Fix race condition in jump table list creation

src/IceSwitchLowering.h

Index: src/IceSwitchLowering.h
diff --git a/src/IceSwitchLowering.h b/src/IceSwitchLowering.h
index 8ac1842ca8f07c613173ad853185f378f4cfafa0..a6ae9a9cb512643b13728727926a67a502b4db53 100644
--- a/src/IceSwitchLowering.h
+++ b/src/IceSwitchLowering.h
@@ -81,10 +81,10 @@ class JumpTableData {
   JumpTableData &operator=(const JumpTableData &) = delete;
 
 public:
-  JumpTableData(IceString FuncName, SizeT Id, SizeT NumTargets)
-      : FuncName(FuncName), Id(Id) {
-    TargetOffsets.reserve(NumTargets);
-  }
+  using TargetList = std::vector<intptr_t>;
+
+  JumpTableData(IceString FuncName, SizeT Id, const TargetList &TargetOffsets)

[Jim Stichnoth, 2015/11/20 01:02:20]

const IceString &FuncName

[sehr, 2015/11/20 05:43:15]

Done.

+      : FuncName(FuncName), Id(Id), TargetOffsets(TargetOffsets) { }
   JumpTableData(const JumpTableData &) = default;
   JumpTableData(JumpTableData &&) = default;
   JumpTableData &operator=(JumpTableData &&) = default;
@@ -93,14 +93,14 @@ public:
 
   const IceString &getFunctionName() const { return FuncName; }
   SizeT getId() const { return Id; }
-  const std::vector<intptr_t> &getTargetOffsets() const {
+  const TargetList &getTargetOffsets() const {
     return TargetOffsets;
   }
 
 private:
   IceString FuncName;

[Jim Stichnoth, 2015/11/20 01:02:20]

Can this be const IceString?

[sehr, 2015/11/20 05:43:15]

Looks like move operations don't work if I do this.

   SizeT Id;
-  std::vector<intptr_t> TargetOffsets;
+  TargetList TargetOffsets;
 };
 
 using JumpTableDataList = std::vector<JumpTableData>;