hphp/runtime/vm/jit/unwind-x64.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2014 Facebook, Inc. (http://www.facebook.com)     |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_VM_TRANSLATOR_UNWIND_X64_H_
  18 #define incl_HPHP_VM_TRANSLATOR_UNWIND_X64_H_
  19
  20 #include <cstdlib>
  21 #include <sstream>
  22 #include <string>
  23 #include <unwind.h>
  24 #include <memory>
  25 #include <exception>
  26 #include <typeinfo>
  27
  28 #include "hphp/runtime/base/rds.h"
  29 #include "hphp/runtime/base/typed-value.h"
  30 #include "hphp/runtime/base/types.h"
  31 #include "hphp/runtime/vm/jit/types.h"
  32 #include "hphp/runtime/vm/tread-hash-map.h"
  33 #include "hphp/util/asm-x64.h"
  34 #include "hphp/util/assertions.h"
  35
  36 namespace HPHP { namespace JIT {
  37
  38 //////////////////////////////////////////////////////////////////////
  39
  40 typedef TreadHashMap<CTCA, TCA, ctca_identity_hash> CatchTraceMap;
  41
  42 /*
  43  * Information the unwinder needs stored in RDS, and the RDS::Link for
  44  * it.  Used to pass values between unwinder code and catch traces.
  45  */
  46 struct UnwindRDS {
  47   int64_t unwinderScratch;
  48   TypedValue unwinderTv;
  49   bool doSideExit;
  50 };
  51 extern RDS::Link<UnwindRDS> unwindRdsInfo;
  52
  53 inline ptrdiff_t unwinderScratchOff() {
  54   return unwindRdsInfo.handle() + offsetof(UnwindRDS, unwinderScratch);
  55 }
  56
  57 inline ptrdiff_t unwinderSideExitOff() {
  58   return unwindRdsInfo.handle() + offsetof(UnwindRDS, doSideExit);
  59 }
  60
  61 inline ptrdiff_t unwinderTvOff() {
  62   return unwindRdsInfo.handle() + offsetof(UnwindRDS, unwinderTv);
  63 }
  64
  65 //////////////////////////////////////////////////////////////////////
  66
  67 /*
  68  * Meant to work like __cxxabiv1::__is_dependent_exception
  69  * See libstdc++-v3/libsupc++/unwind-cxx.h in GCC
  70  */
  71 static inline bool isDependentException(uint64_t c)
  72 {
  73   return (c & 1);
  74 }
  75
  76 /**
  77  * Meant to work like __cxxabiv1::__get_object_from_ue() but with a specific
  78  * return type.
  79  * See libstdc++-v3/libsupc++/unwind-cxx.h in GCC
  80  */
  81 inline std::exception* exceptionFromUnwindException(
  82   _Unwind_Exception* exceptionObj)
  83 {
  84   constexpr size_t sizeOfDependentException = 112;
  85   if (isDependentException(exceptionObj->exception_class)) {
  86     return *reinterpret_cast<std::exception**>(
  87       reinterpret_cast<char*>(exceptionObj + 1) - sizeOfDependentException);
  88   } else {
  89     return reinterpret_cast<std::exception*>(exceptionObj + 1);
  90   }
  91 }
  92
  93 inline const std::type_info& typeInfoFromUnwindException(
  94   _Unwind_Exception* exceptionObj
  95   )
  96 {
  97   if (isDependentException(exceptionObj->exception_class)) {
  98     // like __cxxabiv1::__get_refcounted_exception_header_from_obj()
  99     constexpr size_t sizeOfRefcountedException = 128;
 100     char * obj = reinterpret_cast<char*>(
 101         exceptionFromUnwindException(exceptionObj));
 102     char * header = obj - sizeOfRefcountedException;
 103     // Dereference the exc field, the type_info* is the first field inside that
 104     constexpr size_t excOffset = 16;
 105     return *reinterpret_cast<std::type_info*>(header + excOffset);
 106   } else {
 107     // like __cxxabiv1::__get_exception_header_from_ue()
 108     constexpr size_t sizeOfCxaException = 112;
 109     return **reinterpret_cast<std::type_info**>(
 110       reinterpret_cast<char*>(exceptionObj + 1) - sizeOfCxaException);
 111   }
 112 }
 113
 114 /*
 115  * Called whenever we create a new translation cache for the whole
 116  * region of code.
 117  */
 118 typedef std::shared_ptr<void> UnwindInfoHandle;
 119 UnwindInfoHandle register_unwind_region(unsigned char* address, size_t size);
 120
 121 //////////////////////////////////////////////////////////////////////
 122
 123 }}
 124
 125 #endif