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PATCH RFA: Add -static-libstdc++ option to g++
- From: Ian Lance Taylor <iant at google dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: edelsohn at gnu dot org
- Date: Fri, 19 Jun 2009 23:05:43 -0700
- Subject: PATCH RFA: Add -static-libstdc++ option to g++
It is sometimes useful to link statically against libstdc++ without
doing a full static link. In particular, when building gcc with C++,
I think this is what we want to do. We do not want to worry about
ensuring that gcc is able to find the right version of libstdc++ when
gcc itself is run.
This patch adds a -static-libstdc++ option to the g++ driver. This is
conceptually similar to the static-libgfortran option supported by the
gfortran driver.
I suppose this patch requires approval from the C++ frontend
maintainers. And/or, perhaps, the libstdc++ maintainers or the build
system maintainers. I'm not sure where this falls.
David, I adjusted your LIBSTDCXX_STATIC patch slightly: it now only
adds LIBSTDCXX_STATIC if it adds LIBSTDCXX. That seemed to me to be
the desired behaviour. Please let me know if this breaks anything.
Bootstrapped and ran C++ testsuite on x86_64-unknown-linux-gnu. OK
for mainline.
Ian
gcc/ChangeLog:
2009-06-19 Ian Lance Taylor <iant@google.com>
* doc/invoke.texi (Option Summary): Mention -static-libstdc++.
(Link Options): Document -static-libstdc++.
gcc/cp/ChangeLog:
2009-06-19 Ian Lance Taylor <iant@google.com>
* g++spec.c (SKIPOPT): define.
(lang_specific_driver): Handle -static-libstdc++. Only add
LIBSTDCXX_STATIC if we add LIBSTDCXX.
Index: cp/g++spec.c
===================================================================
--- cp/g++spec.c (revision 148727)
+++ cp/g++spec.c (working copy)
@@ -1,6 +1,6 @@
/* Specific flags and argument handling of the C++ front end.
Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
- 2007, 2008 Free Software Foundation, Inc.
+ 2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of GCC.
@@ -30,6 +30,8 @@ along with GCC; see the file COPYING3.
#define MATHLIB (1<<2)
/* This bit is set if they did `-lc'. */
#define WITHLIBC (1<<3)
+/* Skip this option. */
+#define SKIPOPT (1<<4)
#ifndef MATH_LIBRARY
#define MATH_LIBRARY "-lm"
@@ -63,7 +65,8 @@ lang_specific_driver (int *in_argc, cons
/* This is a tristate:
-1 means we should not link in libstdc++
0 means we should link in libstdc++ if it is needed
- 1 means libstdc++ is needed and should be linked in. */
+ 1 means libstdc++ is needed and should be linked in.
+ 2 means libstdc++ is needed and should be linked statically. */
int library = 0;
/* The number of arguments being added to what's in argv, other than
@@ -96,6 +99,9 @@ lang_specific_driver (int *in_argc, cons
/* By default, we throw on the math library if we have one. */
int need_math = (MATH_LIBRARY[0] != '\0');
+ /* True if we saw -static. */
+ int static_link = 0;
+
/* True if we should add -shared-libgcc to the command-line. */
int shared_libgcc = 1;
@@ -200,9 +206,15 @@ lang_specific_driver (int *in_argc, cons
cause a warning. */
library = -1;
}
- else if (strcmp (argv[i], "-static-libgcc") == 0
- || strcmp (argv[i], "-static") == 0)
+ else if (strcmp (argv[i], "-static") == 0)
+ static_link = 1;
+ else if (strcmp (argv[i], "-static-libgcc") == 0)
shared_libgcc = 0;
+ else if (strcmp (argv[i], "-static-libstdc++") == 0)
+ {
+ library = library >= 0 ? 2 : library;
+ args[i] |= SKIPOPT;
+ }
else if (DEFAULT_WORD_SWITCH_TAKES_ARG (&argv[i][1]))
i++;
else
@@ -261,7 +273,7 @@ lang_specific_driver (int *in_argc, cons
/* Make sure to have room for the trailing NULL argument.
Add one for shared_libgcc or extra static library. */
- num_args = argc + added + need_math + (library > 0) + 2;
+ num_args = argc + added + need_math + (library > 0) * 4 + 1;
arglist = XNEWVEC (const char *, num_args);
i = 0;
@@ -312,6 +324,9 @@ lang_specific_driver (int *in_argc, cons
arglist[j] = "-xnone";
}
+ if ((args[i] & SKIPOPT) != 0)
+ --j;
+
i++;
j++;
}
@@ -319,18 +334,32 @@ lang_specific_driver (int *in_argc, cons
/* Add `-lstdc++' if we haven't already done so. */
if (library > 0)
{
+#ifdef HAVE_LD_STATIC_DYNAMIC
+ if (library > 1 && !static_link)
+ {
+ arglist[j] = "-Wl,-Bstatic";
+ j++;
+ }
+#endif
arglist[j] = saw_profile_flag ? LIBSTDCXX_PROFILE : LIBSTDCXX;
if (arglist[j][0] != '-' || arglist[j][1] == 'l')
added_libraries++;
j++;
- }
- /* Add target-dependent static library, if necessary. */
- if (shared_libgcc == 0 && LIBSTDCXX_STATIC != NULL)
- {
- arglist[j] = LIBSTDCXX_STATIC;
- if (arglist[j][0] != '-' || arglist[j][1] == 'l')
- added_libraries++;
- j++;
+ /* Add target-dependent static library, if necessary. */
+ if ((static_link || library > 1) && LIBSTDCXX_STATIC != NULL)
+ {
+ arglist[j] = LIBSTDCXX_STATIC;
+ if (arglist[j][0] != '-' || arglist[j][1] == 'l')
+ added_libraries++;
+ j++;
+ }
+#ifdef HAVE_LD_STATIC_DYNAMIC
+ if (library > 1 && !static_link)
+ {
+ arglist[j] = "-Wl,-Bdynamic";
+ j++;
+ }
+#endif
}
if (saw_math)
arglist[j++] = saw_math;
@@ -343,7 +372,7 @@ lang_specific_driver (int *in_argc, cons
}
if (saw_libc)
arglist[j++] = saw_libc;
- if (shared_libgcc)
+ if (shared_libgcc && !static_link)
arglist[j++] = "-shared-libgcc";
arglist[j] = NULL;
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 148727)
+++ doc/invoke.texi (working copy)
@@ -409,7 +409,8 @@ Objective-C and Objective-C++ Dialects}.
@xref{Link Options,,Options for Linking}.
@gccoptlist{@var{object-file-name} -l@var{library} @gol
-nostartfiles -nodefaultlibs -nostdlib -pie -rdynamic @gol
--s -static -static-libgcc -shared -shared-libgcc -symbolic @gol
+-s -static -static-libgcc -static-libstdc++ -shared @gol
+-shared-libgcc -symbolic @gol
-T @var{script} -Wl,@var{option} -Xlinker @var{option} @gol
-u @var{symbol}}
@@ -8240,6 +8241,18 @@ for the languages used in the program, o
@option{-shared-libgcc}, such that it is linked with the shared
@file{libgcc}.
+@item -static-libstdc++
+When the @command{g++} program is used to link a C++ program, it will
+normally automatically link against @option{libstdc++}. If
+@file{libstdc++} is available as a shared library, and the
+@option{-static} option is not used, then this will link against the
+shared version of @file{libstdc++}. That is normally fine. However, it
+is sometimes useful to freeze the version of @file{libstdc++} used by
+the program without going all the way to a fully static link. The
+@option{-static-libstdc++} option directs the @command{g++} driver to
+link @file{libstdc++} statically, without necessarily linking other
+libraries statically.
+
@item -symbolic
@opindex symbolic
Bind references to global symbols when building a shared object. Warn