[GWP-ASan] [Scudo] Add GWP-ASan backtrace for alloc/free to Scudo.

[hctim]

Summary

Adds allocation and deallocation stack trace support to Scudo. The
default provided backtrace library for GWP-ASan is supplied by the libc
unwinder, and is suitable for production variants of Scudo. If Scudo in future
has its own unwinder, it may choose to use its own over the generic unwinder
instead.

[hctim]

• Readded newline from merge conflict cleanup.

compiler-rt/lib/scudo/CMakeLists.txt

 add_compiler_rt_component(scudo)
 
 include_directories(..)
 
 set(SCUDO_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 # SANITIZER_COMMON_CFLAGS include -fno-builtin, but we actually want builtins!
 list(APPEND SCUDO_CFLAGS -fbuiltin)
 append_rtti_flag(OFF SCUDO_CFLAGS)
 
 set(SCUDO_MINIMAL_DYNAMIC_LIBS ${SANITIZER_COMMON_LINK_LIBS})
 append_list_if(COMPILER_RT_HAS_LIBDL dl SCUDO_MINIMAL_DYNAMIC_LIBS)
 append_list_if(COMPILER_RT_HAS_LIBRT rt SCUDO_MINIMAL_DYNAMIC_LIBS)
 append_list_if(COMPILER_RT_HAS_LIBPTHREAD pthread SCUDO_MINIMAL_DYNAMIC_LIBS)
 append_list_if(COMPILER_RT_HAS_LIBLOG log SCUDO_MINIMAL_DYNAMIC_LIBS)
+append_list_if(COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG -fno-omit-frame-pointer
+               SCUDO_CFLAGS)
+append_list_if(COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG
+               -mno-omit-leaf-frame-pointer SCUDO_CFLAGS)
 
 set(SCUDO_DYNAMIC_LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS})
 # Use gc-sections by default to avoid unused code being pulled in.
 list(APPEND SCUDO_DYNAMIC_LINK_FLAGS -Wl,--gc-sections)
 
 if(ANDROID)
 # Put most Sanitizer shared libraries in the global group. For more details, see
 # android-changes-for-ndk-developers.md#changes-to-library-search-order
   if (COMPILER_RT_HAS_Z_GLOBAL)
     list(APPEND SCUDO_DYNAMIC_LINK_FLAGS -Wl,-z,global)
   endif()
 endif()
 
 # The minimal Scudo runtime does not inlude the UBSan runtime.
 set(SCUDO_MINIMAL_OBJECT_LIBS
   RTSanitizerCommonNoTermination
   RTSanitizerCommonLibc
   RTInterception)
 
 if (COMPILER_RT_HAS_GWP_ASAN)
   # Currently, Scudo uses the GwpAsan flag parser. This backs onto the flag
   # parsing mechanism of sanitizer_common. Once Scudo has its own flag parsing,
   # and parses GwpAsan options, you can remove this dependency.
-  list(APPEND SCUDO_MINIMAL_OBJECT_LIBS RTGwpAsan RTGwpAsanOptionsParser)
+  list(APPEND SCUDO_MINIMAL_OBJECT_LIBS RTGwpAsan RTGwpAsanOptionsParser
+                                        RTGwpAsanBacktraceLibc)
   list(APPEND SCUDO_CFLAGS -DGWP_ASAN_HOOKS)
 endif()
 
 set(SCUDO_OBJECT_LIBS ${SCUDO_MINIMAL_OBJECT_LIBS})
 set(SCUDO_DYNAMIC_LIBS ${SCUDO_MINIMAL_DYNAMIC_LIBS})
 
 if (FUCHSIA)
   list(APPEND SCUDO_CFLAGS -nostdinc++)

compiler-rt/lib/scudo/scudo_allocator.cpp

 #include "scudo_utils.h"
 
 #include "sanitizer_common/sanitizer_allocator_checks.h"
 #include "sanitizer_common/sanitizer_allocator_interface.h"
 #include "sanitizer_common/sanitizer_quarantine.h"
 
 #ifdef GWP_ASAN_HOOKS
 # include "gwp_asan/guarded_pool_allocator.h"
+# include "gwp_asan/optional/backtrace.h"
 # include "gwp_asan/optional/options_parser.h"
 #endif // GWP_ASAN_HOOKS
 
 #include <errno.h>
 #include <string.h>
 
 namespace __scudo {
 

 static BackendT &getBackend() {
   return Instance.Backend;
 }
 
 void initScudo() {
   Instance.init();
 #ifdef GWP_ASAN_HOOKS
   gwp_asan::options::initOptions();
-  GuardedAlloc.init(gwp_asan::options::getOptions());
+  gwp_asan::options::Options &Opts = gwp_asan::options::getOptions();
+  Opts.Backtrace = gwp_asan::options::getBacktraceFunction();
+  Opts.PrintBacktrace = gwp_asan::options::getPrintBacktraceFunction();
+  GuardedAlloc.init(Opts);
 #endif // GWP_ASAN_HOOKS
 }
 
 void ScudoTSD::init() {
   getBackend().initCache(&Cache);
   memset(QuarantineCachePlaceHolder, 0, sizeof(QuarantineCachePlaceHolder));
 }