/.pylintrc
new file mode 100644
index 0000000000..4822958e6c
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/.pylintrc
@@ -0,0 +1,377 @@
+[MASTER]
+
+# Specify a configuration file.
+#rcfile=
+
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+#init-hook=
+
+# Add files or directories to the blacklist. They should be base names, not
+# paths.
+ignore=CVS
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Use multiple processes to speed up Pylint.
+jobs=1
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code
+extension-pkg-whitelist=
+
+# Allow optimization of some AST trees. This will activate a peephole AST
+# optimizer, which will apply various small optimizations. For instance, it can
+# be used to obtain the result of joining multiple strings with the addition
+# operator. Joining a lot of strings can lead to a maximum recursion error in
+# Pylint and this flag can prevent that. It has one side effect, the resulting
+# AST will be different than the one from reality.
+optimize-ast=no
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE, UNDEFINED
+confidence=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once).You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use"--disable=all --enable=classes
+# --disable=W"
+disable=all
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time. See also the "--disable" option for examples.
+enable=logging-format-interpolation,old-style-class,unused-import,unused-variable,len-as-condition,bad-indentation,unpacking-in-except,import-star-module-level,parameter-unpacking,long-suffix,old-octal-literal,old-ne-operator,backtick,old-raise-syntax,print-statement,unpacking-in-except,import-star-module-level,parameter-unpacking,long-suffix,old-octal-literal,old-ne-operator,backtick,old-raise-syntax,print-statement,not-in-loop,function-redefined,continue-in-finally,abstract-class-instantiated,sstar-needs-assignment-target,duplicate-argument-name,too-many-star-expressions,nonlocal-and-global,return-outside-function,return-arg-in-generator,invalid-star-assignment-target,bad-reversed-sequence,nonexistent-operator,yield-outside-function,init-is-generator,nonlocal-without-binding,invalid-unary-operand-type,unsupported-binary-operation,no-member,not-callable,redundant-keyword-arg,assignment-from-no-return,assignment-from-none,not-context-manager,repeated-keyword,missing-kwoa,no-value-for-parameter,invalid-sequence-index,invalid-slice-index,too-many-function-args,unexpected-keyword-arg,unsupported-membership-test,unsubscriptable-object,unpacking-non-sequence,invalid-all-object,no-name-in-module,unbalanced-tuple-unpacking,undefined-variable,undefined-all-variable,used-before-assignment,format-needs-mapping,truncated-format-string,missing-format-string-key,mixed-format-string,too-few-format-args,bad-str-strip-call,too-many-format-args,bad-format-character,access-member-before-definition,method-hidden,assigning-non-slot,duplicate-bases,inconsistent-mro,inherit-non-class,invalid-slots,invalid-slots-object,no-method-argument,no-self-argument,unexpected-special-method-signature,non-iterator-returned,invalid-length-returned
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+output-format=text
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]".
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=yes
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details
+msg-template=[{msg_id}] {path}:{line:3d}:{column}: {msg}
+
+
+[SPELLING]
+
+# Spelling dictionary name. Available dictionaries: none. To make it working
+# install python-enchant package.
+spelling-dict=
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to indicated private dictionary in
+# --spelling-private-dict-file option instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[LOGGING]
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format
+logging-modules=logging
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=80
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=^\s*(# )?<?https?://\S+>?$
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=no
+
+# List of optional constructs for which whitespace checking is disabled. `dict-
+# separator` is used to allow tabulation in dicts, etc.: {1  : 1,\n222: 2}.
+# `trailing-comma` allows a space between comma and closing bracket: (a, ).
+# `empty-line` allows space-only lines.
+no-space-check=trailing-comma,dict-separator
+
+# Maximum number of lines in a module
+max-module-lines=2000
+
+# String used as indentation unit. This is usually "    " (4 spaces) or "\t" (1
+# tab).
+indent-string='    '
+
+# Number of spaces of indent required inside a hanging  or continued line.
+indent-after-paren=4
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+#notes=FIXME,XXX,TODO
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the name of dummy variables (i.e. expectedly
+# not used).
+dummy-variables-rgx=_$|dummy
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,_cb
+
+
+[BASIC]
+
+# List of builtins function names that should not be used, separated by a comma
+bad-functions=
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=i,j,k,ex,Run,_
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=foo,bar,baz,toto,tutu,tata
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Include a hint for the correct naming format with invalid-name
+include-naming-hint=no
+
+# Regular expression matching correct function names
+function-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for function names
+function-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct variable names
+variable-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for variable names
+variable-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct constant names
+const-rgx=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Naming hint for constant names
+const-name-hint=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Regular expression matching correct attribute names
+attr-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for attribute names
+attr-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct argument names
+argument-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for argument names
+argument-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct class attribute names
+class-attribute-rgx=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
+
+# Naming hint for class attribute names
+class-attribute-name-hint=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
+
+# Regular expression matching correct inline iteration names
+inlinevar-rgx=[A-Za-z_][A-Za-z0-9_]*$
+
+# Naming hint for inline iteration names
+inlinevar-name-hint=[A-Za-z_][A-Za-z0-9_]*$
+
+# Regular expression matching correct class names
+class-rgx=[A-Z_][a-zA-Z0-9]+$
+
+# Naming hint for class names
+class-name-hint=[A-Z_][a-zA-Z0-9]+$
+
+# Regular expression matching correct module names
+module-rgx=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Naming hint for module names
+module-name-hint=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Regular expression matching correct method names
+method-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for method names
+method-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=^_
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=50
+
+
+[ELIF]
+
+# Maximum number of nested blocks for function / method body
+max-nested-blocks=5
+
+
+[TYPECHECK]
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# List of classes names for which member attributes should not be checked
+# (useful for classes with attributes dynamically set). This supports can work
+# with qualified names.
+ignored-classes=
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[DESIGN]
+
+# Maximum number of arguments for function / method
+max-args=8
+
+# Argument names that match this expression will be ignored. Default to name
+# with leading underscore
+ignored-argument-names=_.*
+
+# Maximum number of locals for function / method body
+max-locals=20
+
+# Maximum number of return / yield for function / method body
+max-returns=6
+
+# Maximum number of branch for function / method body
+max-branches=12
+
+# Maximum number of statements in function / method body
+max-statements=50
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+# Maximum number of boolean expressions in a if statement
+max-bool-expr=5
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,TERMIOS,Bastion,rexec
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,__new__,setUp
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,_fields,_replace,_source,_make
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=Exception
diff --git a/analyzer/tools/merge_clang_extdef_mappings/.pypirc b/analyzer/tools/merge_clang_extdef_mappings/.pypirc
new file mode 100644
index 0000000000..52d57ec25f
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/.pypirc
@@ -0,0 +1,10 @@
+[distutils]
+index-servers =
+  pypi
+  testpypi
+
+[pypi]
+repository: https://upload.pypi.org/legacy/
+
+[testpypi]
+repository: https://test.pypi.org/legacy/
diff --git a/analyzer/tools/merge_clang_extdef_mappings/LICENSE.txt b/analyzer/tools/merge_clang_extdef_mappings/LICENSE.txt
new file mode 100644
index 0000000000..bd8b243dfa
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/LICENSE.txt
@@ -0,0 +1,218 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+       http://www.apache.org/licenses/LICENSE-2.0
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+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+--- LLVM Exceptions to the Apache 2.0 License ----
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diff --git a/analyzer/tools/merge_clang_extdef_mappings/MANIFEST.in b/analyzer/tools/merge_clang_extdef_mappings/MANIFEST.in
new file mode 100644
index 0000000000..c1ebcaeab4
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/MANIFEST.in
@@ -0,0 +1,2 @@
+include README.md
+include *.txt
diff --git a/analyzer/tools/merge_clang_extdef_mappings/Makefile b/analyzer/tools/merge_clang_extdef_mappings/Makefile
new file mode 100644
index 0000000000..b6633c2a8f
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/Makefile
@@ -0,0 +1,64 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+
+CURRENT_DIR = $(shell pwd)
+ROOT = $(CURRENT_DIR)
+
+BUILD_DIR = $(CURRENT_DIR)/build
+MERGE_CLANG_EXTDEF_MAPS_DIR = $(BUILD_DIR)/merge_clang_extdef_mappings
+
+ACTIVATE_DEV_VENV ?= . venv_dev/bin/activate
+ACTIVATE_RUNTIME_VENV ?= . venv/bin/activate
+
+VENV_DEV_REQ_FILE ?= requirements_py/dev/requirements.txt
+
+default: all
+
+all: package
+
+venv:
+	# Create a virtual environment which can be used to run the build package.
+	virtualenv -p python3 venv && $(ACTIVATE_RUNTIME_VENV)
+
+venv_dev:
+	# Create a virtual environment for development.
+	virtualenv -p python3 venv_dev && \
+		$(ACTIVATE_DEV_VENV) && pip install -r $(VENV_DEV_REQ_FILE)
+
+clean_venv_dev:
+	rm -rf venv_dev
+
+include tests/Makefile
+
+package:
+	# Install package in 'development mode'.
+	python setup.py develop
+
+build:
+	python setup.py build --build-purelib $(MERGE_CLANG_EXTDEF_MAPS_DIR)
+
+dist:
+	# Create a source distribution.
+	python setup.py sdist
+
+upload_test: dist
+	# Upload package to the TestPyPI repository.
+	$(eval PKG_NAME := $(shell python setup.py --name))
+	$(eval PKG_VERSION := $(shell python setup.py --version))
+	twine upload -r testpypi dist/$(PKG_NAME)-$(PKG_VERSION).tar.gz
+
+upload: dist
+	# Upload package to the PyPI repository.
+	$(eval PKG_NAME := $(shell python setup.py --name))
+	$(eval PKG_VERSION := $(shell python setup.py --version))
+	twine upload -r pypi dist/$(PKG_NAME)-$(PKG_VERSION).tar.gz
+
+clean:
+	rm -rf $(BUILD_DIR)
+	rm -rf dist
+	rm -rf merge_clang_extdef_mappings.egg-info
diff --git a/analyzer/tools/merge_clang_extdef_mappings/README.md b/analyzer/tools/merge_clang_extdef_mappings/README.md
new file mode 100644
index 0000000000..e3fe815fb0
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/README.md
@@ -0,0 +1,46 @@
+# merge-clang-extdef-mappings
+As the collect phase runs parallel on multiple threads, all compilation units
+are separately mapped into a temporary file in a temporary folder. These
+function maps contain the mangled names of functions and the source (AST
+generated from the source) which had them. These files should be merged at
+the end into a global map file.
+
+`merge-clang-extdef-mappings` is a python tool which can be used to merge
+individual function maps created by the
+[clang-extdef-mapping](https://github.com/llvm/llvm-project/blob/master/clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp)
+tool into a global one.
+
+
+## Install guide
+```sh
+# Create a Python virtualenv and set it as your environment.
+make venv
+source $PWD/venv/bin/activate
+
+# Build and install plist-to-html package.
+make package
+```
+
+## Usage
+```sh
+usage: merge-clang-extdef-mappings [-h] -i input -o output
+
+Merge individual clang extdef mapping files into one mapping file.
+
+optional arguments:
+  -h, --help            show this help message and exit
+  -i input, --input input
+                        Folder which contains multiple output of the 'clang-
+                        extdef-mapping' tool.
+  -o output, --output output
+                        Output file where the merged function maps will be
+                        stored into.
+
+Example:
+  merge-ctu-func-maps -i /path/to/fn_map_folder /path/to/externalDefMap.txt
+```
+
+## License
+
+The project is licensed under University of Illinois/NCSA Open Source License.
+See LICENSE.TXT for details.
\ No newline at end of file
diff --git a/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/__init__.py b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/__init__.py
new file mode 100644
index 0000000000..4259749345
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/__init__.py
@@ -0,0 +1,7 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
diff --git a/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/cli.py b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/cli.py
new file mode 100644
index 0000000000..cf3189d21a
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/cli.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+
+
+import argparse
+import logging
+import os
+import sys
+
+# If we run this script in an environment where
+# 'codechecker_merge_clang_extdef_mappings' module is not available we should
+# add the grandparent directory of this file to the system path.
+# TODO: This section will not be needed when CodeChecker will be delivered as
+# a python package and will be installed in a virtual environment with all the
+# dependencies.
+if __name__ == '__main__':
+    current_dir = os.path.dirname(os.path.realpath(__file__))
+    os.sys.path.append(os.path.dirname(current_dir))
+
+from codechecker_merge_clang_extdef_mappings import \
+    merge_clang_extdef_mappings  # noqa
+
+
+LOG = logging.getLogger('MergeClangExtdefMappings')
+
+msg_formatter = logging.Formatter('[%(levelname)s] - %(message)s')
+log_handler = logging.StreamHandler(sys.stdout)
+log_handler.setFormatter(msg_formatter)
+LOG.setLevel(logging.INFO)
+LOG.addHandler(log_handler)
+
+
+def __add_arguments_to_parser(parser):
+    """ Add arguments to the the given parser. """
+    parser.add_argument('-i', '--input',
+                        type=str,
+                        metavar='input',
+                        required=True,
+                        help="Folder which contains multiple output of the "
+                             "'clang-extdef-mapping' tool.")
+
+    parser.add_argument('-o', '--output',
+                        type=str,
+                        metavar='output',
+                        required=True,
+                        help="Output file where the merged function maps will "
+                             "be stored into.")
+
+
+def main():
+    """ Merge CTU funcs maps main command line. """
+    parser = argparse.ArgumentParser(
+        prog="merge-clang-extdef-mappings",
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description="Merge individual clang extdef mapping files into one "
+                    "mapping file.",
+        epilog="""Example:
+  merge-clang-extdef-mappings -i /path/to/fn_map_folder
+  /path/to/externalDefMap.txt""")
+
+    __add_arguments_to_parser(parser)
+
+    args = parser.parse_args()
+
+    merge_clang_extdef_mappings.merge(args.input, args.output)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/merge_clang_extdef_mappings.py b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/merge_clang_extdef_mappings.py
new file mode 100755
index 0000000000..482f050596
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/codechecker_merge_clang_extdef_mappings/merge_clang_extdef_mappings.py
@@ -0,0 +1,66 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+
+import glob
+import os
+
+
+def _generate_func_map_lines(func_map_dir):
+    """ Iterate over all lines of input files in random order. """
+    files = glob.glob(os.path.join(func_map_dir, '*'))
+    for func_map_file in files:
+        with open(func_map_file, 'r',
+                  encoding='utf-8', errors="ignore") as func_map:
+            for line in func_map:
+                yield line
+
+
+def _create_global_ctu_function_map(func_map_lines):
+    """ Takes iterator of individual function maps and creates a global map.
+
+    It will keeping only unique names. We leave conflicting names out of CTU.
+    A function map contains the id of a function (mangled name) and the
+    originating source (the corresponding AST file) name.
+    """
+    mangled_to_asts = {}
+
+    # We collect all occurences of a function name into a set.
+    for line in func_map_lines:
+        mangled_name, ast_file = line.strip().split(' ', 1)
+        if mangled_name not in mangled_to_asts:
+            mangled_to_asts[mangled_name] = {ast_file}
+        else:
+            mangled_to_asts[mangled_name].add(ast_file)
+
+    mangled_ast_pairs = []
+
+    for mangled_name, ast_files in mangled_to_asts.items():
+        if len(ast_files) == 1:
+            mangled_ast_pairs.append((mangled_name, ast_files.pop()))
+
+    return mangled_ast_pairs
+
+
+def merge(func_map_dir, output_file):
+    """ Merge individual function maps into a global one.
+
+    As the collect phase runs parallel on multiple threads, all compilation
+    units are separately mapped into a temporary file in ctu_temp_fnmap_folder.
+    These function maps contain the mangled names of functions and the source
+    (AST generated from the source) which had them.
+    These files should be merged at the end into a global map file:
+    ctu_func_map_file.
+    """
+    func_map_lines = _generate_func_map_lines(func_map_dir)
+    mangled_ast_pairs = _create_global_ctu_function_map(func_map_lines)
+
+    # Write (mangled function name, ast file) pairs into final file.
+    with open(output_file, 'w',
+              encoding='utf-8', errors='ignore') as out_file:
+        for mangled_name, ast_file in mangled_ast_pairs:
+            out_file.write('%s %s\n' % (mangled_name, ast_file))
diff --git a/analyzer/tools/merge_clang_extdef_mappings/requirements_py/dev/requirements.txt b/analyzer/tools/merge_clang_extdef_mappings/requirements_py/dev/requirements.txt
new file mode 100644
index 0000000000..bf35683890
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/requirements_py/dev/requirements.txt
@@ -0,0 +1,3 @@
+nose==1.3.7
+pycodestyle==2.4.0
+pylint==1.9.4
diff --git a/analyzer/tools/merge_clang_extdef_mappings/setup.py b/analyzer/tools/merge_clang_extdef_mappings/setup.py
new file mode 100644
index 0000000000..a61ab76b3e
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/setup.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import setuptools
+
+with open("README.md", "r") as fh:
+    long_description = fh.read()
+
+setuptools.setup(
+    name="merge-clang-extdef-mappings",
+    version="0.1.0",
+    author='CodeChecker Team (Ericsson)',
+    description="Merge individual function maps into a global one.",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+    url="https://github.com/Ericsson/CodeChecker",
+    keywords=['clang', 'ctu', 'merge', 'func-map', 'static-analysis',
+              'analysis'],
+    license='LICENSE.txt',
+    packages=setuptools.find_packages(),
+    include_package_data=True,
+    classifiers=[
+        "Environment :: Console",
+        "Intended Audience :: Developers",
+        "Operating System :: POSIX",
+        "Programming Language :: Python :: 3"
+    ],
+    entry_points={
+        'console_scripts': [
+            'merge-clang-extdef-mappings = codechecker_merge_clang_extdef_mappings.cli:main'
+        ]
+    },
+)
diff --git a/analyzer/tools/merge_clang_extdef_mappings/tests/Makefile b/analyzer/tools/merge_clang_extdef_mappings/tests/Makefile
new file mode 100644
index 0000000000..02e9452bde
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/tests/Makefile
@@ -0,0 +1,36 @@
+# Environment variables to run tests.
+
+REPO_ROOT ?= REPO_ROOT=$(ROOT)
+
+# Nose test runner configuration options.
+NOSECFG = --config .noserc
+
+test: pycodestyle pylint test_unit
+
+test_in_env: pycodestyle_in_env pylint_in_env test_unit_in_env
+
+PYCODESTYLE_TEST_CMD = pycodestyle codechecker_merge_clang_extdef_mappings tests
+
+pycodestyle:
+	$(PYCODESTYLE_TEST_CMD)
+
+pycodestyle_in_env: venv_dev
+	$(ACTIVATE_DEV_VENV) && $(PYCODESTYLE_TEST_CMD)
+
+PYLINT_TEST_CMD = PYLINTRC=$(ROOT)/.pylintrc \
+	pylint ./codechecker_merge_clang_extdef_mappings ./tests/**
+
+pylint:
+	$(PYLINT_TEST_CMD)
+
+pylint_in_env: venv
+	$(ACTIVATE_DEV_VENV) && $(PYLINT_TEST_CMD)
+
+UNIT_TEST_CMD = $(REPO_ROOT) \
+  nosetests $(NOSECFG) tests/unit
+
+test_unit:
+	$(UNIT_TEST_CMD)
+
+test_unit_in_env: venv_dev
+	$(ACTIVATE_DEV_VENV) && $(UNIT_TEST_CMD)
diff --git a/analyzer/tools/merge_clang_extdef_mappings/tests/unit/__init__.py b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/__init__.py
new file mode 100644
index 0000000000..4259749345
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/__init__.py
@@ -0,0 +1,7 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
diff --git a/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/__init__.py b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/__init__.py
new file mode 100644
index 0000000000..b3a2aa1f9d
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/__init__.py
@@ -0,0 +1,54 @@
+# coding=utf-8
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+""" Setup for the test package analyze. """
+
+import os
+import shutil
+import tempfile
+
+
+def get_workspace(test_id='test'):
+    """ Return a temporary workspace for the tests. """
+    workspace_root = os.environ.get("MERGE_CTU_FUNC_MAPS_TEST_WORKSPACE_ROOT")
+    if not workspace_root:
+        # if no external workspace is set create under the build dir
+        workspace_root = os.path.join(os.environ['REPO_ROOT'], 'build',
+                                      'workspace')
+
+    if not os.path.exists(workspace_root):
+        os.makedirs(workspace_root)
+
+    if test_id:
+        return tempfile.mkdtemp(prefix=test_id + "-", dir=workspace_root)
+    else:
+        return workspace_root
+
+
+# Test workspace should be initialized in this module.
+TEST_WORKSPACE = None
+
+
+def setup_package():
+    """ Setup the environment for the tests. """
+
+    global TEST_WORKSPACE
+    TEST_WORKSPACE = get_workspace('merge_clang_extdef_mappings')
+
+    os.environ['TEST_WORKSPACE'] = TEST_WORKSPACE
+
+
+def teardown_package():
+    """ Delete the workspace associated with this test. """
+
+    # TODO: If environment variable is set keep the workspace
+    # and print out the path.
+    global TEST_WORKSPACE
+
+    print("Removing: " + TEST_WORKSPACE)
+    shutil.rmtree(TEST_WORKSPACE)
diff --git a/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/merge_clang_extdef_mappings.py b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/merge_clang_extdef_mappings.py
new file mode 100644
index 0000000000..dd0fc9ddd2
--- /dev/null
+++ b/analyzer/tools/merge_clang_extdef_mappings/tests/unit/merge_clang_extdef_mappings/merge_clang_extdef_mappings.py
@@ -0,0 +1,62 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+
+import os
+import unittest
+
+from codechecker_merge_clang_extdef_mappings import merge_clang_extdef_mappings
+
+
+class MergeClangExtdefMappingsTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(self):
+        """ Initialize test files. """
+        self.test_workspace = os.environ['TEST_WORKSPACE']
+
+        self.extdef_maps_dir = os.path.join(self.test_workspace,
+                                            "extdef_maps")
+
+        if not os.path.exists(self.extdef_maps_dir):
+            os.makedirs(self.extdef_maps_dir)
+
+        self.extdef_map_1_lines = ["c:@F@f# path/to/file.cpp.ast",
+                                   "c:@F@g# path/to/file.cpp.ast",
+                                   "c:@F@both# path/to/file.cpp.ast"]
+
+        extdef_map_file_1 = os.path.join(self.extdef_maps_dir,
+                                         'externalDefMap1.txt')
+        with open(extdef_map_file_1, 'w',
+                  encoding='utf-8', errors='ignore') as map_f:
+            map_f.write('\n'.join(self.extdef_map_1_lines))
+
+        self.extdef_map_2_lines = ["c:@F@main# path/to/file2.cpp.ast",
+                                   "c:@F@h# path/to/file2.cpp.ast",
+                                   "c:@F@both# path/to/file2.cpp.ast"]
+
+        extdef_map_file_2 = os.path.join(self.extdef_maps_dir,
+                                         'externalDefMap2.txt')
+        with open(extdef_map_file_2, 'w',
+                  encoding='utf-8', errors='ignore') as map_f:
+            map_f.write('\n'.join(self.extdef_map_2_lines))
+
+    def test_merge_clang_extdef_mappings(self):
+        """ Test merging multiple func map files. """
+
+        output_file = os.path.join(self.test_workspace, 'externalDefMap.txt')
+        merge_clang_extdef_mappings.merge(self.extdef_maps_dir, output_file)
+
+        with open(output_file, 'r',
+                  encoding='utf-8', errors='ignore') as o_file:
+            lines = o_file.read().split('\n')
+
+        expected_lines = ["c:@F@f# path/to/file.cpp.ast",
+                          "c:@F@g# path/to/file.cpp.ast",
+                          "c:@F@main# path/to/file2.cpp.ast",
+                          "c:@F@h# path/to/file2.cpp.ast"]
+        for expected_line in expected_lines:
+            self.assertTrue(expected_line in lines)