Add debug info for link-time generated thunks.

Add debug info for method call thunks (currently unused) and
Baker read barrier thunks. Refactor debug info generation
for trampolines and record their sizes; change their names
to start with upper-case letters, so that they can be easily
generated as `#fn_name`.

This improved debug info must be generated by `dex2oat -g`,
the debug info generated by `oatdump --symbolize` remains
the same as before, except for the renamed trampolines and
an adjustment for "code delta", i.e. the Thumb mode bit.

Cortex-A53 erratum 843419 workaround thunks are not covered
by this CL.

Test: Manual; run-test --gdb -Xcompiler-option -g 160, pull
      symbols for gdbclient, break in the introspection
      entrypoint, check that gdb knows the new symbols
      (and disassembles them) and `backtrace` works when
      setting $pc to an address in the thunk.
Bug: 36141117
Change-Id: Id224b72cfa7a0628799c7db65e66e24c8517aabf
diff --git a/compiler/debug/method_debug_info.h b/compiler/debug/method_debug_info.h
index ed1da2c..5678910 100644
--- a/compiler/debug/method_debug_info.h
+++ b/compiler/debug/method_debug_info.h
@@ -17,6 +17,8 @@
 #ifndef ART_COMPILER_DEBUG_METHOD_DEBUG_INFO_H_
 #define ART_COMPILER_DEBUG_METHOD_DEBUG_INFO_H_
 
+#include <string>
+
 #include "compiled_method.h"
 #include "dex_file.h"
 
@@ -24,7 +26,7 @@
 namespace debug {
 
 struct MethodDebugInfo {
-  const char* trampoline_name;
+  std::string trampoline_name;
   const DexFile* dex_file;  // Native methods (trampolines) do not reference dex file.
   size_t class_def_index;
   uint32_t dex_method_index;