Introduce globalsym_addr.

This is an instruction used in legalization of GlobalVarData::Sym global
variables.

lib/cretonne/src/binemit/memorysink.rs

@@ -14,7 +14,7 @@
 //! relocations to a `RelocSink` trait object. Relocations are less frequent than the
 //! `CodeSink::put*` methods, so the performance impact of the virtual callbacks is less severe.
 
-use ir::{Ebb, FuncRef, JumpTable};
+use ir::{Ebb, FuncRef, GlobalVar, JumpTable};
 use super::{CodeSink, CodeOffset, Reloc};
 use std::ptr::write_unaligned;
 
@@ -54,6 +54,11 @@ pub trait RelocSink {
     /// Add a relocation referencing an external function at the current offset.
     fn reloc_func(&mut self, CodeOffset, Reloc, FuncRef);
 
+    /// Add a relocation referencing an external global variable symbol at the
+    /// current offset.
+    fn reloc_globalsym(&mut self, CodeOffset, Reloc, GlobalVar);
+
+    /// Add a relocation referencing a jump table.
     /// Add a relocation referencing a jump table.
     fn reloc_jt(&mut self, CodeOffset, Reloc, JumpTable);
 }
@@ -101,6 +106,11 @@ impl<'a> CodeSink for MemoryCodeSink<'a> {
         self.relocs.reloc_func(ofs, rel, func);
     }
 
+    fn reloc_globalsym(&mut self, rel: Reloc, global: GlobalVar) {
+        let ofs = self.offset();
+        self.relocs.reloc_globalsym(ofs, rel, global);
+    }
+
     fn reloc_jt(&mut self, rel: Reloc, jt: JumpTable) {
         let ofs = self.offset();
         self.relocs.reloc_jt(ofs, rel, jt);

lib/cretonne/src/binemit/mod.rs

@@ -9,7 +9,7 @@ mod memorysink;
 pub use self::relaxation::relax_branches;
 pub use self::memorysink::{MemoryCodeSink, RelocSink};
 
-use ir::{Ebb, FuncRef, JumpTable, Function, Inst};
+use ir::{Ebb, FuncRef, GlobalVar, JumpTable, Function, Inst};
 use regalloc::RegDiversions;
 
 /// Offset in bytes from the beginning of the function.
@@ -47,6 +47,10 @@ pub trait CodeSink {
     /// Add a relocation referencing an external function at the current offset.
     fn reloc_func(&mut self, Reloc, FuncRef);
 
+    /// Add a relocation referencing an external global variable symbol at the
+    /// current offset. This is only used for `GlobalVarData::Sym` globals.
+    fn reloc_globalsym(&mut self, Reloc, GlobalVar);
+
     /// Add a relocation referencing a jump table.
     fn reloc_jt(&mut self, Reloc, JumpTable);
 }

lib/cretonne/src/legalizer/globalvar.rs

@@ -21,7 +21,7 @@ pub fn expand_global_addr(inst: ir::Inst, func: &mut ir::Function, _cfg: &mut Co
     match func.global_vars[gv] {
         ir::GlobalVarData::VmCtx { offset } => vmctx_addr(inst, func, offset.into()),
         ir::GlobalVarData::Deref { base, offset } => deref_addr(inst, func, base, offset.into()),
-        ir::GlobalVarData::Sym { .. } => (),
+        ir::GlobalVarData::Sym { .. } => globalsym(inst, func, gv),
     }
 }
 
@@ -50,3 +50,9 @@ fn deref_addr(inst: ir::Inst, func: &mut ir::Function, base: ir::GlobalVar, offs
     let base_ptr = pos.ins().load(ptr_ty, ir::MemFlags::new(), base_addr, 0);
     pos.func.dfg.replace(inst).iadd_imm(base_ptr, offset);
 }
+
+/// Expand a `global_addr` instruction for a symbolic name global.
+fn globalsym(inst: ir::Inst, func: &mut ir::Function, gv: ir::GlobalVar) {
+    let ptr_ty = func.dfg.value_type(func.dfg.first_result(inst));
+    func.dfg.replace(inst).globalsym_addr(ptr_ty, gv);
+}