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(box(ref place, ref rvalue)) => {
  20                 if let Some(index) = place.as_local() {
  21                     match self.locals[index] {
  22                         LocalRef::Place(cg_dest) => {
  23                             self.codegen_rvalue(bx, cg_dest, rvalue)
  24                         }
  25                         LocalRef::UnsizedPlace(cg_indirect_dest) => {
  26                             self.codegen_rvalue_unsized(bx, cg_indirect_dest, rvalue)
  27                         }
  28                         LocalRef::Operand(None) => {
  29                             let (mut bx, operand) = self.codegen_rvalue_operand(bx, rvalue);
  30                             if let Some(name) = self.mir.local_decls[index].name {
  31                                 match operand.val {
  32                                     OperandValue::Ref(x, ..) |
  33                                     OperandValue::Immediate(x) => {
  34                                         bx.set_var_name(x, name);
  35                                     }
  36                                     OperandValue::Pair(a, b) => {
  37                                         // FIXME(eddyb) these are scalar components,
  38                                         // maybe extract the high-level fields?
  39                                         bx.set_var_name(a, format_args!("{}.0", name));
  40                                         bx.set_var_name(b, format_args!("{}.1", name));
  41                                     }
  42                                 }
  43                             }
  44                             self.locals[index] = LocalRef::Operand(Some(operand));
  45                             bx
  46                         }
  47                         LocalRef::Operand(Some(op)) => {
  48                             if !op.layout.is_zst() {
  49                                 span_bug!(statement.source_info.span,
  50                                           "operand {:?} already assigned",
  51                                           rvalue);
  52                             }
  53
  54                             // If the type is zero-sized, it's already been set here,
  55                             // but we still need to make sure we codegen the operand
  56                             self.codegen_rvalue_operand(bx, rvalue).0
  57                         }
  58                     }
  59                 } else {
  60                     let cg_dest = self.codegen_place(&mut bx, &place.as_ref());
  61                     self.codegen_rvalue(bx, cg_dest, rvalue)
  62                 }
  63             }
  64             mir::StatementKind::SetDiscriminant{box ref place, variant_index} => {
  65                 self.codegen_place(&mut bx, &place.as_ref())
  66                     .codegen_set_discr(&mut bx, variant_index);
  67                 bx
  68             }
  69             mir::StatementKind::StorageLive(local) => {
  70                 if let LocalRef::Place(cg_place) = self.locals[local] {
  71                     cg_place.storage_live(&mut bx);
  72                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  73                     cg_indirect_place.storage_live(&mut bx);
  74                 }
  75                 bx
  76             }
  77             mir::StatementKind::StorageDead(local) => {
  78                 if let LocalRef::Place(cg_place) = self.locals[local] {
  79                     cg_place.storage_dead(&mut bx);
  80                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  81                     cg_indirect_place.storage_dead(&mut bx);
  82                 }
  83                 bx
  84             }
  85             mir::StatementKind::InlineAsm(ref asm) => {
  86                 let outputs = asm.outputs.iter().map(|output| {
  87                     self.codegen_place(&mut bx, &output.as_ref())
  88                 }).collect();
  89
  90                 let input_vals = asm.inputs.iter()
  91                     .fold(Vec::with_capacity(asm.inputs.len()), |mut acc, (span, input)| {
  92                         let op = self.codegen_operand(&mut bx, input);
  93                         if let OperandValue::Immediate(_) = op.val {
  94                             acc.push(op.immediate());
  95                         } else {
  96                             span_err!(bx.sess(), span.to_owned(), E0669,
  97                                      "invalid value for constraint in inline assembly");
  98                         }
  99                         acc
 100                 });
 101
 102                 if input_vals.len() == asm.inputs.len() {
 103                     let res = bx.codegen_inline_asm(
 104                         &asm.asm,
 105                         outputs,
 106                         input_vals,
 107                         statement.source_info.span,
 108                     );
 109                     if !res {
 110                         span_err!(bx.sess(), statement.source_info.span, E0668,
 111                                   "malformed inline assembly");
 112                     }
 113                 }
 114                 bx
 115             }
 116             mir::StatementKind::FakeRead(..) |
 117             mir::StatementKind::Retag { .. } |
 118             mir::StatementKind::AscribeUserType(..) |
 119             mir::StatementKind::Nop => bx,
 120         }
 121     }
 122 }