| // Copyright 2012-2014 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 libc::c_uint; |
| use llvm::{self, ValueRef, BasicBlockRef}; |
| use llvm::debuginfo::DIScope; |
| use rustc::ty::{self, TypeFoldable}; |
| use rustc::ty::layout::{LayoutOf, TyLayout}; |
| use rustc::mir::{self, Mir}; |
| use rustc::ty::subst::Substs; |
| use rustc::infer::TransNormalize; |
| use rustc::session::config::FullDebugInfo; |
| use base; |
| use builder::Builder; |
| use common::{CodegenCx, Funclet}; |
| use debuginfo::{self, declare_local, VariableAccess, VariableKind, FunctionDebugContext}; |
| use monomorphize::Instance; |
| use abi::{ArgAttribute, FnType, PassMode}; |
| |
| use syntax_pos::{DUMMY_SP, NO_EXPANSION, BytePos, Span}; |
| use syntax::symbol::keywords; |
| |
| use std::iter; |
| |
| use rustc_data_structures::bitvec::BitVector; |
| use rustc_data_structures::indexed_vec::{IndexVec, Idx}; |
| |
| pub use self::constant::trans_static_initializer; |
| |
| use self::analyze::CleanupKind; |
| use self::place::PlaceRef; |
| use rustc::mir::traversal; |
| |
| use self::operand::{OperandRef, OperandValue}; |
| |
| /// Master context for translating MIR. |
| pub struct FunctionCx<'a, 'tcx:'a> { |
| mir: &'a mir::Mir<'tcx>, |
| |
| debug_context: debuginfo::FunctionDebugContext, |
| |
| llfn: ValueRef, |
| |
| cx: &'a CodegenCx<'a, 'tcx>, |
| |
| fn_ty: FnType<'tcx>, |
| |
| /// When unwinding is initiated, we have to store this personality |
| /// value somewhere so that we can load it and re-use it in the |
| /// resume instruction. The personality is (afaik) some kind of |
| /// value used for C++ unwinding, which must filter by type: we |
| /// don't really care about it very much. Anyway, this value |
| /// contains an alloca into which the personality is stored and |
| /// then later loaded when generating the DIVERGE_BLOCK. |
| personality_slot: Option<PlaceRef<'tcx>>, |
| |
| /// A `Block` for each MIR `BasicBlock` |
| blocks: IndexVec<mir::BasicBlock, BasicBlockRef>, |
| |
| /// The funclet status of each basic block |
| cleanup_kinds: IndexVec<mir::BasicBlock, analyze::CleanupKind>, |
| |
| /// When targeting MSVC, this stores the cleanup info for each funclet |
| /// BB. This is initialized as we compute the funclets' head block in RPO. |
| funclets: &'a IndexVec<mir::BasicBlock, Option<Funclet>>, |
| |
| /// This stores the landing-pad block for a given BB, computed lazily on GNU |
| /// and eagerly on MSVC. |
| landing_pads: IndexVec<mir::BasicBlock, Option<BasicBlockRef>>, |
| |
| /// Cached unreachable block |
| unreachable_block: Option<BasicBlockRef>, |
| |
| /// The location where each MIR arg/var/tmp/ret is stored. This is |
| /// usually an `PlaceRef` representing an alloca, but not always: |
| /// sometimes we can skip the alloca and just store the value |
| /// directly using an `OperandRef`, which makes for tighter LLVM |
| /// IR. The conditions for using an `OperandRef` are as follows: |
| /// |
| /// - the type of the local must be judged "immediate" by `is_llvm_immediate` |
| /// - the operand must never be referenced indirectly |
| /// - we should not take its address using the `&` operator |
| /// - nor should it appear in a place path like `tmp.a` |
| /// - the operand must be defined by an rvalue that can generate immediate |
| /// values |
| /// |
| /// Avoiding allocs can also be important for certain intrinsics, |
| /// notably `expect`. |
| locals: IndexVec<mir::Local, LocalRef<'tcx>>, |
| |
| /// Debug information for MIR scopes. |
| scopes: IndexVec<mir::VisibilityScope, debuginfo::MirDebugScope>, |
| |
| /// If this function is being monomorphized, this contains the type substitutions used. |
| param_substs: &'tcx Substs<'tcx>, |
| } |
| |
| impl<'a, 'tcx> FunctionCx<'a, 'tcx> { |
| pub fn monomorphize<T>(&self, value: &T) -> T |
| where T: TransNormalize<'tcx> |
| { |
| self.cx.tcx.trans_apply_param_substs(self.param_substs, value) |
| } |
| |
| pub fn set_debug_loc(&mut self, bx: &Builder, source_info: mir::SourceInfo) { |
| let (scope, span) = self.debug_loc(source_info); |
| debuginfo::set_source_location(&self.debug_context, bx, scope, span); |
| } |
| |
| pub fn debug_loc(&mut self, source_info: mir::SourceInfo) -> (DIScope, Span) { |
| // Bail out if debug info emission is not enabled. |
| match self.debug_context { |
| FunctionDebugContext::DebugInfoDisabled | |
| FunctionDebugContext::FunctionWithoutDebugInfo => { |
| return (self.scopes[source_info.scope].scope_metadata, source_info.span); |
| } |
| FunctionDebugContext::RegularContext(_) =>{} |
| } |
| |
| // In order to have a good line stepping behavior in debugger, we overwrite debug |
| // locations of macro expansions with that of the outermost expansion site |
| // (unless the crate is being compiled with `-Z debug-macros`). |
| if source_info.span.ctxt() == NO_EXPANSION || |
| self.cx.sess().opts.debugging_opts.debug_macros { |
| let scope = self.scope_metadata_for_loc(source_info.scope, source_info.span.lo()); |
| (scope, source_info.span) |
| } else { |
| // Walk up the macro expansion chain until we reach a non-expanded span. |
| // We also stop at the function body level because no line stepping can occur |
| // at the level above that. |
| let mut span = source_info.span; |
| while span.ctxt() != NO_EXPANSION && span.ctxt() != self.mir.span.ctxt() { |
| if let Some(info) = span.ctxt().outer().expn_info() { |
| span = info.call_site; |
| } else { |
| break; |
| } |
| } |
| let scope = self.scope_metadata_for_loc(source_info.scope, span.lo()); |
| // Use span of the outermost expansion site, while keeping the original lexical scope. |
| (scope, span) |
| } |
| } |
| |
| // DILocations inherit source file name from the parent DIScope. Due to macro expansions |
| // it may so happen that the current span belongs to a different file than the DIScope |
| // corresponding to span's containing visibility scope. If so, we need to create a DIScope |
| // "extension" into that file. |
| fn scope_metadata_for_loc(&self, scope_id: mir::VisibilityScope, pos: BytePos) |
| -> llvm::debuginfo::DIScope { |
| let scope_metadata = self.scopes[scope_id].scope_metadata; |
| if pos < self.scopes[scope_id].file_start_pos || |
| pos >= self.scopes[scope_id].file_end_pos { |
| let cm = self.cx.sess().codemap(); |
| let defining_crate = self.debug_context.get_ref(DUMMY_SP).defining_crate; |
| debuginfo::extend_scope_to_file(self.cx, |
| scope_metadata, |
| &cm.lookup_char_pos(pos).file, |
| defining_crate) |
| } else { |
| scope_metadata |
| } |
| } |
| } |
| |
| enum LocalRef<'tcx> { |
| Place(PlaceRef<'tcx>), |
| Operand(Option<OperandRef<'tcx>>), |
| } |
| |
| impl<'a, 'tcx> LocalRef<'tcx> { |
| fn new_operand(cx: &CodegenCx<'a, 'tcx>, layout: TyLayout<'tcx>) -> LocalRef<'tcx> { |
| if layout.is_zst() { |
| // Zero-size temporaries aren't always initialized, which |
| // doesn't matter because they don't contain data, but |
| // we need something in the operand. |
| LocalRef::Operand(Some(OperandRef::new_zst(cx, layout))) |
| } else { |
| LocalRef::Operand(None) |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| pub fn trans_mir<'a, 'tcx: 'a>( |
| cx: &'a CodegenCx<'a, 'tcx>, |
| llfn: ValueRef, |
| mir: &'a Mir<'tcx>, |
| instance: Instance<'tcx>, |
| sig: ty::FnSig<'tcx>, |
| ) { |
| let fn_ty = FnType::new(cx, sig, &[]); |
| debug!("fn_ty: {:?}", fn_ty); |
| let debug_context = |
| debuginfo::create_function_debug_context(cx, instance, sig, llfn, mir); |
| let bx = Builder::new_block(cx, llfn, "start"); |
| |
| if mir.basic_blocks().iter().any(|bb| bb.is_cleanup) { |
| bx.set_personality_fn(cx.eh_personality()); |
| } |
| |
| let cleanup_kinds = analyze::cleanup_kinds(&mir); |
| // Allocate a `Block` for every basic block, except |
| // the start block, if nothing loops back to it. |
| let reentrant_start_block = !mir.predecessors_for(mir::START_BLOCK).is_empty(); |
| let block_bxs: IndexVec<mir::BasicBlock, BasicBlockRef> = |
| mir.basic_blocks().indices().map(|bb| { |
| if bb == mir::START_BLOCK && !reentrant_start_block { |
| bx.llbb() |
| } else { |
| bx.build_sibling_block(&format!("{:?}", bb)).llbb() |
| } |
| }).collect(); |
| |
| // Compute debuginfo scopes from MIR scopes. |
| let scopes = debuginfo::create_mir_scopes(cx, mir, &debug_context); |
| let (landing_pads, funclets) = create_funclets(&bx, &cleanup_kinds, &block_bxs); |
| |
| let mut fx = FunctionCx { |
| mir, |
| llfn, |
| fn_ty, |
| cx, |
| personality_slot: None, |
| blocks: block_bxs, |
| unreachable_block: None, |
| cleanup_kinds, |
| landing_pads, |
| funclets: &funclets, |
| scopes, |
| locals: IndexVec::new(), |
| debug_context, |
| param_substs: { |
| assert!(!instance.substs.needs_infer()); |
| instance.substs |
| }, |
| }; |
| |
| let memory_locals = analyze::memory_locals(&fx); |
| |
| // Allocate variable and temp allocas |
| fx.locals = { |
| let args = arg_local_refs(&bx, &fx, &fx.scopes, &memory_locals); |
| |
| let mut allocate_local = |local| { |
| let decl = &mir.local_decls[local]; |
| let layout = bx.cx.layout_of(fx.monomorphize(&decl.ty)); |
| assert!(!layout.ty.has_erasable_regions()); |
| |
| if let Some(name) = decl.name { |
| // User variable |
| let debug_scope = fx.scopes[decl.source_info.scope]; |
| let dbg = debug_scope.is_valid() && bx.sess().opts.debuginfo == FullDebugInfo; |
| |
| if !memory_locals.contains(local.index()) && !dbg { |
| debug!("alloc: {:?} ({}) -> operand", local, name); |
| return LocalRef::new_operand(bx.cx, layout); |
| } |
| |
| debug!("alloc: {:?} ({}) -> place", local, name); |
| let place = PlaceRef::alloca(&bx, layout, &name.as_str()); |
| if dbg { |
| let (scope, span) = fx.debug_loc(decl.source_info); |
| declare_local(&bx, &fx.debug_context, name, layout.ty, scope, |
| VariableAccess::DirectVariable { alloca: place.llval }, |
| VariableKind::LocalVariable, span); |
| } |
| LocalRef::Place(place) |
| } else { |
| // Temporary or return place |
| if local == mir::RETURN_PLACE && fx.fn_ty.ret.is_indirect() { |
| debug!("alloc: {:?} (return place) -> place", local); |
| let llretptr = llvm::get_param(llfn, 0); |
| LocalRef::Place(PlaceRef::new_sized(llretptr, layout, layout.align)) |
| } else if memory_locals.contains(local.index()) { |
| debug!("alloc: {:?} -> place", local); |
| LocalRef::Place(PlaceRef::alloca(&bx, layout, &format!("{:?}", local))) |
| } else { |
| // If this is an immediate local, we do not create an |
| // alloca in advance. Instead we wait until we see the |
| // definition and update the operand there. |
| debug!("alloc: {:?} -> operand", local); |
| LocalRef::new_operand(bx.cx, layout) |
| } |
| } |
| }; |
| |
| let retptr = allocate_local(mir::RETURN_PLACE); |
| iter::once(retptr) |
| .chain(args.into_iter()) |
| .chain(mir.vars_and_temps_iter().map(allocate_local)) |
| .collect() |
| }; |
| |
| // Branch to the START block, if it's not the entry block. |
| if reentrant_start_block { |
| bx.br(fx.blocks[mir::START_BLOCK]); |
| } |
| |
| // Up until here, IR instructions for this function have explicitly not been annotated with |
| // source code location, so we don't step into call setup code. From here on, source location |
| // emitting should be enabled. |
| debuginfo::start_emitting_source_locations(&fx.debug_context); |
| |
| let rpo = traversal::reverse_postorder(&mir); |
| let mut visited = BitVector::new(mir.basic_blocks().len()); |
| |
| // Translate the body of each block using reverse postorder |
| for (bb, _) in rpo { |
| visited.insert(bb.index()); |
| fx.trans_block(bb); |
| } |
| |
| // Remove blocks that haven't been visited, or have no |
| // predecessors. |
| for bb in mir.basic_blocks().indices() { |
| // Unreachable block |
| if !visited.contains(bb.index()) { |
| debug!("trans_mir: block {:?} was not visited", bb); |
| unsafe { |
| llvm::LLVMDeleteBasicBlock(fx.blocks[bb]); |
| } |
| } |
| } |
| } |
| |
| fn create_funclets<'a, 'tcx>( |
| bx: &Builder<'a, 'tcx>, |
| cleanup_kinds: &IndexVec<mir::BasicBlock, CleanupKind>, |
| block_bxs: &IndexVec<mir::BasicBlock, BasicBlockRef>) |
| -> (IndexVec<mir::BasicBlock, Option<BasicBlockRef>>, |
| IndexVec<mir::BasicBlock, Option<Funclet>>) |
| { |
| block_bxs.iter_enumerated().zip(cleanup_kinds).map(|((bb, &llbb), cleanup_kind)| { |
| match *cleanup_kind { |
| CleanupKind::Funclet if base::wants_msvc_seh(bx.sess()) => { |
| let cleanup_bx = bx.build_sibling_block(&format!("funclet_{:?}", bb)); |
| let cleanup = cleanup_bx.cleanup_pad(None, &[]); |
| cleanup_bx.br(llbb); |
| (Some(cleanup_bx.llbb()), Some(Funclet::new(cleanup))) |
| } |
| _ => (None, None) |
| } |
| }).unzip() |
| } |
| |
| /// Produce, for each argument, a `ValueRef` pointing at the |
| /// argument's value. As arguments are places, these are always |
| /// indirect. |
| fn arg_local_refs<'a, 'tcx>(bx: &Builder<'a, 'tcx>, |
| fx: &FunctionCx<'a, 'tcx>, |
| scopes: &IndexVec<mir::VisibilityScope, debuginfo::MirDebugScope>, |
| memory_locals: &BitVector) |
| -> Vec<LocalRef<'tcx>> { |
| let mir = fx.mir; |
| let tcx = bx.tcx(); |
| let mut idx = 0; |
| let mut llarg_idx = fx.fn_ty.ret.is_indirect() as usize; |
| |
| // Get the argument scope, if it exists and if we need it. |
| let arg_scope = scopes[mir::ARGUMENT_VISIBILITY_SCOPE]; |
| let arg_scope = if arg_scope.is_valid() && bx.sess().opts.debuginfo == FullDebugInfo { |
| Some(arg_scope.scope_metadata) |
| } else { |
| None |
| }; |
| |
| let deref_op = unsafe { |
| [llvm::LLVMRustDIBuilderCreateOpDeref()] |
| }; |
| |
| mir.args_iter().enumerate().map(|(arg_index, local)| { |
| let arg_decl = &mir.local_decls[local]; |
| |
| let name = if let Some(name) = arg_decl.name { |
| name.as_str().to_string() |
| } else { |
| format!("arg{}", arg_index) |
| }; |
| |
| if Some(local) == mir.spread_arg { |
| // This argument (e.g. the last argument in the "rust-call" ABI) |
| // is a tuple that was spread at the ABI level and now we have |
| // to reconstruct it into a tuple local variable, from multiple |
| // individual LLVM function arguments. |
| |
| let arg_ty = fx.monomorphize(&arg_decl.ty); |
| let tupled_arg_tys = match arg_ty.sty { |
| ty::TyTuple(ref tys, _) => tys, |
| _ => bug!("spread argument isn't a tuple?!") |
| }; |
| |
| let place = PlaceRef::alloca(bx, bx.cx.layout_of(arg_ty), &name); |
| for i in 0..tupled_arg_tys.len() { |
| let arg = &fx.fn_ty.args[idx]; |
| idx += 1; |
| arg.store_fn_arg(bx, &mut llarg_idx, place.project_field(bx, i)); |
| } |
| |
| // Now that we have one alloca that contains the aggregate value, |
| // we can create one debuginfo entry for the argument. |
| arg_scope.map(|scope| { |
| let variable_access = VariableAccess::DirectVariable { |
| alloca: place.llval |
| }; |
| declare_local( |
| bx, |
| &fx.debug_context, |
| arg_decl.name.unwrap_or(keywords::Invalid.name()), |
| arg_ty, scope, |
| variable_access, |
| VariableKind::ArgumentVariable(arg_index + 1), |
| DUMMY_SP |
| ); |
| }); |
| |
| return LocalRef::Place(place); |
| } |
| |
| let arg = &fx.fn_ty.args[idx]; |
| idx += 1; |
| if arg.pad.is_some() { |
| llarg_idx += 1; |
| } |
| |
| if arg_scope.is_none() && !memory_locals.contains(local.index()) { |
| // We don't have to cast or keep the argument in the alloca. |
| // FIXME(eddyb): We should figure out how to use llvm.dbg.value instead |
| // of putting everything in allocas just so we can use llvm.dbg.declare. |
| let local = |op| LocalRef::Operand(Some(op)); |
| match arg.mode { |
| PassMode::Ignore => { |
| return local(OperandRef::new_zst(bx.cx, arg.layout)); |
| } |
| PassMode::Direct(_) => { |
| let llarg = llvm::get_param(bx.llfn(), llarg_idx as c_uint); |
| bx.set_value_name(llarg, &name); |
| llarg_idx += 1; |
| return local( |
| OperandRef::from_immediate_or_packed_pair(bx, llarg, arg.layout)); |
| } |
| PassMode::Pair(..) => { |
| let a = llvm::get_param(bx.llfn(), llarg_idx as c_uint); |
| bx.set_value_name(a, &(name.clone() + ".0")); |
| llarg_idx += 1; |
| |
| let b = llvm::get_param(bx.llfn(), llarg_idx as c_uint); |
| bx.set_value_name(b, &(name + ".1")); |
| llarg_idx += 1; |
| |
| return local(OperandRef { |
| val: OperandValue::Pair(a, b), |
| layout: arg.layout |
| }); |
| } |
| _ => {} |
| } |
| } |
| |
| let place = if arg.is_indirect() { |
| // Don't copy an indirect argument to an alloca, the caller |
| // already put it in a temporary alloca and gave it up. |
| // FIXME: lifetimes |
| let llarg = llvm::get_param(bx.llfn(), llarg_idx as c_uint); |
| bx.set_value_name(llarg, &name); |
| llarg_idx += 1; |
| PlaceRef::new_sized(llarg, arg.layout, arg.layout.align) |
| } else { |
| let tmp = PlaceRef::alloca(bx, arg.layout, &name); |
| arg.store_fn_arg(bx, &mut llarg_idx, tmp); |
| tmp |
| }; |
| arg_scope.map(|scope| { |
| // Is this a regular argument? |
| if arg_index > 0 || mir.upvar_decls.is_empty() { |
| // The Rust ABI passes indirect variables using a pointer and a manual copy, so we |
| // need to insert a deref here, but the C ABI uses a pointer and a copy using the |
| // byval attribute, for which LLVM does the deref itself, so we must not add it. |
| let mut variable_access = VariableAccess::DirectVariable { |
| alloca: place.llval |
| }; |
| |
| if let PassMode::Indirect(ref attrs) = arg.mode { |
| if !attrs.contains(ArgAttribute::ByVal) { |
| variable_access = VariableAccess::IndirectVariable { |
| alloca: place.llval, |
| address_operations: &deref_op, |
| }; |
| } |
| } |
| |
| declare_local( |
| bx, |
| &fx.debug_context, |
| arg_decl.name.unwrap_or(keywords::Invalid.name()), |
| arg.layout.ty, |
| scope, |
| variable_access, |
| VariableKind::ArgumentVariable(arg_index + 1), |
| DUMMY_SP |
| ); |
| return; |
| } |
| |
| // Or is it the closure environment? |
| let (closure_layout, env_ref) = match arg.layout.ty.sty { |
| ty::TyRef(_, mt) | ty::TyRawPtr(mt) => (bx.cx.layout_of(mt.ty), true), |
| _ => (arg.layout, false) |
| }; |
| |
| let upvar_tys = match closure_layout.ty.sty { |
| ty::TyClosure(def_id, substs) | |
| ty::TyGenerator(def_id, substs, _) => substs.upvar_tys(def_id, tcx), |
| _ => bug!("upvar_decls with non-closure arg0 type `{}`", closure_layout.ty) |
| }; |
| |
| // Store the pointer to closure data in an alloca for debuginfo |
| // because that's what the llvm.dbg.declare intrinsic expects. |
| |
| // FIXME(eddyb) this shouldn't be necessary but SROA seems to |
| // mishandle DW_OP_plus not preceded by DW_OP_deref, i.e. it |
| // doesn't actually strip the offset when splitting the closure |
| // environment into its components so it ends up out of bounds. |
| let env_ptr = if !env_ref { |
| let scratch = PlaceRef::alloca(bx, |
| bx.cx.layout_of(tcx.mk_mut_ptr(arg.layout.ty)), |
| "__debuginfo_env_ptr"); |
| bx.store(place.llval, scratch.llval, scratch.align); |
| scratch.llval |
| } else { |
| place.llval |
| }; |
| |
| for (i, (decl, ty)) in mir.upvar_decls.iter().zip(upvar_tys).enumerate() { |
| let byte_offset_of_var_in_env = closure_layout.fields.offset(i).bytes(); |
| |
| let ops = unsafe { |
| [llvm::LLVMRustDIBuilderCreateOpDeref(), |
| llvm::LLVMRustDIBuilderCreateOpPlus(), |
| byte_offset_of_var_in_env as i64, |
| llvm::LLVMRustDIBuilderCreateOpDeref()] |
| }; |
| |
| // The environment and the capture can each be indirect. |
| |
| // FIXME(eddyb) see above why we have to keep |
| // a pointer in an alloca for debuginfo atm. |
| let mut ops = if env_ref || true { &ops[..] } else { &ops[1..] }; |
| |
| let ty = if let (true, &ty::TyRef(_, mt)) = (decl.by_ref, &ty.sty) { |
| mt.ty |
| } else { |
| ops = &ops[..ops.len() - 1]; |
| ty |
| }; |
| |
| let variable_access = VariableAccess::IndirectVariable { |
| alloca: env_ptr, |
| address_operations: &ops |
| }; |
| declare_local( |
| bx, |
| &fx.debug_context, |
| decl.debug_name, |
| ty, |
| scope, |
| variable_access, |
| VariableKind::CapturedVariable, |
| DUMMY_SP |
| ); |
| } |
| }); |
| LocalRef::Place(place) |
| }).collect() |
| } |
| |
| mod analyze; |
| mod block; |
| mod constant; |
| pub mod place; |
| pub mod operand; |
| mod rvalue; |
| mod statement; |
