Add directives to force stop unwinding.

On aarch64/x86/x86_64 add a macro that inserts a cfi directive that will
stop unwinding.

For arm, clang doesn't allow emitting .cantunwind, so add a comment and
leave it the same as it current is.

Add this macro to __libc_init and __start_thread.

Also, remove duplicate compilation of libc_init_static.cpp that already
includes the static library that includes that file.

Bug: 15469122

Test: Did unwinds using new unwinder tool (unwind) and debuggerd -b
Test: and verified new unwinder works on aarch64/x86/x86_64.
Test: Verified that it works on old unwinder for aarch64/x86, but
Test: x86_64 doesn't work properly, but as well as before.
Change-Id: I77302e8f6c7ba1549d98a4a164106ee82c9ecadc

libc/Android.bp

@@ -1826,7 +1826,6 @@ cc_library {
             "bionic/dl_iterate_phdr_static.cpp",
             "bionic/icu_static.cpp",
             "bionic/malloc_common.cpp",
-            "bionic/libc_init_static.cpp",
         ],
         cflags: ["-DLIBC_STATIC"],
         whole_static_libs: ["libc_init_static"],

libc/bionic/clone.cpp

@@ -34,11 +34,15 @@
 
 #include "pthread_internal.h"
 
+#include "private/bionic_macros.h"
+
 extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
 extern "C" __noreturn void __exit(int status);
 
 // Called from the __bionic_clone assembler to call the thread function then exit.
 extern "C" __LIBC_HIDDEN__ void __start_thread(int (*fn)(void*), void* arg) {
+  BIONIC_STOP_UNWIND;
+
   pthread_internal_t* self = __get_thread();
   if (self && self->tid == -1) {
     self->tid = syscall(__NR_gettid);

libc/bionic/libc_init_dynamic.cpp

@@ -52,6 +52,7 @@
 #include "libc_init_common.h"
 
 #include "private/bionic_globals.h"
+#include "private/bionic_macros.h"
 #include "private/bionic_ssp.h"
 #include "private/bionic_tls.h"
 #include "private/KernelArgumentBlock.h"
@@ -108,6 +109,7 @@ __noreturn void __libc_init(void* raw_args,
                             void (*onexit)(void) __unused,
                             int (*slingshot)(int, char**, char**),
                             structors_array_t const * const structors) {
+  BIONIC_STOP_UNWIND;
 
   KernelArgumentBlock args(raw_args);
 

libc/bionic/libc_init_static.cpp

@@ -40,6 +40,7 @@
 #include "pthread_internal.h"
 
 #include "private/bionic_globals.h"
+#include "private/bionic_macros.h"
 #include "private/bionic_page.h"
 #include "private/bionic_tls.h"
 #include "private/KernelArgumentBlock.h"
@@ -82,6 +83,8 @@ __noreturn void __libc_init(void* raw_args,
                             void (*onexit)(void) __unused,
                             int (*slingshot)(int, char**, char**),
                             structors_array_t const * const structors) {
+  BIONIC_STOP_UNWIND;
+
   KernelArgumentBlock args(raw_args);
   __libc_init_main_thread(args);
 

libc/private/bionic_macros.h

@@ -66,4 +66,17 @@ static inline T* align_up(T* p, size_t align) {
   return reinterpret_cast<T*>(align_up(reinterpret_cast<uintptr_t>(p), align));
 }
 
+#if defined(__arm__)
+// Do not emit anything for arm, clang does not allow emiting an arm unwind
+// directive.
+// #define BIONIC_STOP_UNWIND asm volatile(".cantunwind")
+#define BIONIC_STOP_UNWIND
+#elif defined(__aarch64__)
+#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined x30")
+#elif defined(__i386__)
+#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined \%eip")
+#elif defined(__x86_64__)
+#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined \%rip")
+#endif
+
 #endif // _BIONIC_MACROS_H_