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#ifndef QV4UNWINDHELPER_PDW2_H
#define QV4UNWINDHELPER_PDW2_H
#include "qv4unwindhelper_p.h"
#include "qv4functionobject_p.h"
#include <wtf/Platform.h>
#include <QMap>
#include <QMutex>
#define __USE_GNU
#include <dlfcn.h>
#if USE(LIBUNWIND_DEBUG)
#include <libunwind.h>
#endif
#include <execinfo.h>
namespace QQmlJS {
namespace VM {
static void *removeThumbBit(void *addr)
{
return reinterpret_cast<void*>(reinterpret_cast<intptr_t>(addr) & ~1u);
}
static QMutex functionProtector;
static QMap<quintptr, Function*> allFunctions;
static Function *lookupFunction(void *pc)
{
quintptr key = reinterpret_cast<quintptr>(pc);
QMap<quintptr, Function*>::ConstIterator it = allFunctions.lowerBound(key);
if (it != allFunctions.begin() && allFunctions.count() > 0)
--it;
if (it == allFunctions.end())
return 0;
quintptr codeStart = reinterpret_cast<quintptr>(removeThumbBit((*it)->codeRef.code().executableAddress()));
if (key < codeStart || key >= codeStart + (*it)->codeSize)
return 0;
return *it;
}
/* Program:
vsp = r4 (REG_TO_SP r4)
vsp -= 8 * 4 -- > vsp = vsp - (7 << 2) - 4
pop r12, r10, r9, r8, r7, r6, r5, r4
pop r4
pop lr
pop r0, r1, r2, r3
*/
#define REG_TO_SP 0b10010000
#define VSP_MINUS 0b01000000
#define POP_REG_MULTI 0b10000000
#define POP_R4_MULTI 0b10100000
#define POP_R4_R14_MULTI 0b10101000
#define POP_R0_TO_R3 0b10110001
#define FINISH 0b10110000
#define MK_UW_WORD(first, second, third, fourth) \
(((first) << 24) | \
((second) << 16) | \
((third) << 8) | \
(fourth))
static unsigned int extbl[] = {
MK_UW_WORD(0x80 | // High bit set to indicate that this isn't a PREL31
2, // Choose personality routine #2
2, // Number of 4 byte words used to encode remaining unwind instructions
REG_TO_SP | 4, // Encoded program from above.
VSP_MINUS | 7),
MK_UW_WORD(POP_REG_MULTI | 1, 0b01111111,
POP_R4_R14_MULTI,
POP_R0_TO_R3),
MK_UW_WORD(0b00001111,
FINISH,
FINISH,
FINISH)
};
static unsigned write_prel31(unsigned *addr, void *ptr)
{
int delta = (char *)ptr - (char*)addr;
if (delta < 0)
delta |= (1 << 30);
else
delta &= ~(1 << 30);
*addr = ((unsigned)delta) & 0x7fffffffU;
}
void UnwindHelper::deregisterFunction(Function *function)
{
QMutexLocker locker(&functionProtector);
allFunctions.remove(reinterpret_cast<quintptr>(function->code));
}
void UnwindHelper::deregisterFunctions(QVector<Function *> functions)
{
QMutexLocker locker(&functionProtector);
foreach (Function *f, functions)
allFunctions.remove(reinterpret_cast<quintptr>(f->code));
}
void UnwindHelper::registerFunction(Function *function)
{
QMutexLocker locker(&functionProtector);
allFunctions.insert(reinterpret_cast<quintptr>(function->code), function);
}
void UnwindHelper::registerFunctions(QVector<Function *> functions)
{
QMutexLocker locker(&functionProtector);
foreach (Function *f, functions)
allFunctions.insert(reinterpret_cast<quintptr>(f->code), f);
}
int UnwindHelper::unwindInfoSize()
{
return 2 * sizeof(unsigned int) // 2 extbl entries
+ sizeof(extbl);
}
void UnwindHelper::writeARMUnwindInfo(void *codeAddr, int codeSize)
{
unsigned int *exidx = (unsigned int *)((char *)codeAddr + codeSize);
unsigned char *exprog = (unsigned char *)((unsigned char *)codeAddr + codeSize + 8);
write_prel31(exidx, codeAddr);
exidx[1] = 4; // PREL31 offset to extbl, which follows right afterwards
memcpy(exprog, extbl, sizeof(extbl));
#if USE(LIBUNWIND_DEBUG)
unw_dyn_info_t *info = (unw_dyn_info_t*)malloc(sizeof(unw_dyn_info_t));
info->start_ip = (unw_word_t)codeAddr;
info->end_ip = info->start_ip + codeSize;
info->gp = 0;
info->format = UNW_INFO_FORMAT_ARM_EXIDX;
info->u.rti.name_ptr = 0;
info->u.rti.segbase = 0;
info->u.rti.table_len = 8;
info->u.rti.table_data = (unw_word_t)exidx;
_U_dyn_register(info);
#endif
}
}
}
extern "C" Q_DECL_EXPORT void *__gnu_Unwind_Find_exidx(void *pc, int *entryCount)
{
typedef void *(*Old_Unwind_Find_exidx)(void*, int*);
static Old_Unwind_Find_exidx oldFunction = 0;
static ptrdiff_t *exidx = (ptrdiff_t*)malloc(2 * sizeof(uintptr_t));
if (!oldFunction)
oldFunction = (Old_Unwind_Find_exidx)dlsym(RTLD_NEXT, "__gnu_Unwind_Find_exidx");
{
QMutexLocker locker(&QQmlJS::VM::functionProtector);
QQmlJS::VM::Function *function = QQmlJS::VM::lookupFunction(pc);
if (function) {
*entryCount = 1;
void * codeStart = QQmlJS::VM::removeThumbBit(function->codeRef.code().executableAddress());
// At the end of the function we store our synthetic exception table entry.
return (char *)codeStart + function->codeSize;
}
}
return oldFunction(pc, entryCount);
}
#endif // QV4UNWINDHELPER_PDW2_H
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