91c2f5c0a1aab799886cd75b307749d427d0a253
[oota-llvm.git] / examples / ExceptionDemo / ExceptionDemo.cpp
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://sourcery.mentor.com/public/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/DataLayout.h"
53 #include "llvm/DerivedTypes.h"
54 #include "llvm/ExecutionEngine/ExecutionEngine.h"
55 #include "llvm/ExecutionEngine/JIT.h"
56 #include "llvm/IRBuilder.h"
57 #include "llvm/Intrinsics.h"
58 #include "llvm/LLVMContext.h"
59 #include "llvm/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://sourcery.mentor.com/public/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://refspecs.freestandards.org/abi-eh-1.21.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 @link http://refspecs.freestandards.org/abi-eh-1.21.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
422 /// Read a pointer encoded value and advance pointer
423 /// See Variable Length Data in:
424 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
425 /// @param data reference variable holding memory pointer to decode from
426 /// @param encoding dwarf encoding type
427 /// @returns decoded value
428 static uintptr_t readEncodedPointer(const uint8_t **data, uint8_t encoding) {
429   uintptr_t result = 0;
430   const uint8_t *p = *data;
431
432   if (encoding == llvm::dwarf::DW_EH_PE_omit)
433     return(result);
434
435   // first get value
436   switch (encoding & 0x0F) {
437     case llvm::dwarf::DW_EH_PE_absptr:
438       result = *((uintptr_t*)p);
439       p += sizeof(uintptr_t);
440       break;
441     case llvm::dwarf::DW_EH_PE_uleb128:
442       result = readULEB128(&p);
443       break;
444       // Note: This case has not been tested
445     case llvm::dwarf::DW_EH_PE_sleb128:
446       result = readSLEB128(&p);
447       break;
448     case llvm::dwarf::DW_EH_PE_udata2:
449       result = *((uint16_t*)p);
450       p += sizeof(uint16_t);
451       break;
452     case llvm::dwarf::DW_EH_PE_udata4:
453       result = *((uint32_t*)p);
454       p += sizeof(uint32_t);
455       break;
456     case llvm::dwarf::DW_EH_PE_udata8:
457       result = *((uint64_t*)p);
458       p += sizeof(uint64_t);
459       break;
460     case llvm::dwarf::DW_EH_PE_sdata2:
461       result = *((int16_t*)p);
462       p += sizeof(int16_t);
463       break;
464     case llvm::dwarf::DW_EH_PE_sdata4:
465       result = *((int32_t*)p);
466       p += sizeof(int32_t);
467       break;
468     case llvm::dwarf::DW_EH_PE_sdata8:
469       result = *((int64_t*)p);
470       p += sizeof(int64_t);
471       break;
472     default:
473       // not supported
474       abort();
475       break;
476   }
477
478   // then add relative offset
479   switch (encoding & 0x70) {
480     case llvm::dwarf::DW_EH_PE_absptr:
481       // do nothing
482       break;
483     case llvm::dwarf::DW_EH_PE_pcrel:
484       result += (uintptr_t)(*data);
485       break;
486     case llvm::dwarf::DW_EH_PE_textrel:
487     case llvm::dwarf::DW_EH_PE_datarel:
488     case llvm::dwarf::DW_EH_PE_funcrel:
489     case llvm::dwarf::DW_EH_PE_aligned:
490     default:
491       // not supported
492       abort();
493       break;
494   }
495
496   // then apply indirection
497   if (encoding & llvm::dwarf::DW_EH_PE_indirect) {
498     result = *((uintptr_t*)result);
499   }
500
501   *data = p;
502
503   return result;
504 }
505
506
507 /// Deals with Dwarf actions matching our type infos
508 /// (OurExceptionType_t instances). Returns whether or not a dwarf emitted
509 /// action matches the supplied exception type. If such a match succeeds,
510 /// the resultAction argument will be set with > 0 index value. Only
511 /// corresponding llvm.eh.selector type info arguments, cleanup arguments
512 /// are supported. Filters are not supported.
513 /// See Variable Length Data in:
514 /// @link http://dwarfstd.org/Dwarf3.pdf @unlink
515 /// Also see @link http://refspecs.freestandards.org/abi-eh-1.21.html @unlink
516 /// @param resultAction reference variable which will be set with result
517 /// @param classInfo our array of type info pointers (to globals)
518 /// @param actionEntry index into above type info array or 0 (clean up).
519 ///        We do not support filters.
520 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
521 ///        of thrown exception.
522 /// @param exceptionObject thrown _Unwind_Exception instance.
523 /// @returns whether or not a type info was found. False is returned if only
524 ///          a cleanup was found
525 static bool handleActionValue(int64_t *resultAction,
526                               struct OurExceptionType_t **classInfo,
527                               uintptr_t actionEntry,
528                               uint64_t exceptionClass,
529                               struct _Unwind_Exception *exceptionObject) {
530   bool ret = false;
531
532   if (!resultAction ||
533       !exceptionObject ||
534       (exceptionClass != ourBaseExceptionClass))
535     return(ret);
536
537   struct OurBaseException_t *excp = (struct OurBaseException_t*)
538   (((char*) exceptionObject) + ourBaseFromUnwindOffset);
539   struct OurExceptionType_t *excpType = &(excp->type);
540   int type = excpType->type;
541
542 #ifdef DEBUG
543   fprintf(stderr,
544           "handleActionValue(...): exceptionObject = <%p>, "
545           "excp = <%p>.\n",
546           exceptionObject,
547           excp);
548 #endif
549
550   const uint8_t *actionPos = (uint8_t*) actionEntry,
551   *tempActionPos;
552   int64_t typeOffset = 0,
553   actionOffset;
554
555   for (int i = 0; true; ++i) {
556     // Each emitted dwarf action corresponds to a 2 tuple of
557     // type info address offset, and action offset to the next
558     // emitted action.
559     typeOffset = readSLEB128(&actionPos);
560     tempActionPos = actionPos;
561     actionOffset = readSLEB128(&tempActionPos);
562
563 #ifdef DEBUG
564     fprintf(stderr,
565             "handleActionValue(...):typeOffset: <%lld>, "
566             "actionOffset: <%lld>.\n",
567             typeOffset,
568             actionOffset);
569 #endif
570     assert((typeOffset >= 0) &&
571            "handleActionValue(...):filters are not supported.");
572
573     // Note: A typeOffset == 0 implies that a cleanup llvm.eh.selector
574     //       argument has been matched.
575     if ((typeOffset > 0) &&
576         (type == (classInfo[-typeOffset])->type)) {
577 #ifdef DEBUG
578       fprintf(stderr,
579               "handleActionValue(...):actionValue <%d> found.\n",
580               i);
581 #endif
582       *resultAction = i + 1;
583       ret = true;
584       break;
585     }
586
587 #ifdef DEBUG
588     fprintf(stderr,
589             "handleActionValue(...):actionValue not found.\n");
590 #endif
591     if (!actionOffset)
592       break;
593
594     actionPos += actionOffset;
595   }
596
597   return(ret);
598 }
599
600
601 /// Deals with the Language specific data portion of the emitted dwarf code.
602 /// See @link http://refspecs.freestandards.org/abi-eh-1.21.html @unlink
603 /// @param version unsupported (ignored), unwind version
604 /// @param lsda language specific data area
605 /// @param _Unwind_Action actions minimally supported unwind stage
606 ///        (forced specifically not supported)
607 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
608 ///        of thrown exception.
609 /// @param exceptionObject thrown _Unwind_Exception instance.
610 /// @param context unwind system context
611 /// @returns minimally supported unwinding control indicator
612 static _Unwind_Reason_Code handleLsda(int version,
613                                       const uint8_t *lsda,
614                                       _Unwind_Action actions,
615                                       uint64_t exceptionClass,
616                                     struct _Unwind_Exception *exceptionObject,
617                                       _Unwind_Context_t context) {
618   _Unwind_Reason_Code ret = _URC_CONTINUE_UNWIND;
619
620   if (!lsda)
621     return(ret);
622
623 #ifdef DEBUG
624   fprintf(stderr,
625           "handleLsda(...):lsda is non-zero.\n");
626 #endif
627
628   // Get the current instruction pointer and offset it before next
629   // instruction in the current frame which threw the exception.
630   uintptr_t pc = _Unwind_GetIP(context)-1;
631
632   // Get beginning current frame's code (as defined by the
633   // emitted dwarf code)
634   uintptr_t funcStart = _Unwind_GetRegionStart(context);
635   uintptr_t pcOffset = pc - funcStart;
636   struct OurExceptionType_t **classInfo = NULL;
637
638   // Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding
639   //       dwarf emission
640
641   // Parse LSDA header.
642   uint8_t lpStartEncoding = *lsda++;
643
644   if (lpStartEncoding != llvm::dwarf::DW_EH_PE_omit) {
645     readEncodedPointer(&lsda, lpStartEncoding);
646   }
647
648   uint8_t ttypeEncoding = *lsda++;
649   uintptr_t classInfoOffset;
650
651   if (ttypeEncoding != llvm::dwarf::DW_EH_PE_omit) {
652     // Calculate type info locations in emitted dwarf code which
653     // were flagged by type info arguments to llvm.eh.selector
654     // intrinsic
655     classInfoOffset = readULEB128(&lsda);
656     classInfo = (struct OurExceptionType_t**) (lsda + classInfoOffset);
657   }
658
659   // Walk call-site table looking for range that
660   // includes current PC.
661
662   uint8_t         callSiteEncoding = *lsda++;
663   uint32_t        callSiteTableLength = readULEB128(&lsda);
664   const uint8_t   *callSiteTableStart = lsda;
665   const uint8_t   *callSiteTableEnd = callSiteTableStart +
666   callSiteTableLength;
667   const uint8_t   *actionTableStart = callSiteTableEnd;
668   const uint8_t   *callSitePtr = callSiteTableStart;
669
670   while (callSitePtr < callSiteTableEnd) {
671     uintptr_t start = readEncodedPointer(&callSitePtr,
672                                          callSiteEncoding);
673     uintptr_t length = readEncodedPointer(&callSitePtr,
674                                           callSiteEncoding);
675     uintptr_t landingPad = readEncodedPointer(&callSitePtr,
676                                               callSiteEncoding);
677
678     // Note: Action value
679     uintptr_t actionEntry = readULEB128(&callSitePtr);
680
681     if (exceptionClass != ourBaseExceptionClass) {
682       // We have been notified of a foreign exception being thrown,
683       // and we therefore need to execute cleanup landing pads
684       actionEntry = 0;
685     }
686
687     if (landingPad == 0) {
688 #ifdef DEBUG
689       fprintf(stderr,
690               "handleLsda(...): No landing pad found.\n");
691 #endif
692
693       continue; // no landing pad for this entry
694     }
695
696     if (actionEntry) {
697       actionEntry += ((uintptr_t) actionTableStart) - 1;
698     }
699     else {
700 #ifdef DEBUG
701       fprintf(stderr,
702               "handleLsda(...):No action table found.\n");
703 #endif
704     }
705
706     bool exceptionMatched = false;
707
708     if ((start <= pcOffset) && (pcOffset < (start + length))) {
709 #ifdef DEBUG
710       fprintf(stderr,
711               "handleLsda(...): Landing pad found.\n");
712 #endif
713       int64_t actionValue = 0;
714
715       if (actionEntry) {
716         exceptionMatched = handleActionValue(&actionValue,
717                                              classInfo,
718                                              actionEntry,
719                                              exceptionClass,
720                                              exceptionObject);
721       }
722
723       if (!(actions & _UA_SEARCH_PHASE)) {
724 #ifdef DEBUG
725         fprintf(stderr,
726                 "handleLsda(...): installed landing pad "
727                 "context.\n");
728 #endif
729
730         // Found landing pad for the PC.
731         // Set Instruction Pointer to so we re-enter function
732         // at landing pad. The landing pad is created by the
733         // compiler to take two parameters in registers.
734         _Unwind_SetGR(context,
735                       __builtin_eh_return_data_regno(0),
736                       (uintptr_t)exceptionObject);
737
738         // Note: this virtual register directly corresponds
739         //       to the return of the llvm.eh.selector intrinsic
740         if (!actionEntry || !exceptionMatched) {
741           // We indicate cleanup only
742           _Unwind_SetGR(context,
743                         __builtin_eh_return_data_regno(1),
744                         0);
745         }
746         else {
747           // Matched type info index of llvm.eh.selector intrinsic
748           // passed here.
749           _Unwind_SetGR(context,
750                         __builtin_eh_return_data_regno(1),
751                         actionValue);
752         }
753
754         // To execute landing pad set here
755         _Unwind_SetIP(context, funcStart + landingPad);
756         ret = _URC_INSTALL_CONTEXT;
757       }
758       else if (exceptionMatched) {
759 #ifdef DEBUG
760         fprintf(stderr,
761                 "handleLsda(...): setting handler found.\n");
762 #endif
763         ret = _URC_HANDLER_FOUND;
764       }
765       else {
766         // Note: Only non-clean up handlers are marked as
767         //       found. Otherwise the clean up handlers will be
768         //       re-found and executed during the clean up
769         //       phase.
770 #ifdef DEBUG
771         fprintf(stderr,
772                 "handleLsda(...): cleanup handler found.\n");
773 #endif
774       }
775
776       break;
777     }
778   }
779
780   return(ret);
781 }
782
783
784 /// This is the personality function which is embedded (dwarf emitted), in the
785 /// dwarf unwind info block. Again see: JITDwarfEmitter.cpp.
786 /// See @link http://refspecs.freestandards.org/abi-eh-1.21.html @unlink
787 /// @param version unsupported (ignored), unwind version
788 /// @param _Unwind_Action actions minimally supported unwind stage
789 ///        (forced specifically not supported)
790 /// @param exceptionClass exception class (_Unwind_Exception::exception_class)
791 ///        of thrown exception.
792 /// @param exceptionObject thrown _Unwind_Exception instance.
793 /// @param context unwind system context
794 /// @returns minimally supported unwinding control indicator
795 _Unwind_Reason_Code ourPersonality(int version,
796                                    _Unwind_Action actions,
797                                    uint64_t exceptionClass,
798                                    struct _Unwind_Exception *exceptionObject,
799                                    _Unwind_Context_t context) {
800 #ifdef DEBUG
801   fprintf(stderr,
802           "We are in ourPersonality(...):actions is <%d>.\n",
803           actions);
804
805   if (actions & _UA_SEARCH_PHASE) {
806     fprintf(stderr, "ourPersonality(...):In search phase.\n");
807   }
808   else {
809     fprintf(stderr, "ourPersonality(...):In non-search phase.\n");
810   }
811 #endif
812
813   const uint8_t *lsda = _Unwind_GetLanguageSpecificData(context);
814
815 #ifdef DEBUG
816   fprintf(stderr,
817           "ourPersonality(...):lsda = <%p>.\n",
818           lsda);
819 #endif
820
821   // The real work of the personality function is captured here
822   return(handleLsda(version,
823                     lsda,
824                     actions,
825                     exceptionClass,
826                     exceptionObject,
827                     context));
828 }
829
830
831 /// Generates our _Unwind_Exception class from a given character array.
832 /// thereby handling arbitrary lengths (not in standard), and handling
833 /// embedded \0s.
834 /// See @link http://refspecs.freestandards.org/abi-eh-1.21.html @unlink
835 /// @param classChars char array to encode. NULL values not checkedf
836 /// @param classCharsSize number of chars in classChars. Value is not checked.
837 /// @returns class value
838 uint64_t genClass(const unsigned char classChars[], size_t classCharsSize)
839 {
840   uint64_t ret = classChars[0];
841
842   for (unsigned i = 1; i < classCharsSize; ++i) {
843     ret <<= 8;
844     ret += classChars[i];
845   }
846
847   return(ret);
848 }
849
850 } // extern "C"
851
852 //
853 // Runtime C Library functions End
854 //
855
856 //
857 // Code generation functions
858 //
859
860 /// Generates code to print given constant string
861 /// @param context llvm context
862 /// @param module code for module instance
863 /// @param builder builder instance
864 /// @param toPrint string to print
865 /// @param useGlobal A value of true (default) indicates a GlobalValue is
866 ///        generated, and is used to hold the constant string. A value of
867 ///        false indicates that the constant string will be stored on the
868 ///        stack.
869 void generateStringPrint(llvm::LLVMContext &context,
870                          llvm::Module &module,
871                          llvm::IRBuilder<> &builder,
872                          std::string toPrint,
873                          bool useGlobal = true) {
874   llvm::Function *printFunct = module.getFunction("printStr");
875
876   llvm::Value *stringVar;
877   llvm::Constant *stringConstant =
878   llvm::ConstantDataArray::getString(context, toPrint);
879
880   if (useGlobal) {
881     // Note: Does not work without allocation
882     stringVar =
883     new llvm::GlobalVariable(module,
884                              stringConstant->getType(),
885                              true,
886                              llvm::GlobalValue::LinkerPrivateLinkage,
887                              stringConstant,
888                              "");
889   }
890   else {
891     stringVar = builder.CreateAlloca(stringConstant->getType());
892     builder.CreateStore(stringConstant, stringVar);
893   }
894
895   llvm::Value *cast = builder.CreatePointerCast(stringVar,
896                                                 builder.getInt8PtrTy());
897   builder.CreateCall(printFunct, cast);
898 }
899
900
901 /// Generates code to print given runtime integer according to constant
902 /// string format, and a given print function.
903 /// @param context llvm context
904 /// @param module code for module instance
905 /// @param builder builder instance
906 /// @param printFunct function used to "print" integer
907 /// @param toPrint string to print
908 /// @param format printf like formating string for print
909 /// @param useGlobal A value of true (default) indicates a GlobalValue is
910 ///        generated, and is used to hold the constant string. A value of
911 ///        false indicates that the constant string will be stored on the
912 ///        stack.
913 void generateIntegerPrint(llvm::LLVMContext &context,
914                           llvm::Module &module,
915                           llvm::IRBuilder<> &builder,
916                           llvm::Function &printFunct,
917                           llvm::Value &toPrint,
918                           std::string format,
919                           bool useGlobal = true) {
920   llvm::Constant *stringConstant =
921     llvm::ConstantDataArray::getString(context, format);
922   llvm::Value *stringVar;
923
924   if (useGlobal) {
925     // Note: Does not seem to work without allocation
926     stringVar =
927     new llvm::GlobalVariable(module,
928                              stringConstant->getType(),
929                              true,
930                              llvm::GlobalValue::LinkerPrivateLinkage,
931                              stringConstant,
932                              "");
933   }
934   else {
935     stringVar = builder.CreateAlloca(stringConstant->getType());
936     builder.CreateStore(stringConstant, stringVar);
937   }
938
939   llvm::Value *cast = builder.CreateBitCast(stringVar,
940                                             builder.getInt8PtrTy());
941   builder.CreateCall2(&printFunct, &toPrint, cast);
942 }
943
944
945 /// Generates code to handle finally block type semantics: always runs
946 /// regardless of whether a thrown exception is passing through or the
947 /// parent function is simply exiting. In addition to printing some state
948 /// to stderr, this code will resume the exception handling--runs the
949 /// unwind resume block, if the exception has not been previously caught
950 /// by a catch clause, and will otherwise execute the end block (terminator
951 /// block). In addition this function creates the corresponding function's
952 /// stack storage for the exception pointer and catch flag status.
953 /// @param context llvm context
954 /// @param module code for module instance
955 /// @param builder builder instance
956 /// @param toAddTo parent function to add block to
957 /// @param blockName block name of new "finally" block.
958 /// @param functionId output id used for printing
959 /// @param terminatorBlock terminator "end" block
960 /// @param unwindResumeBlock unwind resume block
961 /// @param exceptionCaughtFlag reference exception caught/thrown status storage
962 /// @param exceptionStorage reference to exception pointer storage
963 /// @param caughtResultStorage reference to landingpad result storage
964 /// @returns newly created block
965 static llvm::BasicBlock *createFinallyBlock(llvm::LLVMContext &context,
966                                             llvm::Module &module,
967                                             llvm::IRBuilder<> &builder,
968                                             llvm::Function &toAddTo,
969                                             std::string &blockName,
970                                             std::string &functionId,
971                                             llvm::BasicBlock &terminatorBlock,
972                                             llvm::BasicBlock &unwindResumeBlock,
973                                             llvm::Value **exceptionCaughtFlag,
974                                             llvm::Value **exceptionStorage,
975                                             llvm::Value **caughtResultStorage) {
976   assert(exceptionCaughtFlag &&
977          "ExceptionDemo::createFinallyBlock(...):exceptionCaughtFlag "
978          "is NULL");
979   assert(exceptionStorage &&
980          "ExceptionDemo::createFinallyBlock(...):exceptionStorage "
981          "is NULL");
982   assert(caughtResultStorage &&
983          "ExceptionDemo::createFinallyBlock(...):caughtResultStorage "
984          "is NULL");
985
986   *exceptionCaughtFlag = createEntryBlockAlloca(toAddTo,
987                                          "exceptionCaught",
988                                          ourExceptionNotThrownState->getType(),
989                                          ourExceptionNotThrownState);
990
991   llvm::PointerType *exceptionStorageType = builder.getInt8PtrTy();
992   *exceptionStorage = createEntryBlockAlloca(toAddTo,
993                                              "exceptionStorage",
994                                              exceptionStorageType,
995                                              llvm::ConstantPointerNull::get(
996                                                exceptionStorageType));
997   *caughtResultStorage = createEntryBlockAlloca(toAddTo,
998                                               "caughtResultStorage",
999                                               ourCaughtResultType,
1000                                               llvm::ConstantAggregateZero::get(
1001                                                 ourCaughtResultType));
1002
1003   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
1004                                                    blockName,
1005                                                    &toAddTo);
1006
1007   builder.SetInsertPoint(ret);
1008
1009   std::ostringstream bufferToPrint;
1010   bufferToPrint << "Gen: Executing finally block "
1011     << blockName << " in " << functionId << "\n";
1012   generateStringPrint(context,
1013                       module,
1014                       builder,
1015                       bufferToPrint.str(),
1016                       USE_GLOBAL_STR_CONSTS);
1017
1018   llvm::SwitchInst *theSwitch = builder.CreateSwitch(builder.CreateLoad(
1019                                                        *exceptionCaughtFlag),
1020                                                      &terminatorBlock,
1021                                                      2);
1022   theSwitch->addCase(ourExceptionCaughtState, &terminatorBlock);
1023   theSwitch->addCase(ourExceptionThrownState, &unwindResumeBlock);
1024
1025   return(ret);
1026 }
1027
1028
1029 /// Generates catch block semantics which print a string to indicate type of
1030 /// catch executed, sets an exception caught flag, and executes passed in
1031 /// end block (terminator block).
1032 /// @param context llvm context
1033 /// @param module code for module instance
1034 /// @param builder builder instance
1035 /// @param toAddTo parent function to add block to
1036 /// @param blockName block name of new "catch" block.
1037 /// @param functionId output id used for printing
1038 /// @param terminatorBlock terminator "end" block
1039 /// @param exceptionCaughtFlag exception caught/thrown status
1040 /// @returns newly created block
1041 static llvm::BasicBlock *createCatchBlock(llvm::LLVMContext &context,
1042                                           llvm::Module &module,
1043                                           llvm::IRBuilder<> &builder,
1044                                           llvm::Function &toAddTo,
1045                                           std::string &blockName,
1046                                           std::string &functionId,
1047                                           llvm::BasicBlock &terminatorBlock,
1048                                           llvm::Value &exceptionCaughtFlag) {
1049
1050   llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
1051                                                    blockName,
1052                                                    &toAddTo);
1053
1054   builder.SetInsertPoint(ret);
1055
1056   std::ostringstream bufferToPrint;
1057   bufferToPrint << "Gen: Executing catch block "
1058   << blockName
1059   << " in "
1060   << functionId
1061   << std::endl;
1062   generateStringPrint(context,
1063                       module,
1064                       builder,
1065                       bufferToPrint.str(),
1066                       USE_GLOBAL_STR_CONSTS);
1067   builder.CreateStore(ourExceptionCaughtState, &exceptionCaughtFlag);
1068   builder.CreateBr(&terminatorBlock);
1069
1070   return(ret);
1071 }
1072
1073
1074 /// Generates a function which invokes a function (toInvoke) and, whose
1075 /// unwind block will "catch" the type info types correspondingly held in the
1076 /// exceptionTypesToCatch argument. If the toInvoke function throws an
1077 /// exception which does not match any type info types contained in
1078 /// exceptionTypesToCatch, the generated code will call _Unwind_Resume
1079 /// with the raised exception. On the other hand the generated code will
1080 /// normally exit if the toInvoke function does not throw an exception.
1081 /// The generated "finally" block is always run regardless of the cause of
1082 /// the generated function exit.
1083 /// The generated function is returned after being verified.
1084 /// @param module code for module instance
1085 /// @param builder builder instance
1086 /// @param fpm a function pass manager holding optional IR to IR
1087 ///        transformations
1088 /// @param toInvoke inner function to invoke
1089 /// @param ourId id used to printing purposes
1090 /// @param numExceptionsToCatch length of exceptionTypesToCatch array
1091 /// @param exceptionTypesToCatch array of type info types to "catch"
1092 /// @returns generated function
1093 static
1094 llvm::Function *createCatchWrappedInvokeFunction(llvm::Module &module,
1095                                              llvm::IRBuilder<> &builder,
1096                                              llvm::FunctionPassManager &fpm,
1097                                              llvm::Function &toInvoke,
1098                                              std::string ourId,
1099                                              unsigned numExceptionsToCatch,
1100                                              unsigned exceptionTypesToCatch[]) {
1101
1102   llvm::LLVMContext &context = module.getContext();
1103   llvm::Function *toPrint32Int = module.getFunction("print32Int");
1104
1105   ArgTypes argTypes;
1106   argTypes.push_back(builder.getInt32Ty());
1107
1108   ArgNames argNames;
1109   argNames.push_back("exceptTypeToThrow");
1110
1111   llvm::Function *ret = createFunction(module,
1112                                        builder.getVoidTy(),
1113                                        argTypes,
1114                                        argNames,
1115                                        ourId,
1116                                        llvm::Function::ExternalLinkage,
1117                                        false,
1118                                        false);
1119
1120   // Block which calls invoke
1121   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
1122                                                           "entry",
1123                                                           ret);
1124   // Normal block for invoke
1125   llvm::BasicBlock *normalBlock = llvm::BasicBlock::Create(context,
1126                                                            "normal",
1127                                                            ret);
1128   // Unwind block for invoke
1129   llvm::BasicBlock *exceptionBlock = llvm::BasicBlock::Create(context,
1130                                                               "exception",
1131                                                               ret);
1132
1133   // Block which routes exception to correct catch handler block
1134   llvm::BasicBlock *exceptionRouteBlock = llvm::BasicBlock::Create(context,
1135                                                              "exceptionRoute",
1136                                                              ret);
1137
1138   // Foreign exception handler
1139   llvm::BasicBlock *externalExceptionBlock = llvm::BasicBlock::Create(context,
1140                                                           "externalException",
1141                                                           ret);
1142
1143   // Block which calls _Unwind_Resume
1144   llvm::BasicBlock *unwindResumeBlock = llvm::BasicBlock::Create(context,
1145                                                                "unwindResume",
1146                                                                ret);
1147
1148   // Clean up block which delete exception if needed
1149   llvm::BasicBlock *endBlock = llvm::BasicBlock::Create(context, "end", ret);
1150
1151   std::string nextName;
1152   std::vector<llvm::BasicBlock*> catchBlocks(numExceptionsToCatch);
1153   llvm::Value *exceptionCaughtFlag = NULL;
1154   llvm::Value *exceptionStorage = NULL;
1155   llvm::Value *caughtResultStorage = NULL;
1156
1157   // Finally block which will branch to unwindResumeBlock if
1158   // exception is not caught. Initializes/allocates stack locations.
1159   llvm::BasicBlock *finallyBlock = createFinallyBlock(context,
1160                                                       module,
1161                                                       builder,
1162                                                       *ret,
1163                                                       nextName = "finally",
1164                                                       ourId,
1165                                                       *endBlock,
1166                                                       *unwindResumeBlock,
1167                                                       &exceptionCaughtFlag,
1168                                                       &exceptionStorage,
1169                                                       &caughtResultStorage
1170                                                       );
1171
1172   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
1173     nextName = ourTypeInfoNames[exceptionTypesToCatch[i]];
1174
1175     // One catch block per type info to be caught
1176     catchBlocks[i] = createCatchBlock(context,
1177                                       module,
1178                                       builder,
1179                                       *ret,
1180                                       nextName,
1181                                       ourId,
1182                                       *finallyBlock,
1183                                       *exceptionCaughtFlag);
1184   }
1185
1186   // Entry Block
1187
1188   builder.SetInsertPoint(entryBlock);
1189
1190   std::vector<llvm::Value*> args;
1191   args.push_back(namedValues["exceptTypeToThrow"]);
1192   builder.CreateInvoke(&toInvoke,
1193                        normalBlock,
1194                        exceptionBlock,
1195                        args);
1196
1197   // End Block
1198
1199   builder.SetInsertPoint(endBlock);
1200
1201   generateStringPrint(context,
1202                       module,
1203                       builder,
1204                       "Gen: In end block: exiting in " + ourId + ".\n",
1205                       USE_GLOBAL_STR_CONSTS);
1206   llvm::Function *deleteOurException = module.getFunction("deleteOurException");
1207
1208   // Note: function handles NULL exceptions
1209   builder.CreateCall(deleteOurException,
1210                      builder.CreateLoad(exceptionStorage));
1211   builder.CreateRetVoid();
1212
1213   // Normal Block
1214
1215   builder.SetInsertPoint(normalBlock);
1216
1217   generateStringPrint(context,
1218                       module,
1219                       builder,
1220                       "Gen: No exception in " + ourId + "!\n",
1221                       USE_GLOBAL_STR_CONSTS);
1222
1223   // Finally block is always called
1224   builder.CreateBr(finallyBlock);
1225
1226   // Unwind Resume Block
1227
1228   builder.SetInsertPoint(unwindResumeBlock);
1229
1230   builder.CreateResume(builder.CreateLoad(caughtResultStorage));
1231
1232   // Exception Block
1233
1234   builder.SetInsertPoint(exceptionBlock);
1235
1236   llvm::Function *personality = module.getFunction("ourPersonality");
1237
1238   llvm::LandingPadInst *caughtResult =
1239     builder.CreateLandingPad(ourCaughtResultType,
1240                              personality,
1241                              numExceptionsToCatch,
1242                              "landingPad");
1243
1244   caughtResult->setCleanup(true);
1245
1246   for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
1247     // Set up type infos to be caught
1248     caughtResult->addClause(module.getGlobalVariable(
1249                              ourTypeInfoNames[exceptionTypesToCatch[i]]));
1250   }
1251
1252   llvm::Value *unwindException = builder.CreateExtractValue(caughtResult, 0);
1253   llvm::Value *retTypeInfoIndex = builder.CreateExtractValue(caughtResult, 1);
1254
1255   // FIXME: Redundant storage which, beyond utilizing value of
1256   //        caughtResultStore for unwindException storage, may be alleviated
1257   //        altogether with a block rearrangement
1258   builder.CreateStore(caughtResult, caughtResultStorage);
1259   builder.CreateStore(unwindException, exceptionStorage);
1260   builder.CreateStore(ourExceptionThrownState, exceptionCaughtFlag);
1261
1262   // Retrieve exception_class member from thrown exception
1263   // (_Unwind_Exception instance). This member tells us whether or not
1264   // the exception is foreign.
1265   llvm::Value *unwindExceptionClass =
1266     builder.CreateLoad(builder.CreateStructGEP(
1267              builder.CreatePointerCast(unwindException,
1268                                        ourUnwindExceptionType->getPointerTo()),
1269                                                0));
1270
1271   // Branch to the externalExceptionBlock if the exception is foreign or
1272   // to a catch router if not. Either way the finally block will be run.
1273   builder.CreateCondBr(builder.CreateICmpEQ(unwindExceptionClass,
1274                             llvm::ConstantInt::get(builder.getInt64Ty(),
1275                                                    ourBaseExceptionClass)),
1276                        exceptionRouteBlock,
1277                        externalExceptionBlock);
1278
1279   // External Exception Block
1280
1281   builder.SetInsertPoint(externalExceptionBlock);
1282
1283   generateStringPrint(context,
1284                       module,
1285                       builder,
1286                       "Gen: Foreign exception received.\n",
1287                       USE_GLOBAL_STR_CONSTS);
1288
1289   // Branch to the finally block
1290   builder.CreateBr(finallyBlock);
1291
1292   // Exception Route Block
1293
1294   builder.SetInsertPoint(exceptionRouteBlock);
1295
1296   // Casts exception pointer (_Unwind_Exception instance) to parent
1297   // (OurException instance).
1298   //
1299   // Note: ourBaseFromUnwindOffset is usually negative
1300   llvm::Value *typeInfoThrown = builder.CreatePointerCast(
1301                                   builder.CreateConstGEP1_64(unwindException,
1302                                                        ourBaseFromUnwindOffset),
1303                                   ourExceptionType->getPointerTo());
1304
1305   // Retrieve thrown exception type info type
1306   //
1307   // Note: Index is not relative to pointer but instead to structure
1308   //       unlike a true getelementptr (GEP) instruction
1309   typeInfoThrown = builder.CreateStructGEP(typeInfoThrown, 0);
1310
1311   llvm::Value *typeInfoThrownType =
1312   builder.CreateStructGEP(typeInfoThrown, 0);
1313
1314   generateIntegerPrint(context,
1315                        module,
1316                        builder,
1317                        *toPrint32Int,
1318                        *(builder.CreateLoad(typeInfoThrownType)),
1319                        "Gen: Exception type <%d> received (stack unwound) "
1320                        " in " +
1321                        ourId +
1322                        ".\n",
1323                        USE_GLOBAL_STR_CONSTS);
1324
1325   // Route to matched type info catch block or run cleanup finally block
1326   llvm::SwitchInst *switchToCatchBlock = builder.CreateSwitch(retTypeInfoIndex,
1327                                                           finallyBlock,
1328                                                           numExceptionsToCatch);
1329
1330   unsigned nextTypeToCatch;
1331
1332   for (unsigned i = 1; i <= numExceptionsToCatch; ++i) {
1333     nextTypeToCatch = i - 1;
1334     switchToCatchBlock->addCase(llvm::ConstantInt::get(
1335                                    llvm::Type::getInt32Ty(context), i),
1336                                 catchBlocks[nextTypeToCatch]);
1337   }
1338
1339   llvm::verifyFunction(*ret);
1340   fpm.run(*ret);
1341
1342   return(ret);
1343 }
1344
1345
1346 /// Generates function which throws either an exception matched to a runtime
1347 /// determined type info type (argument to generated function), or if this
1348 /// runtime value matches nativeThrowType, throws a foreign exception by
1349 /// calling nativeThrowFunct.
1350 /// @param module code for module instance
1351 /// @param builder builder instance
1352 /// @param fpm a function pass manager holding optional IR to IR
1353 ///        transformations
1354 /// @param ourId id used to printing purposes
1355 /// @param nativeThrowType a runtime argument of this value results in
1356 ///        nativeThrowFunct being called to generate/throw exception.
1357 /// @param nativeThrowFunct function which will throw a foreign exception
1358 ///        if the above nativeThrowType matches generated function's arg.
1359 /// @returns generated function
1360 static
1361 llvm::Function *createThrowExceptionFunction(llvm::Module &module,
1362                                              llvm::IRBuilder<> &builder,
1363                                              llvm::FunctionPassManager &fpm,
1364                                              std::string ourId,
1365                                              int32_t nativeThrowType,
1366                                              llvm::Function &nativeThrowFunct) {
1367   llvm::LLVMContext &context = module.getContext();
1368   namedValues.clear();
1369   ArgTypes unwindArgTypes;
1370   unwindArgTypes.push_back(builder.getInt32Ty());
1371   ArgNames unwindArgNames;
1372   unwindArgNames.push_back("exceptTypeToThrow");
1373
1374   llvm::Function *ret = createFunction(module,
1375                                        builder.getVoidTy(),
1376                                        unwindArgTypes,
1377                                        unwindArgNames,
1378                                        ourId,
1379                                        llvm::Function::ExternalLinkage,
1380                                        false,
1381                                        false);
1382
1383   // Throws either one of our exception or a native C++ exception depending
1384   // on a runtime argument value containing a type info type.
1385   llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
1386                                                           "entry",
1387                                                           ret);
1388   // Throws a foreign exception
1389   llvm::BasicBlock *nativeThrowBlock = llvm::BasicBlock::Create(context,
1390                                                                 "nativeThrow",
1391                                                                 ret);
1392   // Throws one of our Exceptions
1393   llvm::BasicBlock *generatedThrowBlock = llvm::BasicBlock::Create(context,
1394                                                              "generatedThrow",
1395                                                              ret);
1396   // Retrieved runtime type info type to throw
1397   llvm::Value *exceptionType = namedValues["exceptTypeToThrow"];
1398
1399   // nativeThrowBlock block
1400
1401   builder.SetInsertPoint(nativeThrowBlock);
1402
1403   // Throws foreign exception
1404   builder.CreateCall(&nativeThrowFunct, exceptionType);
1405   builder.CreateUnreachable();
1406
1407   // entry block
1408
1409   builder.SetInsertPoint(entryBlock);
1410
1411   llvm::Function *toPrint32Int = module.getFunction("print32Int");
1412   generateIntegerPrint(context,
1413                        module,
1414                        builder,
1415                        *toPrint32Int,
1416                        *exceptionType,
1417                        "\nGen: About to throw exception type <%d> in " +
1418                        ourId +
1419                        ".\n",
1420                        USE_GLOBAL_STR_CONSTS);
1421
1422   // Switches on runtime type info type value to determine whether or not
1423   // a foreign exception is thrown. Defaults to throwing one of our
1424   // generated exceptions.
1425   llvm::SwitchInst *theSwitch = builder.CreateSwitch(exceptionType,
1426                                                      generatedThrowBlock,
1427                                                      1);
1428
1429   theSwitch->addCase(llvm::ConstantInt::get(llvm::Type::getInt32Ty(context),
1430                                             nativeThrowType),
1431                      nativeThrowBlock);
1432
1433   // generatedThrow block
1434
1435   builder.SetInsertPoint(generatedThrowBlock);
1436
1437   llvm::Function *createOurException = module.getFunction("createOurException");
1438   llvm::Function *raiseOurException = module.getFunction(
1439                                         "_Unwind_RaiseException");
1440
1441   // Creates exception to throw with runtime type info type.
1442   llvm::Value *exception = builder.CreateCall(createOurException,
1443                                               namedValues["exceptTypeToThrow"]);
1444
1445   // Throw generated Exception
1446   builder.CreateCall(raiseOurException, exception);
1447   builder.CreateUnreachable();
1448
1449   llvm::verifyFunction(*ret);
1450   fpm.run(*ret);
1451
1452   return(ret);
1453 }
1454
1455 static void createStandardUtilityFunctions(unsigned numTypeInfos,
1456                                            llvm::Module &module,
1457                                            llvm::IRBuilder<> &builder);
1458
1459 /// Creates test code by generating and organizing these functions into the
1460 /// test case. The test case consists of an outer function setup to invoke
1461 /// an inner function within an environment having multiple catch and single
1462 /// finally blocks. This inner function is also setup to invoke a throw
1463 /// function within an evironment similar in nature to the outer function's
1464 /// catch and finally blocks. Each of these two functions catch mutually
1465 /// exclusive subsets (even or odd) of the type info types configured
1466 /// for this this. All generated functions have a runtime argument which
1467 /// holds a type info type to throw that each function takes and passes it
1468 /// to the inner one if such a inner function exists. This type info type is
1469 /// looked at by the generated throw function to see whether or not it should
1470 /// throw a generated exception with the same type info type, or instead call
1471 /// a supplied a function which in turn will throw a foreign exception.
1472 /// @param module code for module instance
1473 /// @param builder builder instance
1474 /// @param fpm a function pass manager holding optional IR to IR
1475 ///        transformations
1476 /// @param nativeThrowFunctName name of external function which will throw
1477 ///        a foreign exception
1478 /// @returns outermost generated test function.
1479 llvm::Function *createUnwindExceptionTest(llvm::Module &module,
1480                                           llvm::IRBuilder<> &builder,
1481                                           llvm::FunctionPassManager &fpm,
1482                                           std::string nativeThrowFunctName) {
1483   // Number of type infos to generate
1484   unsigned numTypeInfos = 6;
1485
1486   // Initialze intrisics and external functions to use along with exception
1487   // and type info globals.
1488   createStandardUtilityFunctions(numTypeInfos,
1489                                  module,
1490                                  builder);
1491   llvm::Function *nativeThrowFunct = module.getFunction(nativeThrowFunctName);
1492
1493   // Create exception throw function using the value ~0 to cause
1494   // foreign exceptions to be thrown.
1495   llvm::Function *throwFunct = createThrowExceptionFunction(module,
1496                                                             builder,
1497                                                             fpm,
1498                                                             "throwFunct",
1499                                                             ~0,
1500                                                             *nativeThrowFunct);
1501   // Inner function will catch even type infos
1502   unsigned innerExceptionTypesToCatch[] = {6, 2, 4};
1503   size_t numExceptionTypesToCatch = sizeof(innerExceptionTypesToCatch) /
1504                                     sizeof(unsigned);
1505
1506   // Generate inner function.
1507   llvm::Function *innerCatchFunct = createCatchWrappedInvokeFunction(module,
1508                                                     builder,
1509                                                     fpm,
1510                                                     *throwFunct,
1511                                                     "innerCatchFunct",
1512                                                     numExceptionTypesToCatch,
1513                                                     innerExceptionTypesToCatch);
1514
1515   // Outer function will catch odd type infos
1516   unsigned outerExceptionTypesToCatch[] = {3, 1, 5};
1517   numExceptionTypesToCatch = sizeof(outerExceptionTypesToCatch) /
1518   sizeof(unsigned);
1519
1520   // Generate outer function
1521   llvm::Function *outerCatchFunct = createCatchWrappedInvokeFunction(module,
1522                                                     builder,
1523                                                     fpm,
1524                                                     *innerCatchFunct,
1525                                                     "outerCatchFunct",
1526                                                     numExceptionTypesToCatch,
1527                                                     outerExceptionTypesToCatch);
1528
1529   // Return outer function to run
1530   return(outerCatchFunct);
1531 }
1532
1533
1534 /// Represents our foreign exceptions
1535 class OurCppRunException : public std::runtime_error {
1536 public:
1537   OurCppRunException(const std::string reason) :
1538   std::runtime_error(reason) {}
1539
1540   OurCppRunException (const OurCppRunException &toCopy) :
1541   std::runtime_error(toCopy) {}
1542
1543   OurCppRunException &operator = (const OurCppRunException &toCopy) {
1544     return(reinterpret_cast<OurCppRunException&>(
1545                                  std::runtime_error::operator=(toCopy)));
1546   }
1547
1548   ~OurCppRunException (void) throw () {}
1549 };
1550
1551
1552 /// Throws foreign C++ exception.
1553 /// @param ignoreIt unused parameter that allows function to match implied
1554 ///        generated function contract.
1555 extern "C"
1556 void throwCppException (int32_t ignoreIt) {
1557   throw(OurCppRunException("thrown by throwCppException(...)"));
1558 }
1559
1560 typedef void (*OurExceptionThrowFunctType) (int32_t typeToThrow);
1561
1562 /// This is a test harness which runs test by executing generated
1563 /// function with a type info type to throw. Harness wraps the execution
1564 /// of generated function in a C++ try catch clause.
1565 /// @param engine execution engine to use for executing generated function.
1566 ///        This demo program expects this to be a JIT instance for demo
1567 ///        purposes.
1568 /// @param function generated test function to run
1569 /// @param typeToThrow type info type of generated exception to throw, or
1570 ///        indicator to cause foreign exception to be thrown.
1571 static
1572 void runExceptionThrow(llvm::ExecutionEngine *engine,
1573                        llvm::Function *function,
1574                        int32_t typeToThrow) {
1575
1576   // Find test's function pointer
1577   OurExceptionThrowFunctType functPtr =
1578     reinterpret_cast<OurExceptionThrowFunctType>(
1579        reinterpret_cast<intptr_t>(engine->getPointerToFunction(function)));
1580
1581   try {
1582     // Run test
1583     (*functPtr)(typeToThrow);
1584   }
1585   catch (OurCppRunException exc) {
1586     // Catch foreign C++ exception
1587     fprintf(stderr,
1588             "\nrunExceptionThrow(...):In C++ catch OurCppRunException "
1589             "with reason: %s.\n",
1590             exc.what());
1591   }
1592   catch (...) {
1593     // Catch all exceptions including our generated ones. This latter
1594     // functionality works according to the example in rules 1.6.4 of
1595     // http://sourcery.mentor.com/public/cxx-abi/abi-eh.html (v1.22),
1596     // given that these will be exceptions foreign to C++
1597     // (the _Unwind_Exception::exception_class should be different from
1598     // the one used by C++).
1599     fprintf(stderr,
1600             "\nrunExceptionThrow(...):In C++ catch all.\n");
1601   }
1602 }
1603
1604 //
1605 // End test functions
1606 //
1607
1608 typedef llvm::ArrayRef<llvm::Type*> TypeArray;
1609
1610 /// This initialization routine creates type info globals and
1611 /// adds external function declarations to module.
1612 /// @param numTypeInfos number of linear type info associated type info types
1613 ///        to create as GlobalVariable instances, starting with the value 1.
1614 /// @param module code for module instance
1615 /// @param builder builder instance
1616 static void createStandardUtilityFunctions(unsigned numTypeInfos,
1617                                            llvm::Module &module,
1618                                            llvm::IRBuilder<> &builder) {
1619
1620   llvm::LLVMContext &context = module.getContext();
1621
1622   // Exception initializations
1623
1624   // Setup exception catch state
1625   ourExceptionNotThrownState =
1626     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 0),
1627   ourExceptionThrownState =
1628     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 1),
1629   ourExceptionCaughtState =
1630     llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 2),
1631
1632
1633
1634   // Create our type info type
1635   ourTypeInfoType = llvm::StructType::get(context,
1636                                           TypeArray(builder.getInt32Ty()));
1637
1638   llvm::Type *caughtResultFieldTypes[] = {
1639     builder.getInt8PtrTy(),
1640     builder.getInt32Ty()
1641   };
1642
1643   // Create our landingpad result type
1644   ourCaughtResultType = llvm::StructType::get(context,
1645                                             TypeArray(caughtResultFieldTypes));
1646
1647   // Create OurException type
1648   ourExceptionType = llvm::StructType::get(context,
1649                                            TypeArray(ourTypeInfoType));
1650
1651   // Create portion of _Unwind_Exception type
1652   //
1653   // Note: Declaring only a portion of the _Unwind_Exception struct.
1654   //       Does this cause problems?
1655   ourUnwindExceptionType =
1656     llvm::StructType::get(context,
1657                     TypeArray(builder.getInt64Ty()));
1658
1659   struct OurBaseException_t dummyException;
1660
1661   // Calculate offset of OurException::unwindException member.
1662   ourBaseFromUnwindOffset = ((uintptr_t) &dummyException) -
1663                             ((uintptr_t) &(dummyException.unwindException));
1664
1665 #ifdef DEBUG
1666   fprintf(stderr,
1667           "createStandardUtilityFunctions(...):ourBaseFromUnwindOffset "
1668           "= %lld, sizeof(struct OurBaseException_t) - "
1669           "sizeof(struct _Unwind_Exception) = %lu.\n",
1670           ourBaseFromUnwindOffset,
1671           sizeof(struct OurBaseException_t) -
1672           sizeof(struct _Unwind_Exception));
1673 #endif
1674
1675   size_t numChars = sizeof(ourBaseExcpClassChars) / sizeof(char);
1676
1677   // Create our _Unwind_Exception::exception_class value
1678   ourBaseExceptionClass = genClass(ourBaseExcpClassChars, numChars);
1679
1680   // Type infos
1681
1682   std::string baseStr = "typeInfo", typeInfoName;
1683   std::ostringstream typeInfoNameBuilder;
1684   std::vector<llvm::Constant*> structVals;
1685
1686   llvm::Constant *nextStruct;
1687
1688   // Generate each type info
1689   //
1690   // Note: First type info is not used.
1691   for (unsigned i = 0; i <= numTypeInfos; ++i) {
1692     structVals.clear();
1693     structVals.push_back(llvm::ConstantInt::get(builder.getInt32Ty(), i));
1694     nextStruct = llvm::ConstantStruct::get(ourTypeInfoType, structVals);
1695
1696     typeInfoNameBuilder.str("");
1697     typeInfoNameBuilder << baseStr << i;
1698     typeInfoName = typeInfoNameBuilder.str();
1699
1700     // Note: Does not seem to work without allocation
1701     new llvm::GlobalVariable(module,
1702                              ourTypeInfoType,
1703                              true,
1704                              llvm::GlobalValue::ExternalLinkage,
1705                              nextStruct,
1706                              typeInfoName);
1707
1708     ourTypeInfoNames.push_back(typeInfoName);
1709     ourTypeInfoNamesIndex[i] = typeInfoName;
1710   }
1711
1712   ArgNames argNames;
1713   ArgTypes argTypes;
1714   llvm::Function *funct = NULL;
1715
1716   // print32Int
1717
1718   llvm::Type *retType = builder.getVoidTy();
1719
1720   argTypes.clear();
1721   argTypes.push_back(builder.getInt32Ty());
1722   argTypes.push_back(builder.getInt8PtrTy());
1723
1724   argNames.clear();
1725
1726   createFunction(module,
1727                  retType,
1728                  argTypes,
1729                  argNames,
1730                  "print32Int",
1731                  llvm::Function::ExternalLinkage,
1732                  true,
1733                  false);
1734
1735   // print64Int
1736
1737   retType = builder.getVoidTy();
1738
1739   argTypes.clear();
1740   argTypes.push_back(builder.getInt64Ty());
1741   argTypes.push_back(builder.getInt8PtrTy());
1742
1743   argNames.clear();
1744
1745   createFunction(module,
1746                  retType,
1747                  argTypes,
1748                  argNames,
1749                  "print64Int",
1750                  llvm::Function::ExternalLinkage,
1751                  true,
1752                  false);
1753
1754   // printStr
1755
1756   retType = builder.getVoidTy();
1757
1758   argTypes.clear();
1759   argTypes.push_back(builder.getInt8PtrTy());
1760
1761   argNames.clear();
1762
1763   createFunction(module,
1764                  retType,
1765                  argTypes,
1766                  argNames,
1767                  "printStr",
1768                  llvm::Function::ExternalLinkage,
1769                  true,
1770                  false);
1771
1772   // throwCppException
1773
1774   retType = builder.getVoidTy();
1775
1776   argTypes.clear();
1777   argTypes.push_back(builder.getInt32Ty());
1778
1779   argNames.clear();
1780
1781   createFunction(module,
1782                  retType,
1783                  argTypes,
1784                  argNames,
1785                  "throwCppException",
1786                  llvm::Function::ExternalLinkage,
1787                  true,
1788                  false);
1789
1790   // deleteOurException
1791
1792   retType = builder.getVoidTy();
1793
1794   argTypes.clear();
1795   argTypes.push_back(builder.getInt8PtrTy());
1796
1797   argNames.clear();
1798
1799   createFunction(module,
1800                  retType,
1801                  argTypes,
1802                  argNames,
1803                  "deleteOurException",
1804                  llvm::Function::ExternalLinkage,
1805                  true,
1806                  false);
1807
1808   // createOurException
1809
1810   retType = builder.getInt8PtrTy();
1811
1812   argTypes.clear();
1813   argTypes.push_back(builder.getInt32Ty());
1814
1815   argNames.clear();
1816
1817   createFunction(module,
1818                  retType,
1819                  argTypes,
1820                  argNames,
1821                  "createOurException",
1822                  llvm::Function::ExternalLinkage,
1823                  true,
1824                  false);
1825
1826   // _Unwind_RaiseException
1827
1828   retType = builder.getInt32Ty();
1829
1830   argTypes.clear();
1831   argTypes.push_back(builder.getInt8PtrTy());
1832
1833   argNames.clear();
1834
1835   funct = createFunction(module,
1836                          retType,
1837                          argTypes,
1838                          argNames,
1839                          "_Unwind_RaiseException",
1840                          llvm::Function::ExternalLinkage,
1841                          true,
1842                          false);
1843
1844   funct->setDoesNotReturn();
1845
1846   // _Unwind_Resume
1847
1848   retType = builder.getInt32Ty();
1849
1850   argTypes.clear();
1851   argTypes.push_back(builder.getInt8PtrTy());
1852
1853   argNames.clear();
1854
1855   funct = createFunction(module,
1856                          retType,
1857                          argTypes,
1858                          argNames,
1859                          "_Unwind_Resume",
1860                          llvm::Function::ExternalLinkage,
1861                          true,
1862                          false);
1863
1864   funct->setDoesNotReturn();
1865
1866   // ourPersonality
1867
1868   retType = builder.getInt32Ty();
1869
1870   argTypes.clear();
1871   argTypes.push_back(builder.getInt32Ty());
1872   argTypes.push_back(builder.getInt32Ty());
1873   argTypes.push_back(builder.getInt64Ty());
1874   argTypes.push_back(builder.getInt8PtrTy());
1875   argTypes.push_back(builder.getInt8PtrTy());
1876
1877   argNames.clear();
1878
1879   createFunction(module,
1880                  retType,
1881                  argTypes,
1882                  argNames,
1883                  "ourPersonality",
1884                  llvm::Function::ExternalLinkage,
1885                  true,
1886                  false);
1887
1888   // llvm.eh.typeid.for intrinsic
1889
1890   getDeclaration(&module, llvm::Intrinsic::eh_typeid_for);
1891 }
1892
1893
1894 //===----------------------------------------------------------------------===//
1895 // Main test driver code.
1896 //===----------------------------------------------------------------------===//
1897
1898 /// Demo main routine which takes the type info types to throw. A test will
1899 /// be run for each given type info type. While type info types with the value
1900 /// of -1 will trigger a foreign C++ exception to be thrown; type info types
1901 /// <= 6 and >= 1 will be caught by test functions; and type info types > 6
1902 /// will result in exceptions which pass through to the test harness. All other
1903 /// type info types are not supported and could cause a crash.
1904 int main(int argc, char *argv[]) {
1905   if (argc == 1) {
1906     fprintf(stderr,
1907             "\nUsage: ExceptionDemo <exception type to throw> "
1908             "[<type 2>...<type n>].\n"
1909             "   Each type must have the value of 1 - 6 for "
1910             "generated exceptions to be caught;\n"
1911             "   the value -1 for foreign C++ exceptions to be "
1912             "generated and thrown;\n"
1913             "   or the values > 6 for exceptions to be ignored.\n"
1914             "\nTry: ExceptionDemo 2 3 7 -1\n"
1915             "   for a full test.\n\n");
1916     return(0);
1917   }
1918
1919   // If not set, exception handling will not be turned on
1920   llvm::TargetOptions Opts;
1921   Opts.JITExceptionHandling = true;
1922
1923   llvm::InitializeNativeTarget();
1924   llvm::LLVMContext &context = llvm::getGlobalContext();
1925   llvm::IRBuilder<> theBuilder(context);
1926
1927   // Make the module, which holds all the code.
1928   llvm::Module *module = new llvm::Module("my cool jit", context);
1929
1930   // Build engine with JIT
1931   llvm::EngineBuilder factory(module);
1932   factory.setEngineKind(llvm::EngineKind::JIT);
1933   factory.setAllocateGVsWithCode(false);
1934   factory.setTargetOptions(Opts);
1935   llvm::ExecutionEngine *executionEngine = factory.create();
1936
1937   {
1938     llvm::FunctionPassManager fpm(module);
1939
1940     // Set up the optimizer pipeline.
1941     // Start with registering info about how the
1942     // target lays out data structures.
1943     fpm.add(new llvm::DataLayout(*executionEngine->getDataLayout()));
1944
1945     // Optimizations turned on
1946 #ifdef ADD_OPT_PASSES
1947
1948     // Basic AliasAnslysis support for GVN.
1949     fpm.add(llvm::createBasicAliasAnalysisPass());
1950
1951     // Promote allocas to registers.
1952     fpm.add(llvm::createPromoteMemoryToRegisterPass());
1953
1954     // Do simple "peephole" optimizations and bit-twiddling optzns.
1955     fpm.add(llvm::createInstructionCombiningPass());
1956
1957     // Reassociate expressions.
1958     fpm.add(llvm::createReassociatePass());
1959
1960     // Eliminate Common SubExpressions.
1961     fpm.add(llvm::createGVNPass());
1962
1963     // Simplify the control flow graph (deleting unreachable
1964     // blocks, etc).
1965     fpm.add(llvm::createCFGSimplificationPass());
1966 #endif  // ADD_OPT_PASSES
1967
1968     fpm.doInitialization();
1969
1970     // Generate test code using function throwCppException(...) as
1971     // the function which throws foreign exceptions.
1972     llvm::Function *toRun =
1973     createUnwindExceptionTest(*module,
1974                               theBuilder,
1975                               fpm,
1976                               "throwCppException");
1977
1978     fprintf(stderr, "\nBegin module dump:\n\n");
1979
1980     module->dump();
1981
1982     fprintf(stderr, "\nEnd module dump:\n");
1983
1984     fprintf(stderr, "\n\nBegin Test:\n");
1985
1986     for (int i = 1; i < argc; ++i) {
1987       // Run test for each argument whose value is the exception
1988       // type to throw.
1989       runExceptionThrow(executionEngine,
1990                         toRun,
1991                         (unsigned) strtoul(argv[i], NULL, 10));
1992     }
1993
1994     fprintf(stderr, "\nEnd Test:\n\n");
1995   }
1996
1997   delete executionEngine;
1998
1999   return 0;
2000 }