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llvm-for-llvmta/examples/ExceptionDemo/ExceptionDemo.cpp

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//===-- ExceptionDemo.cpp - An example using llvm Exceptions --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Demo program which implements an example LLVM exception implementation, and
// shows several test cases including the handling of foreign exceptions.
// It is run with type info types arguments to throw. A test will
// be run for each given type info type. While type info types with the value
// of -1 will trigger a foreign C++ exception to be thrown; type info types
// <= 6 and >= 1 will cause the associated generated exceptions to be thrown
// and caught by generated test functions; and type info types > 6
// will result in exceptions which pass through to the test harness. All other
// type info types are not supported and could cause a crash. In all cases,
// the "finally" blocks of every generated test functions will executed
// regardless of whether or not that test function ignores or catches the
// thrown exception.
//
// examples:
//
// ExceptionDemo
//
// causes a usage to be printed to stderr
//
// ExceptionDemo 2 3 7 -1
//
// results in the following cases:
// - Value 2 causes an exception with a type info type of 2 to be
// thrown and caught by an inner generated test function.
// - Value 3 causes an exception with a type info type of 3 to be
// thrown and caught by an outer generated test function.
// - Value 7 causes an exception with a type info type of 7 to be
// thrown and NOT be caught by any generated function.
// - Value -1 causes a foreign C++ exception to be thrown and not be
// caught by any generated function
//
// Cases -1 and 7 are caught by a C++ test harness where the validity of
// of a C++ catch(...) clause catching a generated exception with a
// type info type of 7 is explained by: example in rules 1.6.4 in
// http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html (v1.22)
//
// This code uses code from the llvm compiler-rt project and the llvm
// Kaleidoscope project.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/STLExtras.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/ExecutionEngine/MCJIT.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Scalar.h"
// FIXME: Although all systems tested with (Linux, OS X), do not need this
// header file included. A user on ubuntu reported, undefined symbols
// for stderr, and fprintf, and the addition of this include fixed the
// issue for them. Given that LLVM's best practices include the goal
// of reducing the number of redundant header files included, the
// correct solution would be to find out why these symbols are not
// defined for the system in question, and fix the issue by finding out
// which LLVM header file, if any, would include these symbols.
#include <cstdio>
#include <sstream>
#include <stdexcept>
#include <inttypes.h>
#include <unwind.h>
#ifndef USE_GLOBAL_STR_CONSTS
#define USE_GLOBAL_STR_CONSTS true
#endif
//
// Example types
//
/// This is our simplistic type info
struct OurExceptionType_t {
/// type info type
int type;
};
/// This is our Exception class which relies on a negative offset to calculate
/// pointers to its instances from pointers to its unwindException member.
///
/// Note: The above unwind.h defines struct _Unwind_Exception to be aligned
/// on a double word boundary. This is necessary to match the standard:
/// http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html
struct OurBaseException_t {
struct OurExceptionType_t type;
// Note: This is properly aligned in unwind.h
struct _Unwind_Exception unwindException;
};
// Note: Not needed since we are C++
typedef struct OurBaseException_t OurException;
typedef struct _Unwind_Exception OurUnwindException;
//
// Various globals used to support typeinfo and generatted exceptions in
// general
//
static std::map<std::string, llvm::Value*> namedValues;
int64_t ourBaseFromUnwindOffset;
const unsigned char ourBaseExcpClassChars[] =
{'o', 'b', 'j', '\0', 'b', 'a', 's', '\0'};
static uint64_t ourBaseExceptionClass = 0;
static std::vector<std::string> ourTypeInfoNames;
static std::map<int, std::string> ourTypeInfoNamesIndex;
static llvm::StructType *ourTypeInfoType;
static llvm::StructType *ourCaughtResultType;
static llvm::StructType *ourExceptionType;
static llvm::StructType *ourUnwindExceptionType;
static llvm::ConstantInt *ourExceptionNotThrownState;
static llvm::ConstantInt *ourExceptionThrownState;
static llvm::ConstantInt *ourExceptionCaughtState;
typedef std::vector<std::string> ArgNames;
typedef std::vector<llvm::Type*> ArgTypes;
//
// Code Generation Utilities
//
/// Utility used to create a function, both declarations and definitions
/// @param module for module instance
/// @param retType function return type
/// @param theArgTypes function's ordered argument types
/// @param theArgNames function's ordered arguments needed if use of this
/// function corresponds to a function definition. Use empty
/// aggregate for function declarations.
/// @param functName function name
/// @param linkage function linkage
/// @param declarationOnly for function declarations
/// @param isVarArg function uses vararg arguments
/// @returns function instance
llvm::Function *createFunction(llvm::Module &module,
llvm::Type *retType,
const ArgTypes &theArgTypes,
const ArgNames &theArgNames,
const std::string &functName,
llvm::GlobalValue::LinkageTypes linkage,
bool declarationOnly,
bool isVarArg) {
llvm::FunctionType *functType =
llvm::FunctionType::get(retType, theArgTypes, isVarArg);
llvm::Function *ret =
llvm::Function::Create(functType, linkage, functName, &module);
if (!ret || declarationOnly)
return(ret);
namedValues.clear();
unsigned i = 0;
for (llvm::Function::arg_iterator argIndex = ret->arg_begin();
i != theArgNames.size();
++argIndex, ++i) {
argIndex->setName(theArgNames[i]);
namedValues[theArgNames[i]] = argIndex;
}
return(ret);
}
/// Create an alloca instruction in the entry block of
/// the parent function. This is used for mutable variables etc.
/// @param function parent instance
/// @param varName stack variable name
/// @param type stack variable type
/// @param initWith optional constant initialization value
/// @returns AllocaInst instance
static llvm::AllocaInst *createEntryBlockAlloca(llvm::Function &function,
const std::string &varName,
llvm::Type *type,
llvm::Constant *initWith = 0) {
llvm::BasicBlock &block = function.getEntryBlock();
llvm::IRBuilder<> tmp(&block, block.begin());
llvm::AllocaInst *ret = tmp.CreateAlloca(type, 0, varName);
if (initWith)
tmp.CreateStore(initWith, ret);
return(ret);
}
//
// Code Generation Utilities End
//
//
// Runtime C Library functions
//
namespace {
template <typename Type_>
uintptr_t ReadType(const uint8_t *&p) {
Type_ value;
memcpy(&value, p, sizeof(Type_));
p += sizeof(Type_);
return static_cast<uintptr_t>(value);
}
}
// Note: using an extern "C" block so that static functions can be used
extern "C" {
// Note: Better ways to decide on bit width
//
/// Prints a 32 bit number, according to the format, to stderr.
/// @param intToPrint integer to print
/// @param format printf like format to use when printing
void print32Int(int intToPrint, const char *format) {
if (format) {
// Note: No NULL check
fprintf(stderr, format, intToPrint);
}
else {
// Note: No NULL check
fprintf(stderr, "::print32Int(...):NULL arg.\n");
}
}
// Note: Better ways to decide on bit width
//
/// Prints a 64 bit number, according to the format, to stderr.
/// @param intToPrint integer to print
/// @param format printf like format to use when printing
void print64Int(long int intToPrint, const char *format) {
if (format) {
// Note: No NULL check
fprintf(stderr, format, intToPrint);
}
else {
// Note: No NULL check
fprintf(stderr, "::print64Int(...):NULL arg.\n");
}
}
/// Prints a C string to stderr
/// @param toPrint string to print
void printStr(char *toPrint) {
if (toPrint) {
fprintf(stderr, "%s", toPrint);
}
else {
fprintf(stderr, "::printStr(...):NULL arg.\n");
}
}
/// Deletes the true previously allocated exception whose address
/// is calculated from the supplied OurBaseException_t::unwindException
/// member address. Handles (ignores), NULL pointers.
/// @param expToDelete exception to delete
void deleteOurException(OurUnwindException *expToDelete) {
#ifdef DEBUG
fprintf(stderr,
"deleteOurException(...).\n");
#endif
if (expToDelete &&
(expToDelete->exception_class == ourBaseExceptionClass)) {
free(((char*) expToDelete) + ourBaseFromUnwindOffset);
}
}
/// This function is the struct _Unwind_Exception API mandated delete function
/// used by foreign exception handlers when deleting our exception
/// (OurException), instances.
/// @param reason See @link http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html
/// @unlink
/// @param expToDelete exception instance to delete
void deleteFromUnwindOurException(_Unwind_Reason_Code reason,
OurUnwindException *expToDelete) {
#ifdef DEBUG
fprintf(stderr,
"deleteFromUnwindOurException(...).\n");
#endif
deleteOurException(expToDelete);
}
/// Creates (allocates on the heap), an exception (OurException instance),
/// of the supplied type info type.
/// @param type type info type
OurUnwindException *createOurException(int type) {
size_t size = sizeof(OurException);
OurException *ret = (OurException*) memset(malloc(size), 0, size);
(ret->type).type = type;
(ret->unwindException).exception_class = ourBaseExceptionClass;
(ret->unwindException).exception_cleanup = deleteFromUnwindOurException;
return(&(ret->unwindException));
}
/// Read a uleb128 encoded value and advance pointer
/// See Variable Length Data in:
/// @link http://dwarfstd.org/Dwarf3.pdf @unlink
/// @param data reference variable holding memory pointer to decode from
/// @returns decoded value
static uintptr_t readULEB128(const uint8_t **data) {
uintptr_t result = 0;
uintptr_t shift = 0;
unsigned char byte;
const uint8_t *p = *data;
do {
byte = *p++;
result |= (byte & 0x7f) << shift;
shift += 7;
}
while (byte & 0x80);
*data = p;
return result;
}
/// Read a sleb128 encoded value and advance pointer
/// See Variable Length Data in:
/// @link http://dwarfstd.org/Dwarf3.pdf @unlink
/// @param data reference variable holding memory pointer to decode from
/// @returns decoded value
static uintptr_t readSLEB128(const uint8_t **data) {
uintptr_t result = 0;
uintptr_t shift = 0;
unsigned char byte;
const uint8_t *p = *data;
do {
byte = *p++;
result |= (byte & 0x7f) << shift;
shift += 7;
}
while (byte & 0x80);
*data = p;
if ((byte & 0x40) && (shift < (sizeof(result) << 3))) {
result |= (~0 << shift);
}
return result;
}
unsigned getEncodingSize(uint8_t Encoding) {
if (Encoding == llvm::dwarf::DW_EH_PE_omit)
return 0;
switch (Encoding & 0x0F) {
case llvm::dwarf::DW_EH_PE_absptr:
return sizeof(uintptr_t);
case llvm::dwarf::DW_EH_PE_udata2:
return sizeof(uint16_t);
case llvm::dwarf::DW_EH_PE_udata4:
return sizeof(uint32_t);
case llvm::dwarf::DW_EH_PE_udata8:
return sizeof(uint64_t);
case llvm::dwarf::DW_EH_PE_sdata2:
return sizeof(int16_t);
case llvm::dwarf::DW_EH_PE_sdata4:
return sizeof(int32_t);
case llvm::dwarf::DW_EH_PE_sdata8:
return sizeof(int64_t);
default:
// not supported
abort();
}
}
/// Read a pointer encoded value and advance pointer
/// See Variable Length Data in:
/// @link http://dwarfstd.org/Dwarf3.pdf @unlink
/// @param data reference variable holding memory pointer to decode from
/// @param encoding dwarf encoding type
/// @returns decoded value
static uintptr_t readEncodedPointer(const uint8_t **data, uint8_t encoding) {
uintptr_t result = 0;
const uint8_t *p = *data;
if (encoding == llvm::dwarf::DW_EH_PE_omit)
return(result);
// first get value
switch (encoding & 0x0F) {
case llvm::dwarf::DW_EH_PE_absptr:
result = ReadType<uintptr_t>(p);
break;
case llvm::dwarf::DW_EH_PE_uleb128:
result = readULEB128(&p);
break;
// Note: This case has not been tested
case llvm::dwarf::DW_EH_PE_sleb128:
result = readSLEB128(&p);
break;
case llvm::dwarf::DW_EH_PE_udata2:
result = ReadType<uint16_t>(p);
break;
case llvm::dwarf::DW_EH_PE_udata4:
result = ReadType<uint32_t>(p);
break;
case llvm::dwarf::DW_EH_PE_udata8:
result = ReadType<uint64_t>(p);
break;
case llvm::dwarf::DW_EH_PE_sdata2:
result = ReadType<int16_t>(p);
break;
case llvm::dwarf::DW_EH_PE_sdata4:
result = ReadType<int32_t>(p);
break;
case llvm::dwarf::DW_EH_PE_sdata8:
result = ReadType<int64_t>(p);
break;
default:
// not supported
abort();
break;
}
// then add relative offset
switch (encoding & 0x70) {
case llvm::dwarf::DW_EH_PE_absptr:
// do nothing
break;
case llvm::dwarf::DW_EH_PE_pcrel:
result += (uintptr_t)(*data);
break;
case llvm::dwarf::DW_EH_PE_textrel:
case llvm::dwarf::DW_EH_PE_datarel:
case llvm::dwarf::DW_EH_PE_funcrel:
case llvm::dwarf::DW_EH_PE_aligned:
default:
// not supported
abort();
break;
}
// then apply indirection
if (encoding & llvm::dwarf::DW_EH_PE_indirect) {
result = *((uintptr_t*)result);
}
*data = p;
return result;
}
/// Deals with Dwarf actions matching our type infos
/// (OurExceptionType_t instances). Returns whether or not a dwarf emitted
/// action matches the supplied exception type. If such a match succeeds,
/// the resultAction argument will be set with > 0 index value. Only
/// corresponding llvm.eh.selector type info arguments, cleanup arguments
/// are supported. Filters are not supported.
/// See Variable Length Data in:
/// @link http://dwarfstd.org/Dwarf3.pdf @unlink
/// Also see @link http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html @unlink
/// @param resultAction reference variable which will be set with result
/// @param classInfo our array of type info pointers (to globals)
/// @param actionEntry index into above type info array or 0 (clean up).
/// We do not support filters.
/// @param exceptionClass exception class (_Unwind_Exception::exception_class)
/// of thrown exception.
/// @param exceptionObject thrown _Unwind_Exception instance.
/// @returns whether or not a type info was found. False is returned if only
/// a cleanup was found
static bool handleActionValue(int64_t *resultAction,
uint8_t TTypeEncoding,
const uint8_t *ClassInfo,
uintptr_t actionEntry,
uint64_t exceptionClass,
struct _Unwind_Exception *exceptionObject) {
bool ret = false;
if (!resultAction ||
!exceptionObject ||
(exceptionClass != ourBaseExceptionClass))
return(ret);
struct OurBaseException_t *excp = (struct OurBaseException_t*)
(((char*) exceptionObject) + ourBaseFromUnwindOffset);
struct OurExceptionType_t *excpType = &(excp->type);
int type = excpType->type;
#ifdef DEBUG
fprintf(stderr,
"handleActionValue(...): exceptionObject = <%p>, "
"excp = <%p>.\n",
(void*)exceptionObject,
(void*)excp);
#endif
const uint8_t *actionPos = (uint8_t*) actionEntry,
*tempActionPos;
int64_t typeOffset = 0,
actionOffset;
for (int i = 0; true; ++i) {
// Each emitted dwarf action corresponds to a 2 tuple of
// type info address offset, and action offset to the next
// emitted action.
typeOffset = readSLEB128(&actionPos);
tempActionPos = actionPos;
actionOffset = readSLEB128(&tempActionPos);
#ifdef DEBUG
fprintf(stderr,
"handleActionValue(...):typeOffset: <%" PRIi64 ">, "
"actionOffset: <%" PRIi64 ">.\n",
typeOffset,
actionOffset);
#endif
assert((typeOffset >= 0) &&
"handleActionValue(...):filters are not supported.");
// Note: A typeOffset == 0 implies that a cleanup llvm.eh.selector
// argument has been matched.
if (typeOffset > 0) {
#ifdef DEBUG
fprintf(stderr,
"handleActionValue(...):actionValue <%d> found.\n",
i);
#endif
unsigned EncSize = getEncodingSize(TTypeEncoding);
const uint8_t *EntryP = ClassInfo - typeOffset * EncSize;
uintptr_t P = readEncodedPointer(&EntryP, TTypeEncoding);
struct OurExceptionType_t *ThisClassInfo =
reinterpret_cast<struct OurExceptionType_t *>(P);
if (ThisClassInfo->type == type) {
*resultAction = i + 1;
ret = true;
break;
}
}
#ifdef DEBUG
fprintf(stderr,
"handleActionValue(...):actionValue not found.\n");
#endif
if (!actionOffset)
break;
actionPos += actionOffset;
}
return(ret);
}
/// Deals with the Language specific data portion of the emitted dwarf code.
/// See @link http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html @unlink
/// @param version unsupported (ignored), unwind version
/// @param lsda language specific data area
/// @param _Unwind_Action actions minimally supported unwind stage
/// (forced specifically not supported)
/// @param exceptionClass exception class (_Unwind_Exception::exception_class)
/// of thrown exception.
/// @param exceptionObject thrown _Unwind_Exception instance.
/// @param context unwind system context
/// @returns minimally supported unwinding control indicator
static _Unwind_Reason_Code handleLsda(int version, const uint8_t *lsda,
_Unwind_Action actions,
_Unwind_Exception_Class exceptionClass,
struct _Unwind_Exception *exceptionObject,
struct _Unwind_Context *context) {
_Unwind_Reason_Code ret = _URC_CONTINUE_UNWIND;
if (!lsda)
return(ret);
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...):lsda is non-zero.\n");
#endif
// Get the current instruction pointer and offset it before next
// instruction in the current frame which threw the exception.
uintptr_t pc = _Unwind_GetIP(context)-1;
// Get beginning current frame's code (as defined by the
// emitted dwarf code)
uintptr_t funcStart = _Unwind_GetRegionStart(context);
uintptr_t pcOffset = pc - funcStart;
const uint8_t *ClassInfo = NULL;
// Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding
// dwarf emission
// Parse LSDA header.
uint8_t lpStartEncoding = *lsda++;
if (lpStartEncoding != llvm::dwarf::DW_EH_PE_omit) {
readEncodedPointer(&lsda, lpStartEncoding);
}
uint8_t ttypeEncoding = *lsda++;
uintptr_t classInfoOffset;
if (ttypeEncoding != llvm::dwarf::DW_EH_PE_omit) {
// Calculate type info locations in emitted dwarf code which
// were flagged by type info arguments to llvm.eh.selector
// intrinsic
classInfoOffset = readULEB128(&lsda);
ClassInfo = lsda + classInfoOffset;
}
// Walk call-site table looking for range that
// includes current PC.
uint8_t callSiteEncoding = *lsda++;
uint32_t callSiteTableLength = readULEB128(&lsda);
const uint8_t *callSiteTableStart = lsda;
const uint8_t *callSiteTableEnd = callSiteTableStart +
callSiteTableLength;
const uint8_t *actionTableStart = callSiteTableEnd;
const uint8_t *callSitePtr = callSiteTableStart;
while (callSitePtr < callSiteTableEnd) {
uintptr_t start = readEncodedPointer(&callSitePtr,
callSiteEncoding);
uintptr_t length = readEncodedPointer(&callSitePtr,
callSiteEncoding);
uintptr_t landingPad = readEncodedPointer(&callSitePtr,
callSiteEncoding);
// Note: Action value
uintptr_t actionEntry = readULEB128(&callSitePtr);
if (exceptionClass != ourBaseExceptionClass) {
// We have been notified of a foreign exception being thrown,
// and we therefore need to execute cleanup landing pads
actionEntry = 0;
}
if (landingPad == 0) {
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...): No landing pad found.\n");
#endif
continue; // no landing pad for this entry
}
if (actionEntry) {
actionEntry += ((uintptr_t) actionTableStart) - 1;
}
else {
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...):No action table found.\n");
#endif
}
bool exceptionMatched = false;
if ((start <= pcOffset) && (pcOffset < (start + length))) {
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...): Landing pad found.\n");
#endif
int64_t actionValue = 0;
if (actionEntry) {
exceptionMatched = handleActionValue(&actionValue,
ttypeEncoding,
ClassInfo,
actionEntry,
exceptionClass,
exceptionObject);
}
if (!(actions & _UA_SEARCH_PHASE)) {
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...): installed landing pad "
"context.\n");
#endif
// Found landing pad for the PC.
// Set Instruction Pointer to so we re-enter function
// at landing pad. The landing pad is created by the
// compiler to take two parameters in registers.
_Unwind_SetGR(context,
__builtin_eh_return_data_regno(0),
(uintptr_t)exceptionObject);
// Note: this virtual register directly corresponds
// to the return of the llvm.eh.selector intrinsic
if (!actionEntry || !exceptionMatched) {
// We indicate cleanup only
_Unwind_SetGR(context,
__builtin_eh_return_data_regno(1),
0);
}
else {
// Matched type info index of llvm.eh.selector intrinsic
// passed here.
_Unwind_SetGR(context,
__builtin_eh_return_data_regno(1),
actionValue);
}
// To execute landing pad set here
_Unwind_SetIP(context, funcStart + landingPad);
ret = _URC_INSTALL_CONTEXT;
}
else if (exceptionMatched) {
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...): setting handler found.\n");
#endif
ret = _URC_HANDLER_FOUND;
}
else {
// Note: Only non-clean up handlers are marked as
// found. Otherwise the clean up handlers will be
// re-found and executed during the clean up
// phase.
#ifdef DEBUG
fprintf(stderr,
"handleLsda(...): cleanup handler found.\n");
#endif
}
break;
}
}
return(ret);
}
/// This is the personality function which is embedded (dwarf emitted), in the
/// dwarf unwind info block. Again see: JITDwarfEmitter.cpp.
/// See @link http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html @unlink
/// @param version unsupported (ignored), unwind version
/// @param _Unwind_Action actions minimally supported unwind stage
/// (forced specifically not supported)
/// @param exceptionClass exception class (_Unwind_Exception::exception_class)
/// of thrown exception.
/// @param exceptionObject thrown _Unwind_Exception instance.
/// @param context unwind system context
/// @returns minimally supported unwinding control indicator
_Unwind_Reason_Code ourPersonality(int version, _Unwind_Action actions,
_Unwind_Exception_Class exceptionClass,
struct _Unwind_Exception *exceptionObject,
struct _Unwind_Context *context) {
#ifdef DEBUG
fprintf(stderr,
"We are in ourPersonality(...):actions is <%d>.\n",
actions);
if (actions & _UA_SEARCH_PHASE) {
fprintf(stderr, "ourPersonality(...):In search phase.\n");
}
else {
fprintf(stderr, "ourPersonality(...):In non-search phase.\n");
}
#endif
const uint8_t *lsda = (const uint8_t *)_Unwind_GetLanguageSpecificData(context);
#ifdef DEBUG
fprintf(stderr,
"ourPersonality(...):lsda = <%p>.\n",
(void*)lsda);
#endif
// The real work of the personality function is captured here
return(handleLsda(version,
lsda,
actions,
exceptionClass,
exceptionObject,
context));
}
/// Generates our _Unwind_Exception class from a given character array.
/// thereby handling arbitrary lengths (not in standard), and handling
/// embedded \0s.
/// See @link http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html @unlink
/// @param classChars char array to encode. NULL values not checkedf
/// @param classCharsSize number of chars in classChars. Value is not checked.
/// @returns class value
uint64_t genClass(const unsigned char classChars[], size_t classCharsSize)
{
uint64_t ret = classChars[0];
for (unsigned i = 1; i < classCharsSize; ++i) {
ret <<= 8;
ret += classChars[i];
}
return(ret);
}
} // extern "C"
//
// Runtime C Library functions End
//
//
// Code generation functions
//
/// Generates code to print given constant string
/// @param context llvm context
/// @param module code for module instance
/// @param builder builder instance
/// @param toPrint string to print
/// @param useGlobal A value of true (default) indicates a GlobalValue is
/// generated, and is used to hold the constant string. A value of
/// false indicates that the constant string will be stored on the
/// stack.
void generateStringPrint(llvm::LLVMContext &context,
llvm::Module &module,
llvm::IRBuilder<> &builder,
std::string toPrint,
bool useGlobal = true) {
llvm::Function *printFunct = module.getFunction("printStr");
llvm::Value *stringVar;
llvm::Constant *stringConstant =
llvm::ConstantDataArray::getString(context, toPrint);
if (useGlobal) {
// Note: Does not work without allocation
stringVar =
new llvm::GlobalVariable(module,
stringConstant->getType(),
true,
llvm::GlobalValue::PrivateLinkage,
stringConstant,
"");
}
else {
stringVar = builder.CreateAlloca(stringConstant->getType());
builder.CreateStore(stringConstant, stringVar);
}
llvm::Value *cast = builder.CreatePointerCast(stringVar,
builder.getInt8PtrTy());
builder.CreateCall(printFunct, cast);
}
/// Generates code to print given runtime integer according to constant
/// string format, and a given print function.
/// @param context llvm context
/// @param module code for module instance
/// @param builder builder instance
/// @param printFunct function used to "print" integer
/// @param toPrint string to print
/// @param format printf like formating string for print
/// @param useGlobal A value of true (default) indicates a GlobalValue is
/// generated, and is used to hold the constant string. A value of
/// false indicates that the constant string will be stored on the
/// stack.
void generateIntegerPrint(llvm::LLVMContext &context,
llvm::Module &module,
llvm::IRBuilder<> &builder,
llvm::Function &printFunct,
llvm::Value &toPrint,
std::string format,
bool useGlobal = true) {
llvm::Constant *stringConstant =
llvm::ConstantDataArray::getString(context, format);
llvm::Value *stringVar;
if (useGlobal) {
// Note: Does not seem to work without allocation
stringVar =
new llvm::GlobalVariable(module,
stringConstant->getType(),
true,
llvm::GlobalValue::PrivateLinkage,
stringConstant,
"");
}
else {
stringVar = builder.CreateAlloca(stringConstant->getType());
builder.CreateStore(stringConstant, stringVar);
}
llvm::Value *cast = builder.CreateBitCast(stringVar,
builder.getInt8PtrTy());
builder.CreateCall(&printFunct, {&toPrint, cast});
}
/// Generates code to handle finally block type semantics: always runs
/// regardless of whether a thrown exception is passing through or the
/// parent function is simply exiting. In addition to printing some state
/// to stderr, this code will resume the exception handling--runs the
/// unwind resume block, if the exception has not been previously caught
/// by a catch clause, and will otherwise execute the end block (terminator
/// block). In addition this function creates the corresponding function's
/// stack storage for the exception pointer and catch flag status.
/// @param context llvm context
/// @param module code for module instance
/// @param builder builder instance
/// @param toAddTo parent function to add block to
/// @param blockName block name of new "finally" block.
/// @param functionId output id used for printing
/// @param terminatorBlock terminator "end" block
/// @param unwindResumeBlock unwind resume block
/// @param exceptionCaughtFlag reference exception caught/thrown status storage
/// @param exceptionStorage reference to exception pointer storage
/// @param caughtResultStorage reference to landingpad result storage
/// @returns newly created block
static llvm::BasicBlock *createFinallyBlock(llvm::LLVMContext &context,
llvm::Module &module,
llvm::IRBuilder<> &builder,
llvm::Function &toAddTo,
std::string &blockName,
std::string &functionId,
llvm::BasicBlock &terminatorBlock,
llvm::BasicBlock &unwindResumeBlock,
llvm::Value **exceptionCaughtFlag,
llvm::Value **exceptionStorage,
llvm::Value **caughtResultStorage) {
assert(exceptionCaughtFlag &&
"ExceptionDemo::createFinallyBlock(...):exceptionCaughtFlag "
"is NULL");
assert(exceptionStorage &&
"ExceptionDemo::createFinallyBlock(...):exceptionStorage "
"is NULL");
assert(caughtResultStorage &&
"ExceptionDemo::createFinallyBlock(...):caughtResultStorage "
"is NULL");
*exceptionCaughtFlag = createEntryBlockAlloca(toAddTo,
"exceptionCaught",
ourExceptionNotThrownState->getType(),
ourExceptionNotThrownState);
llvm::PointerType *exceptionStorageType = builder.getInt8PtrTy();
*exceptionStorage = createEntryBlockAlloca(toAddTo,
"exceptionStorage",
exceptionStorageType,
llvm::ConstantPointerNull::get(
exceptionStorageType));
*caughtResultStorage = createEntryBlockAlloca(toAddTo,
"caughtResultStorage",
ourCaughtResultType,
llvm::ConstantAggregateZero::get(
ourCaughtResultType));
llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
blockName,
&toAddTo);
builder.SetInsertPoint(ret);
std::ostringstream bufferToPrint;
bufferToPrint << "Gen: Executing finally block "
<< blockName << " in " << functionId << "\n";
generateStringPrint(context,
module,
builder,
bufferToPrint.str(),
USE_GLOBAL_STR_CONSTS);
llvm::SwitchInst *theSwitch = builder.CreateSwitch(builder.CreateLoad(
*exceptionCaughtFlag),
&terminatorBlock,
2);
theSwitch->addCase(ourExceptionCaughtState, &terminatorBlock);
theSwitch->addCase(ourExceptionThrownState, &unwindResumeBlock);
return(ret);
}
/// Generates catch block semantics which print a string to indicate type of
/// catch executed, sets an exception caught flag, and executes passed in
/// end block (terminator block).
/// @param context llvm context
/// @param module code for module instance
/// @param builder builder instance
/// @param toAddTo parent function to add block to
/// @param blockName block name of new "catch" block.
/// @param functionId output id used for printing
/// @param terminatorBlock terminator "end" block
/// @param exceptionCaughtFlag exception caught/thrown status
/// @returns newly created block
static llvm::BasicBlock *createCatchBlock(llvm::LLVMContext &context,
llvm::Module &module,
llvm::IRBuilder<> &builder,
llvm::Function &toAddTo,
std::string &blockName,
std::string &functionId,
llvm::BasicBlock &terminatorBlock,
llvm::Value &exceptionCaughtFlag) {
llvm::BasicBlock *ret = llvm::BasicBlock::Create(context,
blockName,
&toAddTo);
builder.SetInsertPoint(ret);
std::ostringstream bufferToPrint;
bufferToPrint << "Gen: Executing catch block "
<< blockName
<< " in "
<< functionId
<< std::endl;
generateStringPrint(context,
module,
builder,
bufferToPrint.str(),
USE_GLOBAL_STR_CONSTS);
builder.CreateStore(ourExceptionCaughtState, &exceptionCaughtFlag);
builder.CreateBr(&terminatorBlock);
return(ret);
}
/// Generates a function which invokes a function (toInvoke) and, whose
/// unwind block will "catch" the type info types correspondingly held in the
/// exceptionTypesToCatch argument. If the toInvoke function throws an
/// exception which does not match any type info types contained in
/// exceptionTypesToCatch, the generated code will call _Unwind_Resume
/// with the raised exception. On the other hand the generated code will
/// normally exit if the toInvoke function does not throw an exception.
/// The generated "finally" block is always run regardless of the cause of
/// the generated function exit.
/// The generated function is returned after being verified.
/// @param module code for module instance
/// @param builder builder instance
/// @param fpm a function pass manager holding optional IR to IR
/// transformations
/// @param toInvoke inner function to invoke
/// @param ourId id used to printing purposes
/// @param numExceptionsToCatch length of exceptionTypesToCatch array
/// @param exceptionTypesToCatch array of type info types to "catch"
/// @returns generated function
static llvm::Function *createCatchWrappedInvokeFunction(
llvm::Module &module, llvm::IRBuilder<> &builder,
llvm::legacy::FunctionPassManager &fpm, llvm::Function &toInvoke,
std::string ourId, unsigned numExceptionsToCatch,
unsigned exceptionTypesToCatch[]) {
llvm::LLVMContext &context = module.getContext();
llvm::Function *toPrint32Int = module.getFunction("print32Int");
ArgTypes argTypes;
argTypes.push_back(builder.getInt32Ty());
ArgNames argNames;
argNames.push_back("exceptTypeToThrow");
llvm::Function *ret = createFunction(module,
builder.getVoidTy(),
argTypes,
argNames,
ourId,
llvm::Function::ExternalLinkage,
false,
false);
// Block which calls invoke
llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
"entry",
ret);
// Normal block for invoke
llvm::BasicBlock *normalBlock = llvm::BasicBlock::Create(context,
"normal",
ret);
// Unwind block for invoke
llvm::BasicBlock *exceptionBlock = llvm::BasicBlock::Create(context,
"exception",
ret);
// Block which routes exception to correct catch handler block
llvm::BasicBlock *exceptionRouteBlock = llvm::BasicBlock::Create(context,
"exceptionRoute",
ret);
// Foreign exception handler
llvm::BasicBlock *externalExceptionBlock = llvm::BasicBlock::Create(context,
"externalException",
ret);
// Block which calls _Unwind_Resume
llvm::BasicBlock *unwindResumeBlock = llvm::BasicBlock::Create(context,
"unwindResume",
ret);
// Clean up block which delete exception if needed
llvm::BasicBlock *endBlock = llvm::BasicBlock::Create(context, "end", ret);
std::string nextName;
std::vector<llvm::BasicBlock*> catchBlocks(numExceptionsToCatch);
llvm::Value *exceptionCaughtFlag = NULL;
llvm::Value *exceptionStorage = NULL;
llvm::Value *caughtResultStorage = NULL;
// Finally block which will branch to unwindResumeBlock if
// exception is not caught. Initializes/allocates stack locations.
llvm::BasicBlock *finallyBlock = createFinallyBlock(context,
module,
builder,
*ret,
nextName = "finally",
ourId,
*endBlock,
*unwindResumeBlock,
&exceptionCaughtFlag,
&exceptionStorage,
&caughtResultStorage
);
for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
nextName = ourTypeInfoNames[exceptionTypesToCatch[i]];
// One catch block per type info to be caught
catchBlocks[i] = createCatchBlock(context,
module,
builder,
*ret,
nextName,
ourId,
*finallyBlock,
*exceptionCaughtFlag);
}
// Entry Block
builder.SetInsertPoint(entryBlock);
std::vector<llvm::Value*> args;
args.push_back(namedValues["exceptTypeToThrow"]);
builder.CreateInvoke(&toInvoke,
normalBlock,
exceptionBlock,
args);
// End Block
builder.SetInsertPoint(endBlock);
generateStringPrint(context,
module,
builder,
"Gen: In end block: exiting in " + ourId + ".\n",
USE_GLOBAL_STR_CONSTS);
llvm::Function *deleteOurException = module.getFunction("deleteOurException");
// Note: function handles NULL exceptions
builder.CreateCall(deleteOurException,
builder.CreateLoad(exceptionStorage));
builder.CreateRetVoid();
// Normal Block
builder.SetInsertPoint(normalBlock);
generateStringPrint(context,
module,
builder,
"Gen: No exception in " + ourId + "!\n",
USE_GLOBAL_STR_CONSTS);
// Finally block is always called
builder.CreateBr(finallyBlock);
// Unwind Resume Block
builder.SetInsertPoint(unwindResumeBlock);
builder.CreateResume(builder.CreateLoad(caughtResultStorage));
// Exception Block
builder.SetInsertPoint(exceptionBlock);
llvm::Function *personality = module.getFunction("ourPersonality");
ret->setPersonalityFn(personality);
llvm::LandingPadInst *caughtResult =
builder.CreateLandingPad(ourCaughtResultType,
numExceptionsToCatch,
"landingPad");
caughtResult->setCleanup(true);
for (unsigned i = 0; i < numExceptionsToCatch; ++i) {
// Set up type infos to be caught
caughtResult->addClause(module.getGlobalVariable(
ourTypeInfoNames[exceptionTypesToCatch[i]]));
}
llvm::Value *unwindException = builder.CreateExtractValue(caughtResult, 0);
llvm::Value *retTypeInfoIndex = builder.CreateExtractValue(caughtResult, 1);
// FIXME: Redundant storage which, beyond utilizing value of
// caughtResultStore for unwindException storage, may be alleviated
// altogether with a block rearrangement
builder.CreateStore(caughtResult, caughtResultStorage);
builder.CreateStore(unwindException, exceptionStorage);
builder.CreateStore(ourExceptionThrownState, exceptionCaughtFlag);
// Retrieve exception_class member from thrown exception
// (_Unwind_Exception instance). This member tells us whether or not
// the exception is foreign.
llvm::Value *unwindExceptionClass =
builder.CreateLoad(builder.CreateStructGEP(
ourUnwindExceptionType,
builder.CreatePointerCast(unwindException,
ourUnwindExceptionType->getPointerTo()),
0));
// Branch to the externalExceptionBlock if the exception is foreign or
// to a catch router if not. Either way the finally block will be run.
builder.CreateCondBr(builder.CreateICmpEQ(unwindExceptionClass,
llvm::ConstantInt::get(builder.getInt64Ty(),
ourBaseExceptionClass)),
exceptionRouteBlock,
externalExceptionBlock);
// External Exception Block
builder.SetInsertPoint(externalExceptionBlock);
generateStringPrint(context,
module,
builder,
"Gen: Foreign exception received.\n",
USE_GLOBAL_STR_CONSTS);
// Branch to the finally block
builder.CreateBr(finallyBlock);
// Exception Route Block
builder.SetInsertPoint(exceptionRouteBlock);
// Casts exception pointer (_Unwind_Exception instance) to parent
// (OurException instance).
//
// Note: ourBaseFromUnwindOffset is usually negative
llvm::Value *typeInfoThrown = builder.CreatePointerCast(
builder.CreateConstGEP1_64(unwindException,
ourBaseFromUnwindOffset),
ourExceptionType->getPointerTo());
// Retrieve thrown exception type info type
//
// Note: Index is not relative to pointer but instead to structure
// unlike a true getelementptr (GEP) instruction
typeInfoThrown = builder.CreateStructGEP(ourExceptionType, typeInfoThrown, 0);
llvm::Value *typeInfoThrownType =
builder.CreateStructGEP(builder.getInt8PtrTy(), typeInfoThrown, 0);
generateIntegerPrint(context,
module,
builder,
*toPrint32Int,
*(builder.CreateLoad(typeInfoThrownType)),
"Gen: Exception type <%d> received (stack unwound) "
" in " +
ourId +
".\n",
USE_GLOBAL_STR_CONSTS);
// Route to matched type info catch block or run cleanup finally block
llvm::SwitchInst *switchToCatchBlock = builder.CreateSwitch(retTypeInfoIndex,
finallyBlock,
numExceptionsToCatch);
unsigned nextTypeToCatch;
for (unsigned i = 1; i <= numExceptionsToCatch; ++i) {
nextTypeToCatch = i - 1;
switchToCatchBlock->addCase(llvm::ConstantInt::get(
llvm::Type::getInt32Ty(context), i),
catchBlocks[nextTypeToCatch]);
}
llvm::verifyFunction(*ret);
fpm.run(*ret);
return(ret);
}
/// Generates function which throws either an exception matched to a runtime
/// determined type info type (argument to generated function), or if this
/// runtime value matches nativeThrowType, throws a foreign exception by
/// calling nativeThrowFunct.
/// @param module code for module instance
/// @param builder builder instance
/// @param fpm a function pass manager holding optional IR to IR
/// transformations
/// @param ourId id used to printing purposes
/// @param nativeThrowType a runtime argument of this value results in
/// nativeThrowFunct being called to generate/throw exception.
/// @param nativeThrowFunct function which will throw a foreign exception
/// if the above nativeThrowType matches generated function's arg.
/// @returns generated function
static llvm::Function *
createThrowExceptionFunction(llvm::Module &module, llvm::IRBuilder<> &builder,
llvm::legacy::FunctionPassManager &fpm,
std::string ourId, int32_t nativeThrowType,
llvm::Function &nativeThrowFunct) {
llvm::LLVMContext &context = module.getContext();
namedValues.clear();
ArgTypes unwindArgTypes;
unwindArgTypes.push_back(builder.getInt32Ty());
ArgNames unwindArgNames;
unwindArgNames.push_back("exceptTypeToThrow");
llvm::Function *ret = createFunction(module,
builder.getVoidTy(),
unwindArgTypes,
unwindArgNames,
ourId,
llvm::Function::ExternalLinkage,
false,
false);
// Throws either one of our exception or a native C++ exception depending
// on a runtime argument value containing a type info type.
llvm::BasicBlock *entryBlock = llvm::BasicBlock::Create(context,
"entry",
ret);
// Throws a foreign exception
llvm::BasicBlock *nativeThrowBlock = llvm::BasicBlock::Create(context,
"nativeThrow",
ret);
// Throws one of our Exceptions
llvm::BasicBlock *generatedThrowBlock = llvm::BasicBlock::Create(context,
"generatedThrow",
ret);
// Retrieved runtime type info type to throw
llvm::Value *exceptionType = namedValues["exceptTypeToThrow"];
// nativeThrowBlock block
builder.SetInsertPoint(nativeThrowBlock);
// Throws foreign exception
builder.CreateCall(&nativeThrowFunct, exceptionType);
builder.CreateUnreachable();
// entry block
builder.SetInsertPoint(entryBlock);
llvm::Function *toPrint32Int = module.getFunction("print32Int");
generateIntegerPrint(context,
module,
builder,
*toPrint32Int,
*exceptionType,
"\nGen: About to throw exception type <%d> in " +
ourId +
".\n",
USE_GLOBAL_STR_CONSTS);
// Switches on runtime type info type value to determine whether or not
// a foreign exception is thrown. Defaults to throwing one of our
// generated exceptions.
llvm::SwitchInst *theSwitch = builder.CreateSwitch(exceptionType,
generatedThrowBlock,
1);
theSwitch->addCase(llvm::ConstantInt::get(llvm::Type::getInt32Ty(context),
nativeThrowType),
nativeThrowBlock);
// generatedThrow block
builder.SetInsertPoint(generatedThrowBlock);
llvm::Function *createOurException = module.getFunction("createOurException");
llvm::Function *raiseOurException = module.getFunction(
"_Unwind_RaiseException");
// Creates exception to throw with runtime type info type.
llvm::Value *exception = builder.CreateCall(createOurException,
namedValues["exceptTypeToThrow"]);
// Throw generated Exception
builder.CreateCall(raiseOurException, exception);
builder.CreateUnreachable();
llvm::verifyFunction(*ret);
fpm.run(*ret);
return(ret);
}
static void createStandardUtilityFunctions(unsigned numTypeInfos,
llvm::Module &module,
llvm::IRBuilder<> &builder);
/// Creates test code by generating and organizing these functions into the
/// test case. The test case consists of an outer function setup to invoke
/// an inner function within an environment having multiple catch and single
/// finally blocks. This inner function is also setup to invoke a throw
/// function within an evironment similar in nature to the outer function's
/// catch and finally blocks. Each of these two functions catch mutually
/// exclusive subsets (even or odd) of the type info types configured
/// for this this. All generated functions have a runtime argument which
/// holds a type info type to throw that each function takes and passes it
/// to the inner one if such a inner function exists. This type info type is
/// looked at by the generated throw function to see whether or not it should
/// throw a generated exception with the same type info type, or instead call
/// a supplied a function which in turn will throw a foreign exception.
/// @param module code for module instance
/// @param builder builder instance
/// @param fpm a function pass manager holding optional IR to IR
/// transformations
/// @param nativeThrowFunctName name of external function which will throw
/// a foreign exception
/// @returns outermost generated test function.
llvm::Function *
createUnwindExceptionTest(llvm::Module &module, llvm::IRBuilder<> &builder,
llvm::legacy::FunctionPassManager &fpm,
std::string nativeThrowFunctName) {
// Number of type infos to generate
unsigned numTypeInfos = 6;
// Initialze intrisics and external functions to use along with exception
// and type info globals.
createStandardUtilityFunctions(numTypeInfos,
module,
builder);
llvm::Function *nativeThrowFunct = module.getFunction(nativeThrowFunctName);
// Create exception throw function using the value ~0 to cause
// foreign exceptions to be thrown.
llvm::Function *throwFunct = createThrowExceptionFunction(module,
builder,
fpm,
"throwFunct",
~0,
*nativeThrowFunct);
// Inner function will catch even type infos
unsigned innerExceptionTypesToCatch[] = {6, 2, 4};
size_t numExceptionTypesToCatch = sizeof(innerExceptionTypesToCatch) /
sizeof(unsigned);
// Generate inner function.
llvm::Function *innerCatchFunct = createCatchWrappedInvokeFunction(module,
builder,
fpm,
*throwFunct,
"innerCatchFunct",
numExceptionTypesToCatch,
innerExceptionTypesToCatch);
// Outer function will catch odd type infos
unsigned outerExceptionTypesToCatch[] = {3, 1, 5};
numExceptionTypesToCatch = sizeof(outerExceptionTypesToCatch) /
sizeof(unsigned);
// Generate outer function
llvm::Function *outerCatchFunct = createCatchWrappedInvokeFunction(module,
builder,
fpm,
*innerCatchFunct,
"outerCatchFunct",
numExceptionTypesToCatch,
outerExceptionTypesToCatch);
// Return outer function to run
return(outerCatchFunct);
}
namespace {
/// Represents our foreign exceptions
class OurCppRunException : public std::runtime_error {
public:
OurCppRunException(const std::string reason) :
std::runtime_error(reason) {}
OurCppRunException (const OurCppRunException &toCopy) :
std::runtime_error(toCopy) {}
OurCppRunException &operator = (const OurCppRunException &toCopy) {
return(reinterpret_cast<OurCppRunException&>(
std::runtime_error::operator=(toCopy)));
}
~OurCppRunException(void) throw() override {}
};
} // end anonymous namespace
/// Throws foreign C++ exception.
/// @param ignoreIt unused parameter that allows function to match implied
/// generated function contract.
extern "C"
void throwCppException (int32_t ignoreIt) {
throw(OurCppRunException("thrown by throwCppException(...)"));
}
typedef void (*OurExceptionThrowFunctType) (int32_t typeToThrow);
/// This is a test harness which runs test by executing generated
/// function with a type info type to throw. Harness wraps the execution
/// of generated function in a C++ try catch clause.
/// @param engine execution engine to use for executing generated function.
/// This demo program expects this to be a JIT instance for demo
/// purposes.
/// @param function generated test function to run
/// @param typeToThrow type info type of generated exception to throw, or
/// indicator to cause foreign exception to be thrown.
static
void runExceptionThrow(llvm::ExecutionEngine *engine,
llvm::Function *function,
int32_t typeToThrow) {
// Find test's function pointer
OurExceptionThrowFunctType functPtr =
reinterpret_cast<OurExceptionThrowFunctType>(
reinterpret_cast<intptr_t>(engine->getPointerToFunction(function)));
try {
// Run test
(*functPtr)(typeToThrow);
}
catch (OurCppRunException exc) {
// Catch foreign C++ exception
fprintf(stderr,
"\nrunExceptionThrow(...):In C++ catch OurCppRunException "
"with reason: %s.\n",
exc.what());
}
catch (...) {
// Catch all exceptions including our generated ones. This latter
// functionality works according to the example in rules 1.6.4 of
// http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html (v1.22),
// given that these will be exceptions foreign to C++
// (the _Unwind_Exception::exception_class should be different from
// the one used by C++).
fprintf(stderr,
"\nrunExceptionThrow(...):In C++ catch all.\n");
}
}
//
// End test functions
//
typedef llvm::ArrayRef<llvm::Type*> TypeArray;
/// This initialization routine creates type info globals and
/// adds external function declarations to module.
/// @param numTypeInfos number of linear type info associated type info types
/// to create as GlobalVariable instances, starting with the value 1.
/// @param module code for module instance
/// @param builder builder instance
static void createStandardUtilityFunctions(unsigned numTypeInfos,
llvm::Module &module,
llvm::IRBuilder<> &builder) {
llvm::LLVMContext &context = module.getContext();
// Exception initializations
// Setup exception catch state
ourExceptionNotThrownState =
llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 0),
ourExceptionThrownState =
llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 1),
ourExceptionCaughtState =
llvm::ConstantInt::get(llvm::Type::getInt8Ty(context), 2),
// Create our type info type
ourTypeInfoType = llvm::StructType::get(context,
TypeArray(builder.getInt32Ty()));
llvm::Type *caughtResultFieldTypes[] = {
builder.getInt8PtrTy(),
builder.getInt32Ty()
};
// Create our landingpad result type
ourCaughtResultType = llvm::StructType::get(context,
TypeArray(caughtResultFieldTypes));
// Create OurException type
ourExceptionType = llvm::StructType::get(context,
TypeArray(ourTypeInfoType));
// Create portion of _Unwind_Exception type
//
// Note: Declaring only a portion of the _Unwind_Exception struct.
// Does this cause problems?
ourUnwindExceptionType =
llvm::StructType::get(context,
TypeArray(builder.getInt64Ty()));
struct OurBaseException_t dummyException;
// Calculate offset of OurException::unwindException member.
ourBaseFromUnwindOffset = ((uintptr_t) &dummyException) -
((uintptr_t) &(dummyException.unwindException));
#ifdef DEBUG
fprintf(stderr,
"createStandardUtilityFunctions(...):ourBaseFromUnwindOffset "
"= %" PRIi64 ", sizeof(struct OurBaseException_t) - "
"sizeof(struct _Unwind_Exception) = %lu.\n",
ourBaseFromUnwindOffset,
sizeof(struct OurBaseException_t) -
sizeof(struct _Unwind_Exception));
#endif
size_t numChars = sizeof(ourBaseExcpClassChars) / sizeof(char);
// Create our _Unwind_Exception::exception_class value
ourBaseExceptionClass = genClass(ourBaseExcpClassChars, numChars);
// Type infos
std::string baseStr = "typeInfo", typeInfoName;
std::ostringstream typeInfoNameBuilder;
std::vector<llvm::Constant*> structVals;
llvm::Constant *nextStruct;
// Generate each type info
//
// Note: First type info is not used.
for (unsigned i = 0; i <= numTypeInfos; ++i) {
structVals.clear();
structVals.push_back(llvm::ConstantInt::get(builder.getInt32Ty(), i));
nextStruct = llvm::ConstantStruct::get(ourTypeInfoType, structVals);
typeInfoNameBuilder.str("");
typeInfoNameBuilder << baseStr << i;
typeInfoName = typeInfoNameBuilder.str();
// Note: Does not seem to work without allocation
new llvm::GlobalVariable(module,
ourTypeInfoType,
true,
llvm::GlobalValue::ExternalLinkage,
nextStruct,
typeInfoName);
ourTypeInfoNames.push_back(typeInfoName);
ourTypeInfoNamesIndex[i] = typeInfoName;
}
ArgNames argNames;
ArgTypes argTypes;
llvm::Function *funct = NULL;
// print32Int
llvm::Type *retType = builder.getVoidTy();
argTypes.clear();
argTypes.push_back(builder.getInt32Ty());
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"print32Int",
llvm::Function::ExternalLinkage,
true,
false);
// print64Int
retType = builder.getVoidTy();
argTypes.clear();
argTypes.push_back(builder.getInt64Ty());
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"print64Int",
llvm::Function::ExternalLinkage,
true,
false);
// printStr
retType = builder.getVoidTy();
argTypes.clear();
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"printStr",
llvm::Function::ExternalLinkage,
true,
false);
// throwCppException
retType = builder.getVoidTy();
argTypes.clear();
argTypes.push_back(builder.getInt32Ty());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"throwCppException",
llvm::Function::ExternalLinkage,
true,
false);
// deleteOurException
retType = builder.getVoidTy();
argTypes.clear();
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"deleteOurException",
llvm::Function::ExternalLinkage,
true,
false);
// createOurException
retType = builder.getInt8PtrTy();
argTypes.clear();
argTypes.push_back(builder.getInt32Ty());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"createOurException",
llvm::Function::ExternalLinkage,
true,
false);
// _Unwind_RaiseException
retType = builder.getInt32Ty();
argTypes.clear();
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
funct = createFunction(module,
retType,
argTypes,
argNames,
"_Unwind_RaiseException",
llvm::Function::ExternalLinkage,
true,
false);
funct->setDoesNotReturn();
// _Unwind_Resume
retType = builder.getInt32Ty();
argTypes.clear();
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
funct = createFunction(module,
retType,
argTypes,
argNames,
"_Unwind_Resume",
llvm::Function::ExternalLinkage,
true,
false);
funct->setDoesNotReturn();
// ourPersonality
retType = builder.getInt32Ty();
argTypes.clear();
argTypes.push_back(builder.getInt32Ty());
argTypes.push_back(builder.getInt32Ty());
argTypes.push_back(builder.getInt64Ty());
argTypes.push_back(builder.getInt8PtrTy());
argTypes.push_back(builder.getInt8PtrTy());
argNames.clear();
createFunction(module,
retType,
argTypes,
argNames,
"ourPersonality",
llvm::Function::ExternalLinkage,
true,
false);
// llvm.eh.typeid.for intrinsic
getDeclaration(&module, llvm::Intrinsic::eh_typeid_for);
}
//===----------------------------------------------------------------------===//
// Main test driver code.
//===----------------------------------------------------------------------===//
/// Demo main routine which takes the type info types to throw. A test will
/// be run for each given type info type. While type info types with the value
/// of -1 will trigger a foreign C++ exception to be thrown; type info types
/// <= 6 and >= 1 will be caught by test functions; and type info types > 6
/// will result in exceptions which pass through to the test harness. All other
/// type info types are not supported and could cause a crash.
int main(int argc, char *argv[]) {
if (argc == 1) {
fprintf(stderr,
"\nUsage: ExceptionDemo <exception type to throw> "
"[<type 2>...<type n>].\n"
" Each type must have the value of 1 - 6 for "
"generated exceptions to be caught;\n"
" the value -1 for foreign C++ exceptions to be "
"generated and thrown;\n"
" or the values > 6 for exceptions to be ignored.\n"
"\nTry: ExceptionDemo 2 3 7 -1\n"
" for a full test.\n\n");
return(0);
}
// If not set, exception handling will not be turned on
llvm::TargetOptions Opts;
llvm::InitializeNativeTarget();
llvm::InitializeNativeTargetAsmPrinter();
llvm::LLVMContext Context;
llvm::IRBuilder<> theBuilder(Context);
// Make the module, which holds all the code.
std::unique_ptr<llvm::Module> Owner =
std::make_unique<llvm::Module>("my cool jit", Context);
llvm::Module *module = Owner.get();
std::unique_ptr<llvm::RTDyldMemoryManager> MemMgr(new llvm::SectionMemoryManager());
// Build engine with JIT
llvm::EngineBuilder factory(std::move(Owner));
factory.setEngineKind(llvm::EngineKind::JIT);
factory.setTargetOptions(Opts);
factory.setMCJITMemoryManager(std::move(MemMgr));
llvm::ExecutionEngine *executionEngine = factory.create();
{
llvm::legacy::FunctionPassManager fpm(module);
// Set up the optimizer pipeline.
// Start with registering info about how the
// target lays out data structures.
module->setDataLayout(executionEngine->getDataLayout());
// Optimizations turned on
#ifdef ADD_OPT_PASSES
// Basic AliasAnslysis support for GVN.
fpm.add(llvm::createBasicAliasAnalysisPass());
// Promote allocas to registers.
fpm.add(llvm::createPromoteMemoryToRegisterPass());
// Do simple "peephole" optimizations and bit-twiddling optzns.
fpm.add(llvm::createInstructionCombiningPass());
// Reassociate expressions.
fpm.add(llvm::createReassociatePass());
// Eliminate Common SubExpressions.
fpm.add(llvm::createGVNPass());
// Simplify the control flow graph (deleting unreachable
// blocks, etc).
fpm.add(llvm::createCFGSimplificationPass());
#endif // ADD_OPT_PASSES
fpm.doInitialization();
// Generate test code using function throwCppException(...) as
// the function which throws foreign exceptions.
llvm::Function *toRun =
createUnwindExceptionTest(*module,
theBuilder,
fpm,
"throwCppException");
executionEngine->finalizeObject();
#ifndef NDEBUG
fprintf(stderr, "\nBegin module dump:\n\n");
module->dump();
fprintf(stderr, "\nEnd module dump:\n");
#endif
fprintf(stderr, "\n\nBegin Test:\n");
for (int i = 1; i < argc; ++i) {
// Run test for each argument whose value is the exception
// type to throw.
runExceptionThrow(executionEngine,
toRun,
(unsigned) strtoul(argv[i], NULL, 10));
}
fprintf(stderr, "\nEnd Test:\n\n");
}
delete executionEngine;
return 0;
}