This report presents the forensic synthetic code analysis of google/tcmalloc, a C++ project with 5,282 GitHub stars. SynthScan v2.0 examined 41,174 lines of code across 148 source files, recording 330 pattern matches distributed across 2 syntactic categories. The overall adjusted score of 8.0 places this repository in the Low AI signal band.
The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).
Longitudinal tracking requires multiple scan runs. Once this repository is re-scanned after new commits land, this chart will visualise how the synthetic code signal evolves over time — enabling you to detect whether AI authorship is growing, stabilising, or being actively corrected by human engineers.
Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.
This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.
The scanner identified 330 distinct pattern matches across 2 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.
Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | CMakeLists.txt | 1 | # Copyright 2026 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/page_allocator_test_util.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/tcmalloc.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/tcmalloc.h | 21 | COMMENT | |
| LOW | tcmalloc/transfer_cache.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/transfer_cache.h | 21 | #include <algorithm> | COMMENT |
| LOW | tcmalloc/huge_address_map.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/huge_address_map.h | 21 | #include "tcmalloc/huge_pages.h" | COMMENT |
| LOW | tcmalloc/new_extension.h | 1 | // Copyright 2020 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/experiment.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/experiment.h | 21 | COMMENT | |
| LOW | tcmalloc/profile_marshaler.h | 1 | // Copyright 2021 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/malloc_hook.h | 1 | // Copyright 2025 The TCMalloc Authors. | COMMENT |
| LOW | tcmalloc/malloc_hook.h | 81 | // | COMMENT |
| LOW | tcmalloc/global_stats.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/static_vars.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/static_vars.h | 21 | #include <stdint.h> | COMMENT |
| LOW | tcmalloc/static_vars.h | 41 | #include "tcmalloc/internal/numa.h" | COMMENT |
| LOW | tcmalloc/huge_cache.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/huge_cache.h | 21 | COMMENT | |
| LOW | tcmalloc/huge_cache.h | 121 | .freq = absl::base_internal::CycleClock::Frequency}) {} | COMMENT |
| LOW | tcmalloc/pages.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/pages.h | 21 | #include <limits> | COMMENT |
| LOW | tcmalloc/CMakeLists.txt | 1 | # Copyright 2026 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 21 | #include <algorithm> | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 41 | #include "tcmalloc/common.h" | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 261 | hugepage_residency_state_ = state; | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 361 | // Bitmap of pages based on them being released to the OS. | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1141 | COMMENT | |
| LOW | tcmalloc/huge_page_filler.h | 1221 | Length FreePagesInPartialAllocs() const; | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1281 | ABSL_EXCLUSIVE_LOCKS_REQUIRED(pageheap_lock); | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1341 | size_t ListFor(Length longest, size_t chunk, AccessDensityPrediction density, | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1641 | // If all native pages corresponding to this TCMalloc page are unbacked, | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1781 | n == Length(1)); | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1801 | // | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 1821 | // that are freshly donated as less preferable than hugepages that have been | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 2061 | explicit SampledTrackerTreatment(Clock clock, MemoryTag tag, | COMMENT |
| LOW | tcmalloc/huge_page_filler.h | 2601 | // 1. Collect up to kTotalTrackersToScan trackers using | COMMENT |
| LOW | tcmalloc/pagemap.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/pagemap.h | 21 | // | COMMENT |
| LOW | tcmalloc/page_allocator.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/page_allocator.h | 21 | #include <cstdint> | COMMENT |
| LOW | tcmalloc/sizemap.h | 1 | // Copyright 2022 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/sizemap.h | 21 | #include <limits> | COMMENT |
| LOW | tcmalloc/sizemap.h | 61 | private: | COMMENT |
| LOW | tcmalloc/sizemap.h | 81 | // 1025 (1025 + 127 + (120<<7)) / 128 129 | COMMENT |
| LOW | tcmalloc/sizemap.h | 101 | // partition 1 will contain the same information as for partition 0. | COMMENT |
| LOW | tcmalloc/sizemap.h | 121 | // | COMMENT |
| LOW | tcmalloc/sizemap.h | 181 | // rely on Init() to populate things. | COMMENT |
| LOW | tcmalloc/central_freelist.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/central_freelist.h | 21 | #include <array> | COMMENT |
| LOW | tcmalloc/central_freelist.h | 41 | #include "tcmalloc/internal/central_freelist_hooks.h" | COMMENT |
| LOW | tcmalloc/central_freelist.h | 281 | // list index. | COMMENT |
| LOW | tcmalloc/central_freelist.h | 381 | StatsCounter num_same_spans_[kMaxObjectsToMove]; | COMMENT |
| LOW | tcmalloc/central_freelist.h | 401 | // using NumSpansWith(bitwidth) to obtain the number of spans associated | COMMENT |
| LOW | tcmalloc/central_freelist.h | 541 | // Depending on the number of kNumLists and the number of objects per span, we | COMMENT |
| LOW | tcmalloc/sampler.h | 1 | // Copyright 2019 The TCMalloc Authors | COMMENT |
| LOW | tcmalloc/sampler.h | 21 | COMMENT | |
| LOW | tcmalloc/sampler.h | 41 | // the probability of sampling a 4K allocation is about 0.00778 | COMMENT |
| 269 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | tcmalloc/internal/prefetch.h | 49 | // Example usage: | COMMENT |