Iasm and obj lowering for advanced switch lowering.

Jump table emission is delayed until offsets are known. X86 local jumps can be
near or far. Sanboxing is applied to indirect jumps from jump table.

BUG=
R=stichnot@chromium.org, jvoung

Review URL: https://codereview.chromium.org/1257283004.

src/IceInstX86BaseImpl.h

diff --git a/src/IceInstX86BaseImpl.h b/src/IceInstX86BaseImpl.h
index f80073e..137e295 100644
--- a/src/IceInstX86BaseImpl.h
+++ b/src/IceInstX86BaseImpl.h
@@ -105,10 +105,10 @@
 InstX86Br<Machine>::InstX86Br(
     Cfg *Func, const CfgNode *TargetTrue, const CfgNode *TargetFalse,
     const InstX86Label<Machine> *Label,
-    typename InstX86Base<Machine>::Traits::Cond::BrCond Condition)
+    typename InstX86Base<Machine>::Traits::Cond::BrCond Condition, Mode Kind)
     : InstX86Base<Machine>(Func, InstX86Base<Machine>::Br, 0, nullptr),
       Condition(Condition), TargetTrue(TargetTrue), TargetFalse(TargetFalse),
-      Label(Label) {}
+      Label(Label), Kind(Kind) {}
 
 template <class Machine>
 bool InstX86Br<Machine>::optimizeBranch(const CfgNode *NextNode) {
@@ -404,7 +404,7 @@
 void InstX86Label<Machine>::emitIAS(const Cfg *Func) const {
   typename InstX86Base<Machine>::Traits::Assembler *Asm =
       Func->getAssembler<typename InstX86Base<Machine>::Traits::Assembler>();
-  Asm->BindLocalLabel(Number);
+  Asm->bindLocalLabel(Number);
 }
 
 template <class Machine>
@@ -446,31 +446,26 @@
   typename InstX86Base<Machine>::Traits::Assembler *Asm =
       Func->getAssembler<typename InstX86Base<Machine>::Traits::Assembler>();
   if (Label) {
-    class Label *L = Asm->GetOrCreateLocalLabel(Label->getNumber());
-    // In all these cases, local Labels should only be used for Near.
-    const bool Near = true;
+    class Label *L = Asm->getOrCreateLocalLabel(Label->getNumber());
     if (Condition == InstX86Base<Machine>::Traits::Cond::Br_None) {
-      Asm->jmp(L, Near);
+      Asm->jmp(L, isNear());
     } else {
-      Asm->j(Condition, L, Near);
+      Asm->j(Condition, L, isNear());
     }
   } else {
-    // Pessimistically assume it's far. This only affects Labels that
-    // are not Bound.
-    const bool Near = false;
     if (Condition == InstX86Base<Machine>::Traits::Cond::Br_None) {
       class Label *L =
-          Asm->GetOrCreateCfgNodeLabel(getTargetFalse()->getIndex());
+          Asm->getOrCreateCfgNodeLabel(getTargetFalse()->getIndex());
       assert(!getTargetTrue());
-      Asm->jmp(L, Near);
+      Asm->jmp(L, isNear());
     } else {
       class Label *L =
-          Asm->GetOrCreateCfgNodeLabel(getTargetTrue()->getIndex());
-      Asm->j(Condition, L, Near);
+          Asm->getOrCreateCfgNodeLabel(getTargetTrue()->getIndex());
+      Asm->j(Condition, L, isNear());
       if (getTargetFalse()) {
         class Label *L2 =
-            Asm->GetOrCreateCfgNodeLabel(getTargetFalse()->getIndex());
-        Asm->jmp(L2, Near);
+            Asm->getOrCreateCfgNodeLabel(getTargetFalse()->getIndex());
+        Asm->jmp(L2, isNear());
       }
     }
   }
@@ -498,6 +493,8 @@
       Str << ", label %" << getTargetFalse()->getName();
     }
   }
+
+  Str << " // (" << (isNear() ? "near" : "far") << " jump)";
 }
 
 template <class Machine> void InstX86Jmp<Machine>::emit(const Cfg *Func) const {