[cfe-commits] [libcxxabi] r147761 - /libcxxabi/trunk/src/cxa_personality.cpp
Howard Hinnant
hhinnant at apple.com
Sun Jan 8 15:50:46 PST 2012
Author: hhinnant
Date: Sun Jan 8 17:50:46 2012
New Revision: 147761
URL: http://llvm.org/viewvc/llvm-project?rev=147761&view=rev
Log:
First brush with testing __gxx_personality_v0 reveals there is still a long way to go. But my understanding of what it is supposed to do continues to improve. I am currently contemplating whether I need to implement typeinfo before completing __gxx_personality_v0 in order to get matching catch handlers correct.
Modified:
libcxxabi/trunk/src/cxa_personality.cpp
Modified: libcxxabi/trunk/src/cxa_personality.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_personality.cpp?rev=147761&r1=147760&r2=147761&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_personality.cpp (original)
+++ libcxxabi/trunk/src/cxa_personality.cpp Sun Jan 8 17:50:46 2012
@@ -107,6 +107,10 @@
uintptr_t
readEncodedPointer(const uint8_t** data, uint8_t encoding)
{
+// TODO: Not quite rgiht. This should be able to read a 0 from the TType table
+// and not dereference it. Pasted in temporayr workaround
+// TODO: Sometimes this is clearly not always reading an encoded pointer, for
+// example a length in the call site table. Needs new name?
uintptr_t result = 0;
const uint8_t* p = *data;
if (encoding == DW_EH_PE_omit)
@@ -160,7 +164,8 @@
// do nothing
break;
case DW_EH_PE_pcrel:
- result += (uintptr_t)(*data);
+ if (result)
+ result += (uintptr_t)(*data);
break;
case DW_EH_PE_textrel:
case DW_EH_PE_datarel:
@@ -172,12 +177,37 @@
break;
}
// then apply indirection
- if (encoding & DW_EH_PE_indirect)
+ if (result && (encoding & DW_EH_PE_indirect))
result = *((uintptr_t*)result);
*data = p;
return result;
}
+static
+const uint8_t*
+getTTypeEntry(int64_t typeOffset, const uint8_t* classInfo, uint8_t ttypeEncoding)
+{
+ switch (ttypeEncoding & 0x0F)
+ {
+ case DW_EH_PE_absptr:
+ typeOffset *= sizeof(void*);
+ break;
+ case DW_EH_PE_udata2:
+ case DW_EH_PE_sdata2:
+ typeOffset *= 2;
+ break;
+ case DW_EH_PE_udata4:
+ case DW_EH_PE_sdata4:
+ typeOffset *= 4;
+ break;
+ case DW_EH_PE_udata8:
+ case DW_EH_PE_sdata8:
+ typeOffset *= 8;
+ break;
+ }
+ return classInfo - typeOffset;
+}
+
/// 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,
@@ -195,29 +225,43 @@
/// a cleanup was found
static
bool
-handleActionValue(const std::type_info** classInfo, uintptr_t actionEntry,
- _Unwind_Exception* exceptionObject)
+handleActionValue(const uint8_t* classInfo, uintptr_t actionEntry,
+ _Unwind_Exception* exceptionObject, uint8_t ttypeEncoding)
{
__cxa_exception* excp = (__cxa_exception*)(exceptionObject+1) - 1;
const std::type_info* excpType = excp->exceptionType;
const uint8_t* actionPos = (uint8_t*)actionEntry;
- for (int i = 0; true; ++i)
+ while (true)
{
// Each emitted dwarf action corresponds to a 2 tuple of
// type info address offset, and action offset to the next
// emitted action.
+ const uint8_t* SactionPos = actionPos;
int64_t typeOffset = readSLEB128(&actionPos);
const uint8_t* tempActionPos = actionPos;
int64_t actionOffset = readSLEB128(&tempActionPos);
- 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) && (excpType == classInfo[-typeOffset]))
+ if (typeOffset > 0) // a catch handler
+ {
+ const uint8_t* TTypeEntry = getTTypeEntry(typeOffset, classInfo,
+ ttypeEncoding);
+ const std::type_info* catchType =
+ (const std::type_info*)readEncodedPointer(&TTypeEntry,
+ ttypeEncoding);
+ // catchType == 0 -> catch (...)
+ if (catchType == 0 || excpType == catchType)
+ {
+ excp->handlerSwitchValue = typeOffset;
+ excp->actionRecord = SactionPos;
+ return true;
+ }
+ }
+ else if (typeOffset < 0) // an exception spec
{
- excp->handlerSwitchValue = i + 1;
- return true;
}
- if (!actionOffset)
+ else // typeOffset == 0 // a clean up
+ {
+ }
+ if (actionOffset == 0)
break;
actionPos += actionOffset;
}
@@ -231,7 +275,12 @@
bool
contains_handler(_Unwind_Exception* exceptionObject, _Unwind_Context* context)
{
+ __cxa_exception* excp = (__cxa_exception*)(exceptionObject+1) - 1;
const uint8_t* lsda = (const uint8_t*)_Unwind_GetLanguageSpecificData(context);
+ excp->languageSpecificData = lsda;
+ // set adjustedPtr! __cxa_get_exception_ptr and __cxa_begin_catch use it.
+ // TODO: Put it where it is supposed to be and adjust it properly
+ excp->adjustedPtr = exceptionObject+1;
if (lsda)
{
// Get the current instruction pointer and offset it before next
@@ -241,7 +290,7 @@
// emitted dwarf code)
uintptr_t funcStart = _Unwind_GetRegionStart(context);
uintptr_t pcOffset = pc - funcStart;
- const std::type_info** classInfo = NULL;
+ const uint8_t* classInfo = NULL;
// Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding
// dwarf emission
// Parse LSDA header.
@@ -249,13 +298,14 @@
if (lpStartEncoding != DW_EH_PE_omit)
(void)readEncodedPointer(&lsda, lpStartEncoding);
uint8_t ttypeEncoding = *lsda++;
+ // TODO: preflight ttypeEncoding here and return error if there's a problem
if (ttypeEncoding != DW_EH_PE_omit)
{
// Calculate type info locations in emitted dwarf code which
// were flagged by type info arguments to llvm.eh.selector
// intrinsic
uintptr_t classInfoOffset = readULEB128(&lsda);
- classInfo = (const std::type_info**)(lsda + classInfoOffset);
+ classInfo = lsda + classInfoOffset;
}
// Walk call-site table looking for range that
// includes current PC.
@@ -265,7 +315,6 @@
const uint8_t* callSiteTableEnd = callSiteTableStart + callSiteTableLength;
const uint8_t* actionTableStart = callSiteTableEnd;
const uint8_t* callSitePtr = callSiteTableStart;
- __cxa_exception* excp = (__cxa_exception*)(exceptionObject+1) - 1;
while (callSitePtr < callSiteTableEnd)
{
uintptr_t start = readEncodedPointer(&callSitePtr, callSiteEncoding);
@@ -277,21 +326,22 @@
continue; // no landing pad for this entry
if (actionEntry)
actionEntry += ((uintptr_t)actionTableStart) - 1;
- bool exceptionMatched = false;
if ((start <= pcOffset) && (pcOffset < (start + length)))
{
- excp->actionRecord = (const unsigned char*)(funcStart + landingPad);
+ excp->catchTemp = (void*)(funcStart + landingPad);
if (actionEntry)
return handleActionValue(classInfo,
actionEntry,
- exceptionObject);
+ exceptionObject,
+ ttypeEncoding);
// 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.
- break;
+ return true; //?
}
}
+ // Not found, need to properly terminate
}
return false;
}
@@ -304,7 +354,7 @@
__cxa_exception* excp = (__cxa_exception*)(exceptionObject+1) - 1;
_Unwind_SetGR(context, __builtin_eh_return_data_regno(0), (uintptr_t)exceptionObject);
_Unwind_SetGR(context, __builtin_eh_return_data_regno(1), excp->handlerSwitchValue);
- _Unwind_SetIP(context, (uintptr_t)excp->actionRecord);
+ _Unwind_SetIP(context, (uintptr_t)excp->catchTemp);
return _URC_INSTALL_CONTEXT;
}
@@ -315,7 +365,7 @@
__cxa_exception* excp = (__cxa_exception*)(exceptionObject+1) - 1;
_Unwind_SetGR(context, __builtin_eh_return_data_regno(0), (uintptr_t)exceptionObject);
_Unwind_SetGR(context, __builtin_eh_return_data_regno(1), 0);
- _Unwind_SetIP(context, (uintptr_t)excp->actionRecord);
+ _Unwind_SetIP(context, (uintptr_t)excp->catchTemp);
return _URC_INSTALL_CONTEXT;
}
@@ -334,7 +384,7 @@
{
if (version == 1 && exceptionObject != 0 && context != 0)
{
- bool native_exception = (exceptionClass & 0xFFF0) == 0x432B2B00;
+ bool native_exception = (exceptionClass & 0xFFFFFF00) == 0x432B2B00;
bool force_unwind = actions & _UA_FORCE_UNWIND;
if (native_exception && !force_unwind)
{
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