diff options
Diffstat (limited to 'src/qml/qml/v4/qv4unwindhelper_p-arm.h')
| -rw-r--r-- | src/qml/qml/v4/qv4unwindhelper_p-arm.h | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/qml/qml/v4/qv4unwindhelper_p-arm.h b/src/qml/qml/v4/qv4unwindhelper_p-arm.h new file mode 100644 index 0000000000..ff99a0a367 --- /dev/null +++ b/src/qml/qml/v4/qv4unwindhelper_p-arm.h @@ -0,0 +1,179 @@ +#ifndef QV4UNWINDHELPER_PDW2_H +#define QV4UNWINDHELPER_PDW2_H + +#include "qv4unwindhelper_p.h" +#include "qv4functionobject_p.h" +#include "qv4function_p.h" +#include <wtf/Platform.h> + +#include <QMap> +#include <QMutex> + +#define __USE_GNU +#include <dlfcn.h> + +#if USE(LIBUNWIND_DEBUG) +#include <libunwind.h> +#include <execinfo.h> +#endif + +namespace QV4 { + +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(const 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(const QVector<Function *> &functions) +{ + QMutexLocker locker(&functionProtector); + foreach (Function *f, functions) + allFunctions.insert(reinterpret_cast<quintptr>(f->code), f); +} + +void UnwindHelper::prepareForUnwind(ExecutionContext *) +{ +} + +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(&QV4::functionProtector); + QV4::Function *function = QV4::lookupFunction(pc); + if (function) { + *entryCount = 1; + void * codeStart = QV4::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 |