runtime: add GOROOT and Version

R=r
CC=golang-dev
https://golang.org/cl/608041

.hgignore

@@ -26,9 +26,13 @@ src/cmd/gc/yerr.h
 src/pkg/Make.deps
 src/pkg/exp/ogle/ogle
 src/pkg/os/signal/unix.go
-src/pkg/runtime/cgo2c
 src/pkg/runtime/*/asm.h
+src/pkg/runtime/cgo2c
+src/pkg/runtime/mkversion
 src/pkg/runtime/runtime.acid.*
+src/pkg/runtime/version.go
+src/pkg/github.com/
+src/pkg/*.googlecode.com/
 test/pass.out
 test/run.out
 test/times.out

src/pkg/runtime/Makefile

@@ -23,6 +23,7 @@ CFLAGS=-I$(GOOS) -I$(GOOS)/$(GOARCH) -wF $(CFLAGS_$(SIZE)) $(CFLAGS_$(GOARCH)) $
 GOFILES=\
 	extern.go\
 	type.go\
+	version.go\
 
 GOFILES_pchw=\
 	pchw/io.go\
@@ -111,7 +112,7 @@ $(pkgdir)/%.h: %.h
 clean: clean-local
 
 clean-local:
-	rm -f cgo2c */asm.h runtime.acid.*
+	rm -f cgo2c mkversion version.go */asm.h runtime.acid.*
 
 $(GOARCH)/asm.h: mkasmh.sh runtime.acid.$(GOARCH)
 	./mkasmh.sh >$@.x
@@ -120,6 +121,12 @@ $(GOARCH)/asm.h: mkasmh.sh runtime.acid.$(GOARCH)
 cgo2c: cgo2c.c
 	$(QUOTED_GOBIN)/quietgcc -o $@ $<
 
+mkversion: mkversion.c
+	$(QUOTED_GOBIN)/quietgcc -o $@ -I "$(GOROOT)/include" $< "$(GOROOT)/lib/lib9.a"
+
+version.go: mkversion
+	mkversion >version.go
+
 %.c:	%.cgo cgo2c
 	./cgo2c $< > $@.tmp
 	mv -f $@.tmp $@

src/pkg/runtime/extern.go

@@ -150,3 +150,23 @@ func GC()
 // TODO(rsc): allow f to have (ignored) return values
 //
 func SetFinalizer(x, f interface{})
+
+func getgoroot() string
+
+// GOROOT returns the root of the Go tree.
+// It uses the GOROOT environment variable, if set,
+// or else the root used during the Go build.
+func GOROOT() string {
+	s := getgoroot()
+	if s != "" {
+		return s
+	}
+	return defaultGoroot
+}
+
+// Version returns the Go tree's version string.
+// It is either a sequence number or, when possible,
+// a release tag like "release.2010-03-04".
+// A trailing + indicates that the tree had local modifications
+// at the time of the build.
+func Version() string { return defaultVersion }

src/pkg/runtime/mkversion.c

+#include <u.h>
+#include <libc.h>
+
+char *template =
+	"// generated by mkversion.c; do not edit.\n"
+	"package runtime\n"
+	"const defaultGoroot = \"%s\"\n"
+	"const defaultVersion = \"%s\"\n";
+
+void
+main(void)
+{
+	print(template, getgoroot(), getgoversion());
+	exits(0);
+}

src/pkg/runtime/runtime.c

@@ -206,6 +206,15 @@ getenv(int8 *s)
 	return nil;
 }
 
+void
+·getgoroot(String out)
+{
+	byte *p;
+	
+	p = getenv("GOROOT");
+	out = gostring(p);
+	FLUSH(&out);
+}
 
 int32
 atoi(byte *p)