Introduce globalsym_addr.

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

lib/cretonne/meta/base/instructions.py

@@ -389,6 +389,14 @@ global_addr = Instruction(
         """,
         ins=GV, outs=addr)
 
+# A specialized form of global_addr instructions that only handles
+# symbolic names.
+globalsym_addr = Instruction(
+        'globalsym_addr', r"""
+        Compute the address of global variable GV, which is a symbolic name.
+        """,
+        ins=GV, outs=addr)
+
 #
 # WebAssembly bounds-checked heap accesses.
 #

lib/cretonne/meta/isa/intel/encodings.py

@@ -271,6 +271,13 @@ I32.enc(base.func_addr.i32, *r.allones_fnaddr4(0xb8),
 I64.enc(base.func_addr.i64, *r.allones_fnaddr8.rex(0xb8, w=1),
         isap=allones_funcaddrs)
 
+#
+# Global addresses.
+#
+
+I32.enc(base.globalsym_addr.i32, *r.gvaddr4(0xb8))
+I64.enc(base.globalsym_addr.i64, *r.gvaddr8.rex(0xb8, w=1))
+
 #
 # Call/return
 #

lib/cretonne/meta/isa/intel/recipes.py

@@ -9,7 +9,7 @@ from base.formats import Unary, UnaryImm, Binary, BinaryImm, MultiAry
 from base.formats import Trap, Call, IndirectCall, Store, Load
 from base.formats import IntCompare, FloatCompare, IntCond, FloatCond
 from base.formats import Jump, Branch, BranchInt, BranchFloat
-from base.formats import Ternary, FuncAddr
+from base.formats import Ternary, FuncAddr, UnaryGlobalVar
 from base.formats import RegMove, RegSpill, RegFill
 from .registers import GPR, ABCD, FPR, GPR8, FPR8, FLAG, StackGPR32, StackFPR32
 from .defs import supported_floatccs
@@ -510,6 +510,24 @@ allones_fnaddr8 = TailRecipe(
         sink.put8(!0);
         ''')
 
+# XX+rd id with Abs4 globalsym relocation.
+gvaddr4 = TailRecipe(
+        'gvaddr4', UnaryGlobalVar, size=4, ins=(), outs=GPR,
+        emit='''
+        PUT_OP(bits | (out_reg0 & 7), rex1(out_reg0), sink);
+        sink.reloc_globalsym(RelocKind::Abs4.into(), global_var);
+        sink.put4(0);
+        ''')
+
+# XX+rd iq with Abs8 globalsym relocation.
+gvaddr8 = TailRecipe(
+        'gvaddr8', UnaryGlobalVar, size=8, ins=(), outs=GPR,
+        emit='''
+        PUT_OP(bits | (out_reg0 & 7), rex1(out_reg0), sink);
+        sink.reloc_globalsym(RelocKind::Abs8.into(), global_var);
+        sink.put8(0);
+        ''')
+
 #
 # Store recipes.
 #

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);
+}