ccall.cpp

// --- the ccall intrinsic ---

// --- library symbol lookup ---

// map from "libX" to full soname "libX.so.ver"
#if defined(__linux__)
static std::map<std::string, std::string> sonameMap;
static bool got_sonames = false;

static void read_sonames()
{
    char *line=NULL;
    size_t sz=0;
    FILE *ldc = popen("/sbin/ldconfig -p", "r");

    while (!feof(ldc)) {
        ssize_t n = getline(&line, &sz, ldc);
        if (n == -1)
            break;
        if (n > 2 && isspace(line[0])) {
            int i=0;
            while (isspace(line[++i])) ;
            char *name = &line[i];
            char *dot = strstr(name, ".so");
            char *nxt = strchr(name, ' ');
            if (dot != NULL && nxt != NULL) {
                std::string pfx(name, dot - name);
                std::string soname(name, nxt - name);
                sonameMap[pfx] = soname;
            }
        }
    }

    free(line);
    pclose(ldc);
}

extern "C" const char *jl_lookup_soname(char *pfx, size_t n)
{
    if (!got_sonames) {
        read_sonames();
        got_sonames = true;
    }
    std::string str(pfx, n);
    if (sonameMap.find(str) != sonameMap.end()) {
        return sonameMap[str].c_str();
    }
    return NULL;
}
#endif

// map from user-specified lib names to handles
static std::map<std::string, void*> libMap;

int add_library_mapping(char *lib, void *hnd)
{
    if(libMap[lib] == NULL && hnd != NULL) {
        libMap[lib] = hnd;
        return 0;
    } else
        return -1;
}

static void *add_library_sym(char *name, char *lib)
{
    void *hnd;
    if (lib == NULL) {
        hnd = jl_dl_handle;
    }
    else {
        hnd = libMap[lib];
        if (hnd == NULL) {
            hnd = jl_load_dynamic_library(lib, JL_RTLD_DEFAULT);
            if (hnd != NULL)
            libMap[lib] = hnd;
            else
                return NULL;
        }
    }
    // add a symbol->address mapping for the JIT
    void *sval = jl_dlsym_e((uv_lib_t*)hnd, name);
    if (lib != NULL && hnd != jl_dl_handle) {
        void *exist = sys::DynamicLibrary::SearchForAddressOfSymbol(name);
        if (exist != NULL && exist != sval &&
            // openlibm conflicts with libm, and lots of our libraries
            // (including LLVM) link to libm. fortunately AddSymbol() is
            // able to resolve these in favor of openlibm, but this could
            // be an issue in the future (TODO).
            strcmp(lib,"libopenlibm")) {
            ios_printf(ios_stderr, "Warning: Possible conflict in library symbol %s\n", name);
        }
        sys::DynamicLibrary::AddSymbol(name, sval);
    }
    return sval;
}

// --- argument passing and scratch space utilities ---

static Function *value_to_pointer_func;

// TODO: per-thread
static char *temp_arg_area;
static const uint32_t arg_area_sz = 4196;
static uint32_t arg_area_loc;
#define N_TEMP_ARG_BLOCKS 1024
static void *temp_arg_blocks[N_TEMP_ARG_BLOCKS];
static uint32_t arg_block_n = 0;
static Function *save_arg_area_loc_func;
static Function *restore_arg_area_loc_func;

static uint64_t save_arg_area_loc()
{
    return (((uint64_t)arg_block_n)<<32) | ((uint64_t)arg_area_loc);
}

static void restore_arg_area_loc(uint64_t l)
{
    arg_area_loc = l&0xffffffff;
    uint32_t ab = l>>32;
    while (arg_block_n > ab) {
        arg_block_n--;
        free(temp_arg_blocks[arg_block_n]);
    }
}

static void *alloc_temp_arg_space(uint32_t sz)
{
    void *p;
    if (arg_area_loc+sz > arg_area_sz) {
#ifdef JL_GC_MARKSWEEP
        if (arg_block_n >= N_TEMP_ARG_BLOCKS)
            jl_error("internal compiler error: out of temporary argument space in ccall");
        p = malloc(sz);
        temp_arg_blocks[arg_block_n++] = p;
#else
#error "fixme"
#endif
    }
    else {
        p = &temp_arg_area[arg_area_loc];
        arg_area_loc += sz;
    }
    return p;
}

static void *alloc_temp_arg_copy(void *obj, uint32_t sz)
{
    void *p = alloc_temp_arg_space(sz);
    memcpy(p, obj, sz);
    return p;
}

// this is a run-time function
// warning: cannot allocate memory except using alloc_temp_arg_space
extern "C" void *jl_value_to_pointer(jl_value_t *jt, jl_value_t *v, int argn,
                                     int addressof)
{
    jl_value_t *jvt = (jl_value_t*)jl_typeof(v);
    if (addressof) {
        if (jvt == jt) {
            if (jl_is_bitstype(jvt)) {
                size_t osz = jl_datatype_size(jt);
                return alloc_temp_arg_copy(jl_data_ptr(v), osz);
            }
            else if (!jl_is_tuple(jvt) && jl_is_leaf_type(jvt) && !jl_is_array_type(jvt)) {
                return v + 1;
            }
        }
        goto value_to_pointer_error;
    }
    else {
        if (jl_is_cpointer_type(jvt) && jl_tparam0(jvt) == jt) {
            return (void*)jl_unbox_voidpointer(v);
        }
    }

    if (((jl_value_t*)jl_uint8_type == jt ||
         (jl_value_t*)jl_int8_type == jt) && jl_is_byte_string(v)) {
        return jl_string_data(v);
    }
    if (jl_is_array_type(jvt)) {
        if (jl_tparam0(jl_typeof(v)) == jt || jt==(jl_value_t*)jl_bottom_type)
            return ((jl_array_t*)v)->data;
        if (jl_is_cpointer_type(jt)) {
            jl_array_t *ar = (jl_array_t*)v;
            void **temp=(void**)alloc_temp_arg_space(jl_array_len(ar)*sizeof(void*));
            size_t i;
            for(i=0; i < jl_array_len(ar); i++) {
                temp[i] = jl_value_to_pointer(jl_tparam0(jt),
                                              jl_arrayref(ar, i), argn, 0);
            }
            return temp;
        }
    }

 value_to_pointer_error:
    std::map<int, std::string>::iterator it = argNumberStrings.find(argn);
    if (it == argNumberStrings.end()) {
        std::stringstream msg;
        msg << "argument ";
        msg << argn;
        argNumberStrings[argn] = msg.str();
        it = argNumberStrings.find(argn);
    }
    jl_value_t *targ=NULL, *pty=NULL;
    JL_GC_PUSH(&targ, &pty);
    targ = (jl_value_t*)jl_tuple1(jt);
    pty = (jl_value_t*)jl_apply_type((jl_value_t*)jl_pointer_type,
                                     (jl_tuple_t*)targ);
    jl_type_error_rt("ccall", (*it).second.c_str(), pty, v);
    // doesn't return
    return (jl_value_t*)jl_null;
}

static Value *julia_to_native(Type *ty, jl_value_t *jt, Value *jv,
                              jl_value_t *argex, bool addressOf,
                              int argn, jl_codectx_t *ctx)
{
    Type *vt = jv->getType();
    if (ty == jl_pvalue_llvmt) {
        return boxed(jv);
    }
    else if (ty == vt && !addressOf) {
        return jv;
    }
    else if (vt != jl_pvalue_llvmt) {
        // argument value is unboxed
        if (addressOf) {
            if (ty->isPointerTy() && ty->getContainedType(0)==vt) {
                // pass the address of an alloca'd thing, not a box
                // since those are immutable.
                Value *slot = builder.CreateAlloca(vt);
                builder.CreateStore(jv, slot);
                return builder.CreateBitCast(slot, ty);
            }
        }
        else if ((vt->isIntegerTy() && ty->isIntegerTy()) ||
                 (vt->isFloatingPointTy() && ty->isFloatingPointTy()) ||
                 (vt->isPointerTy() && ty->isPointerTy())) {
            if (vt->getPrimitiveSizeInBits() ==
                ty->getPrimitiveSizeInBits()) {
                return builder.CreateBitCast(jv, ty);
            }
        }
        // error. box for error handling.
        jv = boxed(jv);
    }
    else if (jl_is_cpointer_type(jt)) {
        assert(ty->isPointerTy());
        jl_value_t *aty = expr_type(argex, ctx);
        if (jl_is_array_type(aty) &&
            (jl_tparam0(jt) == jl_tparam0(aty) ||
             jl_tparam0(jt) == (jl_value_t*)jl_bottom_type)) {
            // array to pointer
            return builder.CreateBitCast(emit_arrayptr(jv), ty);
        }
        if (aty == (jl_value_t*)jl_ascii_string_type || aty == (jl_value_t*)jl_utf8_string_type) {
            return builder.CreateBitCast(emit_arrayptr(emit_nthptr(jv,1)), ty);
        }
        if (jl_is_structtype(aty) && jl_is_leaf_type(aty) && !jl_is_array_type(aty)) {
            if (!addressOf) {
                emit_error("ccall: expected addressOf operator", ctx);
                return literal_pointer_val(jl_nothing);
            }
            return builder.CreateBitCast(emit_nthptr_addr(jv, (size_t)1), ty); // skip type tag field
        }
        Value *p = builder.CreateCall4(value_to_pointer_func,
                                       literal_pointer_val(jl_tparam0(jt)), jv,
                                       ConstantInt::get(T_int32, argn),
                                       ConstantInt::get(T_int32, (int)addressOf));
        return builder.CreateBitCast(p, ty);
    }
    else if (jl_is_structtype(jt)) {
        if (addressOf)
            jl_error("ccall: unexpected addressOf operator"); // the only "safe" thing to emit here is the expected struct
        assert (ty->isStructTy() && (Type*)((jl_datatype_t*)jt)->struct_decl == ty);
        jl_value_t *aty = expr_type(argex, ctx);
        if (aty != jt) {
            std::stringstream msg;
            msg << "ccall argument ";
            msg << argn;
            emit_typecheck(jv, jt, msg.str(), ctx);
        }
        //TODO: check instead that prefix matches
        //if (!jl_is_structtype(aty))
        //    emit_typecheck(emit_typeof(jv), (jl_value_t*)jl_struct_kind, "ccall: Struct argument called with something that isn't a struct", ctx);
        // //safe thing would be to also check that jl_typeof(aty)->size > sizeof(ty) here and/or at runtime
        Value *pjv = builder.CreateBitCast(emit_nthptr_addr(jv, (size_t)1), PointerType::get(ty,0));
        return builder.CreateLoad(pjv, false);
    }
    // TODO: error for & with non-pointer argument type
    assert(jl_is_bitstype(jt));
    std::stringstream msg;
    msg << "ccall argument ";
    msg << argn;
    emit_typecheck(jv, jt, msg.str(), ctx);
    Value *p = data_pointer(jv);
    return builder.CreateLoad(builder.CreateBitCast(p,
                                                    PointerType::get(ty,0)),
                              false);
}

static jl_value_t *jl_signed_type=NULL;

// --- code generator for ccall itself ---

// ccall(pointer, rettype, (argtypes...), args...)
static Value *emit_ccall(jl_value_t **args, size_t nargs, jl_codectx_t *ctx)
{
    JL_NARGSV(ccall, 3);
    jl_value_t *ptr=NULL, *rt=NULL, *at=NULL;
    Value *jl_ptr=NULL;
    JL_GC_PUSH(&ptr, &rt, &at);
    ptr = static_eval(args[1], ctx, true);
    if (ptr == NULL) {
        jl_value_t *ptr_ty = expr_type(args[1], ctx);
        Value *arg1 = emit_unboxed(args[1], ctx);
        if (!jl_is_cpointer_type(ptr_ty)) {
            emit_cpointercheck(arg1, 
                    "ccall: function argument not a pointer or valid, constant expression", ctx);
        }
        jl_ptr = emit_unbox(T_size, T_psize, arg1);
    }
    rt  = jl_interpret_toplevel_expr_in(ctx->module, args[2],
                                        &jl_tupleref(ctx->sp,0),
                                        jl_tuple_len(ctx->sp)/2);
    if (jl_is_tuple(rt)) {
        std::string msg = "in " + ctx->funcName +
            ": ccall: missing return type";
        jl_error(msg.c_str());
    }
    at  = jl_interpret_toplevel_expr_in(ctx->module, args[3],
                                        &jl_tupleref(ctx->sp,0),
                                        jl_tuple_len(ctx->sp)/2);
    void *fptr=NULL;
    char *f_name=NULL, *f_lib=NULL;
    if (ptr != NULL) {
        if (jl_is_tuple(ptr) && jl_tuple_len(ptr)==1) {
            ptr = jl_tupleref(ptr,0);
        }
        if (jl_is_symbol(ptr))
            f_name = ((jl_sym_t*)ptr)->name;
        else if (jl_is_byte_string(ptr))
            f_name = jl_string_data(ptr);
        if (f_name != NULL) {
            // just symbol, default to JuliaDLHandle
#ifdef __WIN32__
         //TODO: store the f_lib name instead of fptr
        fptr = jl_dlsym_win32(f_name);
#else
            // will look in process symbol table
#endif
        }
        else if (jl_is_cpointer_type(jl_typeof(ptr))) {
            fptr = *(void**)jl_data_ptr(ptr);
        }
        else if (jl_is_tuple(ptr) && jl_tuple_len(ptr)>1) {
            jl_value_t *t0 = jl_tupleref(ptr,0);
            jl_value_t *t1 = jl_tupleref(ptr,1);
            if (jl_is_symbol(t0))
                f_name = ((jl_sym_t*)t0)->name;
            else if (jl_is_byte_string(t0))
                f_name = jl_string_data(t0);
            else
                JL_TYPECHK(ccall, symbol, t0);
            if (jl_is_symbol(t1))
                f_lib = ((jl_sym_t*)t1)->name;
            else if (jl_is_byte_string(t1))
                f_lib = jl_string_data(t1);
            else
                JL_TYPECHK(ccall, symbol, t1);
        }
        else {
            JL_TYPECHK(ccall, pointer, ptr);
        }
    }
    if (f_name == NULL && fptr == NULL && jl_ptr == NULL) {
        JL_GC_POP();
        emit_error("ccall: null function pointer", ctx);
        return literal_pointer_val(jl_nothing);
    }

    JL_TYPECHK(ccall, type, rt);
    JL_TYPECHK(ccall, tuple, at);
    JL_TYPECHK(ccall, type, at);
    jl_tuple_t *tt = (jl_tuple_t*)at;
    std::vector<Type *> fargt(0);
    std::vector<Type *> fargt_sig(0);
    Type *lrt = julia_struct_to_llvm(rt);
    if (lrt == NULL) {
        JL_GC_POP();
        emit_error("ccall: return type doesn't correspond to a C type", ctx);
        return literal_pointer_val(jl_nothing);
    }
    size_t i;
    bool haspointers = false;
    bool isVa = false;
    size_t nargt = jl_tuple_len(tt);
    std::vector<AttributeWithIndex> attrs;

    for(i=0; i < nargt; i++) {
        jl_value_t *tti = jl_tupleref(tt,i);
        if (jl_is_vararg_type(tti)) {
            isVa = true;
            tti = jl_tparam0(tti);
        }
        if (jl_is_bitstype(tti)) {
            // see pull req #978. need to annotate signext/zeroext for
            // small integer arguments.
            jl_datatype_t *bt = (jl_datatype_t*)tti;
            if (bt->size < 4) {
                if (jl_signed_type == NULL) {
                    jl_signed_type = jl_get_global(jl_core_module,jl_symbol("Signed"));
                }
#ifdef LLVM32
                Attributes::AttrVal av;
                if (jl_signed_type && jl_subtype(tti, jl_signed_type, 0))
                    av = Attributes::SExt;
                else
                    av = Attributes::ZExt;
                attrs.push_back(AttributeWithIndex::get(getGlobalContext(), i+1,
                                                        ArrayRef<Attributes::AttrVal>(&av, 1)));
#else
                Attribute::AttrConst av;
                if (jl_signed_type && jl_subtype(tti, jl_signed_type, 0))
                    av = Attribute::SExt;
                else
                    av = Attribute::ZExt;
                attrs.push_back(AttributeWithIndex::get(i+1, av));
#endif
            }
        }
        Type *t = julia_struct_to_llvm(tti);
        if (t == NULL) {
            JL_GC_POP();
            std::stringstream msg;
            msg << "ccall: the type of argument ";
            msg << i+1;
            msg << " doesn't correspond to a C type";
            emit_error(msg.str(), ctx);
            return literal_pointer_val(jl_nothing);
        }
        fargt.push_back(t);
        if (!isVa)
            fargt_sig.push_back(t);
    }
    // check for calling convention specifier
    CallingConv::ID cc = CallingConv::C;
    jl_value_t *last = args[nargs];
    if (jl_is_expr(last)) {
        jl_sym_t *lhd = ((jl_expr_t*)last)->head;
        if (lhd == jl_symbol("stdcall")) {
            cc = CallingConv::X86_StdCall;
            nargs--;
        }
        else if (lhd == jl_symbol("cdecl")) {
            cc = CallingConv::C;
            nargs--;
        }
        else if (lhd == jl_symbol("fastcall")) {
            cc = CallingConv::X86_FastCall;
            nargs--;
        }
        else if (lhd == jl_symbol("thiscall")) {
            cc = CallingConv::X86_ThisCall;
            nargs--;
        }
    }
    
    if ((!isVa && jl_tuple_len(tt)  != (nargs-2)/2) ||
        ( isVa && jl_tuple_len(tt)-1 > (nargs-2)/2))
        jl_error("ccall: wrong number of arguments to C function");

    // some special functions
    if (fptr == &jl_array_ptr) {
        assert(lrt->isPointerTy());
        Value *ary = emit_expr(args[4], ctx);
        JL_GC_POP();
        return mark_julia_type(builder.CreateBitCast(emit_arrayptr(ary),lrt),
                               rt);
    }
    if (fptr == &jl_value_ptr) {
        assert(lrt->isPointerTy());
        Value *ary = emit_expr(args[4], ctx);
        JL_GC_POP();
        return mark_julia_type(builder.CreateBitCast(ary,lrt),rt);
    }

    // see if there are & arguments
    for(i=4; i < nargs+1; i+=2) {
        jl_value_t *argi = args[i];
        if (jl_is_expr(argi) && ((jl_expr_t*)argi)->head == amp_sym) {
            haspointers = true;
            break;
        }
    }

    // make LLVM function object for the target
    Value *llvmf;
    FunctionType *functype = FunctionType::get(lrt, fargt_sig, isVa);
    
    if (jl_ptr != NULL) {
        null_pointer_check(jl_ptr,ctx);
        Type *funcptype = PointerType::get(functype,0);
        llvmf = builder.CreateIntToPtr(jl_ptr, funcptype);
    } else if (fptr != NULL) {
        Type *funcptype = PointerType::get(functype,0);
        llvmf = literal_pointer_val(fptr, funcptype);
    }
    else {
        void *symaddr;
        if (f_lib != NULL)
            symaddr = add_library_sym(f_name, f_lib);
        else
            symaddr = sys::DynamicLibrary::SearchForAddressOfSymbol(f_name);
        if (symaddr == NULL) {
            JL_GC_POP();
            std::stringstream msg;
            msg << "ccall: could not find function ";
            msg << f_name;
            if (f_lib != NULL) {
                msg << " in library ";
                msg << f_lib;
            }
            emit_error(msg.str(), ctx);
            return literal_pointer_val(jl_nothing);
        }
        llvmf = jl_Module->getOrInsertFunction(f_name, functype);
    }

    // save temp argument area stack pointer
    Value *saveloc=NULL;
    Value *stacksave=NULL;
    if (haspointers) {
        // TODO: inline this
        saveloc = builder.CreateCall(save_arg_area_loc_func);
        stacksave =
            builder.CreateCall(Intrinsic::getDeclaration(jl_Module,
                                                         Intrinsic::stacksave));
    }

    // emit arguments
    Value *argvals[(nargs-3)/2];
    int last_depth = ctx->argDepth;
    int nargty = jl_tuple_len(tt);
    for(i=4; i < nargs+1; i+=2) {
        int ai = (i-4)/2;
        jl_value_t *argi = args[i];
        bool addressOf = false;
        if (jl_is_expr(argi) && ((jl_expr_t*)argi)->head == amp_sym) {
            addressOf = true;
            argi = jl_exprarg(argi,0);
        }
        Type *largty;
        jl_value_t *jargty;
        if (isVa && ai >= nargty-1) {
            largty = fargt[nargty-1];
            jargty = jl_tparam0(jl_tupleref(tt,nargty-1));
        }
        else {
            largty = fargt[ai];
            jargty = jl_tupleref(tt,ai);
        }
        Value *arg;
        if (largty == jl_pvalue_llvmt ||
                largty->isStructTy()) {
            arg = emit_expr(argi, ctx, true);
        }
        else {
            arg = emit_unboxed(argi, ctx);
            if (jl_is_bitstype(expr_type(argi, ctx))) {
                if (addressOf)
                    arg = emit_unbox(largty->getContainedType(0), largty, arg);
                else
                    arg = emit_unbox(largty, PointerType::get(largty,0), arg);
            }
        }
        /*
#ifdef JL_GC_MARKSWEEP
        // make sure args are rooted
        if (largty->isPointerTy() &&
            (largty == jl_pvalue_llvmt ||
             !jl_is_bits_type(expr_type(args[i], ctx)))) {
            make_gcroot(boxed(arg), ctx);
        }
#endif
        */
        argvals[ai] = julia_to_native(largty, jargty, arg, argi, addressOf,
                                      ai+1, ctx);
    }
    // the actual call
    Value *result = builder.CreateCall(llvmf,
                                       ArrayRef<Value*>(&argvals[0],(nargs-3)/2));
    if (cc != CallingConv::C)
        ((CallInst*)result)->setCallingConv(cc);

#ifdef LLVM32
    ((CallInst*)result)->setAttributes(AttrListPtr::get(getGlobalContext(), ArrayRef<AttributeWithIndex>(attrs)));
#else
    ((CallInst*)result)->setAttributes(AttrListPtr::get(attrs.data(),attrs.size()));
#endif
    // restore temp argument area stack pointer
    if (haspointers) {
        assert(saveloc != NULL);
        builder.CreateCall(restore_arg_area_loc_func, saveloc);
        assert(stacksave != NULL);
        builder.CreateCall(Intrinsic::getDeclaration(jl_Module,
                                                     Intrinsic::stackrestore),
                           stacksave);
    }
    ctx->argDepth = last_depth;
    if (0) { // Enable this to turn on SSPREQ (-fstack-protector) on the function containing this ccall
#ifdef LLVM32        
        ctx->f->addFnAttr(Attributes::StackProtectReq);
#else
        ctx->f->addFnAttr(Attribute::StackProtectReq);
#endif
    }

    JL_GC_POP();
    if (lrt == T_void)
        return literal_pointer_val((jl_value_t*)jl_nothing);
    if (lrt->isStructTy()) {
        //fprintf(stderr, "ccall rt: %s -> %s\n", f_name, ((jl_tag_type_t*)rt)->name->name->name);
        assert(jl_is_structtype(rt));
        Value *strct =
            builder.CreateCall(jlallocobj_func,
                               ConstantInt::get(T_size,
                                    sizeof(void*)+((jl_datatype_t*)rt)->size));
        builder.CreateStore(literal_pointer_val((jl_value_t*)rt),
                            emit_nthptr_addr(strct, (size_t)0));
        builder.CreateStore(result,
                            builder.CreateBitCast(
                                emit_nthptr_addr(strct, (size_t)1),
                                PointerType::get(lrt,0)));
        return mark_julia_type(strct, rt);
    }
    return mark_julia_type(result, rt);
}