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      1 //===-- ExceptionDemo.cpp - An example using llvm Exceptions --------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Demo program which implements an example LLVM exception implementation, and
     11 // shows several test cases including the handling of foreign exceptions.
     12 // It is run with type info types arguments to throw. A test will
     13 // be run for each given type info type. While type info types with the value
     14 // of -1 will trigger a foreign C++ exception to be thrown; type info types
     15 // <= 6 and >= 1 will cause the associated generated exceptions to be thrown
     16 // and caught by generated test functions; and type info types > 6
     17 // will result in exceptions which pass through to the test harness. All other
     18 // type info types are not supported and could cause a crash. In all cases,
     19 // the "finally" blocks of every generated test functions will executed
     20 // regardless of whether or not that test function ignores or catches the
     21 // thrown exception.
     22 //
     23 // examples:
     24 //
     25 // ExceptionDemo
     26 //
     27 //     causes a usage to be printed to stderr
     28 //
     29 // ExceptionDemo 2 3 7 -1
     30 //
     31 //     results in the following cases:
     32 //         - Value 2 causes an exception with a type info type of 2 to be
     33 //           thrown and caught by an inner generated test function.
     34 //         - Value 3 causes an exception with a type info type of 3 to be
     35 //           thrown and caught by an outer generated test function.
     36 //         - Value 7 causes an exception with a type info type of 7 to be
     37 //           thrown and NOT be caught by any generated function.
     38 //         - Value -1 causes a foreign C++ exception to be thrown and not be
     39 //           caught by any generated function
     40 //
     41 //     Cases -1 and 7 are caught by a C++ test harness where the validity of
     42 //         of a C++ catch(...) clause catching a generated exception with a
     43 //         type info type of 7 is explained by: example in rules 1.6.4 in
     44 //         http://mentorembedded.github.com/cxx-abi/abi-eh.html (v1.22)
     45 //
     46 // This code uses code from the llvm compiler-rt project and the llvm
     47 // Kaleidoscope project.
     48 //
     49 //===----------------------------------------------------------------------===//
     50 
     51 #include "llvm/ADT/STLExtras.h"
     52 #include "llvm/IR/Verifier.h"
     53 #include "llvm/ExecutionEngine/MCJIT.h"
     54 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
     55 #include "llvm/IR/DataLayout.h"
     56 #include "llvm/IR/DerivedTypes.h"
     57 #include "llvm/IR/IRBuilder.h"
     58 #include "llvm/IR/Intrinsics.h"
     59 #include "llvm/IR/LLVMContext.h"
     60 #include "llvm/IR/LegacyPassManager.h"
     61 #include "llvm/IR/Module.h"
     62 #include "llvm/Support/Dwarf.h"
     63 #include "llvm/Support/TargetSelect.h"
     64 #include "llvm/Target/TargetOptions.h"
     65 #include "llvm/Transforms/Scalar.h"
     66 
     67 // FIXME: Although all systems tested with (Linux, OS X), do not need this
     68 //        header file included. A user on ubuntu reported, undefined symbols
     69 //        for stderr, and fprintf, and the addition of this include fixed the
     70 //        issue for them. Given that LLVM's best practices include the goal
     71 //        of reducing the number of redundant header files included, the
     72 //        correct solution would be to find out why these symbols are not
     73 //        defined for the system in question, and fix the issue by finding out
     74 //        which LLVM header file, if any, would include these symbols.
     75 #include <cstdio>
     76 
     77 #include <sstream>
     78 #include <stdexcept>
     79 
     80 #include <inttypes.h>
     81 
     82 #ifndef USE_GLOBAL_STR_CONSTS
     83 #define USE_GLOBAL_STR_CONSTS true
     84 #endif
     85 
     86 // System C++ ABI unwind types from:
     87 //     http://mentorembedded.github.com/cxx-abi/abi-eh.html (v1.22)
     88 
     89 extern "C" {
     90 
     91   typedef enum {
     92     _URC_NO_REASON = 0,
     93     _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
     94     _URC_FATAL_PHASE2_ERROR = 2,
     95     _URC_FATAL_PHASE1_ERROR = 3,
     96     _URC_NORMAL_STOP = 4,
     97     _URC_END_OF_STACK = 5,
     98     _URC_HANDLER_FOUND = 6,
     99     _URC_INSTALL_CONTEXT = 7,
    100     _URC_CONTINUE_UNWIND = 8
    101   } _Unwind_Reason_Code;
    102 
    103   typedef enum {
    104     _UA_SEARCH_PHASE = 1,
    105     _UA_CLEANUP_PHASE = 2,
    106     _UA_HANDLER_FRAME = 4,
    107     _UA_FORCE_UNWIND = 8,
    108     _UA_END_OF_STACK = 16
    109   } _Unwind_Action;
    110 
    111   struct _Unwind_Exception;
    112 
    113   typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
    114                                                 struct _Unwind_Exception *);
    115 
    116   struct _Unwind_Exception {
    117     uint64_t exception_class;
    118     _Unwind_Exception_Cleanup_Fn exception_cleanup;
    119 
    120     uintptr_t private_1;
    121     uintptr_t private_2;
    122 
    123     // @@@ The IA-64 ABI says that this structure must be double-word aligned.
    124     //  Taking that literally does not make much sense generically.  Instead
    125     //  we provide the maximum alignment required by any type for the machine.
    126   } __attribute__((__aligned__));
    127 
    128   struct _Unwind_Context;
    129   typedef struct _Unwind_Context *_Unwind_Context_t;
    130 
    131   extern const uint8_t *_Unwind_GetLanguageSpecificData (_Unwind_Context_t c);
    132   extern uintptr_t _Unwind_GetGR (_Unwind_Context_t c, int i);
    133   extern void _Unwind_SetGR (_Unwind_Context_t c, int i, uintptr_t n);
    134   extern void _Unwind_SetIP (_Unwind_Context_t, uintptr_t new_value);
    135   extern uintptr_t _Unwind_GetIP (_Unwind_Context_t context);
    136   extern uintptr_t _Unwind_GetRegionStart (_Unwind_Context_t context);
    137 
    138 } // extern "C"
    139 
    140 //
    141 // Example types
    142 //
    143 
    144 /// This is our simplistic type info
    145 struct OurExceptionType_t {
    146   /// type info type
    147   int type;
    148 };
    149 
    150 
    151 /// This is our Exception class which relies on a negative offset to calculate
    152 /// pointers to its instances from pointers to its unwindException member.
    153 ///
    154 /// Note: The above unwind.h defines struct _Unwind_Exception to be aligned
    155 ///       on a double word boundary. This is necessary to match the standard:
    156 ///       http://mentorembedded.github.com/cxx-abi/abi-eh.html
    157 struct OurBaseException_t {
    158   struct OurExceptionType_t type;
    159 
    160   // Note: This is properly aligned in unwind.h
    161   struct _Unwind_Exception unwindException;
    162 };
    163 
    164 
    165 // Note: Not needed since we are C++
    166 typedef struct OurBaseException_t OurException;
    167 typedef struct _Unwind_Exception OurUnwindException;
    168 
    169 //
    170 // Various globals used to support typeinfo and generatted exceptions in
    171 // general
    172 //
    173 
    174 static std::map<std::string, llvm::Value*> namedValues;
    175 
    176 int64_t ourBaseFromUnwindOffset;
    177 
    178 const unsigned char ourBaseExcpClassChars[] =
    179 {'o', 'b', 'j', '\0', 'b', 'a', 's', '\0'};
    180 
    181 
    182 static uint64_t ourBaseExceptionClass = 0;
    183 
    184 static std::vector<std::string> ourTypeInfoNames;
    185 static std::map<int, std::string> ourTypeInfoNamesIndex;
    186 
    187 static llvm::StructType *ourTypeInfoType;
    188 static llvm::StructType *ourCaughtResultType;
    189 static llvm::StructType *ourExceptionType;
    190 static llvm::StructType *ourUnwindExceptionType;
    191 
    192 static llvm::ConstantInt *ourExceptionNotThrownState;
    193 static llvm::ConstantInt *ourExceptionThrownState;
    194 static llvm::ConstantInt *ourExceptionCaughtState;
    195 
    196 typedef std::vector<std::string> ArgNames;
    197 typedef std::vector<llvm::Type*> ArgTypes;
    198 
    199 //
    200 // Code Generation Utilities
    201 //
    202 
    203 /// Utility used to create a function, both declarations and definitions
    204 /// @param module for module instance
    205 /// @param retType function return type
    206 /// @param theArgTypes function's ordered argument types
    207 /// @param theArgNames function's ordered arguments needed if use of this
    208 ///        function corresponds to a function definition. Use empty
    209 ///        aggregate for function declarations.
    210 /// @param functName function name
    211 /// @param linkage function linkage
    212 /// @param declarationOnly for function declarations
    213 /// @param isVarArg function uses vararg arguments
    214 /// @returns function instance
    215 llvm::Function *createFunction(llvm::Module &module,
    216                                llvm::Type *retType,
    217                                const ArgTypes &theArgTypes,
    218                                const ArgNames &theArgNames,
    219                                const std::string &functName,
    220                                llvm::GlobalValue::LinkageTypes linkage,
    221                                bool declarationOnly,
    222                                bool isVarArg) {
    223   llvm::FunctionType *functType =
    224     llvm::FunctionType::get(retType, theArgTypes, isVarArg);
    225   llvm::Function *ret =
    226     llvm::Function::Create(functType, linkage, functName, &module);
    227   if (!ret || declarationOnly)
    228     return(ret);
    229 
    230   namedValues.clear();
    231   unsigned i = 0;
    232   for (llvm::Function::arg_iterator argIndex = ret->arg_begin();
    233        i != theArgNames.size();
    234        ++argIndex, ++i) {
    235 
    236     argIndex->setName(theArgNames[i]);
    237     namedValues[theArgNames[i]] = argIndex;
    238   }
    239 
    240   return(ret);
    241 }
    242 
    243 
    244 /// Create an alloca instruction in the entry block of
    245 /// the parent function.  This is used for mutable variables etc.
    246 /// @param function parent instance
    247 /// @param varName stack variable name
    248 /// @param type stack variable type
    249 /// @param initWith optional constant initialization value
    250 /// @returns AllocaInst instance
    251 static llvm::AllocaInst *createEntryBlockAlloca(llvm::Function &function,
    252                                                 const std::string &varName,
    253                                                 llvm::Type *type,
    254                                                 llvm::Constant *initWith = 0) {
    255   llvm::BasicBlock &block = function.getEntryBlock();
    256   llvm::IRBuilder<> tmp(&block, block.begin());
    257   llvm::AllocaInst *ret = tmp.CreateAlloca(type, 0, varName.c_str());
    258 
    259   if (initWith)
    260     tmp.CreateStore(initWith, ret);
    261 
    262   return(ret);
    263 }
    264 
    265 
    266 //
    267 // Code Generation Utilities End
    268 //
    269 
    270 //
    271 // Runtime C Library functions
    272 //
    273 
    274 // Note: using an extern "C" block so that static functions can be used
    275 extern "C" {
    276 
    277 // Note: Better ways to decide on bit width
    278 //
    279 /// Prints a 32 bit number, according to the format, to stderr.
    280 /// @param intToPrint integer to print
    281 /// @param format printf like format to use when printing
    282 void print32Int(int intToPrint, const char *format) {
    283   if (format) {
    284     // Note: No NULL check
    285     fprintf(stderr, format, intToPrint);
    286   }
    287   else {
    288     // Note: No NULL check
    289     fprintf(stderr, "::print32Int(...):NULL arg.\n");
    290   }
    291 }
    292 
    293 
    294 // Note: Better ways to decide on bit width
    295 //
    296 /// Prints a 64 bit number, according to the format, to stderr.
    297 /// @param intToPrint integer to print
    298 /// @param format printf like format to use when printing
    299 void print64Int(long int intToPrint, const char *format) {
    300   if (format) {
    301     // Note: No NULL check
    302     fprintf(stderr, format, intToPrint);
    303   }
    304   else {
    305     // Note: No NULL check
    306     fprintf(stderr, "::print64Int(...):NULL arg.\n");
    307   }
    308 }
    309 
    310 
    311 /// Prints a C string to stderr
    312 /// @param toPrint string to print
    313 void printStr(char *toPrint) {
    314   if (toPrint) {
    315     fprintf(stderr, "%s", toPrint);
    316   }
    317   else {
    318     fprintf(stderr, "::printStr(...):NULL arg.\n");
    319   }
    320 }
    321 
    322 
    323 /// Deletes the true previously allocated exception whose address
    324 /// is calculated from the supplied OurBaseException_t::unwindException
    325 /// member address. Handles (ignores), NULL pointers.
    326 /// @param expToDelete exception to delete
    327 void deleteOurException(OurUnwindException *expToDelete) {
    328 #ifdef DEBUG
    329   fprintf(stderr,
    330           "deleteOurException(...).\n");
    331 #endif
    332 
    333   if (expToDelete &&
    334       (expToDelete->exception_class == ourBaseExceptionClass)) {
    335 
    336     free(((char*) expToDelete) + ourBaseFromUnwindOffset);
    337   }
    338 }
    339 
    340 
    341 /// This function is the struct _Unwind_Exception API mandated delete function
    342 /// used by foreign exception handlers when deleting our exception
    343 /// (OurException), instances.
    344 /// @param reason See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html
    345 /// @unlink
    346 /// @param expToDelete exception instance to delete
    347 void deleteFromUnwindOurException(_Unwind_Reason_Code reason,
    348                                   OurUnwindException *expToDelete) {
    349 #ifdef DEBUG
    350   fprintf(stderr,
    351           "deleteFromUnwindOurException(...).\n");
    352 #endif
    353 
    354   deleteOurException(expToDelete);
    355 }
    356 
    357 
    358 /// Creates (allocates on the heap), an exception (OurException instance),
    359 /// of the supplied type info type.
    360 /// @param type type info type
    361 OurUnwindException *createOurException(int type) {
    362   size_t size = sizeof(OurException);
    363   OurException *ret = (OurException*) memset(malloc(size), 0, size);
    364   (ret->type).type = type;
    365   (ret->unwindException).exception_class = ourBaseExceptionClass;
    366   (ret->unwindException).exception_cleanup = deleteFromUnwindOurException;
    367 
    368   return(&(ret->unwindException));
    369 }
    370 
    371 
    372 /// Read a uleb128 encoded value and advance pointer
    373 /// See Variable Length Data in:
    374 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    375 /// @param data reference variable holding memory pointer to decode from
    376 /// @returns decoded value
    377 static uintptr_t readULEB128(const uint8_t **data) {
    378   uintptr_t result = 0;
    379   uintptr_t shift = 0;
    380   unsigned char byte;
    381   const uint8_t *p = *data;
    382 
    383   do {
    384     byte = *p++;
    385     result |= (byte & 0x7f) << shift;
    386     shift += 7;
    387   }
    388   while (byte & 0x80);
    389 
    390   *data = p;
    391 
    392   return result;
    393 }
    394 
    395 
    396 /// Read a sleb128 encoded value and advance pointer
    397 /// See Variable Length Data in:
    398 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    399 /// @param data reference variable holding memory pointer to decode from
    400 /// @returns decoded value
    401 static uintptr_t readSLEB128(const uint8_t **data) {
    402   uintptr_t result = 0;
    403   uintptr_t shift = 0;
    404   unsigned char byte;
    405   const uint8_t *p = *data;
    406 
    407   do {
    408     byte = *p++;
    409     result |= (byte & 0x7f) << shift;
    410     shift += 7;
    411   }
    412   while (byte & 0x80);
    413 
    414   *data = p;
    415 
    416   if ((byte & 0x40) && (shift < (sizeof(result) << 3))) {
    417     result |= (~0 << shift);
    418   }
    419 
    420   return result;
    421 }
    422 
    423 unsigned getEncodingSize(uint8_t Encoding) {
    424   if (Encoding == llvm::dwarf::DW_EH_PE_omit)
    425     return 0;
    426 
    427   switch (Encoding & 0x0F) {
    428   case llvm::dwarf::DW_EH_PE_absptr:
    429     return sizeof(uintptr_t);
    430   case llvm::dwarf::DW_EH_PE_udata2:
    431     return sizeof(uint16_t);
    432   case llvm::dwarf::DW_EH_PE_udata4:
    433     return sizeof(uint32_t);
    434   case llvm::dwarf::DW_EH_PE_udata8:
    435     return sizeof(uint64_t);
    436   case llvm::dwarf::DW_EH_PE_sdata2:
    437     return sizeof(int16_t);
    438   case llvm::dwarf::DW_EH_PE_sdata4:
    439     return sizeof(int32_t);
    440   case llvm::dwarf::DW_EH_PE_sdata8:
    441     return sizeof(int64_t);
    442   default:
    443     // not supported
    444     abort();
    445   }
    446 }
    447 
    448 /// Read a pointer encoded value and advance pointer
    449 /// See Variable Length Data in:
    450 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    451 /// @param data reference variable holding memory pointer to decode from
    452 /// @param encoding dwarf encoding type
    453 /// @returns decoded value
    454 static uintptr_t readEncodedPointer(const uint8_t **data, uint8_t encoding) {
    455   uintptr_t result = 0;
    456   const uint8_t *p = *data;
    457 
    458   if (encoding == llvm::dwarf::DW_EH_PE_omit)
    459     return(result);
    460 
    461   // first get value
    462   switch (encoding & 0x0F) {
    463     case llvm::dwarf::DW_EH_PE_absptr:
    464       result = *((uintptr_t*)p);
    465       p += sizeof(uintptr_t);
    466       break;
    467     case llvm::dwarf::DW_EH_PE_uleb128:
    468       result = readULEB128(&p);
    469       break;
    470       // Note: This case has not been tested
    471     case llvm::dwarf::DW_EH_PE_sleb128:
    472       result = readSLEB128(&p);
    473       break;
    474     case llvm::dwarf::DW_EH_PE_udata2:
    475       result = *((uint16_t*)p);
    476       p += sizeof(uint16_t);
    477       break;
    478     case llvm::dwarf::DW_EH_PE_udata4:
    479       result = *((uint32_t*)p);
    480       p += sizeof(uint32_t);
    481       break;
    482     case llvm::dwarf::DW_EH_PE_udata8:
    483       result = *((uint64_t*)p);
    484       p += sizeof(uint64_t);
    485       break;
    486     case llvm::dwarf::DW_EH_PE_sdata2:
    487       result = *((int16_t*)p);
    488       p += sizeof(int16_t);
    489       break;
    490     case llvm::dwarf::DW_EH_PE_sdata4:
    491       result = *((int32_t*)p);
    492       p += sizeof(int32_t);
    493       break;
    494     case llvm::dwarf::DW_EH_PE_sdata8:
    495       result = *((int64_t*)p);
    496       p += sizeof(int64_t);
    497       break;
    498     default:
    499       // not supported
    500       abort();
    501       break;
    502   }
    503 
    504   // then add relative offset
    505   switch (encoding & 0x70) {
    506     case llvm::dwarf::DW_EH_PE_absptr:
    507       // do nothing
    508       break;
    509     case llvm::dwarf::DW_EH_PE_pcrel:
    510       result += (uintptr_t)(*data);
    511       break;
    512     case llvm::dwarf::DW_EH_PE_textrel:
    513     case llvm::dwarf::DW_EH_PE_datarel:
    514     case llvm::dwarf::DW_EH_PE_funcrel:
    515     case llvm::dwarf::DW_EH_PE_aligned:
    516     default:
    517       // not supported
    518       abort();
    519       break;
    520   }
    521 
    522   // then apply indirection
    523   if (encoding & llvm::dwarf::DW_EH_PE_indirect) {
    524     result = *((uintptr_t*)result);
    525   }
    526 
    527   *data = p;
    528 
    529   return result;
    530 }
    531 
    532 
    533 /// Deals with Dwarf actions matching our type infos
    534 /// (OurExceptionType_t instances). Returns whether or not a dwarf emitted
    535 /// action matches the supplied exception type. If such a match succeeds,
    536 /// the resultAction argument will be set with > 0 index value. Only
    537 /// corresponding llvm.eh.selector type info arguments, cleanup arguments
    538 /// are supported. Filters are not supported.
    539 /// See Variable Length Data in:
    540 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    541 /// Also see @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    542 /// @param resultAction reference variable which will be set with result
    543 /// @param classInfo our array of type info pointers (to globals)
    544 /// @param actionEntry index into above type info array or 0 (clean up).
    545 ///        We do not support filters.
    546 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    547 ///        of thrown exception.
    548 /// @param exceptionObject thrown _Unwind_Exception instance.
    549 /// @returns whether or not a type info was found. False is returned if only
    550 ///          a cleanup was found
    551 static bool handleActionValue(int64_t *resultAction,
    552                               uint8_t TTypeEncoding,
    553                               const uint8_t *ClassInfo,
    554                               uintptr_t actionEntry,
    555                               uint64_t exceptionClass,
    556                               struct _Unwind_Exception *exceptionObject) {
    557   bool ret = false;
    558 
    559   if (!resultAction ||
    560       !exceptionObject ||
    561       (exceptionClass != ourBaseExceptionClass))
    562     return(ret);
    563 
    564   struct OurBaseException_t *excp = (struct OurBaseException_t*)
    565   (((char*) exceptionObject) + ourBaseFromUnwindOffset);
    566   struct OurExceptionType_t *excpType = &(excp->type);
    567   int type = excpType->type;
    568 
    569 #ifdef DEBUG
    570   fprintf(stderr,
    571           "handleActionValue(...): exceptionObject = <%p>, "
    572           "excp = <%p>.\n",
    573           (void*)exceptionObject,
    574           (void*)excp);
    575 #endif
    576 
    577   const uint8_t *actionPos = (uint8_t*) actionEntry,
    578   *tempActionPos;
    579   int64_t typeOffset = 0,
    580   actionOffset;
    581 
    582   for (int i = 0; true; ++i) {
    583     // Each emitted dwarf action corresponds to a 2 tuple of
    584     // type info address offset, and action offset to the next
    585     // emitted action.
    586     typeOffset = readSLEB128(&actionPos);
    587     tempActionPos = actionPos;
    588     actionOffset = readSLEB128(&tempActionPos);
    589 
    590 #ifdef DEBUG
    591     fprintf(stderr,
    592             "handleActionValue(...):typeOffset: <%" PRIi64 ">, "
    593             "actionOffset: <%" PRIi64 ">.\n",
    594             typeOffset,
    595             actionOffset);
    596 #endif
    597     assert((typeOffset >= 0) &&
    598            "handleActionValue(...):filters are not supported.");
    599 
    600     // Note: A typeOffset == 0 implies that a cleanup llvm.eh.selector
    601     //       argument has been matched.
    602     if (typeOffset > 0) {
    603 #ifdef DEBUG
    604       fprintf(stderr,
    605               "handleActionValue(...):actionValue <%d> found.\n",
    606               i);
    607 #endif
    608       unsigned EncSize = getEncodingSize(TTypeEncoding);
    609       const uint8_t *EntryP = ClassInfo - typeOffset * EncSize;
    610       uintptr_t P = readEncodedPointer(&EntryP, TTypeEncoding);
    611       struct OurExceptionType_t *ThisClassInfo =
    612         reinterpret_cast<struct OurExceptionType_t *>(P);
    613       if (ThisClassInfo->type == type) {
    614         *resultAction = i + 1;
    615         ret = true;
    616         break;
    617       }
    618     }
    619 
    620 #ifdef DEBUG
    621     fprintf(stderr,
    622             "handleActionValue(...):actionValue not found.\n");
    623 #endif
    624     if (!actionOffset)
    625       break;
    626 
    627     actionPos += actionOffset;
    628   }
    629 
    630   return(ret);
    631 }
    632 
    633 
    634 /// Deals with the Language specific data portion of the emitted dwarf code.
    635 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    636 /// @param version unsupported (ignored), unwind version
    637 /// @param lsda language specific data area
    638 /// @param _Unwind_Action actions minimally supported unwind stage
    639 ///        (forced specifically not supported)
    640 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    641 ///        of thrown exception.
    642 /// @param exceptionObject thrown _Unwind_Exception instance.
    643 /// @param context unwind system context
    644 /// @returns minimally supported unwinding control indicator
    645 static _Unwind_Reason_Code handleLsda(int version,
    646                                       const uint8_t *lsda,
    647                                       _Unwind_Action actions,
    648                                       uint64_t exceptionClass,
    649                                     struct _Unwind_Exception *exceptionObject,
    650                                       _Unwind_Context_t context) {
    651   _Unwind_Reason_Code ret = _URC_CONTINUE_UNWIND;
    652 
    653   if (!lsda)
    654     return(ret);
    655 
    656 #ifdef DEBUG
    657   fprintf(stderr,
    658           "handleLsda(...):lsda is non-zero.\n");
    659 #endif
    660 
    661   // Get the current instruction pointer and offset it before next
    662   // instruction in the current frame which threw the exception.
    663   uintptr_t pc = _Unwind_GetIP(context)-1;
    664 
    665   // Get beginning current frame's code (as defined by the
    666   // emitted dwarf code)
    667   uintptr_t funcStart = _Unwind_GetRegionStart(context);
    668   uintptr_t pcOffset = pc - funcStart;
    669   const uint8_t *ClassInfo = NULL;
    670 
    671   // Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding
    672   //       dwarf emission
    673 
    674   // Parse LSDA header.
    675   uint8_t lpStartEncoding = *lsda++;
    676 
    677   if (lpStartEncoding != llvm::dwarf::DW_EH_PE_omit) {
    678     readEncodedPointer(&lsda, lpStartEncoding);
    679   }
    680 
    681   uint8_t ttypeEncoding = *lsda++;
    682   uintptr_t classInfoOffset;
    683 
    684   if (ttypeEncoding != llvm::dwarf::DW_EH_PE_omit) {
    685     // Calculate type info locations in emitted dwarf code which
    686     // were flagged by type info arguments to llvm.eh.selector
    687     // intrinsic
    688     classInfoOffset = readULEB128(&lsda);
    689     ClassInfo = lsda + classInfoOffset;
    690   }
    691 
    692   // Walk call-site table looking for range that
    693   // includes current PC.
    694 
    695   uint8_t         callSiteEncoding = *lsda++;
    696   uint32_t        callSiteTableLength = readULEB128(&lsda);
    697   const uint8_t   *callSiteTableStart = lsda;
    698   const uint8_t   *callSiteTableEnd = callSiteTableStart +
    699   callSiteTableLength;
    700   const uint8_t   *actionTableStart = callSiteTableEnd;
    701   const uint8_t   *callSitePtr = callSiteTableStart;
    702 
    703   while (callSitePtr < callSiteTableEnd) {
    704     uintptr_t start = readEncodedPointer(&callSitePtr,
    705                                          callSiteEncoding);
    706     uintptr_t length = readEncodedPointer(&callSitePtr,
    707                                           callSiteEncoding);
    708     uintptr_t landingPad = readEncodedPointer(&callSitePtr,
    709                                               callSiteEncoding);
    710 
    711     // Note: Action value
    712     uintptr_t actionEntry = readULEB128(&callSitePtr);
    713 
    714     if (exceptionClass != ourBaseExceptionClass) {
    715       // We have been notified of a foreign exception being thrown,
    716       // and we therefore need to execute cleanup landing pads
    717       actionEntry = 0;
    718     }
    719 
    720     if (landingPad == 0) {
    721 #ifdef DEBUG
    722       fprintf(stderr,
    723               "handleLsda(...): No landing pad found.\n");
    724 #endif
    725 
    726       continue; // no landing pad for this entry
    727     }
    728 
    729     if (actionEntry) {
    730       actionEntry += ((uintptr_t) actionTableStart) - 1;
    731     }
    732     else {
    733 #ifdef DEBUG
    734       fprintf(stderr,
    735               "handleLsda(...):No action table found.\n");
    736 #endif
    737     }
    738 
    739     bool exceptionMatched = false;
    740 
    741     if ((start <= pcOffset) && (pcOffset < (start + length))) {
    742 #ifdef DEBUG
    743       fprintf(stderr,
    744               "handleLsda(...): Landing pad found.\n");
    745 #endif
    746       int64_t actionValue = 0;
    747 
    748       if (actionEntry) {
    749         exceptionMatched = handleActionValue(&actionValue,
    750                                              ttypeEncoding,
    751                                              ClassInfo,
    752                                              actionEntry,
    753                                              exceptionClass,
    754                                              exceptionObject);
    755       }
    756 
    757       if (!(actions & _UA_SEARCH_PHASE)) {
    758 #ifdef DEBUG
    759         fprintf(stderr,
    760                 "handleLsda(...): installed landing pad "
    761                 "context.\n");
    762 #endif
    763 
    764         // Found landing pad for the PC.
    765         // Set Instruction Pointer to so we re-enter function
    766         // at landing pad. The landing pad is created by the
    767         // compiler to take two parameters in registers.
    768         _Unwind_SetGR(context,
    769                       __builtin_eh_return_data_regno(0),
    770                       (uintptr_t)exceptionObject);
    771 
    772         // Note: this virtual register directly corresponds
    773         //       to the return of the llvm.eh.selector intrinsic
    774         if (!actionEntry || !exceptionMatched) {
    775           // We indicate cleanup only
    776           _Unwind_SetGR(context,
    777                         __builtin_eh_return_data_regno(1),
    778                         0);
    779         }
    780         else {
    781           // Matched type info index of llvm.eh.selector intrinsic
    782           // passed here.
    783           _Unwind_SetGR(context,
    784                         __builtin_eh_return_data_regno(1),
    785                         actionValue);
    786         }
    787 
    788         // To execute landing pad set here
    789         _Unwind_SetIP(context, funcStart + landingPad);
    790         ret = _URC_INSTALL_CONTEXT;
    791       }
    792       else if (exceptionMatched) {
    793 #ifdef DEBUG
    794         fprintf(stderr,
    795                 "handleLsda(...): setting handler found.\n");
    796 #endif
    797         ret = _URC_HANDLER_FOUND;
    798       }
    799       else {
    800         // Note: Only non-clean up handlers are marked as
    801         //       found. Otherwise the clean up handlers will be
    802         //       re-found and executed during the clean up
    803         //       phase.
    804 #ifdef DEBUG
    805         fprintf(stderr,
    806                 "handleLsda(...): cleanup handler found.\n");
    807 #endif
    808       }
    809 
    810       break;
    811     }
    812   }
    813 
    814   return(ret);
    815 }
    816 
    817 
    818 /// This is the personality function which is embedded (dwarf emitted), in the
    819 /// dwarf unwind info block. Again see: JITDwarfEmitter.cpp.
    820 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    821 /// @param version unsupported (ignored), unwind version
    822 /// @param _Unwind_Action actions minimally supported unwind stage
    823 ///        (forced specifically not supported)
    824 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    825 ///        of thrown exception.
    826 /// @param exceptionObject thrown _Unwind_Exception instance.
    827 /// @param context unwind system context
    828 /// @returns minimally supported unwinding control indicator
    829 _Unwind_Reason_Code ourPersonality(int version,
    830                                    _Unwind_Action actions,
    831                                    uint64_t exceptionClass,
    832                                    struct _Unwind_Exception *exceptionObject,
    833                                    _Unwind_Context_t context) {
    834 #ifdef DEBUG
    835   fprintf(stderr,
    836           "We are in ourPersonality(...):actions is <%d>.\n",
    837           actions);
    838 
    839   if (actions & _UA_SEARCH_PHASE) {
    840     fprintf(stderr, "ourPersonality(...):In search phase.\n");
    841   }
    842   else {
    843     fprintf(stderr, "ourPersonality(...):In non-search phase.\n");
    844   }
    845 #endif
    846 
    847   const uint8_t *lsda = _Unwind_GetLanguageSpecificData(context);
    848 
    849 #ifdef DEBUG
    850   fprintf(stderr,
    851           "ourPersonality(...):lsda = <%p>.\n",
    852           (void*)lsda);
    853 #endif
    854 
    855   // The real work of the personality function is captured here
    856   return(handleLsda(version,
    857                     lsda,
    858                     actions,
    859                     exceptionClass,
    860                     exceptionObject,
    861                     context));
    862 }
    863 
    864 
    865 /// Generates our _Unwind_Exception class from a given character array.
    866 /// thereby handling arbitrary lengths (not in standard), and handling
    867 /// embedded \0s.
    868 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    869 /// @param classChars char array to encode. NULL values not checkedf
    870 /// @param classCharsSize number of chars in classChars. Value is not checked.
    871 /// @returns class value
    872 uint64_t genClass(const unsigned char classChars[], size_t classCharsSize)
    873 {
    874   uint64_t ret = classChars[0];
    875 
    876   for (unsigned i = 1; i < classCharsSize; ++i) {
    877     ret <<= 8;
    878     ret += classChars[i];
    879   }
    880 
    881   return(ret);
    882 }
    883 
    884 } // extern "C"
    885 
    886 //
    887 // Runtime C Library functions End
    888 //
    889 
    890 //
    891 // Code generation functions
    892 //
    893 
    894 /// Generates code to print given constant string
    895 /// @param context llvm context
    896 /// @param module code for module instance
    897 /// @param builder builder instance
    898 /// @param toPrint string to print
    899 /// @param useGlobal A value of true (default) indicates a GlobalValue is
    900 ///        generated, and is used to hold the constant string. A value of
    901 ///        false indicates that the constant string will be stored on the
    902 ///        stack.
    903 void generateStringPrint(llvm::LLVMContext &context,
    904                          llvm::Module &module,
    905                          llvm::IRBuilder<> &builder,
    906                          std::string toPrint,
    907                          bool useGlobal = true) {
    908   llvm::Function *printFunct = module.getFunction("printStr");
    909 
    910   llvm::Value *stringVar;
    911   llvm::Constant *stringConstant =
    912   llvm::ConstantDataArray::getString(context, toPrint);
    913 
    914   if (useGlobal) {
    915     // Note: Does not work without allocation
    916     stringVar =
    917     new llvm::GlobalVariable(module,
    918                              stringConstant->getType(),
    919                              true,
    920                              llvm::GlobalValue::PrivateLinkage,
    921                              stringConstant,
    922                              "");
    923   }
    924   else {
    925     stringVar = builder.CreateAlloca(stringConstant->getType());
    926     builder.CreateStore(stringConstant, stringVar);
    927   }
    928 
    929   llvm::Value *cast = builder.CreatePointerCast(stringVar,
    930                                                 builder.getInt8PtrTy());
    931   builder.CreateCall(printFunct, cast);
    932 }
    933 
    934 
    935 /// Generates code to print given runtime integer according to constant
    936 /// string format, and a given print function.
    937 /// @param context llvm context
    938 /// @param module code for module instance
    939 /// @param builder builder instance
    940 /// @param printFunct function used to "print" integer
    941 /// @param toPrint string to print
    942 /// @param format printf like formating string for print
    943 /// @param useGlobal A value of true (default) indicates a GlobalValue is
    944 ///        generated, and is used to hold the constant string. A value of
    945 ///        false indicates that the constant string will be stored on the
    946 ///        stack.
    947 void generateIntegerPrint(llvm::LLVMContext &context,
    948                           llvm::Module &module,
    949                           llvm::IRBuilder<> &builder,
    950                           llvm::Function &printFunct,
    951                           llvm::Value &toPrint,
    952                           std::string format,
    953                           bool useGlobal = true) {
    954   llvm::Constant *stringConstant =
    955     llvm::ConstantDataArray::getString(context, format);
    956   llvm::Value *stringVar;
    957 
    958   if (useGlobal) {
    959     // Note: Does not seem to work without allocation
    960     stringVar =
    961     new llvm::GlobalVariable(module,
    962                              stringConstant->getType(),
    963                              true,
    964                              llvm::GlobalValue::PrivateLinkage,
    965                              stringConstant,
    966                              "");
    967   }
    968   else {
    969     stringVar = builder.CreateAlloca(stringConstant->getType());
    970     builder.CreateStore(stringConstant, stringVar);
    971   }
    972 
    973   llvm::Value *cast = builder.CreateBitCast(stringVar,
    974                                             builder.getInt8PtrTy());
    975   builder.CreateCall(&printFunct, {&toPrint, cast});
    976 }
    977 
    978 
    979 /// Generates code to handle finally block type semantics: always runs
    980 /// regardless of whether a thrown exception is passing through or the
    981 /// parent function is simply exiting. In addition to printing some state
    982 /// to stderr, this code will resume the exception handling--runs the
    983 /// unwind resume block, if the exception has not been previously caught
    984 /// by a catch clause, and will otherwise execute the end block (terminator
    985 /// block). In addition this function creates the corresponding function's
    986 /// stack storage for the exception pointer and catch flag status.
    987 /// @param context llvm context
    988 /// @param module code for module instance
    989 /// @param builder builder instance
    990 /// @param toAddTo parent function to add block to
    991 /// @param blockName block name of new "finally" block.
    992 /// @param functionId output id used for printing
    993 /// @param terminatorBlock terminator "end" block
    994 /// @param unwindResumeBlock unwind resume block
    995 /// @param exceptionCaughtFlag reference exception caught/thrown status storage
    996 /// @param exceptionStorage reference to exception pointer storage
    997 /// @param caughtResultStorage reference to landingpad result storage
    998 /// @returns newly created block
    999 static llvm::BasicBlock *createFinallyBlock(llvm::LLVMContext &context,
   1000                                             llvm::Module &module,
   1001                                             llvm::IRBuilder<> &builder,
   1002                                             llvm::Function &toAddTo,
   1003                                             std::string &blockName,
   1004                                             std::string &functionId,
   1005                                             llvm::BasicBlock &terminatorBlock,
   1006                                             llvm::BasicBlock &unwindResumeBlock,
   1007                                             llvm::Value **exceptionCaughtFlag,
   1008                                             llvm::Value **exceptionStorage,
   1009                                             llvm::Value **caughtResultStorage) {
   1010   assert(exceptionCaughtFlag &&
   1011          "ExceptionDemo::createFinallyBlock(...):exceptionCaughtFlag "
   1012          "is NULL");
   1013   assert(exceptionStorage &&
   1014          "ExceptionDemo::createFinallyBlock(...):exceptionStorage "
   1015          "is NULL");
   1016   assert(caughtResultStorage &&
   1017          "ExceptionDemo::createFinallyBlock(...):caughtResultStorage "
   1018          "is NULL");
   1019 
   1020   *exceptionCaughtFlag = createEntryBlockAlloca(toAddTo,
   1021                                          "exceptionCaught",
   1022                                          ourExceptionNotThrownState->getType(),
   1023                                          ourExceptionNotThrownState);
   1024 
   1025   llvm::PointerType *exceptionStorageType = builder.getInt8PtrTy();
   1026   *exceptionStorage = createEntryBlockAlloca(toAddTo,
   1027                                              "exceptionStorage",
   1028                                              exceptionStorageType,
   1029                                              llvm::ConstantPointerNull::get(
   1030                                                exceptionStorageType));
   1031   *caughtResultStorage = createEntryBlockAlloca(toAddTo,
   1032                                               "caughtResultStorage",
   1033                                               ourCaughtResultType,
   1034                                               llvm::ConstantAggregateZero::get(
   1035                                                 ourCaughtResultType));
   1036 
   1037   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
   1038                                                    blockName,
   1039                                                    &toAddTo);
   1040 
   1041   builder.SetInsertPoint(ret);
   1042 
   1043   std::ostringstream bufferToPrint;
   1044   bufferToPrint << "Gen: Executing finally block "
   1045     << blockName << " in " << functionId << "\n";
   1046   generateStringPrint(context,
   1047                       module,
   1048                       builder,
   1049                       bufferToPrint.str(),
   1050                       USE_GLOBAL_STR_CONSTS);
   1051 
   1052   llvm::SwitchInst *theSwitch = builder.CreateSwitch(builder.CreateLoad(
   1053                                                        *exceptionCaughtFlag),
   1054                                                      &terminatorBlock,
   1055                                                      2);
   1056   theSwitch->addCase(ourExceptionCaughtState, &terminatorBlock);
   1057   theSwitch->addCase(ourExceptionThrownState, &unwindResumeBlock);
   1058 
   1059   return(ret);
   1060 }
   1061 
   1062 
   1063 /// Generates catch block semantics which print a string to indicate type of
   1064 /// catch executed, sets an exception caught flag, and executes passed in
   1065 /// end block (terminator block).
   1066 /// @param context llvm context
   1067 /// @param module code for module instance
   1068 /// @param builder builder instance
   1069 /// @param toAddTo parent function to add block to
   1070 /// @param blockName block name of new "catch" block.
   1071 /// @param functionId output id used for printing
   1072 /// @param terminatorBlock terminator "end" block
   1073 /// @param exceptionCaughtFlag exception caught/thrown status
   1074 /// @returns newly created block
   1075 static llvm::BasicBlock *createCatchBlock(llvm::LLVMContext &context,
   1076                                           llvm::Module &module,
   1077                                           llvm::IRBuilder<> &builder,
   1078                                           llvm::Function &toAddTo,
   1079                                           std::string &blockName,
   1080                                           std::string &functionId,
   1081                                           llvm::BasicBlock &terminatorBlock,
   1082                                           llvm::Value &exceptionCaughtFlag) {
   1083 
   1084   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
   1085                                                    blockName,
   1086                                                    &toAddTo);
   1087 
   1088   builder.SetInsertPoint(ret);
   1089 
   1090   std::ostringstream bufferToPrint;
   1091   bufferToPrint << "Gen: Executing catch block "
   1092   << blockName
   1093   << " in "
   1094   << functionId
   1095   << std::endl;
   1096   generateStringPrint(context,
   1097                       module,
   1098                       builder,
   1099                       bufferToPrint.str(),
   1100                       USE_GLOBAL_STR_CONSTS);
   1101   builder.CreateStore(ourExceptionCaughtState, &exceptionCaughtFlag);
   1102   builder.CreateBr(&terminatorBlock);
   1103 
   1104   return(ret);
   1105 }
   1106 
   1107 
   1108 /// Generates a function which invokes a function (toInvoke) and, whose
   1109 /// unwind block will "catch" the type info types correspondingly held in the
   1110 /// exceptionTypesToCatch argument. If the toInvoke function throws an
   1111 /// exception which does not match any type info types contained in
   1112 /// exceptionTypesToCatch, the generated code will call _Unwind_Resume
   1113 /// with the raised exception. On the other hand the generated code will
   1114 /// normally exit if the toInvoke function does not throw an exception.
   1115 /// The generated "finally" block is always run regardless of the cause of
   1116 /// the generated function exit.
   1117 /// The generated function is returned after being verified.
   1118 /// @param module code for module instance
   1119 /// @param builder builder instance
   1120 /// @param fpm a function pass manager holding optional IR to IR
   1121 ///        transformations
   1122 /// @param toInvoke inner function to invoke
   1123 /// @param ourId id used to printing purposes
   1124 /// @param numExceptionsToCatch length of exceptionTypesToCatch array
   1125 /// @param exceptionTypesToCatch array of type info types to "catch"
   1126 /// @returns generated function
   1127 static llvm::Function *createCatchWrappedInvokeFunction(
   1128     llvm::Module &module, llvm::IRBuilder<> &builder,
   1129     llvm::legacy::FunctionPassManager &fpm, llvm::Function &toInvoke,
   1130     std::string ourId, unsigned numExceptionsToCatch,
   1131     unsigned exceptionTypesToCatch[]) {
   1132 
   1133   llvm::LLVMContext &context = module.getContext();
   1134   llvm::Function *toPrint32Int = module.getFunction("print32Int");
   1135 
   1136   ArgTypes argTypes;
   1137   argTypes.push_back(builder.getInt32Ty());
   1138 
   1139   ArgNames argNames;
   1140   argNames.push_back("exceptTypeToThrow");
   1141 
   1142   llvm::Function *ret = createFunction(module,
   1143                                        builder.getVoidTy(),
   1144                                        argTypes,
   1145                                        argNames,
   1146                                        ourId,
   1147                                        llvm::Function::ExternalLinkage,
   1148                                        false,
   1149                                        false);
   1150 
   1151   // Block which calls invoke
   1152   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
   1153                                                           "entry",
   1154                                                           ret);
   1155   // Normal block for invoke
   1156   llvm::BasicBlock *normalBlock = llvm::BasicBlock::Create(context,
   1157                                                            "normal",
   1158                                                            ret);
   1159   // Unwind block for invoke
   1160   llvm::BasicBlock *exceptionBlock = llvm::BasicBlock::Create(context,
   1161                                                               "exception",
   1162                                                               ret);
   1163 
   1164   // Block which routes exception to correct catch handler block
   1165   llvm::BasicBlock *exceptionRouteBlock = llvm::BasicBlock::Create(context,
   1166                                                              "exceptionRoute",
   1167                                                              ret);
   1168 
   1169   // Foreign exception handler
   1170   llvm::BasicBlock *externalExceptionBlock = llvm::BasicBlock::Create(context,
   1171                                                           "externalException",
   1172                                                           ret);
   1173 
   1174   // Block which calls _Unwind_Resume
   1175   llvm::BasicBlock *unwindResumeBlock = llvm::BasicBlock::Create(context,
   1176                                                                "unwindResume",
   1177                                                                ret);
   1178 
   1179   // Clean up block which delete exception if needed
   1180   llvm::BasicBlock *endBlock = llvm::BasicBlock::Create(context, "end", ret);
   1181 
   1182   std::string nextName;
   1183   std::vector<llvm::BasicBlock*> catchBlocks(numExceptionsToCatch);
   1184   llvm::Value *exceptionCaughtFlag = NULL;
   1185   llvm::Value *exceptionStorage = NULL;
   1186   llvm::Value *caughtResultStorage = NULL;
   1187 
   1188   // Finally block which will branch to unwindResumeBlock if
   1189   // exception is not caught. Initializes/allocates stack locations.
   1190   llvm::BasicBlock *finallyBlock = createFinallyBlock(context,
   1191                                                       module,
   1192                                                       builder,
   1193                                                       *ret,
   1194                                                       nextName = "finally",
   1195                                                       ourId,
   1196                                                       *endBlock,
   1197                                                       *unwindResumeBlock,
   1198                                                       &exceptionCaughtFlag,
   1199                                                       &exceptionStorage,
   1200                                                       &caughtResultStorage
   1201                                                       );
   1202 
   1203   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
   1204     nextName = ourTypeInfoNames[exceptionTypesToCatch[i]];
   1205 
   1206     // One catch block per type info to be caught
   1207     catchBlocks[i] = createCatchBlock(context,
   1208                                       module,
   1209                                       builder,
   1210                                       *ret,
   1211                                       nextName,
   1212                                       ourId,
   1213                                       *finallyBlock,
   1214                                       *exceptionCaughtFlag);
   1215   }
   1216 
   1217   // Entry Block
   1218 
   1219   builder.SetInsertPoint(entryBlock);
   1220 
   1221   std::vector<llvm::Value*> args;
   1222   args.push_back(namedValues["exceptTypeToThrow"]);
   1223   builder.CreateInvoke(&toInvoke,
   1224                        normalBlock,
   1225                        exceptionBlock,
   1226                        args);
   1227 
   1228   // End Block
   1229 
   1230   builder.SetInsertPoint(endBlock);
   1231 
   1232   generateStringPrint(context,
   1233                       module,
   1234                       builder,
   1235                       "Gen: In end block: exiting in " + ourId + ".\n",
   1236                       USE_GLOBAL_STR_CONSTS);
   1237   llvm::Function *deleteOurException = module.getFunction("deleteOurException");
   1238 
   1239   // Note: function handles NULL exceptions
   1240   builder.CreateCall(deleteOurException,
   1241                      builder.CreateLoad(exceptionStorage));
   1242   builder.CreateRetVoid();
   1243 
   1244   // Normal Block
   1245 
   1246   builder.SetInsertPoint(normalBlock);
   1247 
   1248   generateStringPrint(context,
   1249                       module,
   1250                       builder,
   1251                       "Gen: No exception in " + ourId + "!\n",
   1252                       USE_GLOBAL_STR_CONSTS);
   1253 
   1254   // Finally block is always called
   1255   builder.CreateBr(finallyBlock);
   1256 
   1257   // Unwind Resume Block
   1258 
   1259   builder.SetInsertPoint(unwindResumeBlock);
   1260 
   1261   builder.CreateResume(builder.CreateLoad(caughtResultStorage));
   1262 
   1263   // Exception Block
   1264 
   1265   builder.SetInsertPoint(exceptionBlock);
   1266 
   1267   llvm::Function *personality = module.getFunction("ourPersonality");
   1268   ret->setPersonalityFn(personality);
   1269 
   1270   llvm::LandingPadInst *caughtResult =
   1271     builder.CreateLandingPad(ourCaughtResultType,
   1272                              numExceptionsToCatch,
   1273                              "landingPad");
   1274 
   1275   caughtResult->setCleanup(true);
   1276 
   1277   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
   1278     // Set up type infos to be caught
   1279     caughtResult->addClause(module.getGlobalVariable(
   1280                              ourTypeInfoNames[exceptionTypesToCatch[i]]));
   1281   }
   1282 
   1283   llvm::Value *unwindException = builder.CreateExtractValue(caughtResult, 0);
   1284   llvm::Value *retTypeInfoIndex = builder.CreateExtractValue(caughtResult, 1);
   1285 
   1286   // FIXME: Redundant storage which, beyond utilizing value of
   1287   //        caughtResultStore for unwindException storage, may be alleviated
   1288   //        altogether with a block rearrangement
   1289   builder.CreateStore(caughtResult, caughtResultStorage);
   1290   builder.CreateStore(unwindException, exceptionStorage);
   1291   builder.CreateStore(ourExceptionThrownState, exceptionCaughtFlag);
   1292 
   1293   // Retrieve exception_class member from thrown exception
   1294   // (_Unwind_Exception instance). This member tells us whether or not
   1295   // the exception is foreign.
   1296   llvm::Value *unwindExceptionClass =
   1297       builder.CreateLoad(builder.CreateStructGEP(
   1298           ourUnwindExceptionType,
   1299           builder.CreatePointerCast(unwindException,
   1300                                     ourUnwindExceptionType->getPointerTo()),
   1301           0));
   1302 
   1303   // Branch to the externalExceptionBlock if the exception is foreign or
   1304   // to a catch router if not. Either way the finally block will be run.
   1305   builder.CreateCondBr(builder.CreateICmpEQ(unwindExceptionClass,
   1306                             llvm::ConstantInt::get(builder.getInt64Ty(),
   1307                                                    ourBaseExceptionClass)),
   1308                        exceptionRouteBlock,
   1309                        externalExceptionBlock);
   1310 
   1311   // External Exception Block
   1312 
   1313   builder.SetInsertPoint(externalExceptionBlock);
   1314 
   1315   generateStringPrint(context,
   1316                       module,
   1317                       builder,
   1318                       "Gen: Foreign exception received.\n",
   1319                       USE_GLOBAL_STR_CONSTS);
   1320 
   1321   // Branch to the finally block
   1322   builder.CreateBr(finallyBlock);
   1323 
   1324   // Exception Route Block
   1325 
   1326   builder.SetInsertPoint(exceptionRouteBlock);
   1327 
   1328   // Casts exception pointer (_Unwind_Exception instance) to parent
   1329   // (OurException instance).
   1330   //
   1331   // Note: ourBaseFromUnwindOffset is usually negative
   1332   llvm::Value *typeInfoThrown = builder.CreatePointerCast(
   1333                                   builder.CreateConstGEP1_64(unwindException,
   1334                                                        ourBaseFromUnwindOffset),
   1335                                   ourExceptionType->getPointerTo());
   1336 
   1337   // Retrieve thrown exception type info type
   1338   //
   1339   // Note: Index is not relative to pointer but instead to structure
   1340   //       unlike a true getelementptr (GEP) instruction
   1341   typeInfoThrown = builder.CreateStructGEP(ourExceptionType, typeInfoThrown, 0);
   1342 
   1343   llvm::Value *typeInfoThrownType =
   1344       builder.CreateStructGEP(builder.getInt8PtrTy(), typeInfoThrown, 0);
   1345 
   1346   generateIntegerPrint(context,
   1347                        module,
   1348                        builder,
   1349                        *toPrint32Int,
   1350                        *(builder.CreateLoad(typeInfoThrownType)),
   1351                        "Gen: Exception type <%d> received (stack unwound) "
   1352                        " in " +
   1353                        ourId +
   1354                        ".\n",
   1355                        USE_GLOBAL_STR_CONSTS);
   1356 
   1357   // Route to matched type info catch block or run cleanup finally block
   1358   llvm::SwitchInst *switchToCatchBlock = builder.CreateSwitch(retTypeInfoIndex,
   1359                                                           finallyBlock,
   1360                                                           numExceptionsToCatch);
   1361 
   1362   unsigned nextTypeToCatch;
   1363 
   1364   for (unsigned i = 1; i <= numExceptionsToCatch; ++i) {
   1365     nextTypeToCatch = i - 1;
   1366     switchToCatchBlock->addCase(llvm::ConstantInt::get(
   1367                                    llvm::Type::getInt32Ty(context), i),
   1368                                 catchBlocks[nextTypeToCatch]);
   1369   }
   1370 
   1371   llvm::verifyFunction(*ret);
   1372   fpm.run(*ret);
   1373 
   1374   return(ret);
   1375 }
   1376 
   1377 
   1378 /// Generates function which throws either an exception matched to a runtime
   1379 /// determined type info type (argument to generated function), or if this
   1380 /// runtime value matches nativeThrowType, throws a foreign exception by
   1381 /// calling nativeThrowFunct.
   1382 /// @param module code for module instance
   1383 /// @param builder builder instance
   1384 /// @param fpm a function pass manager holding optional IR to IR
   1385 ///        transformations
   1386 /// @param ourId id used to printing purposes
   1387 /// @param nativeThrowType a runtime argument of this value results in
   1388 ///        nativeThrowFunct being called to generate/throw exception.
   1389 /// @param nativeThrowFunct function which will throw a foreign exception
   1390 ///        if the above nativeThrowType matches generated function's arg.
   1391 /// @returns generated function
   1392 static llvm::Function *
   1393 createThrowExceptionFunction(llvm::Module &module, llvm::IRBuilder<> &builder,
   1394                              llvm::legacy::FunctionPassManager &fpm,
   1395                              std::string ourId, int32_t nativeThrowType,
   1396                              llvm::Function &nativeThrowFunct) {
   1397   llvm::LLVMContext &context = module.getContext();
   1398   namedValues.clear();
   1399   ArgTypes unwindArgTypes;
   1400   unwindArgTypes.push_back(builder.getInt32Ty());
   1401   ArgNames unwindArgNames;
   1402   unwindArgNames.push_back("exceptTypeToThrow");
   1403 
   1404   llvm::Function *ret = createFunction(module,
   1405                                        builder.getVoidTy(),
   1406                                        unwindArgTypes,
   1407                                        unwindArgNames,
   1408                                        ourId,
   1409                                        llvm::Function::ExternalLinkage,
   1410                                        false,
   1411                                        false);
   1412 
   1413   // Throws either one of our exception or a native C++ exception depending
   1414   // on a runtime argument value containing a type info type.
   1415   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
   1416                                                           "entry",
   1417                                                           ret);
   1418   // Throws a foreign exception
   1419   llvm::BasicBlock *nativeThrowBlock = llvm::BasicBlock::Create(context,
   1420                                                                 "nativeThrow",
   1421                                                                 ret);
   1422   // Throws one of our Exceptions
   1423   llvm::BasicBlock *generatedThrowBlock = llvm::BasicBlock::Create(context,
   1424                                                              "generatedThrow",
   1425                                                              ret);
   1426   // Retrieved runtime type info type to throw
   1427   llvm::Value *exceptionType = namedValues["exceptTypeToThrow"];
   1428 
   1429   // nativeThrowBlock block
   1430 
   1431   builder.SetInsertPoint(nativeThrowBlock);
   1432 
   1433   // Throws foreign exception
   1434   builder.CreateCall(&nativeThrowFunct, exceptionType);
   1435   builder.CreateUnreachable();
   1436 
   1437   // entry block
   1438 
   1439   builder.SetInsertPoint(entryBlock);
   1440 
   1441   llvm::Function *toPrint32Int = module.getFunction("print32Int");
   1442   generateIntegerPrint(context,
   1443                        module,
   1444                        builder,
   1445                        *toPrint32Int,
   1446                        *exceptionType,
   1447                        "\nGen: About to throw exception type <%d> in " +
   1448                        ourId +
   1449                        ".\n",
   1450                        USE_GLOBAL_STR_CONSTS);
   1451 
   1452   // Switches on runtime type info type value to determine whether or not
   1453   // a foreign exception is thrown. Defaults to throwing one of our
   1454   // generated exceptions.
   1455   llvm::SwitchInst *theSwitch = builder.CreateSwitch(exceptionType,
   1456                                                      generatedThrowBlock,
   1457                                                      1);
   1458 
   1459   theSwitch->addCase(llvm::ConstantInt::get(llvm::Type::getInt32Ty(context),
   1460                                             nativeThrowType),
   1461                      nativeThrowBlock);
   1462 
   1463   // generatedThrow block
   1464 
   1465   builder.SetInsertPoint(generatedThrowBlock);
   1466 
   1467   llvm::Function *createOurException = module.getFunction("createOurException");
   1468   llvm::Function *raiseOurException = module.getFunction(
   1469                                         "_Unwind_RaiseException");
   1470 
   1471   // Creates exception to throw with runtime type info type.
   1472   llvm::Value *exception = builder.CreateCall(createOurException,
   1473                                               namedValues["exceptTypeToThrow"]);
   1474 
   1475   // Throw generated Exception
   1476   builder.CreateCall(raiseOurException, exception);
   1477   builder.CreateUnreachable();
   1478 
   1479   llvm::verifyFunction(*ret);
   1480   fpm.run(*ret);
   1481 
   1482   return(ret);
   1483 }
   1484 
   1485 static void createStandardUtilityFunctions(unsigned numTypeInfos,
   1486                                            llvm::Module &module,
   1487                                            llvm::IRBuilder<> &builder);
   1488 
   1489 /// Creates test code by generating and organizing these functions into the
   1490 /// test case. The test case consists of an outer function setup to invoke
   1491 /// an inner function within an environment having multiple catch and single
   1492 /// finally blocks. This inner function is also setup to invoke a throw
   1493 /// function within an evironment similar in nature to the outer function's
   1494 /// catch and finally blocks. Each of these two functions catch mutually
   1495 /// exclusive subsets (even or odd) of the type info types configured
   1496 /// for this this. All generated functions have a runtime argument which
   1497 /// holds a type info type to throw that each function takes and passes it
   1498 /// to the inner one if such a inner function exists. This type info type is
   1499 /// looked at by the generated throw function to see whether or not it should
   1500 /// throw a generated exception with the same type info type, or instead call
   1501 /// a supplied a function which in turn will throw a foreign exception.
   1502 /// @param module code for module instance
   1503 /// @param builder builder instance
   1504 /// @param fpm a function pass manager holding optional IR to IR
   1505 ///        transformations
   1506 /// @param nativeThrowFunctName name of external function which will throw
   1507 ///        a foreign exception
   1508 /// @returns outermost generated test function.
   1509 llvm::Function *
   1510 createUnwindExceptionTest(llvm::Module &module, llvm::IRBuilder<> &builder,
   1511                           llvm::legacy::FunctionPassManager &fpm,
   1512                           std::string nativeThrowFunctName) {
   1513   // Number of type infos to generate
   1514   unsigned numTypeInfos = 6;
   1515 
   1516   // Initialze intrisics and external functions to use along with exception
   1517   // and type info globals.
   1518   createStandardUtilityFunctions(numTypeInfos,
   1519                                  module,
   1520                                  builder);
   1521   llvm::Function *nativeThrowFunct = module.getFunction(nativeThrowFunctName);
   1522 
   1523   // Create exception throw function using the value ~0 to cause
   1524   // foreign exceptions to be thrown.
   1525   llvm::Function *throwFunct = createThrowExceptionFunction(module,
   1526                                                             builder,
   1527                                                             fpm,
   1528                                                             "throwFunct",
   1529                                                             ~0,
   1530                                                             *nativeThrowFunct);
   1531   // Inner function will catch even type infos
   1532   unsigned innerExceptionTypesToCatch[] = {6, 2, 4};
   1533   size_t numExceptionTypesToCatch = sizeof(innerExceptionTypesToCatch) /
   1534                                     sizeof(unsigned);
   1535 
   1536   // Generate inner function.
   1537   llvm::Function *innerCatchFunct = createCatchWrappedInvokeFunction(module,
   1538                                                     builder,
   1539                                                     fpm,
   1540                                                     *throwFunct,
   1541                                                     "innerCatchFunct",
   1542                                                     numExceptionTypesToCatch,
   1543                                                     innerExceptionTypesToCatch);
   1544 
   1545   // Outer function will catch odd type infos
   1546   unsigned outerExceptionTypesToCatch[] = {3, 1, 5};
   1547   numExceptionTypesToCatch = sizeof(outerExceptionTypesToCatch) /
   1548   sizeof(unsigned);
   1549 
   1550   // Generate outer function
   1551   llvm::Function *outerCatchFunct = createCatchWrappedInvokeFunction(module,
   1552                                                     builder,
   1553                                                     fpm,
   1554                                                     *innerCatchFunct,
   1555                                                     "outerCatchFunct",
   1556                                                     numExceptionTypesToCatch,
   1557                                                     outerExceptionTypesToCatch);
   1558 
   1559   // Return outer function to run
   1560   return(outerCatchFunct);
   1561 }
   1562 
   1563 namespace {
   1564 /// Represents our foreign exceptions
   1565 class OurCppRunException : public std::runtime_error {
   1566 public:
   1567   OurCppRunException(const std::string reason) :
   1568   std::runtime_error(reason) {}
   1569 
   1570   OurCppRunException (const OurCppRunException &toCopy) :
   1571   std::runtime_error(toCopy) {}
   1572 
   1573   OurCppRunException &operator = (const OurCppRunException &toCopy) {
   1574     return(reinterpret_cast<OurCppRunException&>(
   1575                                  std::runtime_error::operator=(toCopy)));
   1576   }
   1577 
   1578   ~OurCppRunException(void) throw() override {}
   1579 };
   1580 } // end anonymous namespace
   1581 
   1582 /// Throws foreign C++ exception.
   1583 /// @param ignoreIt unused parameter that allows function to match implied
   1584 ///        generated function contract.
   1585 extern "C"
   1586 void throwCppException (int32_t ignoreIt) {
   1587   throw(OurCppRunException("thrown by throwCppException(...)"));
   1588 }
   1589 
   1590 typedef void (*OurExceptionThrowFunctType) (int32_t typeToThrow);
   1591 
   1592 /// This is a test harness which runs test by executing generated
   1593 /// function with a type info type to throw. Harness wraps the execution
   1594 /// of generated function in a C++ try catch clause.
   1595 /// @param engine execution engine to use for executing generated function.
   1596 ///        This demo program expects this to be a JIT instance for demo
   1597 ///        purposes.
   1598 /// @param function generated test function to run
   1599 /// @param typeToThrow type info type of generated exception to throw, or
   1600 ///        indicator to cause foreign exception to be thrown.
   1601 static
   1602 void runExceptionThrow(llvm::ExecutionEngine *engine,
   1603                        llvm::Function *function,
   1604                        int32_t typeToThrow) {
   1605 
   1606   // Find test's function pointer
   1607   OurExceptionThrowFunctType functPtr =
   1608     reinterpret_cast<OurExceptionThrowFunctType>(
   1609        reinterpret_cast<intptr_t>(engine->getPointerToFunction(function)));
   1610 
   1611   try {
   1612     // Run test
   1613     (*functPtr)(typeToThrow);
   1614   }
   1615   catch (OurCppRunException exc) {
   1616     // Catch foreign C++ exception
   1617     fprintf(stderr,
   1618             "\nrunExceptionThrow(...):In C++ catch OurCppRunException "
   1619             "with reason: %s.\n",
   1620             exc.what());
   1621   }
   1622   catch (...) {
   1623     // Catch all exceptions including our generated ones. This latter
   1624     // functionality works according to the example in rules 1.6.4 of
   1625     // http://mentorembedded.github.com/cxx-abi/abi-eh.html (v1.22),
   1626     // given that these will be exceptions foreign to C++
   1627     // (the _Unwind_Exception::exception_class should be different from
   1628     // the one used by C++).
   1629     fprintf(stderr,
   1630             "\nrunExceptionThrow(...):In C++ catch all.\n");
   1631   }
   1632 }
   1633 
   1634 //
   1635 // End test functions
   1636 //
   1637 
   1638 typedef llvm::ArrayRef<llvm::Type*> TypeArray;
   1639 
   1640 /// This initialization routine creates type info globals and
   1641 /// adds external function declarations to module.
   1642 /// @param numTypeInfos number of linear type info associated type info types
   1643 ///        to create as GlobalVariable instances, starting with the value 1.
   1644 /// @param module code for module instance
   1645 /// @param builder builder instance
   1646 static void createStandardUtilityFunctions(unsigned numTypeInfos,
   1647                                            llvm::Module &module,
   1648                                            llvm::IRBuilder<> &builder) {
   1649 
   1650   llvm::LLVMContext &context = module.getContext();
   1651 
   1652   // Exception initializations
   1653 
   1654   // Setup exception catch state
   1655   ourExceptionNotThrownState =
   1656     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 0),
   1657   ourExceptionThrownState =
   1658     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 1),
   1659   ourExceptionCaughtState =
   1660     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 2),
   1661 
   1662 
   1663 
   1664   // Create our type info type
   1665   ourTypeInfoType = llvm::StructType::get(context,
   1666                                           TypeArray(builder.getInt32Ty()));
   1667 
   1668   llvm::Type *caughtResultFieldTypes[] = {
   1669     builder.getInt8PtrTy(),
   1670     builder.getInt32Ty()
   1671   };
   1672 
   1673   // Create our landingpad result type
   1674   ourCaughtResultType = llvm::StructType::get(context,
   1675                                             TypeArray(caughtResultFieldTypes));
   1676 
   1677   // Create OurException type
   1678   ourExceptionType = llvm::StructType::get(context,
   1679                                            TypeArray(ourTypeInfoType));
   1680 
   1681   // Create portion of _Unwind_Exception type
   1682   //
   1683   // Note: Declaring only a portion of the _Unwind_Exception struct.
   1684   //       Does this cause problems?
   1685   ourUnwindExceptionType =
   1686     llvm::StructType::get(context,
   1687                     TypeArray(builder.getInt64Ty()));
   1688 
   1689   struct OurBaseException_t dummyException;
   1690 
   1691   // Calculate offset of OurException::unwindException member.
   1692   ourBaseFromUnwindOffset = ((uintptr_t) &dummyException) -
   1693                             ((uintptr_t) &(dummyException.unwindException));
   1694 
   1695 #ifdef DEBUG
   1696   fprintf(stderr,
   1697           "createStandardUtilityFunctions(...):ourBaseFromUnwindOffset "
   1698           "= %" PRIi64 ", sizeof(struct OurBaseException_t) - "
   1699           "sizeof(struct _Unwind_Exception) = %lu.\n",
   1700           ourBaseFromUnwindOffset,
   1701           sizeof(struct OurBaseException_t) -
   1702           sizeof(struct _Unwind_Exception));
   1703 #endif
   1704 
   1705   size_t numChars = sizeof(ourBaseExcpClassChars) / sizeof(char);
   1706 
   1707   // Create our _Unwind_Exception::exception_class value
   1708   ourBaseExceptionClass = genClass(ourBaseExcpClassChars, numChars);
   1709 
   1710   // Type infos
   1711 
   1712   std::string baseStr = "typeInfo", typeInfoName;
   1713   std::ostringstream typeInfoNameBuilder;
   1714   std::vector<llvm::Constant*> structVals;
   1715 
   1716   llvm::Constant *nextStruct;
   1717 
   1718   // Generate each type info
   1719   //
   1720   // Note: First type info is not used.
   1721   for (unsigned i = 0; i <= numTypeInfos; ++i) {
   1722     structVals.clear();
   1723     structVals.push_back(llvm::ConstantInt::get(builder.getInt32Ty(), i));
   1724     nextStruct = llvm::ConstantStruct::get(ourTypeInfoType, structVals);
   1725 
   1726     typeInfoNameBuilder.str("");
   1727     typeInfoNameBuilder << baseStr << i;
   1728     typeInfoName = typeInfoNameBuilder.str();
   1729 
   1730     // Note: Does not seem to work without allocation
   1731     new llvm::GlobalVariable(module,
   1732                              ourTypeInfoType,
   1733                              true,
   1734                              llvm::GlobalValue::ExternalLinkage,
   1735                              nextStruct,
   1736                              typeInfoName);
   1737 
   1738     ourTypeInfoNames.push_back(typeInfoName);
   1739     ourTypeInfoNamesIndex[i] = typeInfoName;
   1740   }
   1741 
   1742   ArgNames argNames;
   1743   ArgTypes argTypes;
   1744   llvm::Function *funct = NULL;
   1745 
   1746   // print32Int
   1747 
   1748   llvm::Type *retType = builder.getVoidTy();
   1749 
   1750   argTypes.clear();
   1751   argTypes.push_back(builder.getInt32Ty());
   1752   argTypes.push_back(builder.getInt8PtrTy());
   1753 
   1754   argNames.clear();
   1755 
   1756   createFunction(module,
   1757                  retType,
   1758                  argTypes,
   1759                  argNames,
   1760                  "print32Int",
   1761                  llvm::Function::ExternalLinkage,
   1762                  true,
   1763                  false);
   1764 
   1765   // print64Int
   1766 
   1767   retType = builder.getVoidTy();
   1768 
   1769   argTypes.clear();
   1770   argTypes.push_back(builder.getInt64Ty());
   1771   argTypes.push_back(builder.getInt8PtrTy());
   1772 
   1773   argNames.clear();
   1774 
   1775   createFunction(module,
   1776                  retType,
   1777                  argTypes,
   1778                  argNames,
   1779                  "print64Int",
   1780                  llvm::Function::ExternalLinkage,
   1781                  true,
   1782                  false);
   1783 
   1784   // printStr
   1785 
   1786   retType = builder.getVoidTy();
   1787 
   1788   argTypes.clear();
   1789   argTypes.push_back(builder.getInt8PtrTy());
   1790 
   1791   argNames.clear();
   1792 
   1793   createFunction(module,
   1794                  retType,
   1795                  argTypes,
   1796                  argNames,
   1797                  "printStr",
   1798                  llvm::Function::ExternalLinkage,
   1799                  true,
   1800                  false);
   1801 
   1802   // throwCppException
   1803 
   1804   retType = builder.getVoidTy();
   1805 
   1806   argTypes.clear();
   1807   argTypes.push_back(builder.getInt32Ty());
   1808 
   1809   argNames.clear();
   1810 
   1811   createFunction(module,
   1812                  retType,
   1813                  argTypes,
   1814                  argNames,
   1815                  "throwCppException",
   1816                  llvm::Function::ExternalLinkage,
   1817                  true,
   1818                  false);
   1819 
   1820   // deleteOurException
   1821 
   1822   retType = builder.getVoidTy();
   1823 
   1824   argTypes.clear();
   1825   argTypes.push_back(builder.getInt8PtrTy());
   1826 
   1827   argNames.clear();
   1828 
   1829   createFunction(module,
   1830                  retType,
   1831                  argTypes,
   1832                  argNames,
   1833                  "deleteOurException",
   1834                  llvm::Function::ExternalLinkage,
   1835                  true,
   1836                  false);
   1837 
   1838   // createOurException
   1839 
   1840   retType = builder.getInt8PtrTy();
   1841 
   1842   argTypes.clear();
   1843   argTypes.push_back(builder.getInt32Ty());
   1844 
   1845   argNames.clear();
   1846 
   1847   createFunction(module,
   1848                  retType,
   1849                  argTypes,
   1850                  argNames,
   1851                  "createOurException",
   1852                  llvm::Function::ExternalLinkage,
   1853                  true,
   1854                  false);
   1855 
   1856   // _Unwind_RaiseException
   1857 
   1858   retType = builder.getInt32Ty();
   1859 
   1860   argTypes.clear();
   1861   argTypes.push_back(builder.getInt8PtrTy());
   1862 
   1863   argNames.clear();
   1864 
   1865   funct = createFunction(module,
   1866                          retType,
   1867                          argTypes,
   1868                          argNames,
   1869                          "_Unwind_RaiseException",
   1870                          llvm::Function::ExternalLinkage,
   1871                          true,
   1872                          false);
   1873 
   1874   funct->setDoesNotReturn();
   1875 
   1876   // _Unwind_Resume
   1877 
   1878   retType = builder.getInt32Ty();
   1879 
   1880   argTypes.clear();
   1881   argTypes.push_back(builder.getInt8PtrTy());
   1882 
   1883   argNames.clear();
   1884 
   1885   funct = createFunction(module,
   1886                          retType,
   1887                          argTypes,
   1888                          argNames,
   1889                          "_Unwind_Resume",
   1890                          llvm::Function::ExternalLinkage,
   1891                          true,
   1892                          false);
   1893 
   1894   funct->setDoesNotReturn();
   1895 
   1896   // ourPersonality
   1897 
   1898   retType = builder.getInt32Ty();
   1899 
   1900   argTypes.clear();
   1901   argTypes.push_back(builder.getInt32Ty());
   1902   argTypes.push_back(builder.getInt32Ty());
   1903   argTypes.push_back(builder.getInt64Ty());
   1904   argTypes.push_back(builder.getInt8PtrTy());
   1905   argTypes.push_back(builder.getInt8PtrTy());
   1906 
   1907   argNames.clear();
   1908 
   1909   createFunction(module,
   1910                  retType,
   1911                  argTypes,
   1912                  argNames,
   1913                  "ourPersonality",
   1914                  llvm::Function::ExternalLinkage,
   1915                  true,
   1916                  false);
   1917 
   1918   // llvm.eh.typeid.for intrinsic
   1919 
   1920   getDeclaration(&module, llvm::Intrinsic::eh_typeid_for);
   1921 }
   1922 
   1923 
   1924 //===----------------------------------------------------------------------===//
   1925 // Main test driver code.
   1926 //===----------------------------------------------------------------------===//
   1927 
   1928 /// Demo main routine which takes the type info types to throw. A test will
   1929 /// be run for each given type info type. While type info types with the value
   1930 /// of -1 will trigger a foreign C++ exception to be thrown; type info types
   1931 /// <= 6 and >= 1 will be caught by test functions; and type info types > 6
   1932 /// will result in exceptions which pass through to the test harness. All other
   1933 /// type info types are not supported and could cause a crash.
   1934 int main(int argc, char *argv[]) {
   1935   if (argc == 1) {
   1936     fprintf(stderr,
   1937             "\nUsage: ExceptionDemo <exception type to throw> "
   1938             "[<type 2>...<type n>].\n"
   1939             "   Each type must have the value of 1 - 6 for "
   1940             "generated exceptions to be caught;\n"
   1941             "   the value -1 for foreign C++ exceptions to be "
   1942             "generated and thrown;\n"
   1943             "   or the values > 6 for exceptions to be ignored.\n"
   1944             "\nTry: ExceptionDemo 2 3 7 -1\n"
   1945             "   for a full test.\n\n");
   1946     return(0);
   1947   }
   1948 
   1949   // If not set, exception handling will not be turned on
   1950   llvm::TargetOptions Opts;
   1951 
   1952   llvm::InitializeNativeTarget();
   1953   llvm::InitializeNativeTargetAsmPrinter();
   1954   llvm::LLVMContext Context;
   1955   llvm::IRBuilder<> theBuilder(Context);
   1956 
   1957   // Make the module, which holds all the code.
   1958   std::unique_ptr<llvm::Module> Owner =
   1959       llvm::make_unique<llvm::Module>("my cool jit", Context);
   1960   llvm::Module *module = Owner.get();
   1961 
   1962   std::unique_ptr<llvm::RTDyldMemoryManager> MemMgr(new llvm::SectionMemoryManager());
   1963 
   1964   // Build engine with JIT
   1965   llvm::EngineBuilder factory(std::move(Owner));
   1966   factory.setEngineKind(llvm::EngineKind::JIT);
   1967   factory.setTargetOptions(Opts);
   1968   factory.setMCJITMemoryManager(std::move(MemMgr));
   1969   llvm::ExecutionEngine *executionEngine = factory.create();
   1970 
   1971   {
   1972     llvm::legacy::FunctionPassManager fpm(module);
   1973 
   1974     // Set up the optimizer pipeline.
   1975     // Start with registering info about how the
   1976     // target lays out data structures.
   1977     module->setDataLayout(executionEngine->getDataLayout());
   1978 
   1979     // Optimizations turned on
   1980 #ifdef ADD_OPT_PASSES
   1981 
   1982     // Basic AliasAnslysis support for GVN.
   1983     fpm.add(llvm::createBasicAliasAnalysisPass());
   1984 
   1985     // Promote allocas to registers.
   1986     fpm.add(llvm::createPromoteMemoryToRegisterPass());
   1987 
   1988     // Do simple "peephole" optimizations and bit-twiddling optzns.
   1989     fpm.add(llvm::createInstructionCombiningPass());
   1990 
   1991     // Reassociate expressions.
   1992     fpm.add(llvm::createReassociatePass());
   1993 
   1994     // Eliminate Common SubExpressions.
   1995     fpm.add(llvm::createGVNPass());
   1996 
   1997     // Simplify the control flow graph (deleting unreachable
   1998     // blocks, etc).
   1999     fpm.add(llvm::createCFGSimplificationPass());
   2000 #endif  // ADD_OPT_PASSES
   2001 
   2002     fpm.doInitialization();
   2003 
   2004     // Generate test code using function throwCppException(...) as
   2005     // the function which throws foreign exceptions.
   2006     llvm::Function *toRun =
   2007     createUnwindExceptionTest(*module,
   2008                               theBuilder,
   2009                               fpm,
   2010                               "throwCppException");
   2011 
   2012     executionEngine->finalizeObject();
   2013 
   2014     fprintf(stderr, "\nBegin module dump:\n\n");
   2015 
   2016     module->dump();
   2017 
   2018     fprintf(stderr, "\nEnd module dump:\n");
   2019 
   2020     fprintf(stderr, "\n\nBegin Test:\n");
   2021 
   2022     for (int i = 1; i < argc; ++i) {
   2023       // Run test for each argument whose value is the exception
   2024       // type to throw.
   2025       runExceptionThrow(executionEngine,
   2026                         toRun,
   2027                         (unsigned) strtoul(argv[i], NULL, 10));
   2028     }
   2029 
   2030     fprintf(stderr, "\nEnd Test:\n\n");
   2031   }
   2032 
   2033   delete executionEngine;
   2034 
   2035   return 0;
   2036 }
   2037