Subzero: Initial implementation of multithreaded translation.

src/IceTargetLoweringX8632.h

Index: src/IceTargetLoweringX8632.h
diff --git a/src/IceTargetLoweringX8632.h b/src/IceTargetLoweringX8632.h
index cd82d7ae9427c266e67906f2374e901727f492ba..eac38283e653c4809d5cd793b368e646014d9257 100644
--- a/src/IceTargetLoweringX8632.h
+++ b/src/IceTargetLoweringX8632.h
@@ -56,7 +56,7 @@ public:
   void lowerArguments() override;
   void addProlog(CfgNode *Node) override;
   void addEpilog(CfgNode *Node) override;
-  void emitConstants() const override;
+  static void emitConstants(GlobalContext *Ctx);

[JF, 2015/01/22 20:50:56]

Why not keep this as override, and implement per target?

I wouldn't go the static route, I'd instead do static polymorphism through
templates (which is easy to move towards from virtual functions).

[Jim Stichnoth, 2015/01/23 07:55:55]

The reason was explained in the CL description:

"TargetLowering::emitConstants() and related methods are changed to be static,
so that a valid TargetLowering object isn't required.  This is because the
TargetLowering object wants to hold a valid Cfg, and none really exists after
all functions are translated and the constant pool is ready for emission."

That is, emitConstants has nothing to do with a Cfg, and only needs to know the
GlobalContext in which the constant pool is stored.

Not sure why I didn't think of this before, but the existing
TargetGlobalInitLowering abstract class, and its target-specific concrete class,
is the perfect place for this.  I changed the name to TargetGlobalLowering to
reflect the more general functionality.

   SizeT makeNextLabelNumber() { return NextLabelNumber++; }
   // Ensure that a 64-bit Variable has been split into 2 32-bit
   // Variables, creating them if necessary.  This is needed for all
@@ -487,7 +487,7 @@ protected:
 
 private:
   ~TargetX8632() override {}
-  template <typename T> void emitConstantPool() const;
+  template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
 class TargetGlobalInitX8632 : public TargetGlobalInitLowering {