1From 1fc21976be58987f036caa1103b821d51449af05 Mon Sep 17 00:00:00 2001
2From: David 'Digit' Turner <digit@google.com>
3Date: Fri, 17 Feb 2012 19:38:08 +0100
4Subject: gcc: prevent crash on Eclair and older platforms.
5
6The point of this patch is to work-around a bug in the Eclair
7dynamic linker, which doesn't support weak symbols. By default,
8libsupc++ and libstdc++ generate static C++ constructors that
9reference weak symbols.
10
11When they are statically linked into shared libraries, the
12corresponding code is referenced in its .init_array section
13and run when the shared library is loaded.
14
15On Eclair and previous release, the weak symbol is not resolved
16before the constructor are launched, resulting in a crash when
17the PLT entry tries to jump to address 0.
18
19By not generating weak symbol references, we avoid the problem
20completely. And we don't need them because the pthread symbols
21are all in the C library on Android, unlike legacy Linux systems
22which put them in libpthread.so (and provide weak stubs in libc.so).
23---
24 gcc-4.8/libgcc/gthr-posix.h | 13 +++++++++++++
25 gcc-4.9/libgcc/gthr-posix.h | 13 +++++++++++++
26 3 files changed, 39 insertions(+)
27
28diff --git a/gcc-4.8/libgcc/gthr-posix.h b/gcc-4.8/libgcc/gthr-posix.h
29index f0d8cd7..1d03af0 100644
30--- a/gcc-4.8/libgcc/gthr-posix.h
31+++ b/gcc-4.8/libgcc/gthr-posix.h
32@@ -32,6 +32,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
33 #define __GTHREADS 1
34 #define __GTHREADS_CXX0X 1
35
36+/* The following should normally be in a different header file,
37+ * but I couldn't find the right location. The point of the macro
38+ * definition below is to prevent libsupc++ and libstdc++ to reference
39+ * weak symbols in their static C++ constructors. Such code crashes
40+ * when a shared object linked statically to these libraries is
41+ * loaded on Android 2.1 (Eclair) and older platform releases, due
42+ * to a dynamic linker bug.
43+ */
44+#ifdef __ANDROID__
45+#undef GTHREAD_USE_WEAK
46+#define GTHREAD_USE_WEAK 0
47+#endif
48+
49 #include <pthread.h>
50
51 #if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
52diff --git a/gcc-4.9/libgcc/gthr-posix.h b/gcc-4.9/libgcc/gthr-posix.h
53index 7003a91..19d7d5f 100644
54--- a/gcc-4.9/libgcc/gthr-posix.h
55+++ b/gcc-4.9/libgcc/gthr-posix.h
56@@ -32,6 +32,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
57 #define __GTHREADS 1
58 #define __GTHREADS_CXX0X 1
59
60+/* The following should normally be in a different header file,
61+ * but I couldn't find the right location. The point of the macro
62+ * definition below is to prevent libsupc++ and libstdc++ to reference
63+ * weak symbols in their static C++ constructors. Such code crashes
64+ * when a shared object linked statically to these libraries is
65+ * loaded on Android 2.1 (Eclair) and older platform releases, due
66+ * to a dynamic linker bug.
67+ */
68+#ifdef __ANDROID__
69+#undef GTHREAD_USE_WEAK
70+#define GTHREAD_USE_WEAK 0
71+#endif
72+
73 #include <pthread.h>
74
75 #if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
76--
771.9.1.423.g4596e3a
78
79