rust/src/librustc/middle/trans/context.rs

// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.


use driver::session;
use driver::session::NoDebugInfo;
use lib::llvm::{ContextRef, ModuleRef, ValueRef};
use lib::llvm::{llvm, TargetData, TypeNames};
use lib::llvm::mk_target_data;
use metadata::common::LinkMeta;
use middle::astencode;
use middle::resolve;
use middle::trans::adt;
use middle::trans::base;
use middle::trans::builder::Builder;
use middle::trans::common::{C_i32, C_null};
use middle::trans::common::{mono_id,ExternMap,tydesc_info,BuilderRef_res,Stats};
use middle::trans::base::{decl_crate_map};
use middle::trans::debuginfo;
use middle::trans::type_::Type;
use middle::ty;
use util::sha2::Sha256;
use util::nodemap::{NodeMap, NodeSet, DefIdMap};

use std::cell::{Cell, RefCell};
use std::c_str::ToCStr;
use std::local_data;
use std::libc::c_uint;
use collections::{HashMap, HashSet};
use syntax::ast;
use syntax::parse::token::InternedString;

pub struct CrateContext {
    sess: session::Session,
    llmod: ModuleRef,
    llcx: ContextRef,
    metadata_llmod: ModuleRef,
    td: TargetData,
    tn: TypeNames,
    externs: RefCell<ExternMap>,
    intrinsics: HashMap<&'static str, ValueRef>,
    item_vals: RefCell<NodeMap<ValueRef>>,
    exp_map2: resolve::ExportMap2,
    reachable: @RefCell<NodeSet>,
    item_symbols: RefCell<NodeMap<~str>>,
    link_meta: LinkMeta,
    drop_glues: RefCell<HashMap<ty::t, ValueRef>>,
    tydescs: RefCell<HashMap<ty::t, @tydesc_info>>,
    // Set when running emit_tydescs to enforce that no more tydescs are
    // created.
    finished_tydescs: Cell<bool>,
    // Track mapping of external ids to local items imported for inlining
    external: RefCell<DefIdMap<Option<ast::NodeId>>>,
    // Backwards version of the `external` map (inlined items to where they
    // came from)
    external_srcs: RefCell<NodeMap<ast::DefId>>,
    // A set of static items which cannot be inlined into other crates. This
    // will pevent in IIItem() structures from being encoded into the metadata
    // that is generated
    non_inlineable_statics: RefCell<NodeSet>,
    // Cache instances of monomorphized functions
    monomorphized: RefCell<HashMap<mono_id, ValueRef>>,
    monomorphizing: RefCell<DefIdMap<uint>>,
    // Cache generated vtables
    vtables: RefCell<HashMap<(ty::t, mono_id), ValueRef>>,
    // Cache of constant strings,
    const_cstr_cache: RefCell<HashMap<InternedString, ValueRef>>,

    // Reverse-direction for const ptrs cast from globals.
    // Key is an int, cast from a ValueRef holding a *T,
    // Val is a ValueRef holding a *[T].
    //
    // Needed because LLVM loses pointer->pointee association
    // when we ptrcast, and we have to ptrcast during translation
    // of a [T] const because we form a slice, a [*T,int] pair, not
    // a pointer to an LLVM array type.
    const_globals: RefCell<HashMap<int, ValueRef>>,

    // Cache of emitted const values
    const_values: RefCell<NodeMap<ValueRef>>,

    // Cache of external const values
    extern_const_values: RefCell<DefIdMap<ValueRef>>,

    impl_method_cache: RefCell<HashMap<(ast::DefId, ast::Name), ast::DefId>>,

    // Cache of closure wrappers for bare fn's.
    closure_bare_wrapper_cache: RefCell<HashMap<ValueRef, ValueRef>>,

    module_data: RefCell<HashMap<~str, ValueRef>>,
    lltypes: RefCell<HashMap<ty::t, Type>>,
    llsizingtypes: RefCell<HashMap<ty::t, Type>>,
    adt_reprs: RefCell<HashMap<ty::t, @adt::Repr>>,
    symbol_hasher: RefCell<Sha256>,
    type_hashcodes: RefCell<HashMap<ty::t, ~str>>,
    all_llvm_symbols: RefCell<HashSet<~str>>,
    tcx: ty::ctxt,
    maps: astencode::Maps,
    stats: @Stats,
    tydesc_type: Type,
    int_type: Type,
    opaque_vec_type: Type,
    builder: BuilderRef_res,
    crate_map: ValueRef,
    crate_map_name: ~str,
    // Set when at least one function uses GC. Needed so that
    // decl_gc_metadata knows whether to link to the module metadata, which
    // is not emitted by LLVM's GC pass when no functions use GC.
    uses_gc: bool,
    dbg_cx: Option<debuginfo::CrateDebugContext>,
    do_not_commit_warning_issued: Cell<bool>,
}

impl CrateContext {
    pub fn new(sess: session::Session,
               name: &str,
               tcx: ty::ctxt,
               emap2: resolve::ExportMap2,
               maps: astencode::Maps,
               symbol_hasher: Sha256,
               link_meta: LinkMeta,
               reachable: @RefCell<NodeSet>)
               -> CrateContext {
        unsafe {
            let llcx = llvm::LLVMContextCreate();
            set_task_llcx(llcx);
            let llmod = name.with_c_str(|buf| {
                llvm::LLVMModuleCreateWithNameInContext(buf, llcx)
            });
            let metadata_llmod = format!("{}_metadata", name).with_c_str(|buf| {
                llvm::LLVMModuleCreateWithNameInContext(buf, llcx)
            });
            let data_layout: &str = sess.targ_cfg.target_strs.data_layout;
            let targ_triple: &str = sess.targ_cfg.target_strs.target_triple;
            data_layout.with_c_str(|buf| {
                llvm::LLVMSetDataLayout(llmod, buf);
                llvm::LLVMSetDataLayout(metadata_llmod, buf);
            });
            targ_triple.with_c_str(|buf| {
                llvm::LLVMRustSetNormalizedTarget(llmod, buf);
                llvm::LLVMRustSetNormalizedTarget(metadata_llmod, buf);
            });
            let targ_cfg = sess.targ_cfg;

            let td = mk_target_data(sess.targ_cfg.target_strs.data_layout);
            let tn = TypeNames::new();

            let mut intrinsics = base::declare_intrinsics(llmod);
            if sess.opts.debuginfo != NoDebugInfo {
                base::declare_dbg_intrinsics(llmod, &mut intrinsics);
            }
            let int_type = Type::int(targ_cfg.arch);
            let tydesc_type = Type::tydesc(targ_cfg.arch);
            let opaque_vec_type = Type::opaque_vec(targ_cfg.arch);

            let mut str_slice_ty = Type::named_struct("str_slice");
            str_slice_ty.set_struct_body([Type::i8p(), int_type], false);

            tn.associate_type("tydesc", &tydesc_type);
            tn.associate_type("str_slice", &str_slice_ty);

            let (crate_map_name, crate_map) = decl_crate_map(sess, link_meta.clone(), llmod);
            let dbg_cx = if sess.opts.debuginfo != NoDebugInfo {
                Some(debuginfo::CrateDebugContext::new(llmod))
            } else {
                None
            };

            if sess.count_llvm_insns() {
                base::init_insn_ctxt()
            }

            CrateContext {
                 sess: sess,
                 llmod: llmod,
                 llcx: llcx,
                 metadata_llmod: metadata_llmod,
                 td: td,
                 tn: tn,
                 externs: RefCell::new(HashMap::new()),
                 intrinsics: intrinsics,
                 item_vals: RefCell::new(NodeMap::new()),
                 exp_map2: emap2,
                 reachable: reachable,
                 item_symbols: RefCell::new(NodeMap::new()),
                 link_meta: link_meta,
                 drop_glues: RefCell::new(HashMap::new()),
                 tydescs: RefCell::new(HashMap::new()),
                 finished_tydescs: Cell::new(false),
                 external: RefCell::new(DefIdMap::new()),
                 external_srcs: RefCell::new(NodeMap::new()),
                 non_inlineable_statics: RefCell::new(NodeSet::new()),
                 monomorphized: RefCell::new(HashMap::new()),
                 monomorphizing: RefCell::new(DefIdMap::new()),
                 vtables: RefCell::new(HashMap::new()),
                 const_cstr_cache: RefCell::new(HashMap::new()),
                 const_globals: RefCell::new(HashMap::new()),
                 const_values: RefCell::new(NodeMap::new()),
                 extern_const_values: RefCell::new(DefIdMap::new()),
                 impl_method_cache: RefCell::new(HashMap::new()),
                 closure_bare_wrapper_cache: RefCell::new(HashMap::new()),
                 module_data: RefCell::new(HashMap::new()),
                 lltypes: RefCell::new(HashMap::new()),
                 llsizingtypes: RefCell::new(HashMap::new()),
                 adt_reprs: RefCell::new(HashMap::new()),
                 symbol_hasher: RefCell::new(symbol_hasher),
                 type_hashcodes: RefCell::new(HashMap::new()),
                 all_llvm_symbols: RefCell::new(HashSet::new()),
                 tcx: tcx,
                 maps: maps,
                 stats: @Stats {
                   n_static_tydescs: Cell::new(0u),
                   n_glues_created: Cell::new(0u),
                   n_null_glues: Cell::new(0u),
                   n_real_glues: Cell::new(0u),
                   n_fns: Cell::new(0u),
                   n_monos: Cell::new(0u),
                   n_inlines: Cell::new(0u),
                   n_closures: Cell::new(0u),
                   n_llvm_insns: Cell::new(0u),
                   llvm_insns: RefCell::new(HashMap::new()),
                   fn_stats: RefCell::new(~[]),
                 },
                 tydesc_type: tydesc_type,
                 int_type: int_type,
                 opaque_vec_type: opaque_vec_type,
                 builder: BuilderRef_res(llvm::LLVMCreateBuilderInContext(llcx)),
                 crate_map: crate_map,
                 crate_map_name: crate_map_name,
                 uses_gc: false,
                 dbg_cx: dbg_cx,
                 do_not_commit_warning_issued: Cell::new(false),
            }
        }
    }

    pub fn builder<'a>(&'a self) -> Builder<'a> {
        Builder::new(self)
    }

    pub fn const_inbounds_gepi(&self,
                               pointer: ValueRef,
                               indices: &[uint]) -> ValueRef {
        debug!("const_inbounds_gepi: pointer={} indices={:?}",
               self.tn.val_to_str(pointer), indices);
        let v: ~[ValueRef] =
            indices.iter().map(|i| C_i32(*i as i32)).collect();
        unsafe {
            llvm::LLVMConstInBoundsGEP(pointer,
                                       v.as_ptr(),
                                       indices.len() as c_uint)
        }
    }

    pub fn offsetof_gep(&self,
                        llptr_ty: Type,
                        indices: &[uint]) -> ValueRef {
        /*!
         * Returns the offset of applying the given GEP indices
         * to an instance of `llptr_ty`. Similar to `offsetof` in C,
         * except that `llptr_ty` must be a pointer type.
         */

        unsafe {
            let null = C_null(llptr_ty);
            llvm::LLVMConstPtrToInt(self.const_inbounds_gepi(null, indices),
                                    self.int_type.to_ref())
        }
    }
}

#[unsafe_destructor]
impl Drop for CrateContext {
    fn drop(&mut self) {
        unset_task_llcx();
    }
}

local_data_key!(task_local_llcx_key: @ContextRef)

pub fn task_llcx() -> ContextRef {
    let opt = local_data::get(task_local_llcx_key, |k| k.map(|k| *k));
    *opt.expect("task-local LLVMContextRef wasn't ever set!")
}

fn set_task_llcx(c: ContextRef) {
    local_data::set(task_local_llcx_key, @c);
}

fn unset_task_llcx() {
    local_data::pop(task_local_llcx_key);
}