view ir/irfunction.cpp @ 1117:4c20fcc4252b

Fun with parameter attributes: For several of the "synthetic" parameters added to D functions, we can apply noalias and nocapture. They are sret parameters, 'nest' pointers passed to nested functions, and _argptr: Nocapture: - Sret and nest are nocapture because they don't represent D-level variables, and thus the callee can't (validly) obtain a pointer to them, let alone keep it around after it returns. - _argptr is nocapture because although the callee has access to it as a pointer, that pointer is invalidated when it returns. All three are noalias because they're function-local variables - Sret and _argptr are noalias because they're freshly alloca'd memory only used for a single function call that's not allowed to keep an aliasing pointer to it around (since the parameter is nocapture). - 'Nest' is noalias because the callee only ever has access to one such pointer per parent function, and every parent function has a different one. This commit also ensures attributes set on sret, _arguments and _argptr are propagated to calls to such functions. It also adds one exception to the general rule that attributes on function types should propagate to calls: the type of a delegate's function pointer has a 'nest' parameter, but this can either be a true 'nest' (for delegates to nested functions) or a 'this' (for delegates to member functions). Since 'this' is neither noalias nor nocapture, and there's generally no way to tell which one it is, we remove these attributes at the call site if the callee is a delegate.
author Frits van Bommel <fvbommel wxs.nl>
date Sat, 14 Mar 2009 22:15:31 +0100
parents dc608dc33081
children 8699c450a1a0
line wrap: on
line source


#include "gen/llvm.h"
#include "gen/tollvm.h"
#include "gen/abi.h"
#include "gen/dvalue.h"
#include "gen/logger.h"
#include "ir/irfunction.h"
#include "ir/irfuncty.h"

#include <sstream>

//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////

IrFuncTyArg::IrFuncTyArg(Type* t, bool bref, unsigned a)
{
    type = t;
    ltype = bref ? DtoType(t->pointerTo()) : DtoType(t);
    attrs = a;
    byref = bref;
    rewrite = NULL;
}

bool IrFuncTyArg::isInReg() const { return (attrs & llvm::Attribute::InReg) != 0; }
bool IrFuncTyArg::isSRet() const  { return (attrs & llvm::Attribute::StructRet) != 0; }
bool IrFuncTyArg::isByVal() const { return (attrs & llvm::Attribute::ByVal) != 0; }

//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////

llvm::Value* IrFuncTy::putRet(Type* dty, DValue* val)
{
    assert(!arg_sret);
    if (ret->rewrite) {
        Logger::println("Rewrite: putRet");
        LOG_SCOPE
        return ret->rewrite->put(dty, val);
    }
    return val->getRVal();
}

llvm::Value* IrFuncTy::getRet(Type* dty, DValue* val)
{
    assert(!arg_sret);
    if (ret->rewrite) {
        Logger::println("Rewrite: getRet");
        LOG_SCOPE
        return ret->rewrite->get(dty, val);
    }
    return val->getRVal();
}

llvm::Value* IrFuncTy::putParam(Type* dty, int idx, DValue* val)
{
    assert(idx >= 0 && idx < args.size() && "invalid putParam");
    if (args[idx]->rewrite) {
        Logger::println("Rewrite: putParam");
        LOG_SCOPE
        return args[idx]->rewrite->put(dty, val);
    }
    return val->getRVal();
}

llvm::Value* IrFuncTy::getParam(Type* dty, int idx, DValue* val)
{
    assert(idx >= 0 && idx < args.size() && "invalid getParam");
    if (args[idx]->rewrite) {
        Logger::println("Rewrite: getParam (get)");
        LOG_SCOPE
        return args[idx]->rewrite->get(dty, val);
    }
    return val->getRVal();
}

void IrFuncTy::getParam(Type* dty, int idx, DValue* val, llvm::Value* lval)
{
    assert(idx >= 0 && idx < args.size() && "invalid getParam");

    if (args[idx]->rewrite)
    {
        Logger::println("Rewrite: getParam (getL)");
        LOG_SCOPE
        args[idx]->rewrite->getL(dty, val, lval);
        return;
    }

    DtoStore(val->getRVal(), lval);
}

//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////

IrFunction::IrFunction(FuncDeclaration* fd)
{
    decl = fd;

    Type* t = fd->type->toBasetype();
    assert(t->ty == Tfunction);
    type = (TypeFunction*)t;
    func = NULL;
    allocapoint = NULL;

    queued = false;
    defined = false;

    retArg = NULL;
    thisArg = NULL;
    nestArg = NULL;

    nestedVar = NULL;
    
    _arguments = NULL;
    _argptr = NULL;
    
    nextUnique.push(0);
}

std::string IrFunction::getScopedLabelName(const char* ident)
{
    if(labelScopes.empty())
        return std::string(ident);

    std::string result = "__";
    for(unsigned int i = 0; i < labelScopes.size(); ++i)
        result += labelScopes[i] + "_";
    return result + ident;
}

void IrFunction::pushUniqueLabelScope(const char* name)
{
    std::ostringstream uniquename;
    uniquename << name << nextUnique.top()++;
    nextUnique.push(0);
    labelScopes.push_back(uniquename.str());
}

void IrFunction::popLabelScope()
{
    labelScopes.pop_back();
    nextUnique.pop();
}

void IrFunction::setNeverInline()
{
    assert(!func->hasFnAttr(llvm::Attribute::AlwaysInline) && "function can't be never- and always-inline at the same time");
    func->addFnAttr(llvm::Attribute::NoInline);
}

void IrFunction::setAlwaysInline()
{
    assert(!func->hasFnAttr(llvm::Attribute::NoInline) && "function can't be never- and always-inline at the same time");
    func->addFnAttr(llvm::Attribute::AlwaysInline);
}