From 7a68070bac9392ea73266abce67ef899f6d2262e Mon Sep 17 00:00:00 2001
From: Lephe <sebastien.michelland@protonmail.com>
Date: Wed, 4 Nov 2020 22:12:01 +0100
Subject: [PATCH] show version in header for static version resolution

This change moves the gint version declaration from a symbol in a
compile-time generated object file to a preprocessed header installed in
the library tree.

This makes it possible to determine the gint version statically from the
headers, which is much more robust in complex build systems that use
version information such as CMake's find_package().
---
 include/gint/config.h.in | 19 +++++++++++++++++++
 include/gint/gint.h      | 10 +---------
 make/Makefile            | 26 ++++++++++++++------------
 3 files changed, 34 insertions(+), 21 deletions(-)
 create mode 100644 include/gint/config.h.in

diff --git a/include/gint/config.h.in b/include/gint/config.h.in
new file mode 100644
index 0000000..6d8b414
--- /dev/null
+++ b/include/gint/config.h.in
@@ -0,0 +1,19 @@
+//---
+//	config - Compile-time generate configuration
+//---
+
+#ifndef GINT_CONFIG
+#define GINT_CONFIG
+
+#include <gint/defs/types.h>
+
+/* GINT_VERSION: Latest tag and number of additional commits
+     "2.1.0"   = Release 2.1.0
+     "2.1.1-5" = 5 commits after release 2.1.1 */
+#define GINT_VERSION @GINT_VERSION@
+
+/* GINT_HASH: Commit hash with 7 digits
+     0x03f7c0a0 = Commit 3f7c0a0 */
+#define GINT_HASH @GINT_HASH@
+
+#endif /* GINT_CONFIG */
diff --git a/include/gint/gint.h b/include/gint/gint.h
index e086e4b..5d041e2 100644
--- a/include/gint/gint.h
+++ b/include/gint/gint.h
@@ -6,15 +6,7 @@
 #define GINT_GINT
 
 #include <gint/defs/types.h>
-
-/* GINT_VERSION - the library version number
-
-   gint is versioned from its repository commits on the master branch. The
-   GINT_VERSION integer contains the short commit hash with 7 digits.
-
-   For instance, 0x03f7c0a0 means commit 3f7c0a0. */
-extern char GINT_VERSION;
-#define GINT_VERSION ((uint32_t)&GINT_VERSION)
+#include <gint/config.h>
 
 /* gint_switch(): Switch out of gint to execute a function
 
diff --git a/make/Makefile b/make/Makefile
index 70a4e7d..40a34e8 100755
--- a/make/Makefile
+++ b/make/Makefile
@@ -26,7 +26,7 @@ machine ?= -m4-nofpu -mb
 endif
 
 # Compiler flags, assembler flags, dependency generation, archiving
-inc     := -I ../include
+inc     := -I ../include -I include
 cflags  := $(machine) -ffreestanding -nostdlib -Wall -Wextra -std=c11 -Os \
            -fstrict-volatile-bitfields $(inc) $(CONFIG.MACROS) \
            $(CONFIG.CFLAGS)
@@ -64,7 +64,7 @@ src_obj  := $(foreach s,$(src),$(call src2obj,$s))
 # Files with special handling
 spe-fx  := ../src/font5x7.png
 spe-cg  := ../src/font8x9.png
-spe_obj := version.o $(foreach s,$(spe-$(CONFIG.TARGET)),$(call src2obj,$s))
+spe_obj := $(foreach s,$(spe-$(CONFIG.TARGET)),$(call src2obj,$s))
 
 # All object files
 obj := $(src_obj) $(spe_obj)
@@ -87,6 +87,8 @@ objcopy	= $(CONFIG.TOOLCHAIN)-objcopy
 
 # Version symbol is obtained by using the last commit hash on 7 nibbles
 version_hash = 0x0$(shell git rev-parse --short HEAD)
+# Version number: closest tag, with additional commits
+version_number = $(shell git describe --tag --always | cut -d- -f1-2)
 
 
 #
@@ -95,7 +97,7 @@ version_hash = 0x0$(shell git rev-parse --short HEAD)
 
 all: $(target)
 
-$(target): $(obj)
+$(target): include/gint/config.h $(obj)
 	@ rm -f $@
 	$(call cmd_l,ar,$@) $(ar) rcs $(arflags) $@ $^
 
@@ -113,6 +115,11 @@ src/%.c.o: ../src/%.c src/%.c.d
 	$(call cmd_b,gcc,$*.c) $(gcc) -c $< -o $@ $(dflags) $(cflags)
 
 # Special files
+include/gint/config.h: ../include/gint/config.h.in $(gitfile)
+	@ mkdir -p $(dir $@)
+	$(call cmd_m,sed,$@) cp $< $@
+	@ sed -i'' 's/@GINT_VERSION@/"$(version_number)"/' $@
+	@ sed -i'' 's/@GINT_HASH@/$(version_hash)/' $@
 $(call src2obj,../src/font5x7.png): ../src/font5x7.png
 	@ mkdir -p $(dir $@)
 	$(call cmd_m,fxconv,font5x7.png) fxconv -f $< -o $@ \
@@ -125,19 +132,12 @@ $(call src2obj,../src/font8x9.png): ../src/font8x9.png
 		charset:print grid.size:8x11 grid.padding:1 grid.border:0 \
 		proportional:true height:9
 
-# Version symbol. ld generates a .stack section for unknown reasons; I remove
-# it in the linker script.
-version.o: $(gitfile)
-	@ mkdir -p $(dir $@)
-	@ echo "_GINT_VERSION = $(version_hash);" > $@.txt
-	$(call cmd_b,ld,$@) $(ld) -r -R $@.txt -o $@
-
 #
 #  Cleaning
 #
 
 clean:
-	@ rm -rf src version.o{,txt}
+	@ rm -rf src include
 distclean: clean
 	@ rm -rf Makefile $(CONFIG) $(target)
 
@@ -156,7 +156,9 @@ install: $(target)
 	install -d $(PREFIX)
 	install $(target) $(m644) $(PREFIX)
 	install ../$(CONFIG.TARGET.LONG).ld $(m644) $(PREFIX)
-	cp -r ../include/gint $(PREFIX)/include
+	install -d $(PREFIX)/include/gint
+	cp ../include/gint/*.h $(PREFIX)/include/gint/
+	cp include/gint/*.h $(PREFIX)/include/gint/
 
 uninstall:
 	rm -f $(PREFIX)/$(target)