The setup:
Configuring a toolchain targeting x86-64 GNU Linux (Ubuntu Lucid), as a
cross-compiler. Using a sysroot to provide the Lucid headers+libraries,
with the sysroot path being within the GCC install tree. Want to use the
Lucid system libstdc++ and headers, which means that I'm not
building/installing libstdc++-v3.
So, configuring with:
--with-sysroot="$SYSROOT"
--disable-libstdc++-v3 \
--with-gxx-include-dir="$SYSROOT/usr/include/c++/4.4" \
(among other options).
Hoping to support two usage models with this configuration, w.r.t. use of
the sysroot:
(1) somebody installs the sysroot in the normal location relative to the
GCC install, and relocates the whole bundle (sysroot+GCC). This works
great AFAICT, GCC finds its includes (including the C++ includes) thanks
to the add_standard_paths iprefix handling.
(2) somebody installs the sysroot in a non-standard location, and uses
--sysroot to try to access it. This works fine for the C headers, but
doesn't work.
For the C headers, add_standard_paths prepends the sysroot location to
the /usr/include path (since that's what's specified in cppdefault.c for
that path). It doesn't do the same for the C++ include path, though
(again, as specified in cppdefault.c).
add_standard_paths doesn't attempt to relocate built-in include paths that
start with the compiled-in sysroot location (e.g., the g++ include dir, in
this case). This isn't surprising really: normally you either prepend the
sysroot location or you don't (as specified by cppdefault.c); none of the
built-in paths normally *start* with the sysroot location and need to be
relocated. However, in this odd-ball case of trying to use the C++ headers
from the sysroot, one of the paths *does* need to be relocated in this way.
The following patch adds code to add_standard_paths to do the sysroot
translation (for oddball configurations like mine).
Tested before/after on a x86_64-unknown-linux-gnu system, with
--enable-languages=all, RUNTESTFLAGS='--target_board=unix\{-m32,-m64\}'.
No changes in test results. (!! usually there are some, only dates this time!)
Also built my special cross configuration, that worked as expected.
OK for trunk?
chris
---
[gcc/ChangeLog]
2011-06-25 Chris Demetriou <c...@google.com>
* cppdefault.h (cpp_TARGET_SYSTEM_ROOT): New variable.
(cpp_TARGET_SYSTEM_ROOT_len): Likewise.
* cppdefault.c (cpp_TARGET_SYSTEM_ROOT): Likewise.
(cpp_TARGET_SYSTEM_ROOT_len): Likewise.
* incpath.c (add_standard_paths): Relocate paths that start
with the compiled-in sysroot path, if a sysroot is given.
Index: incpath.c
===================================================================
--- incpath.c (revision 175395)
+++ incpath.c (working copy)
@@ -133,6 +133,30 @@ add_standard_paths (const char *sysroot, const cha
int relocated = cpp_relocated();
size_t len;
+ if (sysroot && (len = cpp_TARGET_SYSTEM_ROOT_len) != 0)
+ {
+ /* Look for directories that start with the compiled-in sysroot prefix.
+ "Translate" them, i.e. replace /usr/local/target/sys-root... with
+ SYSROOT and search them first. */
+ for (p = cpp_include_defaults; p->fname; p++)
+ {
+ if (!p->cplusplus || cxx_stdinc)
+ {
+ /* If we're going to add the sysroot to a path, then it
+ is not expected to start with the path to the sysroot. */
+ if (p->add_sysroot)
+ continue;
+ if (!filename_ncmp (p->fname, cpp_TARGET_SYSTEM_ROOT, len))
+ {
+ char *str = concat (sysroot, p->fname + len, NULL);
+ if (p->multilib && imultilib)
+ str = concat (str, dir_separator_str, imultilib, NULL);
+ add_path (str, SYSTEM, p->cxx_aware, false);
+ }
+ }
+ }
+ }
+
if (iprefix && (len = cpp_GCC_INCLUDE_DIR_len) != 0)
{
/* Look for directories that start with the standard prefix.
Index: cppdefault.c
===================================================================
--- cppdefault.c (revision 175395)
+++ cppdefault.c (working copy)
@@ -117,6 +117,15 @@ const char cpp_EXEC_PREFIX[] = STANDARD_EXEC_PREFI
/* This value is set by cpp_relocated at runtime */
const char *gcc_exec_prefix;
+/* The configured target system root (sysroot). */
+#ifdef TARGET_SYSTEM_ROOT
+const char cpp_TARGET_SYSTEM_ROOT[] = TARGET_SYSTEM_ROOT;
+const size_t cpp_TARGET_SYSTEM_ROOT_len = sizeof TARGET_SYSTEM_ROOT - 1;
+#else
+const char cpp_TARGET_SYSTEM_ROOT[] = "";
+const size_t cpp_TARGET_SYSTEM_ROOT_len = 0;
+#endif
+
/* Return true if the toolchain is relocated. */
bool
cpp_relocated (void)
Index: cppdefault.h
===================================================================
--- cppdefault.h (revision 175395)
+++ cppdefault.h (working copy)
@@ -63,6 +63,11 @@ extern const char cpp_EXEC_PREFIX[];
/* The run-time execution prefix. This is typically the lib/gcc
subdirectory of the actual installation. */
extern const char *gcc_exec_prefix;
+/* The configure-time target system root (sysroot) directory, or empty
+ string if none. */
+extern const char cpp_TARGET_SYSTEM_ROOT[];
+/* The length of the configure-time target system root directory. */
+extern const size_t cpp_TARGET_SYSTEM_ROOT_len;
/* Return true if the toolchain is relocated. */
bool cpp_relocated (void);
--
This patch is available for review at http://codereview.appspot.com/4641076
