• There are 200 files with units, with 117,797 lines of code.
• 12 very complex files (McCabe index sum 251+; 19,648 lines of code)
• 21 complex files (McCabe index sum 126-250; 22,321 lines of code)
• 52 medium complex files (McCabe index sum 51-125; 35,478 lines of code)
• 31 slightly complex files (McCabe index sum 26-50; 16,076 lines of code)
• 84 simple files (McCabe index sum 1-25; 24,274 lines of code)
• 164 main files have no units (e.g. languages without unit analysis, or files without functions) and are not classified.

The McCabe index of a file grows with its size: per 100 lines tells a large but plain file from a dense one, and most complex unit whether the complexity sits in one unit or is spread over many.

File	# lines	# units	McCabe index (sum)	per 100 lines	most complex unit
parser.rs in src/backend/arm/assembler	2104	48	560	27	51
peephole.rs in src/backend/i686/codegen	1541	58	462	30	65
arm_neon.h in include	2409	279	450	19	6
long_double.rs in src/common	2467	148	442	18	55
parser.rs in src/backend/x86/assembler	1738	51	418	24	85
simplify.rs in src/passes	2325	131	332	14	62
scan.rs in src/frontend/lexer	992	28	331	33	30
macro_defs.rs in src/frontend/preprocessor	1165	25	302	26	59
elf_writer_common.rs in src/backend	1420	38	295	21	39
global_init.rs in src/ir/lowering	1592	49	270	17	23
peephole.rs in src/backend/riscv/codegen	946	48	263	28	92
peephole.rs in src/backend/arm/codegen	949	47	255	27	72
emmintrin.h in include	1250	172	245	20	5
generation.rs in src/backend	1045	23	243	23	33
analysis.rs in src/frontend/sema	1547	42	235	15	40
xmmintrin.h in include	991	127	214	22	9
cfg_simplify.rs in src/passes	1126	42	210	19	18
avx2intrin.h in include	966	80	202	21	13
inline.rs in src/passes	1264	21	196	16	43
elf_writer.rs in src/backend/riscv/assembler	1170	20	190	16	30
conditionals.rs in src/frontend/preprocessor	686	20	184	27	51
asm_preprocess.rs in src/backend	1134	46	182	16	32
liveness.rs in src/backend	912	26	178	20	30
expr_types.rs in src/ir/lowering	1197	19	174	15	30
stmt_init.rs in src/ir/lowering	901	18	174	19	46
global_init_compound_ptrs.rs in src/ir/lowering	805	13	151	19	22
common.rs in src/backend	1352	31	150	11	25
parser.rs in src/backend/riscv/assembler	774	20	145	19	31
licm.rs in src/passes	1053	19	144	14	55
mmintrin.h in include	730	59	133	18	7
traits.rs in src/backend	1038	68	130	13	25
constant_fold.rs in src/passes	829	49	129	16	24
div_by_const.rs in src/passes	1551	35	127	8	8
narrow.rs in src/passes	753	19	121	16	26
inline_asm.rs in src/backend	786	12	120	15	22
promote.rs in src/ir/mem2reg	974	19	118	12	36
stmt.rs in src/ir/lowering	1100	13	116	11	23
const_eval.rs in src/frontend/sema	982	25	115	12	24
asm_emitter.rs in src/backend/i686/codegen	594	17	114	19	21
func_lowering.rs in src/ir/lowering	551	17	112	20	24
pipeline.rs in src/driver	736	11	110	15	38
pipeline.rs in src/frontend/preprocessor	614	12	106	17	58
emit.rs in src/backend/i686/codegen	1847	44	105	6	12
if_convert.rs in src/passes	599	11	104	17	27
asm_emitter.rs in src/backend/x86/codegen	514	10	103	20	23
struct_init.rs in src/ir/lowering	771	16	102	13	17
dead_statics.rs in src/passes	344	10	101	29	44
asm_emitter.rs in src/backend/arm/codegen	386	16	97	25	12
asm_expr.rs in src/backend	341	18	95	28	43
types.rs in src/common	1391	15	93	7	18

• File complexity is the sum of the McCabe indexes (conditional complexity) of the units (methods, functions...) in a file.
• Files are classified in five categories based on that sum: 1-25 (simple files), 26-50 (slightly complex files), 51-125 (medium complex files), 126-250 (complex files), 251+ (very complex files). The default bands are five times the unit complexity bands, as a file is a group of units.
• Only main code files with units are classified. Files without units (languages without unit analysis, or files without functions) have no complexity to measure and are left out rather than counted as simple.
• A very complex file holds many decisions, which often means it has too many responsibilities: a candidate to split, and a place where changes need more testing.