Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues
Project coverage
Per-fuzzer coverage

Table of contents

Project overview: croaring
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: croaring_fuzzer
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Fuzzer: croaring_fuzzer_cc
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/croaring_fuzzer.c
Dictionary
Fuzzer function priority
/src/croaring_fuzzer_cc.cc
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2026-10-17

Project overview: croaring

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
63.0%
655 / 1035
Cyclomatic complexity statically reachable by fuzzers
61.0%
3629 / 5982
Runtime code coverage of functions
54.0%
559 / 1035

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
croaring_fuzzer /src/croaring_fuzzer.c 213 765 13 22 1773 939 croaring_fuzzer.c
croaring_fuzzer_cc /src/croaring_fuzzer_cc.cc 621 254 12 29 6457 3200 croaring_fuzzer_cc.cc

Project functions overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

For further technical details on the meaning of columns in the below table, please see the Glossary .

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzzer details

Fuzzer: croaring_fuzzer

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 77 18.1%
gold [1:9] 6 1.41%
yellow [10:29] 1 0.23%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 340 80.1%
All colors 424 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
16 67 roaring_bitmap_set_copy_on_write call site: 00067 roaring_unshare_all
6 155 array_container_try_add call site: 00155 bitset_container_from_array
6 215 art_node_child_at call site: 00215 art_node_prev_child
5 114 avx2_harley_seal_popcount256 call site: 00114 _scalar_bitset_container_compute_cardinality
5 410 containerptr_roaring64_bitmap_add call site: 00410 container_free
4 58 run_container_free call site: 00058 shared_container_free
3 90 bitset_container_compute_cardinality call site: 00090 avx512_vpopcount
3 135 roaring_bitmap_contains call site: 00135 array_container_contains
2 43 array_container_grow call site: 00043 roaring_free
2 166 makeRoomAtIndex call site: 00166 container_free
2 177 bitmap32 call site: 00177 printf
2 190 roaring64_bitmap_free call site: 00190 art_free

Runtime coverage analysis

Covered functions
184
Functions that are reachable but not covered
34
Reachable functions
213
Percentage of reachable functions covered
84.04%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/src/croaring_fuzzer.c 3
/src/croaring/src/roaring.c 7
/src/croaring/src/memory.c 5
/src/croaring/src/roaring_array.c 9
/src/croaring/src/containers/bitset.c 10
/src/croaring/src/isadetection.c 5
/src/croaring/src/containers/run.c 11
/src/croaring/include/roaring/containers/run.h 6
/src/croaring/src/containers/array.c 9
/src/croaring/include/roaring/containers/array.h 6
/src/croaring/src/containers/containers.c 5
/src/croaring/include/roaring/portability.h 5
/src/croaring/include/roaring/roaring.h 3
/src/croaring/include/roaring/containers/containers.h 5
/src/croaring/include/roaring/bitset_util.h 6
/src/croaring/include/roaring/roaring_array.h 6
/src/croaring/include/roaring/array_util.h 1
/src/croaring/include/roaring/containers/bitset.h 3
/src/croaring/src/containers/convert.c 1
/src/croaring/src/roaring64.c 25
/src/croaring/src/art/art.c 78
/usr/include/x86_64-linux-gnu/bits/byteswap.h 1

Fuzzer: croaring_fuzzer_cc

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 463 27.7%
gold [1:9] 13 0.77%
yellow [10:29] 22 1.31%
greenyellow [30:49] 20 1.19%
lawngreen 50+ 1150 68.9%
All colors 1668 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
23 548 container_and call site: 00548 bitset_bitset_container_intersection
18 856 union_vector16 call site: 00856 avx512_union_uint16
15 705 container_andnot call site: 00705 bitset_bitset_container_andnot
15 976 container_xor call site: 00976 bitset_bitset_container_xor
13 633 avx2_harley_seal_popcount256 call site: 00633 array_container_from_bitset
12 447 container_and_cardinality call site: 00447 bitset_container_and_justcard
12 821 container_or call site: 00821 bitset_container_or
11 146 convert_run_optimize call site: 00146 run_container_create_given_capacity
10 1210 roaring_inplace_merge_bulk call site: 01210 container_ior
10 1291 container_iandnot call site: 01291 run_bitset_container_iandnot
10 1349 bitset_container_equals call site: 01349 run_container_equals_bitset
9 1415 container_is_subset call site: 01415 run_container_is_subset_bitset

Runtime coverage analysis

Covered functions
460
Functions that are reachable but not covered
110
Reachable functions
621
Percentage of reachable functions covered
82.29%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/src/croaring_fuzzer_cc.cc 2
/src/croaring/cpp/roaring/roaring.hh 61
/src/croaring/include/roaring/roaring.h 7
/src/croaring/src/roaring.c 65
/src/croaring/src/roaring_array.c 25
/src/croaring/src/memory.c 5
/src/croaring/include/roaring/roaring_array.h 8
/src/croaring/include/roaring/array_util.h 4
/src/croaring/include/roaring/portability.h 6
/src/croaring/include/roaring/containers/containers.h 39
/src/croaring/src/containers/containers.c 7
/src/croaring/src/containers/bitset.c 46
/src/croaring/src/isadetection.c 5
/src/croaring/src/containers/array.c 26
/src/croaring/src/containers/run.c 28
/src/croaring/include/roaring/containers/bitset.h 9
/src/croaring/include/roaring/containers/array.h 18
/src/croaring/src/containers/convert.c 10
/src/croaring/include/roaring/containers/run.h 26
/src/croaring/include/roaring/bitset_util.h 20
/src/croaring/src/bitset_util.c 22
/src/croaring/src/array_util.c 35
/src/croaring/src/containers/mixed_intersection.c 12
/src/croaring/src/containers/mixed_andnot.c 19
/src/croaring/src/containers/mixed_union.c 6
/src/croaring/src/containers/mixed_xor.c 16
/src/croaring/src/containers/mixed_equal.c 3
/src/croaring/src/containers/mixed_subset.c 5
/src/croaring/src/containers/mixed_negation.c 9

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
roaring64_bitmap_add_offset_signed /src/croaring/src/roaring64.c 3 ['N/A', 'bool', 'size_t'] 10 0 316 57 21 194 0 881 130
roaring64_bitmap_shrink_to_fit /src/croaring/src/roaring64.c 1 ['N/A'] 6 0 85 14 6 54 0 279 130
roaring64_bitmap_remove_range /src/croaring/src/roaring64.c 3 ['N/A', 'size_t', 'size_t'] 14 0 24 6 3 139 0 594 123
roaring_bitmap_or_many /src/croaring/src/roaring.c 2 ['size_t', 'N/A'] 12 0 58 14 6 138 0 623 89
roaring64_bitmap_portable_deserialize_frozen /src/croaring/src/roaring64.c 2 ['N/A', 'size_t'] 10 0 207 47 21 99 0 408 88
roaring_bitmap_xor_many /src/croaring/src/roaring.c 2 ['size_t', 'N/A'] 12 0 58 14 6 141 0 623 83
roaring64_bitmap_to_uint64_array /src/croaring/src/roaring64.c 2 ['N/A', 'N/A'] 7 0 16 3 2 47 0 191 59
roaring_bitmap_flip /src/croaring/src/roaring.c 3 ['N/A', 'size_t', 'size_t'] 12 0 36 9 4 105 0 483 55
roaring_bitmap_range_uint32_array /src/croaring/src/roaring.c 4 ['N/A', 'size_t', 'size_t', 'N/A'] 4 0 19 3 2 12 0 82 53
roaring_bitmap_rank_many /src/croaring/src/roaring.c 4 ['N/A', 'N/A', 'N/A', 'N/A'] 6 0 167 28 11 17 0 124 41

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
74.0%
762 / 1035
Cyclomatic complexity statically reachable by fuzzers
75.0%
4480 / 5982

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzz engine guidance

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

/src/croaring_fuzzer.c

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name 

-focus_function=['roaring_bitmap_set_copy_on_write', 'array_container_try_add', 'art_node_child_at', 'avx2_harley_seal_popcount256', 'containerptr_roaring64_bitmap_add', 'run_container_free', 'bitset_container_compute_cardinality', 'roaring_bitmap_contains', 'array_container_grow', 'makeRoomAtIndex']

/src/croaring_fuzzer_cc.cc

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name 

-focus_function=['container_and', 'union_vector16', 'container_andnot', 'container_xor', 'avx2_harley_seal_popcount256', 'container_and_cardinality', 'container_or', 'convert_run_optimize', 'roaring_inplace_merge_bulk', 'container_iandnot']

Runtime coverage analysis

This section shows analysis of runtime coverage data.

For futher technical details on how this section is generated, please see the Glossary .

Complex functions with low coverage

Func name Function total lines Lines covered at runtime percentage covered Reached by fuzzers
array_container_validate 35 17 48.57% ['croaring_fuzzer']
container_internal_validate 36 14 38.88% ['croaring_fuzzer']
roaring_bitmap_internal_validate 62 34 54.83% ['croaring_fuzzer']
container_iterator_next 56 29 51.78% ['croaring_fuzzer_cc']
container_ior 82 44 53.65% ['croaring_fuzzer_cc']
container_iandnot 56 29 51.78% ['croaring_fuzzer_cc']
array_container_to_uint32_array 48 10 20.83% ['croaring_fuzzer_cc']
container_iterator_lower_bound 33 15 45.45% ['croaring_fuzzer_cc']
convert_run_optimize 88 33 37.5% ['croaring_fuzzer_cc']
run_bitset_container_andnot 37 18 48.64% ['croaring_fuzzer_cc']
run_bitset_container_intersection 77 20 25.97% ['croaring_fuzzer_cc']

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
[] []
/src/croaring/src/containers/bitset.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_intersection.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/containers/containers.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/include/roaring/portability.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_union.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/cpp/roaring/roaring.hh ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/include/roaring/bitset/bitset.h [] []
/src/croaring/include/roaring/bitset_util.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/include/roaring/roaring_array.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/roaring.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/bitset_util.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/containers/array.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/memory.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_subset.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_andnot.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/art/art.c ['croaring_fuzzer'] ['croaring_fuzzer']
/src/croaring/src/containers/mixed_negation.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/include/roaring/containers/bitset.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/include/roaring/roaring.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_equal.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/roaring_array.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/roaring64.c ['croaring_fuzzer'] ['croaring_fuzzer']
/src/croaring/src/containers/convert.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/include/roaring/containers/run.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/isadetection.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/bitset.c [] []
/usr/include/x86_64-linux-gnu/bits/byteswap.h ['croaring_fuzzer'] []
/src/croaring/include/roaring/containers/containers.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring_fuzzer_cc.cc ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/array_util.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/src/containers/mixed_xor.c ['croaring_fuzzer_cc'] ['croaring_fuzzer_cc']
/src/croaring/include/roaring/containers/array.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/include/roaring/array_util.h ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/src/croaring/src/containers/run.c ['croaring_fuzzer', 'croaring_fuzzer_cc'] ['croaring_fuzzer', 'croaring_fuzzer_cc']
/usr/local/bin/../include/c++/v1/stdexcept [] []
/src/croaring/include/roaring/roaring64.h [] []
/src/croaring_fuzzer.c ['croaring_fuzzer'] ['croaring_fuzzer']

Directories in report

Directory
/src/croaring/cpp/roaring/
/src/croaring/include/roaring/
/usr/local/bin/../include/c++/v1/
/src/croaring/src/art/
/src/
/src/croaring/src/containers/
/src/croaring/include/roaring/bitset/
/src/croaring/include/roaring/containers/
/src/croaring/src/
/usr/include/x86_64-linux-gnu/bits/

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
croaring_fuzzer fuzzerLogFile-0-EkDx0NyIzL.data fuzzerLogFile-0-EkDx0NyIzL.data.yaml croaring_fuzzer.covreport
croaring_fuzzer_cc fuzzerLogFile-0-aFG3vBWYIf.data fuzzerLogFile-0-aFG3vBWYIf.data.yaml croaring_fuzzer_cc.covreport