src/librustc_codegen_ssa/mir/statement.rs

   1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use rustc::mir;
  12
  13 use traits::BuilderMethods;
  14 use super::FunctionCx;
  15 use super::LocalRef;
  16 use super::OperandValue;
  17 use traits::*;
  18
  19 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
  20     pub fn codegen_statement(
  21         &mut self,
  22         mut bx: Bx,
  23         statement: &mir::Statement<'tcx>
  24     ) -> Bx {
  25         debug!("codegen_statement(statement={:?})", statement);
  26
  27         self.set_debug_loc(&mut bx, statement.source_info);
  28         match statement.kind {
  29             mir::StatementKind::Assign(ref place, ref rvalue) => {
  30                 if let mir::Place::Local(index) = *place {
  31                     match self.locals[index] {
  32                         LocalRef::Place(cg_dest) => {
  33                             self.codegen_rvalue(bx, cg_dest, rvalue)
  34                         }
  35                         LocalRef::UnsizedPlace(cg_indirect_dest) => {
  36                             self.codegen_rvalue_unsized(bx, cg_indirect_dest, rvalue)
  37                         }
  38                         LocalRef::Operand(None) => {
  39                             let (bx, operand) = self.codegen_rvalue_operand(bx, rvalue);
  40                             self.locals[index] = LocalRef::Operand(Some(operand));
  41                             bx
  42                         }
  43                         LocalRef::Operand(Some(op)) => {
  44                             if !op.layout.is_zst() {
  45                                 span_bug!(statement.source_info.span,
  46                                           "operand {:?} already assigned",
  47                                           rvalue);
  48                             }
  49
  50                             // If the type is zero-sized, it's already been set here,
  51                             // but we still need to make sure we codegen the operand
  52                             self.codegen_rvalue_operand(bx, rvalue).0
  53                         }
  54                     }
  55                 } else {
  56                     let cg_dest = self.codegen_place(&mut bx, place);
  57                     self.codegen_rvalue(bx, cg_dest, rvalue)
  58                 }
  59             }
  60             mir::StatementKind::SetDiscriminant{ref place, variant_index} => {
  61                 self.codegen_place(&mut bx, place)
  62                     .codegen_set_discr(&mut bx, variant_index);
  63                 bx
  64             }
  65             mir::StatementKind::StorageLive(local) => {
  66                 if let LocalRef::Place(cg_place) = self.locals[local] {
  67                     cg_place.storage_live(&mut bx);
  68                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  69                     cg_indirect_place.storage_live(&mut bx);
  70                 }
  71                 bx
  72             }
  73             mir::StatementKind::StorageDead(local) => {
  74                 if let LocalRef::Place(cg_place) = self.locals[local] {
  75                     cg_place.storage_dead(&mut bx);
  76                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  77                     cg_indirect_place.storage_dead(&mut bx);
  78                 }
  79                 bx
  80             }
  81             mir::StatementKind::InlineAsm { ref asm, ref outputs, ref inputs } => {
  82                 let outputs = outputs.iter().map(|output| {
  83                     self.codegen_place(&mut bx, output)
  84                 }).collect();
  85
  86                 let input_vals = inputs.iter()
  87                     .fold(Vec::with_capacity(inputs.len()), |mut acc, (span, input)| {
  88                         let op = self.codegen_operand(&mut bx, input);
  89                         if let OperandValue::Immediate(_) = op.val {
  90                             acc.push(op.immediate());
  91                         } else {
  92                             span_err!(bx.sess(), span.to_owned(), E0669,
  93                                      "invalid value for constraint in inline assembly");
  94                         }
  95                         acc
  96                 });
  97
  98                 if input_vals.len() == inputs.len() {
  99                     let res = bx.codegen_inline_asm(asm, outputs, input_vals);
 100                     if !res {
 101                         span_err!(bx.sess(), statement.source_info.span, E0668,
 102                                   "malformed inline assembly");
 103                     }
 104                 }
 105                 bx
 106             }
 107             mir::StatementKind::FakeRead(..) |
 108             mir::StatementKind::Retag { .. } |
 109             mir::StatementKind::AscribeUserType(..) |
 110             mir::StatementKind::Nop => bx,
 111         }
 112     }
 113 }