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-4.6/gcc/gthr-posix.h    | 13 +++++++++++++
25 gcc-4.8/libgcc/gthr-posix.h | 13 +++++++++++++
26 gcc-4.9/libgcc/gthr-posix.h | 13 +++++++++++++
27 3 files changed, 39 insertions(+)
28
29diff --git a/gcc-4.6/gcc/gthr-posix.h b/gcc-4.6/gcc/gthr-posix.h
30index ecb06e2..8372c64 100644
31--- a/gcc-4.6/gcc/gthr-posix.h
32+++ b/gcc-4.6/gcc/gthr-posix.h
33@@ -38,6 +38,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
34 #define _REENTRANT 1
35 #endif
36
37+/* The following should normally be in a different header file,
38+ * but I couldn't find the right location. The point of the macro
39+ * definition below is to prevent libsupc++ and libstdc++ to reference
40+ * weak symbols in their static C++ constructors. Such code crashes
41+ * when a shared object linked statically to these libraries is
42+ * loaded on Android 2.1 (Eclair) and older platform releases, due
43+ * to a dynamic linker bug.
44+ */
45+#ifdef __ANDROID__
46+#undef GTHREAD_USE_WEAK
47+#define GTHREAD_USE_WEAK 0
48+#endif
49+
50 #include <pthread.h>
51 #include <unistd.h>
52
53diff --git a/gcc-4.8/libgcc/gthr-posix.h b/gcc-4.8/libgcc/gthr-posix.h
54index f0d8cd7..1d03af0 100644
55--- a/gcc-4.8/libgcc/gthr-posix.h
56+++ b/gcc-4.8/libgcc/gthr-posix.h
57@@ -32,6 +32,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
58 #define __GTHREADS 1
59 #define __GTHREADS_CXX0X 1
60
61+/* The following should normally be in a different header file,
62+ * but I couldn't find the right location. The point of the macro
63+ * definition below is to prevent libsupc++ and libstdc++ to reference
64+ * weak symbols in their static C++ constructors. Such code crashes
65+ * when a shared object linked statically to these libraries is
66+ * loaded on Android 2.1 (Eclair) and older platform releases, due
67+ * to a dynamic linker bug.
68+ */
69+#ifdef __ANDROID__
70+#undef GTHREAD_USE_WEAK
71+#define GTHREAD_USE_WEAK 0
72+#endif
73+
74 #include <pthread.h>
75
76 #if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
77diff --git a/gcc-4.9/libgcc/gthr-posix.h b/gcc-4.9/libgcc/gthr-posix.h
78index 7003a91..19d7d5f 100644
79--- a/gcc-4.9/libgcc/gthr-posix.h
80+++ b/gcc-4.9/libgcc/gthr-posix.h
81@@ -32,6 +32,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
82 #define __GTHREADS 1
83 #define __GTHREADS_CXX0X 1
84
85+/* The following should normally be in a different header file,
86+ * but I couldn't find the right location. The point of the macro
87+ * definition below is to prevent libsupc++ and libstdc++ to reference
88+ * weak symbols in their static C++ constructors. Such code crashes
89+ * when a shared object linked statically to these libraries is
90+ * loaded on Android 2.1 (Eclair) and older platform releases, due
91+ * to a dynamic linker bug.
92+ */
93+#ifdef __ANDROID__
94+#undef GTHREAD_USE_WEAK
95+#define GTHREAD_USE_WEAK 0
96+#endif
97+
98 #include <pthread.h>
99
100 #if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
101--
1021.9.1.423.g4596e3a
103
104