libunwind: limit stack usage in unwind cursor

Obtained from FreeBSD SVN r302475

Differential Revision:	https://reviews.llvm.org/D22570

llvm-svn: 276128

libunwind/include/__libunwind_config.h

@@ -22,18 +22,22 @@
 #  define _LIBUNWIND_TARGET_I386 1
 #  define _LIBUNWIND_CONTEXT_SIZE 8
 #  define _LIBUNWIND_CURSOR_SIZE 19
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 9
 # elif defined(__x86_64__)
 #  define _LIBUNWIND_TARGET_X86_64 1
 #  define _LIBUNWIND_CONTEXT_SIZE 21
 #  define _LIBUNWIND_CURSOR_SIZE 33
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 17
 # elif defined(__ppc__)
 #  define _LIBUNWIND_TARGET_PPC 1
 #  define _LIBUNWIND_CONTEXT_SIZE 117
 #  define _LIBUNWIND_CURSOR_SIZE 128
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 113
 # elif defined(__aarch64__)
 #  define _LIBUNWIND_TARGET_AARCH64 1
 #  define _LIBUNWIND_CONTEXT_SIZE 66
 #  define _LIBUNWIND_CURSOR_SIZE 78
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 96
 # elif defined(__arm__)
 #  define _LIBUNWIND_TARGET_ARM 1
 #  if defined(__ARM_WMMX)
@@ -43,10 +47,12 @@
 #    define _LIBUNWIND_CONTEXT_SIZE 42
 #    define _LIBUNWIND_CURSOR_SIZE 49
 #  endif
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 96
 # elif defined(__or1k__)
 #  define _LIBUNWIND_TARGET_OR1K 1
 #  define _LIBUNWIND_CONTEXT_SIZE 16
 #  define _LIBUNWIND_CURSOR_SIZE 28
+#  define _LIBUNWIND_HIGHEST_DWARF_REGISTER 32
 # else
 #  error "Unsupported architecture."
 # endif
@@ -59,6 +65,7 @@
 # define _LIBUNWIND_TARGET_OR1K 1
 # define _LIBUNWIND_CONTEXT_SIZE 128
 # define _LIBUNWIND_CURSOR_SIZE 140
+# define _LIBUNWIND_HIGHEST_DWARF_REGISTER 120
 #endif // _LIBUNWIND_IS_NATIVE_ONLY
 
 #endif // ____LIBUNWIND_CONFIG_H__

libunwind/src/DwarfParser.hpp

@@ -62,7 +62,7 @@ public:
   };
 
   enum {
-    kMaxRegisterNumber = 120
+    kMaxRegisterNumber = _LIBUNWIND_HIGHEST_DWARF_REGISTER
   };
   enum RegisterSavedWhere {
     kRegisterUnused,