70 lines
2.0 KiB
Markdown
70 lines
2.0 KiB
Markdown
# multiconf.make
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**multiconf.make** is a self-contained Makefile include that lets you build the **same targets under many different flag sets**—debug vs release, ASan vs UBSan, GCC vs Clang, etc.—without the usual “object-file soup.”
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It hashes every combination of `CC/CXX`, `CFLAGS/CXXFLAGS`, `CPPFLAGS`, `LDFLAGS` and `LDLIBS` into a **dedicated cache directory**, so objects compiled with one configuration are never reused by another. Swap flags, rebuild, swap back—previous objects are still there and never collide.
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---
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## Key Benefits
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| Why it matters | What multiconf.make does |
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| --- | --- |
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| **Isolated configs** | Stores objects into `cachedObjs/<hash>/`, one directory per unique flag set. |
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| **Fast switching** | Reusing an old config is instant—link only, no recompilation. |
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| **Header deps** | Edits to headers trigger only needed rebuilds. |
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| **One-liner targets** | Macros (`c_program`, `cxx_program`, …) hide all rule boilerplate. |
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| **Parallel-ready** | Safe with `make -j`, no duplicate compiles of shared sources. |
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---
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## Quick Start
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### 1 · List your sources
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```make
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C_SRCDIRS := src src/cdeps # all .c are in these directories
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CXX_SRCDIRS := src src/cxxdeps # all .cpp are in these directories
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```
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### 2 · Add and include
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```make
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# root/Makefile
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include multiconf.make
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```
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### 3 · Declare targets
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```make
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app:
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$(eval $(call c_program,app,app.o obj1.o obj2.o))
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test:
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$(eval $(call cxx_program,test, test.o objcxx1.o objcxx2.o))
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```
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### 4 · Build any config you like
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```sh
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# Release with GCC
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make CFLAGS="-O3"
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# Debug with Clang + AddressSanitizer (new cache dir)
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make CC=clang CFLAGS="-g -O0 -fsanitize=address"
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# Switch back to GCC release (objects still valid, relink only)
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make CFLAGS="-O3"
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```
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Objects for each command live in different sub-folders; nothing overlaps.
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---
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## Additional capabilities
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| Command | Description |
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| --- | --- |
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| `make clean_cache` | Wipe **all** cached objects & deps (full rebuild next time) |
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| `V=1` | Show full compile/link commands |
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---
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