Implement a memory allocator in C11 — claude-code vs opencode vs pi vs antigravity

claude-codeclaude-opus-4-8view session

Implement a memory allocator in C11 in this directory. Files: alloc.c, alloc.h (my_malloc, my_free, my_calloc, my_realloc managing a 1 MiB static byte arena — first-fit free list with block splitting and coalescing of adjacent free blocks on free, 16-byte alignment, per-block canaries with a my_heap_check() validator that walks the heap, and my_stats() reporting bytes in use, free block count, and largest free block), tests.c (a deterministic seeded stress test: 100k mixed malloc/free/realloc ops mirrored against a shadow table, filling each allocation with a pattern and verifying it before free; fragmentation scenario tests proving coalescing recovers the largest block; a canary-violation detection test), Makefile (clang -std=c11 -Wall -Wextra -fsanitize=address,undefined). Build with make, run the tests, and fix failures until everything passes clean.

Makefile

1CC      := clang
2CFLAGS  := -std=c11 -Wall -Wextra -fsanitize=address,undefined -g -O1
3LDFLAGS := -fsanitize=address,undefined
4
5OBJ := alloc.o tests.o
6
7.PHONY: all run clean
8
9all: tests
10
11tests: $(OBJ)
12	$(CC) $(LDFLAGS) -o $@ $(OBJ)
13
14alloc.o: alloc.c alloc.h
15	$(CC) $(CFLAGS) -c alloc.c -o $@
16
17tests.o: tests.c alloc.h
18	$(CC) $(CFLAGS) -c tests.c -o $@
19
20run: tests
21	ASAN_OPTIONS=detect_leaks=1 UBSAN_OPTIONS=halt_on_error=1 ./tests
22
23clean:
24	rm -f tests $(OBJ)
25

steps: 51
duration: 12m 49s
errors: 10
files: 4

session 6da6e019-501read this session →

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opencodegpt-5.5view session

"Implement a memory allocator in C11 in this directory. Files: alloc.c, alloc.h (my_malloc, my_free, my_calloc, my_realloc managing a 1 MiB static byte arena — first-fit free list with block splitting and coalescing of adjacent free blocks on free, 16-byte alignment, per-block canaries with a my_heap_check() validator that walks the heap, and my_stats() reporting bytes in use, free block count, and largest free block), tests.c (a deterministic seeded stress test: 100k mixed malloc/free/realloc ops mirrored against a shadow table, filling each allocation with a pattern and verifying it before free; fragmentation scenario tests proving coalescing recovers the largest block; a canary-violation detection test), Makefile (clang -std=c11 -Wall -Wextra -fsanitize=address,undefined). Build with make, run the tests, and fix failures until everything passes clean."

Makefile

1CC := clang
2CFLAGS := -std=c11 -Wall -Wextra -fsanitize=address,undefined -g
3LDFLAGS := -fsanitize=address,undefined
4
5.PHONY: all test clean
6
7all: tests
8
9tests: alloc.o tests.o
10	$(CC) $(LDFLAGS) -o $@ alloc.o tests.o
11
12alloc.o: alloc.c alloc.h
13	$(CC) $(CFLAGS) -c alloc.c
14
15tests.o: tests.c alloc.h
16	$(CC) $(CFLAGS) -c tests.c
17
18test: tests
19	./tests
20
21clean:
22	rm -f tests *.o
23

steps: 45
duration: 2m 20s
errors: 0
files: 4

session a5c0bade-919read this session →

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pigpt-5.5 · mediumview session

Implement a memory allocator in C11 in this directory. Files: alloc.c, alloc.h (my_malloc, my_free, my_calloc, my_realloc managing a 1 MiB static byte arena — first-fit free list with block splitting and coalescing of adjacent free blocks on free, 16-byte alignment, per-block canaries with a my_heap_check() validator that walks the heap, and my_stats() reporting bytes in use, free block count, and largest free block), tests.c (a deterministic seeded stress test: 100k mixed malloc/free/realloc ops mirrored against a shadow table, filling each allocation with a pattern and verifying it before free; fragmentation scenario tests proving coalescing recovers the largest block; a canary-violation detection test), Makefile (clang -std=c11 -Wall -Wextra -fsanitize=address,undefined). Build with make, run the tests, and fix failures until everything passes clean.

Makefile

1CC := clang
2CFLAGS := -std=c11 -Wall -Wextra -fsanitize=address,undefined -g -O1
3LDFLAGS := -fsanitize=address,undefined
4
5.PHONY: all test clean
6
7all: tests
8
9tests: tests.o alloc.o
10	$(CC) $(LDFLAGS) -o $@ $^
11
12%.o: %.c alloc.h
13	$(CC) $(CFLAGS) -c $< -o $@
14
15test: tests
16	./tests
17
18clean:
19	rm -f tests *.o
20

steps: 44
duration: 2m 36s
errors: 4
files: 4

session 8a65b7eb-a82read this session →

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antigravitygeminiview session

Implement a memory allocator in C11 in this directory. Files: alloc.c, alloc.h (my_malloc, my_free, my_calloc, my_realloc managing a 1 MiB static byte arena — first-fit free list with block splitting and coalescing of adjacent free blocks on free, 16-byte alignment, per-block canaries with a my_heap_check() validator that walks the heap, and my_stats() reporting bytes in use, free block count, and largest free block), tests.c (a deterministic seeded stress test: 100k mixed malloc/free/realloc ops mirrored against a shadow table, filling each allocation with a pattern and verifying it before free; fragmentation scenario tests proving coalescing recovers the largest block; a canary-violation detection test), Makefile (clang -std=c11 -Wall -Wextra -fsanitize=address,undefined). Build with make, run the tests, and fix failures until everything passes clean.

Makefile

1CC = clang
2CFLAGS = -std=c11 -Wall -Wextra -fsanitize=address,undefined -g
3
4SRCS = alloc.c tests.c
5OBJS = $(SRCS:.c=.o)
6TARGET = test_runner
7
8all: test
9
10test: $(TARGET)
11	./$(TARGET)
12
13$(TARGET): $(OBJS)
14	$(CC) $(CFLAGS) $(OBJS) -o $(TARGET)
15
16%.o: %.c alloc.h
17	$(CC) $(CFLAGS) -c $< -o $@
18
19clean:
20	rm -f $(OBJS) $(TARGET)
21
22.PHONY: all test clean
23

steps: 20
duration: 49s
errors: 0
files: 4

session b2e47f91-007read this session →

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	claude-code	opencode	pi	antigravity
steps	51	45	44	20
tool calls	19	16	16	8
duration	12m 49s	2m 20s	2m 36s	49s
tokens out	154k	6k	2k	—
reasoning	—	—	~195	~2k
compactions	0	0	0	0
subagents	0	0	0	0
errors	10	0	4	0
files	4	4	4	4