From: Olivier Hainque <[email protected]>
Even though Android is a variant of Linux, it doesn't expose
a _r_debug struct so handily as with GLIBC. Program headers
from dl_iterate_phdr show name/addr sequences of pairs such as
dpli_name dpli_addr
/system/bin/linker64 0x720f3d3000
/data/data/com.arachnoid.sshelper/home/testone 0x64f217f000 (exe)
[vdso] 0x720f3d2000
/apex/com.android.runtime/lib64/bionic/libc.so 0x720de25000
/apex/com.android.runtime/lib64/bionic/libdl.so 0x720ddd6000
/system/lib64/libnetd_client.so 0x720dc83000
/system/lib64/libc++.so 0x720d30b000
/apex/com.android.runtime/lib64/bionic/libm.so 0x720dcc3000
The name is not empty for the executable and there's no documentation
saying it would always come second or so, so this provides no obvious
reliable means to discriminate the exe load address.
As a variant of linux, the default link policy for Android authorizes
undefined refs when creating shared libs, with resolution deferred at least
until the lib is loaded. "main" will have to be available then, so resort
to dladdr(&main) to figure out the main module load address from here.
gcc/ada/ChangeLog:
* adaint.c (__gnat_get_executable_load_address): Provide
an implementation based on dladdr(&main) and use it for Android.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/adaint.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff --git a/gcc/ada/adaint.c b/gcc/ada/adaint.c
index 9e349d6907c..552b40af07f 100644
--- a/gcc/ada/adaint.c
+++ b/gcc/ada/adaint.c
@@ -3481,10 +3481,52 @@ __gnat_cpu_set (int cpu, size_t count ATTRIBUTE_UNUSED,
cpu_set_t *set)
#include <link.h>
#endif
+/* Even though Android is a variant of Linux, it doesn't expose
+ a _r_debug struct so handily as GLIBC. Program headers from
+ dl_iterate_phdr show name/addr sequences of pairs such as
+
+ dpli_name dpli_addr
+ /system/bin/linker64 0x720f3d3000
+ /data/data/com.arachnoid.sshelper/home/testone 0x64f217f000 (exe)
+ [vdso] 0x720f3d2000
+ /apex/com.android.runtime/lib64/bionic/libc.so 0x720de25000
+ /apex/com.android.runtime/lib64/bionic/libdl.so 0x720ddd6000
+ /system/lib64/libnetd_client.so 0x720dc83000
+ /system/lib64/libc++.so 0x720d30b000
+ /apex/com.android.runtime/lib64/bionic/libm.so 0x720dcc3000
+
+ The name is not empty for the executable and there's no documentation
+ saying it would always come second or so, so this provides no obvious
+ reliable means to discriminate the exe load address.
+
+ As a variant of linux, the default link policy for Android authorizes
+ undefined refs when creating shared libs, with resolution deferred at least
+ until the lib is loaded. "main" will have to be available then, so resort
+ to dladdr(&main) to figure out the main module load address from here.
+
+ Achieve this through a local feature macro in case other platforms can use
+ such a facility. */
+
+#if defined (__ANDROID__)
+#define _USE_DLADDR_MAIN
+#endif
+
const void *
__gnat_get_executable_load_address (void)
{
-#if defined (__APPLE__)
+#if defined (_USE_DLADDR_MAIN)
+ /* We might be in a shared libgnat here, so a ref to "main"
+ cannot be assumed to work on all platforms. */
+
+ #define _GNU_SOURCE
+ #include <dlfcn.h>
+
+ extern int main();
+ Dl_info info;
+
+ dladdr((void *)&main, &info);
+ return info.dli_fbase;
+#elif defined (__APPLE__)
return _dyld_get_image_header (0);
#elif defined (__linux__) && (defined (__GLIBC__) || defined (__UCLIBC__))
--
2.53.0
