Home | History | Annotate | Download | only in ExceptionDemo
      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/Analysis/Verifier.h"
     52 #include "llvm/ExecutionEngine/MCJIT.h"
     53 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
     54 #include "llvm/IR/DataLayout.h"
     55 #include "llvm/IR/DerivedTypes.h"
     56 #include "llvm/IR/IRBuilder.h"
     57 #include "llvm/IR/Intrinsics.h"
     58 #include "llvm/IR/LLVMContext.h"
     59 #include "llvm/IR/Module.h"
     60 #include "llvm/PassManager.h"
     61 #include "llvm/Support/Dwarf.h"
     62 #include "llvm/Support/TargetSelect.h"
     63 #include "llvm/Target/TargetOptions.h"
     64 #include "llvm/Transforms/Scalar.h"
     65 
     66 // FIXME: Although all systems tested with (Linux, OS X), do not need this
     67 //        header file included. A user on ubuntu reported, undefined symbols
     68 //        for stderr, and fprintf, and the addition of this include fixed the
     69 //        issue for them. Given that LLVM's best practices include the goal
     70 //        of reducing the number of redundant header files included, the
     71 //        correct solution would be to find out why these symbols are not
     72 //        defined for the system in question, and fix the issue by finding out
     73 //        which LLVM header file, if any, would include these symbols.
     74 #include <cstdio>
     75 
     76 #include <sstream>
     77 #include <stdexcept>
     78 
     79 
     80 #ifndef USE_GLOBAL_STR_CONSTS
     81 #define USE_GLOBAL_STR_CONSTS true
     82 #endif
     83 
     84 // System C++ ABI unwind types from:
     85 //     http://mentorembedded.github.com/cxx-abi/abi-eh.html (v1.22)
     86 
     87 extern "C" {
     88 
     89   typedef enum {
     90     _URC_NO_REASON = 0,
     91     _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
     92     _URC_FATAL_PHASE2_ERROR = 2,
     93     _URC_FATAL_PHASE1_ERROR = 3,
     94     _URC_NORMAL_STOP = 4,
     95     _URC_END_OF_STACK = 5,
     96     _URC_HANDLER_FOUND = 6,
     97     _URC_INSTALL_CONTEXT = 7,
     98     _URC_CONTINUE_UNWIND = 8
     99   } _Unwind_Reason_Code;
    100 
    101   typedef enum {
    102     _UA_SEARCH_PHASE = 1,
    103     _UA_CLEANUP_PHASE = 2,
    104     _UA_HANDLER_FRAME = 4,
    105     _UA_FORCE_UNWIND = 8,
    106     _UA_END_OF_STACK = 16
    107   } _Unwind_Action;
    108 
    109   struct _Unwind_Exception;
    110 
    111   typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
    112                                                 struct _Unwind_Exception *);
    113 
    114   struct _Unwind_Exception {
    115     uint64_t exception_class;
    116     _Unwind_Exception_Cleanup_Fn exception_cleanup;
    117 
    118     uintptr_t private_1;
    119     uintptr_t private_2;
    120 
    121     // @@@ The IA-64 ABI says that this structure must be double-word aligned.
    122     //  Taking that literally does not make much sense generically.  Instead
    123     //  we provide the maximum alignment required by any type for the machine.
    124   } __attribute__((__aligned__));
    125 
    126   struct _Unwind_Context;
    127   typedef struct _Unwind_Context *_Unwind_Context_t;
    128 
    129   extern const uint8_t *_Unwind_GetLanguageSpecificData (_Unwind_Context_t c);
    130   extern uintptr_t _Unwind_GetGR (_Unwind_Context_t c, int i);
    131   extern void _Unwind_SetGR (_Unwind_Context_t c, int i, uintptr_t n);
    132   extern void _Unwind_SetIP (_Unwind_Context_t, uintptr_t new_value);
    133   extern uintptr_t _Unwind_GetIP (_Unwind_Context_t context);
    134   extern uintptr_t _Unwind_GetRegionStart (_Unwind_Context_t context);
    135 
    136 } // extern "C"
    137 
    138 //
    139 // Example types
    140 //
    141 
    142 /// This is our simplistic type info
    143 struct OurExceptionType_t {
    144   /// type info type
    145   int type;
    146 };
    147 
    148 
    149 /// This is our Exception class which relies on a negative offset to calculate
    150 /// pointers to its instances from pointers to its unwindException member.
    151 ///
    152 /// Note: The above unwind.h defines struct _Unwind_Exception to be aligned
    153 ///       on a double word boundary. This is necessary to match the standard:
    154 ///       http://mentorembedded.github.com/cxx-abi/abi-eh.html
    155 struct OurBaseException_t {
    156   struct OurExceptionType_t type;
    157 
    158   // Note: This is properly aligned in unwind.h
    159   struct _Unwind_Exception unwindException;
    160 };
    161 
    162 
    163 // Note: Not needed since we are C++
    164 typedef struct OurBaseException_t OurException;
    165 typedef struct _Unwind_Exception OurUnwindException;
    166 
    167 //
    168 // Various globals used to support typeinfo and generatted exceptions in
    169 // general
    170 //
    171 
    172 static std::map<std::string, llvm::Value*> namedValues;
    173 
    174 int64_t ourBaseFromUnwindOffset;
    175 
    176 const unsigned char ourBaseExcpClassChars[] =
    177 {'o', 'b', 'j', '\0', 'b', 'a', 's', '\0'};
    178 
    179 
    180 static uint64_t ourBaseExceptionClass = 0;
    181 
    182 static std::vector<std::string> ourTypeInfoNames;
    183 static std::map<int, std::string> ourTypeInfoNamesIndex;
    184 
    185 static llvm::StructType *ourTypeInfoType;
    186 static llvm::StructType *ourCaughtResultType;
    187 static llvm::StructType *ourExceptionType;
    188 static llvm::StructType *ourUnwindExceptionType;
    189 
    190 static llvm::ConstantInt *ourExceptionNotThrownState;
    191 static llvm::ConstantInt *ourExceptionThrownState;
    192 static llvm::ConstantInt *ourExceptionCaughtState;
    193 
    194 typedef std::vector<std::string> ArgNames;
    195 typedef std::vector<llvm::Type*> ArgTypes;
    196 
    197 //
    198 // Code Generation Utilities
    199 //
    200 
    201 /// Utility used to create a function, both declarations and definitions
    202 /// @param module for module instance
    203 /// @param retType function return type
    204 /// @param theArgTypes function's ordered argument types
    205 /// @param theArgNames function's ordered arguments needed if use of this
    206 ///        function corresponds to a function definition. Use empty
    207 ///        aggregate for function declarations.
    208 /// @param functName function name
    209 /// @param linkage function linkage
    210 /// @param declarationOnly for function declarations
    211 /// @param isVarArg function uses vararg arguments
    212 /// @returns function instance
    213 llvm::Function *createFunction(llvm::Module &module,
    214                                llvm::Type *retType,
    215                                const ArgTypes &theArgTypes,
    216                                const ArgNames &theArgNames,
    217                                const std::string &functName,
    218                                llvm::GlobalValue::LinkageTypes linkage,
    219                                bool declarationOnly,
    220                                bool isVarArg) {
    221   llvm::FunctionType *functType =
    222     llvm::FunctionType::get(retType, theArgTypes, isVarArg);
    223   llvm::Function *ret =
    224     llvm::Function::Create(functType, linkage, functName, &module);
    225   if (!ret || declarationOnly)
    226     return(ret);
    227 
    228   namedValues.clear();
    229   unsigned i = 0;
    230   for (llvm::Function::arg_iterator argIndex = ret->arg_begin();
    231        i != theArgNames.size();
    232        ++argIndex, ++i) {
    233 
    234     argIndex->setName(theArgNames[i]);
    235     namedValues[theArgNames[i]] = argIndex;
    236   }
    237 
    238   return(ret);
    239 }
    240 
    241 
    242 /// Create an alloca instruction in the entry block of
    243 /// the parent function.  This is used for mutable variables etc.
    244 /// @param function parent instance
    245 /// @param varName stack variable name
    246 /// @param type stack variable type
    247 /// @param initWith optional constant initialization value
    248 /// @returns AllocaInst instance
    249 static llvm::AllocaInst *createEntryBlockAlloca(llvm::Function &function,
    250                                                 const std::string &varName,
    251                                                 llvm::Type *type,
    252                                                 llvm::Constant *initWith = 0) {
    253   llvm::BasicBlock &block = function.getEntryBlock();
    254   llvm::IRBuilder<> tmp(&block, block.begin());
    255   llvm::AllocaInst *ret = tmp.CreateAlloca(type, 0, varName.c_str());
    256 
    257   if (initWith)
    258     tmp.CreateStore(initWith, ret);
    259 
    260   return(ret);
    261 }
    262 
    263 
    264 //
    265 // Code Generation Utilities End
    266 //
    267 
    268 //
    269 // Runtime C Library functions
    270 //
    271 
    272 // Note: using an extern "C" block so that static functions can be used
    273 extern "C" {
    274 
    275 // Note: Better ways to decide on bit width
    276 //
    277 /// Prints a 32 bit number, according to the format, to stderr.
    278 /// @param intToPrint integer to print
    279 /// @param format printf like format to use when printing
    280 void print32Int(int intToPrint, const char *format) {
    281   if (format) {
    282     // Note: No NULL check
    283     fprintf(stderr, format, intToPrint);
    284   }
    285   else {
    286     // Note: No NULL check
    287     fprintf(stderr, "::print32Int(...):NULL arg.\n");
    288   }
    289 }
    290 
    291 
    292 // Note: Better ways to decide on bit width
    293 //
    294 /// Prints a 64 bit number, according to the format, to stderr.
    295 /// @param intToPrint integer to print
    296 /// @param format printf like format to use when printing
    297 void print64Int(long int intToPrint, const char *format) {
    298   if (format) {
    299     // Note: No NULL check
    300     fprintf(stderr, format, intToPrint);
    301   }
    302   else {
    303     // Note: No NULL check
    304     fprintf(stderr, "::print64Int(...):NULL arg.\n");
    305   }
    306 }
    307 
    308 
    309 /// Prints a C string to stderr
    310 /// @param toPrint string to print
    311 void printStr(char *toPrint) {
    312   if (toPrint) {
    313     fprintf(stderr, "%s", toPrint);
    314   }
    315   else {
    316     fprintf(stderr, "::printStr(...):NULL arg.\n");
    317   }
    318 }
    319 
    320 
    321 /// Deletes the true previosly allocated exception whose address
    322 /// is calculated from the supplied OurBaseException_t::unwindException
    323 /// member address. Handles (ignores), NULL pointers.
    324 /// @param expToDelete exception to delete
    325 void deleteOurException(OurUnwindException *expToDelete) {
    326 #ifdef DEBUG
    327   fprintf(stderr,
    328           "deleteOurException(...).\n");
    329 #endif
    330 
    331   if (expToDelete &&
    332       (expToDelete->exception_class == ourBaseExceptionClass)) {
    333 
    334     free(((char*) expToDelete) + ourBaseFromUnwindOffset);
    335   }
    336 }
    337 
    338 
    339 /// This function is the struct _Unwind_Exception API mandated delete function
    340 /// used by foreign exception handlers when deleting our exception
    341 /// (OurException), instances.
    342 /// @param reason See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html
    343 /// @unlink
    344 /// @param expToDelete exception instance to delete
    345 void deleteFromUnwindOurException(_Unwind_Reason_Code reason,
    346                                   OurUnwindException *expToDelete) {
    347 #ifdef DEBUG
    348   fprintf(stderr,
    349           "deleteFromUnwindOurException(...).\n");
    350 #endif
    351 
    352   deleteOurException(expToDelete);
    353 }
    354 
    355 
    356 /// Creates (allocates on the heap), an exception (OurException instance),
    357 /// of the supplied type info type.
    358 /// @param type type info type
    359 OurUnwindException *createOurException(int type) {
    360   size_t size = sizeof(OurException);
    361   OurException *ret = (OurException*) memset(malloc(size), 0, size);
    362   (ret->type).type = type;
    363   (ret->unwindException).exception_class = ourBaseExceptionClass;
    364   (ret->unwindException).exception_cleanup = deleteFromUnwindOurException;
    365 
    366   return(&(ret->unwindException));
    367 }
    368 
    369 
    370 /// Read a uleb128 encoded value and advance pointer
    371 /// See Variable Length Data in:
    372 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    373 /// @param data reference variable holding memory pointer to decode from
    374 /// @returns decoded value
    375 static uintptr_t readULEB128(const uint8_t **data) {
    376   uintptr_t result = 0;
    377   uintptr_t shift = 0;
    378   unsigned char byte;
    379   const uint8_t *p = *data;
    380 
    381   do {
    382     byte = *p++;
    383     result |= (byte & 0x7f) << shift;
    384     shift += 7;
    385   }
    386   while (byte & 0x80);
    387 
    388   *data = p;
    389 
    390   return result;
    391 }
    392 
    393 
    394 /// Read a sleb128 encoded value and advance pointer
    395 /// See Variable Length Data in:
    396 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    397 /// @param data reference variable holding memory pointer to decode from
    398 /// @returns decoded value
    399 static uintptr_t readSLEB128(const uint8_t **data) {
    400   uintptr_t result = 0;
    401   uintptr_t shift = 0;
    402   unsigned char byte;
    403   const uint8_t *p = *data;
    404 
    405   do {
    406     byte = *p++;
    407     result |= (byte & 0x7f) << shift;
    408     shift += 7;
    409   }
    410   while (byte & 0x80);
    411 
    412   *data = p;
    413 
    414   if ((byte & 0x40) && (shift < (sizeof(result) << 3))) {
    415     result |= (~0 << shift);
    416   }
    417 
    418   return result;
    419 }
    420 
    421 unsigned getEncodingSize(uint8_t Encoding) {
    422   if (Encoding == llvm::dwarf::DW_EH_PE_omit)
    423     return 0;
    424 
    425   switch (Encoding & 0x0F) {
    426   case llvm::dwarf::DW_EH_PE_absptr:
    427     return sizeof(uintptr_t);
    428   case llvm::dwarf::DW_EH_PE_udata2:
    429     return sizeof(uint16_t);
    430   case llvm::dwarf::DW_EH_PE_udata4:
    431     return sizeof(uint32_t);
    432   case llvm::dwarf::DW_EH_PE_udata8:
    433     return sizeof(uint64_t);
    434   case llvm::dwarf::DW_EH_PE_sdata2:
    435     return sizeof(int16_t);
    436   case llvm::dwarf::DW_EH_PE_sdata4:
    437     return sizeof(int32_t);
    438   case llvm::dwarf::DW_EH_PE_sdata8:
    439     return sizeof(int64_t);
    440   default:
    441     // not supported
    442     abort();
    443   }
    444 }
    445 
    446 /// Read a pointer encoded value and advance pointer
    447 /// See Variable Length Data in:
    448 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    449 /// @param data reference variable holding memory pointer to decode from
    450 /// @param encoding dwarf encoding type
    451 /// @returns decoded value
    452 static uintptr_t readEncodedPointer(const uint8_t **data, uint8_t encoding) {
    453   uintptr_t result = 0;
    454   const uint8_t *p = *data;
    455 
    456   if (encoding == llvm::dwarf::DW_EH_PE_omit)
    457     return(result);
    458 
    459   // first get value
    460   switch (encoding & 0x0F) {
    461     case llvm::dwarf::DW_EH_PE_absptr:
    462       result = *((uintptr_t*)p);
    463       p += sizeof(uintptr_t);
    464       break;
    465     case llvm::dwarf::DW_EH_PE_uleb128:
    466       result = readULEB128(&p);
    467       break;
    468       // Note: This case has not been tested
    469     case llvm::dwarf::DW_EH_PE_sleb128:
    470       result = readSLEB128(&p);
    471       break;
    472     case llvm::dwarf::DW_EH_PE_udata2:
    473       result = *((uint16_t*)p);
    474       p += sizeof(uint16_t);
    475       break;
    476     case llvm::dwarf::DW_EH_PE_udata4:
    477       result = *((uint32_t*)p);
    478       p += sizeof(uint32_t);
    479       break;
    480     case llvm::dwarf::DW_EH_PE_udata8:
    481       result = *((uint64_t*)p);
    482       p += sizeof(uint64_t);
    483       break;
    484     case llvm::dwarf::DW_EH_PE_sdata2:
    485       result = *((int16_t*)p);
    486       p += sizeof(int16_t);
    487       break;
    488     case llvm::dwarf::DW_EH_PE_sdata4:
    489       result = *((int32_t*)p);
    490       p += sizeof(int32_t);
    491       break;
    492     case llvm::dwarf::DW_EH_PE_sdata8:
    493       result = *((int64_t*)p);
    494       p += sizeof(int64_t);
    495       break;
    496     default:
    497       // not supported
    498       abort();
    499       break;
    500   }
    501 
    502   // then add relative offset
    503   switch (encoding & 0x70) {
    504     case llvm::dwarf::DW_EH_PE_absptr:
    505       // do nothing
    506       break;
    507     case llvm::dwarf::DW_EH_PE_pcrel:
    508       result += (uintptr_t)(*data);
    509       break;
    510     case llvm::dwarf::DW_EH_PE_textrel:
    511     case llvm::dwarf::DW_EH_PE_datarel:
    512     case llvm::dwarf::DW_EH_PE_funcrel:
    513     case llvm::dwarf::DW_EH_PE_aligned:
    514     default:
    515       // not supported
    516       abort();
    517       break;
    518   }
    519 
    520   // then apply indirection
    521   if (encoding & llvm::dwarf::DW_EH_PE_indirect) {
    522     result = *((uintptr_t*)result);
    523   }
    524 
    525   *data = p;
    526 
    527   return result;
    528 }
    529 
    530 
    531 /// Deals with Dwarf actions matching our type infos
    532 /// (OurExceptionType_t instances). Returns whether or not a dwarf emitted
    533 /// action matches the supplied exception type. If such a match succeeds,
    534 /// the resultAction argument will be set with > 0 index value. Only
    535 /// corresponding llvm.eh.selector type info arguments, cleanup arguments
    536 /// are supported. Filters are not supported.
    537 /// See Variable Length Data in:
    538 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
    539 /// Also see @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    540 /// @param resultAction reference variable which will be set with result
    541 /// @param classInfo our array of type info pointers (to globals)
    542 /// @param actionEntry index into above type info array or 0 (clean up).
    543 ///        We do not support filters.
    544 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    545 ///        of thrown exception.
    546 /// @param exceptionObject thrown _Unwind_Exception instance.
    547 /// @returns whether or not a type info was found. False is returned if only
    548 ///          a cleanup was found
    549 static bool handleActionValue(int64_t *resultAction,
    550                               uint8_t TTypeEncoding,
    551                               const uint8_t *ClassInfo,
    552                               uintptr_t actionEntry,
    553                               uint64_t exceptionClass,
    554                               struct _Unwind_Exception *exceptionObject) {
    555   bool ret = false;
    556 
    557   if (!resultAction ||
    558       !exceptionObject ||
    559       (exceptionClass != ourBaseExceptionClass))
    560     return(ret);
    561 
    562   struct OurBaseException_t *excp = (struct OurBaseException_t*)
    563   (((char*) exceptionObject) + ourBaseFromUnwindOffset);
    564   struct OurExceptionType_t *excpType = &(excp->type);
    565   int type = excpType->type;
    566 
    567 #ifdef DEBUG
    568   fprintf(stderr,
    569           "handleActionValue(...): exceptionObject = <%p>, "
    570           "excp = <%p>.\n",
    571           exceptionObject,
    572           excp);
    573 #endif
    574 
    575   const uint8_t *actionPos = (uint8_t*) actionEntry,
    576   *tempActionPos;
    577   int64_t typeOffset = 0,
    578   actionOffset;
    579 
    580   for (int i = 0; true; ++i) {
    581     // Each emitted dwarf action corresponds to a 2 tuple of
    582     // type info address offset, and action offset to the next
    583     // emitted action.
    584     typeOffset = readSLEB128(&actionPos);
    585     tempActionPos = actionPos;
    586     actionOffset = readSLEB128(&tempActionPos);
    587 
    588 #ifdef DEBUG
    589     fprintf(stderr,
    590             "handleActionValue(...):typeOffset: <%lld>, "
    591             "actionOffset: <%lld>.\n",
    592             typeOffset,
    593             actionOffset);
    594 #endif
    595     assert((typeOffset >= 0) &&
    596            "handleActionValue(...):filters are not supported.");
    597 
    598     // Note: A typeOffset == 0 implies that a cleanup llvm.eh.selector
    599     //       argument has been matched.
    600     if (typeOffset > 0) {
    601 #ifdef DEBUG
    602       fprintf(stderr,
    603               "handleActionValue(...):actionValue <%d> found.\n",
    604               i);
    605 #endif
    606       unsigned EncSize = getEncodingSize(TTypeEncoding);
    607       const uint8_t *EntryP = ClassInfo - typeOffset * EncSize;
    608       uintptr_t P = readEncodedPointer(&EntryP, TTypeEncoding);
    609       struct OurExceptionType_t *ThisClassInfo =
    610         reinterpret_cast<struct OurExceptionType_t *>(P);
    611       if (ThisClassInfo->type == type) {
    612         *resultAction = i + 1;
    613         ret = true;
    614         break;
    615       }
    616     }
    617 
    618 #ifdef DEBUG
    619     fprintf(stderr,
    620             "handleActionValue(...):actionValue not found.\n");
    621 #endif
    622     if (!actionOffset)
    623       break;
    624 
    625     actionPos += actionOffset;
    626   }
    627 
    628   return(ret);
    629 }
    630 
    631 
    632 /// Deals with the Language specific data portion of the emitted dwarf code.
    633 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    634 /// @param version unsupported (ignored), unwind version
    635 /// @param lsda language specific data area
    636 /// @param _Unwind_Action actions minimally supported unwind stage
    637 ///        (forced specifically not supported)
    638 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    639 ///        of thrown exception.
    640 /// @param exceptionObject thrown _Unwind_Exception instance.
    641 /// @param context unwind system context
    642 /// @returns minimally supported unwinding control indicator
    643 static _Unwind_Reason_Code handleLsda(int version,
    644                                       const uint8_t *lsda,
    645                                       _Unwind_Action actions,
    646                                       uint64_t exceptionClass,
    647                                     struct _Unwind_Exception *exceptionObject,
    648                                       _Unwind_Context_t context) {
    649   _Unwind_Reason_Code ret = _URC_CONTINUE_UNWIND;
    650 
    651   if (!lsda)
    652     return(ret);
    653 
    654 #ifdef DEBUG
    655   fprintf(stderr,
    656           "handleLsda(...):lsda is non-zero.\n");
    657 #endif
    658 
    659   // Get the current instruction pointer and offset it before next
    660   // instruction in the current frame which threw the exception.
    661   uintptr_t pc = _Unwind_GetIP(context)-1;
    662 
    663   // Get beginning current frame's code (as defined by the
    664   // emitted dwarf code)
    665   uintptr_t funcStart = _Unwind_GetRegionStart(context);
    666   uintptr_t pcOffset = pc - funcStart;
    667   const uint8_t *ClassInfo = NULL;
    668 
    669   // Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding
    670   //       dwarf emission
    671 
    672   // Parse LSDA header.
    673   uint8_t lpStartEncoding = *lsda++;
    674 
    675   if (lpStartEncoding != llvm::dwarf::DW_EH_PE_omit) {
    676     readEncodedPointer(&lsda, lpStartEncoding);
    677   }
    678 
    679   uint8_t ttypeEncoding = *lsda++;
    680   uintptr_t classInfoOffset;
    681 
    682   if (ttypeEncoding != llvm::dwarf::DW_EH_PE_omit) {
    683     // Calculate type info locations in emitted dwarf code which
    684     // were flagged by type info arguments to llvm.eh.selector
    685     // intrinsic
    686     classInfoOffset = readULEB128(&lsda);
    687     ClassInfo = lsda + classInfoOffset;
    688   }
    689 
    690   // Walk call-site table looking for range that
    691   // includes current PC.
    692 
    693   uint8_t         callSiteEncoding = *lsda++;
    694   uint32_t        callSiteTableLength = readULEB128(&lsda);
    695   const uint8_t   *callSiteTableStart = lsda;
    696   const uint8_t   *callSiteTableEnd = callSiteTableStart +
    697   callSiteTableLength;
    698   const uint8_t   *actionTableStart = callSiteTableEnd;
    699   const uint8_t   *callSitePtr = callSiteTableStart;
    700 
    701   while (callSitePtr < callSiteTableEnd) {
    702     uintptr_t start = readEncodedPointer(&callSitePtr,
    703                                          callSiteEncoding);
    704     uintptr_t length = readEncodedPointer(&callSitePtr,
    705                                           callSiteEncoding);
    706     uintptr_t landingPad = readEncodedPointer(&callSitePtr,
    707                                               callSiteEncoding);
    708 
    709     // Note: Action value
    710     uintptr_t actionEntry = readULEB128(&callSitePtr);
    711 
    712     if (exceptionClass != ourBaseExceptionClass) {
    713       // We have been notified of a foreign exception being thrown,
    714       // and we therefore need to execute cleanup landing pads
    715       actionEntry = 0;
    716     }
    717 
    718     if (landingPad == 0) {
    719 #ifdef DEBUG
    720       fprintf(stderr,
    721               "handleLsda(...): No landing pad found.\n");
    722 #endif
    723 
    724       continue; // no landing pad for this entry
    725     }
    726 
    727     if (actionEntry) {
    728       actionEntry += ((uintptr_t) actionTableStart) - 1;
    729     }
    730     else {
    731 #ifdef DEBUG
    732       fprintf(stderr,
    733               "handleLsda(...):No action table found.\n");
    734 #endif
    735     }
    736 
    737     bool exceptionMatched = false;
    738 
    739     if ((start <= pcOffset) && (pcOffset < (start + length))) {
    740 #ifdef DEBUG
    741       fprintf(stderr,
    742               "handleLsda(...): Landing pad found.\n");
    743 #endif
    744       int64_t actionValue = 0;
    745 
    746       if (actionEntry) {
    747         exceptionMatched = handleActionValue(&actionValue,
    748                                              ttypeEncoding,
    749                                              ClassInfo,
    750                                              actionEntry,
    751                                              exceptionClass,
    752                                              exceptionObject);
    753       }
    754 
    755       if (!(actions & _UA_SEARCH_PHASE)) {
    756 #ifdef DEBUG
    757         fprintf(stderr,
    758                 "handleLsda(...): installed landing pad "
    759                 "context.\n");
    760 #endif
    761 
    762         // Found landing pad for the PC.
    763         // Set Instruction Pointer to so we re-enter function
    764         // at landing pad. The landing pad is created by the
    765         // compiler to take two parameters in registers.
    766         _Unwind_SetGR(context,
    767                       __builtin_eh_return_data_regno(0),
    768                       (uintptr_t)exceptionObject);
    769 
    770         // Note: this virtual register directly corresponds
    771         //       to the return of the llvm.eh.selector intrinsic
    772         if (!actionEntry || !exceptionMatched) {
    773           // We indicate cleanup only
    774           _Unwind_SetGR(context,
    775                         __builtin_eh_return_data_regno(1),
    776                         0);
    777         }
    778         else {
    779           // Matched type info index of llvm.eh.selector intrinsic
    780           // passed here.
    781           _Unwind_SetGR(context,
    782                         __builtin_eh_return_data_regno(1),
    783                         actionValue);
    784         }
    785 
    786         // To execute landing pad set here
    787         _Unwind_SetIP(context, funcStart + landingPad);
    788         ret = _URC_INSTALL_CONTEXT;
    789       }
    790       else if (exceptionMatched) {
    791 #ifdef DEBUG
    792         fprintf(stderr,
    793                 "handleLsda(...): setting handler found.\n");
    794 #endif
    795         ret = _URC_HANDLER_FOUND;
    796       }
    797       else {
    798         // Note: Only non-clean up handlers are marked as
    799         //       found. Otherwise the clean up handlers will be
    800         //       re-found and executed during the clean up
    801         //       phase.
    802 #ifdef DEBUG
    803         fprintf(stderr,
    804                 "handleLsda(...): cleanup handler found.\n");
    805 #endif
    806       }
    807 
    808       break;
    809     }
    810   }
    811 
    812   return(ret);
    813 }
    814 
    815 
    816 /// This is the personality function which is embedded (dwarf emitted), in the
    817 /// dwarf unwind info block. Again see: JITDwarfEmitter.cpp.
    818 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    819 /// @param version unsupported (ignored), unwind version
    820 /// @param _Unwind_Action actions minimally supported unwind stage
    821 ///        (forced specifically not supported)
    822 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
    823 ///        of thrown exception.
    824 /// @param exceptionObject thrown _Unwind_Exception instance.
    825 /// @param context unwind system context
    826 /// @returns minimally supported unwinding control indicator
    827 _Unwind_Reason_Code ourPersonality(int version,
    828                                    _Unwind_Action actions,
    829                                    uint64_t exceptionClass,
    830                                    struct _Unwind_Exception *exceptionObject,
    831                                    _Unwind_Context_t context) {
    832 #ifdef DEBUG
    833   fprintf(stderr,
    834           "We are in ourPersonality(...):actions is <%d>.\n",
    835           actions);
    836 
    837   if (actions & _UA_SEARCH_PHASE) {
    838     fprintf(stderr, "ourPersonality(...):In search phase.\n");
    839   }
    840   else {
    841     fprintf(stderr, "ourPersonality(...):In non-search phase.\n");
    842   }
    843 #endif
    844 
    845   const uint8_t *lsda = _Unwind_GetLanguageSpecificData(context);
    846 
    847 #ifdef DEBUG
    848   fprintf(stderr,
    849           "ourPersonality(...):lsda = <%p>.\n",
    850           lsda);
    851 #endif
    852 
    853   // The real work of the personality function is captured here
    854   return(handleLsda(version,
    855                     lsda,
    856                     actions,
    857                     exceptionClass,
    858                     exceptionObject,
    859                     context));
    860 }
    861 
    862 
    863 /// Generates our _Unwind_Exception class from a given character array.
    864 /// thereby handling arbitrary lengths (not in standard), and handling
    865 /// embedded \0s.
    866 /// See @link http://mentorembedded.github.com/cxx-abi/abi-eh.html @unlink
    867 /// @param classChars char array to encode. NULL values not checkedf
    868 /// @param classCharsSize number of chars in classChars. Value is not checked.
    869 /// @returns class value
    870 uint64_t genClass(const unsigned char classChars[], size_t classCharsSize)
    871 {
    872   uint64_t ret = classChars[0];
    873 
    874   for (unsigned i = 1; i < classCharsSize; ++i) {
    875     ret <<= 8;
    876     ret += classChars[i];
    877   }
    878 
    879   return(ret);
    880 }
    881 
    882 } // extern "C"
    883 
    884 //
    885 // Runtime C Library functions End
    886 //
    887 
    888 //
    889 // Code generation functions
    890 //
    891 
    892 /// Generates code to print given constant string
    893 /// @param context llvm context
    894 /// @param module code for module instance
    895 /// @param builder builder instance
    896 /// @param toPrint string to print
    897 /// @param useGlobal A value of true (default) indicates a GlobalValue is
    898 ///        generated, and is used to hold the constant string. A value of
    899 ///        false indicates that the constant string will be stored on the
    900 ///        stack.
    901 void generateStringPrint(llvm::LLVMContext &context,
    902                          llvm::Module &module,
    903                          llvm::IRBuilder<> &builder,
    904                          std::string toPrint,
    905                          bool useGlobal = true) {
    906   llvm::Function *printFunct = module.getFunction("printStr");
    907 
    908   llvm::Value *stringVar;
    909   llvm::Constant *stringConstant =
    910   llvm::ConstantDataArray::getString(context, toPrint);
    911 
    912   if (useGlobal) {
    913     // Note: Does not work without allocation
    914     stringVar =
    915     new llvm::GlobalVariable(module,
    916                              stringConstant->getType(),
    917                              true,
    918                              llvm::GlobalValue::LinkerPrivateLinkage,
    919                              stringConstant,
    920                              "");
    921   }
    922   else {
    923     stringVar = builder.CreateAlloca(stringConstant->getType());
    924     builder.CreateStore(stringConstant, stringVar);
    925   }
    926 
    927   llvm::Value *cast = builder.CreatePointerCast(stringVar,
    928                                                 builder.getInt8PtrTy());
    929   builder.CreateCall(printFunct, cast);
    930 }
    931 
    932 
    933 /// Generates code to print given runtime integer according to constant
    934 /// string format, and a given print function.
    935 /// @param context llvm context
    936 /// @param module code for module instance
    937 /// @param builder builder instance
    938 /// @param printFunct function used to "print" integer
    939 /// @param toPrint string to print
    940 /// @param format printf like formating string for print
    941 /// @param useGlobal A value of true (default) indicates a GlobalValue is
    942 ///        generated, and is used to hold the constant string. A value of
    943 ///        false indicates that the constant string will be stored on the
    944 ///        stack.
    945 void generateIntegerPrint(llvm::LLVMContext &context,
    946                           llvm::Module &module,
    947                           llvm::IRBuilder<> &builder,
    948                           llvm::Function &printFunct,
    949                           llvm::Value &toPrint,
    950                           std::string format,
    951                           bool useGlobal = true) {
    952   llvm::Constant *stringConstant =
    953     llvm::ConstantDataArray::getString(context, format);
    954   llvm::Value *stringVar;
    955 
    956   if (useGlobal) {
    957     // Note: Does not seem to work without allocation
    958     stringVar =
    959     new llvm::GlobalVariable(module,
    960                              stringConstant->getType(),
    961                              true,
    962                              llvm::GlobalValue::LinkerPrivateLinkage,
    963                              stringConstant,
    964                              "");
    965   }
    966   else {
    967     stringVar = builder.CreateAlloca(stringConstant->getType());
    968     builder.CreateStore(stringConstant, stringVar);
    969   }
    970 
    971   llvm::Value *cast = builder.CreateBitCast(stringVar,
    972                                             builder.getInt8PtrTy());
    973   builder.CreateCall2(&printFunct, &toPrint, cast);
    974 }
    975 
    976 
    977 /// Generates code to handle finally block type semantics: always runs
    978 /// regardless of whether a thrown exception is passing through or the
    979 /// parent function is simply exiting. In addition to printing some state
    980 /// to stderr, this code will resume the exception handling--runs the
    981 /// unwind resume block, if the exception has not been previously caught
    982 /// by a catch clause, and will otherwise execute the end block (terminator
    983 /// block). In addition this function creates the corresponding function's
    984 /// stack storage for the exception pointer and catch flag status.
    985 /// @param context llvm context
    986 /// @param module code for module instance
    987 /// @param builder builder instance
    988 /// @param toAddTo parent function to add block to
    989 /// @param blockName block name of new "finally" block.
    990 /// @param functionId output id used for printing
    991 /// @param terminatorBlock terminator "end" block
    992 /// @param unwindResumeBlock unwind resume block
    993 /// @param exceptionCaughtFlag reference exception caught/thrown status storage
    994 /// @param exceptionStorage reference to exception pointer storage
    995 /// @param caughtResultStorage reference to landingpad result storage
    996 /// @returns newly created block
    997 static llvm::BasicBlock *createFinallyBlock(llvm::LLVMContext &context,
    998                                             llvm::Module &module,
    999                                             llvm::IRBuilder<> &builder,
   1000                                             llvm::Function &toAddTo,
   1001                                             std::string &blockName,
   1002                                             std::string &functionId,
   1003                                             llvm::BasicBlock &terminatorBlock,
   1004                                             llvm::BasicBlock &unwindResumeBlock,
   1005                                             llvm::Value **exceptionCaughtFlag,
   1006                                             llvm::Value **exceptionStorage,
   1007                                             llvm::Value **caughtResultStorage) {
   1008   assert(exceptionCaughtFlag &&
   1009          "ExceptionDemo::createFinallyBlock(...):exceptionCaughtFlag "
   1010          "is NULL");
   1011   assert(exceptionStorage &&
   1012          "ExceptionDemo::createFinallyBlock(...):exceptionStorage "
   1013          "is NULL");
   1014   assert(caughtResultStorage &&
   1015          "ExceptionDemo::createFinallyBlock(...):caughtResultStorage "
   1016          "is NULL");
   1017 
   1018   *exceptionCaughtFlag = createEntryBlockAlloca(toAddTo,
   1019                                          "exceptionCaught",
   1020                                          ourExceptionNotThrownState->getType(),
   1021                                          ourExceptionNotThrownState);
   1022 
   1023   llvm::PointerType *exceptionStorageType = builder.getInt8PtrTy();
   1024   *exceptionStorage = createEntryBlockAlloca(toAddTo,
   1025                                              "exceptionStorage",
   1026                                              exceptionStorageType,
   1027                                              llvm::ConstantPointerNull::get(
   1028                                                exceptionStorageType));
   1029   *caughtResultStorage = createEntryBlockAlloca(toAddTo,
   1030                                               "caughtResultStorage",
   1031                                               ourCaughtResultType,
   1032                                               llvm::ConstantAggregateZero::get(
   1033                                                 ourCaughtResultType));
   1034 
   1035   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
   1036                                                    blockName,
   1037                                                    &toAddTo);
   1038 
   1039   builder.SetInsertPoint(ret);
   1040 
   1041   std::ostringstream bufferToPrint;
   1042   bufferToPrint << "Gen: Executing finally block "
   1043     << blockName << " in " << functionId << "\n";
   1044   generateStringPrint(context,
   1045                       module,
   1046                       builder,
   1047                       bufferToPrint.str(),
   1048                       USE_GLOBAL_STR_CONSTS);
   1049 
   1050   llvm::SwitchInst *theSwitch = builder.CreateSwitch(builder.CreateLoad(
   1051                                                        *exceptionCaughtFlag),
   1052                                                      &terminatorBlock,
   1053                                                      2);
   1054   theSwitch->addCase(ourExceptionCaughtState, &terminatorBlock);
   1055   theSwitch->addCase(ourExceptionThrownState, &unwindResumeBlock);
   1056 
   1057   return(ret);
   1058 }
   1059 
   1060 
   1061 /// Generates catch block semantics which print a string to indicate type of
   1062 /// catch executed, sets an exception caught flag, and executes passed in
   1063 /// end block (terminator block).
   1064 /// @param context llvm context
   1065 /// @param module code for module instance
   1066 /// @param builder builder instance
   1067 /// @param toAddTo parent function to add block to
   1068 /// @param blockName block name of new "catch" block.
   1069 /// @param functionId output id used for printing
   1070 /// @param terminatorBlock terminator "end" block
   1071 /// @param exceptionCaughtFlag exception caught/thrown status
   1072 /// @returns newly created block
   1073 static llvm::BasicBlock *createCatchBlock(llvm::LLVMContext &context,
   1074                                           llvm::Module &module,
   1075                                           llvm::IRBuilder<> &builder,
   1076                                           llvm::Function &toAddTo,
   1077                                           std::string &blockName,
   1078                                           std::string &functionId,
   1079                                           llvm::BasicBlock &terminatorBlock,
   1080                                           llvm::Value &exceptionCaughtFlag) {
   1081 
   1082   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
   1083                                                    blockName,
   1084                                                    &toAddTo);
   1085 
   1086   builder.SetInsertPoint(ret);
   1087 
   1088   std::ostringstream bufferToPrint;
   1089   bufferToPrint << "Gen: Executing catch block "
   1090   << blockName
   1091   << " in "
   1092   << functionId
   1093   << std::endl;
   1094   generateStringPrint(context,
   1095                       module,
   1096                       builder,
   1097                       bufferToPrint.str(),
   1098                       USE_GLOBAL_STR_CONSTS);
   1099   builder.CreateStore(ourExceptionCaughtState, &exceptionCaughtFlag);
   1100   builder.CreateBr(&terminatorBlock);
   1101 
   1102   return(ret);
   1103 }
   1104 
   1105 
   1106 /// Generates a function which invokes a function (toInvoke) and, whose
   1107 /// unwind block will "catch" the type info types correspondingly held in the
   1108 /// exceptionTypesToCatch argument. If the toInvoke function throws an
   1109 /// exception which does not match any type info types contained in
   1110 /// exceptionTypesToCatch, the generated code will call _Unwind_Resume
   1111 /// with the raised exception. On the other hand the generated code will
   1112 /// normally exit if the toInvoke function does not throw an exception.
   1113 /// The generated "finally" block is always run regardless of the cause of
   1114 /// the generated function exit.
   1115 /// The generated function is returned after being verified.
   1116 /// @param module code for module instance
   1117 /// @param builder builder instance
   1118 /// @param fpm a function pass manager holding optional IR to IR
   1119 ///        transformations
   1120 /// @param toInvoke inner function to invoke
   1121 /// @param ourId id used to printing purposes
   1122 /// @param numExceptionsToCatch length of exceptionTypesToCatch array
   1123 /// @param exceptionTypesToCatch array of type info types to "catch"
   1124 /// @returns generated function
   1125 static
   1126 llvm::Function *createCatchWrappedInvokeFunction(llvm::Module &module,
   1127                                              llvm::IRBuilder<> &builder,
   1128                                              llvm::FunctionPassManager &fpm,
   1129                                              llvm::Function &toInvoke,
   1130                                              std::string ourId,
   1131                                              unsigned numExceptionsToCatch,
   1132                                              unsigned exceptionTypesToCatch[]) {
   1133 
   1134   llvm::LLVMContext &context = module.getContext();
   1135   llvm::Function *toPrint32Int = module.getFunction("print32Int");
   1136 
   1137   ArgTypes argTypes;
   1138   argTypes.push_back(builder.getInt32Ty());
   1139 
   1140   ArgNames argNames;
   1141   argNames.push_back("exceptTypeToThrow");
   1142 
   1143   llvm::Function *ret = createFunction(module,
   1144                                        builder.getVoidTy(),
   1145                                        argTypes,
   1146                                        argNames,
   1147                                        ourId,
   1148                                        llvm::Function::ExternalLinkage,
   1149                                        false,
   1150                                        false);
   1151 
   1152   // Block which calls invoke
   1153   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
   1154                                                           "entry",
   1155                                                           ret);
   1156   // Normal block for invoke
   1157   llvm::BasicBlock *normalBlock = llvm::BasicBlock::Create(context,
   1158                                                            "normal",
   1159                                                            ret);
   1160   // Unwind block for invoke
   1161   llvm::BasicBlock *exceptionBlock = llvm::BasicBlock::Create(context,
   1162                                                               "exception",
   1163                                                               ret);
   1164 
   1165   // Block which routes exception to correct catch handler block
   1166   llvm::BasicBlock *exceptionRouteBlock = llvm::BasicBlock::Create(context,
   1167                                                              "exceptionRoute",
   1168                                                              ret);
   1169 
   1170   // Foreign exception handler
   1171   llvm::BasicBlock *externalExceptionBlock = llvm::BasicBlock::Create(context,
   1172                                                           "externalException",
   1173                                                           ret);
   1174 
   1175   // Block which calls _Unwind_Resume
   1176   llvm::BasicBlock *unwindResumeBlock = llvm::BasicBlock::Create(context,
   1177                                                                "unwindResume",
   1178                                                                ret);
   1179 
   1180   // Clean up block which delete exception if needed
   1181   llvm::BasicBlock *endBlock = llvm::BasicBlock::Create(context, "end", ret);
   1182 
   1183   std::string nextName;
   1184   std::vector<llvm::BasicBlock*> catchBlocks(numExceptionsToCatch);
   1185   llvm::Value *exceptionCaughtFlag = NULL;
   1186   llvm::Value *exceptionStorage = NULL;
   1187   llvm::Value *caughtResultStorage = NULL;
   1188 
   1189   // Finally block which will branch to unwindResumeBlock if
   1190   // exception is not caught. Initializes/allocates stack locations.
   1191   llvm::BasicBlock *finallyBlock = createFinallyBlock(context,
   1192                                                       module,
   1193                                                       builder,
   1194                                                       *ret,
   1195                                                       nextName = "finally",
   1196                                                       ourId,
   1197                                                       *endBlock,
   1198                                                       *unwindResumeBlock,
   1199                                                       &exceptionCaughtFlag,
   1200                                                       &exceptionStorage,
   1201                                                       &caughtResultStorage
   1202                                                       );
   1203 
   1204   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
   1205     nextName = ourTypeInfoNames[exceptionTypesToCatch[i]];
   1206 
   1207     // One catch block per type info to be caught
   1208     catchBlocks[i] = createCatchBlock(context,
   1209                                       module,
   1210                                       builder,
   1211                                       *ret,
   1212                                       nextName,
   1213                                       ourId,
   1214                                       *finallyBlock,
   1215                                       *exceptionCaughtFlag);
   1216   }
   1217 
   1218   // Entry Block
   1219 
   1220   builder.SetInsertPoint(entryBlock);
   1221 
   1222   std::vector<llvm::Value*> args;
   1223   args.push_back(namedValues["exceptTypeToThrow"]);
   1224   builder.CreateInvoke(&toInvoke,
   1225                        normalBlock,
   1226                        exceptionBlock,
   1227                        args);
   1228 
   1229   // End Block
   1230 
   1231   builder.SetInsertPoint(endBlock);
   1232 
   1233   generateStringPrint(context,
   1234                       module,
   1235                       builder,
   1236                       "Gen: In end block: exiting in " + ourId + ".\n",
   1237                       USE_GLOBAL_STR_CONSTS);
   1238   llvm::Function *deleteOurException = module.getFunction("deleteOurException");
   1239 
   1240   // Note: function handles NULL exceptions
   1241   builder.CreateCall(deleteOurException,
   1242                      builder.CreateLoad(exceptionStorage));
   1243   builder.CreateRetVoid();
   1244 
   1245   // Normal Block
   1246 
   1247   builder.SetInsertPoint(normalBlock);
   1248 
   1249   generateStringPrint(context,
   1250                       module,
   1251                       builder,
   1252                       "Gen: No exception in " + ourId + "!\n",
   1253                       USE_GLOBAL_STR_CONSTS);
   1254 
   1255   // Finally block is always called
   1256   builder.CreateBr(finallyBlock);
   1257 
   1258   // Unwind Resume Block
   1259 
   1260   builder.SetInsertPoint(unwindResumeBlock);
   1261 
   1262   builder.CreateResume(builder.CreateLoad(caughtResultStorage));
   1263 
   1264   // Exception Block
   1265 
   1266   builder.SetInsertPoint(exceptionBlock);
   1267 
   1268   llvm::Function *personality = module.getFunction("ourPersonality");
   1269 
   1270   llvm::LandingPadInst *caughtResult =
   1271     builder.CreateLandingPad(ourCaughtResultType,
   1272                              personality,
   1273                              numExceptionsToCatch,
   1274                              "landingPad");
   1275 
   1276   caughtResult->setCleanup(true);
   1277 
   1278   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
   1279     // Set up type infos to be caught
   1280     caughtResult->addClause(module.getGlobalVariable(
   1281                              ourTypeInfoNames[exceptionTypesToCatch[i]]));
   1282   }
   1283 
   1284   llvm::Value *unwindException = builder.CreateExtractValue(caughtResult, 0);
   1285   llvm::Value *retTypeInfoIndex = builder.CreateExtractValue(caughtResult, 1);
   1286 
   1287   // FIXME: Redundant storage which, beyond utilizing value of
   1288   //        caughtResultStore for unwindException storage, may be alleviated
   1289   //        altogether with a block rearrangement
   1290   builder.CreateStore(caughtResult, caughtResultStorage);
   1291   builder.CreateStore(unwindException, exceptionStorage);
   1292   builder.CreateStore(ourExceptionThrownState, exceptionCaughtFlag);
   1293 
   1294   // Retrieve exception_class member from thrown exception
   1295   // (_Unwind_Exception instance). This member tells us whether or not
   1296   // the exception is foreign.
   1297   llvm::Value *unwindExceptionClass =
   1298     builder.CreateLoad(builder.CreateStructGEP(
   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(typeInfoThrown, 0);
   1342 
   1343   llvm::Value *typeInfoThrownType =
   1344   builder.CreateStructGEP(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
   1393 llvm::Function *createThrowExceptionFunction(llvm::Module &module,
   1394                                              llvm::IRBuilder<> &builder,
   1395                                              llvm::FunctionPassManager &fpm,
   1396                                              std::string ourId,
   1397                                              int32_t nativeThrowType,
   1398                                              llvm::Function &nativeThrowFunct) {
   1399   llvm::LLVMContext &context = module.getContext();
   1400   namedValues.clear();
   1401   ArgTypes unwindArgTypes;
   1402   unwindArgTypes.push_back(builder.getInt32Ty());
   1403   ArgNames unwindArgNames;
   1404   unwindArgNames.push_back("exceptTypeToThrow");
   1405 
   1406   llvm::Function *ret = createFunction(module,
   1407                                        builder.getVoidTy(),
   1408                                        unwindArgTypes,
   1409                                        unwindArgNames,
   1410                                        ourId,
   1411                                        llvm::Function::ExternalLinkage,
   1412                                        false,
   1413                                        false);
   1414 
   1415   // Throws either one of our exception or a native C++ exception depending
   1416   // on a runtime argument value containing a type info type.
   1417   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
   1418                                                           "entry",
   1419                                                           ret);
   1420   // Throws a foreign exception
   1421   llvm::BasicBlock *nativeThrowBlock = llvm::BasicBlock::Create(context,
   1422                                                                 "nativeThrow",
   1423                                                                 ret);
   1424   // Throws one of our Exceptions
   1425   llvm::BasicBlock *generatedThrowBlock = llvm::BasicBlock::Create(context,
   1426                                                              "generatedThrow",
   1427                                                              ret);
   1428   // Retrieved runtime type info type to throw
   1429   llvm::Value *exceptionType = namedValues["exceptTypeToThrow"];
   1430 
   1431   // nativeThrowBlock block
   1432 
   1433   builder.SetInsertPoint(nativeThrowBlock);
   1434 
   1435   // Throws foreign exception
   1436   builder.CreateCall(&nativeThrowFunct, exceptionType);
   1437   builder.CreateUnreachable();
   1438 
   1439   // entry block
   1440 
   1441   builder.SetInsertPoint(entryBlock);
   1442 
   1443   llvm::Function *toPrint32Int = module.getFunction("print32Int");
   1444   generateIntegerPrint(context,
   1445                        module,
   1446                        builder,
   1447                        *toPrint32Int,
   1448                        *exceptionType,
   1449                        "\nGen: About to throw exception type <%d> in " +
   1450                        ourId +
   1451                        ".\n",
   1452                        USE_GLOBAL_STR_CONSTS);
   1453 
   1454   // Switches on runtime type info type value to determine whether or not
   1455   // a foreign exception is thrown. Defaults to throwing one of our
   1456   // generated exceptions.
   1457   llvm::SwitchInst *theSwitch = builder.CreateSwitch(exceptionType,
   1458                                                      generatedThrowBlock,
   1459                                                      1);
   1460 
   1461   theSwitch->addCase(llvm::ConstantInt::get(llvm::Type::getInt32Ty(context),
   1462                                             nativeThrowType),
   1463                      nativeThrowBlock);
   1464 
   1465   // generatedThrow block
   1466 
   1467   builder.SetInsertPoint(generatedThrowBlock);
   1468 
   1469   llvm::Function *createOurException = module.getFunction("createOurException");
   1470   llvm::Function *raiseOurException = module.getFunction(
   1471                                         "_Unwind_RaiseException");
   1472 
   1473   // Creates exception to throw with runtime type info type.
   1474   llvm::Value *exception = builder.CreateCall(createOurException,
   1475                                               namedValues["exceptTypeToThrow"]);
   1476 
   1477   // Throw generated Exception
   1478   builder.CreateCall(raiseOurException, exception);
   1479   builder.CreateUnreachable();
   1480 
   1481   llvm::verifyFunction(*ret);
   1482   fpm.run(*ret);
   1483 
   1484   return(ret);
   1485 }
   1486 
   1487 static void createStandardUtilityFunctions(unsigned numTypeInfos,
   1488                                            llvm::Module &module,
   1489                                            llvm::IRBuilder<> &builder);
   1490 
   1491 /// Creates test code by generating and organizing these functions into the
   1492 /// test case. The test case consists of an outer function setup to invoke
   1493 /// an inner function within an environment having multiple catch and single
   1494 /// finally blocks. This inner function is also setup to invoke a throw
   1495 /// function within an evironment similar in nature to the outer function's
   1496 /// catch and finally blocks. Each of these two functions catch mutually
   1497 /// exclusive subsets (even or odd) of the type info types configured
   1498 /// for this this. All generated functions have a runtime argument which
   1499 /// holds a type info type to throw that each function takes and passes it
   1500 /// to the inner one if such a inner function exists. This type info type is
   1501 /// looked at by the generated throw function to see whether or not it should
   1502 /// throw a generated exception with the same type info type, or instead call
   1503 /// a supplied a function which in turn will throw a foreign exception.
   1504 /// @param module code for module instance
   1505 /// @param builder builder instance
   1506 /// @param fpm a function pass manager holding optional IR to IR
   1507 ///        transformations
   1508 /// @param nativeThrowFunctName name of external function which will throw
   1509 ///        a foreign exception
   1510 /// @returns outermost generated test function.
   1511 llvm::Function *createUnwindExceptionTest(llvm::Module &module,
   1512                                           llvm::IRBuilder<> &builder,
   1513                                           llvm::FunctionPassManager &fpm,
   1514                                           std::string nativeThrowFunctName) {
   1515   // Number of type infos to generate
   1516   unsigned numTypeInfos = 6;
   1517 
   1518   // Initialze intrisics and external functions to use along with exception
   1519   // and type info globals.
   1520   createStandardUtilityFunctions(numTypeInfos,
   1521                                  module,
   1522                                  builder);
   1523   llvm::Function *nativeThrowFunct = module.getFunction(nativeThrowFunctName);
   1524 
   1525   // Create exception throw function using the value ~0 to cause
   1526   // foreign exceptions to be thrown.
   1527   llvm::Function *throwFunct = createThrowExceptionFunction(module,
   1528                                                             builder,
   1529                                                             fpm,
   1530                                                             "throwFunct",
   1531                                                             ~0,
   1532                                                             *nativeThrowFunct);
   1533   // Inner function will catch even type infos
   1534   unsigned innerExceptionTypesToCatch[] = {6, 2, 4};
   1535   size_t numExceptionTypesToCatch = sizeof(innerExceptionTypesToCatch) /
   1536                                     sizeof(unsigned);
   1537 
   1538   // Generate inner function.
   1539   llvm::Function *innerCatchFunct = createCatchWrappedInvokeFunction(module,
   1540                                                     builder,
   1541                                                     fpm,
   1542                                                     *throwFunct,
   1543                                                     "innerCatchFunct",
   1544                                                     numExceptionTypesToCatch,
   1545                                                     innerExceptionTypesToCatch);
   1546 
   1547   // Outer function will catch odd type infos
   1548   unsigned outerExceptionTypesToCatch[] = {3, 1, 5};
   1549   numExceptionTypesToCatch = sizeof(outerExceptionTypesToCatch) /
   1550   sizeof(unsigned);
   1551 
   1552   // Generate outer function
   1553   llvm::Function *outerCatchFunct = createCatchWrappedInvokeFunction(module,
   1554                                                     builder,
   1555                                                     fpm,
   1556                                                     *innerCatchFunct,
   1557                                                     "outerCatchFunct",
   1558                                                     numExceptionTypesToCatch,
   1559                                                     outerExceptionTypesToCatch);
   1560 
   1561   // Return outer function to run
   1562   return(outerCatchFunct);
   1563 }
   1564 
   1565 
   1566 /// Represents our foreign exceptions
   1567 class OurCppRunException : public std::runtime_error {
   1568 public:
   1569   OurCppRunException(const std::string reason) :
   1570   std::runtime_error(reason) {}
   1571 
   1572   OurCppRunException (const OurCppRunException &toCopy) :
   1573   std::runtime_error(toCopy) {}
   1574 
   1575   OurCppRunException &operator = (const OurCppRunException &toCopy) {
   1576     return(reinterpret_cast<OurCppRunException&>(
   1577                                  std::runtime_error::operator=(toCopy)));
   1578   }
   1579 
   1580   ~OurCppRunException (void) throw () {}
   1581 };
   1582 
   1583 
   1584 /// Throws foreign C++ exception.
   1585 /// @param ignoreIt unused parameter that allows function to match implied
   1586 ///        generated function contract.
   1587 extern "C"
   1588 void throwCppException (int32_t ignoreIt) {
   1589   throw(OurCppRunException("thrown by throwCppException(...)"));
   1590 }
   1591 
   1592 typedef void (*OurExceptionThrowFunctType) (int32_t typeToThrow);
   1593 
   1594 /// This is a test harness which runs test by executing generated
   1595 /// function with a type info type to throw. Harness wraps the execution
   1596 /// of generated function in a C++ try catch clause.
   1597 /// @param engine execution engine to use for executing generated function.
   1598 ///        This demo program expects this to be a JIT instance for demo
   1599 ///        purposes.
   1600 /// @param function generated test function to run
   1601 /// @param typeToThrow type info type of generated exception to throw, or
   1602 ///        indicator to cause foreign exception to be thrown.
   1603 static
   1604 void runExceptionThrow(llvm::ExecutionEngine *engine,
   1605                        llvm::Function *function,
   1606                        int32_t typeToThrow) {
   1607 
   1608   // Find test's function pointer
   1609   OurExceptionThrowFunctType functPtr =
   1610     reinterpret_cast<OurExceptionThrowFunctType>(
   1611        reinterpret_cast<intptr_t>(engine->getPointerToFunction(function)));
   1612 
   1613   try {
   1614     // Run test
   1615     (*functPtr)(typeToThrow);
   1616   }
   1617   catch (OurCppRunException exc) {
   1618     // Catch foreign C++ exception
   1619     fprintf(stderr,
   1620             "\nrunExceptionThrow(...):In C++ catch OurCppRunException "
   1621             "with reason: %s.\n",
   1622             exc.what());
   1623   }
   1624   catch (...) {
   1625     // Catch all exceptions including our generated ones. This latter
   1626     // functionality works according to the example in rules 1.6.4 of
   1627     // http://mentorembedded.github.com/cxx-abi/abi-eh.html (v1.22),
   1628     // given that these will be exceptions foreign to C++
   1629     // (the _Unwind_Exception::exception_class should be different from
   1630     // the one used by C++).
   1631     fprintf(stderr,
   1632             "\nrunExceptionThrow(...):In C++ catch all.\n");
   1633   }
   1634 }
   1635 
   1636 //
   1637 // End test functions
   1638 //
   1639 
   1640 typedef llvm::ArrayRef<llvm::Type*> TypeArray;
   1641 
   1642 /// This initialization routine creates type info globals and
   1643 /// adds external function declarations to module.
   1644 /// @param numTypeInfos number of linear type info associated type info types
   1645 ///        to create as GlobalVariable instances, starting with the value 1.
   1646 /// @param module code for module instance
   1647 /// @param builder builder instance
   1648 static void createStandardUtilityFunctions(unsigned numTypeInfos,
   1649                                            llvm::Module &module,
   1650                                            llvm::IRBuilder<> &builder) {
   1651 
   1652   llvm::LLVMContext &context = module.getContext();
   1653 
   1654   // Exception initializations
   1655 
   1656   // Setup exception catch state
   1657   ourExceptionNotThrownState =
   1658     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 0),
   1659   ourExceptionThrownState =
   1660     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 1),
   1661   ourExceptionCaughtState =
   1662     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 2),
   1663 
   1664 
   1665 
   1666   // Create our type info type
   1667   ourTypeInfoType = llvm::StructType::get(context,
   1668                                           TypeArray(builder.getInt32Ty()));
   1669 
   1670   llvm::Type *caughtResultFieldTypes[] = {
   1671     builder.getInt8PtrTy(),
   1672     builder.getInt32Ty()
   1673   };
   1674 
   1675   // Create our landingpad result type
   1676   ourCaughtResultType = llvm::StructType::get(context,
   1677                                             TypeArray(caughtResultFieldTypes));
   1678 
   1679   // Create OurException type
   1680   ourExceptionType = llvm::StructType::get(context,
   1681                                            TypeArray(ourTypeInfoType));
   1682 
   1683   // Create portion of _Unwind_Exception type
   1684   //
   1685   // Note: Declaring only a portion of the _Unwind_Exception struct.
   1686   //       Does this cause problems?
   1687   ourUnwindExceptionType =
   1688     llvm::StructType::get(context,
   1689                     TypeArray(builder.getInt64Ty()));
   1690 
   1691   struct OurBaseException_t dummyException;
   1692 
   1693   // Calculate offset of OurException::unwindException member.
   1694   ourBaseFromUnwindOffset = ((uintptr_t) &dummyException) -
   1695                             ((uintptr_t) &(dummyException.unwindException));
   1696 
   1697 #ifdef DEBUG
   1698   fprintf(stderr,
   1699           "createStandardUtilityFunctions(...):ourBaseFromUnwindOffset "
   1700           "= %lld, sizeof(struct OurBaseException_t) - "
   1701           "sizeof(struct _Unwind_Exception) = %lu.\n",
   1702           ourBaseFromUnwindOffset,
   1703           sizeof(struct OurBaseException_t) -
   1704           sizeof(struct _Unwind_Exception));
   1705 #endif
   1706 
   1707   size_t numChars = sizeof(ourBaseExcpClassChars) / sizeof(char);
   1708 
   1709   // Create our _Unwind_Exception::exception_class value
   1710   ourBaseExceptionClass = genClass(ourBaseExcpClassChars, numChars);
   1711 
   1712   // Type infos
   1713 
   1714   std::string baseStr = "typeInfo", typeInfoName;
   1715   std::ostringstream typeInfoNameBuilder;
   1716   std::vector<llvm::Constant*> structVals;
   1717 
   1718   llvm::Constant *nextStruct;
   1719 
   1720   // Generate each type info
   1721   //
   1722   // Note: First type info is not used.
   1723   for (unsigned i = 0; i <= numTypeInfos; ++i) {
   1724     structVals.clear();
   1725     structVals.push_back(llvm::ConstantInt::get(builder.getInt32Ty(), i));
   1726     nextStruct = llvm::ConstantStruct::get(ourTypeInfoType, structVals);
   1727 
   1728     typeInfoNameBuilder.str("");
   1729     typeInfoNameBuilder << baseStr << i;
   1730     typeInfoName = typeInfoNameBuilder.str();
   1731 
   1732     // Note: Does not seem to work without allocation
   1733     new llvm::GlobalVariable(module,
   1734                              ourTypeInfoType,
   1735                              true,
   1736                              llvm::GlobalValue::ExternalLinkage,
   1737                              nextStruct,
   1738                              typeInfoName);
   1739 
   1740     ourTypeInfoNames.push_back(typeInfoName);
   1741     ourTypeInfoNamesIndex[i] = typeInfoName;
   1742   }
   1743 
   1744   ArgNames argNames;
   1745   ArgTypes argTypes;
   1746   llvm::Function *funct = NULL;
   1747 
   1748   // print32Int
   1749 
   1750   llvm::Type *retType = builder.getVoidTy();
   1751 
   1752   argTypes.clear();
   1753   argTypes.push_back(builder.getInt32Ty());
   1754   argTypes.push_back(builder.getInt8PtrTy());
   1755 
   1756   argNames.clear();
   1757 
   1758   createFunction(module,
   1759                  retType,
   1760                  argTypes,
   1761                  argNames,
   1762                  "print32Int",
   1763                  llvm::Function::ExternalLinkage,
   1764                  true,
   1765                  false);
   1766 
   1767   // print64Int
   1768 
   1769   retType = builder.getVoidTy();
   1770 
   1771   argTypes.clear();
   1772   argTypes.push_back(builder.getInt64Ty());
   1773   argTypes.push_back(builder.getInt8PtrTy());
   1774 
   1775   argNames.clear();
   1776 
   1777   createFunction(module,
   1778                  retType,
   1779                  argTypes,
   1780                  argNames,
   1781                  "print64Int",
   1782                  llvm::Function::ExternalLinkage,
   1783                  true,
   1784                  false);
   1785 
   1786   // printStr
   1787 
   1788   retType = builder.getVoidTy();
   1789 
   1790   argTypes.clear();
   1791   argTypes.push_back(builder.getInt8PtrTy());
   1792 
   1793   argNames.clear();
   1794 
   1795   createFunction(module,
   1796                  retType,
   1797                  argTypes,
   1798                  argNames,
   1799                  "printStr",
   1800                  llvm::Function::ExternalLinkage,
   1801                  true,
   1802                  false);
   1803 
   1804   // throwCppException
   1805 
   1806   retType = builder.getVoidTy();
   1807 
   1808   argTypes.clear();
   1809   argTypes.push_back(builder.getInt32Ty());
   1810 
   1811   argNames.clear();
   1812 
   1813   createFunction(module,
   1814                  retType,
   1815                  argTypes,
   1816                  argNames,
   1817                  "throwCppException",
   1818                  llvm::Function::ExternalLinkage,
   1819                  true,
   1820                  false);
   1821 
   1822   // deleteOurException
   1823 
   1824   retType = builder.getVoidTy();
   1825 
   1826   argTypes.clear();
   1827   argTypes.push_back(builder.getInt8PtrTy());
   1828 
   1829   argNames.clear();
   1830 
   1831   createFunction(module,
   1832                  retType,
   1833                  argTypes,
   1834                  argNames,
   1835                  "deleteOurException",
   1836                  llvm::Function::ExternalLinkage,
   1837                  true,
   1838                  false);
   1839 
   1840   // createOurException
   1841 
   1842   retType = builder.getInt8PtrTy();
   1843 
   1844   argTypes.clear();
   1845   argTypes.push_back(builder.getInt32Ty());
   1846 
   1847   argNames.clear();
   1848 
   1849   createFunction(module,
   1850                  retType,
   1851                  argTypes,
   1852                  argNames,
   1853                  "createOurException",
   1854                  llvm::Function::ExternalLinkage,
   1855                  true,
   1856                  false);
   1857 
   1858   // _Unwind_RaiseException
   1859 
   1860   retType = builder.getInt32Ty();
   1861 
   1862   argTypes.clear();
   1863   argTypes.push_back(builder.getInt8PtrTy());
   1864 
   1865   argNames.clear();
   1866 
   1867   funct = createFunction(module,
   1868                          retType,
   1869                          argTypes,
   1870                          argNames,
   1871                          "_Unwind_RaiseException",
   1872                          llvm::Function::ExternalLinkage,
   1873                          true,
   1874                          false);
   1875 
   1876   funct->setDoesNotReturn();
   1877 
   1878   // _Unwind_Resume
   1879 
   1880   retType = builder.getInt32Ty();
   1881 
   1882   argTypes.clear();
   1883   argTypes.push_back(builder.getInt8PtrTy());
   1884 
   1885   argNames.clear();
   1886 
   1887   funct = createFunction(module,
   1888                          retType,
   1889                          argTypes,
   1890                          argNames,
   1891                          "_Unwind_Resume",
   1892                          llvm::Function::ExternalLinkage,
   1893                          true,
   1894                          false);
   1895 
   1896   funct->setDoesNotReturn();
   1897 
   1898   // ourPersonality
   1899 
   1900   retType = builder.getInt32Ty();
   1901 
   1902   argTypes.clear();
   1903   argTypes.push_back(builder.getInt32Ty());
   1904   argTypes.push_back(builder.getInt32Ty());
   1905   argTypes.push_back(builder.getInt64Ty());
   1906   argTypes.push_back(builder.getInt8PtrTy());
   1907   argTypes.push_back(builder.getInt8PtrTy());
   1908 
   1909   argNames.clear();
   1910 
   1911   createFunction(module,
   1912                  retType,
   1913                  argTypes,
   1914                  argNames,
   1915                  "ourPersonality",
   1916                  llvm::Function::ExternalLinkage,
   1917                  true,
   1918                  false);
   1919 
   1920   // llvm.eh.typeid.for intrinsic
   1921 
   1922   getDeclaration(&module, llvm::Intrinsic::eh_typeid_for);
   1923 }
   1924 
   1925 
   1926 //===----------------------------------------------------------------------===//
   1927 // Main test driver code.
   1928 //===----------------------------------------------------------------------===//
   1929 
   1930 /// Demo main routine which takes the type info types to throw. A test will
   1931 /// be run for each given type info type. While type info types with the value
   1932 /// of -1 will trigger a foreign C++ exception to be thrown; type info types
   1933 /// <= 6 and >= 1 will be caught by test functions; and type info types > 6
   1934 /// will result in exceptions which pass through to the test harness. All other
   1935 /// type info types are not supported and could cause a crash.
   1936 int main(int argc, char *argv[]) {
   1937   if (argc == 1) {
   1938     fprintf(stderr,
   1939             "\nUsage: ExceptionDemo <exception type to throw> "
   1940             "[<type 2>...<type n>].\n"
   1941             "   Each type must have the value of 1 - 6 for "
   1942             "generated exceptions to be caught;\n"
   1943             "   the value -1 for foreign C++ exceptions to be "
   1944             "generated and thrown;\n"
   1945             "   or the values > 6 for exceptions to be ignored.\n"
   1946             "\nTry: ExceptionDemo 2 3 7 -1\n"
   1947             "   for a full test.\n\n");
   1948     return(0);
   1949   }
   1950 
   1951   // If not set, exception handling will not be turned on
   1952   llvm::TargetOptions Opts;
   1953 
   1954   llvm::InitializeNativeTarget();
   1955   llvm::InitializeNativeTargetAsmPrinter();
   1956   llvm::LLVMContext &context = llvm::getGlobalContext();
   1957   llvm::IRBuilder<> theBuilder(context);
   1958 
   1959   // Make the module, which holds all the code.
   1960   llvm::Module *module = new llvm::Module("my cool jit", context);
   1961 
   1962   llvm::RTDyldMemoryManager *MemMgr = new llvm::SectionMemoryManager();
   1963 
   1964   // Build engine with JIT
   1965   llvm::EngineBuilder factory(module);
   1966   factory.setEngineKind(llvm::EngineKind::JIT);
   1967   factory.setAllocateGVsWithCode(false);
   1968   factory.setTargetOptions(Opts);
   1969   factory.setMCJITMemoryManager(MemMgr);
   1970   factory.setUseMCJIT(true);
   1971   llvm::ExecutionEngine *executionEngine = factory.create();
   1972 
   1973   {
   1974     llvm::FunctionPassManager fpm(module);
   1975 
   1976     // Set up the optimizer pipeline.
   1977     // Start with registering info about how the
   1978     // target lays out data structures.
   1979     fpm.add(new llvm::DataLayout(*executionEngine->getDataLayout()));
   1980 
   1981     // Optimizations turned on
   1982 #ifdef ADD_OPT_PASSES
   1983 
   1984     // Basic AliasAnslysis support for GVN.
   1985     fpm.add(llvm::createBasicAliasAnalysisPass());
   1986 
   1987     // Promote allocas to registers.
   1988     fpm.add(llvm::createPromoteMemoryToRegisterPass());
   1989 
   1990     // Do simple "peephole" optimizations and bit-twiddling optzns.
   1991     fpm.add(llvm::createInstructionCombiningPass());
   1992 
   1993     // Reassociate expressions.
   1994     fpm.add(llvm::createReassociatePass());
   1995 
   1996     // Eliminate Common SubExpressions.
   1997     fpm.add(llvm::createGVNPass());
   1998 
   1999     // Simplify the control flow graph (deleting unreachable
   2000     // blocks, etc).
   2001     fpm.add(llvm::createCFGSimplificationPass());
   2002 #endif  // ADD_OPT_PASSES
   2003 
   2004     fpm.doInitialization();
   2005 
   2006     // Generate test code using function throwCppException(...) as
   2007     // the function which throws foreign exceptions.
   2008     llvm::Function *toRun =
   2009     createUnwindExceptionTest(*module,
   2010                               theBuilder,
   2011                               fpm,
   2012                               "throwCppException");
   2013 
   2014     executionEngine->finalizeObject();
   2015 
   2016     fprintf(stderr, "\nBegin module dump:\n\n");
   2017 
   2018     module->dump();
   2019 
   2020     fprintf(stderr, "\nEnd module dump:\n");
   2021 
   2022     fprintf(stderr, "\n\nBegin Test:\n");
   2023 
   2024     for (int i = 1; i < argc; ++i) {
   2025       // Run test for each argument whose value is the exception
   2026       // type to throw.
   2027       runExceptionThrow(executionEngine,
   2028                         toRun,
   2029                         (unsigned) strtoul(argv[i], NULL, 10));
   2030     }
   2031 
   2032     fprintf(stderr, "\nEnd Test:\n\n");
   2033   }
   2034 
   2035   delete executionEngine;
   2036 
   2037   return 0;
   2038 }
   2039