compiler/rustc_codegen_ssa/src/mir/statement.rs

   1 use rustc_errors::struct_span_err;
   2 use rustc_middle::mir;
   3
   4 use super::FunctionCx;
   5 use super::LocalRef;
   6 use super::OperandValue;
   7 use crate::traits::BuilderMethods;
   8 use crate::traits::*;
   9
  10 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
  11     pub fn codegen_statement(&mut self, mut bx: Bx, statement: &mir::Statement<'tcx>) -> Bx {
  12         debug!("codegen_statement(statement={:?})", statement);
  13
  14         self.set_debug_loc(&mut bx, statement.source_info);
  15         match statement.kind {
  16             mir::StatementKind::Assign(box (ref place, ref rvalue)) => {
  17                 if let Some(index) = place.as_local() {
  18                     match self.locals[index] {
  19                         LocalRef::Place(cg_dest) => self.codegen_rvalue(bx, cg_dest, rvalue),
  20                         LocalRef::UnsizedPlace(cg_indirect_dest) => {
  21                             self.codegen_rvalue_unsized(bx, cg_indirect_dest, rvalue)
  22                         }
  23                         LocalRef::Operand(None) => {
  24                             let (mut bx, operand) = self.codegen_rvalue_operand(bx, rvalue);
  25                             self.locals[index] = LocalRef::Operand(Some(operand));
  26                             self.debug_introduce_local(&mut bx, index);
  27                             bx
  28                         }
  29                         LocalRef::Operand(Some(op)) => {
  30                             if !op.layout.is_zst() {
  31                                 span_bug!(
  32                                     statement.source_info.span,
  33                                     "operand {:?} already assigned",
  34                                     rvalue
  35                                 );
  36                             }
  37
  38                             // If the type is zero-sized, it's already been set here,
  39                             // but we still need to make sure we codegen the operand
  40                             self.codegen_rvalue_operand(bx, rvalue).0
  41                         }
  42                     }
  43                 } else {
  44                     let cg_dest = self.codegen_place(&mut bx, place.as_ref());
  45                     self.codegen_rvalue(bx, cg_dest, rvalue)
  46                 }
  47             }
  48             mir::StatementKind::SetDiscriminant { box ref place, variant_index } => {
  49                 self.codegen_place(&mut bx, place.as_ref())
  50                     .codegen_set_discr(&mut bx, variant_index);
  51                 bx
  52             }
  53             mir::StatementKind::StorageLive(local) => {
  54                 if let LocalRef::Place(cg_place) = self.locals[local] {
  55                     cg_place.storage_live(&mut bx);
  56                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  57                     cg_indirect_place.storage_live(&mut bx);
  58                 }
  59                 bx
  60             }
  61             mir::StatementKind::StorageDead(local) => {
  62                 if let LocalRef::Place(cg_place) = self.locals[local] {
  63                     cg_place.storage_dead(&mut bx);
  64                 } else if let LocalRef::UnsizedPlace(cg_indirect_place) = self.locals[local] {
  65                     cg_indirect_place.storage_dead(&mut bx);
  66                 }
  67                 bx
  68             }
  69             mir::StatementKind::LlvmInlineAsm(ref asm) => {
  70                 let outputs = asm
  71                     .outputs
  72                     .iter()
  73                     .map(|output| self.codegen_place(&mut bx, output.as_ref()))
  74                     .collect();
  75
  76                 let input_vals = asm.inputs.iter().fold(
  77                     Vec::with_capacity(asm.inputs.len()),
  78                     |mut acc, (span, input)| {
  79                         let op = self.codegen_operand(&mut bx, input);
  80                         if let OperandValue::Immediate(_) = op.val {
  81                             acc.push(op.immediate());
  82                         } else {
  83                             struct_span_err!(
  84                                 bx.sess(),
  85                                 span.to_owned(),
  86                                 E0669,
  87                                 "invalid value for constraint in inline assembly"
  88                             )
  89                             .emit();
  90                         }
  91                         acc
  92                     },
  93                 );
  94
  95                 if input_vals.len() == asm.inputs.len() {
  96                     let res = bx.codegen_llvm_inline_asm(
  97                         &asm.asm,
  98                         outputs,
  99                         input_vals,
 100                         statement.source_info.span,
 101                     );
 102                     if !res {
 103                         struct_span_err!(
 104                             bx.sess(),
 105                             statement.source_info.span,
 106                             E0668,
 107                             "malformed inline assembly"
 108                         )
 109                         .emit();
 110                     }
 111                 }
 112                 bx
 113             }
 114             mir::StatementKind::Coverage(box ref coverage) => {
 115                 self.codegen_coverage(&mut bx, coverage.clone(), statement.source_info.scope);
 116                 bx
 117             }
 118             mir::StatementKind::CopyNonOverlapping(box mir::CopyNonOverlapping {
 119                 ref src,
 120                 ref dst,
 121                 ref count,
 122             }) => {
 123                 let dst_val = self.codegen_operand(&mut bx, dst);
 124                 let src_val = self.codegen_operand(&mut bx, src);
 125                 let count = self.codegen_operand(&mut bx, count).immediate();
 126                 let pointee_layout = dst_val
 127                     .layout
 128                     .pointee_info_at(&mut bx, rustc_target::abi::Size::ZERO)
 129                     .expect("Expected pointer");
 130                 let bytes = bx.mul(count, bx.const_usize(pointee_layout.size.bytes()));
 131
 132                 let align = pointee_layout.align;
 133                 let dst = dst_val.immediate();
 134                 let src = src_val.immediate();
 135                 bx.memcpy(dst, align, src, align, bytes, crate::MemFlags::empty());
 136                 bx
 137             }
 138             mir::StatementKind::FakeRead(..)
 139             | mir::StatementKind::Retag { .. }
 140             | mir::StatementKind::AscribeUserType(..)
 141             | mir::StatementKind::Nop => bx,
 142         }
 143     }
 144 }