Add Clang builds and CI testing for both GCC and Clang

- Makefile now builds with both GCC and Clang (C17 and C23)
- Detects real GCC vs Apple's clang alias on macOS
- CI runs separate jobs for GCC, Clang, and Zig on Ubuntu
- Updated benchmark script to test all 5 versions
- Updated BENCHMARK.md with comprehensive results

Author: vinitkumar

.github/workflows/zig.yml

@@ -7,7 +7,8 @@ on:
     branches: [ main, zig-port ]
 
 jobs:
-  c-build:
+  c-build-gcc:
+    name: C Build (GCC)
     runs-on: ubuntu-latest
 
     steps:
@@ -16,21 +17,45 @@ jobs:
     - name: Check GCC version
       run: gcc --version
 
-    - name: Build C versions (C17 and C23)
-      run: cd c && make clean && make
+    - name: Build with GCC (C17 and C23)
+      run: cd c && make clean && make gcc-builds
 
-    - name: Test C17 executable runs
-      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-c17 || true
+    - name: Test GCC C17 executable
+      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-gcc-c17 || true
 
-    - name: Test C23 executable runs
-      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-c23 || true
+    - name: Test GCC C23 executable
+      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-gcc-c23 || true
 
-    - name: Compare binary sizes
-      run: |
-        echo "Binary sizes:"
-        ls -lh c/chat-c17 c/chat-c23
+    - name: Show binary sizes
+      run: ls -lh c/chat-gcc-*
+
+  c-build-clang:
+    name: C Build (Clang)
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Install Clang
+      run: sudo apt-get update && sudo apt-get install -y clang
+    
+    - name: Check Clang version
+      run: clang --version
+    
+    - name: Build with Clang (C17 and C23)
+      run: cd c && make clean && make clang-builds
+    
+    - name: Test Clang C17 executable
+      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-clang-c17 || true
+    
+    - name: Test Clang C23 executable
+      run: cd c && echo -e "hi\npython\nexit" | timeout 5 ./chat-clang-c23 || true
+    
+    - name: Show binary sizes
+      run: ls -lh c/chat-clang-*
 
   zig-build-and-test:
+    name: Zig Build & Test
     runs-on: ubuntu-latest
 
     steps:

BENCHMARK.md

@@ -1,62 +1,82 @@
 # Chatbot Build & Runtime Benchmark Results
 
-Benchmark comparing C (C17 and C23 standards) and Zig implementations of the chatbot.
+Benchmark comparing C (GCC and Clang, C17 and C23 standards) and Zig implementations.
 
 **System:** macOS arm64  
 **Date:** 2026-01-12
 
-## Build Results
+## Compiler Versions (Local)
 
-| Metric | C17 | C23 | Zig | Notes |
-|--------|-----|-----|-----|-------|
-| Build Time | ~90ms | ~90ms | ~710ms | Zig ~8x slower |
-| Executable Size | 33K | 33K | 1.3M | Zig ~40x larger |
+| Compiler | Version |
+|----------|---------|
+| GCC (macOS) | Apple Clang 17.0.0 (gcc is aliased to clang) |
+| Clang | Homebrew Clang 21.1.8 |
+| Zig | 0.15.2 |
 
 ## Runtime Results
 
 | Version | Execution Time | Relative |
 |---------|---------------|----------|
-| C17 | 147ms | 1.00x |
-| C23 | 197ms | 1.34x |
-| Zig | 459ms | 3.12x |
+| GCC C17 | 228ms | 2.23x |
+| GCC C23 | 102ms | 1.00x (fastest) |
+| Clang C17 | 107ms | 1.04x |
+| Clang C23 | 106ms | 1.03x |
+| Zig | 628ms | 6.15x |
+
+## Binary Sizes
+
+| Version | Size |
+|---------|------|
+| GCC C17 | 33K |
+| GCC C23 | 33K |
+| Clang C17 | 33K |
+| Clang C23 | 33K |
+| Zig | 1.3M |
 
 ## Analysis
 
-### Build Time
-- **C (C17/C23)**: Fast compilation using GCC with minimal optimization
-- **Zig**: Longer compilation time due to more comprehensive compiler
+### C Compilers
+- **GCC C23** was fastest in this run (times vary between runs)
+- **Clang** produces consistently fast binaries across C17/C23
+- On macOS, `gcc` is actually Apple Clang; real GCC is tested on CI (Ubuntu)
 
-### Executable Size
-- **C (33K)**: Small, minimal runtime, links against system libc
-- **Zig (1.3M)**: Larger due to embedded standard library and runtime
-
-### Runtime Performance
-- **C17** is the fastest, likely due to mature compiler optimizations
-- **C23** is slightly slower (may vary based on compiler version)
-- **Zig** is slower due to:
+### Zig
+- Slower due to:
   - GeneralPurposeAllocator overhead vs C's stack allocation
-  - New Zig 0.15 buffered I/O system overhead
-  - Additional safety checks
+  - Zig 0.15 buffered I/O system overhead
+  - Additional runtime safety checks
+- Much larger binary (embeds stdlib, no libc dependency)
+
+### Binary Size
+- All C versions: 33K (links against system libc)
+- Zig: 1.3M (self-contained, no external dependencies)
 
 ## Build Configuration
 
-- **C17**: `gcc -std=c17 -Wall -Wextra -pedantic`
-- **C23**: `gcc -std=c23 -Wall -Wextra -pedantic` (falls back to `-std=c2x` on older compilers)
-- **Zig**: `zig build` (debug mode, Zig 0.15.2)
+| Compiler | Flags |
+|----------|-------|
+| GCC C17 | `gcc -std=c17 -Wall -Wextra -pedantic` |
+| GCC C23 | `gcc -std=c23 -Wall -Wextra -pedantic` |
+| Clang C17 | `clang -std=c17 -Wall -Wextra -pedantic` |
+| Clang C23 | `clang -std=c23 -Wall -Wextra -pedantic` |
+| Zig | `zig build` (debug mode) |
 
 ## Notes
 
 - All versions produce identical output
-- Times are from cold builds (no cache)
-- Runtime measured with same test input file
-- Zig uses pure Zig I/O (no libc linking)
+- C23 falls back to `-std=c2x` on older compilers
+- Times vary between runs; relative performance is more meaningful
+- CI tests both GCC and Clang on Ubuntu
 
 ## Running the Benchmarks
 
 ```bash
-# Full runtime benchmark
+# Full runtime benchmark (all compilers)
 ./run_benchmarks.sh
 
 # Build-only benchmark
 ./benchmark.sh
+
+# Show detected compilers
+cd c && make info
 ```

c/Makefile

@@ -1,19 +1,56 @@
-CC = gcc
+# Detect real GCC vs Apple's gcc alias
+UNAME_S := $(shell uname -s)
+ifeq ($(UNAME_S),Darwin)
+    # macOS: gcc is actually clang, use explicit paths if available
+    GCC := $(shell which gcc-14 gcc-13 gcc-12 2>/dev/null | head -1)
+    ifeq ($(GCC),)
+        GCC := gcc
+        GCC_NOTE := "(Apple Clang)"
+    endif
+else
+    GCC := gcc
+endif
+
+CLANG := clang
 CFLAGS_COMMON = -Wall -Wextra -pedantic
 SRC = src/chatbot.c
 
-all: chat-c17 chat-c23
+# Default targets
+all: gcc-builds clang-builds
+
+# GCC builds
+gcc-builds: chat-gcc-c17 chat-gcc-c23
+
+chat-gcc-c17:
+	$(GCC) -std=c17 $(CFLAGS_COMMON) $(SRC) -o chat-gcc-c17
+
+chat-gcc-c23:
+	$(GCC) -std=c23 $(CFLAGS_COMMON) $(SRC) -o chat-gcc-c23 2>/dev/null || \
+	$(GCC) -std=c2x $(CFLAGS_COMMON) $(SRC) -o chat-gcc-c23
 
-chat-c17:
-	$(CC) -std=c17 $(CFLAGS_COMMON) $(SRC) -o chat-c17
+# Clang builds
+clang-builds: chat-clang-c17 chat-clang-c23
 
-chat-c23:
-	$(CC) -std=c23 $(CFLAGS_COMMON) $(SRC) -o chat-c23 2>/dev/null || \
-	$(CC) -std=c2x $(CFLAGS_COMMON) $(SRC) -o chat-c23
+chat-clang-c17:
+	$(CLANG) -std=c17 $(CFLAGS_COMMON) $(SRC) -o chat-clang-c17
 
-# Legacy target for backwards compatibility
-chat: chat-c17
-	cp chat-c17 chat
+chat-clang-c23:
+	$(CLANG) -std=c23 $(CFLAGS_COMMON) $(SRC) -o chat-clang-c23 2>/dev/null || \
+	$(CLANG) -std=c2x $(CFLAGS_COMMON) $(SRC) -o chat-clang-c23
+
+# Legacy targets for backwards compatibility
+chat: chat-gcc-c17
+	cp chat-gcc-c17 chat
+
+chat-c17: chat-gcc-c17
+	cp chat-gcc-c17 chat-c17
+
+chat-c23: chat-gcc-c23
+	cp chat-gcc-c23 chat-c23
 
 clean:
-	rm -rf *.o chat chat-c17 chat-c23
+	rm -rf *.o chat chat-c17 chat-c23 chat-gcc-* chat-clang-*
+
+info:
+	@echo "GCC: $(GCC) $(GCC_NOTE)"
+	@echo "Clang: $(CLANG)"