src/librustc_codegen_ssa/mir/statement.rs

   1 use rustc::mir;
   2
   3 use crate::traits::BuilderMethods;
   4 use super::FunctionCx;
   5 use super::LocalRef;
   6 use super::OperandValue;
   7 use crate::traits::*;
   8
   9 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
  10     pub fn codegen_statement(
  11         &mut self,
  12         mut bx: Bx,
  13         statement: &mir::Statement<'tcx>
  14     ) -> Bx {
  15         debug!("codegen_statement(statement={:?})", statement);
  16
  17         self.set_debug_loc(&mut bx, statement.source_info);
  18         match statement.kind {
  19             mir::StatementKind::Assign(ref place, ref rvalue) => {
  20                 if let mir::Place {
  21                     base: mir::PlaceBase::Local(index),
  22                     projection: None,
  23                 } = *place {
  24                     match self.locals[index] {
  25                         LocalRef::Place(cg_dest) => {
  26                             self.codegen_rvalue(bx, cg_dest, rvalue)
  27                         }
  28                         LocalRef::UnsizedPlace(cg_indirect_dest) => {
  29                             self.codegen_rvalue_unsized(bx, cg_indirect_dest, rvalue)
  30                         }
  31                         LocalRef::Operand(None) => {
  32                             let (bx, operand) = self.codegen_rvalue_operand(bx, rvalue);
  33                             self.locals[index] = LocalRef::Operand(Some(operand));
  34                             bx
  35                         }
  36                         LocalRef::Operand(Some(op)) => {
  37                             if !op.layout.is_zst() {
  38                                 span_bug!(statement.source_info.span,
  39                                           "operand {:?} already assigned",
  40                                           rvalue);
  41                             }
  42
  43                             // If the type is zero-sized, it's already been set here,
  44                             // but we still need to make sure we codegen the operand
  45                             self.codegen_rvalue_operand(bx, rvalue).0
  46                         }
  47                     }
  48                 } else {
  49                     let cg_dest = self.codegen_place(&mut bx, &place.as_ref());
  50                     self.codegen_rvalue(bx, cg_dest, rvalue)
  51                 }
  52             }
  53             mir::StatementKind::SetDiscriminant{ref place, variant_index} => {
  54                 self.codegen_place(&mut bx, &place.as_ref())
  55                     .codegen_set_discr(&mut bx, variant_index);
  56                 bx
  57             }
  58             mir::StatementKind::StorageLive(local) => {
  59                 if let LocalRef::Place(cg_place) = self.locals[local] {
  60                     cg_place.storage_live(&mut bx);
  61                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  62                     cg_indirect_place.storage_live(&mut bx);
  63                 }
  64                 bx
  65             }
  66             mir::StatementKind::StorageDead(local) => {
  67                 if let LocalRef::Place(cg_place) = self.locals[local] {
  68                     cg_place.storage_dead(&mut bx);
  69                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  70                     cg_indirect_place.storage_dead(&mut bx);
  71                 }
  72                 bx
  73             }
  74             mir::StatementKind::InlineAsm(ref asm) => {
  75                 let outputs = asm.outputs.iter().map(|output| {
  76                     self.codegen_place(&mut bx, &output.as_ref())
  77                 }).collect();
  78
  79                 let input_vals = asm.inputs.iter()
  80                     .fold(Vec::with_capacity(asm.inputs.len()), |mut acc, (span, input)| {
  81                         let op = self.codegen_operand(&mut bx, input);
  82                         if let OperandValue::Immediate(_) = op.val {
  83                             acc.push(op.immediate());
  84                         } else {
  85                             span_err!(bx.sess(), span.to_owned(), E0669,
  86                                      "invalid value for constraint in inline assembly");
  87                         }
  88                         acc
  89                 });
  90
  91                 if input_vals.len() == asm.inputs.len() {
  92                     let res = bx.codegen_inline_asm(&asm.asm, outputs, input_vals);
  93                     if !res {
  94                         span_err!(bx.sess(), statement.source_info.span, E0668,
  95                                   "malformed inline assembly");
  96                     }
  97                 }
  98                 bx
  99             }
 100             mir::StatementKind::FakeRead(..) |
 101             mir::StatementKind::Retag { .. } |
 102             mir::StatementKind::AscribeUserType(..) |
 103             mir::StatementKind::Nop => bx,
 104         }
 105     }
 106 }