First pass at emitIAS for branches and binding labels

src/IceInstX8632.h

 //===- subzero/src/IceInstX8632.h - Low-level x86 instructions --*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the InstX8632 and OperandX8632 classes and
@@ skipping 256 matching lines @@
 
 protected:
   InstX8632(Cfg *Func, InstKindX8632 Kind, SizeT Maxsrcs, Variable *Dest)
       : InstTarget(Func, static_cast<InstKind>(Kind), Maxsrcs, Dest) {}
   ~InstX8632() override {}
   static bool isClassof(const Inst *Inst, InstKindX8632 MyKind) {
     return Inst->getKind() == static_cast<InstKind>(MyKind);
   }
 };
 
-// InstX8632Label represents an intra-block label that is the
-// target of an intra-block branch.  These are used for lowering i1
-// calculations, Select instructions, and 64-bit compares on a 32-bit
-// architecture, without basic block splitting.  Basic block splitting
-// is not so desirable for several reasons, one of which is the impact
-// on decisions based on whether a variable's live range spans
-// multiple basic blocks.
+// InstX8632Label represents an intra-block label that is the target
+// of an intra-block branch.  The offset between the label and the
+// branch must be fit into one byte (considered "near").  These are
+// used for lowering i1 calculations, Select instructions, and 64-bit
+// compares on a 32-bit architecture, without basic block splitting.
+// Basic block splitting is not so desirable for several reasons, one
+// of which is the impact on decisions based on whether a variable's
+// live range spans multiple basic blocks.
 //
 // Intra-block control flow must be used with caution.  Consider the
 // sequence for "c = (a >= b ? x : y)".
 //     cmp a, b
 //     br lt, L1
 //     mov c, x
 //     jmp L2
 //   L1:
 //     mov c, y
 //   L2:
@@ skipping 20 matching lines @@
 class InstX8632Label : public InstX8632 {
   InstX8632Label(const InstX8632Label &) = delete;
   InstX8632Label &operator=(const InstX8632Label &) = delete;
 
 public:
   static InstX8632Label *create(Cfg *Func, TargetX8632 *Target) {
     return new (Func->allocate<InstX8632Label>()) InstX8632Label(Func, Target);
   }
   uint32_t getEmitInstCount() const override { return 0; }
   IceString getName(const Cfg *Func) const;
+  SizeT getNumber() const { return Number; }
   void emit(const Cfg *Func) const override;
-  // TODO(jvoung): Filler in.
-  void emitIAS(const Cfg *Func) const override { emit(Func); }
+  void emitIAS(const Cfg *Func) const override;
   void dump(const Cfg *Func) const override;
 
 private:
   InstX8632Label(Cfg *Func, TargetX8632 *Target);
   ~InstX8632Label() override {}
-  SizeT Number; // used only for unique label string generation
+  SizeT Number; // used for unique label generation.
 };
 
 // Conditional and unconditional branch instruction.
 class InstX8632Br : public InstX8632 {
   InstX8632Br(const InstX8632Br &) = delete;
   InstX8632Br &operator=(const InstX8632Br &) = delete;
 
 public:
   // Create a conditional branch to a node.
   static InstX8632Br *create(Cfg *Func, CfgNode *TargetTrue,
@@ skipping 35 matching lines @@
     uint32_t Sum = 0;
     if (Label)
       ++Sum;
     if (getTargetTrue())
       ++Sum;
     if (getTargetFalse())
       ++Sum;
     return Sum;
   }
   void emit(const Cfg *Func) const override;
-  // TODO(jvoung): Filler in.
-  void emitIAS(const Cfg *Func) const override { emit(Func); }
+  void emitIAS(const Cfg *Func) const override;
   void dump(const Cfg *Func) const override;
   static bool classof(const Inst *Inst) { return isClassof(Inst, Br); }
 
 private:
   InstX8632Br(Cfg *Func, const CfgNode *TargetTrue, const CfgNode *TargetFalse,
               const InstX8632Label *Label, CondX86::BrCond Condition);
   ~InstX8632Br() override {}
   CondX86::BrCond Condition;
   const CfgNode *TargetTrue;
   const CfgNode *TargetFalse;
@@ skipping 1144 matching lines @@
 template <> void InstX8632Pinsr::emitIAS(const Cfg *Func) const;
 template <> void InstX8632Movsx::emitIAS(const Cfg *Func) const;
 template <> void InstX8632Movzx::emitIAS(const Cfg *Func) const;
 template <> void InstX8632Pmull::emitIAS(const Cfg *Func) const;
 template <> void InstX8632Pshufd::emitIAS(const Cfg *Func) const;
 template <> void InstX8632Shufps::emitIAS(const Cfg *Func) const;
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINSTX8632_H