build: isolate build-info defines into utils/buildinfo.c (ccache-friendly)

MAGIC_VERSION / MAGIC_REVISION / MAGIC_COMMIT / MAGIC_BUILDDATE were on the
global DFLAGS, so every object's compile command line carried them.  Because
the command line is part of ccache/sccache's hash key and MAGIC_BUILDDATE
changes every second, that meant a cache miss on every unit on every build;
it also smeared the baked-in date/commit across "whenever each file last
recompiled".

Move the four values into a single translation unit:
  * utils/magic_buildinfo.h -- extern MagicVersion/MagicRevision/MagicCommit/
    MagicCompileTime (MagicCommit is new; the other three moved here from
    utils/magic.h, which now includes this header).
  * utils/buildinfo.c -- the ONLY unit compiled with the version defines
    (target-specific `buildinfo.o: DFLAGS += ${DFLAGS_MAGICVERSION}` in
    utils/Makefile.in); it defines the four globals.  ${DFLAGS_MAGICVERSION}
    is removed from the global DFLAGS/DFLAGS_NOSTUB.

Consumers updated to read the runtime symbol instead of the compile-time
macro:
  * magicTop.c / tclmagic.c no longer define the globals (the MAGIC_WRAPPER
    duplicate-symbol guard is gone -- buildinfo.o owns them for every variant,
    including WASM, which links both mains).
  * Tcl_PkgProvide/PkgRequire in router/ext2spice/lef/ext2sim/plot/tclmagic
    now pass MagicVersion.
  * extflat: EFVersion (a static-initialized copy of MAGIC_VERSION) is dropped;
    EFread.c compares the .ext version against MagicVersion directly -- the same
    value ExtCell.c already *writes* into .ext files, so read and write are now
    consistent.

Verified: only buildinfo.o carries -DMAGIC_* (hash/DBio/windCmdSZ carry none);
Tcl (375 files) and --without-tcl builds rc=0, version/commit/date embedded in
tclmagic.so, magicTop.o no longer defines MagicVersion; in-tree source clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ext2sim/ext2sim.c

@@ -208,7 +208,7 @@ Exttosim_Init(
 {
     /* Sanity checks! */
     if (interp == NULL) return TCL_ERROR;
-    if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
+    if (Tcl_PkgRequire(interp, "Tclmagic", MagicVersion, 0) == NULL)
 	return TCL_ERROR;
     if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
@@ -225,7 +225,7 @@ Exttosim_Init(
     if (WindReplaceCommand(DBWclientID, "ext2sim", CmdExtToSim) < 0)
 	return TCL_ERROR;
 
-    Tcl_PkgProvide(interp, "Exttosim", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "Exttosim", MagicVersion);
     return TCL_OK;
 }
 

ext2spice/ext2spice.c

@@ -206,7 +206,7 @@ Exttospice_Init(
 {
     /* Sanity checks! */
     if (interp == NULL) return TCL_ERROR;
-    if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
+    if (Tcl_PkgRequire(interp, "Tclmagic", MagicVersion, 0) == NULL)
 	return TCL_ERROR;
     if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
@@ -223,7 +223,7 @@ Exttospice_Init(
     if (WindReplaceCommand(DBWclientID, "ext2spice", CmdExtToSpice) < 0)
 	return TCL_ERROR;
 
-    Tcl_PkgProvide(interp, "Exttospice", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "Exttospice", MagicVersion);
     return TCL_OK;
 }
 #endif /* EXT2SPICE_AUTO */

extflat/EFargs.c

@@ -52,7 +52,6 @@ char *EFArgTech = NULL;		/* -T: Tech specified on command line */
 
     /* Misc globals */
 float EFScale = 0.0;		/* Uninitialized scale factor */
-char *EFVersion = MAGIC_VERSION;/* Version number of .ext format we read */
 char *EFLibPath = NULL;		/* Library search path for .ext files */
 char *EFTech = NULL;
 char *EFStyle = NULL;		/* Start with no extraction style */

extflat/EFread.c

@@ -575,7 +575,7 @@ resistChanged:
 
 	    /* version version-number */
 	    case VERSION:
-		if (strcmp(argv[1], EFVersion) != 0)
+		if (strcmp(argv[1], MagicVersion) != 0)
 		{
 		    efReadError(
 	"Cell was extracted using version %s of the extractor.\n", argv[1]);

extflat/extflat.h

@@ -32,7 +32,6 @@ extern char *EFTech;		/* Technology of extracted circuit */
 extern char *EFStyle;           /* Extraction style of extracted circuit */
 extern char *EFSearchPath;	/* Path to search for .ext files */
 extern char *EFLibPath;		/* Library search path */
-extern char *EFVersion;		/* Version of extractor we work with */
 extern char *EFArgTech;		/* Tech file given as command line argument */
 extern bool  EFCompat;		/* Subtrate backwards-compatibility mode */
 

lef/tcllef.c

@@ -41,7 +41,7 @@ Magiclef_Init(
 {
     /* Sanity checks! */
     if (interp == NULL) return TCL_ERROR;
-    if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
+    if (Tcl_PkgRequire(interp, "Tclmagic", MagicVersion, 0) == NULL)
 	return TCL_ERROR;
     if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
@@ -57,7 +57,7 @@ Magiclef_Init(
     if (WindReplaceCommand(DBWclientID, "def", CmdLef) < 0)
 	return TCL_ERROR;
 
-    Tcl_PkgProvide(interp, "MagicLEF", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "MagicLEF", MagicVersion);
     return TCL_OK;
 }
 

magic/magicTop.c

@@ -55,18 +55,10 @@ main(int argc, char *argv[])
     exit(0);
 }
 
-/* String containing the version number of magic.  Don't change the string
+/* MagicVersion / MagicRevision / MagicCompileTime are defined once in
- * here, nor its format.  It is updated by the Makefile in this directory.
+ * utils/buildinfo.c -- the single unit compiled with the version defines --
- *
+ * and declared in utils/magic_buildinfo.h.  They used to be defined here (and,
- * The version string originates at the top of scripts/config.
+ * for the Tcl build, in tclmagic.c under a MAGIC_WRAPPER guard); consolidating
- *
+ * them removes the duplicate-symbol hazard and keeps the volatile build-date
- * Under MAGIC_WRAPPER (Tcl-embedded builds), tclmagic.c owns these globals;
+ * define off every compile command line.
- * defining them here as well would produce duplicate-symbol errors when both
- * objects end up in the same binary (as in the WASM build).
  */
-
-#ifndef MAGIC_WRAPPER
-char *MagicVersion = MAGIC_VERSION;
-char *MagicRevision = MAGIC_REVISION;
-char *MagicCompileTime = MAGIC_BUILDDATE;
-#endif

plot/tclplot.c

@@ -44,7 +44,7 @@ Tclplot_Init(interp)
 
     /* Sanity checks! */
     if (interp == NULL) return TCL_ERROR;
-    if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
+    if (Tcl_PkgRequire(interp, "Tclmagic", MagicVersion, 0) == NULL)
 	return TCL_ERROR;
     if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
@@ -67,7 +67,7 @@ Tclplot_Init(interp)
     invplot = TechSectionGetMask("plot", NULL);
     if (!TechLoad(NULL, invplot)) return TCL_ERROR;
 
-    Tcl_PkgProvide(interp, "Plot", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "Plot", MagicVersion);
     return TCL_OK;
 }
 

router/tclroute.c

@@ -51,7 +51,7 @@ Tclroute_Init(interp)
 
     /* Sanity checks! */
     if (interp == NULL) return TCL_ERROR;
-    if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
+    if (Tcl_PkgRequire(interp, "Tclmagic", MagicVersion, 0) == NULL)
 	return TCL_ERROR;
     if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
@@ -88,7 +88,7 @@ Tclroute_Init(interp)
     invsec &= TechSectionGetMask("router", NULL);
     if (!TechLoad(NULL, invsec)) return TCL_ERROR;
 
-    Tcl_PkgProvide(interp, "Route", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "Route", MagicVersion);
     return TCL_OK;
 }
 

scripts/defs.mak.in

@@ -163,9 +163,9 @@ ifeq (@MAKE_READLINE@,1)
 CPPFLAGS              += -I${MAGICSRC}/readline
 endif
 DFLAGS_MAGICVERSION    = -DMAGIC_VERSION=\"${MAGIC_VERSION}\" -DMAGIC_REVISION=\"${MAGIC_REVISION}\" -DMAGIC_COMMIT=\"${MAGIC_COMMIT}\" "-DMAGIC_BUILDDATE=\"${MAGIC_BUILDDATE}\""
-DFLAGS                 = @extra_defs@ @stub_defs@ @DEFS@ ${DFLAGS_MAGICVERSION} -DGCORE=\"@GCORE@\"
+DFLAGS                 = @extra_defs@ @stub_defs@ @DEFS@ -DGCORE=\"@GCORE@\"
 DFLAGS		      += -DSHDLIB_EXT=\"@SHDLIB_EXT@\" @NDEBUG_defs@ @DEBUG_defs@ ${FEATURE_FLAGS}
-DFLAGS_NOSTUB	       = @extra_defs@             @DEFS@ ${DFLAGS_MAGICVERSION} -DGCORE=\"@GCORE@\"
+DFLAGS_NOSTUB	       = @extra_defs@             @DEFS@ -DGCORE=\"@GCORE@\"
 DFLAGS_NOSTUB	      += -DSHDLIB_EXT=\"@SHDLIB_EXT@\" @NDEBUG_defs@ @DEBUG_defs@ ${FEATURE_FLAGS}
 CFLAGS                 = @CFLAGS@ @SHLIB_CFLAGS@ @INC_SPECS@
 

tcltk/tclmagic.c

@@ -48,14 +48,11 @@
 #include "dbwind/dbwind.h"
 
 /*
- * String containing the version number of magic.  Don't change the string
+ * MagicVersion / MagicRevision / MagicCompileTime are defined once in
- * here, nor its format.  It is updated by the Makefile in this directory.
+ * utils/buildinfo.c and declared in utils/magic_buildinfo.h (included via
+ * utils/magic.h).  They no longer need a MAGIC_WRAPPER-guarded definition here.
  */
 
-char *MagicVersion = MAGIC_VERSION;
-char *MagicRevision = MAGIC_REVISION;
-char *MagicCompileTime = MAGIC_BUILDDATE;
-
 #if TCL_MAJOR_VERSION < 9
 const char *Tclmagic_InitStubsVersion = "8.5";
 #else
@@ -1546,7 +1543,7 @@ Tclmagic_Init(interp)
 	Tcl_SetVar(interp, "CAD_ROOT", cadroot, TCL_GLOBAL_ONLY);
     }
 
-    Tcl_PkgProvide(interp, "Tclmagic", MAGIC_VERSION);
+    Tcl_PkgProvide(interp, "Tclmagic", MagicVersion);
     return TCL_OK;
 }
 

utils/Makefile.in

@@ -9,7 +9,7 @@ srcdir    = @srcdir@
 VPATH     = @srcdir@
 MAGICDIR  = @top_builddir@
 LIB_SRCS  = LIBdbio.c LIBmain.c LIBtextio.c
-SRCS      = args.c child.c dqueue.c finddisp.c flock.c flsbuf.c fraction.c \
+SRCS      = args.c buildinfo.c child.c dqueue.c finddisp.c flock.c flsbuf.c fraction.c \
             geometry.c getrect.c hash.c heap.c ihash.c list.c lookup.c \
 	    lookupany.c lookupfull.c macros.c main.c malloc.c match.c \
 	    maxrect.c netlist.c niceabort.c parser.c path.c pathvisit.c \
@@ -23,3 +23,9 @@ DFLAGS += ${GR_DFLAGS}
 CFLAGS += ${GR_CFLAGS}
 
 include ${MAGICSRC}/rules.mak
+
+# buildinfo.c is the ONLY unit that consumes the version defines; they are no
+# longer on the global DFLAGS (that kept the ever-changing MAGIC_BUILDDATE off
+# every other compile command line, so ccache/sccache keys stay stable).  Apply
+# them just here, target-specifically.
+buildinfo.o: DFLAGS += ${DFLAGS_MAGICVERSION}

utils/buildinfo.c

@@ -0,0 +1,31 @@
+/*
+ * buildinfo.c --
+ *
+ * The single translation unit that captures the build-information defines.
+ *
+ * This is the ONLY file compiled with -DMAGIC_VERSION / -DMAGIC_REVISION /
+ * -DMAGIC_COMMIT / -DMAGIC_BUILDDATE (see the buildinfo.o recipe in
+ * utils/Makefile.in).  Isolating them here keeps those defines -- especially the
+ * ever-changing MAGIC_BUILDDATE -- off every other compile command line, so
+ * ccache/sccache keys stay stable and the version/date/commit baked into the
+ * binary are consistent rather than smeared across whenever each object last
+ * recompiled.
+ *
+ * Consumers include "utils/magic_buildinfo.h" and read these externs.
+ */
+
+#include "utils/magic_buildinfo.h"
+
+char *MagicVersion = MAGIC_VERSION;
+char *MagicRevision = MAGIC_REVISION;
+char *MagicCommit = MAGIC_COMMIT;
+
+/*
+ * MAGIC_BUILDDATE may be disabled at configure time (--disable-magic-builddate)
+ * for reproducible builds; when it is, MagicCompileTime reports the empty string.
+ */
+#ifdef MAGIC_NO_BUILDDATE
+char *MagicCompileTime = "";
+#else
+char *MagicCompileTime = MAGIC_BUILDDATE;
+#endif

utils/magic.h

@@ -145,9 +145,10 @@ extern char *SysLibPath;	/* Path for finding system
 
 /* ------------ Globally-used strings. -------------------------------- */
 
-extern char *MagicVersion;
+/* Build-info globals (MagicVersion / MagicRevision / MagicCommit /
-extern char *MagicRevision;
+ * MagicCompileTime) are defined in utils/buildinfo.c -- the one unit compiled
-extern char *MagicCompileTime;
+ * with the version defines -- and declared here: */
+#include "utils/magic_buildinfo.h"
 extern char AbortMessage[];
 
 /* ------------ zlib (compression) support -------------------------------- */

utils/magic_buildinfo.h

@@ -0,0 +1,24 @@
+/*
+ * magic_buildinfo.h --
+ *
+ * Public declarations for the build-information globals: magic's version,
+ * revision, git commit, and compile date/time.
+ *
+ * These are the ONLY symbols initialized from the -DMAGIC_VERSION /
+ * -DMAGIC_REVISION / -DMAGIC_COMMIT / -DMAGIC_BUILDDATE command-line defines.
+ * They are defined in exactly one translation unit, utils/buildinfo.c, which is
+ * the only unit compiled with those defines.  Every other unit reads the values
+ * through these externs, so the volatile build-date/commit values stay off every
+ * other compile command line (which keeps ccache/sccache keys stable and the
+ * baked-in date/commit consistent across the whole binary).
+ */
+
+#ifndef _MAGIC_BUILDINFO_H
+#define _MAGIC_BUILDINFO_H
+
+extern char *MagicVersion;	/* e.g. "8.3"  (major.minor) */
+extern char *MagicRevision;	/* e.g. "670"  (patch/revision) */
+extern char *MagicCommit;	/* git commit SHA, or "" if unavailable */
+extern char *MagicCompileTime;	/* build date/time, or "" if disabled */
+
+#endif /* _MAGIC_BUILDINFO_H */