view ir/irlandingpad.cpp @ 1650:40bd4a0d4870

Update to work with LLVM 2.7. Removed use of dyn_cast, llvm no compiles without exceptions and rtti by default. We do need exceptions for the libconfig stuff, but rtti isn't necessary (anymore). Debug info needs to be rewritten, as in LLVM 2.7 the format has completely changed. To have something to look at while rewriting, the old code has been wrapped inside #ifndef DISABLE_DEBUG_INFO , this means that you have to define this to compile at the moment. Updated tango 0.99.9 patch to include updated EH runtime code, which is needed for LLVM 2.7 as well.
author Tomas Lindquist Olsen
date Wed, 19 May 2010 12:42:32 +0200
parents f4c56ed32238
children
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#include "gen/llvm.h"
#include "gen/tollvm.h"
#include "gen/irstate.h"
#include "gen/runtime.h"
#include "gen/logger.h"
#include "gen/classes.h"
#include "gen/llvmhelpers.h"
#include "ir/irlandingpad.h"

IRLandingPadInfo::IRLandingPadInfo(Catch* catchstmt, llvm::BasicBlock* end)
: finallyBody(NULL)
{
    target = llvm::BasicBlock::Create(gIR->context(), "catch", gIR->topfunc(), end);
    gIR->scope() = IRScope(target,end);

    // assign storage to catch var
    if(catchstmt->var) {
        // use the same storage for all exceptions that are not accessed in
        // nested functions
    #if DMDV2
        if(!catchstmt->var->nestedrefs.dim) {
    #else
        if(!catchstmt->var->nestedref) {
    #endif
            assert(!catchstmt->var->ir.irLocal);
            catchstmt->var->ir.irLocal = new IrLocal(catchstmt->var);
            LLValue* catch_var = gIR->func()->gen->landingPadInfo.getExceptionStorage();
            catchstmt->var->ir.irLocal->value = gIR->ir->CreateBitCast(catch_var, getPtrToType(DtoType(catchstmt->var->type)));
        }

        // this will alloca if we haven't already and take care of nested refs
        DtoDeclarationExp(catchstmt->var);

        // the exception will only be stored in catch_var. copy it over if necessary
        if(catchstmt->var->ir.irLocal->value != gIR->func()->gen->landingPadInfo.getExceptionStorage()) {
            LLValue* exc = gIR->ir->CreateBitCast(DtoLoad(gIR->func()->gen->landingPadInfo.getExceptionStorage()), DtoType(catchstmt->var->type));
            DtoStore(exc, catchstmt->var->ir.irLocal->value);
        }
    }

    // emit handler, if there is one
    // handler is zero for instance for 'catch { debug foo(); }'
    if(catchstmt->handler)
        catchstmt->handler->toIR(gIR);

    if (!gIR->scopereturned())
        gIR->ir->CreateBr(end);

    assert(catchstmt->type);
    catchType = catchstmt->type->toBasetype()->isClassHandle();
    assert(catchType);
    catchType->codegen(Type::sir);
}

IRLandingPadInfo::IRLandingPadInfo(Statement* finallystmt)
: target(NULL), finallyBody(finallystmt), catchType(NULL)
{

}


void IRLandingPad::addCatch(Catch* catchstmt, llvm::BasicBlock* end)
{
    unpushed_infos.push_front(IRLandingPadInfo(catchstmt, end));
}

void IRLandingPad::addFinally(Statement* finallystmt)
{
    unpushed_infos.push_front(IRLandingPadInfo(finallystmt));
}

void IRLandingPad::push(llvm::BasicBlock* inBB)
{
    // store infos such that matches are right to left
    nInfos.push(infos.size());
    infos.insert(infos.end(), unpushed_infos.begin(), unpushed_infos.end());
    unpushed_infos.clear();

    constructLandingPad(inBB);

    // store as invoke target
    padBBs.push(inBB);
}

void IRLandingPad::pop()
{
    padBBs.pop();

    size_t n = nInfos.top();
    infos.resize(n);
    nInfos.pop();
}

llvm::BasicBlock* IRLandingPad::get()
{
    if(padBBs.size() == 0)
        return NULL;
    else
        return padBBs.top();
}

void IRLandingPad::constructLandingPad(llvm::BasicBlock* inBB)
{
    // save and rewrite scope
    IRScope savedscope = gIR->scope();
    gIR->scope() = IRScope(inBB,savedscope.end);

    // eh_ptr = llvm.eh.exception();
    llvm::Function* eh_exception_fn = GET_INTRINSIC_DECL(eh_exception);
    LLValue* eh_ptr = gIR->ir->CreateCall(eh_exception_fn);

    // build selector arguments
    LLSmallVector<LLValue*, 6> selectorargs;

    // put in classinfos in the right order
    bool hasFinally = false;
    std::deque<IRLandingPadInfo>::iterator it = infos.begin(), end = infos.end();
    for(; it != end; ++it)
    {
        if(it->finallyBody)
            hasFinally = true;
        else
        {
            if(catchToInt.find(it->catchType) == catchToInt.end())
            {
                int newval = 1 + catchToInt.size();
                catchToInt[it->catchType] = newval;
            }
            assert(it->catchType);
            assert(it->catchType->ir.irStruct);
            selectorargs.insert(selectorargs.begin(), it->catchType->ir.irStruct->getClassInfoSymbol());
        }
    }
    // if there's a finally, the eh table has to have a 0 action
    if(hasFinally)
        selectorargs.push_back(DtoConstUint(0));

    // personality fn
    llvm::Function* personality_fn = LLVM_D_GetRuntimeFunction(gIR->module, "_d_eh_personality");
    LLValue* personality_fn_arg = gIR->ir->CreateBitCast(personality_fn, getPtrToType(LLType::getInt8Ty(gIR->context())));
    selectorargs.insert(selectorargs.begin(), personality_fn_arg);

    // eh storage target
    selectorargs.insert(selectorargs.begin(), eh_ptr);

    // if there is a catch and some catch allocated storage, store exception object
    if(catchToInt.size() && catch_var)
    {
        const LLType* objectTy = DtoType(ClassDeclaration::object->type);
        gIR->ir->CreateStore(gIR->ir->CreateBitCast(eh_ptr, objectTy), catch_var);
    }

    // eh_sel = llvm.eh.selector(eh_ptr, cast(byte*)&_d_eh_personality, <selectorargs>);
    llvm::Function* eh_selector_fn = GET_INTRINSIC_DECL(eh_selector);
    LLValue* eh_sel = gIR->ir->CreateCall(eh_selector_fn, selectorargs.begin(), selectorargs.end());

    // emit finallys and switches that branch to catches until there are no more catches
    // then simply branch to the finally chain
    llvm::SwitchInst* switchinst = NULL;
    std::deque<IRLandingPadInfo>::reverse_iterator rit, rend = infos.rend();
    for(rit = infos.rbegin(); rit != rend; ++rit)
    {
        // if it's a finally, emit its code
        if(rit->finallyBody)
        {
            if(switchinst)
                switchinst = NULL;

            // since this may be emitted multiple times
            // give the labels a new scope
            gIR->func()->gen->pushUniqueLabelScope("finally");
            rit->finallyBody->toIR(gIR);
            gIR->func()->gen->popLabelScope();
        }
        // otherwise it's a catch and we'll add a switch case
        else
        {
            if(!switchinst)
            {
                switchinst = gIR->ir->CreateSwitch(eh_sel, llvm::BasicBlock::Create(gIR->context(), "switchdefault", gIR->topfunc(), gIR->scopeend()), infos.size());
                gIR->scope() = IRScope(switchinst->getDefaultDest(), gIR->scopeend());
            }
            // dubious comment
            // catches matched first get the largest switchval, so do size - unique int
            llvm::ConstantInt* switchval = DtoConstUint(catchToInt[rit->catchType]);
            // and make sure we don't add the same switchval twice, may happen with nested trys
            if(!switchinst->findCaseValue(switchval))
                switchinst->addCase(switchval, rit->target);
        }
    }

    // no catch matched and all finallys executed - resume unwind
    llvm::Function* unwind_resume_fn = LLVM_D_GetRuntimeFunction(gIR->module, "_d_eh_resume_unwind");
    gIR->ir->CreateCall(unwind_resume_fn, eh_ptr);
    gIR->ir->CreateUnreachable();

    gIR->scope() = savedscope;
}

LLValue* IRLandingPad::getExceptionStorage()
{
    if(!catch_var)
    {
        Logger::println("Making new catch var");
        catch_var = DtoAlloca(ClassDeclaration::object->type, "catchvar");
    }
    return catch_var;
}