code review 1853041: Build libcgo.so with $(CC), not the gcc on PATH.

Build libcgo.so with $(CC), not the gcc on PATH.

Change make.bash to make sure that $(CC) is defined to match
the compiler used to build the tools.

[iant, 2010-07-15 09:02:02]

Hello rsc (cc: golang-dev@googlegroups.com),

I'd like you to review this change.

[r2, 2010-07-15 15:33:18]

LGTM

On Jul 15, 2010, at 2:02 AM, iant@golang.org wrote:

> Reviewers: rsc,
>
> Message:
> Hello rsc (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change.
>
>
> Description:
> Build libcgo.so with $(CC), not the gcc on PATH.
>
> Change make.bash to make sure that $(CC) is defined to match
> the compiler used to build the tools.
>
> Please review this at http://codereview.appspot.com/1853041/show
>
> Affected files:
>  M src/libcgo/Makefile
>  M src/make.bash
>
>
> Index: src/libcgo/Makefile
> ===================================================================
> --- a/src/libcgo/Makefile
> +++ b/src/libcgo/Makefile
> @@ -26,13 +26,13 @@
> LDFLAGS_windows=-shared -lm -mthreads
>
> %.o: %.c
> -	gcc $(CFLAGS_$(GOARCH)) -O2 -fPIC -o $@ -c $*.c
> +	$(CC) $(CFLAGS_$(GOARCH)) -O2 -fPIC -o $@ -c $*.c
>
> %.o: %.S
> -	gcc $(CFLAGS_$(GOARCH)) -O2 -fPIC -o $@ -c $*.S
> +	$(CC) $(CFLAGS_$(GOARCH)) -O2 -fPIC -o $@ -c $*.S
>
> libcgo.so: $(OFILES)
> -	gcc $(CFLAGS_$(GOARCH)) -o libcgo.so $(OFILES) $(LDFLAGS_$(GOOS))
> +	$(CC) $(CFLAGS_$(GOARCH)) -o libcgo.so $(OFILES) $(LDFLAGS_$(GOOS))
>
> $(QUOTED_GOROOT)/pkg/$(GOOS)_$(GOARCH)/libcgo.so: libcgo.so
> 	cp libcgo.so $(QUOTED_GOROOT)/pkg/$(GOOS)_$(GOARCH)
> Index: src/make.bash
> ===================================================================
> --- a/src/make.bash
> +++ b/src/make.bash
> @@ -12,6 +12,7 @@
>
> rm -f "$GOBIN"/quietgcc
> CC=${CC:-gcc}
> +export CC
> sed -e "s|@CC@|$CC|" < "$GOROOT"/src/q

[rsc, 2010-07-15 16:26:14]

LGTM

[rsc, 2010-07-15 16:26:37]

Actually, wait.

cgo invokes gcc directly as gcc.  What do we do for that?

[iant2, 2010-07-15 19:31:25]

Russ Cox <rsc@golang.org> writes:

> Actually, wait.
>
> cgo invokes gcc directly as gcc.  What do we do for that?

Two choices:

1) Bake the value of $(CC) at build time into cgo.

2) Within cgo, use $CC if it set in the environment, otherwise use gcc.

I think choice 2 is right.  It means that the right thing will happen
when cgo is invoked from a Makefile.

Ian

[rsc, 2010-07-15 19:34:46]

okay; 2 LGTM

[iant, 2010-07-15 21:15:47]

*** Submitted as http://code.google.com/p/go/source/detail?r=d5fef2bba1e7 ***

Build libcgo.so with $(CC), not the gcc on PATH.

Change make.bash to make sure that $(CC) is defined to match
the compiler used to build the tools.

R=rsc
CC=golang-dev
http://codereview.appspot.com/1853041