Fix ABI breakage in libc.so and libm.so between 1.6 and Eclair.
For a detailed description of the problem and why this fix is
needed, plrease read the comments in libgcc_compat.c
diff --git a/libc/Android.mk b/libc/Android.mk
index 12d5c92..5718d18 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -288,6 +288,7 @@
arch-arm/bionic/clone.S \
arch-arm/bionic/ffs.S \
arch-arm/bionic/kill.S \
+ arch-arm/bionic/libgcc_compat.c \
arch-arm/bionic/tkill.S \
arch-arm/bionic/memcmp.S \
arch-arm/bionic/memcmp16.S \
diff --git a/libc/arch-arm/bionic/libgcc_compat.c b/libc/arch-arm/bionic/libgcc_compat.c
new file mode 100644
index 0000000..886d025
--- /dev/null
+++ b/libc/arch-arm/bionic/libgcc_compat.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* This file contains dummy references to libgcc.a functions to force the
+ * dynamic linker to copy their definition into the final libc.so binary.
+ *
+ * They are required to ensure backwards binary compatibility with
+ * Android 1.5 and Android 1.6 system images. Some applications built
+ * using the NDK require them to be here.
+ *
+ * Now, for a more elaborate description of the issue:
+ *
+ * libgcc.a is a compiler-specific library containing various helper
+ * functions used to implement certain operations that are not necessarily
+ * supported by the target CPU. For example, integer division doesn't have a
+ * corresponding CPU instruction on ARMv5, and is instead implemented in the
+ * compiler-generated machine code as a call to an __idiv helper function.
+ *
+ * Normally, one has to place libgcc.a in the link command used to generate
+ * target binaries (shared libraries and executables) after all objects and
+ * static libraries, but before dependent shared libraries, i.e. something
+ * like:
+ * gcc <options> -o libfoo.so foo.a libgcc.a -lc -lm
+ *
+ * This ensures that any helper function needed by the code in foo.a is copied
+ * into the final libfoo.so. Unfortunately, the Android build system has been
+ * using this instead:
+ *
+ * gcc <options> -o libfoo.so foo.a -lc -lm libgcc.a
+ *
+ * The problem with this is that if one helper function needed by foo.a has
+ * already been copied into libc.so or libm.so, then nothing will be copied
+ * into libfoo.so. Instead, a symbol import definition will be added to it
+ * so libfoo.so can directly call the one in libc.so at runtime.
+ *
+ * When changing toolchains for 2.0, the set of helper functions copied to
+ * libc.so changed, which resulted in some native shared libraries generated
+ * with the NDK to fail to load properly.
+ *
+ * The NDK has been fixed after 1.6_r1 to use the correct link command, so
+ * any native shared library generated with it should now be safe from that
+ * problem. On the other hand, existing shared libraries distributed with
+ * applications that were generated with a previous version of the NDK
+ * still need all 1.5/1.6 helper functions in libc.so and libn.so
+ *
+ * Final note: some of the functions below should really be in libm.so to
+ * completely reflect the state of 1.5/1.6 system images. However,
+ * since libm.so depends on libc.so, it's easier to put all of
+ * these in libc.so instead, since the dynamic linker will always
+ * search in libc.so before libm.so for dependencies.
+ */
+
+#define COMPAT_FUNCTIONS_LIST \
+ XX(__adddf3) \
+ XX(__addsf3) \
+ XX(__aeabi_cdcmpeq) \
+ XX(__aeabi_cdcmple) \
+ XX(__aeabi_cdrcmple) \
+ XX(__aeabi_d2f) \
+ XX(__aeabi_d2iz) \
+ XX(__aeabi_dadd) \
+ XX(__aeabi_dcmpeq) \
+ XX(__aeabi_dcmpge) \
+ XX(__aeabi_dcmpgt) \
+ XX(__aeabi_dcmple) \
+ XX(__aeabi_dcmplt) \
+ XX(__aeabi_dcmpun) \
+ XX(__aeabi_ddiv) \
+ XX(__aeabi_dmul) \
+ XX(__aeabi_drsub) \
+ XX(__aeabi_dsub) \
+ XX(__aeabi_f2d) \
+ XX(__aeabi_f2iz) \
+ XX(__aeabi_fadd) \
+ XX(__aeabi_fcmpun) \
+ XX(__aeabi_fdiv) \
+ XX(__aeabi_fmul) \
+ XX(__aeabi_frsub) \
+ XX(__aeabi_fsub) \
+ XX(__aeabi_i2d) \
+ XX(__aeabi_i2f) \
+ XX(__aeabi_l2d) \
+ XX(__aeabi_l2f) \
+ XX(__aeabi_lmul) \
+ XX(__aeabi_ui2d) \
+ XX(__aeabi_ui2f) \
+ XX(__aeabi_ul2d) \
+ XX(__aeabi_ul2f) \
+ XX(__cmpdf2) \
+ XX(__divdf3) \
+ XX(__divsf3) \
+ XX(__eqdf2) \
+ XX(__extendsfdf2) \
+ XX(__fixdfsi) \
+ XX(__fixsfsi) \
+ XX(__floatdidf) \
+ XX(__floatdisf) \
+ XX(__floatsidf) \
+ XX(__floatsisf) \
+ XX(__floatundidf) \
+ XX(__floatundisf) \
+ XX(__floatunsidf) \
+ XX(__floatunsisf) \
+ XX(__gedf2) \
+ XX(__gtdf2) \
+ XX(__ledf2) \
+ XX(__ltdf2) \
+ XX(__muldf3) \
+ XX(__muldi3) \
+ XX(__mulsf3) \
+ XX(__nedf2) \
+ XX(__subdf3) \
+ XX(__subsf3) \
+ XX(__truncdfsf2) \
+ XX(__unorddf2) \
+ XX(__unordsf2) \
+
+#define XX(f) extern void f(void);
+COMPAT_FUNCTIONS_LIST
+#undef XX
+
+void __bionic_libgcc_compat_hooks(void)
+{
+#define XX(f) f();
+COMPAT_FUNCTIONS_LIST
+#undef XX
+}