Build System Parity
This document explains how to achieve identical builds between fpm and Makefile.
TL;DR
For identical optimized builds:
# Using fpm
fpm build --flag "-O2 -Wall -ffree-line-length-none"
# Using make
make
# Or use the unified build script
./build.sh release
Build Systems
facsimile supports two build systems:
- fpm (Fortran Package Manager) - Modern, dependency-aware
- Makefile - Traditional, platform-specific optimizations
Key Differences
| Aspect | fpm | Makefile |
|---|---|---|
| Dependency Management | Automatic | Manual (order matters) |
| Parallel Build | Safe, automatic | Disabled (.NOTPARALLEL) |
| Compiler Selection | Uses PATH gfortran | Detects Homebrew gfortran on macOS |
| Output Location | ./build/gfortran_*/app/fac |
./fac |
| Incremental Builds | Efficient | Basic |
| C Code Handling | Automatic | Explicit gcc compilation |
Compiler Flags
Both systems use the same optimization flags for release builds:
-O2- Optimization level 2 (good balance of speed and size)-Wall- Enable all warnings-ffree-line-length-none- Allow long Fortran lines
Binary Size Comparison
With identical flags, both systems produce nearly identical binaries:
- Makefile build: ~287KB
- fpm optimized build: ~294KB
The slight difference (~7KB) is due to:
- Different linking order
- Metadata differences
- Path information
Platform-Specific Notes
macOS (Apple Silicon)
- Makefile automatically finds Homebrew's gfortran in
/opt/homebrew - fpm uses whatever gfortran is in PATH
- Ensure Homebrew's gfortran is in PATH for consistency
Linux
- Both systems work identically
- No special configuration needed
Debug Builds
# fpm debug build
fpm build --flag "-g -Wall -ffree-line-length-none -fbacktrace -fcheck=bounds"
# Makefile doesn't have debug configuration
# Edit FFLAGS manually if needed
Recommendations
- For Development: Use fpm (better incremental builds)
- For Distribution:
- macOS: Use Makefile (better compiler detection)
- Linux: Either works fine
- For CI/CD: Use fpm with explicit flags
Build Script
Use the provided build.sh script for unified building:
./build.sh release # Optimized build
./build.sh debug # Debug build (fpm only)
./build.sh clean # Clean build artifacts
The script automatically detects available build systems and uses appropriate flags for parity.
View source
| 1 | # Build System Parity |
| 2 | |
| 3 | This document explains how to achieve identical builds between fpm and Makefile. |
| 4 | |
| 5 | ## TL;DR |
| 6 | |
| 7 | For identical optimized builds: |
| 8 | |
| 9 | ```bash |
| 10 | # Using fpm |
| 11 | fpm build --flag "-O2 -Wall -ffree-line-length-none" |
| 12 | |
| 13 | # Using make |
| 14 | make |
| 15 | |
| 16 | # Or use the unified build script |
| 17 | ./build.sh release |
| 18 | ``` |
| 19 | |
| 20 | ## Build Systems |
| 21 | |
| 22 | facsimile supports two build systems: |
| 23 | |
| 24 | 1. **fpm** (Fortran Package Manager) - Modern, dependency-aware |
| 25 | 2. **Makefile** - Traditional, platform-specific optimizations |
| 26 | |
| 27 | ## Key Differences |
| 28 | |
| 29 | | Aspect | fpm | Makefile | |
| 30 | |--------|-----|----------| |
| 31 | | Dependency Management | Automatic | Manual (order matters) | |
| 32 | | Parallel Build | Safe, automatic | Disabled (.NOTPARALLEL) | |
| 33 | | Compiler Selection | Uses PATH gfortran | Detects Homebrew gfortran on macOS | |
| 34 | | Output Location | `./build/gfortran_*/app/fac` | `./fac` | |
| 35 | | Incremental Builds | Efficient | Basic | |
| 36 | | C Code Handling | Automatic | Explicit gcc compilation | |
| 37 | |
| 38 | ## Compiler Flags |
| 39 | |
| 40 | Both systems use the same optimization flags for release builds: |
| 41 | |
| 42 | - `-O2` - Optimization level 2 (good balance of speed and size) |
| 43 | - `-Wall` - Enable all warnings |
| 44 | - `-ffree-line-length-none` - Allow long Fortran lines |
| 45 | |
| 46 | ## Binary Size Comparison |
| 47 | |
| 48 | With identical flags, both systems produce nearly identical binaries: |
| 49 | |
| 50 | - Makefile build: ~287KB |
| 51 | - fpm optimized build: ~294KB |
| 52 | |
| 53 | The slight difference (~7KB) is due to: |
| 54 | - Different linking order |
| 55 | - Metadata differences |
| 56 | - Path information |
| 57 | |
| 58 | ## Platform-Specific Notes |
| 59 | |
| 60 | ### macOS (Apple Silicon) |
| 61 | - Makefile automatically finds Homebrew's gfortran in `/opt/homebrew` |
| 62 | - fpm uses whatever gfortran is in PATH |
| 63 | - Ensure Homebrew's gfortran is in PATH for consistency |
| 64 | |
| 65 | ### Linux |
| 66 | - Both systems work identically |
| 67 | - No special configuration needed |
| 68 | |
| 69 | ## Debug Builds |
| 70 | |
| 71 | ```bash |
| 72 | # fpm debug build |
| 73 | fpm build --flag "-g -Wall -ffree-line-length-none -fbacktrace -fcheck=bounds" |
| 74 | |
| 75 | # Makefile doesn't have debug configuration |
| 76 | # Edit FFLAGS manually if needed |
| 77 | ``` |
| 78 | |
| 79 | ## Recommendations |
| 80 | |
| 81 | 1. **For Development**: Use fpm (better incremental builds) |
| 82 | 2. **For Distribution**: |
| 83 | - macOS: Use Makefile (better compiler detection) |
| 84 | - Linux: Either works fine |
| 85 | 3. **For CI/CD**: Use fpm with explicit flags |
| 86 | |
| 87 | ## Build Script |
| 88 | |
| 89 | Use the provided `build.sh` script for unified building: |
| 90 | |
| 91 | ```bash |
| 92 | ./build.sh release # Optimized build |
| 93 | ./build.sh debug # Debug build (fpm only) |
| 94 | ./build.sh clean # Clean build artifacts |
| 95 | ``` |
| 96 | |
| 97 | The script automatically detects available build systems and uses appropriate flags for parity. |